These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Elemental sulfur recovery process  

DOEpatents

An improved catalytic reduction process for the direct recovery of elemental sulfur from various SO.sub.2 -containing industrial gas streams. The catalytic process provides combined high activity and selectivity for the reduction of SO.sub.2 to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over certain catalyst formulations based on cerium oxide. The process is a single-stage, catalytic sulfur recovery process in conjunction with regenerators, such as those used in dry, regenerative flue gas desulfurization or other processes, involving direct reduction of the SO.sub.2 in the regenerator off gas stream to elemental sulfur in the presence of a catalyst.

Flytzani-Stephanopoulos, Maria (Winchester, MA); Hu, Zhicheng (Somerville, MA)

1993-01-01

2

Advanced Sulfur Control Processing  

SciTech Connect

The primary objective of this project is to determine the feasibility of an alternate concept for the regeneration of high temperature desulfurization sorbents in which elemental sulfur, instead of SO{sub 2}, is produced. If successful, this concept will eliminate or alleviate problems caused by the highly exothermic nature of the regeneration reaction, the tendency for metal sulfate formation, and the need to treat the regeneration off-gas to prevent atmospheric SO{sub 2}, emissions. Iron and cerium-based sorbents were chosen on the basis of thermodynamic analysis to determine the feasibility of elemental sulfur production. The ability of both to remove H{sub 2}S during the sulfidation phase is less than that of zinc-based sorbents, and a two-stage desulfurization process will likely be required. Preliminary experimental work used electrobalance reactors to compare the relative rates of reaction of O{sub 2} and H{sub 2}O with FeS. More detailed studies of the regeneration of FeS as well as the sulfidation of CeO{sub 2} and regeneration of Ce{sub 2}O{sub 2}S are being carried out in a laboratory-scale fixed-bed reactor equipped with a unique analytical system which permits semi-continuous analysis of the distribution of elemental sulfur, H{sub 2}S, and SO{sub 2} in the reaction product gas.

Gangwal, S.K.; Portzer, J.W.; Turk, B.S.; Gupta, R. [Research Triangle Inst., Research Triangle Park, NC (United States)

1996-12-31

3

Process for removing sulfur from sulfur-containing gases  

DOEpatents

The present disclosure relates to improved processes for treating hot sulfur-containing flue gas to remove sulfur therefrom. Processes in accorda The government may own certain rights in the present invention pursuant to EPA Cooperative Agreement CR 81-1531.

Rochelle, Gary T. (Austin, TX); Jozewicz, Wojciech (Chapel Hill, NC)

1989-01-01

4

Catalyst for elemental sulfur recovery process  

DOEpatents

A catalytic reduction process is described for the direct recovery of elemental sulfur from various SO[sub 2]-containing industrial gas streams. The catalytic process provides high activity and selectivity, as well as stability in the reaction atmosphere, for the reduction of SO[sub 2] to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over a metal oxide composite catalyst having one of the following empirical formulas: [(FO[sub 2])[sub 1[minus]n](RO)[sub n

Flytzani-Stephanopoulos, M.; Liu, W.

1995-01-24

5

Topsoe`s Wet gas Sulfuric Acid (WSA) process: An alternative technology for recovering refinery sulfur  

Microsoft Academic Search

The Topsoe Wet gas Sulfuric Acid (WSA) process is a catalytic process which produces concentrated sulfuric acid from refinery streams containing sulfur compounds such as HâS (Claus plant feed), Claus plant tail gas, SOâ (FCC off-gas, power plants), and spent sulfuric acid (alkylation acid). The WSA process recovers up to 99.97% of the sulfur value in the stream as concentrated

1995-01-01

6

Process for removing sulfur from coal  

DOEpatents

A process is disclosed for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Aida, T.; Squires, T.G.; Venier, C.G.

1983-08-11

7

Development of enhanced sulfur rejection processes  

SciTech Connect

Research at Virginia Tech led to two complementary concepts for improving the removal of inorganic sulfur from much of the Eastern US coals. One controls the surface properties of coal pyrite (FeS[sub 2]) by electrochemical-.potential control, referred to as the Electrochemically Enhanced Sulfur Rejection (EESR) Process: The second controls the flotation of middlings, i.e., particles composed of pyrite with coal inclusions by using polymeric reagents to react with pyrite and convert the middlings to hydrophilic particles, and is termed the Polymer Enhanced Sulfur Rejection (PESR) Process. These new concepts are based on recent research establishing the two main reasons why flotation fails to remove more than about 50% of the pyritic sulfur from coal: superficial oxidization of liberated pyrite to form polysulfide oxidation products so that a part of the liberated pyrite floats with the coal; and hydrophobic coal inclusions in the middlings dominating their flotation so that the middlings also float with the coal. These new pyritic-sulfur rejection processes do not require significant modifications of existing coal preparation facilities, enhancing their adoptability by the coal industry. It is believed that they can be used simultaneously to achieve both free pyrite and locked pyrite rejection.

Yoon, R.H.; Luttrell, G.; Adel, G.; Richardson, P.E.

1993-03-23

8

Development of enhanced sulfur rejection processes  

SciTech Connect

Research at Virginia Tech led to the development of two complementary concepts for improving the removal of inorganic sulfur from many eastern U.S. coals. These concepts are referred to as Electrochemically Enhanced Sulfur Rejection (EESR) and Polymer Enhanced Sulfur Rejection (PESR) processes. The EESR process uses electrochemical techniques to suppress the formation of hydrophobic oxidation products believed to be responsible for the floatability of coal pyrite. The PESR process uses polymeric reagents that react with pyrite and convert floatable middlings, i.e., composite particles composed of pyrite with coal inclusions, into hydrophilic particles. These new pyritic-sulfur rejection processes do not require significant modifications to existing coal preparation facilities, thereby enhancing their adoptability by the coal industry. It is believed that these processes can be used simultaneously to maximize the rejection of both well-liberated pyrite and composite coal-pyrite particles. The project was initiated on October 1, 1992 and all technical work has been completed. This report is based on the research carried out under Tasks 2-7 described in the project proposal. These tasks include Characterization, Electrochemical Studies, In Situ Monitoring of Reagent Adsorption on Pyrite, Bench Scale Testing of the EESR Process, Bench Scale Testing of the PESR Process, and Modeling and Simulation.

Yoon, R.H.; Luttrell, G.H.; Adel, G.T.; Richardson, P.E.

1996-03-01

9

INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 23. SULFUR, SULFUR OXIDES AND SULFURIC ACID  

EPA Science Inventory

The catalog of Industrial Process Profiles for Environmental Use was developed as an aid in defining the environmental impacts of industrial activity in the United States. Entries for each industry are in consistent format and form separate chapters of the study. The sulfur indus...

10

Catalyst for elemental sulfur recovery process  

DOEpatents

A catalytic reduction process for the direct recovery of elemental sulfur from various SO.sub.2 -containing industrial gas streams. The catalytic process provides high activity and selectivity, as well as stability in the reaction atmosphere, for the reduction of SO.sub.2 to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over a metal oxide composite catalyst having one of the following empirical formulas: [(OF.sub.2).sub.1-n (RO.sub.1)n].sub.1-k M.sub.k, [(FO.sub.2).sub.1-n (RO.sub.1.5).sub.n ].sub.1-k M.sub.k, or [Ln.sub.x Zr.sub.1-x O.sub.2-0.5x ].sub.1-k M.sub.k wherein FO.sub.2 is a fluorite-type oxide; RO represents an alkaline earth oxide; RO.sub.1.5 is a Group IIIB or rare earth oxide; Ln is a rare earth element having an atomic number from 57 to 65 or mixtures thereof; M is a transition metal or a mixture of transition metals; n is a number having a value from 0.0 to 0.35; k is a number having a value from 0.0 to about 0.5; and x is a number having a value from about 0.45 to about 0.55.

Flytzani-Stephanopoulos, Maria (Winchester, MA); Liu, Wei (Cambridge, MA)

1995-01-01

11

Process for the manufacture of sulfur or sulfuric acid from coke oven gas  

Microsoft Academic Search

A process for the complete elimination of ammonia and hydrogen sulfide from coke oven gases is described which does not lead to the occurrence of sulfur dioxide-containing condensates as in prior-art methods. Most of the hydrogen sulfide combustion gases are cooled only to the point where elementary sulfur condenses out on the cooler bottom. The process initially involves scrubbing the

G. Wunderlich; H. Weber

1974-01-01

12

Processing of the Pyrite Concentrates to Generate Sulfurous Anhydride for Sulfuric Acid Production  

Microsoft Academic Search

The results of two-stage roasting of pyrite concentrate with air blowing and the principle scheme of the process are presented in the report. The results of experimental sulfuric acid production tests using pyrite concentrate to generate sulfurous rich gas containing 0.1 - 0.15% of sulphur trioxide are shown. Comparative characteristics with technologies known for the present are given.

T. A. Chepushtanova; V. A. Luganov

13

Microbial Architecture of Environmental Sulfur Processes: A  

E-print Network

potential impacts on water quality, including acid generation in acid mine drainage (AMD) environments, 2009. Accepted July 9, 2009. Microbial oxidation of sulfur-rich mining waste materials drives acid mine drainage (AMD) and affects the global sulfur biogeochemical cycle. The generation of AMD is a complex

Hitchcock, Adam P.

14

Process for removing sulfur from sulfur-containing gases: high calcium fly-ash  

DOEpatents

The present disclosure relates to improved processes for treating hot sulfur-containing flue gas to remove sulfur therefrom. Processes in accordance with the present invention include preparing an aqueous slurry composed of a calcium alkali source and a source of reactive silica and/or alumina, heating the slurry to above-ambient temperatures for a period of time in order to facilitate the formation of sulfur-absorbing calcium silicates or aluminates, and treating the gas with the heat-treated slurry components. Examples disclosed herein demonstrate the utility of these processes in achieving improved sulfur-absorbing capabilities. Additionally, disclosure is provided which illustrates preferred configurations for employing the present processes both as a dry sorbent injection and for use in conjunction with a spray dryer and/or bagfilter. Retrofit application to existing systems is also addressed.

Rochelle, Gary T. (Austin, TX); Chang, John C. S. (Cary, NC)

1991-01-01

15

Hybrid Sulfur Thermochemical Process Development Annual Report  

SciTech Connect

The Hybrid Sulfur (HyS) Thermochemical Process is a means of producing hydrogen via water-splitting through a combination of chemical reactions and electrochemistry. Energy is supplied to the system as high temperature heat (approximately 900 C) and electricity. Advanced nuclear reactors (Generation IV) or central solar receivers can be the source of the primary energy. Large-scale hydrogen production based on this process could be a major contributor to meeting the needs of a hydrogen economy. This project's objectives include optimization of the HyS process design, analysis of technical issues and concerns, creation of a development plan, and laboratory-scale proof-of-concept testing. The key component of the HyS Process is the SO2-depolarized electrolyzer (SDE). Studies were performed that showed that an electrolyzer operating in the range of 500-600 mV per cell can lead to an overall HyS cycle efficiency in excess of 50%, which is superior to all other currently proposed thermochemical cycles. Economic analysis indicated hydrogen production costs of approximately $1.60 per kilogram for a mature nuclear hydrogen production plant. However, in order to meet commercialization goals, the electrolyzer should be capable of operating at high current density, have a long operating lifetime , and have an acceptable capital cost. The use of proton-exchange-membrane (PEM) technology, which leverages work for the development of PEM fuel cells, was selected as the most promising route to meeting these goals. The major accomplishments of this project were the design and construction of a suitable electrolyzer test facility and the proof-of-concept testing of a PEM-based SDE.

Summers, William A.; Buckner, Melvin R.

2005-07-21

16

Process for production of synthesis gas with reduced sulfur content  

DOEpatents

A process for the partial oxidation of a sulfur- and silicate-containing carbonaceous fuel to produce a synthesis gas with reduced sulfur content which comprises partially oxidizing said fuel at a temperature in the range of 1800.degree.-2200.degree. F. in the presence of a temperature moderator, an oxygen-containing gas and a sulfur capture additive which comprises an iron-containing compound portion and a sodium-containing compound portion to produce a synthesis gas comprising H.sub.2 and CO with a reduced sulfur content and a molten slag which comprises (i) a sulfur-containing sodium-iron silicate phase and (ii) a sodium-iron sulfide phase. The sulfur capture additive may optionally comprise a copper-containing compound portion.

Najjar, Mitri S. (Hopewell Junction, NY); Corbeels, Roger J. (Wappingers Falls, NY); Kokturk, Uygur (Wappingers Falls, NY)

1989-01-01

17

An early application of the Sulfur Cycle Hydrogen Production Process  

NASA Astrophysics Data System (ADS)

The electrochemical step of the Sulfur Cycle Hydrogen Production Process can be commercialized irrespective of the success or failure of activities in development of the high temperature thermochemical or heat source technologies. This version of the Sulfur Cycle, called the 'open-cycle', uses sulfur dioxide and water to produce two marketable products, i.e., hydrogen and sulfuric acid. An attractive application of the open-cycle has been identified in improving the gas cleanup systems for coal fired power plants. Analyses indicate that the revenues that could be realized by the power plant operator from the sale of hydrogen and sulfuric acid exceed the costs of owning and operating the Sulfur Cycle 'add-on' to the power plant.

Parker, G. H.; Farbman, G. H.; Summers, W. A.

18

Process for removing pyritic sulfur from bituminous coals  

DOEpatents

A process is provided for removing pyritic sulfur and lowering ash content of bituminous coals by grinding the feed coal, subjecting it to micro-agglomeration with a bridging liquid containing heavy oil, separating the microagglomerates and separating them to a water wash to remove suspended pyritic sulfur. In one embodiment the coal is subjected to a second micro-agglomeration step.

Pawlak, Wanda (Edmonton, CA); Janiak, Jerzy S. (Edmonton, CA); Turak, Ali A. (Edmonton, CA); Ignasiak, Boleslaw L. (Edmonton, CA)

1990-01-01

19

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This first quarter report of 2001 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf{trademark} (service mark of Gas Research Institute) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. During this reporting periods new catalyst formulations were tested. The experiments showed that the newest catalyst has slightly better performance, but catalyst TDA No.2 is still superior overall for use with the hybrid CrystaSulf process due to lower costs. Plans for catalyst pelletization and continued testing are described.

Girish Srinivas; Steven C. Gebhard; David W. DeBerry

2001-05-01

20

Membrane Separation Processes for the Benefit of the Sulfur-Iodine and Hybrid Sulfur Thermochemical Cycles  

SciTech Connect

Thermochemical cycles have been proposed as processes for the manufacture of hydrogen from water in which the only effluent is oxygen. In this paper, membrane-based technologies are described that have the promise of enabling the further development of thermochemical cycle processes. In direct service of the sulfur-iodine (S-I) cycle, membranes have been studied for the concentration of HI and sulfuric acid using pervaporation. In this work, Nafion® and SPEEK membranes have effectively concentrated both acids at temperatures as high as 134 ºC without any significant degradation. Measured fluxes of water and separation factors are commercially competitive and have been characterized with respect to acid concentration in the feed streams. Further, hydrogen permeability is discussed at 300 ºC with the goal of providing a method for the removal of the product gas from HI in the decomposition step, thus increasing the productiveness of the equilibrium limited reaction.

Christopher J. Orme; John R. Klaehn; Frederick F. Stewart

2009-05-01

21

Coal gasification: molten salt processes for sulfur emission control  

Microsoft Academic Search

Two molten salt desulfurization processes are illustrated. ; Precombustion desulfurization of coal takes place in a single vessel. Pulverized ; coal, slurried with molten salt, is allowed to react with a melt that contains an ; agent with an affinity for the sulfurous compounds. The coal collects at the ; top, being less dense than the melt, and is drawn

Glueck

1973-01-01

22

Nuclear Hydrogen Production Based on the Hybrid Sulfur Thermochemical Process  

SciTech Connect

Two Sulfur cycles - the Sulfur-Iodine (SI) and the Hybrid Sulfur (HyS) - have emerged as the leading thermochemical processes for making hydrogen using heat provided by advanced nuclear reactors. Numerous international efforts have been underway for several years to develop the SI cycle, but development of the HyS has lagged behind. Savannah River National Laboratory (SRNL) has been tasked by the U.S. Department of Energy Office of Nuclear Energy, Science and Technology with development of the HyS cycle since 2004. This paper discusses the background, current status, recent development results, and the future potential for the HyS process. Process design studies suggest that a net thermal efficiency of over 50% (higher heating value basis) is possible with HyS. Economic studies indicate that a nuclear hydrogen plant based on this process can be economically competitive, assuming that the sulfur dioxide-depolarized electrolyzer can be successfully developed. SRNL has demonstrated the use of a proton exchange membrane cell to perform this function, thus holding promise for economic and efficient hydrogen production. (authors)

Summers, William A.; Gorensek, Maximilian B. [Savannah River National Laboratory, 773-42A, Aiken, SC 29808 (United States)

2006-07-01

23

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This first quarter report of 2001 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of Gas Research Institute) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. During this reporting period tests were done to determine the effect of hydrocarbons such as n-hexane on catalyst performance with and without H{sub 2}S present. The experiments showed that hexane oxidation is suppressed when H{sub 2}S is present. Hexane represents the most reactive of the C1 to C6 series of alkanes. Since hexane exhibits low reactivity under H{sub 2}S oxidation conditions, and more importantly, does not change the SO{sub 2} selectivity, we can conclude that the C1-C6 hydrocarbons should not significantly interfere with the oxidation of H{sub 2}S into SO{sub 2}. Plans to determine the effect of aromatic compounds on catalyst performance for extended periods, and for catalyst pelletization and continued testing are described.

Girish Srinivas; Steven C. Gebhard; David W. DeBerry

2001-08-01

24

Performance and cost models for the direct sulfur recovery process. Task 1 Topical report, Volume 3  

SciTech Connect

The purpose of this project is to develop performance and cost models of the Direct Sulfur Recovery Process (DSRP). The DSRP is an emerging technology for sulfur recovery from advanced power generation technologies such as Integrated Gasification Combined Cycle (IGCC) systems. In IGCC systems, sulfur present in the coal is captured by gas cleanup technologies to avoid creating emissions of sulfur dioxide to the atmosphere. The sulfur that is separated from the coal gas stream must be collected. Leading options for dealing with the sulfur include byproduct recovery as either sulfur or sulfuric acid. Sulfur is a preferred byproduct, because it is easier to handle and therefore does not depend as strongly upon the location of potential customers as is the case for sulfuric acid. This report describes the need for new sulfur recovery technologies.

Frey, H.C. [North Carolina State Univ., Raleigh, NC (United States); Williams, R.B. [Carneigie Mellon Univ., Pittsburgh, PA (United States)

1995-09-01

25

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This final report describes the objectives, technical approach, results and conclusions for a project funded by the U.S. Department of Energy to test a hybrid sulfur recovery process for natural gas upgrading. The process concept is a configuration of CrystaTech, Inc.'s CrystaSulf{reg_sign} process which utilizes a direct oxidation catalyst upstream of the absorber tower to oxidize a portion of the inlet hydrogen sulfide (H{sub 2}S) to sulfur dioxide (SO{sub 2}) and elemental sulfur. This hybrid configuration of CrystaSulf has been named CrystaSulf-DO and represents a low-cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day and more. This hybrid process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both onshore and offshore applications. CrystaSulf is a nonaqueous sulfur recovery process that removes H{sub 2}S from gas streams and converts it to elemental sulfur. In CrystaSulf, H{sub 2}S in the inlet gas is reacted with SO{sub 2} to make elemental sulfur according to the liquid phase Claus reaction: 2H{sub 2}S + SO{sub 2} {yields} 2H{sub 2}O + 3S. The SO{sub 2} for the reaction can be supplied from external sources by purchasing liquid SO{sub 2} and injecting it into the CrystaSulf solution, or produced internally by converting a portion of the inlet gas H{sub 2}S to SO{sub 2} or by burning a portion of the sulfur produced to make SO{sub 2}. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, the needed SO{sub 2} is produced by placing a bed of direct oxidation catalyst in the inlet gas stream to oxidize a portion of the inlet H{sub 2}S. Oxidation catalysts may also produce some elemental sulfur under these conditions, which can be removed and recovered prior to the CrystaSulf absorber. The CrystaSulf-DO process can utilize direct oxidation catalyst from many sources. Numerous direct oxidation catalysts are available from many suppliers worldwide. They have been used for H{sub 2}S oxidation to sulfur and/or SO{sub 2} for decades. It was believed at the outset of the project that TDA Research, Inc., a subcontractor, could develop a direct oxidation catalyst that would offer advantages over other commercially available catalysts for this CrystaSulf-DO process application. This project involved the development of several of TDA's candidate proprietary direct oxidation catalysts through laboratory bench-scale testing. These catalysts were shown to be effective for conversion of H{sub 2}S to SO{sub 2} and to elemental sulfur under certain operating conditions. One of these catalysts was subsequently tested on a commercial gas stream in a bench-scale reactor at CrystaTech's pilot plant site in west Texas with good results. However, commercial developments have precluded the use of TDA catalysts in the CrystaSulf-DO process. Nonetheless, this project has advanced direct oxidation catalyst technology for H{sub 2}S control in energy industries and led to several viable paths to commercialization. TDA is commercializing the use of its direct oxidation catalyst technology in conjunction with the SulfaTreat{reg_sign} solid scavenger for natural gas applications and in conjunction with ConocoPhillips and DOE for gasification applications using ConocoPhillips gasification technology. CrystaTech is commercializing its CrystaSulf-DO process in conjunction with Gas Technology Institute for natural gas applications (using direct oxidation catalysts from other commercial sources) and in conjunction with ChevronTexaco and DOE for gasification applications using ChevronTexaco's gasification technology.

Dennis Dalrymple

2004-06-01

26

The Double Contact Process For Sulfuric Acid Production  

Microsoft Academic Search

In the usual contact plants 97-98% of the SO2 is oxidized to SO3 while the remaining 2-3% nonoxidized S02 are emitted. The stack gas generally contains 0.2-0.3% by volume SO2.Through changing to the Bayer Double Contact process, the conversion can be raised to 99.5% or higher. The sulfuric acid can be produced at the same cost as with the single

W. Moeller; K. Winkler

1968-01-01

27

A Development of Ceramics Cylinder Type Sulfuric Acid Decomposer for Thermo-Chemical Iodine-Sulfur Process Pilot Plant  

SciTech Connect

The hydrogen production method applying thermo-chemical Iodine-Sulfur process (IS process) which uses a nuclear high temperature gas cooled reactor is world widely greatly concerned from the view point of a combination as a clean method, free carbon dioxide in essence. In this process, it is essential a using ceramic material, especially SiC because a operation condition of this process is very corrosive due to a sulfuric acid atmosphere with high temperature and high pressure. In the IS process, a sulfuric acid decomposer is the key component which performs evaporating of sulfuric acid from liquid to gas and disassembling to SO{sub 2} gas. SiC was selected as ceramic material to apply for the sulfuric acid decomposer and a new type of binding material was also developed for SiC junction. This technology is expected to wide application not only for a sulfuric acid decomposer but also for various type components in this process. Process parameters were provided as design condition for the decomposer. The configuration of the sulfuric acid decomposer was studied, and a cylindrical tubes assembling type was selected. The advantage of this type is applicable for various type of components in the IS process due to manufacturing with using only simple shape part. A sulfuric acid decomposer was divided into two regions of the liquid and the gaseous phase of sulfuric acid. The thermal structural integrity analysis was studied for the liquid phase part. From the result of this analysis, it was investigated that the stress was below the strength of the breakdown probability 1/100,000 at any position, base material or junction part. The prototype model was manufactured, which was a ceramic portion in the liquid phase part, comparatively complicated configuration, of a sulfuric acid decomposer. The size of model was about 1.9 m in height, 1.0 m in width. Thirty-six cylinders including inlet and outlet nozzles were combined and each part article was joined using the new binder (slurry binder) and calcinated. Final polishing of the flange faces established in the entrance nozzles was also satisfactory. Many parts were joinable using new technology (new binder). For this reason, new technology is applicable to manufacture of not only a sulfuric acid decomposer but the instruments in the IS process, or other chemical processes. (authors)

Hiroshi Fukui; Isao Minatsuki [Mitsubishi Heavy Industries, LTD. (Japan); Kazuo Ishino [Pacific Rundum Co., Ltd. (Japan)

2006-07-01

28

Integrated Process Configuration for High-Temperature Sulfur Mitigation during Biomass Conversion via Indirect Gasification  

SciTech Connect

Sulfur present in biomass often causes catalyst deactivation during downstream operations after gasification. Early removal of sulfur from the syngas stream post-gasification is possible via process rearrangements and can be beneficial for maintaining a low-sulfur environment for all downstream operations. High-temperature sulfur sorbents have superior performance and capacity under drier syngas conditions. The reconfigured process discussed in this paper is comprised of indirect biomass gasification using dry recycled gas from downstream operations, which produces a drier syngas stream and, consequently, more-efficient sulfur removal at high temperatures using regenerable sorbents. A combination of experimental results from NREL's fluidizable Ni-based reforming catalyst, fluidizable Mn-based sulfur sorbent, and process modeling information show that using a coupled process of dry gasification with high-temperature sulfur removal can improve the performance of Ni-based reforming catalysts significantly.

Dutta. A.; Cheah, S.; Bain, R.; Feik, C.; Magrini-Bair, K.; Phillips, S.

2012-06-20

29

RECENT ADVANCES IN THE DEVELOPMENT OF THE HYBRID SULFUR PROCESS FOR HYDROGEN PRODUCTION  

SciTech Connect

Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process, which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. In the HyS Process, sulfur dioxide is oxidized in the presence of water at the electrolyzer anode to produce sulfuric acid and protons. The protons are transported through a cation-exchange membrane electrolyte to the cathode and are reduced to form hydrogen. In the second stage of the process, the sulfuric acid by-product from the electrolyzer is thermally decomposed at high temperature to produce sulfur dioxide and oxygen. The two gases are separated and the sulfur dioxide recycled to the electrolyzer for oxidation. The Savannah River National Laboratory (SRNL) has been exploring a fuel-cell design concept for the SDE using an anolyte feed comprised of concentrated sulfuric acid saturated with sulfur dioxide. The advantages of this design concept include high electrochemical efficiency and small footprint compared to a parallel-plate electrolyzer design. This paper will provide a summary of recent advances in the development of the SDE for the HyS process.

Hobbs, D.

2010-07-22

30

A Development of Ceramics Cylinder Type Sulfuric Acid Decomposer for ThermoChemical Iodine-Sulfur Process Pilot Plant  

Microsoft Academic Search

The hydrogen production method applying thermo-chemical Iodine-Sulfur process (IS process) which uses a nuclear high temperature gas cooled reactor is world widely greatly concerned from the view point of a combination as a clean method, free carbon dioxide in essence. In this process, it is essential a using ceramic material, especially SiC because a operation condition of this process is

Isao Minatsuki; Hiroshi Fukui; Kazuo Ishino

2007-01-01

31

A Development of Ceramics Cylinder Type Sulfuric Acid Decomposer for ThermoChemical Iodine-Sulfur Process Pilot Plant  

Microsoft Academic Search

The hydrogen production method applying thermo-chemical Iodine-Sulfur process (IS process) which uses a nuclear high temperature gas cooled reactor is world widely greatly concerned from the view point of a combination as a clean method, free carbon dioxide in essence. In this process, it is essential a using ceramic material, especially SiC because a operation condition of this process is

Hiroshi Fukui; Isao Minatsuki; Kazuo Ishino

2006-01-01

32

Discharge-charge process of the porous sulfur/carbon nanocomposite cathode for rechargeable lithium sulfur batteries  

NASA Astrophysics Data System (ADS)

The discharge-charge process of the porous sulfur/carbon nanocomposite cathode has been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), electrochemical impedance spectroscopy (EIS), and energy-dispersive X-ray spectroscopy (EDS). The results indicate that the porous nanocomposite enhances the electrolyte infiltrate into the cathode materials evenly, has a good capability of confining the soluble polysulfides and preventing the aggregation of insoluble Li2S. The regenerated elemental sulfur of the porous sulfur/carbon nanocomposite cathode exists in nano-size particles in the pore and the resistance decreases compared with the original cathode. Moreover, the porous nanocomposite realizes the micro-reactors during the discharge-charge process and can accommodate the volume change which is benefit for stabilization of the cathode during the electrochemical reaction.

Gao, Mengyao; Xiong, Xing; Wang, Weikun; Zhao, Shengrong; Li, Chengming; Zhang, Hao; Yu, Zhongbao; Huang, Yaqin

2014-02-01

33

A simple synthesis of hollow carbon nanofiber-sulfur composite via mixed-solvent process for lithium-sulfur batteries  

NASA Astrophysics Data System (ADS)

A hollow carbon nanofiber supported sulfur (HCNF-S) composite cathode material is prepared by a mixed-solvent (DMF/CS2) process in an organic solution for lithium-sulfur batteries. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations show the hollow structures of the HCNF and the homogeneous distribution of sulfur in the composite. The performance of the HCNF-S cathode is evaluated in lithium-sulfur batteries using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. It is found that the HCNF-S cathode shows perfect cycling stability. The results exhibit an initial discharge capacity of 1090 mAh g-1 and retains 600 mAh g-1 after 100 discharge/charge cycles at a high rate of 1 C. The excellent electrochemical properties benefit from the hollow and highly conductive network-like structure of HCNFs, which contribute to disperse sulfur and absorb polysulfides, and suppress the formation of residual Li2S layer.

Li, Qiang; Zhang, Zhian; Zhang, Kai; Fang, Jing; Lai, Yanqing; Li, Jie

2014-06-01

34

Investigation of the sulfur doping profile in femtosecond-laser processed silicon  

NASA Astrophysics Data System (ADS)

In this letter, we demonstrate that silicon can be doped with electrically active sulfur donors beyond the solubility limit of 3 × 1016 cm-3. We investigate the sulfur doping profile at the surface of femtosecond-laser processed silicon with secondary ion mass spectroscopy (SIMS) and capacitance-voltage measurements. SIMS confirms previous observations that the fs-laser process can lead to a sulfur hyperdoping of 5×1019 cm-3 at the surface. Nevertheless, the electrical measurements show that less than 1% of the sulfur is electrically active as a donor.

Guenther, Kay-Michael; Gimpel, Thomas; Kontermann, Stefan; Schade, Wolfgang

2013-05-01

35

Sodium--sulfur battery and process for its production  

Microsoft Academic Search

A rechargeable galvanic battery contains liquid sodium as the negative electrochemically active material, liquid sulfur as the positive electrochemically active material, and a ceramic solid electrolyte which is capable of conducting sodium ions. The sodium is completely absorbed in a fine-pored metal felt or mat. The sulfur is completely absorbed in a graphite felt or mat. The metal felt has

W. Baukal; R. Knodler; W. H. Kuhn

1977-01-01

36

Slipstream testing of the Direct Sulfur Recovery Process  

SciTech Connect

The objective of this work is to continue further development of the zinc titanate fluidized-bed desulfurization (ZTFBD) and the Direct Sulfur Recovery Process (DSRP) technologies for hot gas cleanup in integrated gasification combined cycle (IGCC) power generating systems. There are three main goals of this project: development of an integrated, skid-mounted, bench-scale ZTFBD/DSRP reactor system; testing the integrated system over an extended period with a slipstream of coal gas from an operating gasifier to quantify the degradation in performance, if any, caused by the trace contaminants present in coal gas (including heavy metals, chlorides, fluorides, and ammonia); and design, fabrication, and commissioning of a larger, pilot-plant scale DSRP reactor system capable of operating on a six-fold volume of gas greater than the reactors used in the bench-scale field tests. The results so far on the first phase are limited to design and construction of the test apparatus. This report describes DSRP technology and equipment that will be used to test it.

Gangwal, S.K.; Portzer, J.W.; Howe, G.B. [Research Triangle Inst., Research Triangle Park, NC (United States); Chen, D.H. [Lamar Univ., Beaumont, TX (United States); McMillian, M.H. [USDOE Morgantown Energy Technology Center, WV (United States)

1994-10-01

37

SUMMARY REPORT: SULFUR OXIDES CONTROL TECHNOLOGY SERIES: FLUE GAS DESULFURIZATION - SPRAY DRYER PROCESS  

EPA Science Inventory

Described spray dryer flue gas desulfurization (FGD), which is a throwaway process in which sulfur dioxide (SO2) is removed from flue gas by an atomized lime slurry [Ca(OH)2]. he hot flue gas dries the droplets to form a dry waste product, while the absorbent reacts with sulfur d...

38

Process for purifying a sulfur dioxide containing gas by washing with an ammonia aqueous solution  

Microsoft Academic Search

Process for purifying a sulfur dioxide containing gas, by washing with an ammonia aqueous solution is comprised of the following steps: (a) contacting a sulfur dioxide containing gas with ammonia and\\/or ammonium sulfite in the presence of water, to form a solution containing ammonium bisulfite and\\/or sulfite; (b) reacting at least a portion of the solution obtained in step (a)

A. Deschamps; S. Franckowiak; P. Renault

1979-01-01

39

Wednesday, March 25, 2009 SULFUR ON MARS: ROCKS, SOILS, AND CYCLING PROCESSES  

E-print Network

and the Sulfur Cycle on Mars [#2152] Elevated S in martian mantle/crust and absence of plate tectonics resultsWednesday, March 25, 2009 SULFUR ON MARS: ROCKS, SOILS, AND CYCLING PROCESSES 1:30 p.m. Waterway in a S-enriched sedimentary mass. The S-cycle of Mars is analogous to the Earth's C-cycle, with long

Rathbun, Julie A.

40

Preparation of sulfurized powdered activated carbon from waste tires using an innovative compositive impregnation process.  

PubMed

The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na2S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m2/g and the S content of 2.61% by mass were obtained at 900 degrees C and at the S feed ratio of 2160 mg Na2S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased. PMID:15303299

Yuan, Chung-Shin; Lin, Hsun-Yu; Wu, Chun-Hsin; Liu, Ming-Han; Hung, Chung-Hsuang

2004-07-01

41

Development status of electrolysis technology for the sulfur cycle hydrogen production process  

NASA Astrophysics Data System (ADS)

The Sulfur Cycle Hydrogen Production Process comprises an electrochemical and a thermochemical reaction. In an electrolysis cell, sulfur dioxide dissolved in aqueous solutions is electrochemically oxidized to sulfuric acid at the anode, while hydrogen gas is evolved at the cathode. By use of thermal energy from a high-temperature heat source, sulfuric acid produced in the electrolyzer is vaporized and catalytically decomposed to form sulfur dioxide, water and oxygen. Four approaches for improving electrolysis technology are considered, including an electrochemical study of catalysts, the development of electrode fabrication processes, the optimization of cell configuration, and the selection and investigation of separator materials. Palladium and palladium oxide were found to be superior to platinum as electrocatalysts for SO2 oxidation.

Lu, P. W. T.; Ammon, R. L.

42

Sulfur tolerant molten carbonate fuel cell anode and process  

DOEpatents

Molten carbonate fuel cell anodes incorporating a sulfur tolerant carbon monoxide to hydrogen water-gas-shift catalyst provide in situ conversion of carbon monoxide to hydrogen for improved fuel cell operation using fuel gas mixtures of over about 10 volume percent carbon monoxide and up to about 10 ppm hydrogen sulfide.

Remick, Robert J. (Naperville, IL)

1990-01-01

43

HYBRID SULFUR PROCESS REFERENCE DESIGN AND COST ANALYSIS  

SciTech Connect

This report documents a detailed study to determine the expected efficiency and product costs for producing hydrogen via water-splitting using energy from an advanced nuclear reactor. It was determined that the overall efficiency from nuclear heat to hydrogen is high, and the cost of hydrogen is competitive under a high energy cost scenario. It would require over 40% more nuclear energy to generate an equivalent amount of hydrogen using conventional water-cooled nuclear reactors combined with water electrolysis compared to the proposed plant design described herein. There is a great deal of interest worldwide in reducing dependence on fossil fuels, while also minimizing the impact of the energy sector on global climate change. One potential opportunity to contribute to this effort is to replace the use of fossil fuels for hydrogen production by the use of water-splitting powered by nuclear energy. Hydrogen production is required for fertilizer (e.g. ammonia) production, oil refining, synfuels production, and other important industrial applications. It is typically produced by reacting natural gas, naphtha or coal with steam, which consumes significant amounts of energy and produces carbon dioxide as a byproduct. In the future, hydrogen could also be used as a transportation fuel, replacing petroleum. New processes are being developed that would permit hydrogen to be produced from water using only heat or a combination of heat and electricity produced by advanced, high temperature nuclear reactors. The U.S. Department of Energy (DOE) is developing these processes under a program known as the Nuclear Hydrogen Initiative (NHI). The Republic of South Africa (RSA) also is interested in developing advanced high temperature nuclear reactors and related chemical processes that could produce hydrogen fuel via water-splitting. This report focuses on the analysis of a nuclear hydrogen production system that combines the Pebble Bed Modular Reactor (PBMR), under development by PBMR (Pty.) Ltd. in the RSA, with the Hybrid Sulfur (HyS) Process, under development by the Savannah River National Laboratory (SRNL) in the US as part of the NHI. This work was performed by SRNL, Westinghouse Electric Company, Shaw, PBMR (Pty) Ltd., and Technology Insights under a Technical Consulting Agreement (TCA). Westinghouse Electric, serving as the lead for the PBMR process heat application team, established a cost-shared TCA with SRNL to prepare an updated HyS thermochemical water-splitting process flowsheet, a nuclear hydrogen plant preconceptual design and a cost estimate, including the cost of hydrogen production. SRNL was funded by DOE under the NHI program, and the Westinghouse team was self-funded. The results of this work are presented in this Final Report. Appendices have been attached to provide a detailed source of information in order to document the work under the TCA contract.

Gorensek, M.; Summers, W.; Boltrunis, C.; Lahoda, E.; Allen, D.; Greyvenstein, R.

2009-05-12

44

Initial design of a dilute sulfuric acid pretreatment process for aspen wood chips  

Microsoft Academic Search

A preliminary process design for dilute sulfuric acid pretreatment of aspen wood chips in order to obtain fermentable sugars\\u000a has been prepared and subjected to an economic evaluation. The process design was prepared according to experimental data\\u000a on the kinetics of dilute sulfuric acid prehydrolysis and particle size effects obtained in this study and our previous work.\\u000a The initial economic

R. Torget; M. Himmel; J. D. Wright; K. Grohmann

1988-01-01

45

Process for recovery of sulfur from acid gases  

DOEpatents

Elemental sulfur is recovered from the H.sub.2 S present in gases derived from fossil fuels by heating the H.sub.2 S with CO.sub.2 in a high-temperature reactor in the presence of a catalyst selected as one which enhances the thermal dissociation of H.sub.2 S to H.sub.2 and S.sub.2. The equilibrium of the thermal decomposition of H.sub.2 S is shifted by the equilibration of the water-gas-shift reaction so as to favor elemental sulfur formation. The primary products of the overall reaction are S.sub.2, CO, H.sub.2 and H.sub.2 O. Small amounts of COS, SO.sub.2 and CS.sub.2 may also form. Rapid quenching of the reaction mixture results in a substantial increase in the efficiency of the conversion of H.sub.2 S to elemental sulfur. Plant economy is further advanced by treating the product gases to remove byproduct carbonyl sulfide by hydrolysis, which converts the COS back to CO.sub.2 and H.sub.2 S. Unreacted CO.sub.2 and H.sub.2 S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H.sub.2 and CO, which has value either as a fuel or as a chemical feedstock and recovers the hydrogen value from the H.sub.2 S.

Towler, Gavin P. (Kirkbymoorside, GB2); Lynn, Scott (Pleasant Hill, CA)

1995-01-01

46

Electrochemistry of inorganic sulfur compounds and electroanalytical methods for synfuel process streams  

SciTech Connect

Electrode reactions of the following oxidation states of sulfur were investigated by differential pulse voltammetry (DPV): +4(SO/sub 2/, SO/sub 3/=), +2.5(S/sub 4/O/sub 6/=), +2(S/sub 2/O/sub 3/=), zero (elemental sulfur and the polysulfidic component of S/sub x/=). Sensitive, selective, precise and accurate DPV methods were developed for the quantitative speciation of sulfur. Indicator electrodes included glassy carbon anodes in Levich's rotated disk configuration and dropping mercury anodes and cathodes. The speciation of aqueous synfuel process streams revealed that liquefaction technologies produced relatively higher concentrations of sulfur contaminants in the oxidation states -2 and 0, while gasification processes yielded comparably more S(+2) and S(+4). Electrooxidation of tetrathionate to sulfate was conclusively substantiated.

Ankabrandt, S.J.

1981-01-01

47

Overview of nuclear hydrogen production research through iodine sulfur process at INET  

Microsoft Academic Search

Thermochemical water-splitting cycle is a promising process to produce hydrogen using solar or nuclear energy. R&D on hydrogen production through iodine sulfur (IS) thermochemical cycle was initiated in 2005 at INET. Fundamental studies on the three reactions of IS cycle, i.e., Bunsen reaction, HI decomposition reaction, sulfuric acid decomposition reaction, and related techniques, such as separation, concentration and purification, were

P. Zhang; S. Z. Chen; L. J. Wang; J. M. Xu

2010-01-01

48

Sulfur Iodine Process Summary for the Hydrogen Technology Down-Selection: Process Performance Package  

SciTech Connect

This document describes the details of implementing a Sulfur-Iodine (S-I) hydrogen production plant to deploy with the Next General Nuclear Power Plant (NGNP). Technical requirements and specifications are included, and a conceptual plant design is presented. The following areas of interest are outlined in particular as a baseline for the various technology comparisons: (1) Performance Criteria - (a) Quantity of hydrogen produced, (b) Purity of hydrogen produced, (c) Flexibility to serve various applications, (d) Waste management; (2) Economic Considerations - (a) Cost of hydrogen, (b) Development costs; and (3) Risk - (a) Technical maturity of the S-I process, (b) Development risk, (c) Scale up options.

Benjamin Russ

2009-06-01

49

Sulfur oxides control technology series: Flue gas desulfurization. WellmanLord process. Summary report  

Microsoft Academic Search

The Wellman-Lord flue gas desulfurization (FGD) process, is being studied by the Environmental Protection Agency (EPA) as part of and extensive program of technology development in the area of flue gas desulfurization. In this regenerable process, sulfur dioxide (SO2) is removed from flue gases with a sodium sulfite scrubbing solution. The concentrated SO2 stream that is produced can be processed

C. E. Hudak; J. M. Burke

1979-01-01

50

Process and apparatus for generating elemental sulfur and re-usable metal oxide from spent metal sulfide sorbents  

DOEpatents

A process and apparatus for generating elemental sulfur and re-usable metal oxide from spent metal-sulfur compound. Spent metal-sulfur compound is regenerated to re-usable metal oxide by moving a bed of spent metal-sulfur compound progressively through a single regeneration vessel having a first and second regeneration stage and a third cooling and purging stage. The regeneration is carried out and elemental sulfur is generated in the first stage by introducing a first gas of sulfur dioxide which contains oxygen at a concentration less than the stoichiometric amount required for complete oxidation of the spent metal-sulfur compound. A second gas containing sulfur dioxide and excess oxygen at a concentration sufficient for complete oxidation of the partially spent metal-sulfur compound, is introduced into the second regeneration stage. Gaseous sulfur formed in the first regeneration stage is removed prior to introducing the second gas into the second regeneration stage. An oxygen-containing gas is introduced into the third cooling and purging stage. Except for the gaseous sulfur removed from the first stage, the combined gases derived from the regeneration stages which are generally rich in sulfur dioxide and lean in oxygen, are removed from the regenerator as an off-gas and recycled as the first and second gas into the regenerator. Oxygen concentration is controlled by adding air, oxygen-enriched air or pure oxygen to the recycled off-gas.

Ayala, Raul E. (Clifton Park, NY); Gal, Eli (Lititz, PA)

1995-01-01

51

Catalytic hydrosolvation process converts coal to low-sulfur liquid fuel  

NASA Technical Reports Server (NTRS)

Development of the catalytic hydrosolvation process for converting coal to low-sulfur fuel oil is described in this paper. Coal impregnated with catalyst was slurried with oil, and the mixture was hydrogenated at a temperature of 475 C, and 30 min residence time under 3600 psi pressure. A ton of coal yielded 3.5 bbl of fuel oil containing 0.2% sulfur, with naphtha and C1-C4 hydrocarbon gases as byproducts. A preliminary economic evaluation of the process indicated potential for further development.

Qader, S. A.

1978-01-01

52

Sulfur Iodine Process Summary for the Hydrogen Technology Down-Selection  

SciTech Connect

This report summarizes the sulfur-iodine (SI) thermochemical water splitting process for the purpose of supporting the process for evaluating and recommending a hydrogen production technology to deploy with the Next Generation Nuclear Plant (NGNP). This package provides the baseline process description as well as a comparison with the process as it was implemented in the Integrated Lab Scale (ILS) experiment conducted at General Atomics from 2006-2009.

Benjamin Russ

2009-05-01

53

DEVELOPMENT OF INFRARED METHODS FOR CHARACTERIZATION OF INORGANIC SULFUR SPECIES RELATED TO INJECTION DESULFURIZATION PROCESSES  

EPA Science Inventory

Current methods designed to control and reduce the amount of sulfur dioxide emitted into the atmosphere from coal-fired power plants and factories rely upon the reaction between SO2 and alkaline earth compounds and are called flue gas desulfurization (FGD) processes. Of these met...

54

Configuring the thermochemical hydrogen sulfuric acid process step for the Tandem Mirror reactor  

NASA Astrophysics Data System (ADS)

The sulfuric acid step was identified as the critical part of the thermochemical cycle in dictating the thermal demands and temperature requirements of the heat source. The general atomic sulfur-iodine cycle was coupled to a tandem mirror. The sulfuric acid decomposition process step was focused on specifically since this step can use the high efficiency electrical power of the direct converter together with the other thermal-produced electricity to Joule-heat a noncatalytic SO3 decomposer to approximately 1250 K. The blanket temperature was lowered to about 900 K, greatly alleviating materials problems, the level of technology required safety problems, and costs. A moderate degree of heat was integrated to keep the cycle efficiency around 48%, but the number of heat exchangers was limited in order to keep hydrogen production costs within reasonable bounds.

Galloway, T. R.

1981-05-01

55

Configuring the thermochemical hydrogen sulfuric acid process step for the Tandem Mirror Reactor  

SciTech Connect

This paper identifies the sulfuric acid step as the critical part of the thermochemical cycle in dictating the thermal demands and temperature requirements of the heat source. The General Atomic Sulfur-Iodine Cycle is coupled to a Tandem Mirror. The sulfuric acid decomposition process step is focused on specifically since this step can use the high efficiency electrical power of the direct converter together with the other thermal-produced electricity to Joule-heat a non-catalytic SO/sub 3/ decomposer to approximately 1250/sup 0/K. This approach uses concepts originally suggested by Dick Werner and Oscar Krikorian. The blanket temperature can be lowered to about 900/sup 0/K, greatly alleviating materials problems, the level of technology required, safety problems, and costs. A moderate degree of heat has been integrated to keep the cycle efficiency around 48%, but the number of heat exchangers has been limited in order to keep hydrogen production costs within reasonable bounds.

Galloway, T.R.

1981-05-01

56

Developing an energy efficient steam reforming process to produce hydrogen from sulfur-containing fuels  

NASA Astrophysics Data System (ADS)

Hydrogen powered fuel cells have the potential to produce electricity with higher efficiency and lower emissions than conventional combustion technology. In order to realize the benefits of a hydrogen fuel cell an efficient method to produce hydrogen is needed. Currently, over 90% of hydrogen is produced from the steam reforming of natural gas. However, for many applications including fuel cell vehicles, the use of a liquid fuel rather than natural gas is desirable. This work investigates the feasibility of producing hydrogen efficiently by steam reforming E85 (85% ethanol/15% gasoline), a commercially available sulfur-containing transportation fuel. A Rh-Pt/SiO2-ZrO2 catalyst has demonstrated good activity for the E85 steam reforming reaction. An industrial steam reforming process is often run less efficiently, with more water and at higher temperatures, in order to prevent catalyst deactivation. Therefore, it is desirable to develop a process that can operate without catalyst deactivation at more energy efficient conditions. In this study, the steam reforming of a sulfur-containing fuel (E85) was studied at near stoichiometric steam/carbon ratios and at 650C, conditions at which catalyst deactivation is normally measured. At these conditions the catalyst was found to be stable steam reforming a sulfur-free E85. However, the addition of low concentrations of sulfur significantly deactivated the catalyst. The presence of sulfur in the fuel caused catalyst deactivation by promoting ethylene which generates surface carbon species (coke) that mask catalytic sites. The amount of coke increased during time on stream and became increasingly graphitic. However, the deactivation due to both sulfur adsorption and coke formation was reversible with air treatment at 650°C. However, regenerations were found to reduce the catalyst life. Air regenerations produce exotherms on the catalyst surface that cause structural changes to the catalyst. During regenerations the accessibility of the precious metal particles is reduced which causes the catalyst to deactivate more rapidly during subsequent steam reforming cycles. Changes to the carrier morphology also occur at these conditions. Regenerating the catalyst before significant deactivation is measured can improve the stability of the catalyst. Thus a process with preemptive controlled air regenerations is proposed in order to run a steam reforming process with sulfur containing fuels.

Simson, Amanda

57

A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process for decentralized wastewater treatment.  

PubMed

Nitrogen discharges from decentralized wastewater treatment (DWT) systems contribute to surface and groundwater contamination. However, the high variability in loading rates, long idle periods and lack of regular maintenance presents a challenge for biological nitrogen removal in DWT. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process was developed that combines nitrate (NO3(-)) adsorption to scrap tire chips with sulfur-oxidizing denitrification. This allows the tire chips to adsorb NO3(-) when the influent loading exceeds the denitrification capacity of the biofilm and release it when NO3(-) loading rates are low (e.g. at night). Three waste products, scrap tire chips, elemental sulfur pellets and crushed oyster shells, were used as a medium in adsorption, leaching, microcosm and up-flow packed bed bioreactor studies of NO3(-) removal from synthetic nitrified DWT wastewater. Adsorption isotherms showed that scrap tire chips have an adsorption capacity of 0.66 g NO3(-)-N kg(-1) of scrap tires. Leaching and microcosm studies showed that scrap tires leach bioavailable organic carbon that can support mixotrophic metabolism, resulting in lower effluent SO4(2-) concentrations than sulfur oxidizing denitrification alone. In column studies, the T-SHAD process achieved high NO3(-)-N removal efficiencies under steady state (90%), variable flow (89%) and variable concentration (94%) conditions. PMID:24922353

Krayzelova, Lucie; Lynn, Thomas J; Banihani, Qais; Bartacek, Jan; Jenicek, Pavel; Ergas, Sarina J

2014-09-15

58

Oxygen and sulfur isotopes insights into ongoing biogeochemical processes in sediments from the Argentine Basin  

NASA Astrophysics Data System (ADS)

The Argentine Basin is characterized by dynamic depositional conditions, such as high sedimentation rates and gravity mass flows, where reactive iron and manganese mineral phases are rapidly buried. Sulfate pore water concentration profiles in this area reflect these variable depositional conditions. Interpretation of these patterns led to the conclusion that sulfate concentration profiles are controlled by methane fluxes, mass flows, diffusion or any combination of these processes (Hensen et al., 2003). Sulfur and oxygen isotope data of pore water sulfate provide additional constraints on the interpretation of sulfate concentration patterns and allow us to gain insight into ongoing biogeochemical processes in the sediment column. Samples were collected aboard the RV Meteor during a recent cruise to the Argentine Basin area (May-July 2009). We present concentration profiles of pore water sulfate and sulfide from several study sites in the Argentine Basin. We can identify three classifications of sulfate concentration profiles: Linear, Kink, and Concave Up (Hensen et al., 2003). We compare these profiles to the isotopic composition of oxygen and sulfur of sulfate and sulfur isotopic composition of sulfide. This allows us to identify zones with ongoing biogeochemical sulfur cycling. Based of sulfate isotope studies three primary observations can be made for our study sites: 1)oxygen isotopic composition of sulfate consistently plateaus near a value of 25‰, this is 4‰ lighter than expected if the sulfate is in equilibrium with normal seawater, 2)while oxygen isotopic composition approaches a constant value, the isotopic compositiion of sulfur continues to increase, indicative of ongoing sulfate reduction, 3)sulfate isotope cross plots from linear-type sulfate concentration profiles yield additional information about underlying processes contributing to the sulfate distribution within the sediment column. Hensen, C. et al. (2003) Geochimica et Cosmochimica Acta, 67, 2631-2647.

Arnold, G.; Riedinger, N.; Sawicka, J.; Formolo, M.; Brunner, B.

2009-12-01

59

Process for sequestering carbon dioxide and sulfur dioxide  

DOEpatents

A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Maroto-Valer, M. Mercedes (State College, PA); Zhang, Yinzhi (State College, PA); Kuchta, Matthew E. (State College, PA); Andresen, John M. (State College, PA); Fauth, Dan J. (Pittsburgh, PA)

2009-10-20

60

[Effects of different processing methods on effective components and sulfur dioxide residue in Gastrodiae Rhizoma].  

PubMed

The contents of adenosine, gastrodin, 4-hydroxybenzyl alcohol, 4-hydroxybenzaldehyde, parishin and sulfur dioxide residue were compared in differently-processed Gastrodiae Rhizoma to provide the basis for a reasonable processing method of Gastrodiae Rhizoma. The analysis was performed on a Merck Purospher STAR column (4.6 mm x 250 mm, 5 ?m) with a mobile phase consisting of methanol and water (containing 0.1% formic acid) under gradient elution at a flow rate of 1.0 mL x min(-1). The eluates were detected at 270 nm, and the column temperature was 35°C. The content of adenosin, gastrodin, 4-hydroxybenzyl alcohol, 4-hydroxy-benzaldehyde and parishin in processing of boiling or sulfur-fumigated were lower than that of in processing of steaming. Furthermore, the sulfur dioxide residue of sulphur-fumigated groups exceed 400 mg x kg(-1). This stable and reliable method will contribute to the quality control of different processed Gastrodiae Rhizoma. PMID:25507536

Ning, Zi-Wan; Mao, Chun-Qin; Lu, Tu-Lin; Ji, De; Liu, Jing; Ji, Lin; Yang, Huan; Wang, Fa-Qin

2014-08-01

61

[Effects of different processing methods on effective components and sulfur dioxide residue in Gastrodiae Rhizoma].  

PubMed

The contents of adenosine, gastrodin, 4-hydroxybenzyl alcohol, 4-hydroxybenzaldehyde, parishin and sulfur dioxide residue were compared in differently-processed Gastrodiae Rhizoma to provide the basis for a reasonable processing method of Gastrodiae Rhizoma. The analysis was performed on a Merck Purospher STAR column (4.6 mm x 250 mm, 5 ?m) with a mobile phase consisting of methanol and water (containing 0.1% formic acid) under gradient elution at a flow rate of 1.0 mL x min(-1). The eluates were detected at 270 nm, and the column temperature was 35°C. The content of adenosin, gastrodin, 4-hydroxybenzyl alcohol, 4-hydroxy-benzaldehyde and parishin in processing of boiling or sulfur-fumigated were lower than that of in processing of steaming. Furthermore, the sulfur dioxide residue of sulphur-fumigated groups exceed 400 mg x kg(-1). This stable and reliable method will contribute to the quality control of different processed Gastrodiae Rhizoma. PMID:25423814

Ning, Zi-Wan; Mao, Chun-Qin; Lu, Tu-Lin; Ji, De; Liu, Jing; Ji, Lin; Yang, Huan; Wang, Fa-Qin

2014-08-01

62

Global warming potential of the sulfur–iodine process using life cycle assessment methodology  

Microsoft Academic Search

A life cycle assessment (LCA) of one proposed method of hydrogen production – thermochemical water-splitting using the sulfur–iodine cycle couple with a very high-temperature nuclear reactor – is presented in this paper. Thermochemical water-splitting theoretically offers a higher overall efficiency than high-temperature electrolysis of water because heat from the nuclear reactor is provided directly to the hydrogen generation process, instead

William C. Lattin; Vivek P. Utgikar

2009-01-01

63

Process sensitivity studies of the Westinghouse sulfur cycle for hydrogen generation  

NASA Technical Reports Server (NTRS)

The effect of variations of acid concentration, pressure, and temperature on the thermal process efficiency of the Westinghouse sulfur cycle was examined using the HYDRGN program. Modifications to the original program were made to duplicate the process flowsheet and take into account combined cycle heat-to-work efficiencies for electrochemical work requirements, aqueous solutions, and heat-of-mixing effects. A total of 125 process variations were considered (acid concentration: 50-90 w/o; pressure: 15-750 psia; temperature: 922K - 1366K). The methods of analysis, results, and conclusions are presented.

Carty, R. H.; Cox, K. E.; Funk, J. E.; Soliman, M. A.; Conger, W. L.; Brecher, L. E.; Spewock, S.

1976-01-01

64

Sulfuric acid on Europa and the radiolytic sulfur cycle  

NASA Technical Reports Server (NTRS)

A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continuously cycles sulfur between three forms: sulfuric acid, sulfur dioxide, and sulfur polymers, with sulfuric acid being about 50 times as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that low-temperature, liquid sulfuric acid may influence geological processes.

Carlson, R. W.; Johnson, R. E.; Anderson, M. S.

1999-01-01

65

THE EFFECT OF SULFUR ON METHANE PARTIAL OXIDATION AND REFORMING PROCESSES FOR LEAN NOX TRAP CATALYSIS  

SciTech Connect

Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by >90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as "regeneration" since the catalyst is reactivated for more NOx trapping after NOx purge. Creating the rich exhaust conditions for regeneration can be accomplished by catalytic partial oxidation of methane in the exhaust system. Furthermore, catalytic reforming of partial oxidation exhaust can enable increased quantities of H2 which is an excellent reductant for lean NOx trap regeneration. It is critical to maintain clean and efficient partial oxidation and reforming processes to keep the lean NOx trap functioning properly and to reduce extra fuel consumption from the regeneration process. Although most exhaust constituents do not impede partial oxidation and reforming, some exhaust constituents may negatively affect the catalysts and result in loss of catalytic efficiency. Of particular concern are common catalyst poisons sulfur, zinc, and phosphorous. These poisons form in the exhaust through combustion of fuel and oil, and although they are present at low concentrations, they can accumulate to significant levels over the life of an engine system. In the work presented here, the effects of sulfur on the partial oxidation and reforming catalytic processes were studied to determine any durability limitations on the production of reductants for lean NOx trap catalyst regeneration.

Parks, II, James E [ORNL; Ponnusamy, Senthil [ORNL

2006-01-01

66

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, October-December 1982  

SciTech Connect

The general objective is to develop dependable and accurate instrumental analysis methods for the determination of sulfur moieties. These will include polysulfides, dithionite and polythionates. Calorimetric procedures (thermometric titrations, injection enthalpimetry) and electroanalytical techniques (voltammetry, coulometric analysis, etc.) will be used. The complete speciation of sulfur will be undertaken in representative synfuel process stream samples. Total sulfidic sulfur has been quantitated with the aid of diffusion currents engendered by the anodic depolarization of the dropping mercury electrode. Classical chemical reactions involving polythionates were surveyed as to their applicability to analytical determinations by Direct Injection Enthalpimetry (DIE). Reactions included polythionate decomposition by sulfide precipitation with mercuric chloride, silver nitrate, and thallows nitrate; polythionate oxidation, cyanolysis, and complexation with aquopentaammine cobalt (+3) chloride. An analysis of two H-Coal sour water samples was undertaken using thermochemical, electrochemical and classical methods. The various methods yielded consistent sulfidic and polysulfidic sulfur levels. This internal consistency substantiated the accuracy of the findings.

Jordan, J.; Stahl, J.; Yakupkovic, J.

1983-01-01

67

Pretreatment of rice straw with combined process using dilute sulfuric acid and aqueous ammonia  

PubMed Central

Background Use of lignocellulosic biomass has received attention lately because it can be converted into various versatile chemical compounds by biological processes. In this study, a two-step pretreatment with dilute sulfuric acid and aqueous ammonia was performed efficiently on rice straw to obtain fermentable sugar. The soaking in aqueous ammonia process was also optimized by a statistical method. Results Response surface methodology was employed. The determination coefficient (R2) value was found to be 0.9607 and the coefficient of variance was 6.77. The optimal pretreatment conditions were a temperature of 42.75°C, an aqueous ammonia concentration of 20.93%, and a reaction time of 48 h. The optimal enzyme concentration for saccharification was 30 filter paper units. The crystallinity index was approximately 60.23% and the Fourier transform infrared results showed the distinct peaks of glucan. Ethanol production using Saccharomyces cerevisiae K35 was performed to verify whether the glucose saccharified from rice straw was fermentable. Conclusions The combined pretreatment using dilute sulfuric acid and aqueous ammonia on rice straw efficiently yielded fermentable sugar and achieved almost the same crystallinity index as that of ?-cellulose. PMID:23898802

2013-01-01

68

Regenerative process and system for the simultaneous removal of particulates and the oxides of sulfur and nitrogen from a gas stream  

DOEpatents

A process and system for simultaneously removing from a gaseous mixture, sulfur oxides by means of a solid sulfur oxide acceptor on a porous carrier, nitrogen oxides by means of ammonia gas and particulate matter by means of filtration and for the regeneration of loaded solid sulfur oxide acceptor. Finely-divided solid sulfur oxide acceptor is entrained in a gaseous mixture to deplete sulfur oxides from the gaseous mixture, the finely-divided solid sulfur oxide acceptor being dispersed on a porous carrier material having a particle size up to about 200 microns. In the process, the gaseous mixture is optionally pre-filtered to remove particulate matter and thereafter finely-divided solid sulfur oxide acceptor is injected into the gaseous The government of the United States of America has rights in this invention pursuant to Contract No. DE-AC21-88MC 23174 awarded by the U.S. Department of Energy.

Cohen, Mitchell R. (Troy, NY); Gal, Eli (Lititz, PA)

1993-01-01

69

Production, preservation, and biological processing of mass-independent sulfur isotope fractionation in the Archean surface environment.  

PubMed

Mass-independent fractionation of sulfur isotopes (S MIF) in Archean and Paleoproterozoic rocks provides strong evidence for an anoxic atmosphere before ~2,400 Ma. However, the origin of this isotopic anomaly remains unclear, as does the identity of the molecules that carried it from the atmosphere to Earth's surface. Irrespective of the origin of S MIF, processes in the biogeochemical sulfur cycle modify the primary signal and strongly influence the S MIF preserved and observed in the geological record. Here, a detailed model of the marine sulfur cycle is used to propagate and distribute atmospherically derived S MIF from its delivery to the ocean to its preservation in the sediment. Bulk pyrite in most sediments carries weak S MIF because of microbial reduction of most sulfur compounds to form isotopically homogeneous sulfide. Locally, differential incorporation of sulfur compounds into pyrite leads to preservation of S MIF, which is predicted to be most highly variable in nonmarine and shallow-water settings. The Archean ocean is efficient in diluting primary atmospheric S MIF in the marine pools of sulfate and elemental sulfur with inputs from SO2 and H2S, respectively. Preservation of S MIF with the observed range of magnitudes requires the S MIF production mechanism to be moderately fractionating ( 20-40‰). Constraints from the marine sulfur cycle allow that either elemental sulfur or organosulfur compounds (or both) carried S MIF to the surface, with opposite sign to S MIF in SO2 and H2SO4. Optimal progress requires observations from nonmarine and shallow-water environments and experimental constraints on the reaction of photoexcited SO2 with atmospheric hydrocarbons. PMID:23572589

Halevy, Itay

2013-10-29

70

Production, preservation, and biological processing of mass-independent sulfur isotope fractionation in the Archean surface environment  

PubMed Central

Mass-independent fractionation of sulfur isotopes (S MIF) in Archean and Paleoproterozoic rocks provides strong evidence for an anoxic atmosphere before ?2,400 Ma. However, the origin of this isotopic anomaly remains unclear, as does the identity of the molecules that carried it from the atmosphere to Earth’s surface. Irrespective of the origin of S MIF, processes in the biogeochemical sulfur cycle modify the primary signal and strongly influence the S MIF preserved and observed in the geological record. Here, a detailed model of the marine sulfur cycle is used to propagate and distribute atmospherically derived S MIF from its delivery to the ocean to its preservation in the sediment. Bulk pyrite in most sediments carries weak S MIF because of microbial reduction of most sulfur compounds to form isotopically homogeneous sulfide. Locally, differential incorporation of sulfur compounds into pyrite leads to preservation of S MIF, which is predicted to be most highly variable in nonmarine and shallow-water settings. The Archean ocean is efficient in diluting primary atmospheric S MIF in the marine pools of sulfate and elemental sulfur with inputs from SO2 and H2S, respectively. Preservation of S MIF with the observed range of magnitudes requires the S MIF production mechanism to be moderately fractionating (20–40‰). Constraints from the marine sulfur cycle allow that either elemental sulfur or organosulfur compounds (or both) carried S MIF to the surface, with opposite sign to S MIF in SO2 and H2SO4. Optimal progress requires observations from nonmarine and shallow-water environments and experimental constraints on the reaction of photoexcited SO2 with atmospheric hydrocarbons. PMID:23572589

Halevy, Itay

2013-01-01

71

Development of enhanced sulfur rejection processes. First Quarterly technical progress report, October 1, 1992--December 31, 1992  

SciTech Connect

Research at Virginia Tech led to two complementary concepts for improving the removal of inorganic sulfur from much of the Eastern US coals. One controls the surface properties of coal pyrite (FeS{sub 2}) by electrochemical-.potential control, referred to as the Electrochemically Enhanced Sulfur Rejection (EESR) Process: The second controls the flotation of middlings, i.e., particles composed of pyrite with coal inclusions by using polymeric reagents to react with pyrite and convert the middlings to hydrophilic particles, and is termed the Polymer Enhanced Sulfur Rejection (PESR) Process. These new concepts are based on recent research establishing the two main reasons why flotation fails to remove more than about 50% of the pyritic sulfur from coal: superficial oxidization of liberated pyrite to form polysulfide oxidation products so that a part of the liberated pyrite floats with the coal; and hydrophobic coal inclusions in the middlings dominating their flotation so that the middlings also float with the coal. These new pyritic-sulfur rejection processes do not require significant modifications of existing coal preparation facilities, enhancing their adoptability by the coal industry. It is believed that they can be used simultaneously to achieve both free pyrite and locked pyrite rejection.

Yoon, R.H.; Luttrell, G.; Adel, G.; Richardson, P.E.

1993-03-23

72

Sulfuric acid-sulfur heat storage cycle  

DOEpatents

A method of storing heat is provided utilizing a chemical cycle which interconverts sulfuric acid and sulfur. The method can be used to levelize the energy obtained from intermittent heat sources, such as solar collectors. Dilute sulfuric acid is concentrated by evaporation of water, and the concentrated sulfuric acid is boiled and decomposed using intense heat from the heat source, forming sulfur dioxide and oxygen. The sulfur dioxide is reacted with water in a disproportionation reaction yielding dilute sulfuric acid, which is recycled, and elemental sulfur. The sulfur has substantial potential chemical energy and represents the storage of a significant portion of the energy obtained from the heat source. The sulfur is burned whenever required to release the stored energy. A particularly advantageous use of the heat storage method is in conjunction with a solar-powered facility which uses the Bunsen reaction in a water-splitting process. The energy storage method is used to levelize the availability of solar energy while some of the sulfur dioxide produced in the heat storage reactions is converted to sulfuric acid in the Bunsen reaction.

Norman, John H. (LaJolla, CA)

1983-12-20

73

Characterization of Phenolic Constituents Inhibiting the Formation of Sulfur-Containing Volatiles Produced during Garlic Processing.  

PubMed

Garlic (Allium sativum L.), which is a widely distributed plant, is globally used as both spice and food. This study identified five novel phenolic compounds, namely, 8-(3-methyl-(E)-1-butenyl)diosmetin, 8-(3-methyl-(E)-1-butenyl)chrysin, 6-(3-methyl-(E)-1-butenyl)chrysin, and Alliumones A and B, along with nine known compounds 6-14 from the ethanol extract of garlic. The structures of these five novel phenolic compounds were established via extensive 1D- and 2D-nuclear magnetic resonance spectroscopy experiments. The effects of the phenolic compounds isolated from garlic on the enzymatical or nonenzymatical formation of sulfur-containing compounds produced during garlic processing were examined. Compound 12 significantly reduced the thermal decomposition of alliin, whereas compound 4 exhibited the highest percentage of alliinase inhibition activity (36.6%). PMID:25579175

Li, Wen-Qing; Zhou, Hua; Zhou, Mei-Yun; Hu, Xing-Peng; Ou, Shi-Yi; Yan, Ri-An; Liao, Xiao-Jian; Huang, Xue-Song; Fu, Liang

2015-01-28

74

Process for producing low-sulfur boiler fuel by hydrotreatment of solvent deashed SRC  

DOEpatents

In this invention, a process is disclosed characterized by heating a slurry of coal in the presence of a process-derived recycle solvent and passing same to a dissolver zone, separating the resultant gases and liquid/solid products therefrom, vacuum distilling the liquid/solids products, separating the portions of the liquid/solids vacuum distillation effluent into a solid ash, unconverted coal particles and SRC material having a boiling point above 850.degree. F. and subjecting same to a critical solvent deashing step to provide an ash-free SRC product. The lighter liquid products from the vacuum distillation possess a boiling point below 850.degree. F. and are passed through a distillation tower, from which recycled solvent is recovered in addition to light distillate boiling below 400.degree. F. (overhead). The ash-free SRC product in accompanyment with at least a portion of the process derived solvent is passed in combination to a hydrotreating zone containing a hydrogenation catalyst and in the presence of hydrogen is hydroprocessed to produce a desulfurized and denitrogenized low-sulfur, low-ash boiler fuel and a process derived recycle solvent which is recycled to slurry the coal in the beginning of the process before heating.

Roberts, George W. (Emmaus, PA); Tao, John C. (Perkiomenville, PA)

1985-01-01

75

Sulfur behavior in the Sasol-Lurgi fixed-bed dry-bottom gasification process  

SciTech Connect

This article reports on the findings of a study regarding the sulfur behavior across a Sasol-Lurgi gasifier. This was undertaken to understand the behavior of the various sulfur-bearing components in the coal, as they are exposed to the conditions in the gasifier. In this study, conventional characterization techniques were employed to monitor the behavior of sulfur-bearing mineral matter across the gasifier. It was observed from the study that the sulfur-bearing mineral (pyrite) in the coal structure undergoes various changes with pyrite being transformed to pyrrhotite and then to various oxides of iron with the subsequent loss of sulfur to form H{sub 2}S. A low proportion of the sulfur species including the organically associated sulfur was encapsulated by a melt that was formed by the interaction between kaolinite and fluxing minerals (pyrite, calcite, and dolomite/ankerite) present in the coal at elevated temperatures and pressure, thereby ending up in the ash. The remaining small proportions of sulfur-bearing mineral matter including pyrite and organically bound sulfur in the unburned carbon in the carbonaceous shales also report to the ash. 18 refs., 8 figs., 2 tabs.

M. Pat Skhonde; R. Henry Matjie; J. Reginald Bunt; A. Christien Strydom; H. Schobert [Sasol Technology R& amp; D, Sasolburg (South Africa)

2009-01-15

76

Sulfur barrier for use with in situ processes for treating formations  

DOEpatents

Methods for forming a barrier around at least a portion of a treatment area in a subsurface formation are described herein. Sulfur may be introduced into one or more wellbores located inside a perimeter of a treatment area in the formation having a permeability of at least 0.1 darcy. At least some of the sulfur is allowed to move towards portions of the formation cooler than the melting point of sulfur to solidify the sulfur in the formation to form the barrier.

Vinegar, Harold J. (Bellaire, TX); Christensen, Del Scot (Friendswood, TX)

2009-12-15

77

Process for preparing a sulfurized molybdenum-containing composition and lubricating oil containing said composition  

SciTech Connect

Antioxidant additives for lubricating oil are prepared by combining a polar promoter, ammonium tetrathiomolybdate, and a basic nitrogen compound complex to form a sulfur- and molybdenumcontaining composition.

Devries, L.; King, J.M.

1981-08-11

78

Conjugated processes of the chemical transformation of sulfur dioxide under the effect of chain gas-phase reactions  

NASA Astrophysics Data System (ADS)

The effect sulfur dioxide has on the dynamics of the spontaneous ignition of hydrogen-oxygen mixtures is studied. Additives of SO2 have no negative effect on spontaneous ignition and undergo chemical conversion to form elemental sulfur. The results are analyzed using the theory of branched chain reactions along with data on SO2 conversion under the action of chain reactions of hydrocarbon oxidation and slow hydrogen oxidation. The transformations classified as parallel reactions from the viewpoint of formal kinetics could actually be conjugated radical-chain processes.

Mantashyan, A. A.

2015-01-01

79

Development of enhanced sulfur rejection processes. Second quarterly technical progress report, January 1, 1993--March 31, 1993  

SciTech Connect

Research at Virginia Tech led to the development of two complementary concepts for improving the removal of inorganic sulfur from many eastern US coals. These concepts are referred to as Electrochemically Enhanced Sulfur Rejection (EESR) and Polymer Enhanced Sulfur Rejection (PESR). The EESR process uses electrochemical techniques to suppress the formation of hydrophobic oxidation products believed to be responsible for the floatability of coal pyrite. The PESR process uses polymeric reagents that react with pyrite and convert floatable middlings, i.e., composite particles composed of pyrite with coal inclusions, into hydrophilic particles. These new pyritic-sulfur rejection processes do not require significant modifications to existing coal preparation facilities, thereby enhancing their adoptability by the coal industry. It is believed that these processes can be used simultaneously to maximize the rejection of both well-liberated pyrite and composite coal-pyrite particles. The technical research was initiated on October 1, 1992, and a detailed work plan and work schedule were developed. During this reporting period, research was conducted to evaluate the liberation characteristics of various pyrite samples, to determine the electrochemical reactions that influence the hydrophobicity of pyrite, and to examine the potential use of electrochemical methods for controlling the flotation and depression of pyrite.

Yoon, R.H.; Luttrell, G.; Adel, G.; Richardson, P.E.

1993-06-14

80

Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes.  

PubMed

Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH(3)), sulfur dioxide (SO(2)), hydrogen sulfide (H(2)S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO(2) and H(2)S emissions in the H(2)SO(4) conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant release of NH(3). PMID:22902143

Liu, Huan; Luo, Guang-Qian; Hu, Hong-Yun; Zhang, Qiang; Yang, Jia-Kuan; Yao, Hong

2012-10-15

81

Effects of different garlic-derived allyl sulfides on peroxidative processes and anaerobic sulfur metabolism in mouse liver.  

PubMed

Biological activity of garlic has been attributed to organosulfur compounds, most of all to oil-soluble allyl sulfides, such as diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS). This study evaluated the effectiveness of garlic-derived allyl sulfides in influencing peroxidative processes, levels of thiols and sulfane sulfur and its metabolic enzymes in normal mouse liver cells. Various allyl sulfides (DAS, DADS and DATS) dissolved in corn oil were given intraperitoneally to mice for 10 days. After sacrificing the mice, biochemical assays were performed in liver homogenates and in plasma in order to establish liver function. All allyl sulfides under study had a beneficial effect in the mouse liver since they decreased reactive oxygen species and malondialdehyde levels and increased glutathione S-transferase activity and non-protein sulfhydryl group level. Moreover, DADS and DATS elevated total sulfane sulfur pool and activity of sulfane sulfur biosynthetic enzymes. The increase in sulfane sulfur level entailed augmentation of its antioxidant and regulatory capacities. Garlic-derived allyl sulfides exhibited antioxidant action in the liver and elevated anaerobic cysteine metabolism leading to the formation of sulfane sulfur-containing compounds. Thus, DADS and DATS showed beneficial action in the liver, which can be used for protection of normal liver cells during chemotherapy or for alleviation of liver damage. PMID:21815229

Iciek, Ma?gorzata B; Kowalczyk-Pachel, Danuta; Kwiecie?, Inga; Dudek, Magdalena B

2012-03-01

82

EFFECT OF FUEL SULFUR ON NITROGEN OXIDE FORMATION IN COMBUSTION PROCESSES  

EPA Science Inventory

The report gives results of research that focuses on the questions: is the sulfur content of a fuel likely to have a major influence on the resulting NOx emissions; and does the presence of fuel sulfur cause major changes in mechanisms of fuel NO formation. Research results will ...

83

SUMMARY REPORT: SULFUR OXIDES CONTROL TECHNOLOGY SERIES: FGD LIME/LIMESTONE PROCESSES  

EPA Science Inventory

This summary report describes the use of lime or limestone as an option for the treatment of sulfur oxides at fossil fuel steam and electric generating facilities. n this treatment, an aqueous slurry of slaked lime or wet ground limestone absorbs sulfur oxide from flue gas. bsorb...

84

Molecular Structure of sulfur  

NSDL National Science Digital Library

The discoverer of sulfur remains anonymous because of lack of records. However, one can trace back to the discovery of R.W. Wood when he used ultra-violet rays to find a sulfur deposit near the crater of Aristarchus on the moon. Sulfur is also found in meteorites. In the United States, Sulfur can be found along the Gulf Coast in wells sunk along salt domes. It is brought to the surface using the Frasch Process in which heated water is forced into the wells and melts the surface. Sulfur may also be found in volcanos or hot springs. Other uses of Sulfur include making phosphatic fertilizers, matches, and medicine. The mineral is a good insulator and takes part in bleaching dried fruit. Sulfur is a minor constitute of body fluids, fats, and skeletal minerals. It can be said that Sulfur is essential to life.

2002-08-26

85

Sulfur and Sulfuric Acid  

NASA Astrophysics Data System (ADS)

Sulfur is one of the few elements that is found in its elemental form in nature. Typical sulfur deposits occur in sedimentary limestone/gypsum formations, in limestone/anhydrite formations associated with salt domes, or in volcanic rock.1 A yellow solid at normal temperatures, sulfur becomes progressively lighter in color at lower temperatures and is almost white at the temperature of liquid air. It melts at 114-119°C (depending on crystalline form) to a transparent light yellow liquid as the temperature is increased. The low viscosity of the liquid begins to rise sharply above 160°C, peaking at 93 Pa·s at 188°C, and then falling as the temperature continues to rise to its boiling point of 445°C. This and other anomalous properties of the liquid state are due to equilibria between the various molecular species of sulfur, which includes small chains and rings.

D'Aquin, Gerard E.; Fell, Robert C.

86

Sulfur in serpentinized oceanic peridotites: Serpentinization processes and microbial sulfate reduction  

USGS Publications Warehouse

The mineralogy, contents, and isotopic compositions of sulfur in oceanic serpentinites reflect variations in temperatures and fluid fluxes. Serpentinization of <1 Ma peridotites at Hess Deep occurred at high temperatures (200??-400??C) and low water/rock ratios. Oxidation of ferrous iron to magnetite maintained low fO2and produced a reduced, low-sulfur assemblage including NiFe alloy. Small amounts of sulfate reduction by thermophilic microbes occurred as the system cooled, producing low-??34S sulfide (1.5??? to -23.7???). In contrast, serpentinization of Iberian Margin peridotites occurred at low temperatures (???20??-200??C) and high water/rock ratios. Complete serpentinization and consumption of ferrous iron allowed evolution to higher fO2. Microbial reduction of seawater sulfate resulted in addition of low-??34S sulfide (-15 to -43???) and formation of higher-sulfur assemblages that include valleriite and pyrite. The high SO4/total S ratio of Hess Deep serpentinites (0.89) results in an increase of total sulfur and high ??34S of total sulfur (mean ??? 8???). In contrast, Iberian Margin serpentinites gained large amounts of 34S-poor sulfide (mean total S = 3800 ppm), and the high sulfide/total S ratio (0.61) results in a net decrease in ??34S of total sulfur (mean ??? -5???). Thus serpentinization is a net sink for seawater sulfur, but the amount fixed and its isotopic composition vary significantly. Serpentinization may result in uptake of 0.4-14 ?? 1012 g S yr-1 from the oceans, comparable to isotopic exchange in mafic rocks of seafloor hydrothermal systems and approaching global fluxes of riverine sulfate input and sedimentary sulfide output.

Alt, J.C.; Shanks, W. C., III

1998-01-01

87

Visible light-induced oxidation of lipid components of purple sulfur bacteria: a significant process in microbial mats  

Microsoft Academic Search

Visible light-induced degradation processes were studied in vitro in senescent cells of two purple sulfur bacteria (Thiohalocapsa halophila and Halochromatium salexigens) isolated from microbial mats from Camargue (France). These reactions act on the phytyl side chain of bacteriochlorophyll-a and on palmitoleic and cis-vaccenic acids. The experiments also confirmed some previous results, i.e. the regiospecific enzymatic oxygenation of the allylic carbon

Daphné Marchand; Jean-François Rontani

2003-01-01

88

ADVANCED SULFUR CONTROL CONCEPTS  

SciTech Connect

Conventional sulfur removal in integrated gasification combined cycle (IGCC) power plants involves numerous steps: COS (carbonyl sulfide) hydrolysis, amine scrubbing/regeneration, Claus process, and tail-gas treatment. Advanced sulfur removal in IGCC systems involves typically the use of zinc oxide-based sorbents. The sulfides sorbent is regenerated using dilute air to produce a dilute SO{sub 2} (sulfur dioxide) tail gas. Under previous contracts the highly effective first generation Direct Sulfur Recovery Process (DSRP) for catalytic reduction of this SO{sub 2} tail gas to elemental sulfur was developed. This process is currently undergoing field-testing. In this project, advanced concepts were evaluated to reduce the number of unit operations in sulfur removal and recovery. Substantial effort was directed towards developing sorbents that could be directly regenerated to elemental sulfur in an Advanced Hot Gas Process (AHGP). Development of this process has been described in detail in Appendices A-F. RTI began the development of the Single-step Sulfur Recovery Process (SSRP) to eliminate the use of sorbents and multiple reactors in sulfur removal and recovery. This process showed promising preliminary results and thus further process development of AHGP was abandoned in favor of SSRP. The SSRP is a direct Claus process that consists of injecting SO{sub 2} directly into the quenched coal gas from a coal gasifier, and reacting the H{sub 2}S-SO{sub 2} mixture over a selective catalyst to both remove and recover sulfur in a single step. The process is conducted at gasifier pressure and 125 to 160 C. The proposed commercial embodiment of the SSRP involves a liquid phase of molten sulfur with dispersed catalyst in a slurry bubble-column reactor (SBCR).

Apostolos A. Nikolopoulos; Santosh K. Gangwal; William J. McMichael; Jeffrey W. Portzer

2003-01-01

89

Removal of organic and inorganic sulfur from Ohio coal by combined physical and chemical process. Final report  

SciTech Connect

This project consisted of three sections. In the first part, the physical cleaning of Ohio coal by selective flocculation of ultrafine slurry was considered. In the second part, the mild oxidation process for removal of pyritic and organic sulfur.was investigated. Finally, in-the third part, the combined effects of these processes were studied. The physical cleaning and desulfurization of Ohio coal was achieved using selective flocculation of ultrafine coal slurry in conjunction with froth flotation as flocs separation method. The finely disseminated pyrite particles in Ohio coals, in particular Pittsburgh No.8 seam, make it necessary to use ultrafine ({minus}500 mesh) grinding to liberate the pyrite particles. Experiments were performed to identify the ``optimum`` operating conditions for selective flocculation process. The results indicated that the use of a totally hydrophobic flocculant (FR-7A) yielded the lowest levels of mineral matters and total sulfur contents. The use of a selective dispersant (PAAX) increased the rejection of pyritic sulfur further. In addition, different methods of floc separation techniques were tested. It was found that froth flotation system was the most efficient method for separation of small coal flocs.

Attia, Y.A.; Zeky, M.El.; Lei, W.W.; Bavarian, F.; Yu, S. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

1989-04-28

90

Surface acoustic wave sensors/gas chromatography; and Low quality natural gas sulfur removal and recovery CNG Claus sulfur recovery process  

SciTech Connect

This topical report consists of the two titled projects. Surface Acoustic Wave/Gas Chromatography (SAW/GC) provides a cost-effective system for collecting real-time field screening data for characterization of vapor streams contaminated with volatile organic compounds (VOCs). The Model 4100 can be used in a field screening mode to produce chromatograms in 10 seconds. This capability will allow a project manager to make immediate decisions and to avoid the long delays and high costs associated with analysis by off-site analytical laboratories. The Model 4100 is currently under evaluation by the California Environmental Protection Agency Technology Certification Program. Initial certification focuses upon the following organics: cis-dichloroethylene, chloroform, carbon tetrachloride, trichlorethylene, tetrachloroethylene, tetrachloroethane, benzene, ethylbenzene, toluene, and o-xylene. In the second study the CNG Claus process is being evaluated for conversion and recovery of elemental sulfur from hydrogen sulfide, especially found in low quality natural gas. This report describes the design, construction and operation of a pilot scale plant built to demonstrate the technical feasibility of the integrated CNG Claus process.

Klint, B.W.; Dale, P.R.; Stephenson, C.

1997-12-01

91

Development of a solid absorption process for removal of sulfur from fuel gas. First quarterly technical report  

SciTech Connect

Battelle Pacific Northwest Laboratories has begun to develop a project for removing sulfur compounds from fuel gases at elevated temperature (> 700/sup 0/C) based on the use of molten mixtures of alkali metal carbonates and calcium carbonate as the active reactants. The sulfur removal capacity of the molten salt mixture may be regenerated by stripping with CO/sub 2/ and steam, usually at a reduced temperature. In this process, the molten salt mixture is contained within the pores of a porous ceramic substrate material which may be used in a packed bed, moving bed, or fluidized bed absorber. The process would be used most advantageously in applications where it is desirable to reduce or eliminate any cooling of the fuel gas between the gasifier outlet and the gas user. Examples of such applications include gas turbines, high temperature fuel cells, boilers, and furnaces which operate in relatively close proximity to a coal gasifier. In these applications, reduction or elimination of the gas cooling requirements will generally improve thermal efficiency by retaining the sensible heat in the gas and may result in simplification of the process by elimination of gas cooling (and in some cases reheating) equipment and by elimination of process condensates and the equipment required for their handling and treatment. The objectives of the program are to obtain process and materials data sufficient to demonstrate feasibility of the process at bench scale and to allow preliminary economic analysis. Process data to be obtained include sorbent sulfur capacity, reaction kinetics, and other operating characteristics. Various candidate materials will be purchased or fabricated and tested for suitability as porous ceramic substrate materials.

Stegen, G.E.; Olson, K.M.

1980-05-01

92

Process for preparing a sulfurized molybdenum-containing composition and lubricating oil containing the composition  

SciTech Connect

Antioxidant additives for lubricating oil are prepared by (1) combining a polar solvent, an acidic molybdenum compound and an oil-soluble basic nitrogen compound to form molybdenum-containing complex and (2) contacting said complex with carbon disulfide to form a sulfur-and molybdenum-containing composition.

Devries, L.; King, J.M.

1981-08-25

93

The Sulfur-Iodine Cycle: Process Analysis and Design Using Comprehensive Phase Equilibrium Measurements and Modeling  

SciTech Connect

Of the 100+ thermochemical hydrogen cycles that have been proposed, the Sulfur-Iodine (S-I) Cycle is a primary target of international interest for the centralized production of hydrogen from nuclear power. However, the cycle involves complex and highly nonideal phase behavior at extreme conditions that is only beginning to be understood and modeled for process simulation. The consequence is that current designs and efficiency projections have large uncertainties, as they are based on incomplete data that must be extrapolated from property models. This situation prevents reliable assessment of the potential viability of the system and, even more, a basis for efficient process design. The goal of this NERI award (05-006) was to generate phase-equilibrium data, property models, and comprehensive process simulations so that an accurate evaluation of the S-I Cycle could be made. Our focus was on Section III of the Cycle, where the hydrogen is produced by decomposition of hydroiodic acid (HI) in the presence of water and iodine (I2) in a reactive distillation (RD) column. The results of this project were to be transferred to the nuclear hydrogen community in the form of reliable flowsheet models for the S-I process. Many of the project objectives were achieved. At Clemson University, a unique, tantalum-based, phase-equilibrium apparatus incorporating a view cell was designed and constructed for measuring fluid-phase equilibria for mixtures of iodine, HI, and water (known as HIx) at temperatures to 350 °C and pressures to 100 bar. Such measurements were of particular interest for developing a working understanding of the expected operation of the RD column in Section III. The view cell allowed for the IR observation and discernment of vapor-liquid (VL), liquid-liquid, and liquid-liquid-vapor (LLVE) equilibria for HIx systems. For the I2-H2O system, liquid-liquid equilibrium (LLE) was discovered to exist at temperatures up to 310-315 °C, in contrast to the models and predictions of earlier workers. For the I2-HI-H2O ternary, LLE and LLVE were all observed for the first time at temperatures of 160 and 200 °C. Three LLE tie-lines were measured at 160 °C, and preliminary indications are that the underlying phase behavior could result in further improvements in the performance of the S-I Cycle. Unfortunately, these new results were obtained too late in the project to be incorporated into the modeling and simulation work described below. At the University of Virginia, a uniquely complete and reliable model was developed for the thermodynamic properties of HIx, covering the range of conditions expected for the separation of product hydrogen and recycled iodine in the RD column located in Section III. The model was validated with all available property spectroscopy data. The results provide major advances over prior understanding of the chemical speciation involved. The model was implemented in process simulation studies of the S-I Cycle, which showed improvement in energy efficiency to 42%, as well as significantly smaller capital requirements due to lower pressure operation and much smaller equipment sizes. The result is that the S-I Cycle may be much more economically feasible than was previously thought. If both the experimental and modeling work described above were to be continued to ultimate process optimization, both the American public and the global community would benefit from this alternative energy source that does not produce carbon emissions.

Thies, Mark C.; O'Connell, J. P.; Gorensek, Maximilian B.

2010-01-10

94

Heterotrophic and elemental-sulfur-based autotrophic denitrification processes for simultaneous nitrate and Cr(VI) reduction.  

PubMed

Nitrate and chromate can be present together in water resources as nitrate is a common co-contaminant in surface and ground waters. This study aims at comparatively evaluating simultaneous chromate and nitrate reduction in heterotrophic and sulfur-based autotrophic denitrifying column bioreactors. In sulfur-based autotrophic denitrification process, elemental sulfur and nitrate act as an electron donor and an acceptor, respectively, without requirement of organic supplementation. Autotrophic denitrification was complete and not adversely affected by chromate up to 0.5 mg/L. Effluent chromate concentration was <50 ?g/L provided that influent chromate concentration was ?0.5 mg/L. Heterotrophic denitrification performance was not adversely affected even at 20 mg/L chromate and complete chromate reduction was attained up to 10 mg/L. Although autotrophic denitrification rate was much lower compared with heterotrophic one, it may be preferred in drinking water treatment due to the elimination of organic supplementation and the risk of treated effluent contamination. PMID:24384544

Sahinkaya, Erkan; Kilic, Adem

2014-03-01

95

Controlled Nucleation and Growth Process of Li2S2/Li2S in Lithium-Sulfur Batteries  

SciTech Connect

Lithium-sulfur battery is a promising next-generation energy storage system because of its potentially three to five times higher energy density than that of traditional lithium ion batteries. However, the dissolution and precipitation of soluble polysulfides during cycling initiate a series of key-chain reactions that significantly shorten battery life. Herein, we demonstrate that through a simple but effective strategy, significantly improved cycling performance is achieved for high sulfur loading electrodes through controlling the nucleation and precipitation of polysulfieds on the electrode surface. More than 400 or 760 stable cycling are successfully displayed in the cells with locked discharge capacity of 625 mAh g-1 or 500 mAh g-1, respectively. The nucleation and growth process of dissolved polysulfides has been electrochemically altered to confine the thickness of discharge products passivated on the cathode surface, increasing the utilization rate of sulfur while avoiding severe morphology changes on the electrode. More importantly, the exposure of new lithium metal surface to the S-containing electrolyte is also greatly reduced through this strategy, largely minimizing the anode corrosion caused by polysulfides. This work interlocks the electrode morphologies and its evolution with electrochemical interference to modulate cell performances by using Li-S system as a platform, providing different but critical directions for this community.

Zheng, Jianming; Gu, Meng; Wang, Chong M.; Zuo, Pengjian; Koech, Phillip K.; Zhang, Jiguang; Liu, Jun; Xiao, Jie

2013-09-20

96

Fluid catalytic cracking catalyst for cracking sulfur containing petroleum feedstocks and a process for using it  

Microsoft Academic Search

A fluid catalytic cracking catalyst is described comprising a blend of a catalytically active first component and a second component for reducing the emissions of oxides of sulfur from the regenerator of a fluid catalytic cracking unit, the catalyst comprising: (a) about 10-70% by weight of fluidizable particles comprising at least about 40% by weight Y-faujasite; and (b) about 30-90%

J. W. Byrne; B. K. Speronello

1986-01-01

97

Transition metal-catalyzed oxidation of sulfur(IV) oxides. Atmospheric-relevant processes and mechanisms  

Microsoft Academic Search

The transition metal-catalyzed oxidation of sulfur(IV) oxides has been known for more than 100 years. There is a significant lack of information on the actual role of the transition metal-catalyzed reactions, and much of the earlier work was performed without a detailed knowledge of the chemical system. For this reason attention is focused on the role of transition metal ions

Christian. Brandt; Rudi. van Eldik

1995-01-01

98

Reactions for improving efficiencies in thermochemical cycles related to the sulfur dioxide-iodine process  

NASA Astrophysics Data System (ADS)

A modification of the sulfur dioxide iodine cycle which uses magnesium oxide, magnesium sulfite and magnesium iodide is examined with particular emphasis on decreasing the amount of water employed and thereby increasing the efficiency. The key reaction is that of iodine with magnesium oxide and magnesium sulfite hexahydrate with no additional water. This produces 77% of the total possible sulfate as well as magnesium iodide, hydrogen iodide and hydrogen at 523 K. The efficiency of this cycle varies between 58% and 39% depending on the amount of heat that can be recovered. This is the first example of a cycle where there is no large energy burden due to evaporation.

Mason, C. F. V.; Bowman, M. G.

1982-06-01

99

Sulfur-oxidizing bacteria dominate the microbial diversity shift during the pyrite and low-grade pyrolusite bioleaching process.  

PubMed

The microbial ecology of the pyrite-pyrolusite bioleaching system and its interaction with ore has not been well-described. A 16S rRNA gene clone library was created to evaluate changes in the microbial community at different stages of the pyrite-pyrolusite bioleaching process in a shaken flask. The results revealed that the bacterial community was disturbed after 5 days of the reaction. Phylogenetic analysis of 16S rRNA sequences demonstrated that the predominant microorganisms were members of a genus of sulfur-oxidizing bacteria, Thiomonas sp., that subsequently remained dominant during the bioleaching process. Compared with iron-oxidizing bacteria, sulfur-oxidizing bacteria were more favorable to the pyrite-pyrolusite bioleaching system. Decreased pH due to microbial acid production was an important condition for bioleaching efficiency. Iron-oxidizing bacteria competed for pyrite reduction power with Mn(IV) in pyrolusite under specific conditions. These results extend our knowledge of microbial dynamics during pyrite-pyrolusite bioleaching, which is a key issue to improve commercial applications. PMID:23673133

Han, Yifan; Ma, Xiaomei; Zhao, Wei; Chang, Yunkang; Zhang, Xiaoxia; Wang, Xingbiao; Wang, Jingjing; Huang, Zhiyong

2013-10-01

100

Specifics of the sulfuric-acid processing of galena concentrates in the presence of nitrous acid  

Microsoft Academic Search

Conclusions  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Nitrous acid has a catalytic effect on the sulfuric-acid decomposition of galena. With oxygen at atmospheric pressure, the\\u000a presence of even small quantities of HNO2 in the solution (0.01 M) at room temperature increases the degree of oxidation of lead sulfide twofold.\\u000a \\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a The solid products of the oxidation of PbS (PbSO4 and S) form a dense film

T. I. Markovich; A. B. Ptitsyn

1998-01-01

101

EFFECT OF ELECTROLYZER CONFIGURATION AND PERFORMANCE ON HYBRID SULFUR PROCESS NET THERMAL EFFICIENCY  

SciTech Connect

Hybrid Sulfur cycle is gaining popularity as a possible means for massive production of hydrogen from nuclear energy. Several different ways of carrying out the SO{sub 2}-depolarized electrolysis step are being pursued by a number of researchers. These alternatives are evaluated with complete flowsheet simulations and on a common design basis using Aspen Plus{trademark}. Sensitivity analyses are performed to assess the performance potential of each configuration, and the flowsheets are optimized for energy recovery. Net thermal efficiencies are calculated for the best set of operating conditions for each flowsheet and the results compared. This will help focus attention on the most promising electrolysis alternatives. The sensitivity analyses should also help identify those features that offer the greatest potential for improvement.

Gorensek, M

2007-03-16

102

Formulation and optimization of biological removal of flue gas pretreatment wastewater and sulfur recycling process by Box-Behnken design.  

PubMed

The aim of this study was to investigate optimum conditions for biological removal of flue gas pretreatment wastewater and achieve maximum elemental sulfur yield. A three-factor, three-level Box-Behnken design was used to derive a second-order polynomial equation and construct contour plots to predict responses. The independent variables selected were hydraulic retention time (X?), inlet sulfate concentration (X?), and air flow (X?). Fifteen batches were done in a biological united system and evaluated for elemental sulfur yield (Y?). The transformed values of the independent variables and Y? were subjected to a full-model second-order polynomial equation. The equation was modified based on Fisher's F- and probability P-values. The computer optimization process and contour plots predicted the values of independent variables X?, X? and X? (16 h, 1,348 mg L?¹ and 165 L h?¹ respectively), for maximized response of Y?. The experimental results at predicted conditions demonstrate that the modified model equation has good applicability to the practical system. PMID:23787307

Wang, Juan; Cao, Yuan; Zhong, Qin

2013-01-01

103

Structural insight into SoxC and SoxD interaction and their role in electron transport process in the novel global sulfur cycle in Paracoccus pantotrophus  

SciTech Connect

Microbial oxidation of reduced inorganic sulfur compounds mainly sulfur anions in the environment is one of the major reactions of the global sulfur cycle mediated by phylogenetically diverse prokaryotes. The sulfur oxidizing gene cluster (sox) of {alpha}-Proteobacteria comprises of at least 16 genes, which form two transcriptional units, viz., soxSRT and soxVWXYZABCDEFGH. Sequence analysis reveals that soxD gene product (SoxD) belongs to the di-heme cytochrome c family of electron transport proteins whereas soxC gene product (SoxC) is a sulfur dehydrogenase. We employed homology modeling to construct the three-dimensional structures of the SoxC and SoxD from Paracoccus pantotrophus. SoxD protein is known to interact with SoxC. With the help of docking studies we have identified the residues involved in the interaction of SoxC and SoxD. The putative active site geometries of these two proteins as well as the structural basis of the involvements of these proteins in electron transport process during the oxidation of sulfur anions are also investigated.

Bagchi, Angshuman [Bioinformatics Center, Bose Institute, AJC Bose Centenary Building, P1/12 CIT Scheme VIIM, Kolkata 700 054 (India)]. E-mail: angshu@bic.boseinst.ernet.in; Roy, Pradosh [Department of Microbiology, Bose Institute, AJC Bose Centenary Building, P1/12 CIT Scheme VIIM, Kolkata 700 054 (India)]. E-mail: prodosh@bic.boseinst.ernet.in

2005-06-17

104

Ferrous iron oxidation by sulfur-oxidizing Acidithiobacillus ferrooxidans and analysis of the process at the levels of transcription and protein synthesis.  

PubMed

In contrast to iron-oxidizing Acidithiobacillus ferrooxidans, A. ferrooxidans from a stationary phase elemental sulfur-oxidizing culture exhibited a lag phase in pyrite oxidation, which is similar to its behaviour during ferrous iron oxidation. The ability of elemental sulfur-oxidizing A. ferrooxidans to immediately oxidize ferrous iron or pyrite without a lag phase was only observed in bacteria obtained from growing cultures with elemental sulfur. However, these cultures that shifted to ferrous iron oxidation showed a low rate of ferrous iron oxidation while no growth was observed. Two-dimensional gel electrophoresis was used for a quantitative proteomic analysis of the adaptation process when bacteria were switched from elemental sulfur to ferrous iron. A comparison of total cell lysates revealed 39 proteins whose increase or decrease in abundance was related to this phenotypic switching. However, only a few proteins were closely related to iron and sulfur metabolism. Reverse-transcription quantitative PCR was used to further characterize the bacterial adaptation process. The expression profiles of selected genes primarily involved in the ferrous iron oxidation indicated that phenotypic switching is a complex process that includes the activation of genes encoding a membrane protein, maturation proteins, electron transport proteins and their regulators. PMID:23291738

Kucera, Jiri; Bouchal, Pavel; Lochman, Jan; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

2013-04-01

105

Sulfuric Acid in the Venus Clouds  

NASA Technical Reports Server (NTRS)

The visible and ultraviolet transmission features of a thin layer of elemental bromine and hydrobromic acid dissolved in sulfuric acid somewhat resemble the Venus spectrum, up to 14 microns. The chemical process postulated for forming sulfuric acid involves the oxidation of sulfur and its compounds to sulfuric acid through the agency of elemental bromine, produced by the photolytic decomposition of hydrogen bromide.

Sill, G. T.

1972-01-01

106

Thiobis(hexamethyldisilazane) as a new precursor for the deposition of sulfur on gold: A one-step concerted adsorption process  

NASA Astrophysics Data System (ADS)

Direct experimental evidence for the deposition of sulfur on gold surfaces using thiobis(hexamethyldisilazane) as a new precursor is provided. The modified surfaces are characterized using cyclic voltammetry, X-ray photoelectron spectroscopy, and scanning tunneling microscopy. XPS and electrochemical results show that the modification process is very fast and that high coverage values are reached within a few minutes. The XPS does not show the initial deposition of fragments of thiobis(hexamethyldisilazane) but only shows the deposition of sulfur even after very short modification times. STM results confirm the formation of dense sulfur films and show the formation of the well-known rectangular structures. Images also show the formation of sulfur multilayers. The electrochemical characteristics of the precursor along with its theoretical investigation and the known chemical reactivity of sulfur transfer agents in organic synthesis rule out the dissociative reductive adsorption process. A concerted adsorption mechanism is proposed and is associated with the concerted cleavage of both SN chemical bonds.

Koczkur, Kallum M.; Houmam, Abdelaziz

2014-06-01

107

Investigation on thiosulfate-involved organics and nitrogen removal by a sulfur cycle-based biological wastewater treatment process.  

PubMed

Thiosulfate, as an intermediate of biological sulfate/sulfite reduction, can significantly improve nitrogen removal potential in a biological sulfur cycle-based process, namely the Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI(®)) process. However, the related thiosulfate bio-activities coupled with organics and nitrogen removal in wastewater treatment lacked detailed examinations and reports. In this study, S2O3(2-) transformation during biological SO4(2-)/SO3(2-) co-reduction coupled with organics removal as well as S2O3(2-) oxidation coupled with chemolithotrophic denitrification were extensively evaluated under different experimental conditions. Thiosulfate is produced from the co-reduction of sulfate and sulfite through biological pathway at an optimum pH of 7.5 for organics removal. And the produced S2O3(2-) may disproportionate to sulfide and sulfate during both biological S2O3(2-) reduction and oxidation most possibly carried out by Desulfovibrio-like species. Dosing the same amount of nitrate, pH was found to be the more direct factor influencing the denitritation activity than free nitrous acid (FNA) and the optimal pH for denitratation (7.0) and denitritation (8.0) activities were different. Spiking organics significantly improved both denitratation and denitritation activities while minimizing sulfide inhibition of NO3(-) reduction during thiosulfate-based denitrification. These findings in this study can improve the understanding of mechanisms of thiosulfate on organics and nitrogen removal in biological sulfur cycle-based wastewater treatment. PMID:25497428

Qian, Jin; Lu, Hui; Cui, Yanxiang; Wei, Li; Liu, Rulong; Chen, Guang-Hao

2015-02-01

108

Sulfur compounds in coal  

NASA Technical Reports Server (NTRS)

The literature on the chemical structure of the organic sulfur compounds (or functional groups) in coal is reviewed. Four methods were applied in the literature to study the sulfur compounds in coal: direct spectrometric and chemical analysis, depolymerization in drastic conditions, depolymerization in mild conditions, and studies on simulated coal. The data suggest that most of the organic sulfur in coal is in the form of thiophenic structures and aromatic and aliphatic sulfides. The relative abundance of the sulfur groups in bituminous coal is estimated as 50:30:20%, respectively. The ratio changes during processing and during the chemical analysis. The main effects are the transformation during processing of sulfides to the more stable thiophenic compounds and the elimination of hydrogen sulfide.

Attar, A.; Corcoran, W. H.

1977-01-01

109

Processing of LEU targets for {sup 99}Mo production -- Dissolution of metal foils by nitric-acid/sulfuric-acid mixtures  

SciTech Connect

The first step in processing low-enriched uranium (LEU) targets for production of {sup 99}Mo is to dissolve the neutron-irradiated uranium foil coming from the reactor. Appropriate conditions for dissolving the foils were determined by measuring the dissolution rates for uranium foil over a wide range of temperatures and acid concentrations. On the basis of these dissolution rates, the process chemistry, and a model that integrates dissolution rates as a function of temperature and composition, a closed stainless-steel dissolver was designed, built, and tested for dissolving up to 18 g of uranium foil. The results were quite successful, with the uranium foil being dissolved within one hour as desired. To do this, the dissolver temperature must be in the range from 97 to 102 C, and the dissolver solution (cocktail) must have a composition of 3M nitric acid and 2M sulfuric acid. The final dissolver solution is subsequently processed to separate {sup 99}Mo from uranium, fission products, and other elements.

Srinivasan, B.; Leonard, R.A.; Aase, S. [and others

1995-09-01

110

IN-PROCESS CONTROL OF NITROGEN AND SULFUR IN ENTRAINED-BED GASIFERS  

EPA Science Inventory

The report gives results of an evaluation of theoretical aspects and engineering considerations of in-process pollutant control of the entrained-bed slagging coal gasification process, as applied to combined cycle operation or to the retrofit of existing boilers. The pollutants o...

111

Lunar sulfur  

NASA Technical Reports Server (NTRS)

Ideas introduced by Vaniman, Pettit and Heiken in their 1988 Uses of Lunar Sulfur are expanded. Particular attention is given to uses of SO2 as a mineral-dressing fluid. Also introduced is the concept of using sulfide-based concrete as an alternative to the sulfur-based concretes proposed by Leonard and Johnson. Sulfur is abundant in high-Ti mare basalts, which range from 0.16 to 0.27 pct. by weight. Terrestrial basalts with 0.15 pct. S are rare. For oxygen recovery, sulfur must be driven off with other volatiles from ilmenite concentrates, before reduction. Troilite (FeS) may be oxidized to magnetite (Fe3O4) and SO2 gas, by burning concentrates in oxygen within a magnetic field, to further oxidize ilmenite before regrinding the magnetic reconcentration. SO2 is liquid at -20 C, the mean temperature underground on the Moon, at a minimum of 0.6 atm pressure. By using liquid SO2 as a mineral dressing fluid, all the techniques of terrestrial mineral separation become available for lunar ores and concentrates. Combination of sulfur and iron in an exothermic reaction, to form iron sulfides, may be used to cement grains of other minerals into an anhydrous iron-sulfide concrete. A sulfur-iron-aggregate mixture may be heated to the ignition temperature of iron with sulfur to make a concrete shape. The best iron, sulfur, and aggregate ratios need to be experimentally established. The iron and sulfur will be by-products of oxygen production from lunar minerals.

Kuck, David L.

1991-01-01

112

Sulfuric acid versus elemental sulfur as by-products. Final report  

Microsoft Academic Search

An economic comparison of sulfuric acid production and sulfur recovery processes was made on eastern coal feeds in this study. Sulfuric acid is the more attractive product whenever assured markets are available, on the basis of rail transportation of by-products. The capital cost is higher for a plant to recover the sulfur, and the product value is lower per unit

1978-01-01

113

Sulfur production continues to rise  

SciTech Connect

Sulfur is one of the world's most-popular commodities. It has another distinctive feature: most of it is produced from the effluent of chemical process plants. A lot more sulfur will have similar origins in the future as countries tighten up on sulfur emissions in a global effort to reduce acid rain. To meet such stricter controls, new sulfur recovery methods are being developed, and existing ones improved, to extract sulfur more efficiently and cheaply. Among the new developments are improvements in the Claus process--and alternatives to Claus--for the extraction of hydrogen sulfide (H[sub 2]S) from process streams; and new ways to recover elemental sulfur from sulfur dioxide (SO[sub 2]) contained in the flue gas of coal-fired plants. Currently, the common flue gas treatment is scrubbing with limestone or lime, but this produces millions of tons/yr of gypsum sludge that is mostly landfilled. Gypsum can be processed into wallboard, but that market is limited. The paper discusses the use of flue gas as a raw material; a versatile acid production process; alternative processes for H[sub 2]S extraction; and a process that recovers both sulfur and hydrogen.

Parkinson, G.; Ondrey, G.; Moore, S.

1994-06-01

114

Effective sulfur and energy recovery from hydrogen sulfide through incorporating an air-cathode fuel cell into chelated-iron process.  

PubMed

The chelated-iron process is among the most promising techniques for the hydrogen sulfide (H2S) removal due to its double advantage of waste minimization and resource recovery. However, this technology has encountered the problem of chelate degradation which made it difficult to ensure reliable and economical operation. This work aims to develop a novel fuel-cell-assisted chelated-iron process which employs an air-cathode fuel cell for the catalyst regeneration. By using such a process, sulfur and electricity were effectively recovered from H2S and the problem of chelate degradation was well controlled. Experiment on a synthetic sulfide solution showed the fuel-cell-assisted chelated-iron process could maintain high sulfur recovery efficiencies generally above 90.0%. The EDTA was preferable to NTA as the chelating agent for electricity generation, given the Coulombic efficiencies (CEs) of 17.8 ± 0.5% to 75.1 ± 0.5% for the EDTA-chelated process versus 9.6 ± 0.8% to 51.1 ± 2.7% for the NTA-chelated process in the pH range of 4.0-10.0. The Fe (III)/S(2-) ratio exhibited notable influence on the electricity generation, with the CEs improved by more than 25% as the Fe (III)/S(2-) molar ratio increased from 2.5:1 to 3.5:1. Application of this novel process in treating a H2S-containing biogas stream achieved 99% of H2S removal efficiency, 78% of sulfur recovery efficiency, and 78.6% of energy recovery efficiency, suggesting the fuel-cell-assisted chelated-iron process was effective to remove the H2S from gas streams with favorable sulfur and energy recovery efficiencies. PMID:24220197

Sun, Min; Song, Wei; Zhai, Lin-Feng; Cui, Yu-Zhi

2013-12-15

115

Effects of ozone and sulfur dioxide on processing tomato yields and quality. Final report  

SciTech Connect

The object of the experiment was to study the effects of SO/sub 2/ and/or ozone on tomato vegetative growth, fruit yields, and fruit quality. Two varieties of processing tomatoes, UC-204-B and E-6203, were exposed to four levels of ozone and two levels of SO/sub 2/. Exposure to ambient ozone caused a 20% reduction in vine weights and 27% reduction in weight of red fruit compared to filtered air. Exposure to 0.1 ppm SO/sub 2/ produced 7% fewer vines and approximately 8% less fruit as compared with no SO/sub 2/ exposure. Fruit quality tests indicated that increasing ozone levels reduce soluble solids (Brix), and they reduce viscosity, an important indicator of processing behavior. Exposure to SO/sub 2/ in the concentrations used increased total solids but had no measurable effect on viscosity or consistency.

Brewer, R.F.

1986-03-01

116

Experimental Behavior of Sulfur Under Primitive Planetary Differentiation Processes, the Sulfide Formations in Enstatite Meteorites and Implications for Mercury  

NASA Astrophysics Data System (ADS)

We have simulated different models of CaS-FeS-MgS sulfide formation and determine the solubility of sulfur in silicate melts at high pressure and high temperatures. We will present their implications for planetary differentiation and Mercury.

Malavergne, V.; Brunet, F.; Righter, K.; Zanda, B.; Avril, C.; Borensztajn, S.; Berthet, S.

2012-03-01

117

Method and system for the removal of oxides of nitrogen and sulfur from combustion processes  

DOEpatents

A process for removing oxide contaminants from combustion gas, and employing a solid electrolyte reactor, includes: (a) flowing the combustion gas into a zone containing a solid electrolyte and applying a voltage and at elevated temperature to thereby separate oxygen via the solid electrolyte, (b) removing oxygen from that zone in a first stream and removing hot effluent gas from that zone in a second stream, the effluent gas containing contaminant, (c) and pre-heating the combustion gas flowing to that zone by passing it in heat exchange relation with the hot effluent gas.

Walsh, John V. (Glendora, CA)

1987-12-15

118

An application of CAMx process analysis tools: Exploring process contributions to extreme ozone, nitrogen oxides and sulfur dioxide  

NASA Astrophysics Data System (ADS)

The University at Albany Air Quality Forecasting Modeling System (AQFMS) is a state-of-the-art model that generates reliable daily and "day-ahead" air quality forecasts for the Northeastern United States. The three major categories of processes which dictate regional air quality are production from emission sources, horizontal and vertical transport driven by the prevailing meteorology, and chemical transformations. The Advanced Research WRF (ARW) produces meteorological fields. The Sparse Matrix Operator for Kernel Emissions (SMOKE) processes available emission inventories for air quality modeling. The Comprehensive Air Quality Model with extension (CAMx) handles both chemical processes and the integration of ARW-WRF and SMOKE in devising separate quantitative contributions to pollutant concentrations from process categories. An AQFMS forecast, though indicative of the temporal and spatial changes in the ambient condition, does not tell us exactly how and why those changes occurred. High concentrations of criteria pollutants during "extreme" conditions could come about in many ways. Process analysis takes a step back in numerical procedures to showcase the partial contribution of 18 different processes to the predicted concentration. Area and point source make up the two emission source processes. Advection and diffusion through the west, east, south, north, bottom and top boundary make up the twelve horizontal and vertical transport processes. Gas phase and heterogeneous chemistry make up the two chemical transformation processes, with dry and wet deposition making up the two physio-chemical removal processes. A group of model defined "extreme" intra-day periods in a 12km by 12km grid spacing over The New York Botanical Gardens were evaluated for model performance at the surface and characterized by distinctive modes in which the aforementioned processes contribute to SO2, NOx and O3 concentrations in the vertical layers up to the first 4km of the model atmosphere. Trustworthy process features were highlighted for species and intra-day periods of satisfactory model performance. These features supplement AQFMS model forecasts of pollutant species concentrations for operational or regulatory pursuits with an enhanced understanding of model process interactions.

Murray, David-anthony

119

Proteomic and transcriptomic analysis of Arabidopsis seeds: molecular evidence for successive processing of seed proteins and its implication in the stress response to sulfur nutrition.  

PubMed

Seed storage proteins are synthesized as sources of carbon, nitrogen and sulfur for the next generation of plants. Their composition changes according to nutritional conditions. Here, we report the precise molecular identification of seed proteins by proteomic analysis of wild-type Arabidopsis thaliana and methionine-over-accumulating mutant mto1-1 plants. The identities of 50 protein spots were determined in the protein extract of mature Arabidopsis seeds by two-dimensional (2D) gel electrophoresis and subsequent mass spectrometric analysis. Of these protein spots, 42 were identified as derived from 12S globulins or 2S albumins. These results indicate that approximately 84% of protein species in Arabidopsis seeds are derived from a few genes coding for 12S globulins and 2S albumins. Extensive mass spectrometric analysis of the 42 spots revealed that successive C-terminal degradation occurred on the 12S globulins. The feasibility of this C-terminal processing was rationalized by molecular modeling of the three-dimensional structure of 12S globulins. The C-terminal degradation at glutamic acid residues of the 12S globulin subunits was repressed under sulfur-deficient conditions. Transcriptome analysis was combined with proteomic analysis to elucidate the mechanism of changes in seed protein composition in response to sulfur deficiency. The results suggest that seed storage proteins in Arabidopsis undergo multi-layer regulation, with emphasis on post-translational modifications that enable the plant to respond to sulfur deficiency. PMID:17059406

Higashi, Yasuhiro; Hirai, Masami Yokota; Fujiwara, Toru; Naito, Satoshi; Noji, Masaaki; Saito, Kazuki

2006-11-01

120

Understanding Sulfur Systematics in Large Igneous Provinces Using Sulfur Isotopes  

NASA Astrophysics Data System (ADS)

The eruption of the Siberian Traps coincided with perhaps the greatest environmental catastrophe in Earth's history, at the Permo-Triassic boundary. The source and magnitude of the volatile emissions, including sulfur, associated with the eruption remain poorly understood yet were critical in forcing environmental change. Two of the primary questions are how much sulfur gases were emitted during the eruptions and from where they were sourced. Primary melts carry dissolved sulfur from the mantle. Magmas ponding in sills and ascending through dykes may also assimilate sulfur from country rocks, as well as heat the country rocks and generate fluids through contact metamorphism. If the magmas interacted thermally, for prolonged periods, with sulfur-rich country rocks then it is probable that the sulfur budget of these eruptions might have been augmented considerably. This is exactly what we have shown recently for a basaltic sill emplaced in oil shale that fed eruptions of the British Tertiary Province, where surrounding sediments showed extensive desulfurization (Yallup et al. Geoch. Cosmochim. Acta, online, 2013). In the current study sulfur isotopes and trace element abundances are used to discriminate sulfur sources and to model magmatic processes for a suite of Siberian Traps sill and lava samples. Our bulk rock and pyrite geochemical analyses illustrate clearly their high abundance of 34S over 32S. The high 34S/32S has been noted previously and linked to assimilation of sulfur from sediments but may alternatively be inherited from the mantle plume source. With the aim of investigating the sulfur isotopic signature in the melt prior to devolatilization, we use secondary ion mass spectrometry (SIMS), for which a specific set of glass standards was synthesised. In order to understand how sulfur isotopes fractionate during degassing we have also conducted a parallel study of well-characterized tephras from Kilauea Volcano, where sulfur degassing behavior is well known.

Novikova, S.; Edmonds, M.; Turchyn, A. V.; Maclennan, J.; Svensen, H.; Frost, D. J.; Yallup, C.

2013-12-01

121

Study on the destructive effect to inherent quality of Fritillaria thunbergii Miq. (Zhebeimu) by sulfur-fumigated process using chromatographic fingerprinting analysis.  

PubMed

The after-harvesting sun-dried processing of Fritillariae thunbergii bulbus (Zhebeimu) was the traditional treatment for commodity. Over recent decades the natural drying process for bulbus of Fritillariae has been replaced by sulfur-fumigation for reducing the drying duration and pest control. We used ultra-performance liquid chromatography coupled with evaporative light scattering detection (UPLC-ELSD) fingerprinting analysis and major alkaloids determination to investigate the potential damaging effect of the sulfur-fumigating process. The experimental conditions were as follows: Chromatography was proceeded on Waters Acquity UPLC BEH C(18) column; the linear gradient elution was conducted with mobile phase prepared from acetonitrile-0.02% triethylamine; the drift tube temperature was set at 40°C with a nitrogen flow-rate of 30psi, and the spray parameter was set 40%. All calibration curves showed good linear regression (R>0.9991) within the tested range. The method was validated for precision, accuracy, limit of detection and quantification. The study also has shown that sulfur-fumigated samples had significant loss of the main active compounds and a more destructive fingerprint profile when compared to the sun-dried samples. PMID:22326548

Duan, Baozhong; Huang, Linfang; Chen, Shilin

2012-04-15

122

Synthesis and development of processes for the recovery of sulfur from acid gases. Part 1, Development of a high-temperature process for removal of H{sub 2}S from coal gas using limestone -- thermodynamic and kinetic considerations; Part 2, Development of a zero-emissions process for recovery of sulfur from acid gas streams  

SciTech Connect

Limestone can be used more effectively as a sorbent for H{sub 2}S in high-temperature gas-cleaning applications if it is prevented from undergoing calcination. Sorption of H{sub 2}S by limestone is impeded by sintering of the product CaS layer. Sintering of CaS is catalyzed by CO{sub 2}, but is not affected by N{sub 2} or H{sub 2}. The kinetics of CaS sintering was determined for the temperature range 750--900{degrees}C. When hydrogen sulfide is heated above 600{degrees}C in the presence of carbon dioxide elemental sulfur is formed. The rate-limiting step of elemental sulfur formation is thermal decomposition of H{sub 2}S. Part of the hydrogen thereby produced reacts with CO{sub 2}, forming CO via the water-gas-shift reaction. The equilibrium of H{sub 2}S decomposition is therefore shifted to favor the formation of elemental sulfur. The main byproduct is COS, formed by a reaction between CO{sub 2} and H{sub 2}S that is analogous to the water-gas-shift reaction. Smaller amounts of SO{sub 2} and CS{sub 2} also form. Molybdenum disulfide is a strong catalyst for H{sub 2}S decomposition in the presence of CO{sub 2}. A process for recovery of sulfur from H{sub 2}S using this chemistry is as follows: Hydrogen sulfide is heated in a high-temperature reactor in the presence of CO{sub 2} and a suitable catalyst. The primary products of the overall reaction are S{sub 2}, CO, H{sub 2} and H{sub 2}O. Rapid quenching of the reaction mixture to roughly 600{degrees}C prevents loss Of S{sub 2} during cooling. Carbonyl sulfide is removed from the product gas by hydrolysis back to CO{sub 2} and H{sub 2}S. Unreacted CO{sub 2} and H{sub 2}S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H{sub 2} and CO, which recovers the hydrogen value from the H{sub 2}S. This process is economically favorable compared to the existing sulfur-recovery technology and allows emissions of sulfur-containing gases to be controlled to very low levels.

Towler, G.P.; Lynn, S.

1993-05-01

123

Development of instrumental methods of analysis of sulfur compounds in coal process streams. Ninth quarterly technical progress report, October-December 1979  

SciTech Connect

Capabilities for constructing multidimensional Pourbaix Diagrams have been expanded. New algorithms have been developed for the generation of abundance profiles and for delineating thermodynamic stability domains of poly-sulfur moieties, which contain several atoms of sulfur per molecule. Mechanisms of electrooxidation of thiosulfate and of dibenzothiophene have been investigated. Under judiciously controlled experimental conditions, these electrode reactions proceed with 100% current efficiency at glassy carbon anodes. They provide a sound theoretical basis for dependable electroanalytical methods applicable to the determination of S/sub 2/O/sub 3//sup -/ and of dibenzothiophene in coal conversion process streams and products. The systematic search for specific reagents, amenable to the determination of sulfur contaminants by thermometric enthalpy titration and by direct injection enthalpimetry, was continued. 0.12% sulfide has been successfully determined by differential pulse polarography at a dropping mercury anode in scrubber water from a coal liquefaction process. Concentration levels of 1 ppM (or less) of sulfide were estimated in two gasifier condensate samples by the same method. Differential pulse voltammetry at a rotated glassy carbon disk anode was used to detect and determine quantitatively the presence of 0.1% dibenzothiophene in an SRC II stripper bottom product.

Jordan, J.

1980-01-01

124

A new process for H{sub 2}S removal and sulfur recovery from natural gas using heteropoly acid as absorbent  

SciTech Connect

A new liquid phase oxidation process employing heteropoly acids as absorbents for H{sub 2}S removal and sulfur recovery from natural gas was developed. The experiment was conducted in a chemo-absorption system consisting of 4 single-bubble absorption flasks in series, with the inlet gas H{sub 2}S concentrations ranging from 0-6400 mg/m{sup 3} . The effects of various operating conditions on hydrogen sulfide conversion were investigated and discussed. It was found that the heteropoly acid solution can be used to oxidize hydrogen sulfide in feeding gas into element sulfur and regenerated by suitable oxidants such as air, such as Fe{sup 3+}, Cl{sub 2}, O{sub 2}, NO{sub x} and so on. The success of the present investigation should lay a fundamental basis for the application of heteropoly compounds in pollution control and resource reclamation. 3 refs., 4 figs., 2 tabs.

Bao, X.; Wei, W.; Liu, L.; Wang, X. [Univ. of Petroleum, Beijing (China); Zhao, Y. [Tongji Univ., Shanghai (China)

1996-12-31

125

Experimental Behavior of Sulfur Under Primitive Planetary Differentiation Processes, the Sulfide Formations in Enstatite Meteorites and Implications for Mercury.  

NASA Technical Reports Server (NTRS)

Enstatite meteorites are the most reduced naturally-occuring materials of the solar system. The cubic monosulfide series with the general formula (Mg,Mn,Ca,Fe)S are common phases in these meteorite groups. The importance of such minerals, their formation, composition and textural relationships for understanding the genesis of enstatite chondrites (EC) and aubrites, has long been recognized (e.g. [1]). However, the mechanisms of formation of these sulfides is still not well constrained certainly because of possible multiple ways to produce them. We propose to simulate different models of formation in order to check their mineralogical, chemical and textural relevancies. The solubility of sulfur in silicate melts is of primary interest for planetary mantles, particularly for the Earth and Mercury. Indeed, these two planets could have formed, at least partly, from EC materials (e.g. [2, 3, 4]). The sulfur content in silicate melts depends on the melt composition but also on pressure (P), temperature (T) and oxygen fugacity fO2. Unfortunately, there is no model of general validity in a wide range of P-T-fO2-composition which describes precisely the evolution of sulfur content in silicate melts, even if the main trends are now known. The second goal of this study is to constrain the sulfur content in silicate melts under reducing conditions and different temperatures.

Malavergne, V.; Brunet, F.; Righter, K.; Zanda, B.; Avril, C.; Borensztajn, S.; Berthet, S.

2012-01-01

126

Thermodynamic characterization of metal dissolution and inhibitor adsorption processes in the low carbon steel/mimosa tannin/sulfuric acid system  

NASA Astrophysics Data System (ADS)

The corrosion rates in the presence of mimosa tannin as a low carbon steel corrosion inhibitor in sulfuric acid media, were measured by the weight loss method, in the range of temperatures from 20 to 60 °C. The Temkin, Frumkin and Freundlich isotherms were tested for their fit to the experimental data. The free energies and enthalpies for the adsorption process and the apparent activation energies, enthalpies and entropies of the dissolution process were determined. The fundamental thermodynamic functions were used to glean important information about the mimosa tannin inhibitory behavior. The results were explained in terms of chemical thermodynamics.

Martinez, Sanja; Stern, Ivica

2002-10-01

127

Molecular Structure of Sulfuric Acid  

NSDL National Science Digital Library

H2SO4 was discovered by alchemists and made from heating a compound of iron sulfate. In 1740, sulfuric acid was produced for commercial sale. Sulfuric acid is a very strong acid which is used in car batteries. The acid disassociates in water to give two protons and sulfate. This acid can destroy flesh and cause blindness. It was discovered in the 19th century that adding sulfuric acid to soil produces phosphorus, which is beneficial to plants; hence, sulfuric acid is used as a fertilizer in the form of super phosphate and ammonium sulfate. Sulfuric acid is also used to refine petroleum and process metals, and is found in paints and car batteries.

2002-08-15

128

Progress in the Los Alamos Scientific Laboratory program to develop thermochemical processes for hydrogen production. [Oxide-sulfate cycles; sulfuric acid cycles; bromide-sulfate cycles; sulfuric acid-sulfur cycles; hybrid cycles  

Microsoft Academic Search

The Los Alamos Scientific Laboratory Program to develop thermochemical processes for hydrogen production is based on attempts to develop criteria required of an ideal process and to search for types of thermochemical cycles that approximate these criteria. The advantages of reactions with large entropy changes have been demonstrated. The necessity for experimental verification of conceptual cycles has become apparent from

1976-01-01

129

Elucidating microbial processes in nitrate- and sulfate-reducing systems using sulfur and oxygen isotope ratios: The example of oil reservoir souring control  

NASA Astrophysics Data System (ADS)

Sulfate-reducing bacteria (SRB) are ubiquitous in anoxic environments where they couple the oxidation of organic compounds to the production of hydrogen sulfide. This can be problematic for various industries including oil production where reservoir "souring" (the generation of H 2S) requires corrective actions. Nitrate or nitrite injection into sour oil fields can promote SRB control by stimulating organotrophic nitrate- or nitrite-reducing bacteria (O-NRB) that out-compete SRB for electron donors (biocompetitive exclusion), and/or by lithotrophic nitrate- or nitrite-reducing sulfide oxidizing bacteria (NR-SOB) that remove H 2S directly. Sulfur and oxygen isotope ratios of sulfide and sulfate were monitored in batch cultures and sulfidic bioreactors to evaluate mitigation of SRB activities by nitrate or nitrite injection. Sulfate reduction in batch cultures of Desulfovibrio sp. strain Lac15 indicated typical Rayleigh-type fractionation of sulfur isotopes during bacterial sulfate reduction (BSR) with lactate, whereas oxygen isotope ratios in unreacted sulfate remained constant. Sulfur isotope fractionation in batch cultures of the NR-SOB Thiomicrospira sp. strain CVO was minimal during the oxidation of sulfide to sulfate, which had ?18O SO4 values similar to that of the water-oxygen. Treating an up-flow bioreactor with increasing doses of nitrate to eliminate sulfide resulted in changes in sulfur isotope ratios of sulfate and sulfide but very little variation in oxygen isotope ratios of sulfate. These observations were similar to results obtained from SRB-only, but different from those of NR-SOB-only pure culture control experiments. This suggests that biocompetitive exclusion of SRB took place in the nitrate-injected bioreactor. In two replicate bioreactors treated with nitrite, less pronounced sulfur isotope fractionation and a slight decrease in ?18O SO4 were observed. This indicated that NR-SOB played a minor role during dosing with low nitrite and that biocompetitive exclusion was the major process. The results demonstrate that stable isotope data can contribute unique information for understanding complex microbial processes in nitrate- and sulfate-reducing systems, and offer important information for the management of H 2S problems in oil reservoirs and elsewhere.

Hubert, Casey; Voordouw, Gerrit; Mayer, Bernhard

2009-07-01

130

Comparison of fixation and processing methods for hairless guinea pig skin following sulfur mustard exposure. (Reannouncement with new availability information)  

Microsoft Academic Search

Ten anesthetized hairless guinea pigs Crl:IAF(HA)BR were exposed to 10 pi of neat sulfur mustard (HD) in a vapor cup on their skin for 7 min. At 24 h postexposure, the guinea pigs were euthanatized and skin sections taken for histologic evaluation. The skin was fixed using either 10% neutral buffered formalin (NBF), McDowell Trump fixative (4CF-IG), Zenker`s formol-saline (Helly`s

M. A. Bryant; E. H. Braue Jr

1992-01-01

131

SULFUR POLYMER ENCAPSULATION.  

SciTech Connect

Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature degradation. These failures were caused by the internal stresses that result from changes in crystalline structure upon cooling of the material. By reacting elemental sulfur with organic polymers, the Bureau of Mines developed a product that successfully suppresses the solid phase transition and significantly improves the stability of the product. SPC, originally named modified sulfur cement, is produced from readily available, inexpensive waste sulfur derived from desulfurization of both flue gases and petroleum. The commercial production of SPC is licensed in the United States by Martin Resources (Odessa, Texas) and is marketed under the trade name Chement 2000. It is sold in granular form and is relatively inexpensive ({approx}$0.10 to 0.12/lb). Application of SPC for the treatment of radioactive, hazardous, and mixed wastes was initially developed and patented by Brookhaven National Laboratory (BNL) in the mid-1980s (Kalb and Colombo, 1985; Colombo et al., 1997). The process was subsequently investigated by the Commission of the European Communities (Van Dalen and Rijpkema, 1989), Idaho National Engineering Laboratory (Darnell, 1991), and Oak Ridge National Laboratory (Mattus and Mattus, 1994). SPC has been used primarily in microencapsulation applications but can also be used for macroencapsulation of waste. SPC microencapsulation has been demonstrated to be an effective treatment for a wide variety of wastes, including incinerator hearth and fly ash; aqueous concentrates such as sulfates, borates, and chlorides; blowdown solutions; soils; and sludges. It is not recommended for treatment of wastes containing high concentrations of nitrates because of potentially dangerous reactions between sulfur, nitrate, and trace quantities of organics. Recently, the process has been adapted for the treatment of liquid elemental mercury and mercury contaminated soil and debris.

KALB, P.

2001-08-22

132

Role of RIS/APC for manufacturing RFG/LSD. [Refinery Information Systems/Advanced Process Control, ReFormulated Gasoline/Low Sulfur Diesels  

SciTech Connect

Revolutionary changes in quality specifications (number, complexity, uncertainty, economic sensitivity) for reformulated gasolines (RFG) and low-sulfur diesels (LSD) are being addressed by powerful, new, computer-integrated manufacturing technology for Refinery Information Systems and Advanced Process Control (RIS/APC). This paper shows how the five active RIS/APC functions: performance measurement, optimization, scheduling, control and integration are used to manufacture new, clean fuels competitively. With current industry spending for this field averaging 2 to 3 cents/bbl crude, many refineries can capture 50 to 100 cents/bbl if the technology is properly employed and sustained throughout refining operations, organizations, and businesses.

Latour, P.R. (SETPOINT, Inc., Houston, TX (United States))

1994-01-01

133

Novel biotransformation process of podophyllotoxin to 4 ?-sulfur-substituted podophyllum derivates with anti-tumor activity by Penicillium purpurogenum Y.J. Tang.  

PubMed

According to the structure-function relationship of podophyllotoxin (PTOX) and its analogue of 4'- demethylepipodophyllotoxin (DMEP), the 4 ?-substitution of sulfur-containing heterocyclic compounds with a carbon-sulfur bond at 4 position of PTOX or DMEP is an essential modification direction for improving the anti-tumor activity. So, four novel 4 ?-sulfursubstituted podophyllum derivatives (i.e., 4? -(1,2,4-triazole-3-yl)sulfanyl-4-deoxy-podophyllotoxin (4-MT-PTOX), 4?-(1,3,4- thiadiazole-2-yl)sulfanyl-4-deoxy-podophyllotoxin (4-MTD-PTOX), 4?-(1,2,4-triazole-3-yl)sulfanyl-4-deoxy-4' -demethylepipodophyllotoxin (4-MT-DMEP), and 4?-(1,3,4-thiadiazole-2-yl)sulfanyl-4-deoxy-4'-demethylepipodophyllotoxin (4-MTD-DMEP)) were designed and then successfully biosynthesized in this work. In the novel sulfur-substituted biotransformation processes, PTOX and DMEP was linked with sulfur-containing compounds (i.e., 3-mercapto-1,2,4-triazole (MT) and 2-mercapto-1,3,4-thiadiazole (MTD)) at 4 position of cycloparaffin to produce 4-MT-PTOX (1), 4-MTD-PTOX (2), 4-MT-DMEP (3), and 4-MTD-DMEP (4) by Penicillium purpurogenum Y.J. Tang, respectively, which was screened out from Diphylleia sinensis Li (Hubei, China). All the novel compounds exhibited promising in vitro bioactivity, especially 4-MT-PTOX (1). Compared with etoposide (i.e., a 50 % effective concentration [EC(50)] of 25.72, 167.97, and 1.15 M), the EC(50) values of 4-MT-PTOX (1) against tumor cell line BGC-823, A549 and HepG2 (i.e., 0.28, 0.76, and 0.42 M) were significantly improved by 91, 221 and 2.73 times, respectively. Moreover, the EC(50) value of 4-MT-PTOX (1) against the normal human cell line HK-2 (i.e., 182.4 ?M) was 19 times higher than that of etoposide (i.e., 9.17 ?M). Based on the rational design, four novel 4 ?-sulfur-substituted podophyllum derivatives with superior in vitro anti-tumor activity were obtained for the first time. The correctness of structure-function relationship and rational drug design was strictly demonstrated by the in vitro biological activity tests. PMID:22214458

Bai, J-K; Zhao, W; Li, H-M; Tang, Y-J

2012-01-01

134

A novel approach to realize SANI process in freshwater sewage treatment--Use of wet flue gas desulfurization waste streams as sulfur source.  

PubMed

SANI (Sulfate reduction, Autotrophic denitrification and Nitrification Integrated) process has been approved to be a sludge-minimized sewage treatment process in warm and coastal cities with seawater supply. In order to apply this sulfur-based process in inland cold areas, wet flue gas desulfurization (FGD) can be simplified and integrated with SANI process, to provide sulfite as electron carrier for sulfur cycle in sewage treatment. In this study, a lab-scale system of the proposed novel process was developed and run for over 200 days while temperature varied between 30 and 5 °C, fed with synthetic FGD wastewaters and sewage. The sulfite-reducing upflow anaerobic sludge bed (SrUASB) reactor, as the major bioreactor of the system, removed 86.9% of organics while the whole system removed 94% of organics even when water temperature decreased to around 10 °C. The bactericidal effect of sulfite was not observed in the SrUASB reactor, while thiosulfate was found accumulated under psychrophilic conditions. The sludge yield of the SrUASB reactor was determined to be 0.095 kg VSS/kg COD, higher than of sulfate reduction process but still much lower than of conventional activated sludge processes. The dominant microbes in the SrUASB reactor were determined as Lactococcus spp. rather than sulfate-reducing bacteria, but sulfite reduction still contributed 85.5% to the organic carbon mineralization in this reactor. Ammonia and nitrate were effectively removed in the aerobic and anoxic filters, respectively. This study confirms the proposed process was promising to achieve sludge-minimized sewage treatment integrating with flue gas desulfurization in inland and cold areas. PMID:23886546

Jiang, Feng; Zhang, Liang; Peng, Guo-Liang; Liang, Si-Yun; Qian, Jin; Wei, Li; Chen, Guang-Hao

2013-10-01

135

Development of enhanced sulfur rejection processes. Third quarterly technical progress report, April 1, 1993--June 31, 1993  

SciTech Connect

Conclusions: Release analyses of Pittsburgh No. 8 and Illinois No. 6 coals show that the {minus}28 mesh size fraction is fine enough to liberate ash and pyrite. Galvanic coupling with sacrificial anodes such as zinc, manganese and aluminum can effectively lower the potential of pyrite. This effect is more significant at pH 4.6 than at pH 9.2. The most negative pyrite potential is achieved when the surface area ratio of anode to pyrite is approximately 4:1. When coupled with pyrite at pH 9.2, the zinc anode exhibited unique potential vs time behavior which is different from that observed with manganese and aluminum. This is believed to be related to the build- up and break-down of zinc hydroxides on the surface. Voltammograms of pyrite at pH 9.2 and 4.6 demonstrated that pyrite surfaces can be significantly changed by galvanic coupling with sacrificial anodes. In flotation tests, metal powders were used as galvanic contactors to reduce the potential and depress pyrite. The potenial may be low enough to remove sulfur species from the surface. Stirred solutions are preferred for the removal of oxidized sulfur species by galvanic coupling; oxygen in solution must to be depleted prior to the addition of sacrificial anodes to effectively lower the pyrite potential. Microflotation studies show that zinc, manganese and iron all depress pyrite. Zinc appears to be the most effective, followed by manganese and then iron. Voltammetry studies indicated that coupling pyrite with zinc, manganese and aluminum reduces and desorbs hydrophobic sulfur products on the surface of pyrite.

Yoon, R.H.; Luttrell, G.H.; Adel, G.T.; Richardson, P.E.

1993-10-12

136

Uses of lunar sulfur  

NASA Technical Reports Server (NTRS)

Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical, and biochemical properties. Although known abundances on the Moon are limited (approximately 0.1 percent in mare soils), sulfur is relatively extractable by heating. Coproduction of sulfur during oxygen extraction from ilmenite-rich mare soils could yield sulfur in masses up to 10 percent of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource.

Vaniman, D.; Pettit, D.; Heiken, G.

1992-01-01

137

Lunar Sulfur Capture System  

NASA Technical Reports Server (NTRS)

The Lunar Sulfur Capture System (LSCS) protects in situ resource utilization (ISRU) hardware from corrosion, and reduces contaminant levels in water condensed for electrolysis. The LSCS uses a lunar soil sorbent to trap over 98 percent of sulfur gases and about two-thirds of halide gases evolved during hydrogen reduction of lunar soils. LSCS soil sorbent is based on lunar minerals containing iron and calcium compounds that trap sulfur and halide gas contaminants in a fixed-bed reactor held at temperatures between 250 and 400 C, allowing moisture produced during reduction to pass through in vapor phase. Small amounts of Earth-based polishing sorbents consisting of zinc oxide and sodium aluminate are used to reduce contaminant concentrations to one ppm or less. The preferred LSCS configuration employs lunar soil beneficiation to boost concentrations of reactive sorbent minerals. Lunar soils contain sulfur in concentrations of about 0.1 percent, and halogen compounds including chlorine and fluorine in concentrations of about 0.01 percent. These contaminants are released as gases such as H2S, COS, CS2,HCl, and HF during thermal ISRU processing with hydrogen or other reducing gases. Removal of contaminant gases is required during ISRU processing to prevent hardware corrosion, electrolyzer damage, and catalyst poisoning. The use of Earth-supplied, single-use consumables to entirely remove contaminants at the levels existing in lunar soils would make many ISRU processes unattractive due to the large mass of consumables relative to the mass of oxygen produced. The LSCS concept of using a primary sorbent prepared from lunar soil was identified as a method by which the majority of contaminants could be removed from process gas streams, thereby substantially reducing the required mass of Earth-supplied consumables. The LSCS takes advantage of minerals containing iron and calcium compounds that are present in lunar soil to trap sulfur and halide gases in a fixedbed reactor downstream of an in-ISRU process such as hydrogen reduction. The lunar-soil-sorbent trap is held at a temperature significantly lower than the operating temperature of the hydrogen reduction or other ISRU process in order to maximize capture of contaminants, but is held at a high enough temperature to allow moisture to pass through without condensing. The lunar soil benefits from physical beneficiation to remove ultrafine particles (to reduce pressure drop through a fixed bed reactor) and to upgrade concentrations of iron and/or calcium compounds (to improve reactivity with gaseous contaminants).

Berggren, Mark; Zubrin, Robert; Bostwick-White, Emily

2013-01-01

138

Development of a novel process for the biological conversion of H2S and methanethiol to elemental sulfur.  

PubMed

The feasibility of anaerobic treatment of wastewater containing methanethiol (MT), an extremely volatile and malodorous sulfur compound, was investigated in lab-scale bioreactors. Inoculum biomass originating from full-scale anaerobic wastewater treatment facilities was used. Several sludges, tested for their ability to degrade MT, revealed the presence of organisms capable of metabolizing MT as their sole source of energy. Furthermore, batch tests were executed to gain a better understanding of the inhibition potential of MT. It was found that increasing MT concentrations affected acetotrophic organisms more dramatically than methylotrophic organisms. Continuous reactor experiments, using two lab-scale upflow anaerobic sludge bed (UASB) reactors (R1 and R2), aimed to determine the maximal MT load and the effect of elevated sulfide concentrations on MT conversion. Both reactors were operated at a hydraulic retention time (HRT) of about 7 hours, a temperature of 30 degrees C, and a pH of between 7.3 and 7.6. At the highest influent MT concentration applied, 14 mM in R1, corresponding to a volumetric loading rate of about 50 mM MT per day, 87% of the organic sulfur was recovered as hydrogen sulfide (12.2 mM) and the remainder as volatile organic sulfur compounds (VOSCs). Upon decreasing the HRT to 3.5 to 4.0 h at a constant MT loading rate, the sulfide concentration in the reactor decreased to 8 mM and MT conversion efficiency increased to values near 100%. MT conversion was apparently inhibited by the high sulfide concentrations in the reactor. The specific MT degradation rate, as determined after 120 days of operation in R1, was 2.83 +/- 0.27 mmol MT g VSS(-1) day(-1). During biological desulfurization of liquid hydrocarbon phases, such as with liquefied petroleum gas (LPG), the combined removal of hydrogen sulfide and MT is desired. In R2, the simultaneous addition of sodium sulfide and MT was therefore studied and the effect of elevated sulfide concentrations was investigated. The addition of sodium sulfide resulted in enhanced disintegration of sludge granules, causing significant washout of biomass. Additional acetate, added to stimulate growth of methanogenic bacteria to promote granulation, was hardly converted at the termination of the experimental period. PMID:12569619

Sipma, Jan; Janssen, Albert J H; Pol, Look W Hulshoff; Lettinga, Gatze

2003-04-01

139

Electrochemical characteristics with the addition of carbon nanotubes and the manufacturing process for sulfur cathode in the Li/S cell.  

PubMed

Carbon nanotubes (CNTs) were purified using acid solution, and CNT-sulfur composite powder was prepared via precipitation, using the purified CNTs. In addition, the effect of the purified CNTs (PUCNTs) on the electrochemical performance of the Li/S cell was investigated. After the purification, almost all the impurities in the as-synthesized CNTs (ASCNTs) were removed, and the dispersibility of the CNTs was improved. On the other hand, the concentration of the structural defects and of the disordered structures in the PUCNTs was increased due to the surface oxidation of the tubes during acid treatment. In the case of the PUCNT-S composite powder, the outer wall of the tubes was well covered with sulfur, as opposed to the tubes in the ASCNT-S composite powder. The Li/S cell containing ASCNT-S composite cathode showed a large voltage decrease and a 680 mAh/g capacity during the first discharge process. The Li/S cell with PUCNT-S composite cathode, however, showed a higher discharge capacity and better cycle performance than the cell with ASCNT-S composite cathode. The electrochemical performance of the Li/S cell was improved for the PUCNT-S composite cathode using the CNTs purified by acid treatment. PMID:22121610

Choi, Young Jin; Kim, Jin Hwa; Kim, Ki Won; Ahn, Hyo Jun; Nam, Tae Hyun; Cho, Kwon Koo

2011-07-01

140

Chemical and microbiological tests to simulate sulfuric acid corrosion of polymer-modified concrete  

Microsoft Academic Search

In certain industrial activities sulfuric acid is used during the production process, which may cause degradation of concrete structures. Another important phenomenon where sulfuric acid is responsible for concrete corrosion is biogenic sulfuric acid corrosion, which occurs often in sewer systems. Because previous investigations have already pointed out the difference between purely chemical sulfuric acid corrosion and biogenic sulfuric acid

J Monteny; N De Belie; E Vincke; W Verstraete; L Taerwe

2001-01-01

141

Production of sulfur from sulfur dioxide obtained from flue gas  

SciTech Connect

This patent describes a regenerable process for recovery of elemental sulfur from a gas containing sulfur dioxide comprising the steps of: contacting the gas with an aqueous, alkaline reaction medium containing sodium sulfite in concentration sufficient so that a slurry containing solid sodium sulfide is formed to react sulfur dioxide with sodium sulfite to form a solution containing dissolved sodium pyrosulfite and sodium sulfite; separating sulfur dioxide from the solution produced to leave a residual mixture containing water, sodium sulfite and a sodium pyrosulfite, the amount of sulfur dioxide separated being equal to about one-third the amount of sulfur dioxide which reacted with sodium sulfite; adding, in substantial absence of air, sufficient water and sodium bicarbonate to the residual mixture to react with the dissolved sodium pyrsulfide and form a slurry of solid sodium sulfite suspended in the resulting aqueous, alkaline reaction medium and gaseous carbon dioxide; separating the gaseous carbon dioxide; separating the solid sodium sulfite from the aqueous alkaline reaction medium and recycling the separated reaction medium; reducing the separated sodium sulfite to sodium sulfide; adding the sodium sulfide to an aqueous reaction medium containing sodium bicarbonate and, in the substantial absence of air, carbonating the resulting mixture with the gaseous carbon dioxide to form a slurry of solid particles of sodium bicarbonate dispersed in an aqueous reactor medium containing sodium bicarbonate, along with a gas composed primarily of hydrogen sulfide.

Miller, R.

1989-06-06

142

Speciation of sulfur in the insoluble organic matter from carbonaceous chondrites by XANES spectroscopy  

E-print Network

Speciation of sulfur in the insoluble organic matter from carbonaceous chondrites by XANES-edge XANES aqueous alteration carbonaceous chondrites oxidation sulfur speciation Sulfur speciation speciation was detected. This suggests tenuous oxidation processes and a low-temperature aqueous alteration

143

MULTIPLE SULFUR ISOTOPE FRACTIONATIONS IN BIOLOGICAL SYSTEMS: A CASE STUDY WITH SULFATE REDUCERS  

E-print Network

MULTIPLE SULFUR ISOTOPE FRACTIONATIONS IN BIOLOGICAL SYSTEMS: A CASE STUDY WITH SULFATE REDUCERS*, DONALD E. CANFIELD**, and KIRSTEN S. HABICHT** ABSTRACT. Multiple sulfur isotope measurements of sulfur disproportionation indicate that different types of metabolic processes impart differ- ent multiple isotope

Kaufman, Alan Jay

144

A New Use for High-Sulfur Coal  

NASA Technical Reports Server (NTRS)

New process recovers some of economic value of high-sulfur coal. Although high-sulfur content is undesirable in most coal-utilization schemes (such as simple burning), proposed process prefers high-sulfur coal to produce electrical power or hydrogen. Potential exists for widespread application in energy industry.

Lawson, D. D.; England, C.

1982-01-01

145

A primer on sulfur for the planetary geologist  

NASA Technical Reports Server (NTRS)

Sulfur has been proposed as the dominant composition for the volcanic material on Io. Sulfur is a complex element which forms many intramolecular and intermolecular allotropes exhibiting a variety of physical properties. Cyclo-S8 sulfur is the most abundant and stable molecular form. The important molecular species within liquid sulfur change in concentration with temperature. Concentrations of the allotropes control the physical properties of the melt. Discontinuities in density, viscosity, and thermal properties reflect the polymerization process within liquid sulfur. Variations in the melting point are related to autodissociation of the liquid. Many solids forms of sulfur have been identified but only orthorhombic alpha and monoclinic beta sulfur, both composed of cyclo-S8 sulfur, are stable under terrestrial conditions. Physical properties of solid sulfur are dependent on the allotrope and, in some cases, the thermal history. Three natural terrestrial sulfur flows are described: (1) Siretoko-Iosan, Japan; (2) Volcan Azufre, Galapagos Islands; and (3) Mauna Loa, Hawaii. All of the flows are associated with fumarolic areas and are considered to have formed by the melting and mobilization of sulfur deposits. Surface textures of the flows indicate a behavior of molten sulfur similar to that of silicate lava. Channels, rivulets, and lobate edges were described for the flows. The solidification of man-made sulfur flows formed as part of the Frasch mining process by which sulfur is removed from the subsurface in a liquid state is described.

Theilig, E.

1982-01-01

146

Elemental sulfur in Eddy County, New Mexico  

USGS Publications Warehouse

Sulfur has been reported in Eddy County, N. Mex., in rocks ranging from Silurian to Holocene in age at depths of 0-15,020 feet. Targets of present exploration are Permian formations in the Delaware Basin and northwest shelf areas at depths of less than 4,000 feet. Most of the reported sulfur occurrences in the shelf area are in the 'Abo' (as used by some subsurface geologists), Yeso, and San Andres Formations and the Artesia Group. Sulfur deposition in the dense dolomites of the 'Abo,' Yeso, and San Andres Formations is attributed to the reduction of ionic sulfate by hydrogen sulfide in formation waters in zones of preexisting porosity and permeability. A similar origin accounts for most of the sulfur deposits in the formations of the Artesia Group, but some of the sulfur in these formations may have originated in place through the alteration of anhydrite to carbonate and sulfur by the metabolic processes of bacteria in the presence of hydrocarbons. Exploration in the Delaware Basin area is directed primarily toward the Castile Formation. Sulfur deposits in the Castile Formation are found in irregular masses of cavernous brecciated secondary carbonate rock enveloped by impermeable anhydrite. The carbonate masses, or 'castiles,' probably originated as collapse features resulting from subsurface solution and upward stopping. Formation of carbonate rock and sulfur in the castiles is attributed to the reduction of brecciated anhydrite by bacteria and hydrocarbons in the same process ascribed to the formation of carbonate and sulfur in the caprocks of salt domes.

Hinds, Jim S.; Cunningham, Richard R.

1970-01-01

147

Estimating Effects of Atmospheric Deposition and Peat Decomposition Processes on Mercury and Sulfur Accumulation and Retention in Northern Peatlands, Minnesota  

NASA Astrophysics Data System (ADS)

Northern peatland ecosystems play an important role in mercury (Hg) and sulfur (S) co-cycling. Peatlands are sinks for total Hg and sources for methyl Hg through the activity of sulfate-reducing bacteria. These ecosystems are vulnerable to environmental change, and projected changes in climate for the north-central U.S. have the potential to affect Hg and S stores and cycling in the subsurface, which may stimulate the release of bioaccumulative methyl Hg to receiving water bodies. SPRUCE (Spruce and Peatland Responses under Climate and Environmental change experiment) is an interdisciplinary study of the effects of temperature and enriched carbon dioxide on the responses of northern peatland ecosystems at the Marcell Experimental Forest, Minnesota. In the first year of SPRUCE, we are investigating Hg and S accumulation rates in 12-m diameter experimental plots on a black spruce bog before peatland heating experiments start in 2014. Understanding Hg and S accumulation rates and their retention mechanisms in the subsurface are needed in order to reconstruct historical trends in Hg and S deposition, and predict peatland responses to climate change. In this study, we will attempt to separate the effects of atmospheric deposition vs peat humification on Hg and S retention. As such, peat cores were sampled from sixteen experimental SPRUCE plots in August 2012. These 'Time 0' peat subsamples have been analyzed for total Hg, methyl Hg and total S, and bulk density as a function of depth (<2 m). In addition, peat subsamples have been analyzed for 14C and 13C to determine the age of peat and derive peat, Hg and S accumulation rates. Our preliminary results indicate that both total and methyl Hg, and total S concentrations reached the peak value in the 20-40 cm peat section, which is the transition zone between transiently oxidized acrotelm and permanently saturated anaerobic catotelm. Total and methyl Hg concentrations were several times lower in deeper profiles (>50 cm), and showed lower variability. Changes in Hg and S over depth seem to be associated with the variation in humification of soil organic matter. These findings are critical to better conceptualization as well as parameterization of models that project how climate change will affect the accumulation, cycling, and export of toxic methylmercury from peatlands.

Furman, O.; Nater, E.; Toner, B. M.; Sebestyen, S. D.; Tfaily, M. M.; Chanton, J.; Kolka, R. K.

2013-12-01

148

Thiophenic Sulfur Compounds Released During Coal Pyrolysis.  

PubMed

Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography-mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

2013-06-01

149

Sulfuric acid poisoning  

MedlinePLUS

Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and ... or mucous membranes. This article discusses poisoning from sulfuric acid. This is for information only and not for ...

150

Sulfur and sulfur compounds in plant defence.  

PubMed

The multiplicity of chemical structures of sulfur containing compounds, influenced in part by the element's several oxidation states, directly results in diverse modes of action for sulfur-containing natural products synthesized as secondary metabolites in plants. Sulfur-containing natural products constitute a formidable wall of defence against a wide range of pathogens and pests. Steady progress in the development of new technologies have advanced research in this area, helping to uncover the role of such important plant defence molecules like endogenously-released elemental sulphur, but also deepening current understanding of other better-studied compounds like the glucosinolates. As studies continue in this area, it is becoming increasingly evident that sulfur and sulfur compounds play far more important roles in plant defence than perhaps previously suspected. PMID:22545416

Nwachukwu, Ifeanyi D; Slusarenko, Alan J; Gruhlke, Martin C H

2012-03-01

151

FEASIBILITY OF PRODUCING ELEMENTAL SULFUR FROM MAGNESIUM SULFITE  

EPA Science Inventory

The report gives results of a study to extend potential applications of MgO flue gas desulfurization processes by allowing the sulfur to be recovered as elemental sulfur as well as sulfuric acid. The study considered the feasibility of combining the exothermic SO2 reduction react...

152

World sulfur production: As of Jan. 1, 1994  

SciTech Connect

The article consists of a table which lists company and location, source of sulfur, type of process used, design capacity, and sulfur production for 42 countries. Sources of sulfur include refinery gases, natural gas, acid gases, crude oil, shale gas, oil sands, coke oven gas, and hydrogen sulfide.

Not Available

1994-06-13

153

Sulfur tolerant anode materials  

SciTech Connect

The goal of this program is the development of a molten carbonate fuel cell (MCFC) anode which is more tolerant of sulfur contaminants in the fuel than the current state-of-the-art nickel-based anode structures. This program addresses two different but related aspects of the sulfur contamination problem. The primary aspect is concerned with the development of a sulfur tolerant electrocatalyst for the fuel oxidation reaction. A secondary issue is the development of a sulfur tolerant water-gas-shift reaction catalyst and an investigation of potential steam reforming catalysts which also have some sulfur tolerant capabilities. These two aspects are being addressed as two separate tasks.

Not Available

1987-02-01

154

Biochemistry of sulfur  

SciTech Connect

This book presents information on the following topics: the chemistry of sulfur; the oxidation states of sulfur; the reduction of sulfate and the oxidation of sulfide; the sulfur cycle; oxidation of inorganic sulfide; the metabolism and functions of methionine; taurine and the oxidative metabolism of cysteine; thiols, disulfides, and thioesters; thioethers; thiamine; biotin; sulfates; inherited disorders of sulfur metabolism; cystinuria; sulfur and the metabolism of xenobiotics; general aspects of xenobiotic metabolism; glutathione and sulfation of xenobiotics; and metabolic activation as a result of sulfate conjugation.

Huxtable, R.J.; LaFranconi, W.M.

1986-01-01

155

Sulfur tolerant anode materials  

SciTech Connect

The goal of this program is the development of a molten carbonate fuel cell (MCFC) anode which is more tolerant of sulfur contaminants in the fuel than the current state-of-the-art nickel-based anode structures. This program addresses two different but related aspects of the sulfur contamination problem. The primary aspect is concerned with the development of a sulfur tolerant electrocatalyst for the fuel oxidation reaction. A secondary issue is the development of a sulfur tolerant water-gas-shift reaction catalyst and an investigation of potential steam reforming catalysts which also have some sulfur tolerant capabilities. These two aspects are being addressed as two separate tasks.

Not Available

1988-05-01

156

CATALYST EVALUATION FOR A SULFUR DIOXIDE-DEPOLARIZED ELECTROLYZER  

SciTech Connect

Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. Testing examined the activity and stability of platinum and palladium as the electrocatalyst for the SDE in sulfuric acid solutions. Cyclic and linear sweep voltammetry revealed that platinum provided better catalytic activity with much lower potentials and higher currents than palladium. Testing also showed that the catalyst activity is strongly influenced by the concentration of the sulfuric acid electrolyte.

Hobbs, D; Hector Colon-Mercado, H

2007-01-31

157

Definition of Non-Conventional Sulfur Utilization in Western Kazakhstan for Sulfur Concrete (Phase 1)  

SciTech Connect

Battelle received a contract from Agip-KCO, on behalf a consortium of international oil and gas companies with exploration rights in the North Caspian Sea, Kazakhstan. The objective of the work was to identify and help develop new techniques for sulfur concrete products from waste, by-product sulfur that will be generated in large quantitites as drilling operations begin in the near future. BNL has significant expertise in the development and use of sulfur concrete products and has direct experience collaborating with the Russian and Kazakh partners that participated. Feasibility testing was successfully conducted for a new process to produce cost-effective sulfur polymer cement that has broad commerical applications.

Kalb, Paul

2007-05-31

158

Design and development of a novel gas desulfurization process using hollow fiber membranes to stimulate the utilization of high sulfur Ohio coal. Final report  

SciTech Connect

The objective of this proposed research was to carry out a detailed theoretical and experimental study of SO{sub 2} absorption in bench-scale hollow fiber absorbers (HFAs) under conditions representative of industrial flue gas desulfurization, and to use this knowledge to develop design criteria necessary for replacing conventional packed towers with industrial scale HFAS. If the use of high sulfur coal is ever to come to fruition, we must strive to explore new technologies which surpass the performance of existing systems. The precise objectives of this research were as follows: Construct a benchscale HFA module apparatus for experimental testing. Investigate the effect of important process parameters on HFA module performance (i.e. its ability to remove SO{sub 2}). Obtain correlations for predicting the mass transfer coefficient (a direct reflection of module performance) for SO{sub 2} removal based on the experimental results develop a mathematical model, design criteria, and operating condition guidelines to produce optimum HFA module performance in desulfurization applications

LeBlanc, S.E.; Varanasi, S.

1990-01-01

159

Sulfur isotopic systematics of granitoids from southwestern New Brunswick, Canada: implications for magmatic-hydrothermal processes, redox conditions, and gold mineralization  

Microsoft Academic Search

Bulk ?\\u000a 34Srock values, sulfur contents, and magnetic susceptibility were determined for 12 gold-related granitoid intrusions in southwestern\\u000a New Brunswick, the Canadian Appalachians. The sulfur isotope compositions of sulfide minerals in some of the granitoid samples\\u000a were also analyzed. This new dataset was used to characterize two distinctive groups of granitoids: (1) a Late Devonian granitic\\u000a series (GS) and (2)

Xue-Ming Yang; David R. Lentz

2010-01-01

160

An integrated biodesulfurization process, including inoculum preparation, desulfurization and sulfate removal in a single step, for removing sulfur from oils.  

SciTech Connect

BACKGROUND: A single-stage reactor, in which the growth of bacterial culture, induction of desulfurizing enzymes, and desulfurization reaction are carried out in a single step, was adopted to investigate desulfurization of DBT at high cell densities. IGTS8 was used as the biocatalyst. Optimal condition for the bacterial growth and DBT desulfurization were also investigated. RESULTS: Optimization of fermentation conditions was necessary to obtain high cell densities including controlling accumulation of acetate. Under optimal operating conditions, the maximum OD600 was measured to be 26.6 at 118 h of cultivation. When biodesulfurization of DBT in model oil with a high cell density culture of IGTS8 was investigated, accumulation of sulfate was found to limit the extent of desulfurization. A sulfate removal step was added to obtain a single-stage integrated biodesulfurization process. Sulfate removal was achieved via an aqueous bleed stream and use of a separation unit to recycle the organic phase. CONCLUSION : A proof of principle of a complete system capable of biocatalyst growth, induction, desulfurization and by-product separation was demonstrated. This system enables simplification of the biodesulfurization process and has potential to lower the operating cost of the bioprocess.

Tangaromsuk, Jantana [ORNL; Borole, Abhijeet P [ORNL; Kruatrachue, Maleeya [Mahidol University; Pokethitiyook, Prayad [PTT Research and Technical Institute

2008-01-01

161

Neutralization and biodegradation of sulfur mustard. Final report, October 1995-June 1996  

SciTech Connect

The chemical warfare agent sulfur mustard was hydrolyzed to products that were biologically mineralized in sequencing batch reactors seeded with activated sludge. Greater than 90% carbon removal was achieved using laboratory scale bioreactors processing hydrolyzed munitions grade sulfur mustard obtained directly from the U.S. Chemical Stockpile. The bioreactor effluent was nontoxic and contained no detectable sulfur mustard or priority pollutants. The sulfur mustard hydrolysis biodegradation process has potential application to the congressionally mandated disposal of sulfur mustard stockpiles.

Harvey, S.P.; Szafraniec, L.L.; Beaudry, W.T.; Earley, J.T.; Irvine, R.L.

1997-02-01

162

Implications for eruptive processes as indicated by sulfur dioxide emissions from Kilauea Volcano, Hawai'i, 1979-1997  

USGS Publications Warehouse

Ki??lauea Volcano, Hawai'i, currently hosts the longest running SO2 emission-rate data set on the planet, starting with initial surveys done in 1975 by Stoiber and his colleagues. The 17.5-year record of summit emissions, starting in 1979, shows the effects of summit and east rift eruptive processes, which define seven distinctly different periods of SO2 release. Summit emissions jumped nearly 40% with the onset (3 January 1983) of the Pu'u 'O??'o??-Ku??paianaha eruption on the east rift zone (ERZ). Summit SO2 emissions from Ki??lauea showed a strong positive correlation with short-period, shallow, caldera events, rather than with long-period seismicity as in more silicious systems. This correlation suggests a maturation process in the summit magma-transport system from 1986 through 1993. During a steady-state throughput-equilibrium interval of the summit magma reservoir, integration of summit-caldera and ERZ SO2 emissions reveals an undegassed volume rate of effusion of 2.1 ?? 105 m3/d. This value corroborates the volume-rate determined by geophysical methods, demonstrating that, for Ki??lauea, SO2 emission rates can be used to monitor effusion rate, supporting and supplementing other, more established geophysical methods. For the 17.5 years of continuous emission rate records at Ki??lauea, the volcano has released 9.7 ?? 106 t (metric tonnes) of SO2, 1.7 ?? 106 t from the summit and 8.0 ?? 106 t from the east rift zone. On an annual basis, the average SO2 release from Ki??lauea is 4.6 ?? 105 t/y, compared to the global annual volcanic emission rate of 1.2 ?? 107 t/y. ?? 2001 Elsevier Science B.V. All rights reserved.

Sutton, A.J.; Elias, T.; Gerlach, T.M.; Stokes, J.B.

2001-01-01

163

Superior electrochemical performance of sulfur/graphene nanocomposite material for high-capacity lithium-sulfur batteries.  

PubMed

Sulfur/graphene nanocomposite material has been prepared by incorporating sulfur into the graphene frameworks through a melting process. Field-emission scanning electron microscope analysis shows a homogeneous distribution of sulfur in the graphene nanosheet matrix. The sulfur/graphene nanocomposite exhibits a super-high lithium-storage capacity of 1580?mA h?g(-1) and a satisfactory cycling performance in lithium-sulfur cells. The enhancement of the reversible capacity and cycle life could be attributed to the flexible graphene nanosheet matrix, which acts as a conducting medium and a physical buffer to cushion the volume change of sulfur during the lithiation and delithiation process. Graphene-based nanocomposites can significantly improve the electrochemical performance of lithium-sulfur batteries. PMID:22454319

Wang, Bei; Li, Kefei; Su, Dawei; Ahn, Hyojun; Wang, Guoxiu

2012-06-01

164

Unsteady diagenetic processes and sulfur biogeochemistry in tropical deltaic muds: Implications for oceanic isotope cycles and the sedimentary record  

NASA Astrophysics Data System (ADS)

Sedimentary S cycling is usually conceptualized and interpreted within the context of steadily accreting (1-D) transport-reaction regimes. Unsteady processes, however, are common in many sedimentary systems and can result in dramatically different S reaction balances and diagenetic products than steady conditions. Globally important common examples include tropical deltaic topset and inner shelf muds such as those extending from the Amazon River ˜1600 km along the Guianas coast of South America. These deposits are characterized by episodic reworking of the surface seabed over vertical depths of ˜0.1-3 m. Reworked surface sediments act as unsteady, suboxic batch reactors, unconformably overlying relict anoxic, often methanic deposits, and have diagenetic properties largely decoupled from net accumulation of sediment. Despite well-oxygenated water and an abundant reactive organic matter supply, physical disturbance inhibits macrofauna, and benthic communities are dominated by microbial biomass across immense areas. In the surficial suboxic layer, molecular biological analyses, tracer experiments, sediment C/S/Fe compositions, and ? 34S, ? 18O of pore water SO42- indicate close coupling of anaerobic C, S, and Fe cycles. ? 18O- SO42- can increase by 2-3‰ during anaerobic recycling without net change in ? 34S- SO42-, demonstrating SO42- reduction coupled to complete anaerobic reoxidation to SO42- and a ? 18O- SO42- reduction + reoxidation fractionation factor?12‰ (summed magnitudes). S reoxidation must be coupled to Fe-oxide reduction, contributing to high dissolved Fe 2+ (˜1 mM) and Fe mobilization-export. The reworking of Amazon-Guianas shelf muds alone may isotopically alter ? 18O- SO42- equivalent in mass to?25% of the annual riverine delivery of SO42- to the global ocean. Unsteady conditions result in preservation of unusually heavy ? 34S isotopic compositions of residual Cr reducible S, ranging from 0‰ to >30‰ in physically reworked deposits. In contrast, bioturbated facies adjacent to physically reworked regions accumulate isotopically light S (? 34S to -20‰) in otherwise similar decomposition regimes. The isotopic patterns of both physically and biologically reworked regions can be simulated with simple diagenetic models. Heavy S isotopic signatures are largely a consequence of unsteady diffusion and progressive anaerobic burndown into underlying deposits, whereas isotopically depleted bioturbated deposits predominantly reflect biogenic diffusive scaling and isotopic distillation/diffusive pumping associated with reoxidation in burrow walls immediately adjacent to reduced zones. The S isotopic transition from unsteady physically controlled regions of the Amazon delta moving laterally into bioturbated facies mimics the transition of S isotopic patterns temporally in the geologic record during the rise of bioturbation. No special role for S disproportionation is required to explain these differences. The potential role of unsteady, suboxic diagenesis and dynamic reworking of sediments has been largely ignored in models of the evolution of surficial elemental cycling and interpretations of the geologic record.

Aller, Robert C.; Madrid, Vanessa; Chistoserdov, Andrei; Aller, Josephine Y.; Heilbrun, Christina

2010-08-01

165

Economic feasibility of biochemical processes for the upgrading of crudes and the removal of sulfur, nitrogen, and trace metals from crude oil -- Benchmark cost establishment of biochemical processes on the basis of conventional downstream technologies. Final report FY95  

SciTech Connect

During the past several years, a considerable amount of work has been carried out showing that microbially enhanced oil recovery (MEOR) is promising and the resulting biotechnology may be deliverable. At Brookhaven National Laboratory (BNL), systematic studies have been conducted which dealt with the effects of thermophilic and thermoadapted bacteria on the chemical and physical properties of selected types of crude oils at elevated temperatures and pressures. Current studies indicate that during the biotreatment several chemical and physical properties of crude oils are affected. The oils are (1) emulsified; (2) acidified; (3) there is a qualitative and quantitative change in light and heavy fractions of the crudes; (4) there are chemical changes in fractions containing sulfur compounds; (5) there is an apparent reduction in the concentration of trace metals; and (6) the qualitative and quantitative changes appear to be microbial species dependent; and (7) there is a distinction between biodegraded and biotreated oils. The downstream biotechnological crude oil processing research performed thus far is of laboratory scale and has focused on demonstrating the technical feasibility of downstream processing with different types of biocatalysts under a variety of processing conditions. Quantitative economic analysis is the topic of the present project which investigates the economic feasibility of the various biochemical downstream processes which hold promise in upgrading of heavy crudes, such as those found in California, e.g., Monterey-type, Midway Sunset, Honda crudes, and others.

Premuzic, E.T.

1996-08-01

166

[Sulfur metabolism and its regulation in plants].  

PubMed

Sulfur, one of the vital macroelements, is present in nature in several redox forms (S(+VI), S(+IV), S(+II), S0). In most organic compounds sulfur is present in the reduced form (S(-II)), while most inorganic sulfur is oxidized, in a form of sulfate (S(+VI)). Animals and humans can incorporate only the organic forms of sulfur, present in sulfur-containing amino acids. Plants, most bacteria and fungi are able to uptake inorganic sulfate, gradually reduce it and assimilate it into variety of organic compounds. Knowledge of the regulatory mechanisms of this process is a key factor for understanding relationships between availability of sulfur source and plant growth and development, their resistance to environmental stresses and nutritional value of edible crops. Recently, a number of research groups conducted intensive investigations on sulfur metabolism and its regulation in plants. The aim of this review is to inform the Polish reader about the new results and concepts in this field. PMID:19248587

Moniuszko, Grzegorz; Sirko, Agnieszka

2008-01-01

167

Sulfur isotopic data  

SciTech Connect

Preliminary sulfur isotope data have been determined for samples of the Vermillion Creek coal bed and associated rocks in the Vermillion Creek basin and for samples of evaporites collected from Jurassic and Triassic formations that crop out in the nearby Uinta Mountains. The data are inconclusive, but it is likely that the sulfur in the coal was derived from the evaporites.

Rye, R.O.

1987-01-01

168

Multiple sulfur isotopes and the evolution of Earth's surface sulfur cycle  

NASA Astrophysics Data System (ADS)

The distribution of sulfur isotopes in geological materials reveals information about Earth history and biogeochemical processes. Research during the last several decades has used sulfur isotope geochemistry as a tool to better understand microbial processes ( Harrison and Thode, 1958; Kaplan, 1975; Monster et al., 1979; Peck, 1959, 1962; Rees, 1973) and sediment diagenesis ( Berner, 1969, 1982; Canfield et al., 1993b). Earth historians also realized this potential, as there exists a rich record of environmental change within the sedimentary records ( Canfield and Teske, 1996; Claypool et al., 1980; Goodwin et al., 1976; Habicht et al., 2002; Kah et al., 2004; Monster et al., 1979; Shen et al., 2001; Strauss, 1993; Thode and Goodwin, 1983). These applications have championed the use of the two most abundant sulfur isotopes [ 32S and 34S], and provide a rich introduction to what the sulfur isotope record has to offer [see ( Canfield, 2004; Canfield and Raiswell, 1999)]. Within the last decade, this information has been supplemented by new data derived from the less abundant isotopes [ 33S and 36S]. The measurement of all four stable sulfur isotopes - multiple sulfur isotope geochemistry - has expanded our understanding of biological evolution and activity, atmospheric chemistry and transport, crustal recycling, and many more fields related to Earth surface processes [see ( Farquhar and Wing, 2003)]. Here, I present a review of recent works in multiple sulfur isotope geochemistry with a focus on results that inform our understanding of biogeochemical processes and Earth surface evolution.

Johnston, David T.

2011-05-01

169

Regional river sulfur runoff  

SciTech Connect

The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m/sup 2//yr. However, high sulfur runoff density in excess of 3 g S/m/sup 2//yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1--3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46--85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

Husar, R.B.; Husar, J.D.

1985-01-20

170

Exothermic Supercooled Liquid—Liquid Transition in Amorphous Sulfur  

NASA Astrophysics Data System (ADS)

Amorphous sulfur (a-S) is prepared by rapidly compressing molten sulfur to high pressure. From differential scanning calorimeter measurements, a large exothermic peak has been observed around 396 K. Online wide-angled x-ray scattering spectra indicate that no crystallization occurs in the temperature range 295-453 K, suggesting that the exothermal process corresponds to an amorphous-to-amorphous transition. The transition from amorphous sulfur to liquid sulfur is further verified by the direct observation of sulfur melt at the temperature of the associated transition. This is the first time of reporting that a-S transforms to liquid sulfur directly, which has avoided a crystallization process. What is more, the transition is an exothermic and a volume expansion process.

Zhang, Dou-Dou; Liu, Xiu-Ru; Hong, Shi-Ming; Li, Liang-Bin; Cui, Kun-Peng; Shao, Chun-Guang; He, Zhu; Xu, Ji-An

2014-06-01

171

40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2013 CFR

...remove sulfur oxides. (iii) Fossil fuel means natural gas, refinery...from such materials. (iv) Fossil fuel-fired steam generating unit...used in the process of burning fossil fuel for the purpose of producing...

2013-07-01

172

40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2010 CFR

...remove sulfur oxides. (iii) Fossil fuel means natural gas, refinery...from such materials. (iv) Fossil fuel-fired steam generating unit...used in the process of burning fossil fuel for the purpose of producing...

2010-07-01

173

40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2012 CFR

...remove sulfur oxides. (iii) Fossil fuel means natural gas, refinery...from such materials. (iv) Fossil fuel-fired steam generating unit...used in the process of burning fossil fuel for the purpose of producing...

2012-07-01

174

40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2011 CFR

...remove sulfur oxides. (iii) Fossil fuel means natural gas, refinery...from such materials. (iv) Fossil fuel-fired steam generating unit...used in the process of burning fossil fuel for the purpose of producing...

2011-07-01

175

40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2014 CFR

...remove sulfur oxides. (iii) Fossil fuel means natural gas, refinery...from such materials. (iv) Fossil fuel-fired steam generating unit...used in the process of burning fossil fuel for the purpose of producing...

2014-07-01

176

The fate of sulfur during rapid pyrolysis of scrap tires.  

PubMed

The fate of sulfur during rapid pyrolysis of scrap tires at temperatures from 673 to 1073K was investigated. Sulfur was predominant in the forms of thiophenic and inorganic sulfides in raw scrap tires. In the pyrolysis process, sulfur in organic forms was unstable and decomposed, leading to the sulfur release into tar and gases. At 673 and 773K, a considerable amount of sulfur was distributed in tar. Temperature increasing from 773 to 973K promoted tar decomposition and facilitated sulfur release into gases. At 1073K, the interactions between volatiles and char stimulated the formation of high-molecular-weight sulfur-containing compounds. After pyrolysis, almost half of the total content of sulfur in raw scrap tires still remained in the char and was mostly in the form of sulfides. Moreover, at temperatures higher than 873K, part of sulfur in the char was immobilized in the sulfates. In the pyrolysis gases, H2S was the main sulfur-containing gas. Increasing temperature stimulated the decomposition of organic polymers in scrap tires and more H2S was formed. Besides H2S, other sulfur-containing gases such as CH3SH, COS and SO2 were produced during the rapid pyrolysis of scrap tires. PMID:24238304

Hu, Hongyun; Fang, Yuan; Liu, Huan; Yu, Ren; Luo, Guangqian; Liu, Wenqiang; Li, Aijun; Yao, Hong

2014-02-01

177

High-sulfur in beef cattle diets: a review.  

PubMed

While many cattle feeding areas in the United States have long dealt with high sulfate water, increased feeding of ethanol coproducts such as distillers grains with solubles to beef cattle has led to a corresponding increase in dietary sulfur. As a result, sulfur metabolism in the ruminant has been the focus of many research studies over the past 10 yr, and advances in our knowledge have been made. Excessive sulfur in cattle diets may have implications on trace mineral absorption, dry matter intake, and overall cattle growth. This review will focus on what we have learned about the metabolism of sulfur in the ruminant, including ruminal sulfate reducing bacteria, the role of ruminally available sulfur, factors affecting the production of hydrogen sulfide in the rumen, and the potential mechanisms behind sulfur toxicity in cattle. Additionally, this review will discuss potential strategies to minimize risk of sulfur toxicity when cattle are fed high-sulfur diets, including dietary and management strategies. Further research related to high-sulfur diets including implications for carcass characteristics, meat quality, and animal health will also be discussed. As ethanol production processes continue to change, the nutrient profile of the resulting coproducts will as well. Often removal of one nutrient such as oil will result in the concentration of other nutrients such as sulfur. Therefore, it seems even more likely that a better understanding of sulfur metabolism in the ruminant will be important to beef cattle feeding in the future. PMID:24981568

Drewnoski, M E; Pogge, D J; Hansen, S L

2014-09-01

178

Sulfuric Acid on Europa  

NASA Technical Reports Server (NTRS)

Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

This image is based on data gathered by Galileo's near infrared mapping spectrometer.

Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

1999-01-01

179

Liquid and Emulsified Sulfur in Submarine Solfatara Fields of two Northern Mariana Arc Volcanoes.  

NASA Astrophysics Data System (ADS)

Because elemental sulfur melting point is ca 100 deg C (depend on allotropes and heating rate, S8 triple point temperature: 115 deg C), the evidence of liquid sulfur has been known for many subaerial crater lakes and small ponds in geothermal regions throughout the world. But the milky nature of water (sulfur-in- water emulsion in limited water mass) prohibited the direct observation of on-going processes at the bottom of these subaerial lakes. In the passive degassing environment at the summit craters of Daikoku and Nikko Seamounts of the northern Mariana Arc, the continuous flushing of sulfur emulsion by seawater allowed us to observe on- going submarine solfatara processes and associated chemistry through dives with ROVs during the NT05-18 cruise (JAMSTEC R/V Natsushima and ROV hyper-Dolphin) and the Submarine Ring of Fire 2006 cruise (R/V Melville and ROV JASON II). A higher viscosity for liquid elemental sulfur relative to that of seawater, as well as a limited stability of sulfur emulsion (aqueous sulfur sol) at high temperatures in electrolyte solution (seawater), ensures limited mobility of liquid sulfur in the conduits of hydrothermal vents. The subseafloor boiling depth of hydrothermal fluid limits the locus of any liquid sulfur reservoir. It was observed in an exposed liquid sulfur pond that the penetration of gas bubbles (mostly CO2) created sulfur emulsion while collapsing liquid sulfur film between seawater and gas bubbles. Liquid sulfur pits, encrusted sulfur, liquid sulfur fountain structure, sulfur stalactites and stalagmites, mini-pillow lava-like sulfur flows, accretionary sulfur lapilli and sulfur deltas were also observed at the summits of two volcanoes. Note: Solfatara: Italian. A type of fumarole, the gases of which are characteristically sulfurous. In 'Glossary of geology.'

Nakamura, K.; Embley, R. W.; Chadwick, W. W.; Butterfield, D. A.; Takano, B.; Resing, J. A.; de Ronde, C. E.; Lilley, M. D.; Lupton, J. E.; Merle, S. G.; Inagaki, F.

2006-12-01

180

Acid recovery from waste sulfuric acid by diffusion dialysis  

Microsoft Academic Search

In the process of sulfuric acid production from pyrite, there is a lot of waste acid produced in fume washing with dilute\\u000a acid. Acid recovery from this sort of waste sulfuric acid by diffusion dialysis is studied in the paper. The mass transfer\\u000a dialysis coefficient of sulfuric acid of the membrane AFX is measured, the effect of the flowrate of

Guiqing Zhang; Qixiu Zhang; Kanggen Zhou

1999-01-01

181

Sulfur spring dermatitis.  

PubMed

Thermal sulfur baths are a form of balneotherapy promoted in many cultures for improvement of skin conditions; however, certain uncommon skin problems may occur after bathing in hot sulfur springs. We report the case of a 65-year-old man who presented with multiple confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins after bathing in a hot sulfur spring. Histopathologic examination revealed homogeneous coagulation necrosis of the epidermis and papillary dermis. Tissue cultures showed no evidence of a microbial infection. The histopathologic findings and clinical course were consistent with a superficial second-degree burn. When patients present with these findings, sulfur spring dermatitis should be considered in the differential diagnosis. Moreover, the patient's clinical history is crucial for correct diagnosis. PMID:25474449

Lee, Chieh-Chi; Wu, Yu-Hung

2014-11-01

182

Proteomic and transcriptomic analysis of Arabidopsis seeds: molecular evidence for successive processing of seed proteins and its implication in the stress response to sulfur nutrition  

Microsoft Academic Search

Summary Seed storage proteins are synthesized as sources of carbon, nitrogen and sulfur for the next generation of plants. Their composition changes according to nutritional conditions. Here, we report the precise molecular identification of seed proteins by proteomic analysis of wild-type Arabidopsis thaliana and methionine-over- accumulating mutant mto1-1 plants. The identities of 50 protein spots were determined in the protein

Yasuhiro Higashi; Masami Yokota Hirai; Toru Fujiwara; Satoshi Naito; Masaaki Noji; Kazuki Saito

2006-01-01

183

Novel separation process of gaseous mixture of SO{sub 2} and O{sub 2} with ionic liquid for hydrogen production in thermochemical sulfur-iodine water splitting cycle  

SciTech Connect

Sulfur-Iodine cycle is the most promising thermochemical cycle for water splitting to produce hydrogen which can replace the fossil fuels in the future. As a sub-cycle in the thermochemical Sulfur-Iodine water splitting cycle, sulfuric acid (H{sub 2}SO{sub 4}) decomposes into oxygen (O{sub 2}) and sulfur dioxide (SO{sub 2}) which should be separated for the recycle of SO{sub 2} into the sulfuric acid generation reaction (Bunsen Reaction). In this study, absorption and desorption process of SO{sub 2} by ionic liquid which is useful for the recycle of SO{sub 2} into sulfuric acid generation reaction after sulfuric acid decomposition in the thermochemical Sulfur-Iodine cycle is investigated. At first, the operability as an absorbent for the SO{sub 2} absorption and desorption at high temperature without the volatilization of absorbents which is not suitable for the recycle of absorbent-free SO{sub 2} after the absorption process. The temperature range of operability is determined by TGA and DTA analysis. Most of ionic liquids investigated are applicable at high temperature desorption without volatility around 300 deg. C except [BMIm] Cl, and [BMIm] OAc which show the decomposition of ionic liquids. To evaluate the capability of SO{sub 2} absorption, each ionic liquid is located in the absorption tube and gaseous SO{sub 2} is bubbled into the ionic liquid. During the bubbling, the weight of the system is measured and converted into the absorbed SO{sub 2} amount at each temperature controlled by the heater. Saturated amounts of absorbed SO{sub 2} by ionic liquids at 50 deg. C are presented. The effect of anions for the SO{sub 2} absorption capability is shown in the order of Cl, OAc, MeSO{sub 3}, BF{sub 4}, MeSO{sub 4}, PF{sub 6}, and HSO{sub 4} when they are combined with [BMIm] cation. [BMIm]Cl has the largest amount of SO{sub 2} absorbed which can be the most promising absorbent; however, from the point of operability at high temperature which includes desorption process, [BMIm]Cl is vulnerable to high temperature around 250 deg. C based on the TGA/DTA analysis. As the second largest SO{sub 2} absorbing ionic liquid, [BMIm]OAc is not stable at the temperature around 200 deg. C either. The effect of temperature for SO{sub 2} absorption by ionic liquids at 1 atm is presented with respect to ionic liquids. The amount of absorbed SO{sub 2} decreases as temperature increases for all ionic liquids experimented. At low temperature the difference of the absorbed SO{sub 2} between each ionic liquid is bigger than that of at high temperature. The effect of partial pressure of SO{sub 2} to the absorbed SO{sub 2} amount is presented. The partial pressure of SO{sub 2} is controlled by changing the ratio between inert He and SO{sub 2}. The amount of absorbed SO{sub 2} increases as partial pressure of SO{sub 2} increases for [DMIm] MeSO{sub 4}. The trends of SO{sub 2} absorption depending on the temperature which is mentioned earlier are also recognized. Until now, the solubility of SO{sub 2} in the ionic liquids is investigated. However, in the sulfur cycle, oxygen exists together with SO{sub 2} as the products of sulfuric acid decomposition after H{sub 2}O removal by condensation. The solubility of oxygen in the ionic liquid, which can be expected as negligible because of its non-polarity of the molecule, is measured with the same apparatus by changing the feeding gas into oxygen. Solubility of oxygen and SO{sub 2} is compared where [EMIm] EtSO{sub 4} is used as an absorbent at 1 atm 50 deg. C. The amount of absorbed oxygen is much less than that of SO{sub 2} by the order difference. The absorption mechanism of SO{sub 2} in the ILs is known as physical absorption by many researchers these days, where chemical absorption is also reported with some ionic liquids. Physical absorption property of ionic liquids is necessary for the recycle process of the absorbed pure SO{sub 2} into sulfuric acid generation reaction. By the FT-IR spectra, the physical absorption is verified with the fact that no spectra peak position change of ionic liquids

Kim, Chang Soo; Gong, Gyeong Taek; Yoo, Kye Sang; Kim, Honggon; Lee, Byoung Gwon; Ahn, Byoung Sung; Jung, Kwang Deog [Clena Energy Research Center, Energy and Environment Technology Division, Korea Institute of Science and Technology, Hawolgokdong 39-1, Seongbukgu, Seoul 139-791 (Korea, Republic of); Lee, Ki Yong; Song, Kwang Ho [Department of Chemical and Biological Engineering, Korea University, Anamdong, Seongbukgu, Seoul 136-701 (Korea, Republic of)

2007-07-01

184

Mass-dependent sulfur isotope fractionation during reoxidative sulfur cycling: A case study from Mangrove Lake, Bermuda  

NASA Astrophysics Data System (ADS)

The multiple sulfur isotope composition of porewater sulfate from the anoxic marine sapropel of Mangrove Lake, Bermuda was measured in order to establish how multiple sulfur isotopes are fractionated during reoxidative sulfur cycling. The porewater-sulfate ?34S and ?33S dataset exhibits the distinct isotopic signatures of microbial sulfate reduction and sulfur reoxidation. We reproduced the measurements with a simple diagenetic model that yielded fractionation factors for net sulfate removal of between -29.2‰ and -32.5‰. A new approach to isotopic modeling of the sulfate profiles, informed by the chemistry of sulfur intermediate compounds in Mangrove Lake, reveals that sulfate reduction produces a relatively small intrinsic fractionation and that an active reoxidative sulfur cycle increases the fractionation of the measured values. Based on the model results, the reoxidative cycle of Mangrove Lake appears to include sulfide oxidation to elemental sulfur followed by the disproportionation of the elemental sulfur to sulfate and sulfide. This model also indicates that the reoxidative sulfur cycle of Mangrove Lake turns over from 50 to 80% of the sulfide produced by microbial sulfate reduction. The Mangrove Lake case study shows how sulfur isotope fractionations can be separated into three different “domains” in ?33S-?34S space based on their ability to resolve reductive and reoxidative sulfur transformations. The first domain that differentiates reductive and reoxidative sulfur cycling is well illustrated by previous studies and requires 34S-32S fractionations more negative than ?-70‰, beyond the fractionation limit of microbial sulfate reduction at earth surface temperatures. The second domain that distinguishes reductive and reoxidative processes is between 34S-32S fractionations of -40‰ and 0‰, where the 33S-32S fractionations of sulfate reduction and reoxidation are significantly different. In the remaining domain (between 34S-32S fractionations -70‰ and -40‰), the similarity of the multiple sulfur isotope signals from microbial sulfate reduction and disproportionation means that the two processes cannot be discriminated from each other.

Pellerin, André; Bui, Thi Hao; Rough, Mikaella; Mucci, Alfonso; Canfield, Donald E.; Wing, Boswell A.

2015-01-01

185

Optimization studies in sulfuric acid production  

Microsoft Academic Search

Current legislation imposes tighter restrictions to reduce the impact of process industry on environment. This work presents the dynamic simulation and optimization results for an existing sulfuric acid plant. Operational problems may occur when the process is disturbed due to production rate changes or catalyst deactivation, the non-linear response of the plant leading to sustained oscillations. Since the plant is

Anton A. Kiss; Costin S. Bildea; Peter J. T. Verheijen

2006-01-01

186

Sulfur Limits of Detection and Spectral Interference Corrections for DWPF Sludge Matrices by Inductively Coupled Plasma Emission Spectrometry  

Microsoft Academic Search

The Savannah River Technology Center (SRTC) has been requested to perform sulfur (S) analysis on digested radioactive sludge and supernatant samples by Inductively Coupled Plasma Emission Spectrometry (ICP-ES). The amount of sulfur is a concern because there are sulfur limits for the incoming feed, due to glass melter, process vessel, and off-gas line corrosion concerns and limited sulfur solubility in

2004-01-01

187

Multiple sulfur isotopes fractionations associated with abiotic sulfur transformations in Yellowstone National Park geothermal springs  

PubMed Central

Background The paper presents a quantification of main (hydrogen sulfide and sulfate), as well as of intermediate sulfur species (zero-valent sulfur (ZVS), thiosulfate, sulfite, thiocyanate) in the Yellowstone National Park (YNP) hydrothermal springs and pools. We combined these measurements with the measurements of quadruple sulfur isotope composition of sulfate, hydrogen sulfide and zero-valent sulfur. The main goal of this research is to understand multiple sulfur isotope fractionation in the system, which is dominated by complex, mostly abiotic, sulfur cycling. Results Water samples from six springs and pools in the Yellowstone National Park were characterized by pH, chloride to sulfate ratios, sulfide and intermediate sulfur species concentrations. Concentrations of sulfate in pools indicate either oxidation of sulfide by mixing of deep parent water with shallow oxic water, or surface oxidation of sulfide with atmospheric oxygen. Thiosulfate concentrations are low (<6 ?mol L-1) in the pools with low pH due to fast disproportionation of thiosulfate. In the pools with higher pH, the concentration of thiosulfate varies, depending on different geochemical pathways of thiosulfate formation. The ?34S values of sulfate in four systems were close to those calculated using a mixing line of the model based on dilution and boiling of a deep hot parent water body. In two pools ?34S values of sulfate varied significantly from the values calculated from this model. Sulfur isotope fractionation between ZVS and hydrogen sulfide was close to zero at pH?sulfur is slightly heavier than hydrogen sulfide due to equilibration in the rhombic sulfur–polysulfide – hydrogen sulfide system. Triple sulfur isotope (32S, 33S, 34S) fractionation patterns in waters of hydrothermal pools are more consistent with redox processes involving intermediate sulfur species than with bacterial sulfate reduction. Small but resolved differences in ?33S among species and between pools are observed. Conclusions The variation of sulfate isotopic composition, the origin of differences in isotopic composition of sulfide and zero–valent sulfur, as well as differences in ?33S of sulfide and sulfate are likely due to a complex network of abiotic redox reactions, including disproportionation pathways. PMID:24959098

2014-01-01

188

Biotic and abiotic carbon to sulfur bond cleavage  

SciTech Connect

Cleavage of aliphatic organosulfonate carbon to sulfur (C-S) bonds, a critical link in the global biogeochemical sulfur cycle, has been identified in Escherichia coli K-12. Enormous quantities of inorganic sulfate are continuously converted (Scheme I) into methanesulfonic acid 1 and acylated 3-(6-sulfo-{alpha}-D-quinovopyranosyl)-L-glycerol 2. Biocatalytic desulfurization (Scheme I) of 1 and 2, which share the structural feature of an aliphatic carbon bonded to a sulfonic acid sulfur, completes the cycle, Discovery of this desulfurization in E. coli provides an invaluable paradigm for study of a biotic process which, via the biogeochemical cycle, significantly influences the atmospheric concentration of sulfur-containing molecules.

Frost, J.W.

1991-01-01

189

PROCESS ENGINEERING STUDIES OF THE PERCHLOROETHYLENE COAL CLEANING PROCESS  

Microsoft Academic Search

The perchloroethylene coal cleaning process has proven to be very effective in removing both organic and pyritic sulfur from high-sulfur coals. The process removes 30%- 70% of the organic sulfur and 90%- 99% of the pyritic sulfur with very little loss (<1.0 wt%) of hydrocarbons and their heating value. The process has been investigated on a bench- scale and a

Kathy L. Fullerton; Sunggyu Lee; Conrad J. Kulik

1991-01-01

190

THE ANTIBACTERIAL PROPERTIES OF SULFUR  

PubMed Central

1. Saturated solutions of sulfur in alcohol (alcohol-sulfur) when diluted with broth are inhibitory to the growth of various Gram-positive bacteria and to C. hominis. By an arbitrary method of unitage with S. aureus as the test organism, our alcohol-sulfur contains 1,600 to 2,000 units per cc. and one unit contains between 0.24 and 0.34 gamma sulfur. The activity of a preparation is in general directly proportional to its sulfur content. 2. Solutions of sulfur in carbowax (carbowax-sulfur) when diluted with broth are likewise inhibitory to the growth of various Gram-positive bacteria and to C. hominis. When S. aureus is used as test organism, 1 unit contains between 0.1 and 0.2 gamma sulfur. The activity of these preparations is also in general directly proportional to their sulfur content. 3. Carbowax-sulfur when incorporated in agar in 1–500 to 1–2,000 dilution inhibits the growth of various Gram-positive aerobic and anaerobic bacteria, C. hominis, and certain dermatophytes. 4. Our experiments appear to show that both alcohol-sulfur and carbowax-sulfur owe their inhibitory properties to the sulfur particles that are dispersed throughout the medium when these sulfur preparations are diluted with broth. The inhibitory effect of these particles may or may not be due to a combination of the sulfur particles with substances in the medium in which they are suspended. 5. Evidence suggests that the activity of both alcohol-sulfur and carbowax-sulfur is due to sulfur in the same form. The inhibitory effect is characterized by prolonged bacteriostasis with similar activity over a wide range of dilutions. There is no evidence of true bactericidal action even with the highest concentrations used. PMID:19871634

Weld, Julia T.; Gunther, Anne

1947-01-01

191

Comparative Aspects of Sulfur Mineralization in Sediments of a Eutrophic Lake Basin †  

PubMed Central

The net mineralization of organic sulfur compounds in surface sediments of Wintergreen Lake was estimated from a mass-balance budget of sulfur inputs and sediment sulfur concentrations. The net mineralization of organic sulfur inputs is <50% complete, which is consistent with the dominance of organic sulfur (>80% of total sulfur) in sediment. Although sediment sulfur is predominantly organic, sulfate reduction is the most significant process in terms of the quantities of sulfur transformed in surface sediments. Rates of sulfate reduction in these sediments average 7 mmol/m2 per day. On an annual basis, this rate is 19-fold greater than net rates of organic sulfur mineralization and 65-fold greater than sulfate ester hydrolysis. PMID:16346037

King, Gary M.; Klug, M. J.

1982-01-01

192

Sulfur Substitution in Oxyanions.  

NASA Astrophysics Data System (ADS)

Sulfide can react with oxyanions in two ways. In anions such as chromate, iodate or permanganate, the central metal(loid) is reduced rapidly. In anions such as molybdate, arsenate or antimonate, sulfur atoms substitute for oxygen atoms in the first coordination sphere. In the latter cases, the central metal(loid) often retains its high oxidation state in the final thioanion; however lower valent species, which tend to be coordinatively more labile, may be important reaction intermediates. Replacement of oxygen by sulfur "softens" oxyanions, in some cases making them strong binders of soft metals, like Cu, Ag, Au and Hg. These changes also can profoundly affect the geochemical fate of the metal(loids). Sulfur substitution in oxyanions can be extremely sluggish. Recently, computational chemistry has begun to yield information about sulfur substitution reactions that are too slow to be studied experimentally but yet are potentially important in geochemistry. Thioperrhenates, thiovanadates and thiotungstates are species whose geochemical roles, if any, remain to be determined. It is possible that sulfur substitution reactions are more important under hydrothermal conditions than at ambient temperatures. For example, germanate dominates the ambient-temperature chemistry of Ge, but in hydrothermal deposits this element occurs commonly in sulfide minerals.

Helz, G. R.

2008-12-01

193

Oxidation of nauseous sulfur compounds by photocatalysis or photosensitization  

Microsoft Academic Search

Reduced sulfur compounds such as methanethiol (MSH), dimethylsulfide (DMS) and dimethydisulfide (DMDS) are nauseous by-products produced by a great number of industrial processes. Oxidation of these reduced sulfur compounds in polluted atmospheres and hence the decrease of their harmful and malodorous effects is thus a matter of concern in numerous industrial and water treatment plants. Photocatalytic treatment of gaseous flow

C. Cantau; S. Larribau; T. Pigot; M. Simon; M. T. Maurette; S. Lacombe

2007-01-01

194

Sulfur copolymers for infrared optical imaging  

NASA Astrophysics Data System (ADS)

The development of organic polymers with low infrared absorption has been investigated as a possible alternative to inorganic metal oxide, semiconductor, or chalcogenide-based materials for a variety of optical devices and components, such as lenses, goggles, thermal imaging cameras and optical fibers. In principle, organic-based polymers are attractive for these applications because of their low weight, ease of processing, mechanical toughness, and facile chemical variation using commercially available precursors. Herein we report on the optical characterization of a new class of sulfur copolymers that are readily moldable, transparent above 500 nm, possess high refractive index (n > 1.8) and take advantage of the low infrared absorption of S-S bonds for potential use in the mid-infrared at 3-5 microns. These materials are largely made from elemental sulfur by an inverse vulcanization process; in the current study we focus on the properties of a chemically stable, branched copolymer of poly(sulfur-random-1,3-diisopropenylbenzene) (poly(S-r- DIB). Copolymers with elemental sulfur content ranging from 50% to 80% by weight were studied by UV-VIS spectroscopy, FTIR, and prism coupling for refractive index measurement. Clear correlation between material composition and the optical properties was established, confirming that the high polarizability of the sulfur atom leads to high refractive index while also maintaining low optical loss in the infrared.

Namnabat, S.; Gabriel, J. J.; Pyun, J.; Norwood, R. A.; Dereniak, E. L.; van der Laan, J.

2014-06-01

195

Natural sulfur dioxide emissions from sulfuric soils  

NASA Astrophysics Data System (ADS)

Soils have long been recognised as sulfur dioxide (SO 2) sinks, but we show that they can also be sources of atmospheric SO 2. Using static chambers and micrometeorological techniques, we have measured emissions of SO 2 from coastal lowland soils containing sulfides (mostly pyrite), commonly referred to as acid sulfate soils in Australia. SO 2 evolution seems coupled to evaporation of soil water containing sulfite. The global emissions of S from acid sulfate soils is estimated at about 3 Tg/year, which is of the same order as emissions from terrestrial biogenic sources and biomass burning and is about 3% of known anthropogenic emissions of S.

Macdonald, Bennett C. T.; Denmead, O. Tom; White, Ian; Melville, Michael D.

196

Analytical method for the evaluation of sulfur functionalities in American coals. Final report  

SciTech Connect

This investigation consisted of the following 6 tasks: (1) improve the instrumentation for the sulfur functional groups analysis and make it more reliable. (2) create a set of reference standards of sulfur-containing compounds. (3) examine the sulfur groups distribution in untreated and desulfurized coals. (4) examine the sulfur functionalities in raw and processed coals, i.e., liquefied coals. (5) determine the distribution of sulfur functionalities in modified coals. (6) prepare computer programs for calculations related to the distribution of sulfur functional groups in coal. Each task is discussed and results are presented. Appendix A contains the computer program used to interpret the data. 31 references, 56 figures, 17 tables.

Attar, A.

1983-05-01

197

Phase transformations and the spectral reflectance of solid sulfur - Can metastable sulfur allotropes exist on Io?  

NASA Technical Reports Server (NTRS)

Laboratory investigations have been conducted on the effects of variations in sulfur sample histories on their solid-state transformation rate and the corresponding spectral variation of freshly frozen sulfur. The temporal variations in question may be due to differences in the amount and type of metastable allotropes present in the sulfur after solidification, as well as to the physics of the phase-transformation process itself. The results obtained are pertinent to the physical behavior and spectral variation of such freshly solidified sulfur as may exist on the Jupiter moon Io; this would initially solidify into a glassy solid or monoclinic crystalline lattice, then approach ambient dayside temperatures. Laboratory results imply that the monoclinic or polymeric allotropes can in these circumstances be maintained, and will take years to convert to the stable orthorhombic crystalline form.

Moses, Julianne I.; Nash, Douglas B.

1991-01-01

198

Phase transformations and the spectral reflectance of solid sulfur - Can metastable sulfur allotropes exist on Io?  

NASA Astrophysics Data System (ADS)

Laboratory investigations have been conducted on the effects of variations in sulfur sample histories on their solid-state transformation rate and the corresponding spectral variation of freshly frozen sulfur. The temporal variations in question may be due to differences in the amount and type of metastable allotropes present in the sulfur after solidification, as well as to the physics of the phase-transformation process itself. The results obtained are pertinent to the physical behavior and spectral variation of such freshly solidified sulfur as may exist on the Jupiter moon Io; this would initially solidify into a glassy solid or monoclinic crystalline lattice, then approach ambient dayside temperatures. Laboratory results imply that the monoclinic or polymeric allotropes can in these circumstances be maintained, and will take years to convert to the stable orthorhombic crystalline form.

Moses, J. I.; Nash, D. B.

1991-02-01

199

Sodium sulfur battery seal  

SciTech Connect

This disclosure is directed to an improvement in a sodium sulfur battery construction in which a seal between various battery compartments is made by a structure in which a soft metal seal member is held in a sealing position by holding structure. A pressure applying structure is used to apply pressure on the soft metal seal member when it is being held in sealing relationship to a surface of a container member of the sodium sulfur battery by the holding structure. The improvement comprises including a thin, well-adhered, soft metal layer on the surface of the container member of the sodium sulfur battery to which the soft metal seal member is to be bonded.

Mikkor, Mati (Ann Arbor, MI)

1981-01-01

200

Interstellar sulfur chemistry  

NASA Technical Reports Server (NTRS)

The results of a chemical model of SO, CS, and OCS chemistry in dense clouds are summarized. The results are obtained from a theoretical study of sulfur chemistry in dense interstellar clouds using a large-scale time-dependent model of gas-phase chemistry. Among the results are the following: (1) owing to activation energy, the reaction of CS with O atoms is efficient as a loss mechanism of CS during the early phases of cloud evolution or in hot and oxygen-rich sources such as the KL nebula; (2) if sulfur is not abnormally depleted in dense clouds, then the observed abundances of SO, SO2, H2S, CS, OCS, H2CS, and SiS indicate that sulfur is mostly atomic in dense clouds; and (3) OCS is stable against reactions with neutral atoms and radicals in dense clouds.

Prasad, S. S.; Huntress, W. T., Jr.

1980-01-01

201

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2012 CFR

...ambient air quality standard for sulfur oxides (sulfur dioxide). 50.5 Section...ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The...shall be rounded up). (b) Sulfur oxides shall be measured in the ambient...

2012-07-01

202

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2013 CFR

...ambient air quality standard for sulfur oxides (sulfur dioxide). 50.5 Section...ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The...shall be rounded up). (b) Sulfur oxides shall be measured in the ambient...

2013-07-01

203

Sulfurization induced surface constitution and its correlation to the performance of solution-processed Cu2ZnSn(S,Se)4 solar cells.  

PubMed

To obtain high photovoltaic performances for the emerging copper zinc tin sulfide/selenide (CZTSSe) thin film solar cells, much effort has deservedly been placed on CZTSSe phase purification and CZTSSe grain size enhancement. Another highly crucial but less explored factor for device performance is the elemental constitution of CZTSSe surface, which is at the heart of p-n junction where major photogenerated carriers generate and separate. In this work we demonstrate that, despite the well-built phase and large grained films are observed by common phases and morphology characterization (XRD, Raman and SEM), prominent device efficiency variations from short circuited to 6.4% are obtained. Insight study highlights that the surface (0-250 nm) compositions variation results in different bulk defect depths and doping densities in the depletion zone. We propose that suitable sulfurization (at ~ 10 kPa sulfur pressure) drives optimization of surface constitution by managing the Cu, Zn and Sn diffusion and surface reaction. Therefore, our study reveals that the balance of elemental diffusion and interface reactions is the key to tuning the surface quality CZTSSe film and thus the performance of as resulted devices. PMID:25190491

Zhong, Jie; Xia, Zhe; Luo, Miao; Zhao, Juan; Chen, Jie; Wang, Liang; Liu, Xinsheng; Xue, Ding-Jiang; Cheng, Yi-Bing; Song, Haisheng; Tang, Jiang

2014-01-01

204

Sulfurization induced surface constitution and its correlation to the performance of solution-processed Cu2ZnSn(S,Se)4 solar cells  

PubMed Central

To obtain high photovoltaic performances for the emerging copper zinc tin sulfide/selenide (CZTSSe) thin film solar cells, much effort has deservedly been placed on CZTSSe phase purification and CZTSSe grain size enhancement. Another highly crucial but less explored factor for device performance is the elemental constitution of CZTSSe surface, which is at the heart of p-n junction where major photogenerated carriers generate and separate. In this work we demonstrate that, despite the well-built phase and large grained films are observed by common phases and morphology characterization (XRD, Raman and SEM), prominent device efficiency variations from short circuited to 6.4% are obtained. Insight study highlights that the surface (0–250?nm) compositions variation results in different bulk defect depths and doping densities in the depletion zone. We propose that suitable sulfurization (at ~10?kPa sulfur pressure) drives optimization of surface constitution by managing the Cu, Zn and Sn diffusion and surface reaction. Therefore, our study reveals that the balance of elemental diffusion and interface reactions is the key to tuning the surface quality CZTSSe film and thus the performance of as resulted devices. PMID:25190491

Zhong, Jie; Xia, Zhe; Luo, Miao; Zhao, Juan; Chen, Jie; Wang, Liang; Liu, Xinsheng; Xue, Ding-Jiang; Cheng, Yi-Bing; Song, Haisheng; Tang, Jiang

2014-01-01

205

Thiosulfate and Sulfur Oxidation in Purple Sulfur Bacteria  

Microsoft Academic Search

In chemotrophic and phototrophic sulfur oxidizers that do not form sulfur deposits a periplasmic thiosulfate-oxidizing multienzyme\\u000a complex (Sox complex) has been described to be responsible for formation of sulfate from thiosulfate. In the anoxygenic phototrophic\\u000a sulfur bacterium Allochromatium vinosum intracellular sulfur globules are an obligate intermediate during the oxidation of thiosulfate to sulfate. Despite this fundamental\\u000a difference A. vinosum possesses

Frauke Grimm; Bettina Franz; Christiane Dahl

206

The role of cluster energy nonaccommodation in atmospheric sulfuric acid Theo Kurtn,1,a  

E-print Network

The role of cluster energy nonaccommodation in atmospheric sulfuric acid nucleation Theo Kurtén,1,a formation due to liberated excess energy in atmospheric nucleation processes involving sulfuric acid for small sulfuric acid-- containing clusters. We find that energy nonaccommodation effects may, at most

207

ON-LINE OPTIMIZATION, ENERGY ANALYSIS AND ENVIRONMENTAL IMPACT ASSESSMENT OF SULFURIC ACID CATALYZED ALKYLATION  

E-print Network

ON-LINE OPTIMIZATION, ENERGY ANALYSIS AND ENVIRONMENTAL IMPACT ASSESSMENT OF SULFURIC ACID in sulfuric acid consumption potentially could be obtained. 1. Introduction Alkylation process is one and procedures (Albright 1990, Cupit et al. 1961). In this study a commercial sulfuric acid catalyzed alkylation

Pike, Ralph W.

208

Vapor phase elemental sulfur amendment for sequestering mercury in contaminated soil  

DOEpatents

The process of treating elemental mercury within the soil is provided by introducing into the soil a heated vapor phase of elemental sulfur. As the vapor phase of elemental sulfur cools, sulfur is precipitated within the soil and then reacts with any elemental mercury thereby producing a reaction product that is less hazardous than elemental mercury.

Looney, Brian B.; Denham, Miles E.; Jackson, Dennis G.

2014-07-08

209

Sulfuric acid in the Venus clouds.  

NASA Technical Reports Server (NTRS)

The extremely dry nature of the Venus upper atmosphere appears to demand the presence of an efficient desiccating agent as the chief constituent of the clouds of Venus. On the basis of polarization measures it is to be expected that this substance is present as spherical droplets, 1 to 2 microns in diameter, with a refractive index n of 1.46 plus or minus 0.02 at 3500A in the observed region of the atmosphere, with T about equal to 235 K. This substance must have ultraviolet, visible, and infrared reflection properties not inconsistent with the observed spectrum of Venus. Sulfuric acid, of about 86% by weight composition, roughly fulfills the first of these properties. The visible and ultraviolet transmission features of a thin layer of elemental bromine and hydrobromic acid dissolved in sulfuric acid somewhat resemble the Venus spectrum, up to 14 microns. The chemical process postulated for forming sulfuric acid involves the oxidation of sulfur and its compounds to sulfuric acid through the agency of elemental bromine produced by the photolytic decomposition of hydrogen bromide.

Sill, G. T.

1972-01-01

210

Sulfur 'Concrete' for Lunar Applications - Environmental Considerations  

NASA Technical Reports Server (NTRS)

Commercial use of sulfur concrete on Earth is well established, particularly in corrosive, e.g., acid and salt, environments. Having found troilite (FeS) on the Moon raises the question of using extracted sulfur as a lunar construction material, an attractive alternative to conventional concrete as it does not require water. For the purpose of this Technical Memorandum, it is assumed that lunar ore is mined, refined, and the raw sulfur processed with appropriate lunar regolith to form, for example, bricks. With this stipulation, it is then noted that the viability of sulfur concrete in a lunar environment, which is characterized by lack of an atmosphere and extreme temperatures, is not well understood. The work presented here evaluates two sets of small sulfur concrete samples that have been prepared using JSC-1 lunar simulant as an aggregate addition. One set was subjected to extended periods in high vacuum to evaluate sublimation issues, and the other was cycled between room and liquid nitrogen temperatures to investigate their subsequent mechanical integrity. Results are presented from both investigations, discussed, and put into the context of the lunar environment.

Grugel, R. N.

2008-01-01

211

CONTROLLING SULFUR OXIDES  

EPA Science Inventory

This Research Summary describes EPA's program to develop new and improve existing technologies for sulfur oxides control. As we increasingly turn to coal as the primary utility and industrial fuel, while trying to deal with the problems of acid precipitation, visibility degradati...

212

Sulfur in basaltic magmas  

Microsoft Academic Search

The concentration of S in basaltic magmas at 1 atm pressure is strongly dependent on temperature, the fugacities of oxygen ( f O 2 ) and sulfur ( f S 2 ), and bulk composition. Microprobe analyses of total S in rapidly quenched, submarine basalt glasses, used in conjunction with wet chemical analyses of Fe 2 O 3 \\/ FeO

Paul Wallace; Ian S. E. Carmichael

1992-01-01

213

Sodium sulfur battery seal  

Microsoft Academic Search

This disclosure is directed to an improvement in a sodium sulfur battery construction in which a seal between various battery compartments is made by a structure in which a soft metal seal member is held in a sealing position by holding structure. A pressure applying structure is used to apply pressure on the soft metal seal member when it is

Mikkor; Mati

1981-01-01

214

Sodium sulfur battery seal  

DOEpatents

This invention is directed to a seal for a sodium sulfur battery in which a flexible diaphragm sealing elements respectively engage opposite sides of a ceramic component of the battery which separates an anode compartment from a cathode compartment of the battery.

Topouzian, Armenag (Birmingham, MI)

1980-01-01

215

Sodium sulfur battery seal  

Microsoft Academic Search

This invention is directed to a seal for a sodium sulfur battery in which a flexible diaphragm sealing elements respectively engage opposite sides of a ceramic component of the battery which separates an anode compartment from a cathode compartment of the battery. 3 figs.

Topouzian

1980-01-01

216

COAL SULFUR MEASUREMENTS  

EPA Science Inventory

The report describes a new technique for sulfur forms analysis based on low-temperature oxygen plasma ashing. The technique involves analyzing the low-temperature plasma ash by modified ASTM techniques after selectively removing the organic material. The procedure has been tested...

217

Thermophilic Carbon-Sulfur-Bond-Targeted Biodesulfurization  

PubMed Central

Petroleum contains many heterocyclic organosulfur compounds refractory to conventional hydrodesulfurization carried out with chemical catalysts. Among these, dibenzothiophene (DBT) and DBTs bearing alkyl substitutions are representative compounds. Two bacterial strains, which have been identified as Paenibacillus strains and which are capable of efficiently cleaving carbon-sulfur (C--S) bonds in DBT at high temperatures, have been isolated for the first time. Upon attacking DBT and its various methylated derivatives at temperatures up to 60(deg)C, both growing and resting cells of these bacteria can release sulfur atoms as sulfate ions and leave the monohydroxylated hydrocarbon moieties intact. Moreover, when either of these paenibacilli was incubated at 50(deg)C with light gas oil previously processed through hydrodesulfurization, the total sulfur content in the oil phase clearly decreased. PMID:16535672

Konishi, J.; Ishii, Y.; Onaka, T.; Okumura, K.; Suzuki, M.

1997-01-01

218

An Aerosol Condensation Model for Sulfur Trioxide  

SciTech Connect

This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992, world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to as oleum) is [7], the volatile product being sulfur trioxide. Sulfate aerosols and mist may form in the atmosphere on tank rupture. From chemical spill data from 1990-1996, Lawuyi02 and Fingas [7] prioritize sulfuric acid as sixth most serious. During this period, they note 155 spills totaling 13 Mt, out of a supply volume of 3700 Mt. Lawuyi and Fingas [7] summarize information on three major sulfuric acid spills. On 12 February 1984, 93 tons of sulfuric acid were spilled when 14 railroad cars derailed near MacTier, Parry Sound, Ontario. On 13 December 1978, 51 railroad cars derailed near Springhill, Nova Scotia. One car, containing 93% sulfuric acid, ruptured, spilling nearly its entire contents. In July 1993, 20 to 50 tons of fuming sulfuric acid spilled at the General Chemical Corp. plant in Richmond, California, a major industrial center near San Francisco. The release occurred when oleum was being loaded into a nonfuming acid railroad tank car that contained only a rupture disk as a safety device. The tank car was overheated and this rupture disk blew. The resulting cloud of sulfuric acid drifted northeast with prevailing winds over a number of populated areas. More than 3,000 people subsequently sought medical attention for burning eyes, coughing, headaches, and nausea. Almost all were treated and released on the day of the spill. By the day after the release, another 5,000 people had sought medical attention. The spill forced the closure of five freeways in the region as well as some Bay Area Rapid Transit System stations. Apart from corrosive toxicity, there is the additional hazard that the reactions of sulfur trioxide and sulfuric acid vapors with water are extremely exothermic [10, 11]. While the vapors are intrinsically denser than air, there is thus the likelihood of strong, warming-induced buoyancy from reactions with ambient water vapor, water-containing aerosol droplets, and wet environmental surface. Nordin [12] relates just such an occurrence following the Richmond, CA spill, with the plume observed to rise to 300 m. For all practical purposes, sulfur trioxide was the constituent released from the heated tank

Grant, K E

2008-02-07

219

The use of elemental sulfur as an alternative feedstock for polymeric materials  

NASA Astrophysics Data System (ADS)

An excess of elemental sulfur is generated annually from hydrodesulfurization in petroleum refining processes; however, it has a limited number of uses, of which one example is the production of sulfuric acid. Despite this excess, the development of synthetic and processing methods to convert elemental sulfur into useful chemical substances has not been investigated widely. Here we report a facile method (termed ‘inverse vulcanization’) to prepare chemically stable and processable polymeric materials through the direct copolymerization of elemental sulfur with vinylic monomers. This methodology enabled the modification of sulfur into processable copolymer forms with tunable thermomechanical properties, which leads to well-defined sulfur-rich micropatterned films created by imprint lithography. We also demonstrate that these copolymers exhibit comparable electrochemical properties to elemental sulfur and could serve as the active material in Li-S batteries, exhibiting high specific capacity (823 mA h g-1 at 100 cycles) and enhanced capacity retention.

Chung, Woo Jin; Griebel, Jared J.; Kim, Eui Tae; Yoon, Hyunsik; Simmonds, Adam G.; Ji, Hyun Jun; Dirlam, Philip T.; Glass, Richard S.; Wie, Jeong Jae; Nguyen, Ngoc A.; Guralnick, Brett W.; Park, Jungjin; Somogyi, Árpád; Theato, Patrick; Mackay, Michael E.; Sung, Yung-Eun; Char, Kookheon; Pyun, Jeffrey

2013-06-01

220

Consistency Between Measurements and Theory for Sulfur Gases and Oxidants During the Pacific Atmospheric Sulfur Experiment  

NASA Astrophysics Data System (ADS)

Airborne gas phase measurements of sulfur dioxide, dimethylsulfide, dimethylsulfoxide, methane sulfonic acid, sulfuric acid, hydroxyl, perhydroxyl, hydrogen peroxide, methylhydroperoxide, ozone, and carbon monoxide together with aerosol microphysical properties and bulk and size-dependent aerosol composition are examined for consistency with photochemical theory. The observations come from 14 research flights using the NCAR C-130 flown mostly southeast of Kiritimati in relatively cloud-free marine boundary layer air. This region was chosen because of its extremely low nitrogen oxide mixing ratios and minimal horizontal gradients in composition. A size-dependent gas-particle mass-transfer model is used to calculate the exchange rates of dimethylsulfoxide, methanesulfonic acid and sulfuric acid between the gas and aerosol. Gas kinetic reactions, aqueous reactions, and heterogeneous processes are used in the evaluation. Mass accommodation coefficients, Henry's Law solubilities, and the effective yields of methanesulfonic acid, sulfur dioxide, sulfuric acid and dimethylsulfoxide from dimethylsulfide are estimated and consistent with the literature. Gas phase hydroxyl chemistry alone is sufficient to explain observed methanesulfonic acid and sulfuric acid vapor concentrations.

Heikes, B. G.; Higbie, A.; O'Sullivan, D. W.; Bandy, A. R.; Mauldin, L.; Cantrell, C.; Anderson, R. S.; Campos, T.; Huebert, B.; Bloomquist, B.; Wang, Y.; Heizer, C. G.; Pollack, I. B.; Weinheimer, A. J.

2008-12-01

221

Sulfur-impregnated core-shell hierarchical porous carbon for lithium-sulfur batteries.  

PubMed

Core-shell hierarchical porous carbon spheres (HPCs) were synthesized by a facile hydrothermal method and used as host to incorporate sulfur. The microstructure, morphology, and specific surface areas of the resultant samples have been systematically characterized. The results indicate that most of sulfur is well dispersed over the core area of HPCs after the impregnation of sulfur. Meanwhile, the shell of HPCs with void pores is serving as a retard against the dissolution of lithium polysulfides. This structure can enhance the transport of electron and lithium ions as well as alleviate the stress caused by volume change during the charge-discharge process. The as-prepared HPC-sulfur (HPC-S) composite with 65.3?wt?% sulfur delivers a high specific capacity of 1397.9?mA?h?g(-1) at a current density of 335?mA?g(-1) (0.2 C) as a cathode material for lithium-sulfur (Li-S) batteries, and the discharge capacity of the electrode could still reach 753.2?mA?h?g(-1) at 6700?mA?g(-1) (4?C). Moreover, the composite electrode exhibited an excellent cycling capacity of 830.5?mA?h?g(-1) after 200?cycles. PMID:25346404

Zhang, Fei-Fei; Huang, Gang; Wang, Xu-Xu; Qin, Yu-Ling; Du, Xin-Chuan; Yin, Dong-Ming; Liang, Fei; Wang, Li-Min

2014-12-22

222

40 CFR 60.104 - Standards for sulfur oxides.  

Code of Federal Regulations, 2013 CFR

...the following conditions for each affected fluid catalytic cracking unit catalyst regenerator: (1) With an add-on control...coke burn-off; or (3) Process in the fluid catalytic cracking unit fresh feed that has a total sulfur...

2013-07-01

223

40 CFR 60.104 - Standards for sulfur oxides.  

Code of Federal Regulations, 2014 CFR

...the following conditions for each affected fluid catalytic cracking unit catalyst regenerator: (1) With an add-on control...coke burn-off; or (3) Process in the fluid catalytic cracking unit fresh feed that has a total sulfur...

2014-07-01

224

40 CFR 60.104 - Standards for sulfur oxides.  

Code of Federal Regulations, 2011 CFR

...the following conditions for each affected fluid catalytic cracking unit catalyst regenerator: (1) With an add-on control...coke burn-off; or (3) Process in the fluid catalytic cracking unit fresh feed that has a total sulfur...

2011-07-01

225

Removal of sulfur dioxide from waste gases. [Tertiary amines  

SciTech Connect

In this efficient, low-cost sulfur dioxide-removal process, a waste-gas stream (such as stack gases) contacts free selective tertiary amines having basic strengths greater than about pK 5 (such as trimethylamine, triethylamine, and tri-n-butylamine) to form a coordinate covalent complex of the amine and the sulfur dioxide. The thermal regeneration of this sufficiently stable complex then liberates a stream of sulfur dioxide and a stream of residual gases while providing the regenerated tertiary amine for collection and reuse in a subsequent sulfur dioxide-cleanup step. The coordinate covalent complex reacts with even very small concentrations of sulfur dioxide and reduces it to undetectable levels. Carbon dioxide in the waste-gas stream will not interfere with efficient cleanup because the selected tertiary amine does not react with it.

Klass, D.L.; Conrad, J.R.

1980-06-17

226

Sulfur plumes off Namibia  

NASA Technical Reports Server (NTRS)

Sulfur plumes rising up from the bottom of the ocean floor produce colorful swirls in the waters off the coast of Namibia in southern Africa. The plumes come from the breakdown of marine plant matter by anaerobic bacteria that do not need oxygen to live. This image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on April 24, 2002 Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

2002-01-01

227

Sulfur mobility in peat  

Microsoft Academic Search

Lead-210 chronologies, vertical S concentration gradients and ?34S values are presented for 5 Sphagnum-dominated peat bogs located in Central Europe (Rybarenska slat and Ocean Bog; Czech Republic) and the British Isles (Thorne Moors, England; Connemara, Ireland; and Mull, Scotland). Sulfur concentrations were measured in three 40-cm deep peat cores per site, sectioned into 2-cm segments. The coefficient of variation in

Martin Novák; Marie Adamová; R. Kelman Wieder; Simon H. Bottrell

2005-01-01

228

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, April-June 1983. [Thermometric titration of polysulfides with Lewis acid p-hydroxymercuribenzoate; polarography of trithionate, tetrathionate and pentathionate  

SciTech Connect

Task 1: Methods Development for the Speciation of Polysulfides. The contributions of this project in fundamental thermochemistry and thermodynamics of Lewis acid-base reactions are reviewed and summarized. The use of the reagent p-hydroxymercuribenzoate, p-HMB (/sup -/OOC phi Hg-OH), as a preferred analytical reagent for polysulfides is warranted on considerations of specificity, selectivity, and its monovalent coordination number. p-HMB is a Lewis acid-base adduct. The Lewis acidity of /sup -/OOC phi Hg/sup +/ measured as log K of a reaction with a given Lewis base was found to be 15% greater than that of the classical Lewis acid H/sub 3/CHg/sup +/. Task 2: Methods Development for the Speciation of Dithionite and Polythionates. A new electroanalytical method has been developed for the speciation of trithionate, tetrathionate, and pentathionate. Five well-resolved differential pulse polarographic peaks were obtained at the dropping mercury electrode in a mixed solvent (60% water, 40% ethanol) containing trithionate, tetrathionate, and pentathionate at comparable concentration levels. Two peaks were accounted for by the electroreduction of trithionate and tetrathionate, respectively. Pentathionate yielded three peaks. Trithionate, tetrathionate and pentathionate concentrations were linearly correlated to selected differential peak currents. Task 3: Total Accounting of the Sulfur Balance in Representative Samples of Synfuel Process Streams. Analyses of two aqueous specimens, a gasification effluent from Grand Forks, ND, and an H-Coal liquefaction process effluent were carried out. The liquefaction effluent contained predominantly hydrogen sulfide and no thiosulfate. A variety of sulfur species were observed in the gasification effluent, including thiocyanate. 9 references, 11 figures, 5 tables.

Jordan, J.; Sexton, E.; Stahl, J.; Talbott, J.; Yakupkovic, J.

1983-07-01

229

Mesoporous carbon-carbon nanotube-sulfur composite microspheres for high-areal-capacity lithium-sulfur battery cathodes.  

PubMed

Lithium-sulfur (Li-S) batteries offer theoretical energy density much higher than that of lithium-ion batteries, but their development faces significant challenges. Mesoporous carbon-sulfur composite microspheres are successfully synthesized by combining emulsion polymerization and the evaporation-induced self-assembly (EISA) process. Such materials not only exhibit high sulfur-specific capacity and excellent retention as Li-S cathodes but also afford much improved tap density, sulfur content, and areal capacity necessary for practical development of high-energy-density Li-S batteries. In addition, when incorporated with carbon nanotubes (CNTs) to form mesoporous carbon-CNT-sulfur composite microspheres, the material demonstrated superb battery performance even at a high current density of 2.8 mA/cm(2), with a reversible capacity over 700 mAh/g after 200 cycles. PMID:24090278

Xu, Terrence; Song, Jiangxuan; Gordin, Mikhail L; Sohn, Hiesang; Yu, Zhaoxin; Chen, Shuru; Wang, Donghai

2013-11-13

230

Shakedown operations in commercial production of sulfuric acid from acid tar  

Microsoft Academic Search

The authors describe process technology for processing acid tars to obtain sulfuric acid by means of high temperature splitting to regenerate spent sulfuric acid contaminated with organic impurities. An illustration presents a simplified flow plan for acid tar processing. The authors conclude, from experience with this unit, that process indexes meet design requirements, in particular with respect to the degree

V. M. Perfilev; V. B. Golyshev; A. D. Goncharenko; A. M. Shtafinskaya; V. S. Sushchev

1985-01-01

231

Process for removing sulfur from sulfur-containing gases  

DOEpatents

The present disclosure relates to i The government may own certain rights in the present invention pursuant to EPA Cooperative Agreement CR 81-1531. This is a continuation of U.S. Ser. No. 928,337, filed Nov. 7, 1986, now U.S. Pat. No. 4,804,521.

Rochelle, Gary T. (Austin, TX); Jozewicz, Wojciech (Chapel Hill, NC)

1990-01-01

232

Catalyst for the reduction of sulfur dioxide to elemental sulfur  

DOEpatents

The inventive catalysts allow for the reduction of sulfur dioxide to elemental sulfur in smokestack scrubber environments. The catalysts have a very high sulfur yield of over 90% and space velocity of 10,000 h{sup {minus}1}. They also have the capacity to convert waste gases generated during the initial conversion into elemental sulfur. The catalysts have inexpensive components, and are inexpensive to produce. The net impact of the invention is to make this technology practically available to industrial applications. 21 figs.

Jin, Y.; Yu, Q.; Chang, S.G.

1996-02-27

233

Influence of sulfurization pressure on Cu2ZnSnS4 thin films and solar cells prepared by sulfurization of metallic precursors  

NASA Astrophysics Data System (ADS)

Effects of sulfurization pressure on composition, morphology and microstructure of kesterite Cu2ZnSnS4 (CZTS) thin films obtained by sulfurization of the metallic layers have been investigated in detail. It is found that the S content in the CZTS thin films is strongly dependent on the sulfurization pressure. The CZTS thin films sulfurized under low sulfurization pressure have S-poor state with a bilayer structure, while it exhibits sufficient amounts of sulfur under high sulfurization pressure with grain growth throughout the entire absorber film. X-ray diffraction data indicate lower sulfurization pressure during the CZTS grain growth process can induce the formation of more structural defects in the CZTS lattice and the CZTS thin films sulfurized under high sulfurization pressure have more random orientation. Furthermore, ZnS and MoS2 phase exist in all samples determined by Fourier transform infrared reflectance spectroscopy as complementary to Raman spectroscopy. The solar cell fabricated with the CZTS thin film under 10 Torr sulfurization pressure shows the best conversion efficiency of 3.52% (VOC = 484 mV, JSC = 14.56 mA cm-2, FF = 50.1%).

He, Jun; Sun, Lin; Chen, Ye; Jiang, Jinchun; Yang, Pingxiong; Chu, Junhao

2015-01-01

234

Development of the Hybrid Sulfur Thermochemical Cycle  

SciTech Connect

The production of hydrogen via the thermochemical splitting of water is being considered as a primary means for utilizing the heat from advanced nuclear reactors to provide fuel for a hydrogen economy. The Hybrid Sulfur (HyS) Process is one of the baseline candidates identified by the U.S. Department of Energy [1] for this purpose. The HyS Process is a two-step hybrid thermochemical cycle that only involves sulfur, oxygen and hydrogen compounds. Recent work has resulted in an improved process design with a calculated overall thermal efficiency (nuclear heat to hydrogen, higher heating value basis) approaching 50%. Economic analyses indicate that a nuclear hydrogen plant employing the HyS Process in conjunction with an advanced gas-cooled nuclear reactor system can produce hydrogen at competitive prices. Experimental work has begun on the sulfur dioxide depolarized electrolyzer, the major developmental component in the cycle. Proof-of-concept tests have established proton-exchange-membrane cells (a state-of-the-art technology) as a viable approach for conducting this reaction. This is expected to lead to more efficient and economical cell designs than were previously available. Considerable development and scale-up issues remain to be resolved, but the development of a viable commercial-scale HyS Process should be feasible in time to meet the commercialization schedule for Generation IV gas-cooled nuclear reactors.

Summers, William A.; Steimke, John L

2005-09-23

235

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2010 CFR

...National secondary ambient air quality standard for sulfur oxides (sulfur dioxide...PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.5 National secondary ambient air quality standard for sulfur oxides (sulfur...

2010-07-01

236

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2011 CFR

...National secondary ambient air quality standard for sulfur oxides (sulfur dioxide...PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.5 National secondary ambient air quality standard for sulfur oxides (sulfur...

2011-07-01

237

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2011 CFR

...National primary ambient air quality standards for sulfur oxides (sulfur dioxide...PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.17 National primary ambient air quality standards for sulfur oxides (sulfur...

2011-07-01

238

Identification of sulfur fumed Pinelliae Rhizoma using an electronic nose  

PubMed Central

Background: Pinelliae Rhizoma is a commonly used Chinese herb which will change brown during the natural drying process. However, sulfur fumed Pinelliae Rhizoma will get a better appearance than naturally dried one. Sulfur fumed Pinelliae Rhizoma is potentially toxical due to sulfur dioxide and sulfites formed during the fuming procedures. The odor components in sulfur fumed Pinelliae Rhizoma is complex. At present, there is no analytical method available to determine sulfur fumed Pinelliae Rhizoma simply and rapidly. To ensure medication safety, it is highly desirable to have an effective and simple method to identify sulfur fumed Pinelliae Rhizoma. Materials and Methods: This paper presents a novel approach using an electronic nose based on metal oxide sensors to identify whether Pinelliae Rhizoma was fumed with sulfur, and to predict the fuming degree of Pinelliae Rhizoma. Multivariate statistical methods such as principal components analysis (PCA), discriminant factorial analysis (DFA) and partial least squares (PLS) were used for data analyzing and identification. The use of the electronic nose to discriminate between different fuming degrees Pinelliae Rhizoma and naturally dried Pinelliae Rhizoma was demonstrated. Results: The electronic nose was also successfully applied to identify unknown samples including sulfur fumed samples and naturally dried samples, high recognition value was obtained. Quantitative analysis of fuming degree of Pinelliae Rhizoma was also demonstrated. The method developed is simple and fast, which provides a new quality control method of Chinese herbs from the aspect of odor. Conclusion: It has shown that this electronic nose based metal oxide sensor is sensitive to sulfur and sulfides. We suggest that it can serve as a supportive method to detect residual sulfur and sulfides. PMID:24914293

Zhou, Xia; Wan, Jun; Chu, Liang; Liu, Wengang; Jing, Yafeng; Wu, Chunjie

2014-01-01

239

Influence of different sulfur to selenium ratios on the structural and electronic properties of Cu(In,Ga)(S,Se)2 thin films and solar cells formed by the stacked elemental layer process  

NASA Astrophysics Data System (ADS)

In this study, we investigate the effect of different elemental selenium to elemental sulfur ratios on the chalcopyrite phase formation in Cu(In,Ga)(S,Se)2 thin films. The films are formed by the stacked elemental layer process. The structural and electronic properties of the thin films and solar cells are analyzed by means of scanning electron microscopy, glow discharge optical emission spectrometry, X-ray diffraction, X-ray fluorescence, Raman spectroscopy, spectral photoluminescence as well as current-voltage, and quantum efficiency measurements. The influence of different S/(S+Se) ratios on the anion incorporation and on the Ga/In distribution is investigated. We find a homogenous sulfur concentration profile inside the film from the top surface to the bottom. External quantum efficiency measurements show that the band edge of the solar cell device is shifted to shorter wavelength, which enhances the open-circuit voltages. The relative increase of the open-circuit voltage with S/(S+Se) ratio is lower than expected from the band gap energy trend, which is attributed to the presence of S-induced defects. We also observe a linear decrease of the short-circuit current density with increasing S/(S+Se) ratio which can be explained by a reduced absorption. Above a critical S/(S+Se) ratio of around 0.61, the fill factor drops drastically, which is accompanied by a strong series resistance increase which may be attributed to changes in the back contact or p-n junction properties.

Mueller, B. J.; Zimmermann, C.; Haug, V.; Hergert, F.; Koehler, T.; Zweigart, S.; Herr, U.

2014-11-01

240

Aqueous Mercury-Sulfur and Gold-Sulfur Complexes: An In-situ EXAFS Study  

Microsoft Academic Search

Mineral and ore formation processes which involve mercury or gold often depend on aqueous speciation of these metals, and bioavailability of mercury is also affected by aqueous complexes. The nature of coordination by sulfur of these metals in aqueous solution is important for understanding the geochemical behaviour of these metals. The principal difficulty in using spectroscopy to study these heavy

A. R. Lennie; R. A. Pattrick; J. M. Charnock

2001-01-01

241

Yolk-shell structure of polyaniline-coated sulfur for lithium-sulfur batteries.  

PubMed

Lithium–sulfur batteries have attracted much attention in recent years due to their high theoretical capacity of 1672 mAh g(–1) and low cost. However, a rapid capacity fade is normally observed, attributed mainly to polysulfide dissolution and volume expansion. Although many strategies have been reported to prolong the cyclability, the high cost and complex preparation processes still hinder their practical application. Here, we report the synthesis of a polyaniline–sulfur yolk–shell nanocomposite through a heating vulcanization of a polyaniline–sulfur core–shell structure. We observed that this heating treatment was much more effective than chemical leaching to prepare uniform yolk–shell structures. Compared with its sulfur–polyaniline core–shell counterparts, the yolk–shell nanostructures delivered much improved cyclability owing to the presence of internal void space inside the polymer shell to accommodate the volume expansion of sulfur during lithiation. The yolk–shell material exhibited a stable capacity of 765 mAh g(–1) at 0.2 C after 200 cycles, representing a promising future for industrial scale Li–S batteries. PMID:24112042

Zhou, Weidong; Yu, Yingchao; Chen, Hao; DiSalvo, Francis J; Abruña, Héctor D

2013-11-01

242

Sulfur/three-dimensional graphene composite for high performance lithium-sulfur batteries  

NASA Astrophysics Data System (ADS)

A sulfur/graphene composite is prepared by loading elemental sulfur into three-dimensional graphene (3D graphene), which is assembled using a metal ions assisted hydrothermal method. When used as cathode materials for lithium-sulfur (Li-S) batteries, the sulfur/graphene composite (S@3D-graphene) with 73 wt % sulfur shows a significantly enhanced cycling performance (>700 mAh g-1 after 100 cycles at 0.1C rate with a Coulombic efficiency > 96%) as well as high rate capability with a capacity up to 500 mAh g-1 at 2C rate (3.35 A g-1). The superior electrochemical performance could be attributed to the highly porous structure of three-dimensional graphene that not only enables stable and continue pathway for rapid electron and ion transportation, but also restrain soluble polysulfides and suppress the 'shuttle effect'. Moreover, the robust structure of 3D graphene can keep cathode integrity and accommodate the volume change during high-rate charge/discharge processes, making it a promising candidate as cathode for high performance Li-S batteries.

Xu, Chunmei; Wu, Yishan; Zhao, Xuyang; Wang, Xiuli; Du, Gaohui; Zhang, Jun; Tu, Jiangping

2015-02-01

243

Petrographic and SIMS pyrite sulfur isotope analyses of Ediacaran chert nodules: Implications for microbial processes in pyrite rim formation, silicification, and exceptional fossil preservation  

NASA Astrophysics Data System (ADS)

The lower Ediacaran Doushantuo Formation in the Yangtze Gorges area contains exceptionally preserved microfossils, including the earliest known animal resting eggs and embryos. These fossils are preserved in cm-sized chert nodules, which typically have a microbial mat fragment in the center, a silica cortex, a pyrite rim, and an outer rim of blocky calcite. Petrographic analysis indicates that the formation of the blocky calcite rim postdates that of the pyrite rim and silica cortex. The pyrite rim grew centripetally during early diagenesis, representing a reaction front that was determined by the dynamics between ambient Fe 2+ and H 2S, the latter of which was derived from bacterial sulfate reduction (BSR) of mat fragment in nodule center. The silica cortex was formed pervasively through replacement of carbonate sediments prior to compaction. Secondary ion mass spectroscopy (SIMS) sulfur isotopes of individual pyrite crystals (? 34S py - SIMS) in pyrite rims and matrices show highly positive values (15.2-39.8‰). The pyrite rims do not show an isotopic gradient between small crystals formed in outer rim during early diagenesis and large crystals formed in inner rim during subsequent overgrowth. Although rim pyrite in the same chert nodule has consistent ? 34S py - SIMS values, there are significant spatial and stratigraphic variations in ? 34S py - SIMS values of both matrix and rim pyrite. Overall, isotopic fractionation between pyrite and carbonate associated sulfate (CAS) is small (< 22‰). The isotopic and petrographic data can be interpreted as evidence for rapid BSR of highly metabolizable organic matter in a diagenetic environment with limited sulfate availability, local anoxia, high Fe 2+ concentration, and low sedimentation rate. The embryonic nodules nucleated on microbial mat fragments and stayed in the BSR zone during early diagenesis, when rapid BSR in the nodule center generated outward-diffusing H 2S that was confined by readily available Fe 2+ to precipitate the pyrite rim. The precipitation of the silica cortex was facilitated by localized pH change related to BSR and pyrite precipitation, with silica sourced from silica-rich Precambrian seawater and from microbially mediated clay diagenesis. Like the pyrite rim, the silica cortex was also formed rapidly during early diagenesis, leading to the exceptional preservation of microfossils within these nodules.

Xiao, Shuhai; Schiffbauer, James D.; McFadden, Kathleen A.; Hunter, Jerry

2010-09-01

244

Biotic and abiotic carbon to sulfur bond cleavage. Final report  

SciTech Connect

The microbial desulfurization of organosulfur compounds occurs by unprecedented and largely unexplored biochemical processes. A study of such biotic desulfurizations can be expected to give rise to new and useful chemistry and enzymology. The potential value of understanding and harnessing these processes is seen in relation to the need for methods for the removal of organically bound sulfur from coal and the degradation of organic sulfur-containing pollutants. This research effort has been directed towards an examination of desulfurization ability in well characterized microorganisms, the isolation of bacteria with desulfurization ability from natural sources, the characterization and mechanistic evaluation of the observed biocatalytic processes, the development of biomimetic synthetic organic chemistry based on biotic desulfurization mechanisms and the design and preparation of improved coal model compounds for use in microbial selection processes. A systematic approach to studying biodesulfurizations was undertaken in which organosulfur compounds have been broken down into classes based on the oxidation state of the sulfur atom and the structure of the rest of the organic material. Microbes have been evaluated in terms of ability to degrade organosulfur compounds with sulfur in its sulfonic acid oxidation state. These compounds are likely intermediates in coal desulfurization and are present in the environment as persistent pollutants in the form of detergents. It is known that oxygen bonded to sulfur lowers the carbon-sulfur bond energy, providing a thermodynamic basis for starting with this class of compounds.

Frost, J.W.

1994-05-01

245

Biotransformation of sulfur and nitrogen oxides in stack gases  

SciTech Connect

The Nation`s large supply of high sulfur coal and increasingly stringent emission regulation led to priority development of advanced innovative processes for treating pollutants in flue gases from coal combustion. The principal pollutants in flue gases, sulfur oxides (SO{sub 2},SO{sub 3}) and nitrogen oxides (NO{sub x}) cause acid rain. Thus, the Department of Energy`s Clean Coal Program is funding projects to commercialize technologies that minimize emission of sulfur and nitrogen oxides at power plants. This report describes the controlled use of bioconversion processes to remove the oxides from flue gas. Two bioreactor experiments were conducted to investigate the removal of sulfur dioxide, nitrogen oxides, and carbon dioxide from stack gases.

Govind, R.; Puligadda, R. [Univ. of Cincinnati, OH (United States); Bishop, D.F. [Environmental Protection Agency, Cincinnati, OH (United States)

1995-10-01

246

In situ Raman spectroscopy of sulfur speciation in lithium-sulfur batteries.  

PubMed

In situ Raman spectroscopy and cyclic voltammetry were used to investigate the mechanism of sulfur reduction in lithium-sulfur battery slurry cathodes with 1 M lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (TEGDME)/1,3-dioxolane (DIOX) (1/1, v/v). Raman spectroscopy shows that long-chain polysulfides (S8(2-)) were formed via S8 ring opening in the first reduction process at ?2.4 V vs Li/Li(+) and short-chain polysulfides such as S4(2-), S4(-), S3(•-), and S2O4(2-) were observed with continued discharge at ?2.3 V vs Li/Li(+) in the second reduction process. Elemental sulfur can be reformed in the end of the charge process. Rate constants obtained for the appearance and disappearance polysulfide species shows that short-chain polysulfides are directly formed from S8 decomposition. The rate constants for S8 reappearance and polysulfide disappearance on charge were likewise similar. The formation of polysulfide mixtures at partial discharge was found to be quite stable. The CS2 additive was found to inhibit the sulfur reduction mechanism allowing the formation of long-chain polysulfides during discharge only and stabilizing the S8(2-) product. PMID:25543831

Wu, Heng-Liang; Huff, Laura A; Gewirth, Andrew A

2015-01-28

247

SYNTHESIS OF SULFUR-BASED WATER TREATMENT AGENT FROM SULFUR DIOXIDE WASTE STREAMS  

SciTech Connect

We propose a process that uses sulfur dioxide from coal combustion as a raw material to synthesize polymeric ferric sulfate (PFS), a water treatment agent. The process uses sodium chlorate as an oxidant and ferrous sulfate as an absorbent. The major chemical mechanisms in this reaction system include oxidation, hydrolysis, and polymerization. Oxidation determines sulfur conversion efficiency while hydrolysis and polymerization control the quality of product. Many factors, including SO{sub 2} inlet concentration, flow rate of simulated flue gas, reaction temperature, addition rate of oxidant and stirring rate, may affect the efficiencies of SO{sub 2} removal. Currently, the effects of SO{sub 2} inlet concentration, the flow rate of simulated flue gas and addition rate of flue gas on removal efficiencies of SO{sub 2}, are being investigated. Experiments shown in this report have demonstrated that the conversion efficiencies of sulfur dioxide with ferrous sulfate as an absorbent are in the range of 60-80% under the adopted process conditions. However, the conversion efficiency of sulfur dioxide may be improved by optimizing reaction conditions to be investigated. Partial quality indices of the synthesized products, including Fe{sup 2+} concentration and total iron concentration, have been evaluated.

Robert C. Brown; Maohong Fan

2001-12-01

248

Electroanalytical Chemistry of Sulfur Compounds For the New Coal Conversion Technologies  

Microsoft Academic Search

Polarographic methods are described “tailor-made” for the speciation and determination of sulfur contaminants in synfuels and coal gasification\\/liquefaction process streams. In samples containing the anions, S x, sulfidic sulfur was quantitated by anodic depolarization of the dropping mercury electrode, while polysulfidic sulfur was determined with the aid of an electroreduction process implicating 2(x-1) electrons. Polythionates were electroreduced to thiosulfate, sulfite,

Joseph Jordan; Jonathan Talbott; Joseph Yakupkovic

1989-01-01

249

Membranes for the Sulfur-Iodine Integrated Laboratory Scale Demonstration  

SciTech Connect

INL has developed polymeric membrane-based chemical separations to enable the thermochemical production of hydrogen. Major activities included studies of sulfuric acid concentration membranes, hydriodic acid concentration membranes, SO2/O2 separation membranes, potential applications of a catalyst reactor system for the decomposition of HI, and evaluation of the chemical separation needs for alternate thermochemical cycles. Membranes for the concentration of sulfuric acid were studied using pervaporation. The goal of this task was to offer the sulfur-iodine (S-I) and the hybrid sulfur (HyS) cycles a method to concentrate the sulfuric acid containing effluent from the decomposer without boiling. In this work, sulfuric acid decomposer effluent needs to be concentrated from ~50 % acid to 80 %. This task continued FY 2006 efforts to characterize water selective membranes for use in sulfuric acid concentration. In FY 2007, experiments were conducted to provide specific information, including transmembrane fluxes, separation factors, and membrane durability, necessary for proper decision making on the potential inclusion of this process into the S-I or HyS Integrated Laboratory Scale demonstration.

Frederick F. Stewart

2007-08-01

250

8, 93479404, 2008 Sulfur isotope  

E-print Network

ACPD 8, 9347­9404, 2008 Sulfur isotope analyses of individual aerosol particles B. Winterholler et the Creative Commons Attribution 3.0 License. Atmospheric Chemistry and Physics Discussions Sulfur isotope isotope analyses of individual aerosol particles B. Winterholler et al. Title Page Abstract Introduction

Paris-Sud XI, Université de

251

Demonstrating Allotropic Modifications of Sulfur.  

ERIC Educational Resources Information Center

Shows how a common demonstration that consists of slowly heating sulfur powder in a test tube to illustrate sulfur's allotropic modifications can convince students of conclusions about the moon Io which they often find surprising. Describes the demonstration in full. (Author/MM)

McCarty, Jillian L.; Dragojlovic, Veljko

2002-01-01

252

SULFUR RETENTION IN COAL ASH  

EPA Science Inventory

The report gives results of an analytical study to assess the potential for sulfur retention in various types of coal-fired boilers. Results of a field test of 10 industrial coal-fired boilers were used to evaluate the impact on sulfur retention of the operating variables (load a...

253

Research and development in the field of sodium sulfur batteries: Long lifetime beta alumina electrolytes prepared according to an optimized spray decomposition process  

NASA Astrophysics Data System (ADS)

An alternative process to solid state reaction of carbonates and oxides for the production of beta Al203 was established. The process involves thermal decomposition of nitrate solutions, i.e., spray decomposition. Ceramics of a fine-grained structure and with a homogeneous distribution of the components were then made from powders produced by this process. Tubes prepared from this powder show long lifetimes without degradation in Na/beta Al203/Na cells, even at current densities of up to 200 mA/sq cm.

Knoedler, R.; Ammende, S.; Beck, H. P.; Klawik, R.; Kuan, W.; Merz, F.

1980-07-01

254

The shadow price of substitutable sulfur in the US electric power plant: a distance function approach.  

PubMed

Given restrictions on sulfur dioxide emissions, a feasible long-run response could involve either an investment in improving boiler fuel-efficiency or a shift to a production process that is effective in removing sulfur dioxide. To allow for the possibility of substitution between sulfur and productive capital, we measure the shadow price of sulfur dioxide as the opportunity cost of lowering sulfur emissions in terms of forgone capital. The input distance function is estimated with data from 51 coal-fired US power units operating between 1977 and 1986. The indirect Morishima elasticities of substitution indicate that the substitutability of capital for sulfur is relatively high. The overall weighted average estimate of the shadow price of sulfur is -0.076 dollars per pound in constant 1976 dollars. PMID:15993533

Lee, Myunghun

2005-10-01

255

Improve operations and enhance refinery sulfur recovery  

SciTech Connect

Sulfur is a common contaminant in fossil fuels, released when these fuels are combusted. It causes acid rain and other environmental problems. Sulfur emissions have gained worldwide attention, resulting in tighter requirements for sulfur recovery facilities. New technologies and enhancements to existing technologies have emerged as a result. This overview presents many technologies used for sulfur recovery. It is organized around the unit operations of gas and liquid sweetening, sour water stripping, sulfur recovery, sulfur degassing and solidification, tail gas treating, and incineration. New technical and equipment innovations have resulted in sulfur recovery facilities that are more reliable, recover more sulfur, are easier to operate, and reduce capital and operating costs.

Bourdon, J.C. [Black and Veatch Pritchard, Inc., Overland Park, KS (United States)

1997-04-01

256

Cycling of sulfur in subduction zones: The geochemistry of sulfur in the Mariana Island Arc and back-arc trough  

USGS Publications Warehouse

The sulfur contents and sulfur isotopic compositions of 24 glassy submarine volcanics from the Mariana Island Arc and back-arc Mariana Trough were determined in order to investigate the hypothesis that subducted seawater sulfur (??34S = 21???) is recycled through arc volcanism. Our results for sulfur are similar to those for subaerial arc volcanics: Mariana Arc glasses are enriched in 34S (??34S = up to 10.3???, mean = 3.8???) and depleted in S (20-290 ppm, mean = 100 ppm) relative to MORB (850 ppm S, ??34S = 0.1 ?? 0.5???). The back-arc trough basalts contain 200-930 ppm S and have ??34S values of 1.1 ?? 0.5???, which overlap those for the arc and MORB. The low sulfur contents of the arc and some of the trough glasses are attributed to (1) early loss of small amounts of sulfur through separation of immiscible sulfide and (2) later vapor-melt equilibrium control of sulfur contents and loss of sulfur in a vapor phase from sulfide-undersaturated melts near the minimum in sulfur solubility at f{hook}O2 ??? NNO (nickel-nickel oxide). Although these processes removed sulfur from the melts their effects on the sulfur isotopic compositions of the melts were minimal. Positive trends of ??34S with 87Sr 86Sr, LILE and LREE contents of the arc volcanics are consistent with a metasomatic seawater sulfur component in the depleted sub-arc mantle source. The lack of a 34S-rich slab signature in the trough lavas may be attributed to equilibration of metasomatic fluid with mantle material along the longer pathway from the slab to the source of the trough volcanics. Sulfur is likely to have been transported into the mantle wedge by metasomatic fluid derived from subducted sediments and pore fluids. Gases extracted from vesicles in arc and back-arc samples are predominantly H2O, with minor CO2 and traces of H2S and SO2. CO2 in the arc and back-arc rocks has ??13C values of -2.1 to -13.1???, similar to MORB. These data suggest that degassing of CO2 could explain the slightly lower ??13C values for some Mariana Trough volcanic glasses, and that incorporation of subduction-derived organic carbon into the Mariana Trough mantle source may not be necessary. More analyses are required to resolve this question, however. ?? 1993.

Alt, J.C.; Shanks, W. C., III; Jackson, M.C.

1993-01-01

257

Sulfur speciation in hard coal by means of a thermal decomposition method.  

PubMed

A new method for the determination of organic and pyritic sulfur in hard coal is presented. The method is based on controlled thermal decomposition of coal sample in oxygen-free and oxygen atmospheres. The results for sulfur liberated in an argon atmosphere at temperatures up to 773 K were close to organic sulfur contents (Sorg), although owing to the definition of 'organic sulfur' the values were not directly comparable. Sorg contents are calculated from the difference between total sulfur content in coal and contents of this element in the form of sulfides, sulfates and pyrites. Sulfur contents, found in the second stage of analysis, were close to pyritic sulfur contents. The difference between total sulfur content and the sum of sulfur values obtained in stages I and II corresponded to sulfur contents in those samples which were neither decomposed nor oxidized at temperatures up to 1173 K. Although not comparable with such conventional concepts for industrial purposes these data are attractive due to the ease and rapidity of the new method for the control of sulfur streams in industrial processes. PMID:11939541

Spiewok, W; Ciba, J; Trojanowska, J

2002-02-01

258

Sulfur: The plankton/climate connection  

SciTech Connect

A key process in the global sulfur cycle is the transfer of volatile forms of the element from sea to land via the atmosphere. Early budgets calculated the amount of sulfur required to balance the cycle and generally assumed that this flux was achieved by formation of hydrogen sulfide (H[sub 2]S) in coastal waters, mud flats, etc. However, Lovelock et al. (1972) made the first field measurements of dimethylsulfide (DMS) in seawater and suggested that it represented the missing link in the S cycle. Other sulfur gases, such as carbonylsulfide (COS), carbon disulfide (CS[sub 2]), methylmercaptan (CH[sub 3]SH), and dimethyldisulfide (CH[sub 3]SSCH[sub 3]), are also often observed, but DMS is usually dominant (Andreae et al. 1983, Cline and Bates 1983, Turner and Liss 1985). Over the past decade or so thousands of analyses have been made covering coastal, shelf, and open ocean environments, which show that DMS is ubiquitous in seawater but that considerable spatial and temporal variability occurs (see Cooper and Matrai 1989). In this review the authors consider processes leading to the formation of DMS in seawater, its emission to the atmosphere, and transformations therein, the possible role of DMS oxidation products in climate regulation as proposed by Charlson et al. (1987), and how global changes might affect DMS production. 80 refs., 2 figs.

Malin, G.; Turner, S.M.; Liss, P.S. (Univ. of East Anglia, Norwich (United Kingdom))

1992-10-01

259

PILOT PLANT STUDY OF CONVERSION OF COAL TO LOW SULFUR FUEL  

EPA Science Inventory

The report gives results of a program to develop, on bench and pilot scales, operating conditions for the key step in the IGT process to desulfurize coal by thermal and chemical treatment. This process, to date, uses the 'sulfur-getter' concept. (A sulfur-getter is a material tha...

260

[Morpho-functional characteristics of reproductive organs of rodents from the area affected by a plant, processing gas with the increased content of sulfur compounds].  

PubMed

The biology of reproduction of 5 rodent species--small gopher (Spermophilus pygmaeus Pallas, 1778), reddish gopher (Spermophilus major Pallas, 1779), sasin lemmer (Lagurus lagurus Pallas,1773), forest mouse (Apodemus sylvaticus Linnaeus) and bank vole(Clethrionomys glareolus Schreber, 1780)--inhabiting the sanitary protective zone of the gas processing plant, was investigated with the use of histological, electron microscopical, immunocytochemical and morphometric methods. Intensification of the reproduction (growth of female fecundity, reduction of the puberty age) in some species (forest mouse) compensated for the negative changes in the reproduction, which resulted from the influence of the industrial factors (premature loss of ovarian follicular reserve, accelerated embryonic death rate, increased destructive changes in the gonads) and provided for the preservation of the population sizes. The intense functioning of reproductive organs in the other species (small and reddish gophers) was insufficient to compensate for the damage inflicted by the man-caused actions. PMID:19102254

Shevliuk, N N; Blinova, E V; Bokov, D A; Demina, L L

2008-01-01

261

Graphene-sulfur nanocomposites for rechargeable lithium-sulfur battery electrodes  

SciTech Connect

Rechargeable lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter less than 50 nm..

Liu, Jun; Lemmon, John P; Yang, Zhenguo; Cao, Yuiliang; Li, Xiaolin

2014-06-17

262

Sugar yields from dilute sulfuric acid and sulfur dioxide pretreatments and subsequent enzymatic hydrolysis of switchgrass  

E-print Network

Sugar yields from dilute sulfuric acid and sulfur dioxide pretreatments and subsequent enzymatic Dilute sulfuric acid Sulfur dioxide Biofuels Switchgrass a b s t r a c t Dacotah switchgrass was pretreated with sulfuric acid concentrations of 0.5, 1.0, and 2.0 wt.% at 140, 160, and 180 °C and with 1

California at Riverside, University of

263

Sulfur Dioxide Crossover during the Production of Hydrogen and Sulfuric Acid in a PEM Electrolyzer  

E-print Network

Sulfur Dioxide Crossover during the Production of Hydrogen and Sulfuric Acid in a PEM Electrolyzer in the thermochemical conversion of sulfur dioxide to sulfuric acid for the large-scale production of hydrogen-17 In this thermochemical cycle, sulfuric acid is decomposed at high temperature 850°C to SO2 and wa- ter, and the SO2

Weidner, John W.

264

Thermal behavior of the sulfur electrolyte in sodium-sulfur battery concepts  

SciTech Connect

The composition range and the temperature limits for the sulfur electrolyte in sodium-sulfur battery concepts extends from the molten polysulfide phase into and through the region of molten pulse-molten sulfur phase separation, to elemental sulfur. Investigations of the thermal behavior of the sulfur electrolyte (melting-crystallizatio

Janz, G.J.; Rogers, D.J.

1983-01-01

265

Toxicology of sulfur in ruminants: review  

SciTech Connect

This review deals with the toxicology of sulfur in ruminants including toxicity, neurotoxic effects, and mechanism of toxic action of hydrogen sulfide, clinical signs, and treatment. It will report effects of excessive intake of sulfur by ruminants on feed intake, animal performance, ruminal digestion and motility, rumination, and other physiological functions. Poisoning of animals with sulfur from industrial emissions (sulfur dioxide) also is discussed. Excessive quantities of dietary sulfur (above .3 to .4%) as sulfate or elemental sulfur may cause toxic effects and in extreme cases can be fatal. The means is discussed whereby consumption of excessive amounts of sulfur leads to toxic effects. 53 references, 1 table.

Kandylis, K.

1984-10-01

266

Sulfur-Free Selective Pulping  

E-print Network

A joint research effort is being conducted on ways to produce cost-effective pulping catalysts from lignin. This project addresses improving selectivities and reducing the levels of sulfur chemicals used in pulping. Improved selectivity means...

Dimmel, D. R.; Bozell, J. J.

267

Photometric properties of powdered sulfur  

NASA Astrophysics Data System (ADS)

Particle size, temperature, thermal history, and scattering geometry are shown by the present laboratory investigation of the spectrophotometric properties of three particle-size fractions of sulfur to influence the spectral reflectance of both normal and quenched molten samples of sulfur. A scattering law that consists of a linear combination of lunar-like and Lambertian terms adequately describes the data for all particle sizes. Near opposition, sulfur particles closely follow a Minnaert limb darkening law except where the reflectance is low, as in the strong UV absorption band of the larger particle size fractions. The present data indicate that quantitative comparisons between disk-integrated observations of Io and laboratory measurements of flat sulfur samples are inadequate unless temperature effects and scattering geometry changes are included.

Gradie, J.; Veverka, J.

1984-05-01

268

Radiolysis of sulfuric acid, sulfuric acid monohydrate, and sulfuric acid tetrahydrate and its relevance to Europa  

Microsoft Academic Search

We report laboratory studies on the 0.8MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4·H2O), and sulfuric acid tetrahydrate (H2SO4·4H2O) between 10 and 180K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4-, and SO42-. At high radiation doses, we find that H2SO4 molecules are destroyed completely and that

M. J. Loeffler; R. L. Hudson; M. H. Moore; R. W. Carlson

2011-01-01

269

Coal Liquefaction desulfurization process  

DOEpatents

In a solvent refined coal liquefaction process, more effective desulfurization of the high boiling point components is effected by first stripping the solvent-coal reacted slurry of lower boiling point components, particularly including hydrogen sulfide and low molecular weight sulfur compounds, and then reacting the slurry with a solid sulfur getter material, such as iron. The sulfur getter compound, with reacted sulfur included, is then removed with other solids in the slurry.

Givens, Edwin N. (Bethlehem, PA)

1983-01-01

270

Zirconium in sulfuric acid applications  

SciTech Connect

Zirconium is one of the few metals that resists attack by sulfuric acid at concentrations up to 75% and temperatures to boiling and above. This capability makes zirconium a good structural metal for use in 40 to 65% H/sub 2/SO/sub 4/ up to boiling temperatures and for weak acid concentrations at elevated temperatures. Zirconium's corrosion properties in sulfuric acid solutions are compared with nickel base alloys. Examples of applications and limitations in the use of zirconium are presented.

Webster, R.T.; Yau, T.L.

1986-02-01

271

Analysis for sulfur forms in coal and on coal surfaces  

SciTech Connect

A review and critical evaluation of all available literature on the determination of sulfur and sulfur forms in coal and on coal and pyrite surfaces is being performed. Approximately 200 citations through 1984 have been catalogued and reviewed, and approximately 100 additional citations since 1984 have been identified. Work is nearing completion on the collection and critical evaluation of the more recent literature. A few articles requested through the interlibrary loan system still need to be received and analyzed, and several articles in unusual foreign languages need to be evaluated. Methods used for sampling, sample preparation, and analysis of sulfur and sulfur forms in samples arising from the spherical oil agglomeration process have been reviewed. Recommendations are being made for assessing the quality of analyses provided by commercial laboratories, for assuring that preparation procedures do not alter sulfur forms in samples, and for determining the ability of sampling procedures to obtain representative samples. Several concerns about the applicability of the ASTM procedure for the determination of pyrite sulfur in micronized coal and oil-agglomerated samples have been raised. 5 refs., 1 tab.

Markuszewski, R.; Chriswell, C.D.; Norton, G.A.

1988-12-01

272

SULFUR (S) Role of S in plants  

E-print Network

SULFUR #12;SULFUR (S) · Role of S in plants Component of amino acids Essential for nitrate sulfur #12;Sulfur Removed by Crops Portion Sulfur Crop harvested Yield/acre removed -- lb/acre -- Alfalfa S/a for 1% OM · S in rain & snow ­ 10 or 20 lb S/a · S in subsoil 5, 10, or 20 lb S/a · S in manure

Balser, Teri C.

273

An economic analysis of microbial reduction of sulfur dioxide as a means of byproduct recovery from regenerable processes for flue gas desulfurization  

SciTech Connect

We have previously demonstrated that the sulfate-reducing bacterium, Desulfovibrio desulfuricans, may be grown in mixed culture with fermentative heterotrophs in a medium in which glucose served as the only carbon source. Beneficial cross-feeding resulted in vigorous growth of D. desulfuricans, which used SO{sub 2} (1% SO{sub 2}, 5% CO{sub 2}, balance N{sub 2}) as a terminal electron acceptor with complete reduction of SO{sub 2} to H{sub 2}S with only 1-2 s of contact time. Sulfate-reducing bacteria (SRB) cannot use simple sugars (such as glucose) as carbon and energy sources. However, the fermentative heterotrophs that developed in these cultures as a result of septic operation utilized glucose and produced fermentative end products (ethanol and lactic acid), which served as carbon and energy sources for D. desulfuricans. Sulfate-reducing bacteria are also strict anaerobes; mere exclusion of oxygen is not sufficient to support growth of pure cultures. Redox-poising agents are generally required to maintain a redox potential in the medium of - 150 to - 250 mV. However, in D. desulfuricans working cultures, no redox-poising agents were required. This report compares the process economics of microbial desulfurization with conventional desulfurization techniques.

Sublette, K.L.; Gwozdz, K.J. [Univ. of Tulsa, OK (United States); [ABB Lummus Crest Inc., Bloomfield, NJ (United States)

1991-12-31

274

METHOD TO PREVENT SULFUR ACCUMULATION INSIDE MEMBRANE ELECTRODE ASSEMBLY  

SciTech Connect

HyS is conceptually the simplest of the thermochemical cycles and involves only sulfur chemistry. In the HyS Cycle hydrogen gas (H{sub 2}) is produced at the cathode of the electrochemical cell (or electrolyzer). Sulfur dioxide (SO{sub 2}) is oxidized at the anode to form sulfuric acid (H{sub 2}SO{sub 4}) and protons (H{sup +}) as illustrated below. A separate high temperature reaction decomposes the sulfuric acid to water and sulfur dioxide which are recycled to the electrolyzers, and oxygen which is separated out as a secondary product. The electrolyzer includes a membrane that will allow hydrogen ions to pass through but block the flow of hydrogen gas. The membrane is also intended to prevent other chemical species from migrating between electrodes and undergoing undesired reactions that could poison the cathode or reduce overall process efficiency. In conventional water electrolysis, water is oxidized at the anode to produce protons and oxygen. The standard cell potential for conventional water electrolysis is 1.23 volts at 25 C. However, commercial electrolyzers typically require higher voltages ranging from 1.8 V to 2.6 V [Kirk-Othmer, 1991]. The oxidation of sulfur dioxide instead of water in the HyS electrolyzer occurs at a much lower potential. For example, the standard cell potential for sulfur dioxide oxidation at 25 C in 50 wt % sulfuric acid is 0.29 V [Westinghouse, 1980]. Since power consumption by the electrolyzers is equal to voltage times current, and current is proportional to hydrogen production, a large reduction in voltage results in a large reduction in electrical power cost per unit of hydrogen generated.

Steimke, J.; Steeper, T.; Herman, D.; Colon-Mercado, H.; Elvington, M.

2009-06-22

275

Production of elemental sulfur from H{sub 2}S and CO{sub 2} derived from a coal desulfurization process. Quarterly technical process report, April 1, 1994--June 30, 1994  

SciTech Connect

During the third quarter of this project, by using the apparatus previously setup for preparation of catalysts, the CoO-MoO{sub 3}-Al{sub 2}O{sub 3} catalyst was prepared and the thermal stability of the catalyst was tested. Efforts were made on the calibration and the programming of the two column GC of a Perkin Elmer Gas Chromatograph. Column A was used for detecting sulfur related substances such as H{sub 2}S, COS and CS{sub 2}, and column B was for CO, CH{sub 4} and H{sub 2}. All of the GC standard curves were obtained. Non-catalytic experiments were carried out by using the packed bed reactor system with blank, filled only with quartz wool and Al{sub 2}O{sub 3} support for future reference. A modified new reactor was designed to quickly quench the reaction and to prohibit the occurrence of re-equilibration of reaction products. Further thermodynamic analyses for the reaction of H{sub 2}S and CO, were performed using the Stanjan method.

Hu, Longsheng; Jiang, Xueyu; Khang, Soon-Jai

1994-08-01

276

Sulfur recovery hiked in Claus/ Sulfreen units at Ram River  

SciTech Connect

Extensive work at the Ram River gas plant has been directed at increasing sulfur-recovery efficiency. Recently, emphasis has been on reducing the emission contribution of COS/CS/sub 2/ and improving Sulfreen plant operation. In 1983, recovery efficiency reached 98.7%. Present contribution by residual sulfur components to plant emissions are: H/sub 2/S/SO/sub 2/ 39%, COS/CS/sub 2/ 28%, ratio upsets 17%, sulfur vapor 12%, and the Sulfreen regeneration process 4%. The Ram River plant processes sour natural gas from 12 different pools, with a maximum H/sub 2/S content of 39%. Inlet capacity is 17.7 million cu m/day of raw gas, with an output of 12 million cu m/day of sales gas, 300 cu m/day of pentanes plus, and 4,600 tons/day of sulfur from the diethanolamine (DEA) sweetening process. The plant facility comprises two stages, each consisting of two highpressure DEA gas sweetening trains, two 1,150-ton/day sulfur plants, a Sulfreen tail gas clean-up unit, and an incinerator. Effluent from both Sulfreen incinerators is released through a common stack. A low-pressure gas sweetening unit was added in 1980 to handle increased flash gas due to a 50% increase in the load on the high-pressure DEA units.

Coward, R.S.; Skaret, W.M.

1985-04-08

277

Hydrogen and sulfur recovery from hydrogen sulfide wastes  

DOEpatents

A process for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

Harkness, John B. L. (Naperville, IL); Gorski, Anthony J. (Woodridge, IL); Daniels, Edward J. (Oak Lawn, IL)

1993-01-01

278

Biotic and abiotic carbon to sulfur bond cleavage. Technical report, July 1, 1991--September 30, 1991  

SciTech Connect

Cleavage of aliphatic organosulfonate carbon to sulfur (C-S) bonds, a critical link in the global biogeochemical sulfur cycle, has been identified in Escherichia coli K-12. Enormous quantities of inorganic sulfate are continuously converted (Scheme I) into methanesulfonic acid 1 and acylated 3-(6-sulfo-{alpha}-D-quinovopyranosyl)-L-glycerol 2. Biocatalytic desulfurization (Scheme I) of 1 and 2, which share the structural feature of an aliphatic carbon bonded to a sulfonic acid sulfur, completes the cycle, Discovery of this desulfurization in E. coli provides an invaluable paradigm for study of a biotic process which, via the biogeochemical cycle, significantly influences the atmospheric concentration of sulfur-containing molecules.

Frost, J.W.

1991-12-31

279

Improving sulfur recovery at GPM`s Goldsmith Gas Plant  

SciTech Connect

A conventional 3-stage Claus sulfur recovery unit located in GPM Gas Corporation`s Goldsmith Gas Plant was successfully converted to a sub-dewpoint process plant using Amoco`s Cold Bed Adsorption (CBA) technology. The sulfur recovery efficiency was raised from about 96% to more than 98%. This allowed plant throughput to nearly double without increasing sulfur dioxide (SO{sub 2}) emissions. Essentially all existing equipment items were reused in the CBA process retrofit. The conversion required the addition of a new reactor, modification of the existing third bed to serve as a CBA reactor, replacement of the last sulfur condenser, and the addition of a unique, cost-effective heater to regenerate the CBA beds. Some existing equipment items were modified and/or replaced to improve the overall economics and reliability of the operation, and the sulfur recovery unit instrumentation was converted to distributed control system (DCS) control. Proven, highly reliable sulfur vapor valve assemblies were added to allow the existing third bed and the new reactor to cycle as CBA beds, with the DCS controlling these switching valves. The project team included Ortloff Engineers, LTD, area contractors, and GPM`s technical, purchasing, inspection, and maintenance personnel. Time from project approval and kickoff through startup was less than 12 months. Careful coordination of the conceptual design, detailed design, procurement, HAZOP, operator training, shutdown, and startup phases resulted in a very successful fast-track project. The Goldsmith Gas Plant is no longer capacity-limited by the SO{sub 2} emission rate from the sulfur recovery unit.

Grigson, S.M.; Rambo, C.L.; Hudson, H.M. [Ortloff Engineers, Ltd., Midland, TX (United States); Hahn, P.R. [GPM Gas Corp., Odessa, TX (United States)

1997-12-31

280

Characterization and differential expression of microRNAs elicited by sulfur deprivation in Chlamydomonas reinhardtii  

PubMed Central

Background microRNAs (miRNAs) have been found to play an essential role in the modulation of numerous biological processes in eukaryotes. Chlamydomonas reinhardtii is an ideal model organism for the study of many metabolic processes including responses to sulfur-deprivation. We used a deep sequencing platform to extensively profile and identify changes in the miRNAs expression that occurred under sulfur-replete and sulfur-deprived conditions. The aim of our research was to characterize the differential expression of Chlamydomonas miRNAs under sulfur-deprived conditions, and subsequently, the target genes of miRNA involved in sulfur-deprivation were further predicted and analyzed. Results By using high-throughput sequencing, we characterized the microRNA transcriptomes under sulphur-replete and sulfur-deprived conditions in Chlamydomonas reinhardtii. We predicted a total of 310 miRNAs which included 85 known miRNAs and 225 novel miRNAs. 13 miRNAs were the specific to the sulfur-deprived conditions. 47 miRNAs showed significantly differential expressions responding to sulfur-deprivation, and most were up-regulated in the small RNA libraries with sulfur-deprivation. Using a web-based integrated system (Web MicroRNAs Designer 3) and combing the former information from a transcriptome of Chlamydomonas reinhardtii, 22 miRNAs and their targets involved in metabolism regulation with sulfur-deprivation were verified. Conclusions Our results indicate that sulfur-deprivation may have a significant influence on small RNA expression patterns, and the differential expressions of miRNAs and interactions between miRNA and its targets might further reveal the molecular mechanism responding to sulfur-deprivation in Chlamydomonas reinhardtii. PMID:22439676

2012-01-01

281

Correlation of Sulfuric Acid Hydrate Abundance with Charged Particle Flux at the Surface of Europa  

NASA Astrophysics Data System (ADS)

The trailing hemisphere of Jupiter's moon Europa is bombarded by charged particles trapped within Jupiter's magnetosphere. Sulfur ion implantation and impacting energetic electrons strongly affect the surface chemistry of Europa. Understanding these processes is important for disentangling the extrinsic and intrinsic components of Europa's surface chemistry. In the sulfur cycle model of Carlson et al. (Science 286, 97, 1999), hydrated sulfuric acid represents the dominant reaction product of radiolytic surface modification processes on Europa. In recent compositional investigations employing linear mixture modeling, Dalton et al. (LPSC XV, #2511, 2009) and Shirley et al. (Icarus, in press, 2010) document a well-defined gradient of hydrated sulfuric acid abundance for a study area spanning the leading side - trailing side boundary in Argadnel Regio. Sulfuric acid hydrate abundance in this region increases toward the trailing side apex. Here we compare the derived sulfuric acid hydrate abundances at 41 locations on Europa's surface with independent model results describing 1) the sulfur ion flux (Hendrix et al., 2010, in preparation), and 2) the energetic electron flux, at the same locations. We improve upon the prior calculation of electron energy into the surface of Paranicas et al. (2009, in Europa, U. Arizona, p529; Pappalardo, McKinnon, & Khurana eds.) by incorporating a realistic pitch angle dependence of the distribution. While the sulfur ion implantation and electron energy deposition model distributions differ in important details, both show trailing side gradients similar to that found for the sulfuric acid hydrate. Correlation coefficients exceed 0.9 in comparisons of each of these models with the sulfuric acid hydrate distribution. Our results support models in which the electron energy flux drives reactions that utilize implanted sulfur to produce sulfuric acid hydrate. This work was performed at the California Institute of Technology-Jet Propulsion Laboratory under contract with NASA's Outer Planets Research Program.

Dalton, James B.; Paranicas, C. P.; Cassidy, T. A.; Shirley, J. H.

2010-10-01

282

Correlation of Sulfuric Acid Hydrate Abundance with Charged Particle Flux at the Surface of Europa  

Microsoft Academic Search

The trailing hemisphere of Jupiter's moon Europa is bombarded by charged particles trapped within Jupiter's magnetosphere. Sulfur ion implantation and impacting energetic electrons strongly affect the surface chemistry of Europa. Understanding these processes is important for disentangling the extrinsic and intrinsic components of Europa's surface chemistry. In the sulfur cycle model of Carlson et al. (Science 286, 97, 1999), hydrated

James B. Dalton; C. P. Paranicas; T. A. Cassidy; J. H. Shirley

2010-01-01

283

Enhanced hydrogen production from biomass via the sulfur redox cycle under hydrothermal conditions  

Microsoft Academic Search

A new method of hydrogen production from biomass via a sulfur redox cycle at moderate temperatures has been proposed. This method, which can utilize excess sulfur from hydrocarbon refining processes and waste or geothermal heat, consists of two half cycles: (1) hydrogen production from an aqueous alkaline solution at subcritical conditions of water, where sulfide, HS? and S2?, acts as

Putri Setiani; Javier Vilcáez; Noriaki Watanabe; Atsushi Kishita; Noriyoshi Tsuchiya

2011-01-01

284

Specific gravity and API gravity of biodiesel and ultra-low sulfur diesel (ULSD) blends  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biodiesel is an alternative fuel made from vegetable oils and animal fats. In 2006, the U. S. Environmental Protection Agency mandated a maximum sulfur content of 15 ppm in on-road diesel fuels. Processing to produce the new ultra-low sulfur petrodiesel (ULSD) alters specific gravity (SG) and othe...

285

Sulfur Chemistry in the Early and Present Atmosphere of Mars  

NASA Technical Reports Server (NTRS)

Atmospheric sulfur species resulting from volcanic emissions impact the composition and chemistry of the atmosphere, impact the climate, and hence, the habitability of Mars and impact the mineralogy and composition of the surface of Mars. The geochemical/ photochemical cycling of sulfur species between the interior (via volcanism), the atmosphere (atmospheric photochemical and chemical processes) and the deposition of sulfuric acid on the surface of Mars is an important, but as yet poorly understood geochemical/ photochemical cycle on Mars. There is no observational evidence to indicate that Mars is volcanically active at the present time, however, there is strong evidence that volcanism was an important and widespread process on early Mars. The chemistry and photochemistry of sulfur species in the early and present atmosphere of Mars will be assessed using a one-dimensional photochemical model. Since it is generally assumed that the atmosphere of early Mars was significantly denser than the present 6-millibar atmosphere, photochemical calculations were performed for the present atmosphere and for the atmosphere of early Mars with assumed surface pressures of 60 and 350-millibars, where higher surface pressure resulted from enhanced atmospheric concentrations of carbon dioxide (CO2). The following sections include the results of earlier modeling studies, a summary of the one-dimensional photochemical model used in this study, a summary of the photochemistry and chemistry of sulfur species in the atmosphere of Mars and some of the results of the calculations.

Levine, Joel S.; Summers, M. E.

2011-01-01

286

The sulfurized InP surface  

SciTech Connect

Sulfur treatments have previously been shown to improve the electrical characteristics of InP and GaAs devices. This paper reports the results of an Auger/x-ray photoelectron spectroscopy investigation of the InP surface after sulfur treatment. It is shown that the sulfur remains on the surface bonded to indium. There is no indication of elemental sulfur or sulfur bonded to phosphorus. This suggests that the sulfur has replaced phosphorus on the surface and has filled the phosphorus vacancies.

Wilmsen, C. W.; Geib, K. M.; Shin, J.; Iyer, R.; Lile, D. L.; Pouch, J. J.

1989-07-01

287

Advanced byproduct recovery: Direct catalytic reduction of sulfur dioxide to elemental sulfur. Fourth quarterly technical progress report  

SciTech Connect

The team of Arthur D. Little, Tufts University and Engelhard Corporation are conducting Phase 1 of a four and a half year, two-phase effort to develop and scale-up an advanced byproduct recovery technology that is a direct, single-stage, catalytic process for converting sulfur dioxide to elemental sulfur. This catalytic process reduces SO{sub 2} over a fluorite-type oxide (such as ceria and zirconia). The catalytic activity can be significantly promoted by active transition metals, such as copper. More than 95% elemental sulfur yield, corresponding to almost complete sulfur dioxide conversion, was obtained over a Cu-Ce-O oxide catalyst as part of an on-going DOE-sponsored, University Coal Research Program. This type of mixed metal oxide catalyst has stable activity, high selectivity for sulfur production, and is resistant to water and carbon dioxide poisoning. Tests with CO and CH{sub 4} reducing gases indicate that the catalyst has the potential for flexibility with regard to the composition of the reducing gas, making it attractive for utility use. The performance of the catalyst is consistently good over a range of SO{sub 2} inlet concentration (0.1 to 10%) indicating its flexibility in treating SO{sub 2} tail gases as well as high concentration streams.

NONE

1997-01-01

288

Sulfuric Acid on Europa's Surface and the Radiolytic Sulfur Cycle  

Microsoft Academic Search

Galileo infrared spectra of Europa's surface show distorted water bands that have been attributed to hydrated evaporite salts (McCord et al., J. Geophys. Res. 104, 11827, 1999) or to the scattering properties of ice (Dalton and Clark, Bull. Am. Astron. Soc. 30, 1081, 1998). Using new laboratory spectra, we show that hydrated sulfuric acid can explain Europa's spectra and further

R. W. Carlson; R. E. Johnson; M. S. Anderson

1999-01-01

289

Microbial stabilization of sulfur-laden sorbents. Technical report, March 1, 1994--May 31, 1994  

SciTech Connect

Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spent sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species requires additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide, sulfite, or various polythionate species serve as growth substrates for sulfur-oxidizing bacteria, which have the potential to convert all sulfur to sulfate. This quarter work continued with the solid phase of a spent slurry from an inhibited scrubber. The material was primarily CaSO{sub 3}{center_dot}1/2H{sub 2}O. The authors did not detect growth of any bacterial strain in salts medium with the solid phase as the source of sulfur. However, unlike strains of Thiobacillus neapolitanus, the isolate TQ, was not inhibited by the solid phase. Evidence suggests that this organism grows slowly on low concentrations of sulfite.

Miller, K.W.

1994-09-01

290

CE IGCC Repowering plant sulfuric acid plant. Topical report, June 1993  

SciTech Connect

A goal of the CE IGCC Repowering project is to demonstrate a hot gas clean-up system (HGCU), for the removal of sulfur from the product gas stream exiting the gasifier island. Combustion Engineering, Inc. (ABB CE) intends to use a HGCU developed by General Electric Environmental Services (GEESI). The original design of this system called for the installation of the HGCU, with a conventional cold gas clean-up system included as a full-load operational back-up. Each of these systems removes sulfur compounds and converts them into an acid off-gas. This report deals with the investigation of equipment to treat this off-gas, recovering these sulfur compounds as elemental sulfur, sulfuric acid or some other form. ABB CE contracted ABB Lummus Crest Inc. (ABB LCI) to perform an engineering evaluation to compare several such process options. This study concluded that the installation of a sulfuric acid plant represented the best option from both a technical and economic point of view. Based on this evaluation, ABB CE specified that a sulfuric acid plant be installed to remove sulfur from off-gas exiling the gas clean-up system. ABB LCI prepared a request for quotation (RFQ) for the construction of a sulfuric acid production plant. Monsanto Enviro-Chem Inc. presented the only proposal, and was eventually selected as the EPC contractor for this system.

Chester, A.M.

1993-12-01

291

The decomposition of methanol on the sulfur-modified Fe(100) surface  

NASA Astrophysics Data System (ADS)

Decomposition of methanol (CH 3OH) on sulfur-modified Fe(100) surfaces has been studied under ultrahigh vacuum (UHV) conditions, using temperature-programmed reaction spectroscopy (TPRS) and high-resolution electron energy loss spectroscopy (HREELS). Preadsorbed sulfur overlayers, prepared by thermal decomposition of CH 3SH, poison the decomposition of CH 3OH on the Fe(100) surface. The decomposition of methanol occurs by way of a methoxy (-OCH 3) intermediate on the sulfur-modified surface. The amount of methoxy intermediate formed in the decomposition process decreases as sulfur coverage increases. Preadsorbed sulfur atoms also modify the selectivity of the methanol decomposition. The formation of formaldehyde (H 2CO) is enhanced in a rather narrow sulfur coverage range, while the amount of carbon monoxide (CO) product decreases monotonically with increasing sulfur coverage. The effect of sulfur modification on the decomposition of methanol appears to be primarily a localized site blocking effect. Sulfur modification of the methanol decomposition on this surface is compared with that of the effect of oxygen modification.

Lu, J.-P.; Albert, M. R.; Bernasek, S. L.

1991-11-01

292

Commercial Alloys for Sulfuric Acid Vaporization in Thermochemical Hydrogen Cycles  

SciTech Connect

Most thermochemical cycles being considered for producing hydrogen include a processing stream in which dilute sulfuric acid is concentrated, vaporized and then decomposed over a catalyst. The sulfuric acid vaporizer is exposed to highly aggressive conditions. Liquid sulfuric acid will be present at a concentration of >96 wt% (>90 mol %) H2SO4 and temperatures exceeding 400oC [Brown, et. al, 2003]. The system will also be pressurized, 0.7-3.5 MPa, to keep the sulfuric acid in the liquid state at this temperature and acid concentration. These conditions far exceed those found in the commercial sulfuric acid generation, regeneration and handling industries. Exotic materials, e.g. ceramics, precious metals, clad materials, etc., have been proposed for this application [Wong, et. al., 2005]. However, development time, costs, reliability, safety concerns and/or certification issues plague such solutions and should be considered as relatively long-term, optimum solutions. A more cost-effective (and relatively near-term) solution would be to use commercially-available metallic alloys to demonstrate the cycle and study process variables. However, the corrosion behavior of commercial alloys in sulfuric acid is rarely characterized above the natural boiling point of concentrated sulfuric acid (~250oC at 1 atm). Therefore a screening study was undertaken to evaluate the suitability of various commercial alloys for concentration and vaporization of high-temperature sulfuric acid. Initially alloys were subjected to static corrosion tests in concentrated sulfuric acid (~95-97% H2SO4) at temperatures and exposure times up to 200oC and 480 hours, respectively. Alloys with a corrosion rate of less than 5 mm/year were then subjected to static corrosion tests at a pressure of 1.4 MPa and temperatures up to 375oC. Exposure times were shorter due to safety concerns and ranged from as short as 5 hours up to 144 hours. The materials evaluated included nickel-, iron- and cobalt-based commercial alloys. The corrosion rates in these tests are reported and how they may or may not relate to the corrosion behavior in an operating thermochemical cycle is discussed.

Thomas M. Lillo; Karen M. Delezene-Briggs

2005-10-01

293

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2013 CFR

... (c) A cargo space that contains sulfur or the residue of a sulfur cargo must be adequately ventilated, preferably by mechanical means. Each ventilator intake must be fitted with a spark-arresting...

2013-10-01

294

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2011 CFR

... (c) A cargo space that contains sulfur or the residue of a sulfur cargo must be adequately ventilated, preferably by mechanical means. Each ventilator intake must be fitted with a spark-arresting...

2011-10-01

295

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2014 CFR

... (c) A cargo space that contains sulfur or the residue of a sulfur cargo must be adequately ventilated, preferably by mechanical means. Each ventilator intake must be fitted with a spark-arresting...

2014-10-01

296

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2012 CFR

... (c) A cargo space that contains sulfur or the residue of a sulfur cargo must be adequately ventilated, preferably by mechanical means. Each ventilator intake must be fitted with a spark-arresting...

2012-10-01

297

Three-Zone Catalyst Resists Sulfur Poisoning  

NASA Technical Reports Server (NTRS)

Three-zone catalyst bed uses different types of nickel catalysts to convert sulfur-containing hydrocarbon fuels to hydrogen and carbon monoxide. Zones designed to achieve conversion with minimal residue of unconverted hydrocarbon, no soot and mimimal sulfur contamination.

Voecks, G. E.; Stephanopoulos, M. F.; Houseman, J.

1984-01-01

298

A global model of the coupled sulfur/oxidant chemistry in the troposphere: The sulfur cycle  

NASA Astrophysics Data System (ADS)

A sulfur cycle chemistry scheme with dimethyl sulfide (DMS), SO2, sulfate, H2S, and methanesulfonic acid (MSA) is included in the OsloCTM2 model, and concentrations of sulfur are calculated interactively with the oxidant chemistry. This allows more consistent estimates of aqueous phase oxidation of SO2 to sulfate by O3, H2O2, and HO2NO2. The year 1996 is chosen as the standard, and a model run with 1996 meteorology and emissions is compared with 1996 observations. The results agree well with observations overall, although the model tends to overestimate SO2 and underestimate sulfate in Northern Hemisphere winter owing to an oxidation limitation. A global budget for 1996 quantifying the various processes is investigated. Our model results give a global lifetime (global burden) of 1 day (0.25 Tg(S)) and 3.8 days (0.5 3 Tg(S)) for SO2 and sulfate. Differences between the Southern Hemisphere, characterized by natural emissions and by loss of SO2 by O3 and H2O2 oxidation, and the Northern Hemisphere, characterized by anthropogenic emissions and by large loss by dry deposition, are revealed. Significant changes in sulfur emissions have occurred over the last decades with decrease in the Unites States and Europe and increase in Southeast Asia. U.S., European, and Chinese SO2 emissions have changed by -17.6%, -47.5%, and +93%, respectively. To study the impact of emission changes on the atmospheric composition, we have calculated distributions using the Global Emissions Inventory Activity (GEIA) 1985 inventory. The changes in sulfur emissions have significant changes on the sulfur concentrations and also some effect upon the oxidants. Increased emissions of NOx and hydrocarbons in China enhance O3, but increased sulfur inhibit the increase. The SO2 oxidation by OH, which can lead to formation of new sulfate particles, is given special attention. The model run using GEIA 1985 anthropogenic emission inventory is compared with other model studies.

Berglen, Tore F.; Berntsen, Terje K.; Isaksen, Ivar S. A.; Sundet, Jostein K.

2004-10-01

299

Aqueous Mercury-Sulfur and Gold-Sulfur Complexes: An In-situ EXAFS Study  

NASA Astrophysics Data System (ADS)

Mineral and ore formation processes which involve mercury or gold often depend on aqueous speciation of these metals, and bioavailability of mercury is also affected by aqueous complexes. The nature of coordination by sulfur of these metals in aqueous solution is important for understanding the geochemical behaviour of these metals. The principal difficulty in using spectroscopy to study these heavy metal-sulfur complexes is that dissolved concentrations in sulfidic natural waters are very low. However, it is well known that Hg(II) is soluble in high sulfide concentrations and that Au(I) forms aqueous complexes with thiosulfate. Au(I) thiosulfate complexes have been proposed as sources of secondary enrichment of gold in supergene environments (Webster and Mann, 1984). We exploit these sulfur complexes to determine metal-sulfur bond distances and coordination numbers in aqueous solution. An internally heated titanium spectroscopic cell was designed for experiments on the high X-ray flux dynamic focussing EXAFS Station 16.5 at the Daresbury Synchrotron. Gold thiosulfate solutions (10 mM) were prepared from sodium bis(thiosulfate) aurate(I) dihydrate. Mercury sulfide solutions were prepared by dissolving metacinnabar in 50 mM Na2S solutions. X-ray fluorescence spectroscopic measurements were taken over the Au L(III)-edge at 11.918 keV and the Hg L(III)-edge at 12.284 keV to obtain the extended X-ray absorption fine structure (EXAFS) data. At room temperature, the best fit to EXAFS experimental data gives Au(I) coordinated by two S's at 2.30Å. No significant changes in Au-S distance are observed upon heating to 75° C. Above 100° C, the gold-thiosulfate complex decomposes. Au-S distances in the gold thiosulfate salt obtained from EXAFS are 2.28Å. Hg is also coordinated by 2 S's at 2.30Å at room temperature and at 75° C in the aqueous solution examined. These bond distances are shorter than Hg coordinated by 2 S's in cinnabar, 2.368Å, and much shorter than Hg coordinated by 4 S's in metacinnabar, 2.535Å [distances here from X-ray diffraction data]. These experimental results provide new data suitable for refining computational models of metal-sulfur complexes, and enhance our understanding of the aqueous sulfur geochemistry of mercury and gold. Reference: Webster JG and Mann AW (1984) The influence of climate, geomorphology and primary geology on the supergene migration of gold and silver. J. Geochem. Explor. 22, 21-42.

Lennie, A. R.; Pattrick, R. A.; Charnock, J. M.

2001-12-01

300

System for handling high sulfur materials  

Microsoft Academic Search

Sulfur oxides have a strong affinity for free lime and readily form gypsum anhydrite. By utilizing 2200°F or higher on-gas containing reduced quantities of sulfur to the preheat zone of a material treating apparatus, large quantities of sulfur can be removed from gases evolved in the rotary kiln. Utilizing lower sulfur content on-gas to preheat will substantially improve the ability

G. A. Heian; R. F. Kohl

1978-01-01

301

Involvement of Intermediate Sulfur Species in Biological Reduction of Elemental Sulfur under Acidic, Hydrothermal Conditions  

E-print Network

Involvement of Intermediate Sulfur Species in Biological Reduction of Elemental Sulfur under Acidic-Purdue University, Indianapolis, Indianapolis, Indiana, USAb The thermoacidophile and obligate elemental sulfur (S8-phase sulfur during S8 0 -dependent batch culture growth. Cyclic voltammetry indicated the production

Ahmad, Sajjad

302

Comparison of microbial sulfuric acid production in sewage sludge from added sulfur and thiosulfate  

Microsoft Academic Search

Microbial leaching is one of the most attractive methods of removing toxic metals from sewage sludge. Sulfuric acid produced by indigenous microflora by the oxidation of elemental sulfur and sulfur compounds solubilizes toxic metals. The oxidation of sulfur compounds can be achieved by the direct oxidation to sulfates or by indirect oxidation, through the production and accumulation of soluble intermediate

R. D. Tyagi; J. F. Blais; L. Deschenes; P. Lafrance; J. P. Villeneuve

1994-01-01

303

Origin of the {lambda} Transition in Liquid Sulfur  

SciTech Connect

Developing a novel experimental technique, we applied photon correlation spectroscopy using infrared radiation in liquid sulfur around T{sub {lambda}}, i.e., in the temperature range where an abrupt increase in viscosity by 4 orders of magnitude is observed upon heating within few degrees. This allowed us--overcoming photoinduced and absorption effects at visible wavelengths--to reveal a chain relaxation process with characteristic time in the millisecond range. These results do rehabilitate the validity of the Maxwell relation in sulfur from an apparent failure, allowing rationalizing of the mechanical and thermodynamic behavior of this system within a viscoelastic scenario.

Scopigno, T. [Research center SOFT-INFM-CNR, Universita di Roma 'La Sapienza', I-00185, Roma (Italy); Yannopoulos, S. N. [FORTH/ICE-HT, P.O. Box 141, GR-26504, Rio, Patras (Greece); Scarponi, F. [Dipartimento di Fisica, Universita di Perugia, via Pascoli, I-06123 Perugia (Italy); Andrikopoulos, K. S. [Physics Division, School of Technology, Aristotle University of Thessaloniki, GR-54124, Thessaloniki (Greece); Fioretto, D. [Dipartimento di Fisica, Universita di Perugia, via Pascoli, I-06123 Perugia (Italy); Research center SOFT-INFM-CNR, Universita di Roma 'La Sapienza', I-00185, Rome (Italy); Ruocco, G. [Dipartimento di Fisica, Universita di Roma 'La Sapienza', 00185 Rome (Italy); Research center SOFT-INFM-CNR, Universita di Roma 'La Sapienza', I-00185, Rome (Italy)

2007-07-13

304

Factors to consider for using zirconium in sulfuric acid services  

SciTech Connect

Zirconium is a pivotal material often specified for process equipment that handles highly corrosive sulfuric acid solutions. Because of the complicated nature of sulfuric acid, several factors should be addressed to ensure the durability of zirconium equipment. These factors include acid concentration, temperature, pressure, impurity, stress, crevices, welding, and surfaces condition. Depending on the situation, certain potential hazards to zirconium equipment can be prevented by applying control measures such as heat treatment, proper design and operating, inhibitor, surface conditioning and/or shot peening.

Fitzgerald, B.J. [Exxon Chemical Co., Baytown, TX (United States); Webber, R.G. [Exxon Chemical Co., Baton Rouge, LA (United States); Frechem, B.S. [Rohm and Haas Co., Spring House, PA (United States); Briegel, K.F. [Rohm and Haas Texas Co., Deer Park, TX (United States); Yau, T.L. [Teledyne Wah Chang, Albany, OR (United States)

1995-10-01

305

Sulfur isotope geochemistry of gypsiferous Aridisols from central Iran  

Microsoft Academic Search

Gypsum accumulation is one of the prominent pedogenic processes occurring in many and regions of the world. Gypsiferous soils occur in large areas of the Iranian central plateau. The origin of gypsum in the Aridisols of central Iran and its distribution in different landscapes were studied using sulfur and oxygen isotopic composition of both solid and dissolved sulfates. The results

H. Khademi; A. R. Mermut; H. R. Krouse

1997-01-01

306

The Hybrid Sulfur Cycle for Nuclear Hydrogen Production  

SciTech Connect

Two Sulfur-based cycles--the Sulfur-Iodine (SI) and the Hybrid Sulfur (HyS)--have emerged as the leading thermochemical water-splitting processes for producing hydrogen utilizing the heat from advanced nuclear reactors. Numerous international efforts have been underway for several years to develop the SI Cycle, but development of the HyS Cycle has lagged. The purpose of this paper is to discuss the background, current status, recent development results, and the future potential for this thermochemical process. Savannah River National Laboratory (SRNL) has been supported by the U.S. Department of Energy Office of Nuclear Energy, Science, and Technology since 2004 to evaluate and to conduct research and development for the HyS Cycle. Process design studies and flowsheet optimization have shown that an overall plant efficiency (based on nuclear heat converted to hydrogen product, higher heating value basis) of over 50% is possible with this cycle. Economic studies indicate that a nuclear hydrogen plant based on this process can be economically competitive, assuming that the key component, the sulfur dioxide-depolarized electrolyzer, can be successfully developed. SRNL has recently demonstrated the use of a proton-exchange-membrane electrochemical cell to perform this function, thus holding promise for economical and efficient hydrogen production.

Summers, William A.; Gorensek, Maximilian B.; Buckner, Melvin R.

2005-09-08

307

COAL GASIFICATION ENVIRONMENTAL DATA SUMMARY: SULFUR AND NITROGEN SPECIES  

EPA Science Inventory

The report summarizes data on sulfur and nitrogen species from the source test and environmental assessment studies of low- and medium-Btu gasification processes which were sponsored by the EPA between 1977 and 1981. The data are focused on the composition and distribution of the...

308

Hydrogen peroxide in sulfuric acid extraction of uranium ores  

SciTech Connect

Uranium can be extracted from its ores at a pH of 2.5 to 5.5 using sulfuric acid, hydrogen peroxide, trace of iron and a sulfate. The extraction process is applicable to both tank leaching of conventionally mined ores and in situ leaching.

DeVries, F.W.

1984-01-10

309

LIGNOSULFONATE-MODIFIED CALCIUM HYDROXIDE FOR SULFUR DIOXIDE CONTROL  

EPA Science Inventory

The article discusses the use of lignosulfonate-modified calcium hydroxide Ca(OH)2 for sulfur dioxide (SO2) control. The limestone injection multistage burner (LIMB) process is currently being developed at the U.S. EPA as a low cost retrofittable technology for controlling oxides...

310

Is development of high-grade gliomas sulfur-dependent?  

PubMed

We characterized ?-cystathionase, rhodanese and 3-mercaptopyruvate sulfurtransferase activities in various regions of human brain (the cortex, thalamus, hypothalamus, hippocampus, cerebellum and subcortical nuclei) and human gliomas with II to IV grade of malignancy (according to the WHO classification). The human brain regions, as compared to human liver, showed low ?-cystathionase activity. The activity of rhodanese was also much lower and it did not vary significantly between the investigated brain regions. The activity of 3-mercaptopyruvate sulfurtransferase was the highest in the thalamus, hypothalamus and subcortical nuclei and essentially the same level of sulfane sulfur was found in all the investigated brain regions. The investigations demonstrated that the level of sulfane sulfur in gliomas with the highest grades was high in comparison to various human brain regions, and was correlated with a decreased activity of ?-cystathionase, 3-mercaptopyruvate sulfurtransferase and rhodanese. This can suggest sulfane sulfur accumulation and points to its importance for malignant cell proliferation and tumor growth. In gliomas with the highest grades of malignancy, despite decreased levels of total free cysteine and total free glutathione, a high ratio of GSH/GSSG was maintained, which is important for the process of malignant cells proliferation. A high level of sulfane sulfur and high GSH/GSSG ratio could result in the elevated hydrogen sulfide levels. Because of the disappearance of ?-cystathionase activity in high-grade gliomas, it seems to be possible that 3-mercaptopyruvate sulfurtransferase could participate in hydrogen sulfide production. The results confirm sulfur dependence of malignant brain tumors. PMID:25532835

Wróbel, Maria; Czubak, Jerzy; Bronowicka-Adamska, Patrycja; Jurkowska, Halina; Adamek, Dariusz; Papla, Boles?aw

2014-01-01

311

Sulfur hexafluoride as a surrogate  

SciTech Connect

A viable chemical surrogate for monitoring the effectiveness of hazardous waste incinerators must include high thermal stability and low toxicity among its characteristics. The relationship between sulfur hexafluoride (SF6) and hazardous constituent thermal stability for a mixture of chlorinated hydrocarbons indicates that SF6 has the potential to satisfy the basic requirements of a chemical surrogate for hazardous waste incineration.

Taylor, P.H.; Chadbourne, J.F.

1987-06-01

312

Sulfur-tolerant anode materials  

NASA Astrophysics Data System (ADS)

Results of the second year's technical effort on a program to identify and evaluate alternative anode materials for use in molten carbonate fuel cells (MCFC) operating with high levels of sulfur contaminants in the fuel are summarized. In the first year of this program, a literature survey was performed covering all materials development research relating to electrode development for molten carbonate fuel cells. A final selection of 15 candidate materials was made, and samples of 9 of these 15 materials were fabricated and tested for electrical conductivity and for stability in the molten electrolyte. An additional 5 materials were evaluated during the second year. Several water-gas shift catalysts were also evaluated for their catalytic activity and sulfur resistance under conditions prevailing in the MCFC anode. These materials were titanium carbide, cobalt metal, copper metal, copper-nickel alloy, and lithium ferrate (III). Only the lithium ferrate (III) exhibited sulfur tolerance in that the performance of the lithium ferrate (III) cell did not change when sulfur was added to the fuel. The lithium ferrate (III) was then used to fabricate anodes for two 100 cm(2) bench-scale cells. These cells were assembled and operated on a medium-Btu simulated coal gasifier-derived fuel. Results are discussed.

Remick, Robert J.; Osif, Terry L.; Lawson, M. G.

1988-09-01

313

Nutrient cyling in soils: Sulfur  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sulfur (S) is an essential element required for normal plant growth, a fact that has been recognized since the nineteenth century. It is considered a secondary macronutrient, following the primary macronutrients nitrogen (N), phosphorus (P), and potassium (K), but is needed by plants at levels compa...

314

Seal for sodium sulfur battery  

DOEpatents

This invention is directed to a seal for a sodium sulfur battery in which the sealing is accomplished by a radial compression seal made on a ceramic component of the battery which separates an anode compartment from a cathode compartment of the battery.

Topouzian, Armenag (Birmingham, MI); Minck, Robert W. (Lathrup Village, MI); Williams, William J. (Northville, MI)

1980-01-01

315

Sodium--sulfur storage battery  

Microsoft Academic Search

This invention relates to a novel sodium--sulfur storage battery comprising a sodium reservoir made of metal (incorporating a heater) between double walls, a solid electrolyte connected to it, an anodic reactant contained in it and a cathode reactant outside of it, and a battery housing which contains the above-mentioned components. The battery is sealed at the upper part. According to

Kagawa

1977-01-01

316

SULFUR DIOXIDE SOURCES IN AK  

EPA Science Inventory

This map shows industrial plants which emit 100 tons/year or more of sulfur dioxide (SO2) in Alaska. The SO2 sources are plotted on a background map of cities and county boundaries. Data Sources: SO2 Sites: U.S. EPA AIRS System, County Outlines: 1990 Census Tiger Line Files 1:1...

317

A novel coal feeder for production of low sulfur fuel  

SciTech Connect

A novel coal feeding system is currently undergoing testing and evaluation at the University of Cincinnati. The system consists primarily of an auger feed tube which is used to both convey and provide desulfurization of a high sulfur coal feedstock. The coal is conveyed at temperatures ranging from 350 to 550 {degrees}C and under normal atmospheric pressure. Under these mild processing conditions, the coal partially pyrolizes and emits sulfur in the form of hydrogen sulfide while maintaining a relatively high heating value in the char product. The evolved gases are evacuated from the reactor (the feed tube) to another absorbing bed where H{sub 2}S reacts with the sorbent, usually lime or limestone. The resultant sorbent utilization is substantially higher than the values found in current dry scrubbing system and the produced low-sulfur char may then be used in a conventional steam boiler.

Keener, T.C.; Khang, S.J.; Yu, X.L.

1990-01-01

318

Dynamics of a Novel Class of Polymers: Polymerized Sulfur  

NASA Astrophysics Data System (ADS)

In this study we investigate the dynamics of a new type of polymer, consisting mainly of sulfur. Room-temperature stable polymerized sulfur samples were prepared by crosslinking the well-known living sulfur polymers formed at elevated temperatures by the addition of a crosslinking agent. This reverse vulcanization process was used to create a series of samples with different amounts of crosslinking agent. These polymers show great promise for use in advanced batteries as cathode materials. Each system exhibits a glassy-state beta relaxation, with the intensity of this relaxation proportional to the crosslinking content. A dynamic glass transition is also observed for each system, and the glass transition temperature/segmental relaxation moves to higher temperatures with increased crosslink content as is typically observed in crosslinked systems. As is typical of polymers, ion motion in these systems is closely coupled to the backbone motion of the host polymer.

Masser, Kevin; Kim, Jenny; Oleshko, Vladimir; Griebel, Jared; Chung, Woo; Simmons, Adam; Pyun, Jeff; Soles, Christopher

2013-03-01

319

Preliminary Investigation of Sulfur Loading in Hanford LAW Glass  

SciTech Connect

A preliminary estimate was developed for loading limits for high-sulfur low-activity waste (LAW) feeds that will be vitrified into borosilicate glass at the Hanford Site in the waste-cleanup effort. Previous studies reported in the literature were consulted to provide a basis for the estimate. The examination of previous studies led to questions about sulfur loading in Hanford LAW glass, and scoping tests were performed to help answer these questions. These results of these tests indicated that a formulation approach developed by Vienna and colleagues shows promise for maximizing LAW loading in glass. However, there is a clear need for follow-on work. The potential for significantly lowering the amount of LAW glass produced at Hanford (after the initial phase of processing) because of higher sulfur tolerances may outweigh the cost and effort required to perform the necessary testing.

Vienna, John D.; Hrma, Pavel R.; Buchmiller, William C.; Ricklefs, Joel S.

2004-04-01

320

Historical Sulfur Dioxide Emissions 1850-2000: Methods and Results  

SciTech Connect

A global, self-consistent estimate of sulfur dioxide emissions over the last one and a half century were estimated by using a combination of bottom-up and best available inventory methods including all anthropogenic sources. We find that global sulfur dioxide emissions peaked about 1980 and have generally declined since this time. Emissions were extrapolated to a 1{sup o} x 1{sup o} grid for the time period 1850-2000 at annual resolution with two emission height levels and by season. Emissions are somewhat higher in the recent past in this new work as compared with some comprehensive estimates. This difference is largely due to our use of emissions factors that vary with time to account for sulfur removals from fossil fuels and industrial smelting processes.

Smith, Steven J.; Andres, Robert; Conception , Elvira; Lurz, Joshua

2004-01-25

321

HYBRID SULFUR ELECTROLYZER DEVELOPMENT FY09 SECOND QUARTER REPORT  

SciTech Connect

The primary objective of the DOE-NE Nuclear Hydrogen Initiative (NHI) is to develop the nuclear hydrogen production technologies necessary to produce hydrogen at a cost competitive with other alternative transportation fuels. The focus of the NHI is on thermochemical cycles and high temperature electrolysis that can be powered by heat from high temperature gas reactors. The Savannah River National Laboratory (SRNL) has been tasked with the primary responsibility to perform research and development in order to characterize, evaluate and develop the Hybrid Sulfur (HyS) thermochemical process. This report documents work during the first quarter of Fiscal Year 2009, for the period between January 1, 2009 and March 31, 2009. The HyS Process is a two-step hybrid thermochemical cycle that is part of the 'Sulfur Family' of cycles. As a sulfur cycle, it uses high temperature thermal decomposition of sulfuric acid to produce oxygen and to regenerate the sulfur dioxide reactant. The second step of the process uses a sulfur dioxide depolarized electrolyzer (SDE) to split water and produce hydrogen by electrochemically reacting sulfur dioxide with H{sub 2}O. The SDE produces sulfuric acid, which is then sent to the acid decomposer to complete the cycle. The DOE NHI program is developing the acid decomposer at Sandia National Laboratory for application to both the HyS Process and the Sulfur Iodine Cycle. The SDE is being developed at SRNL. During FY05 and FY06, SRNL designed and conducted proof-of-concept testing for a SDE using a low temperature, PEM fuel cell-type design concept. The advantages of this design concept include high electrochemical efficiency, small footprint and potential for low capital cost, characteristics that are crucial for successful implementation on a commercial scale. During FY07, SRNL extended the range of testing of the SDE to higher temperature and pressure, conducted a 100-hour longevity test with a 60-cm{sup 2} single cell electrolyzer, and designed and built a larger, multi-cell stack electrolyzer. During FY08, SRNL continued SDE development, including development and successful testing of a three-cell electrolyzer stack with a rated capacity of 100 liters per hour. The HyS program for FY09 program will address improving SDE performance by focusing on preventing or minimizing sulfur deposition inside the cell caused by SO{sub 2} crossover, reduction of cell voltage for improved efficiency, an extension of cell operating lifetime. During FY09 a baseline technology development program is being conducted to address each of these issues. Button-cell (2-cm{sup 2}) and single cell (60-cm{sup 2}) SDEs will be fabricated and tested. A pressurized button-cell test facility will be designed and constructed to facilitate addition testing. The single cell test facility will be upgraded for unattended operation, and later for operation at higher temperature and pressure. Work will continue on development of the Gas Diffusion Electrode (GDE), or Gap Cell, as an alternative electrolyzer design approach that is being developed under subcontract with industry partner Giner Electrochemical Systems. If successful, it could provide an alternative means of preventing sulfur crossover through the proton exchange membrane, as well as the possibility for higher current density operation based on more rapid mass transfer in a gas-phase anode. Promising cell components will be assembled into membrane electrode assemblies (MEAs) and tested in the single cell test facility. Upon modification for unattended operation, test will be conducted for 200 hours or more. Both the button-cell and modified single cell facility will be utilized to demonstrate electrolyzer operation without sulfur build-up limitations, which is a Level 1 Milestone.

Herman, D; David Hobbs, D; Hector Colon-Mercado, H; Timothy Steeper, T; John Steimke, J; Mark Elvington, M

2009-04-15

322

VICARIOUS NUCLEOPHILIC SUBSTITUTION WITH SULFUR CONTAINING CARBANIONS  

Microsoft Academic Search

Carbanions stabilized with sulfur containing substituents are versatile intermedi-ates in organic synthesis. The great value and importance of such carbanions is connected with specific properties of the sulfur atom which is capable to exist in a variety of valent states and to form many functional groups. These various sulfur-containing groups exert different carbanion stabilizing effects and can also serve as

Mieczyslaw M?jkosza; Witold Danikiewicz; Krzysztof Wojciechowski

1990-01-01

323

8, 54135436, 2008 Ammonia in sulfuric  

E-print Network

ACPD 8, 5413­5436, 2008 Ammonia in sulfuric acid ion induced nucleation I. K. Ortega et al. Title.0 License. Atmospheric Chemistry and Physics Discussions The role of ammonia in sulfuric acid ion induced­5436, 2008 Ammonia in sulfuric acid ion induced nucleation I. K. Ortega et al. Title Page Abstract

Boyer, Edmond

324

Air Quality Criteria for Sulfur Oxides.  

ERIC Educational Resources Information Center

Included is a literature review which comprehensively discusses knowledge of the sulfur oxides commonly found in the atmosphere. The subject content is represented by the 10 chapter titles: Physical and Chemical Properties and the Atmospheric Reactions of the Oxides of Sulfur; Sources and Methods of Measurements of Sulfur Oxides in the Atmosphere;…

National Air Pollution Control Administration (DHEW), Washington, DC.

325

46 CFR 153.1046 - Sulfuric acid.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Sulfuric acid. 153.1046 Section 153...CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED...Procedures § 153.1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external tank...

2011-10-01

326

46 CFR 153.1046 - Sulfuric acid.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Sulfuric acid. 153.1046 Section 153...CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED...Procedures § 153.1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external tank...

2010-10-01

327

46 CFR 153.1046 - Sulfuric acid.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Sulfuric acid. 153.1046 Section 153...CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED...Procedures § 153.1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external tank...

2013-10-01

328

46 CFR 153.1046 - Sulfuric acid.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Sulfuric acid. 153.1046 Section 153...CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED...Procedures § 153.1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external tank...

2012-10-01

329

46 CFR 153.1046 - Sulfuric acid.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Sulfuric acid. 153.1046 Section 153...CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED...Procedures § 153.1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external tank...

2014-10-01

330

Spin chemical control of photoinduced electron-transfer processes in ruthenium(II)-trisbipyridine-based supramolecular triads: 2. The effect of oxygen, sulfur, and selenium as heteroatom in the azine donor.  

PubMed

Nanosecond time-resolved absorption studies in a magnetic field ranging from 0 to 2.0 T have been performed on a series of covalently linked donor(PXZ)-Ru(bipyridine)3-acceptor(diquat) complexes (D-C2+-A2+). In the PXZ moiety, the heteroatom (X = O (oxygen), T (sulfur), and S (selenium)) is systematically varied to study spin-orbit coupling effects. On the nanosecond time scale, the first detectable photoinduced electron-transfer product after exciting the chromophore C2+ is the charge-separated (CS) state, D+-C2+-A+, where an electron of the PXZ moiety, D, has been transferred to the diquat moiety, A2+. The magnetic-field-dependent kinetic behavior of charge recombination (monoexponential at 0 T progressing to biexponential for all three complexes with increasing field) can be quantitatively modeled by the radical pair relaxation mechanism assuming creation of the CS state with pure triplet spin correlation (3CS). Magnetic-field-independent contributions to the rate constant kr of T+/- --> (T0,S) relaxation are about 4.5 x 10(5) s-1 for DCA-POZ and -PTZ (due to a vibrational mechanism) and 3.5 x 10(6) s-1 for DCA-PSZ (due to spin rotational mechanism). Recombination to the singlet ground state is allowed only from the 1CS spin level; spin-forbidden recombination from 3CS seems negligible even for DCA-PSZ. The field dependence of kr (field-dependent recombination) can be decomposed into the contributions of various relaxation mechanisms. For all compounds, the electron spin dipolar coupling relaxation mechanism dominates the field dependence of tau(slow) at fields up to about 100 mT. Spin relaxation due to the g-tensor anisotropy relaxation mechanism accounts for the field dependence of tau(slow) for DCA-PSZ at high fields. For the underlying stochastic process, a very short correlation time of 2 ps has to be assumed, which is tentatively assigned to a flapping motion of the central, nonplanar ring in PSZ. Finally, it has been confirmed by paramagnetic quenching (here Heisenberg exchange) experiments of the magnetic-field effects with TEMPO that all magnetic-field dependencies observed with the present DCA-PSZ systems are indeed due to the magnetic-field dependence of spin relaxation. PMID:17432838

Rawls, Matthew T; Kollmannsberger, Georg; Elliott, C Michael; Steiner, Ulrich E

2007-05-10

331

High pressure sulfuric acid decomposition experiments for the sulfur-iodine thermochemical cycle.  

SciTech Connect

A series of three pressurized sulfuric acid decomposition tests were performed to (1) obtain data on the fraction of sulfuric acid catalytically converted to sulfur dioxide, oxygen, and water as a function of temperature and pressure, (2) demonstrate real-time measurements of acid conversion for use as process control, (3) obtain multiple measurements of conversion as a function of temperature within a single experiment, and (4) assess rapid quenching to minimize corrosion of metallic components by undecomposed acid. All four of these objectives were successfully accomplished. This report documents the completion of the NHI milestone on high pressure H{sub 2}SO{sub 4} decomposition tests for the Sulfur-Iodine (SI) thermochemical cycle project. All heated sections of the apparatus, (i.e. the boiler, decomposer, and condenser) were fabricated from Hastelloy C276. A ceramic acid injection tube and a ceramic-sheathed thermocouple were used to minimize corrosion of hot liquid acid on the boiler surfaces. Negligible fracturing of the platinum on zirconia catalyst was observed in the high temperature decomposer. Temperature measurements at the exit of the decomposer and at the entry of the condenser indicated that the hot acid vapors were rapidly quenched from about 400 C to less than 20 C within a 14 cm length of the flow path. Real-time gas flow rate measurements of the decomposition products provided a direct measurement of acid conversion. Pressure in the apparatus was preset by a pressure-relief valve that worked well at controlling the system pressure. However, these valves sometimes underwent abrupt transitions that resulted in rapidly varying gas flow rates with concomitant variations in the acid conversion fraction.

Velasquez, Carlos E; Reay, Andrew R.; Andazola, James C.; Naranjo, Gerald E.; Gelbard, Fred

2005-09-01

332

Rhodanese Functions as Sulfur Supplier for Key Enzymes in Sulfur Energy Metabolism  

PubMed Central

How microorganisms obtain energy is a challenging topic, and there have been numerous studies on the mechanisms involved. Here, we focus on the energy substrate traffic in the hyperthermophilic bacterium Aquifex aeolicus. This bacterium can use insoluble sulfur as an energy substrate and has an intricate sulfur energy metabolism involving several sulfur-reducing and -oxidizing supercomplexes and enzymes. We demonstrate that the cytoplasmic rhodanese SbdP participates in this sulfur energy metabolism. Rhodaneses are a widespread family of proteins known to transfer sulfur atoms. We show that SbdP has also some unusual characteristics compared with other rhodaneses; it can load a long sulfur chain, and it can interact with more than one partner. Its partners (sulfur reductase and sulfur oxygenase reductase) are key enzymes of the sulfur energy metabolism of A. aeolicus and share the capacity to use long sulfur chains as substrate. We demonstrate a positive effect of SbdP, once loaded with sulfur chains, on sulfur reductase activity, most likely by optimizing substrate uptake. Taken together, these results lead us to propose a physiological role for SbdP as a carrier and sulfur chain donor to these key enzymes, therefore enabling channeling of sulfur substrate in the cell as well as greater efficiency of the sulfur energy metabolism of A. aeolicus. PMID:22496367

Aussignargues, Clément; Giuliani, Marie-Cécile; Infossi, Pascale; Lojou, Elisabeth; Guiral, Marianne; Giudici-Orticoni, Marie-Thérèse; Ilbert, Marianne

2012-01-01

333

The removal of sulfur dioxide from flue gases  

PubMed Central

The growth of industrialization makes it imperative to reduce the amounts of sulfur dioxide emitted into the atmosphere. This article describes various processes for cleaning flue gases, and gives details of new methods being investigated. Wet scrubbing with water, though widely practised, has many disadvantages. Scrubbing with zinc oxide, feasible in zinc works, is more satisfactory. Dry methods use a solid absorbent; they have the advantage of a high emission temperature. Other methods are based on the addition to the fuel or the flue gases of substances such as activated metal oxides, which react with the sulfur to form compounds less harmful than sulfur dioxide. Also being investigated are a two-stage combustion system, in which the sulfur dioxide is removed in the first stage, and the injection of activated powdered dolomite into burning fuel; the resulting sulfates being removed by electrostatic precipitation. A wet catalysis process has recently been developed. Most of the cleaning processes are not yet technically mature, but first results show good efficiency and relatively low cost. PMID:14315714

Kettner, Helmut

1965-01-01

334

Determination of sulfur trioxide in engine exhaust.  

PubMed Central

Sulfur trioxide in the exhaust gas of an internal combustion engine is removed and concentrated by absorption in a solution of 80% isopropyl alcohol, which quantitatively absorbs it and inhibits the oxidation of any sulfur dioxide which may be absorbed. The absorbed sulfur trioxide (sulfuric acid) is determined by an absorption titration by using barium chloride as the titrant and thorin as the indicator. The sulfur dioxide content of the exhaust is measured continuously by means of a DuPont Model 411 ultraviolet photoanalyzer. PMID:50930

Arnold, D R

1975-01-01

335

CLOSEOUT REPORT FOR HYBRID SULFUR PRESSURIZED BUTTON CELL TEST FACILITY  

SciTech Connect

This document is the Close-Out Report for design and partial fabrication of the Pressurized Button Cell Test Facility at Savannah River National Laboratory (SRNL). This facility was planned to help develop the sulfur dioxide depolarized electrolyzer (SDE) that is a key component of the Hybrid Sulfur Cycle for generating hydrogen. The purpose of this report is to provide as much information as possible in case the decision is made to resume research. This report satisfies DOE Milestone M3GSR10VH030107.0. The HyS Cycle is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by watersplitting. The HyS Cycle utilizes the high temperature (>800 C) thermal decomposition of sulfuric acid to produce oxygen and regenerate sulfur dioxide. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Low cell voltage is essential for both high thermodynamic efficiency and low hydrogen cost. Sulfur dioxide is oxidized at the anode, producing sulfuric acid that is sent to the high temperature acid decomposition portion of the cycle. Sulfur dioxide from the decomposer is cycled back to electrolyzers. The electrolyzer cell uses the membrane electrode assembly (MEA) concept. Anode and cathode are formed by spraying a catalyst, typically platinized carbon, on both sides of a Proton Exchange Membrane (PEM). SRNL has been testing SDEs for several years including an atmospheric pressure Button Cell electrolyzer (2 cm{sup 2} active area) and an elevated temperature/pressure Single Cell electrolyzer (54.8 cm{sup 2} active area). SRNL tested 37 MEAs in the Single Cell electrolyzer facility from June 2005 until June 2009, when funding was discontinued. An important result of the final months of testing was the development of a method that prevents the formation of a sulfur layer previously observed in MEAs used in the Hybrid Sulfur Cycle electrolyzer. This result is very important because the sulfur layer increased cell voltage and eventually destroyed the MEA that is the heart of the cell. Steimke and Steeper [2005, 2006, 2007, 2008] reported on testing in the Single Cell Electrolyzer test facility in several periodic reports. Steimke et. al [2010] issued a final facility close-out report summarizing all the testing in the Single Cell Electrolyzer test facility. During early tests, significant deterioration of the membrane occurred in 10 hours or less; the latest tests ran for at least 200 hours with no sign of deterioration. Ironically, the success with the Single Cell electrolyzer meant that it became dedicated to long runs and not available for quick membrane evaluations. Early in this research period, the ambient pressure Button Cell Electrolyzer test facility was constructed to quickly evaluate membrane materials. Its small size allowed testing of newly developed membranes that typically were not available in sizes large enough to test in the Single Cell electrolyzer. The most promising membranes were tested in the Single Cell Electrolyzer as soon as sufficient large membranes could be obtained. However, since the concentration of SO{sub 2} gas in sulfuric acid decreases rapidly with increasing temperature, the ambient pressure Button Cell was no longer able to achieve the operating conditions needed to evaluate the newer improved high temperature membranes. Significantly higher pressure operation was required to force SO{sub 2} into the sulfuric acid to obtain meaningful concentrations at increased temperatures. A high pressure (200 psig), high temperature (120 C) Button Cell was designed and partially fabricated just before funding was discontinued in June 2009. SRNL completed the majority of the design of the test facility, including preparation of a process and instrument drawing (P&ID) and preliminary designs for the major components. SRNL intended to complete the designs and procu

Steeper, T.

2010-09-15

336

Electroanalytical chemistry of sulfur compounds for the new coal conversion technologies  

SciTech Connect

Polarographic methods are described tailor-made for the speciation and determination of sulfur contaminants in synfuels and coal gasification/liquefaction process streams. In samples containing the anions, S{sub x}{sup 2{minus}}, sulfidic sulfur was quantitated by anodic depolarization of the dropping mercury electrode, while polysulfidic sulfur was determined with the aid of an electroreduction process implicating 2(x-1) electrons. Polythionates were electroreduced to thiosulfate, sulfite, sulfide and/or mixtures thereof, under judiciously controlled experimental conditions. Thiosulfate and sulfite were quantitated by differential pulse polarography at dropping mercury anodes via reactions involving formation of thiosulfato- and sulfitomercurates. 14 refs., 2 figs.

Jordan, J. (Pennsylvania State Univ., University Park (USA)); Talbott, J. (Med-Chek Labs., Pittsburgh, PA (USA)); Yakupkovic, J. (Union Camp Corp., Princeton, NJ (USA))

1989-06-01

337

First-principles molecular dynamics simulations of (sulfuric acid)1(dimethylamine)1 cluster formation  

NASA Astrophysics Data System (ADS)

The clustering process (sulfuric acid) + (base)?(sulfuric acid)1(base)1 is of fundamental importance in the atmospheric new-particle formation. Especially interesting are the collisions where a proton transfer reaction can happen, as the reaction often leads to relatively strongly bound clusters. Here, we studied the clustering process of (sulfuric acid) + (dimethylamine) ? (sulfuric acid)1(dimethylamine)1 using first-principles molecular dynamics simulations. The collision of the two molecules was simulated starting with various spatial orientations and the evolution of the cluster was followed in the NVE ensemble. The simulations suggest that the proton transfer reaction takes place regardless of the intial collision orientation. However, due to the energy released in the process, the newly-formed cluster is not able to reach the minimun energy configuration, which might affect the following growth processes.

Loukonen, Ville; Bork, Nicolai; Vehkamäki, Hanna

2013-05-01

338

Task 4.4 - development of supercritical fluid extraction methods for the quantitation of sulfur forms in coal  

SciTech Connect

Development of advanced fuel forms depends on having reliable quantitative methods for their analysis. Determination of the true chemical forms of sulfur in coal is necessary to develop more effective methods to reduce sulfur content. Past work at the Energy & Environmental Research Center (EERC) indicates that sulfur chemistry has broad implications in combustion, gasification, pyrolysis, liquefaction, and coal-cleaning processes. Current analytical methods are inadequate for accurately measuring sulfur forms in coal. This task was concerned with developing methods to quantitate and identify major sulfur forms in coal based on direct measurement (as opposed to present techniques based on indirect measurement and difference values). The focus was on the forms that were least understood and for which the analytical methods have been the poorest, i.e., organic and elemental sulfur. Improved measurement techniques for sulfatic and pyritic sulfur also need to be developed. A secondary goal was to understand the interconversion of sulfur forms in coal during thermal processing. EERC has developed the first reliable analytical method for extracting and quantitating elemental sulfur from coal (1). This method has demonstrated that elemental sulfur can account for very little or as much as one-third of the so-called organic sulfur fraction. This method has disproved the generally accepted idea that elemental sulfur is associated with the organic fraction. A paper reporting the results obtained on this subject entitled {open_quote}Determination of Elemental Sulfur in Coal by Supercritical Fluid Extraction and Gas Chromatography with Atomic Emission Detection{close_quote} was published in Fuel (A).

Timpe, R.C.

1995-04-01

339

Advanced sulfur control concepts for hot gas desulfurization technology  

SciTech Connect

The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.

NONE

1998-09-01

340

Thermodynamic Properties of Sulfur Hexafluoride  

Microsoft Academic Search

We present new vapor phase speed-of-sound data u(P, T), new Burnett density–pressure–temperature data ?(P, T), and a few vapor pressure measurements for sulfur hexafluoride (SF6). The speed-of-sound data spanned the temperature range 230 K=T=460 K and reached maximum pressures that were the lesser of 1.5 MPa or 80% of the vapor pressure of SF6. The Burnett ?(P, T) data were obtained on isochores

J. J. Hurly; D. R. Defibaugh; M. R. Moldover

2000-01-01

341

Nutritional essentiality of sulfur in health and disease.  

PubMed

Sulfur is the seventh most abundant element measurable in the human body and is supplied mainly by the intake of methionine (Met), an indispensable amino acid found in plant and animal proteins. Met controls the initiation of protein synthesis, governs major metabolic and catalytic activities, and may undergo reversible redox processes safeguarding protein integrity. Withdrawal of Met from customary diets causes the greatest downsizing of lean body mass following either unachieved replenishment (malnutrition) or excessive losses (inflammation). These physiopathologically unrelated morbidities nevertheless stimulate comparable remethylation reactions from homocysteine, indicating that Met homeostasis benefits from high metabolic priority. Inhibition of cystathionine-?-synthase activity causes the upstream sequestration of homocysteine and the downstream drop in cysteine and glutathione. Consequently, the enzymatic production of hydrogen sulfide and the nonenzymatic reduction of elemental sulfur to hydrogen sulfide are impaired. Sulfur operates as cofactor of several enzymes critically involved in the regulation of oxidative processes. A combination of malnutrition and nutritional deprivation of sulfur maximizes the risk of cardiovascular disorders and stroke, constituting a novel clinical entity that threatens plant-eating population groups. PMID:23815141

Ingenbleek, Yves; Kimura, Hideo

2013-07-01

342

Geochemical and sulfur isotope signatures of microbial activity in acidic and sulfuric hot springs, northern Taiwan  

NASA Astrophysics Data System (ADS)

Acidic and sulfuric hot springs are natural habitats for thermophilic sulfur-utilizing microorganisms. Integration of bioenergetic evaluation, molecular analysis and stable isotopic signatures may be able to exhibit a full view of microbial activity in such an extreme environment. Widely distributed hot springs hosted by the Tatung volcano group in northern Taiwan provide a chance to evaluate the interplay between geochemical variation and microbial metabolism especially for sulfur. Several hot spring ponds varying in sizes and geochemical characteristics were studied to reveal the possible control of fluid compositions on microbial metabolisms, and vice versa. Sulfate, sulfide, elemental sulfur and dissolved organic carbon were available in spring water and sediments in the ponds. Dominant microbial metabolisms inferred from the bioenergetic evaluation were aerobic oxidations of various reduced compounds, including elemental sulfur, pyrite, ferrous iron and organic carbon. Sulfate and sulfur reductions were thermodynamically favorable but provided less energy flux, while sulfur disproportionation was thermodynamically incapable. The analyses of 16S rRNA genes extracted from the spring water and sediments indicated that aerobic oxidation of sulfur, hydrogen or organic carbon and anaerobic elemental sulfur reduction were possible metabolisms. Since the major portion of 16S rRNA sequences were affiliated with unclassified environmental sequences, their potential metabolisms remained obscure. Sulfur isotopic compositions of dissolved sulfate, pyrite and elemental sulfur exhibited significant variations among the different hot spring ponds. Apparently, the microbial effects on the sulfur isotopic signatures were various. A disproportionation reaction of volcanic gas was required to account for high sulfur isotope difference between sulfate and reduced sulfur in the large hot ponds. In contrary, abiotic or microbial oxidation of reduced sulfur might be dominant in the small ponds, where only small sulfur isotopic fractionation occurred among the sulfur species. Both sulfate and elemental sulfur reduction could not be recognized as the sulfide in all ponds were not the most depleted in S-34.

Wang, P.; Chen, K.; Cheng, T.; Hsieh, H.; Lin, L.

2009-12-01

343

Sulfur bacteria in wastewater stabilization ponds periodically affected by the 'red-water' phenomenon.  

PubMed

Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the 'red-water' phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El Menzeh WSP and focused in particular on the different functional groups of sulfur bacteria. For this purpose, we used denaturing gradient gel electrophoresis of PCR-amplified fragments of the 16S rRNA gene and of different functional genes involved in microbial sulfur metabolism (dsrB, aprA, and pufM). Analyses of the 16S rRNA revealed a relatively high microbial diversity where Proteobacteria, Chlorobi, Bacteroidetes, and Cyanobacteria constitute the major bacterial groups. The dsrB and aprA gene analysis revealed the presence of deltaproteobacterial sulfate-reducing bacteria (i.e., Desulfobacter and Desulfobulbus), while the analysis of 16S rRNA, aprA, and pufM genes assigned the sulfur-oxidizing bacteria community to the photosynthetic representatives belonging to the Chlorobi (green sulfur bacteria) and the Proteobacteria (purple sulfur and non sulfur bacteria) phyla. These results point on the diversity of the metabolic processes within this wastewater plant and/or the availability of sulfate and diverse electron donors. PMID:22354366

Belila, Abdelaziz; Abbas, Ben; Fazaa, Imed; Saidi, Neila; Snoussi, Mejdi; Hassen, Abdennaceur; Muyzer, Gerard

2013-01-01

344

The sulfur-fumigation reduces chemical composition and biological properties of Angelicae Sinensis Radix.  

PubMed

Angelica Sinensis Radix (roots of Angelica sinensis; ASR) is a popular herbal supplement in China for promoting blood circulation. Today, sulfur-fumigation is commonly used to treat ASR as a means of pest control; however, the studies of sulfur-fumigation on the safety and efficacy of ASR are very limited. Here, we elucidated the destructive roles of sulfur-fumigation on ASR by chemical and biological assessments. After sulfur-fumigation, the chemicals in ASR were significantly lost. The biological activities of anti-platelet aggregation, induction of NO production and estrogenic properties were compared between the water extracts of non-fumigated and sulfur-fumigated ASR. In all cases, the sulfur-fumigation significantly reduced the biological properties of ASR. In addition, application of water extract deriving from sulfur-fumigated ASR showed toxicity to cultured MCF-7 cells. In order to ensure the safety and to achieve the best therapeutic effect, it is recommended that sulfur-fumigation is an unacceptable approach for processing herbal materials. PMID:25172796

Zhan, Janis Ya-Xian; Yao, Ping; Bi, Cathy Wen-Chuan; Zheng, Ken Yu-Zhong; Zhang, Wendy Li; Chen, Jian-Ping; Dong, Tina Ting-Xia; Su, Zi-Ren; Tsim, Karl Wah-Keung

2014-09-25

345

Charge\\/discharge characteristics of sulfur composite cathode materials in rechargeable lithium batteries  

Microsoft Academic Search

The charge and discharge characteristics of lithium batteries with sulfur composite cathodes have been investigated. The sulfur composites showed novel electrochemical characteristics. The analysis of the differential capacity indicated that the discharge process showed two voltage plateaus of 2.10V and 1.88V, and the charge process also presented two voltage plateaus of 2.22V and 2.36V. The overcharge test showed that the

Xiangming He; Weihua Pu; Jianguo Ren; Li Wang; Jiulin Wang; Changyin Jiang; Chunrong Wan

2007-01-01

346

Development of Efficient Flowsheet and Transient Modeling for Nuclear Heat Coupled Sulfur Iodine Cyclefor Hydrogen Production  

SciTech Connect

The realization of the hydrogen as an energy carrier for future power sources relies on a practical method of producing hydrogen in large scale with no emission of green house gases. Hydrogen is an energy carrier which can be produced by a thermochemical water splitting process. The Sulfur-Iodine (SI) process is an example of a water splitting method using iodine and sulfur as recycling agents.

Shripad T. Revankar; Nicholas R. Brown; Cheikhou Kane; Seungmin Oh

2010-05-01

347

Sulfur cycling of intertidal Wadden Sea sediments (Konigshafen, Island of Sylt, Germany): sulfate reduction and sulfur gas emission  

NASA Astrophysics Data System (ADS)

Sulfate reduction rates (SRR t) and reduced inorganic sulfur pools (RIS) in Wadden Sea sediment as well as sulfur gas emissions directly to the atmosphere were measured at intervals of 2 to 12 months from 1991 to 1994. Three stations were chosen in the intertidal embayment, Königshafen, representing the range of sediments found in the Wadden Sea: Organic-poor coarse sand, organic-poor and Arenicola marina inhabited medium sand, and organic-rich muddy sand. Maximum SRR t were 2 to 5 times higher in muddy sand than in the sandy sediments. The depth-integrated SRR t varied 12 to 13-fold on a seasonal basis at the three stations. Although temperature controls biochemical processes, the overall control is more complex due to the simultaneous influence of other seasonal factors such as availability of organic matter and oxidation level of surface sediment. The sedimentary RIS pools were low due to iron limitation and contained only 30% acid volatile sulfur (AVS). Muddy sand had up to an order of magnitude more RIS than the two sandy sediments. The turnover of RIS was rapid (turnover time from ˜1 to 32 h), fastest during summer and at the sandy stations. The emission of S-gases was dominated by H 2S during summer (45-67% of the total), and was highest in muddy and lowest in coarse sand. H 2S was less important in early spring (3-49% of the total). Other sulfur gases, such as COS, DMS and CS 2, each accounted for less than 20% of the total sulfur emissions with no specific temporal and spatial pattern. Due to the low content of metals in the sediment, the reduced sulfur pools are cycled rapidly with chemical and biological reoxidation at oxic-anoxic boundaries as a major sink. Thus, the emissions of H 2S account for less than 1‰ of the sulfide produced.

Kristensen, E.; Bodenbender, J.; Jensen, M. H.; Rennenberg, H.; Jensen, K. M.

2000-05-01

348

Flash pyrolysis of coal, coal maceral, and coal-derived pyrite with on-line characterization of volatile sulfur compounds  

USGS Publications Warehouse

A Pyroprobe flash pyrolysis-gas chromatograph equipped with a flame photometric detector was used to study volatile sulfur compounds produced during the thermal decomposition of Illinois coal, coal macerals and coal-derived pyrite. Maximum evolution of volatile organic sulfur compounds from all coal samples occurred at a temperature of approximately 700??C. At this temperature, the evolution of thiophene, its alkyl isomers, and short-chain dialkyl sulfide compounds relative to the evolution of benzothiophene and dibenzothiophene compounds was greater from coal high in organic sulfur than from coal low in organic sulfur. The variation in the evolution of sulfur compounds observed for three separate coal macerals (exinite, vitrinite, and inertinite) was similar to that observed for whole coal samples. However, the variation trend for the macerals was much more pronounced. Decomposition of coal-derived pyrite with the evolution of elemental sulfur was detected at a temperature greater than 700??C. The results of this study indicated that the gas chromotographic profile of the volatile sulfur compounds produced during flash pyrolysis of coals and coal macerals varied as a function of the amount of organic sulfur that occurred in the samples. Characterization of these volatile sulfur compounds provides a better understanding of the behavior of sulfur in coal during the thermolysis process, which could be incorporated in the design for coal cleaning using flash pyrolysis techniques. ?? 1988.

Chou, I.-M.; Lake, M.A.; Griffin, R.A.

1988-01-01

349

Sulfur "Bergs" and Sulfur Pools: Loki and Tupan Patera on Io  

NASA Astrophysics Data System (ADS)

Loki and Tupan Patera on Io show numerous features related to the presence of volatiles. There are both striking similarities and distinct differences in the way the volatiles have acted at these two sites. At Loki numerous small bright features, colloquially known as sulfur "bergs", are distributed across the dark patera surface. We map their spatial distribution and spectral properties (Landis et al., this conference) and model sulfur vapor transport processes (Allen et al. this conference) to determine if those bright features are consistent with sulfur fumarole deposits. Alternatively, the "bergs" may represent topographic highs (kipukas) left un-resurfaced by the recurrent activity at Loki. To test this we examine Voyager, Galileo, and New Horizons images to determine if any changes in their spatial distribution have occurred over the 1979 through 2007 period. We also discuss further a statistical analysis of their size and spectral reflectance. Tupan shows an overall morphology similar to Loki, with a central island and one straight margin. It also shows linear features extending across the island. However instead of the dark eastern portion of the patera containing a myriad of small bright features like the Loki "bergs" which avoid the margins, Tupan shows higher albedo deposits concentrated at the margins. And in the higher albedo western portion of Tupan Patera numerous low albedo features can be interpreted as dark silicates erupting or eating through a volatile rich crust. Unlike Loki, these intra-patera features at Tupan clearly have sharply defined edges, indicating surface flow processes rather than possible vapor effects. However both outside the main Tupan Patera walls and on the island there are more diffuse patterns consistent with vapor transport. A detailed comparison of reflectance at violet through very near infrared wavelengths helps elucidate these effects. As also found at Loki, a low violet reflectance indicates that sulfur is abundant on many of the surfaces within the patera. That detailed comparison also helps highlight the vapor effects mentioned above. We discuss the insights into volatile processes gained from a detailed comparison of the Loki and Tupan images, and the implications those have for volcanism on Io.

Howell, R. R.; Lopes, R. M.; Landis, C. E.; Allen, D. R.

2012-12-01

350

Sulfur-infiltrated porous carbon microspheres with controllable multi-modal pore size distribution for high energy lithium-sulfur batteries  

NASA Astrophysics Data System (ADS)

Sulfur has received increasing attention as a cathode material for lithium-sulfur (Li-S) batteries due to its high theoretical specific capacity. However, the commercialization of Li-S batteries is limited by the challenges of poor electrical conductivity of sulfur, dissolution of the polysulfide intermediates into the electrolyte, and volume expansion of sulfur during cycling. Herein, we report the fabrication of novel-structured porous carbon microspheres with a controllable multi-modal pore size distribution, i.e., a combination of interconnected micropores, mesopores and macropores. Cathodes made of sulfur infiltrated in such a hierarchical carbon framework provide several advantages: (1) a continuous and high surface area carbon network for enhanced electrical conductivity and high sulfur loading; (2) macropores and large mesopores bridged by small mesopores to provide good electrolyte accessibility and fast Li ion transport and to accommodate volume expansion of sulfur; and (3) small mesopores and micropores to improve carbon/sulfur interaction and to help trap polysulfides. An initial discharge capacity at 1278 mA h g-1 and capacity retention at 70.7% (904 mA h g-1) after 100 cycles at a high rate (1 C) were achieved. The material fabrication process is relatively simple and easily scalable.Sulfur has received increasing attention as a cathode material for lithium-sulfur (Li-S) batteries due to its high theoretical specific capacity. However, the commercialization of Li-S batteries is limited by the challenges of poor electrical conductivity of sulfur, dissolution of the polysulfide intermediates into the electrolyte, and volume expansion of sulfur during cycling. Herein, we report the fabrication of novel-structured porous carbon microspheres with a controllable multi-modal pore size distribution, i.e., a combination of interconnected micropores, mesopores and macropores. Cathodes made of sulfur infiltrated in such a hierarchical carbon framework provide several advantages: (1) a continuous and high surface area carbon network for enhanced electrical conductivity and high sulfur loading; (2) macropores and large mesopores bridged by small mesopores to provide good electrolyte accessibility and fast Li ion transport and to accommodate volume expansion of sulfur; and (3) small mesopores and micropores to improve carbon/sulfur interaction and to help trap polysulfides. An initial discharge capacity at 1278 mA h g-1 and capacity retention at 70.7% (904 mA h g-1) after 100 cycles at a high rate (1 C) were achieved. The material fabrication process is relatively simple and easily scalable. Electronic supplementary information (ESI) available: Preparation process scheme; X-ray mapping images and EDX analysis for the surface of PMC/S-40; X-ray mapping images for the cross-section of PMC/S-40; thermogravimetric analysis (TGA) of PMC/S samples; T-plot results for PMC sample; and electrochemical measurements of lithium-sulfur batteries using PMC/S as cathode materials. See DOI: 10.1039/c3nr04532c

Zhao, Cunyu; Liu, Lianjun; Zhao, Huilei; Krall, Andy; Wen, Zhenhai; Chen, Junhong; Hurley, Patrick; Jiang, Junwei; Li, Ying

2013-12-01

351

Modified sulfur cement solidification of low-level wastes  

SciTech Connect

This topical report describes the results of an investigation on the solidification of low-level radioactive wastes in modified sulfur cement. The work was performed as part of the Waste Form Evaluation Program, sponsored by the US Department of Energy's Low-Level Waste Management Program. Modified sulfur cement is a thermoplastic material developed by the US Bureau of Mines. Processing of waste and binder was accomplished by means of both a single-screw extruder and a dual-action mixing vessel. Waste types selected for this study included those resulting from advanced volume reduction technologies (dry evaporator concentrate salts and incinerator ash) and those which remain problematic for solidification using contemporary agents (ion exchange resins). Process development studies were conducted to ascertain optimal process control parameters for successful solidification. Maximum waste loadings were determined for each waste type and method of processing. Property evaluation testing was carried out on laboratory scale specimens in order to compare with waste form performance for other potential matrix materials. Waste form property testing included compressive strength, water immersion, thermal cycling and radionuclide leachability. Recommended waste loadings of 40 wt. % sodium sulfate and boric acid salts and 43 wt. % incinerator ash, which are based on processing and performance considerations, are reported. Solidification efficiencies for these waste types represent significant improvements over those of hydraulic cements. Due to poor waste form performance, incorporation of ion exchange resin waste in modified sulfur cement is not recommended.

Not Available

1985-10-01

352

A combined proteomic and transcriptomic analysis on sulfur metabolism pathways of Arabidopsis thaliana under simulated acid rain.  

PubMed

With rapid economic development, most regions in southern China have suffered acid rain (AR) pollution. In our study, we analyzed the changes in sulfur metabolism in Arabidopsis under simulated AR stress which provide one of the first case studies, in which the systematic responses in sulfur metabolism were characterized by high-throughput methods at different levels including proteomic, genomic and physiological approaches. Generally, we found that all of the processes related to sulfur metabolism responded to AR stress, including sulfur uptake, activation and also synthesis of sulfur-containing amino acid and other secondary metabolites. Finally, we provided a catalogue of the detected sulfur metabolic changes and reconstructed the coordinating network of their mutual influences. This study can help us to understand the mechanisms of plants to adapt to AR stress. PMID:24595051

Liu, Tingwu; Chen, Juan A; Wang, Wenhua; Simon, Martin; Wu, Feihua; Hu, Wenjun; Chen, Juan B; Zheng, Hailei

2014-01-01

353

Optical properties of sulfur copolymers for infrared applications  

NASA Astrophysics Data System (ADS)

The development of organic polymers with high refractive indices has been widely investigated, as a possible alternative to inorganic metal oxide, semiconductor, or chalcogenide-based materials for a variety of optical devices and components, such as waveguides, anti-reflective coatings, charge-coupled devices and fiber optic cables. In principle, organic-based polymers are attractive for these applications because of their low weight, ease of processing, mechanical toughness, and facile chemical variation using commercially available precursors. However, one of the fundamental challenges associated with organic polymers is their generally low refractive indices in comparison to their inorganic counterparts. Herein we report on the optical characterization of a new class of sulfur copolymers that are readily moldable, transparent above 500nm, possess high refractive index (n < 1.8) and take advantage of the low infrared absorption of S?S bonds for potential use in the mid-infrared at 3-5 microns. These materials are largely made from elemental sulfur by an inverse vulcanization process; in the current study we focus on the properties of a chemically stable, branched copolymer of poly(sulfur-random-1,3-diisopropenylbenzene) (poly(S-r-DIB). Copolymers with elemental sulfur content ranging from 50% to 80% by weight were studied by UV-VIS spectroscopy, FTIR, and prism coupling for refractive index measurement. Clear correlation between material composition and the optical properties was established, confirming that the high polarizability of the sulfur atom leads to high refractive index while also maintaining low optical loss. Applications of the materials for bulk optics, high-density photonic circuits, and infrared components will also be discussed.

Namnabat, Soha; Gabriel, Jared J.; Pyun, Jeffrey; Norwood, Robert A.

2014-03-01

354

Ceramic-metal seals for advanced battery systems. [sodium sulfur and lithium sulfur batteries  

NASA Technical Reports Server (NTRS)

The search for materials which are electrochemically compatible with the lithium sulfur and sodium sulfur systems is discussed. The use liquid or braze alloys, titanium hydrite coatings, and tungsten yttria for bonding beryllium with ceramic is examined.

Reed, L.

1978-01-01

355

The use of sulfur in dermatology.  

PubMed

Sulfur has antifungal, antibacterial, and keratolytic activity. In the past, its use was widespread in dermatological disorders such as acne vulgaris, rosacea, seborrheic dermatitis, dandruff, pityriasis versicolor, scabies, and warts. Adverse events associated with topically applied sulfur are rare and mainly involve mild application site reactions. Sulfur, used alone or in combination with agents such as sodium sulfacetamide or salicylic acid, has demonstrated efficacy in the treatment of many dermatological conditions. PMID:15303787

Gupta, Aditya K; Nicol, Karyn

2004-01-01

356

HYDROCARBON AND SULFUR SENSORS FOR SOFC SYSTEMS  

SciTech Connect

The following report summarizes work conducted during the Phase I program Hydrocarbon and Sulfur Sensors for SOFC Systems under contract No. DE-FC26-02NT41576. For the SOFC application, sensors are required to monitor hydrocarbons and sulfur in order to increase the operation life of SOFC components. This report discusses the development of two such sensors, one based on thick film approach for sulfur monitoring and the second galvanic based for hydrocarbon monitoring.

A.M. Azad; Chris Holt; Todd Lesousky; Scott Swartz

2003-11-01

357

Sulfur Chemistry in Bacterial Leaching of Pyrite  

Microsoft Academic Search

In the case of pyrite bioleaching byLeptospirillum ferrooxidans, an organism without sulfur-oxidizing capac- ity, besides the production of tetra- and pentathionate, a considerable accumulation of elemental sulfur occurred. A similar result was obtained for chemical oxidation assays with acidic, sterile iron(III) ion- containing solutions. In the case of Thiobacillus ferrooxidans, only slight amounts of elemental sulfur were detectablebecauseoftheorganism'scapacitytooxidizesulfurcompounds.Inthecourseofoxidative,chemical pyrite degradation

AXEL SCHIPPERS; PETER-GEORG JOZSA

1996-01-01

358

The Solar Flare Sulfur Abundance from RESIK Observations  

NASA Astrophysics Data System (ADS)

The RESIK instrument on CORONAS-F spacecraft observed several sulfur X-ray lines in three of its four channels covering the wavelength range 3.8-6.1 Å during solar flares. The fluxes are analyzed to give the sulfur abundance. Data are chosen for when the instrument parameters were optimized. The measured fluxes of the S XV 1s 2-1s4p (w4) line at 4.089 Å gives A(S) = 7.16 ± 0.17 (abundances on a logarithmic scale with A(H) = 12) which we consider to be the most reliable. Estimates from other lines range from 7.13 to 7.24. The preferred S abundance estimate is very close to recent photospheric abundance estimates and to quiet-Sun solar wind and meteoritic abundances. This implies no fractionation of sulfur by processes tending to enhance the coronal abundance from the photospheric that depend on the first ionization potential (FIP), or that sulfur, though its FIP has an intermediate value of 10.36 eV, acts like a "high-FIP" element.

Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kuznetsov, V. D.

2012-06-01

359

THE SOLAR FLARE SULFUR ABUNDANCE FROM RESIK OBSERVATIONS  

SciTech Connect

The RESIK instrument on CORONAS-F spacecraft observed several sulfur X-ray lines in three of its four channels covering the wavelength range 3.8-6.1 A during solar flares. The fluxes are analyzed to give the sulfur abundance. Data are chosen for when the instrument parameters were optimized. The measured fluxes of the S XV 1s{sup 2}-1s4p (w4) line at 4.089 A gives A(S) = 7.16 {+-} 0.17 (abundances on a logarithmic scale with A(H) = 12) which we consider to be the most reliable. Estimates from other lines range from 7.13 to 7.24. The preferred S abundance estimate is very close to recent photospheric abundance estimates and to quiet-Sun solar wind and meteoritic abundances. This implies no fractionation of sulfur by processes tending to enhance the coronal abundance from the photospheric that depend on the first ionization potential (FIP), or that sulfur, though its FIP has an intermediate value of 10.36 eV, acts like a 'high-FIP' element.

Sylwester, J.; Sylwester, B. [Space Research Centre, Polish Academy of Sciences, 51-622, Kopernika 11, Wroclaw (Poland); Phillips, K. J. H. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Kuznetsov, V. D., E-mail: js@cbk.pan.wroc.pl, E-mail: bs@cbk.pan.wroc.pl, E-mail: kjhp@mssl.ucl.ac.uk, E-mail: kvd@izmiran.ru [Institute of Terrestrial Magnetism and Radiowave Propagation (IZMIRAN), Troitsk, Moscow (Russian Federation)

2012-06-01

360

Energy and environmental research emphasizing low-rank coal--Task 4.4: Development of supercritical fluid extraction methods for the quantitation of sulfur forms in coal  

SciTech Connect

Current analytical methods are inadequate for accurately measuring sulfur forms in coal. This task was concerned with developing methods to quantitate and identify major sulfur forms in coal based on direct measurement (as opposed to present techniques based on indirect measurement and difference values). The focus was on the forms that were least understood and for which the analytical methods have been the poorest, i.e., organic and elemental sulfur. Improved measurement techniques for sulfatic and pyritic sulfur also need to be developed. A secondary goal was to understand the interconversion of sulfur forms in coal during thermal processing. This task had as its focus the development of selective extraction methods that will allow the direct measurement of sulfur content in each form. Therefore, selective extraction methods were needed for the major sulfur forms in coal, including elemental, pyritic, sulfatic, and organic sulfur. This study was a continuation of that of previous analytical method development for sulfur forms in coal which resulted in the successful isolation and quantitation of elemental and sulfatic sulfur. Super- and subcritical extractions with methanol or water with and without additives were investigated in an attempt to develop methods for pyritic and organic sulfur forms analysis in coal. Based on these studies, a sequential extraction scheme that is capable of selectively determining elemental, sulfatic, pyritic and two forms of organic sulfur is presented here.

Timpe, R.C.

1995-04-01

361

Are the clouds of Venus sulfuric acid.  

NASA Technical Reports Server (NTRS)

It is shown that strong aqueous sulfuric acid solutions have the right refractive index and freeze at Venusian cloud temperature, explain the dryness of the Venusian stratosphere, are consistent with some features of the Venusian IR spectrum, and do not absorb in highly reflecting areas of Venus. It is also indicated that such solutions should be produced by reactions between known atmospheric constituents and most sulfur-bearing rock at the Venusian surface temperature, and require only small amounts of sulfur consistent with its cosmic abundance and with the amounts of other volatile elements present in the atmosphere. It is believed therefore that the clouds of Venus consist of sulfuric acid solutions.

Young, A. T.

1973-01-01

362

Prediction Model of Sulfur Deposition in the High Sulfur Gas Well Bore  

Microsoft Academic Search

Sulfur deposition in the well bore not only jams the equipment and pipeline, but also gets heavy corrosion of down-hole’s\\u000a pipe string and rig on ground. The accurate prediction of sulfur deposition in the well bore is very important. Because sulfur\\u000a solubility is a function of temperature and pressure in the high sulfur gas well bore, this paper addressed solubility

Chun-bi Xu; Jiong Wang; Shun-peng Zeng

363

Sulfuric Acid Production on Europa: The Radiolysis of Sulfur in Water Ice  

Microsoft Academic Search

Europa's surface is chemically altered by radiolysis from energetic charged particle bombardment. It has been suggested that hydrated sulfuric acid (H2SO4·nH2O) is a major surface species and is part of a radiolytic sulfur cycle, where a dynamic equilibrium exists between continuous production and destruction of sulfur polymers Sx, sulfur dioxide SO2, hydrogen sulfide H2S, and H2SO4·nH2O. We measured the rate

R. W. Carlson; M. S. Anderson; R. E. Johnson; M. B. Schulman; A. H. Yavrouian

2002-01-01

364

Sulfuric Acid Production on Europa: The Radiolysis of Sulfur in Water Ice  

Microsoft Academic Search

Europa's surface is chemically altered by radiolysis from energetic charged particle bombardment. It has been suggested that hydrated sulfuric acid (H2SO4.nH2O) is a major surface species and is part of a radiolytic sulfur cycle, where a dynamic equilibrium exists between continuous production and destruction of sulfur polymers Sx, sulfur dioxide SO2, hydrogen sulfide H2S, and H2SO4.nH2O. We measured the rate

R. W. Carlson; M. S. Anderson; R. E. Johnson; M. B. Schulman; A. H. Yavrouian

2002-01-01

365

Heat Transfer Characteristics of Sulfur and Sulfur Diluted with Hydrogen Sulfide Flowing Through Circular Tubes  

E-print Network

diluted with H2S, added as persulfide. Viscosity of sulfur diluted with H2S, added as liquid. . . 50 51 Viscosity of liquid sulfur 52 Characteristics of sulfur-density and thermal conductivity. . . . 53 Heat capacity of sulfur 54 Characteristics... from a reactor. It has a high heat capacity and excellent heat transfer characteris- tics, and does not require special corrosion-resistant system components. Its nuclear properties are also favorable. It is not subject to destructive or hazardous...

Stone, Porter Walwyn

2012-06-07

366

Multiple sulfur isotope constraints on the modern sulfur cycle  

NASA Astrophysics Data System (ADS)

We present 28 multiple sulfur isotope measurements of seawater sulfate (?34S and ?33S) from the modern ocean over a range of water depths and sites along the eastern margin of the Pacific Ocean. The average measured ?34S is 21.24‰ (±0.88‰,2?) with a calculated ?33S of +0.050‰ (±0.014‰,2?). With these values, we use a box-model to place constraints on the gross fraction of pyrite burial in modern sediments. This model presents an improvement on previous estimates of the global pyrite burial flux because it does not rely on the assumed value of ?34S, which is poorly constrained, but instead uses new information about the relationship between ?34S and ?33S in global marine sulfate. Our calculations indicate that the pyrite burial flux from the modern ocean is between 10% and 45% of the total sulfur lost from the oceans, with a more probable range between 20% and 35%.

Tostevin, Rosalie; Turchyn, Alexandra V.; Farquhar, James; Johnston, David T.; Eldridge, Daniel L.; Bishop, James K. B.; McIlvin, Matthew

2014-06-01

367

Coexistence Curve of Sulfur Hexafluoride  

Microsoft Academic Search

The coexistence curve of sulfur hexafluoride has been determined by interferometric measurements for the temperature range 10-5<(Tc-T)Tc<10-1. The refractive index difference nl-nv is fitted by a power law. The difference Deltan is proportional to (DeltaT)beta, where beta=0.346+\\/-0.001 for the temperature range 10-2<(Tc-T)Tc<10-1. The exponent beta decreases to 0.339 +\\/- 0.003 as (Tc-T)Tc decreases to the lower limit of the data

D. Balzarini; K. Ohrn

1972-01-01

368

Catalytic oxidation of sulfur dioxide  

SciTech Connect

A review of the vanadium-catalyzed sulfur dioxide oxidation at 400/sup 0/C (ignition point) to 620/sup 0/C (thermal deactivation point) and 6-12% initial SO/sub 2/ concentration covers the vanadium catalyst composition and properties; the reaction mechanism; 29 kinetic equations, their range of applicability, and their inadequacy as general rate equations; intraparticle mass and heat transfer studies; experimental methods for determining the global reaction rate; and reactor design, including mathematical modeling and optimization of adiabatic, nonadiabatic, and nonideal adiabatic beds.

Urbanek, A. (Warsaw Tech. Univ.); Trela, M.

1980-01-01

369

Economic comparison of hydrogen production using sulfuric acid electrolysis and sulfur cycle water decomposition. Final report  

Microsoft Academic Search

An evaluation of the relative economics of hydrogen production using two advanced techniques was performed. The hydrogen production systems considered were the Westinghouse Sulfur Cycle Water Decomposition System and a water electrolysis system employing a sulfuric acid electrolyte. The former is a hybrid system in which hydrogen is produced in an electrolyzer which uses sulfur dioxide to depolarize the anode.

G. H. Farbman; B. R. Krasicki; C. C. Hardman; S. S. Lin; G. H. Parker

1978-01-01

370

Binding mechanism of sulfur and dehydrogenated polyacrylonitrile in sulfur/polymer composite cathode  

NASA Astrophysics Data System (ADS)

A composite consisting of sulfur/dehydrogenated polyacrylonitrile is one of the most promising cathode materials for use in rechargeable lithium-sulfur batteries. However, the reported sulfur contents have been low, less than 50 wt%, which compromise the intrinsic high specific capacity and energy of elemental sulfur and hence decrease significantly the specific energy of the composite. To identify the potential to further increase the sulfur content, we elucidate the binding mechanism of sulfur and polyacrylonitrile in their composite. The heat treatment experiments at varying timespans with excess sulfur showed a constancy of sulfur content after a critical length of timespan, indicating the saturation of sulfur in the structure of dehydrogenated polyacrylonitrile. Based on molecular structure and size consideration, it is proposed that the binding involves the formation of an 8 membered ring of sulfur embedded between 4 heterocyclic rings of dehydrogenated polyacrylonitrile. From this model and experimental results, we show that there exists an upper limit of sulfur content in the sulfur/dehydrogenated polyacrylonitrile composite at 56 wt%.

Doan, The Nam Long; Ghaznavi, Mahmoudreza; Zhao, Yan; Zhang, Yongguang; Konarov, Aishuak; Sadhu, Mikhail; Tangirala, Ravichandra; Chen, P.

2013-11-01

371

ECONOMICS OF NITROGEN OXIDES, SULFUR OXIDES, AND ASH CONTROL SYSTEMS FOR COAL-FIRED UTILITY POWER PLANTS  

EPA Science Inventory

The report gives results of an EPA-sponsored economic evaluation of three processes to reduce NOx, SO2, and ash emissions from coal-fired utility power plants: one based on 3.5% sulfur eastern bituminous coal; and the other, on 0.7% sulfur western subbituminous coal. NOx control ...

372

Selective catalytic reduction of sulfur dioxide to elemental sulfur. Final report  

SciTech Connect

This project has investigated new metal oxide catalysts for the single stage selective reduction of SO{sub 2} to elemental sulfur by a reductant, such as CO. Significant progress in catalyst development has been made during the course of the project. We have found that fluorite oxides, CeO{sub 2} and ZrO{sub 2}, and rare earth zirconates such as Gd{sub 2}Zr{sub 2}O{sub 7} are active and stable catalysts for reduction Of SO{sub 2} by CO. More than 95% sulfur yield was achieved at reaction temperatures about 450{degrees}C or higher with the feed gas of stoichiometric composition. Reaction of SO{sub 2} and CO over these catalysts demonstrated a strong correlation of catalytic activity with the catalyst oxygen mobility. Furthermore, the catalytic activity and resistance to H{sub 2}O and CO{sub 2} poisoning of these catalysts were significantly enhanced by adding small amounts of transition metals, such as Co, Ni, Co, etc. The resulting transition metal-fluorite oxide composite catalyst has superior activity and stability, and shows promise in long use for the development of a greatly simplified single-step sulfur recovery process to treat variable and dilute SO{sub 2} concentration gas streams. Among various active composite catalyst systems the Cu-CeO{sub 2} system has been extensively studied. XRD, XPS, and STEM analyses of the used Cu-CeO{sub 2} catalyst found that the fluorite crystal structure of ceria was stable at the present reaction conditions, small amounts of copper was dispersed and stabilized on the ceria matrix, and excess copper oxide particles formed copper sulfide crystals of little contribution to catalytic activity. A working catalyst consisted of partially sulfated cerium oxide surface and partially sulfided copper clusters. The overall reaction kinetics were approximately represented by a first order equation.

Liu, W.; Flytzani-Stephanopoulos, M.; Sarofim, A.F.

1995-06-01

373

Graphene-wrapped sulfur nanospheres with ultra-high sulfur loading for high energy density lithium-sulfur batteries  

NASA Astrophysics Data System (ADS)

Lithium-sulfur (Li-S) battery with high theoretical energy density is one of the most promising energy storage systems for electric vehicles and intermittent renewable energy. However, due to the poor conductivity of the active material, considerable weight of the electrode is occupied by the conductive additives. Here we report a graphene-wrapped sulfur nanospheres composite (S-nanosphere@G) with sulfur content up to 91 wt% as the high energy density cathode material for Li-S battery. The sulfur nanospheres with diameter of 400-500 nm are synthesized through a solution-based approach with the existence of polyvinylpyrrolidone (PVP). Then the sulfur nanospheres are uniformly wrapped by conductive graphene sheets through the electrostatic interaction between graphene oxide and PVP, followed by reducing of graphene oxide with hydrazine. The design of graphene wrapped sulfur nanoarchitecture provides flexible conductive graphene coating with void space to accommodate the volume expansion of sulfur and to minimize polysulfide dissolution. As a result, the S-nanosphere@G nanocomposite with 91 wt% sulfur shows a reversible initial capacity of 970 mA h g-1 and an average columbic efficiency > 96% over 100 cycles at a rate of 0.2 C. Taking the total mass of electrode into account, the S-nanosphere@G composite is a promising cathode material for high energy density Li-S batteries.

Liu, Ya; Guo, Jinxin; Zhang, Jun; Su, Qingmei; Du, Gaohui

2015-01-01

374

NONEQUILIBRIUM SULFUR CAPTURE & RETENTION IN AN AIR COOLED SLAGGING COAL COMBUSTOR  

SciTech Connect

Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. The reacted particles impact and melt in the liquid slag layer on the combustor wall by the centrifugal force of the swirling combustion gases. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Prior analyses and laboratory scale data indicated that for Coal Tech's 20 MMBtu/hour, air-cooled, slagging coal combustor slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to validate this sulfur-in-slag model in a group of combustor tests. A total of 36 days of testing on the combustor were completed during the period of performance of this project. This was more that double the 16 test days that were required in the original work statement. The extra tests were made possible by cost saving innovations that were made in the operation of the combustor test facility and in additional investment of Coal Tech resources in the test effort. The original project plan called for two groups of tests. The first group of tests involved the injection of calcium sulfate particles in the form of gypsum or plaster of Paris with the coal into the 20 MMBtu/hour-combustor. The second group of tests consisted of the entire two-step process, in which lime or limestone is co-injected with coal and reacts with the sulfur gas released during combustion to form calcium sulfate particles that impact and dissolve in the slag layer. Since this sulfur capture process has been validated in numerous prior tests in this combustor, the primary effort in the present project was on achieving the high slag flow rates needed to retain the sulfur in the slag.

Bert Zauderer

2003-04-21

375

Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io  

NASA Technical Reports Server (NTRS)

Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deepsea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earth's early evolutionary period.

Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

2001-01-01

376

Atmospheric sulfur hexafluoride: Sources, sinks and greenhouse warming  

Microsoft Academic Search

Model calculations using estimated reaction rates of sulfur hexafluoride (SF6) with OH and O(1D) indicate that the atmospheric lifetime due to these processes may be very long (25,000 years). An upper limit for the UV cross section would suggest a photolysis lifetime much longer than 1000 years. The possibility of other removal mechanisms are discussed. The estimated lifetimes are consistent

Malcolm K. W. Ko; Nien Dak Sze; Wei-Chyung Wang; George Shia; Aaron Goldman; Frank J. Murcray; David G. Murcray; Curtis P. Rinsland

1993-01-01

377

40 CFR 52.231 - Regulations: Sulfur oxides.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Regulations: Sulfur oxides. 52.231 Section 52.231 Protection...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved] (b...Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate...

2013-07-01

378

40 CFR 52.231 - Regulations: Sulfur oxides.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Regulations: Sulfur oxides. 52.231 Section 52.231 Protection...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved] (b...Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate...

2012-07-01

379

40 CFR 52.231 - Regulations: Sulfur oxides.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Regulations: Sulfur oxides. 52.231 Section 52.231 Protection...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved] (b...Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate...

2010-07-01

380

Ionic Liquids as Catalysts for Sulfuric Acid Production and Cleaning of Flue Gases  

Microsoft Academic Search

\\u000a The present paper is concerned with catalytic pollution abatement of sulfur and nitrogen oxides in flue gases from industrial\\u000a sources. Especially fundamental and applied research on industrial catalysts and their model systems is presented with regards\\u000a to cleaning of flue gases from fossil fuel based power plants and plants producing sulfuric acid. Combined DeSOx and DeNOx processes are very common

Rasmus Fehrmann; K. M. Eriksen; S. B. Rasmussen; J. Winnick

381

Thermodynamic analysis of sorption reactions for the removal of sulfur from hot gases  

Microsoft Academic Search

Both coal combustion and coal gasification processes now require careful control of sulfur-bearing effluents. These needs\\u000a have stimulated an extensive amount of research and development (R & D) on simple and complex sulfur sorbent materials. The\\u000a application of thermodynamics in the study of the performance of these materials can and should be an effective approach.\\u000a Examples are described to show

J. H. Swisher; K. Schwerdtfeger

1992-01-01

382

Fuel Properties of Biodiesel\\/Ultra-Low Sulfur Diesel (ULSD) Blends  

Microsoft Academic Search

Biodiesel is an alternative fuel and fuel extender easily derived from vegetable oil or animal fat. In 2006, the US Environmental\\u000a Protection Agency mandated that maximum sulfur content of diesel fuels be reduced to 15 ppm to protect catalysts employed\\u000a in exhaust after-treatment devices. Processing to produce this ultra-low sulfur petrodiesel (ULSD) alters fuel lubricity,\\u000a density, cold flow, viscosity, and other

Robert O. Dunn

383

Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece.  

PubMed

Shallow-sea (5 m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1 m(2)) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the vent and non-vent sediments captured strong geochemical spatial patterns that varied from advective to diffusive sulfide transport from the subsurface. Despite clear visual evidence for the close association of vent organisms and hydrothermalism, the sulfur and oxygen isotope composition of pore fluids did not permit delineation of a biotic signal separate from an abiotic signal. Hydrogen sulfide (H2S) in the free gas had uniform ?(34)S values (2.5?±?0.28‰, n?=?4) that were nearly identical to pore water H2S (2.7?±?0.36‰, n?=?21). In pore water sulfate, there were no paired increases in ?(34)SSO4 and ?(18)OSO4 as expected of microbial sulfate reduction. Instead, pore water ?(34)SSO4 values decreased (from approximately 21‰ to 17‰) as temperature increased (up to 97.4°C) across each hydrothermal feature. We interpret the inverse relationship between temperature and ?(34)SSO4 as a mixing process between oxic seawater and (34)S-depleted hydrothermal inputs that are oxidized during seawater entrainment. An isotope mass balance model suggests secondary sulfate from sulfide oxidation provides at least 15% of the bulk sulfate pool. Coincident with this trend in ?(34)SSO4, the oxygen isotope composition of sulfate tended to be (18)O-enriched in low pH (<5), high temperature (>75°C) pore waters. The shift toward high ?(18)OSO4 is consistent with equilibrium isotope exchange under acidic and high temperature conditions. The source of H2S contained in hydrothermal fluids could not be determined with the present dataset; however, the end-member ?(34)S value of H2S discharged to the seafloor is consistent with equilibrium isotope exchange with subsurface anhydrite veins at a temperature of ~300°C. Any biological sulfur cycling within these hydrothermal systems is masked by abiotic chemical reactions driven by mixing between low-sulfate, H2S-rich hydrothermal fluids and oxic, sulfate-rich seawater. PMID:25183951

Gilhooly, William P; Fike, David A; Druschel, Gregory K; Kafantaris, Fotios-Christos A; Price, Roy E; Amend, Jan P

2014-01-01

384

Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece  

PubMed Central

Shallow-sea (5 m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1 m2) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the vent and non-vent sediments captured strong geochemical spatial patterns that varied from advective to diffusive sulfide transport from the subsurface. Despite clear visual evidence for the close association of vent organisms and hydrothermalism, the sulfur and oxygen isotope composition of pore fluids did not permit delineation of a biotic signal separate from an abiotic signal. Hydrogen sulfide (H2S) in the free gas had uniform ?34S values (2.5?±?0.28‰, n?=?4) that were nearly identical to pore water H2S (2.7?±?0.36‰, n?=?21). In pore water sulfate, there were no paired increases in ?34SSO4 and ?18OSO4 as expected of microbial sulfate reduction. Instead, pore water ?34SSO4 values decreased (from approximately 21‰ to 17‰) as temperature increased (up to 97.4°C) across each hydrothermal feature. We interpret the inverse relationship between temperature and ?34SSO4 as a mixing process between oxic seawater and 34S-depleted hydrothermal inputs that are oxidized during seawater entrainment. An isotope mass balance model suggests secondary sulfate from sulfide oxidation provides at least 15% of the bulk sulfate pool. Coincident with this trend in ?34SSO4, the oxygen isotope composition of sulfate tended to be 18O-enriched in low pH (<5), high temperature (>75°C) pore waters. The shift toward high ?18OSO4 is consistent with equilibrium isotope exchange under acidic and high temperature conditions. The source of H2S contained in hydrothermal fluids could not be determined with the present dataset; however, the end-member ?34S value of H2S discharged to the seafloor is consistent with equilibrium isotope exchange with subsurface anhydrite veins at a temperature of ~300°C. Any biological sulfur cycling within these hydrothermal systems is masked by abiotic chemical reactions driven by mixing between low-sulfate, H2S-rich hydrothermal fluids and oxic, sulfate-rich seawater. PMID:25183951

2014-01-01

385

Rubber vulcanizing agents comprising reaction products of sulfur and unsaturated hydrocarbons  

SciTech Connect

A process for making an improved vulcanizing agent is described comprising the steps of: A. providing starting materials consisting essentially of sulfur and an unsaturated reactant selected from at least one of d-limonene, 5-ethylidene-2-norbornene, styrene, and dicyclopentadiene; B. reacting the starting materials at a first temperature greater than the melting point of the sulfur and less than the temperature at which the sulfur begins to be converted to insoluble sulfur until substantially all of the unsaturated reactant is consumed, forming an intermediate product; C. maintaining the intermediate product at a second temperature greater than the melting point of the sulfur and the same as or different from the first temperature for a sufficient time to form an end product which is dispersible in rubber and provides less sulfur bloom than insoluble sulfur when incorporated in a rubber composition; and D. terminating the maintaining step by reducing the temperature of the end product, thereby maintaining the dispersibility of the end product in rubber.

Johansson, A.H.; Woodruff, D.; Flanders, S.K.; Swigert, J.L.

1988-04-26

386

The convention on long-range transboundary air pollution`s sulfur protocol  

SciTech Connect

The US is a signatory to the United Nations Economic Commission for Europe`s Convention on Long-Range Transboundary Air pollution (LRTAP). The signatories to the LRTAP Convention include most European countries, as well as the US and Canada. Over the past decade two Sulfur Protocols have been negotiated under the auspices of LRTAP; both were based on acidification concerns. The first, signed in 1985, committed countries to a 30% decrease in sulfur emissions relative to a 1980 baseline. The second, signed in 1994, committed countries to a 50--80% reduction in sulfur emissions. The latest protocol was based on the effects-based concept of critical loads of sulfur for protecting ecosystems from the effects of acidification. The US did not sign either sulfur protocol, but has participated in discussions leading up to both. This paper will present a discussion of the LRTAP Convention, the two sulfur protocols, the NO{sub x} Protocol, the US-Canada relationship on acid rain, the critical loads concept, and US participation in the LRTAP process (including the relationship between the sulfur protocols and Title IV of the Clean Air Act Amendments of 1990). The focus will be on key scientific and policy issues.

Leaf, D. [Environmental Protection Agency, Washington, DC (United States)

1995-12-31

387

Effect of sulfur and its compounds on the performance of graphite electrooxidation in molten carbonate  

NASA Astrophysics Data System (ADS)

Direct carbon fuel cells are promising power sources with their performance significantly depending on the electrooxidation activity of carbon fuel. The impurities in the carbon fuel may affect the anode reactions. Sulfur and some of its inorganic compounds (CaSO4, K2SO3, K2S, FeS2) were added in molten carbonate and their effect on graphite electrooxidation was investigated. Cyclic voltammograms of gold electrode with addition of these sulfur compounds showed CaSO4 was stable and other compounds were electrochemically oxidized to high valence state sulfur compounds at operating voltage range. Linear sweep voltammetry of graphite with addition of sulfur compounds exhibited enhanced current density compared to pure graphite electrooxidation. Chronoamperometry was carried out to examine steady-state test of graphite electrooxidation in presence of sulfur compounds and the results indicated the enhanced current densities were caused by improved Boudouard reaction for CaSO4 and sulfur electrooxidation for other compounds, respectively. These inorganic sulfur compounds had no impact on electrooxidation process of graphite.

Liu, Jia; Ye, Ke; Du, Mengmeng; Yin, Jinling; Cao, Dianxue; Wang, Guiling

2015-01-01

388

Production of elemental sulfur and methane from H{sub 2}S and CO{sub 2} derived from a coal desulfurization process. Final report, September 1, 1993--March 31, 1997  

SciTech Connect

The purpose of this study was to experimentally and theoretically investigate the feasibility of producing elemental sulfur, carbon monoxide, hydrogen and possible methane from hydrogen sulfide and carbon dioxide through catalytic reactions. A novel experimental system that could evaluate potential catalysts and adsorbents under controlled laboratory conditions was designed and constructed. Additionally an effective simulation program capable of providing valuable thermodynamic information on the reaction system was compiled. The following tasks have been performed: (1) design and construction of an experimental system for the catalyst preparation and catalyst screening studies including frequent modifications of the experimental setup to meet specific application needs; (2) installation and calibration of related analytical instruments, and investigation of the temperature distribution profile inside the reactor; (3) preparation, reduction, sulfidation of potential catalysts, and measurements of specific surface area of catalysts; (4) decomposition of H{sub 2}S under both non-catalytic condition and catalytic condition with the CoO-MoO{sub 3}-alumina catalyst at moderate temperatures around 550 C. Analyses of the product gas by gas chromatograph; and (5) thermodynamic studies on the theoretical conversions of H{sub 2}S for various temperatures, pressures and ratios of H{sub 2}S to CO{sub 2}. Based on the results of the above tasks, bench scale experiments were performed with the CoO-MoO{sub 3}-alumina catalyst at moderate temperatures around 550 C to investigate the adsorption effects of solid sorbents in order to remove sulfur from the reaction environment. Four kinds of adsorbents have been tested along with several designs of solid adsorbent feed systems.

Jiang, X.; Khang, S.J.; Keener, T.C.

1997-12-31

389

Biogeochemical Cycles of Carbon and Sulfur  

NASA Technical Reports Server (NTRS)

The elements carbon (C) and sulfur (S) interact with each other across a network of elemental reservoirs that are interconnected by an array of physical, chemical and biological processes. These networks are termed the biogeochemical C and S cycles. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. The element S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. This presentation describes the modern biogeochemical C and S cycles. Measurements are described whereby stable isotopes can help to infer the nature and quantitative significance of biological and geological processes involved in the C and S cycles. This lecture also summarizes the geological and climatologic aspects of the ancient C and S cycles, as well as the planetary and extraterrestrial processes that influenced their evolution over millions to billions of years.

DesMarais, David J.; DeVincenzi, D. (Technical Monitor)

2002-01-01

390

Supercritical thermodynamics of sulfur and nitrogen species  

SciTech Connect

Significant opportunity exists for the application of supercritical fluid (SCF) technology to coal processing, both for pretreatment of high sulfur coals, as well as liquefaction and treatment of coal liquids. Supercritical fluids are attractive solvents for a variety of coal processing applications because of their unusual solvating and mass transfer properties. Solubility studies have been carried out for a number of model coal and coal-liquid compounds, primarily in pure supercritical fluids. We are extending this database of model coal compound equilibria using modern techniques that have the advantage of being much more rapid than traditional techniques. Cosolvent effects on solubility are being investigated over a variety of solvent properties. In addition, specific molecular interactions are being investigated through spectroscopic techniques. The resulting data is being used to develop a chemical-physical equation of state (EOS) model of SCF solution with meaningful parameters. The equation of state will be used to predict solubility behavior, which will permit the design and tailoring of SCF cosolvent systems for specific coal processing applications.

Eckert, C.A.

1991-01-01

391

Dielectric strength of sulfur hexafluoride upon condensation  

SciTech Connect

The behavior of sulfur hexafluoride in a sealed high-voltage device has been modeled for cooling to the condensation point of the insulating medium. The temperature dependences of the breakdown voltages of sulfur hexafluoride have been investigated for several interelectrode separations. The dielectric strength has been shown to decrease upon condensation with formation of a bridge of boiling liquid phase between the electrodes.

Antonov, A.V.; Lyapin, A.G.; Popkov, V.I.

1983-01-01

392

An Aerosol Condensation Model for Sulfur Trioxide  

Microsoft Academic Search

This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and\\/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially

2008-01-01

393

Sulfur diagnostic criteria for French prune trees  

Microsoft Academic Search

One year old Marianna 2624 (Prunus cerasifera X P. munsoniana) trees grafted with French prunes (P. domestica) were grown in the greenhouse in pots containing vermiculite and supplied with graded amounts of sulfate?sulfur (SO4?S) to study the methods of evaluating sulfur (S). Tree fresh weight gain was recorded. Leaf samples were analyzed for different S fractions. Chlorophyll concentration of leaves

Izhar Ul Haq; Robert M. Carlson

1993-01-01

394

Ambient Air Monitoring for Sulfur Compounds  

ERIC Educational Resources Information Center

A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

Forrest, Joseph; Newman, Leonard

1973-01-01

395

Leaching behavior of ilmenite with sulfuric acid  

Microsoft Academic Search

A study of the rate of dissolution of ilmenite in sulfuric acid solutions has been carried out. The effects of temperature, particle size, stirring speed, and concentration of sulfuric acid on the rate of dissolution of ilmenite has been investigated. Temperature range studied in this investigation was 88° to 115°C, and the Arrhenius activation energy was found to be 64.4

K. N. Han; T. Rubcumintara; M. C. Fuerstenau

1987-01-01

396

The Microbial Karst Sulfuric Acid Dynamo  

Microsoft Academic Search

The original model for sulfuric acid speleogenesis attributes limestone dissolution to the oxidation of gaseous H2S to sulfuric acid on limestone cave walls (Egemeier 1981). This model has recently been reexamined in Lower Kane Cave, Wyoming (USA), where the most intense limestone dissolution appears to be the result of microbial colonization of limestone surfaces below the water table (Engel et

E. Lyon; K. Meyer; B. Koffman; S. Galdenzi; J. Macalady

2004-01-01

397

Sulfuric Acid and Water: Paradoxes of Dilution  

ERIC Educational Resources Information Center

On equilibrium properties of aqueous solutions of sulfuric acid, Julius Thomsen has marked that the heat evolved on diluting liquid sulfuric acid with water is a continuous function of the water used, and excluded absolutely the acceptance of definite hydrates as existing in the solution. Information about thermochemical measurement, a discussion…

Leenson, I. A.

2004-01-01

398

SURFACE REACTIONS OF OXIDES OF SULFUR  

EPA Science Inventory

Surface reactions of several sulfur-containing molecules have been studied in order to understand the mechanism by which sulfate ions are formed on atmospheric aerosols. At 25C the heterogeneous oxidation of SO2 by NO2 to sulfuric acid and sulfate ions occurred on hydrated silica...

399

Heat pipes for sodium-sulfur batteries  

Microsoft Academic Search

The objective of this program was to develop a variable conductance heat pipe (VCHP) for the thermal management of sodium-sulfur batteries. The VCHP maintains the sodium sulfur battery within a specified temperature rise limit (20 C) while the battery discharges a thermal load from 0 watts to 500 watts. A preliminary full scale thermal management design was developed for the

John R. Hartenstine

1989-01-01

400

Estimation of sulfur deposition in South Korea  

Microsoft Academic Search

Dry and wet depositions of sulfur have been estimated using the routinely available meteorological data at 70 sites, air-monitored data at 27 sites and upper air soundings made daily twice (0000 and 1200 UTC) at three stations over South Korea for 4yr from 1994 to 1997. The average annual total dry deposition and wet deposition of sulfur in South Korea

Soon-Ung Park; Hee-Jin In; Si-Wan Kim; Young-Hee Lee

2000-01-01

401

Heterogeneous photocatalytic reactions of sulfur aromatic compounds.  

PubMed

Sulfur aromatic compounds, such as mono-, di-, tri-, and tetraalkyl-substituted thiophene, benzothiophenes, dibenzothiophenes, are the molecular components of many fossils (petroleum, oil shale, tar sands, bitumen). Structural units of natural, cross-linked heteroaromatic polymers present in brown coals, turf, and soil are similar to those of sulfur aromatic compounds. Many sulfur aromatic compounds are found in the streams of petroleum refining and upgrading (naphthas, gas oils) and in the consumer products (gasoline, diesel, jet fuels, heating fuels). Besides fossils, the structural fragments of sulfur aromatic compounds are present in molecules of certain organic semiconductors, pesticides, small molecule drugs, and in certain biomolecules present in human body (pheomelanin pigments). Photocatalysis is the frontier area of physical chemistry that studies chemical reactions initiated by absorption of photons by photocatalysts, that is, upon electronic rather than thermal activation, under "green" ambient conditions. This review provides systematization and critical review of the fundamental chemical and physicochemical information on heterogeneous photocatalysis of sulfur aromatic compounds accumulated in the last 20-30 years. Specifically, the following topics are covered: physicochemical properties of sulfur aromatic compounds, major classes of heterogeneous photocatalysts, mechanisms and reactive intermediates of photocatalytic reactions of sulfur aromatic compounds, and the selectivity of these reactions. Quantum chemical calculations of properties and structures of sulfur aromatic compounds, their reactive intermediates, and the structure of adsorption complexes formed on the surface of the photocatalysts are also discussed. PMID:21809426

Samokhvalov, Alexander

2011-11-18

402

Mitigation of Sulfur Effects on a Lean NOx Trap Catalyst by Sorbate Reapplication  

SciTech Connect

Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by >90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as "regeneration" since the catalyst is reactivated for more NOx trapping. Natural gas combusted over partial oxidation catalysts in the exhaust can be used to obtain the rich exhaust conditions necessary for catalyst regeneration. Thus, the lean NOx trap technology is well suited for lean natural gas engine applications. One potential limitation of the lean NOx trap technology is sulfur poisoning. Sulfur compounds directly bond to the NOx trapping sites of the catalyst and render them ineffective; over time, the sulfur poisoning leads to degradation in overall NOx reduction performance. In order to mitigate the effects of sulfur poisoning, a process has been developed to restore catalyst activity after sulfur poisoning has occurred. The process is an aqueous-based wash process that removes the poisoned sorbate component of the catalyst. A new sorbate component is reapplied after removal of the poisoned sorbate. The process is low cost and does not involve reapplication of precious metal components of the catalyst. Experiments were conducted to investigate the feasibility of the washing process on a lean 8.3-liter natural gas engine on a dynamometer platform. The catalyst was rapidly sulfur poisoned with bottled SO2 gas; then, the catalyst sorbate was washed and reapplied and performance was re-evaluated. Results show that the sorbate reapplication process is effective at restoring lost performance due to sulfur poisoning. Specific details relative to the implementation of the process for large stationary natural gas engines will be discussed.

Parks, II, James E [ORNL

2007-01-01

403

ENERGY EFFICIENCY LIMITS FOR A RECUPERATIVE BAYONET SULFURIC ACID DECOMPOSITION REACTOR FOR SULFUR CYCLE THERMOCHEMICAL HYDROGEN PRODUCTION  

SciTech Connect

A recuperative bayonet reactor design for the high-temperature sulfuric acid decomposition step in sulfur-based thermochemical hydrogen cycles was evaluated using pinch analysis in conjunction with statistical methods. The objective was to establish the minimum energy requirement. Taking hydrogen production via alkaline electrolysis with nuclear power as the benchmark, the acid decomposition step can consume no more than 450 kJ/mol SO{sub 2} for sulfur cycles to be competitive. The lowest value of the minimum heating target, 320.9 kJ/mol SO{sub 2}, was found at the highest pressure (90 bar) and peak process temperature (900 C) considered, and at a feed concentration of 42.5 mol% H{sub 2}SO{sub 4}. This should be low enough for a practical water-splitting process, even including the additional energy required to concentrate the acid feed. Lower temperatures consistently gave higher minimum heating targets. The lowest peak process temperature that could meet the 450-kJ/mol SO{sub 2} benchmark was 750 C. If the decomposition reactor were to be heated indirectly by an advanced gas-cooled reactor heat source (50 C temperature difference between primary and secondary coolants, 25 C minimum temperature difference between the secondary coolant and the process), then sulfur cycles using this concept could be competitive with alkaline electrolysis provided the primary heat source temperature is at least 825 C. The bayonet design will not be practical if the (primary heat source) reactor outlet temperature is below 825 C.

Gorensek, M.; Edwards, T.

2009-06-11

404

Advanced product recovery: Direct catalytic reduction of sulfur dioxide to elemental sulfur. Third quarterly technical progress report  

SciTech Connect

More than 170 wet scrubber systems applied to 72,000 MW of US, coal-fired, utility boilers are in operation or under construction. In these systems, the sulfur dioxide removed form the boiler flue gas is permanently bound to a sorbent material, such as lime or limestone. The sulfated sorbent must be disposed of as a waste product or, in some cases, sold as a byproduct (e.g. gypsum). The use of regenerable sorbent technologies has the potential to reduce or eliminate solid waste production, transportation and disposal. Arthur D. Little, Inc., together with its industry and commercialization advisor, Engelhard Corporation, and its university partner, Tufts, plans to develop and scale-up an advanced, byproduct recovery technology that is a direct, catalytic process for reducing sulfur dioxide to elemental sulfur. The principal objective of the Phase 1 program is to identify and evaluate the performance of a catalyst which is robust and flexible with regard to choice of reducing gas. In order to achieve this goal, they have planned a structured program including: market/process/cost/evaluation; lab-scale catalyst preparation/optimization studies; lab-scale, bulk/supported catalyst kinetic studies; bench-scale catalyst/process studies; and utility review. This catalytic process reduces SO{sub 2} over a fluorite-type oxide (such as ceria and zirconia). The catalytic activity can be significantly promoted by active transition metals, such as copper. This type of mixed metal oxide catalyst has stable activity, high selectivity for sulfur production, and is resistant to water and carbon dioxide poisoning.

NONE

1996-07-01

405

Drug Targets in Mycobacterial Sulfur Metabolism  

PubMed Central

The identification of new antibacterial targets is urgently needed to address multidrug resistant and latent tuberculosis infection. Sulfur metabolic pathways are essential for survival and the expression of virulence in many pathogenic bacteria, including Mycobacterium tuberculosis. In addition, microbial sulfur metabolic pathways are largely absent in humans and therefore, represent unique targets for therapeutic intervention. In this review, we summarize our current understanding of the enzymes associated with the production of sulfated and reduced sulfur-containing metabolites in Mycobacteria. Small molecule inhibitors of these catalysts represent valuable chemical tools that can be used to investigate the role of sulfur metabolism throughout the Mycobacterial lifecycle and may also represent new leads for drug development. In this light, we also summarize recent progress in the development of inhibitors of sulfur metabolism enzymes. PMID:17970225

Bhave, Devayani P.; Muse, Wilson B.; Carroll, Kate S.

2011-01-01

406

Electron backscatter diffraction on femtosecond laser sulfur hyperdoped silicon  

NASA Astrophysics Data System (ADS)

This paper analyzes the impact of femtosecond laser pulse irradiation on the crystallinity of silicon wafers by means of electron backscatter diffraction (EBSD) measurements. EBSD based image quality maps and orientation imaging microscopy maps are correlated to the grade of the silicon crystallinity. We analyze the impact of accumulated net laser irradiation originating from a laser spot overlap that is necessary to process macroscopic areas, e.g., for sulfur doping of semiconductor devices. Furthermore, we demonstrate that post processing annealing recovers crystallinity and therefore allows fs-laser processed silicon to be used in semiconductor device manufacturing.

Gimpel, Thomas; Höger, Ingmar; Falk, Fritz; Schade, Wolfgang; Kontermann, Stefan

2012-09-01

407

A scalable graphene sulfur composite synthesis for rechargeable lithium batteries with good capacity and excellent columbic efficiency.  

PubMed

Sulfur nanoparticles wrapped with a conductive graphene framework was synthesized with a high sulfur loading through a scalable one-step process. The graphene-coated sulfur nanostructured composite, when used as cathode for lithium sulfur battery, shows a reversible capacity of 808 mAh g(-1) at a rate of 210 mA g(-1) and an average columbic efficiency of ?98.3% over 100 cycles. It is found that graphene oxide (GO) with a porous structure offers flexible confinement function that helps prevent the loss of active materials, thus extending the cycling life of the electrode. Moreover, reduced graphene oxide provides a conductive network surrounding the sulfur particles, which facilitates both electron transport and ion transportation. This novel one-step, all-solution-based process is scalable and provides a promising approach for potential industrial applications. PMID:24555988

Gao, Xianfeng; Li, Jianyang; Guan, Dongsheng; Yuan, Chris

2014-03-26

408

Electrochemical membrane process for flue gas desulfurization  

Microsoft Academic Search

A flue gas desulfurization process being developed for coal-fired power plants removes and concentrates sulfur oxides (SO[sub x]). The key element is an electrochemical cell using a sulfur oxide selective membrane. It achieves 90% sulfur oxide removal with near 100% electric current efficiency. Recent research has focused on improving the structure of the electrochemical membrane and its interface with the

Dennis J. McHenry; Jack Winnick

1994-01-01

409

Sulfur species in volcanic gases.  

PubMed

A new analytical method for the determination of the sulfur species (SO2, H2S, S8(0)) in volcanic gases is proposed by revising, updating, and improving previous methods. The most significant advantages of the proposed procedure can briefly be summarized, as follows: (i) the reaction among sulfur species stops during the gas sampling by using preevacuated thorion-tapped vials with purified 0.15M Cd(OH)2 in 4 M NaOH to favor the precipitation of H2S as CdS; (ii) all the sulfur species (SO2, H2S, S8(0)) are analyzed by ion chromatography, after conversion to SO4, which allows the detection limit to be lowered significantly with respect to the previous studies; (iii) appropriate aliquots from intermediate steps may be used to determine other species commonly present in volcanic gases such as CO2, HCI, HF, HBr, HI, and so forth; (iv) determination of all the other gas species is not jeopardized by the proposed method, i.e., one single vial can be used for analyzing the full chemical composition of a volcanic gas with the exception of NH3. Statistical parameters calculated from gas sampling data at the F5 crater fumarole in Vulcano Island (Aeolian Islands, southern Italy), suggest that the standard error of mean (s/ root n) is higher for S (0.10), followed by SO2, H2S, and CO2 (0.04, 0.038, and 0.028, respectively). SO2 shows the higher variation coefficient (12.1%) followed by H2S, S, and CO2 (5.7, 1.5, and 0.8%, respectively). Furthermore, if the time dependence of sampling is taken into account, the measured values, instead of fluctuating in a random manner, tend to follow systematic patterns, out of statistical control, possibly suggesting a sort of natural fluctuation of the volcanic system. Other crater fumaroles from volcanic systems located in different geodynamical areas (Hawaii, USA, El Chichon, Mexico, Poas, Costa Rica) have been analyzed as well. PMID:11510838

Montegrossi, G; Tassi, F; Vaselli, O; Buccianti, A; Garofalo, K

2001-08-01

410

Exogenic controls on sulfuric acid hydrate production at the surface of Europa  

NASA Astrophysics Data System (ADS)

External agents have heavily weathered the visible surface of Europa. Internal and external drivers competing to produce the surface we see include, but are not limited to: aqueous alteration of materials within the icy shell, initial emplacement of endogenic material by geologic activity, implantation of exogenic ions and neutrals from Jupiter's magnetosphere, alteration of surface chemistry by radiolysis and photolysis, impact gardening of upper surface layers, and redeposition of sputtered volatiles. Separating the influences of these processes is critical to understanding the surface and subsurface compositions at Europa. Recent investigations have applied cryogenic reflectance spectroscopy to Galileo Near-Infrared Mapping Spectrometer (NIMS) observations to derive abundances of surface materials including water ice, hydrated sulfuric acid, and hydrated sulfate salts. Here we compare derived sulfuric acid hydrate (H2SO4·nH2O) abundance with weathering patterns and intensities associated with charged particles from Jupiter's magnetosphere. We present models of electron energy, ion energy, and sulfur ion number flux as well as the total combined electron and ion energy flux at the surface to estimate the influence of these processes on surface concentrations, as a function of location. We found that correlations exist linking both electron energy flux (r?0.75) and sulfur ion flux (r=0.93) with the observed abundance of sulfuric acid hydrate on Europa. Sulfuric acid hydrate production on Europa appears to be limited in some regions by a reduced availability of sulfur ions, and in others by insufficient levels of electron energy. The energy delivered by sulfur and other ions has a much less significant role. Surface deposits in regions of limited exogenic processing are likely to bear closest resemblance to oceanic composition. These results will assist future efforts to separate the relative influence of endogenic and exogenic sources in establishing the surface composition.

Dalton, J. B.; Cassidy, T.; Paranicas, C.; Shirley, J. H.; Prockter, L. M.; Kamp, L. W.

2013-03-01

411

Toward Understanding the Effect of Low-Activity Waste Glass Composition on Sulfur Solubility  

SciTech Connect

The concentration of sulfur in nuclear waste glass melter feed must be maintained below the point where salt accumulates on the melt surface. The allowable concentrations may range from 0.37 to over 2.05 weight percent (of SO3 on a calcined oxide basis). If the amount of sulfur exceeds its tolerance level a molten salt will accumulate and upset melter operations and potentially shorten melter useful life. Therefore relatively conservative limits have been placed on sulfur loading in melter feed which in-turn significantly impacts the amount of glass that will be produced, in particular at the Hanford site. Crucible-scale sulfur solubility data and scaled melter sulfur tolerance data have been collected on simulated Hanford waste glasses over the last 15 years. These data were compiled and analyzed. A model was developed to predict the solubility of SO3 in glass based on 312 individual glass compositions. This model was shown to well represent the data, accounting for over 80% of the variation in data and was well validated. The model was also found to accurately predict the tolerance for sulfur in melter feed based on 19 scaled melter tests. The model is appropriate for control of waste glass processing which includes uncertainty quantification. The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that most increase sulfur solubility are Li2O > V2O5 ? TiO2 < CaO < P2O5 ? ZnO. The components that most decrease sulfur solubility are Cl > Cr2O3 > SiO2 ? ZrO2 > Al2O3.

Vienna, John D.; Kim, Dong-Sang; Muller, Isabelle S.; Piepel, Gregory F.; Kruger, Albert A.

2014-10-25

412

A three-dimensional study of the tropospheric sulfur cycle  

NASA Astrophysics Data System (ADS)

The global tropospheric distributions of seven important sulfur species were simulated with a global three-dimensional chemistry-transport model (IMAGES). Surface emission and deposition velocity maps were established for use as lower boundary conditions in the model. While anthropogenic SO2 emissions are by far the largest sulfur source in the northern midlatitudes, reduced sulfur compounds, notably dimethyl sulfide (DMS) predominate over most remote areas. Simulations were performed for the present-day (˜ 1985) atmosphere. The calculated distributions are compared with available observations. The model results are found to be generally within a factor of (at most) 2-3 of long-term observations. Comparison with campaign measurements is more difficult, mostly due to the strong dependence of sulfur species concentrations on local meteorological conditions. The results, however, indicate the need for future model refinements, especially with respect to biogenic emission estimates and parameterization of cloud processes. A sensitivity study is presented to discuss the uncertainties of the results related to several parameters (the decoupling of wet scavenging and convective transport for soluble species, volcanoes emission and deposition velocities). Results are also discussed in terms of global budgets and related variables and processes. Around 125 Tg S/yr of non-sea-salt (nss) sulfur compounds (DMS, CS2, H2S, COS, and SO2) are injected into the atmosphere. The balance is mainly maintained by nss-sulfates wet and dry deposition, and by SO2 dry deposition (94% of total sulfur deposition). It is found that DMS oxidation represents the main contribution to SO2 chemical production (80% of the chemical sources), and that the major sink of SO2 is provided by in-cloud oxidation (90% of the chemical sinks), under the assumption that all SO2 incorporated into clouds is oxidized. The calculated annual wet deposition of sulfates reaches 3 g S m-2 yr-1 over Europe and North America, while it is usually lower than 0.5 g S m-2 yr-1 in remote parts of the world. Estimations for the global lifetimes are 0.9 day for DMS, 4 days for CS2, 2.2 days for H2S, 0.6 day for SO2, 0.18 day for DMSO, 6.1 days for MSA, and 4.7 days for nss-sulfates.

Pham, M.; Müller, J.-F.; Brasseur, G. P.; Granier, C.; MéGie, G.

1995-12-01

413

Deactivation of metastable single-crystal silicon hyperdoped with sulfur  

SciTech Connect

Silicon supersaturated with sulfur by ion implantation and pulsed laser melting exhibits broadband optical absorption of photons with energies less than silicon's band gap. However, this metastable, hyperdoped material loses its ability to absorb sub-band gap light after subsequent thermal treatment. We explore this deactivation process through optical absorption and electronic transport measurements of sulfur-hyperdoped silicon subject to anneals at a range of durations and temperatures. The deactivation process is well described by the Johnson-Mehl-Avrami-Kolmogorov framework for the diffusion-mediated transformation of a metastable supersaturated solid solution, and we find that this transformation is characterized by an apparent activation energy of E{sub A}=1.7 ± 0.1 eV. Using this activation energy, the evolution of the optical and electronic properties for all anneal duration-temperature combinations collapse onto distinct curves as a function of the extent of reaction. We provide a mechanistic interpretation of this deactivation based on short-range thermally activated atomic movements of the dopants to form sulfur complexes.

Simmons, C. B.; Akey, Austin J.; Sullivan, Joseph T.; Buonassisi, Tonio [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Krich, Jacob J. [University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada)] [University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada); Recht, Daniel; Aziz, Michael J. [Harvard School of Engineering and Applied Sciences, Cambridge, Massachusetts 02138 (United States)] [Harvard School of Engineering and Applied Sciences, Cambridge, Massachusetts 02138 (United States)

2013-12-28

414

Removal of nitrogen and sulfur from oil-shale  

SciTech Connect

This patent describes a process for enhancing the removal of nitrogen and sulfur from oil-shale. The process consists of: (a) contacting the oil-shale with a sufficient amount of an aqueous base solution comprised of at least a stoichiometric amount of one or more alkali metal or alkaline-earth metal hydroxides based on the total amount of nitrogen and sulfur present in the oil-shale. Also necessary is an amount sufficient to form a two-phase liquid, solid system, a temperature from about 50/sup 0/C to about 350/sup 0/C., and pressures sufficient to maintain the solution in liquid form; (b) separating the effluents from the treated oil-shale, wherein the resulting liquid effluent contains nitrogen moieties and sulfur moieties from the oil-shale and any resulting gaseous effluent contains nitrogen moieties from the oil-shale, and (c) converting organic material of the treated oil-shale to shale-oil at a temperature from about 450/sup 0/C to about 550/sup 0/C.

Olmstead, W.N.

1986-01-28

415

Synthesis of thiocarbamate salts from amines, sulfur, and carbon monoxide  

SciTech Connect

Sulfur reacts with carbon monoxide and amines without a catalyst at 100-160{degrees}C and 10-100 atm for 1-4 h. The reaction products of primary amines are symmetric ureas. Under the same conditions, secondary amines form thiocarbamic acid salts, which are not converted to tetrasubstituted ureas. In the presence of primary amines at 100-160{degrees}C, they afford trisubstituted ureas, some of whose representatives are pesticides. The same products are formed directly in the carbonylation of a mixture of primary and secondary amines without isolation of intermediate thiocarbamic acid salts. In the presence of catalytic amounts of selenium, the reaction of sulfur with carbon monoxide and amines occurs at atmospheric pressure and affords N-substituted thiocarbamic acid salts from both secondary and primary amines. In the current work the authors present some of the characteristics of these processes. 10 refs., 5 figs., 2 tabs.

Manov-Yuvenskii, V.I.; Kuznetsov, S.L.

1992-05-20

416

Increased accumulation of sulfur in lake sediments of the high arctic.  

PubMed

We report a synchronous increase in accumulation of reduced inorganic sulfur since c. 1980 in sediment cores from eight of nine lakes studied in the Canadian Arctic and Svalbard (Norway). Sediment incubations and detailed analyses of sediment profiles from two of the lakes indicate that increases in sulfur accumulation may be due ultimately to a changing climate. Warming-induced lengthening of the ice-free season is resulting in well-documented increases in algal production and sedimentation of the resulting detrital matter. Algal detritus is a rich source of labile carbon, which in these sediments stimulates dissimilatory sulfate reduction. The sulfide produced is stored in sediment (as acid volatile sulfide), converted to other forms of sulfur, or reoxidized to sulfate and lost to the water column. An acceleration of the sulfur cycle in Arctic lakes could have profound effects on important biogeochemical processes, such as carbon burial and mercury methylation. PMID:20973547

Drevnick, Paul E; Muir, Derek C G; Lamborg, Carl H; Horgan, Martin J; Canfield, Donald E; Boyle, John F; Rose, Neil L

2010-11-15

417

Stabilization of Sulfur Cathode with Poly-peri-naphthalene for High Electrochemical Performance  

NASA Astrophysics Data System (ADS)

With the layered structure and high conductivity similar to those of graphite, the conductive polymer poly-peri-naphthalene was used to modify sulfur electrode Structure and properties of PPN, and the sulfur/Poly-peri-naphthalene (S/PPN) composite were characterized using IR, Raman spectroscopy, x-ray diffraction, thermogravimetry, and scanning electron microscopy. Compared with carbon/sulfur composite cathode, the S/PPN cathode showed superior discharge capacity, high cycle stability and low electrochemical impedance. An initial discharge capacity of 1084.2 mAh g-1 was delivered using the S/PPN cathode at a current density of 400 mA g-1, while the discharge capacity of 919.7 mAh g-1 was remained after 50 cycles. PPN played a role of framework in the S/PPN electrode, which can stabilize the sulfur in the charge/discharge processes.

Wu, Bo-rong; Chen, Fei-biao; Xiong, Yun-kui; Liao, Wei-lin; Ren, Yong-huan; Wu, Feng

2014-12-01

418

Phanerozoic cycles of sedimentary carbon and sulfur  

PubMed Central

A reservoir model of a Recent steady-state sedimentary system in which the reduced sulfur and oxidized sulfur reservoirs were coupled with the oxidized carbon and reduced carbon reservoirs was constructed. The time curve of the sulfur isotope ratios of the sedimentary sulfate reservoir was used to drive the model back to the beginning of Cambrian time (600 million years ago), producing the reservoir sizes and isotope values and material fluxes of the carbon-sulfur system. The predicted values of carbon isotope ratios of the carbonate reservoir agree well with observed values, showing that the model is basically sound. Some general conclusions from this success are (i) material flux rates in the carbon-oxygen-sulfur system of the geologic past (averaged over tens of millions of years) lie within about a factor of 2 of Recent rates. (ii) The oxidation-reduction balances of Phanerozoic time were dominated by reciprocal relationships between carbon and sulfur compounds. (iii) The rate of production of atmospheric oxygen by storage in sediments of organic carbon of photosynthetic origin increased from the Cambrian Period to the Permian Period and declined somewhat from the Permian Period to the Present. (iv) The storage of oxygen in oxidized sulfur compounds kept pace (within the limits of the data) with oxygen production. (v) Transfer of oxygen from CO2 to SO4 from the Cambrian to the Permian Period was several times the Recent free oxygen content of the atmosphere. PMID:16593066

Garrels, Robert M.; Lerman, Abraham

1981-01-01

419

Sulfur isotope signals in molybdenite - a persistent message from the past  

NASA Astrophysics Data System (ADS)

Trace elements in ore deposits, gleaned from minerals or isolated inclusions, are used by economic geologists to speculate on source and to model ore-forming processes. As well, sulfur isotope data are often obtained for sulfide minerals, but the interpretation of these isotopic data for understanding ore genesis has been thin - often simplistically concluding a “mantle source” or “crustal source”. With starting parameters for ore-bound metals that may include magmatic-hydrothermal components from lower crust with its own initial biogenic and redox history, subseqeuntly compromised by metamorphic processes, just about any source can be invoked to explain a measured range of sulfur isotopic data. Added constraints are essential. The sulfur isotopic composition of pyrite in magmatic-hydrothermal systems ranges widely, from negative to positive per mil values, as is also the case for other ore-forming sulfides of Cu, Pb, and Zn. In contrast, from Paleoarchean to Recent, the sulfur isotopic composition of molybdenite (molybdenum disulfide) is eerily consistent and decisively positive (?34S commonly +2 to +6 per mil). This requires either an unwavering source for sulfur in all magmatic-hydrothermal molybdenites, and/or a template for a process that has been perfectly reproduced throughout earth history. A sedimentary sulfur source would have to be extraordinarily unique through time to fit the bill. Molybdenite, a common mineral in magmatic-hydrothermal ore deposits, is clearly tied to the magmatic system, occurring as disseminations and/or generations of veins spatially associated with evolved intrusive phases. Thus, the metals have traveled a finite distance from their source, forcing reliance on geochemical tracers to elucidate controlling processes. Molybdenum isotope ratios in molybdenite from some individual deposits span a large range of values, comparable to the range observed in all rock types. Rather than revealing source, the Mo isotopes reflect Rayleigh fractionation processes during episodes of late-magmatic volatile release that create quartz-molybdenite veins [1]. Similar fractionation cannot occur in sulfur isotopes; instead, the constant sulfur isotope ratios reflect quantitative reduction of magmatic SO2 to reduced sulfur species in hydrothermal fluids. Here we postulate on the starting conditions and the oxidative-reductive hydrothermal journey taken by molybdenum and sulfur - seemingly along unique paths - prior to their precipitation as the disulfide molybdenite. While scientific research is often pointed toward exploring inconsistencies and perturbations in the geologic record, just as important is to discover and explain the remarkable consistencies maintained over geologic time. [1] Hannah, J.L., Stein, H.J., Wieser, M.E., de Laeter, J.R., and Varner, M. (2007) Mo isotope variations in molybdenite: Vapor transport and Rayleigh fractionation of Mo, Geology 35: 703-706.

Stein, H. J.; Hannah, J. L.

2010-12-01

420

Degradation of Oil Shale by Sulfur-Oxidizing Bacteria  

PubMed Central

Approximately 40% of oil shale can be solubilized by the action of sulfur-oxidizing bacteria. Thiobacillus thiooxidans and Thiobacillus concretivorous are equally effective in solubilization. Continuous leaching experiments show that this process can be completed within 14 days. The growth of Thiobacillus and the production of acid were measured under several conditions. Almost all of the CaMg(CO3)2 was removed by this process, leaving a complex of silica and kerogen that could be burned as low-energy fuel. The silica-kerogen complex had not yet been biologically degraded. PMID:4370628

Findley, J.; Appleman, M. D.; Yen, T. F.

1974-01-01

421

Advanced sulfur control concepts in hot-gas desulfurization technology: Phase 1, Feasibility of the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents  

SciTech Connect

This topical report de-scribes the results of Phase 1 research performed during the first six months of a three-year contract to study the feasibility of the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents. Much effort has gone into the development of a high-temperature meal oxide sorbent process for removal of H{sub 2}S from the coal gas. A number of sorbents based upon metals such as zinc, iron, manganese and others have been studied. In order for high temperature desulfurization to be economical it is necessary that the sorbents be regenerated to permit multicycle operation. Current methods of sorbent regeneration involve oxidation of the metal sulfide to reform the metal oxide and free the sulfur as SO{sub 2}. An alternate regeneration process in which the sulfur is liberated in elemental form is preferable. The overall objective of the current research is to study simpler and economically superior processing of known sorbents capable of producing elemental sulfur during regeneration. This topical report summarizes the first steps of this effort. A literature search has been completed to identify possible regeneration concepts and to collect relevant thermodynamic, kinetic, and process data. Three concepts involving reaction with SO{sub 2}, partial oxidation using an O{sub 2} {minus} H{sub 2}O mixture, and steam regeneration have been identified. The first two concepts result in the direct production of elemental sulfur while H{sub 2}S is the product of steam regeneration. This concept is of potential interest, however, since existing Claus technology can be used to convert H{sub 2}S to elemental sulfur. Following the literature search, a thermodynamic analysis, based upon free-energy minimization was carried out to evaluate candidate sorbents for possible use with the three regeneration concepts.

Lopez, A.; White, J.; Groves, F.R.; Harrison, D.P.

1994-10-01

422

Quantifying Individual Potential Contributions of the Hybrid Sulfur Electrolyzer  

E-print Network

transport to the anode influences the concentration of the sulfuric acid produced. The resulting sulfuric loss is the diffusion of SO2 through the sulfuric acid to the catalyst site. Here, we extend our and correlated the operating potential to the sulfuric acid concentration produced at the anode.15-17 We have

Weidner, John W.

423

CONSTRUCTION OF A PROTOTYPE SULFURIC ACID MIST MONITOR  

EPA Science Inventory

A prototype sulfuric acid mist monitor has been constructed for the purpose of detecting sulfuric acid-sulfur trioxide. The monitor utilized the selective condensation method with subsequent determination of sulfuric acid by measuring the conductivity of an aqueous isopropanol so...

424

46 CFR 151.50-21 - Sulfuric acid.  

Code of Federal Regulations, 2012 CFR

...5 2012-10-01 2012-10-01 false Sulfuric acid. 151.50-21 Section 151.50-21 Shipping...CARGOES Special Requirements § 151.50-21 Sulfuric acid. (a) How sulfuric acid may be carried. (1) Sulfuric acid...

2012-10-01

425

46 CFR 151.50-21 - Sulfuric acid.  

Code of Federal Regulations, 2014 CFR

...5 2014-10-01 2014-10-01 false Sulfuric acid. 151.50-21 Section 151.50-21 Shipping...CARGOES Special Requirements § 151.50-21 Sulfuric acid. (a) How sulfuric acid may be carried. (1) Sulfuric acid...

2014-10-01

426

46 CFR 151.50-21 - Sulfuric acid.  

Code of Federal Regulations, 2013 CFR

...5 2013-10-01 2013-10-01 false Sulfuric acid. 151.50-21 Section 151.50-21 Shipping...CARGOES Special Requirements § 151.50-21 Sulfuric acid. (a) How sulfuric acid may be carried. (1) Sulfuric acid...

2013-10-01

427

Geochemical and cosmochemical cycles involving sulfur, sulfide, sulfite and sulfate  

Microsoft Academic Search

Raman spectra of aqueous systems containing sulfur dioxide, elemental sulfur and sulfate indicate that the equilibrium between these species is catalyzed by elemental sulfur. Therefore, dynamic equilibrium can be expected under conditions prevalent on Venus, on Io and in epigenic sulfur deposits.

B. Meyer; L. Peter; M. Ospina

1979-01-01

428

Improvement of cycle property of sulfur electrode for lithium\\/sulfur battery  

Microsoft Academic Search

Although a theoretical specific capacity of lithium\\/sulfur redox couple battery is 1672mAh\\/g, lithium\\/sulfur battery has the serious problems of low utilization of active material and poor rechargeability, due to the loss of active material in the form of soluble polysulfides (Li2Sn, n>2). In this study, carbon nano-fiber having average fiber diameter of 150nm was added into the sulfur electrode in

Young-Jin Choi; Ki-Won Kim; Hyo-Jun Ahn; Jou-Hyeon Ahn

2008-01-01

429

Mass-independent sulfur of inclusions in diamond and sulfur recycling on early Earth.  

PubMed

Populations of sulfide inclusions in diamonds from the Orapa kimberlite pipe in the Kaapvaal-Zimbabwe craton, Botswana, preserve mass-independent sulfur isotope fractionations. The data indicate that material was transferred from the atmosphere to the mantle in the Archean. The data also imply that sulfur is not well mixed in the diamond source regions, allowing for reconstruction of the Archean sulfur cycle and possibly offering insight into the nature of mantle convection through time. PMID:12493909

Farquhar, J; Wing, B A; McKeegan, K D; Harris, J W; Cartigny, P; Thiemens, M H

2002-12-20

430

Sulfur-doped graphene via thermal exfoliation of graphite oxide in H2S, SO2, or CS2 gas.  

PubMed

Doping of graphene with heteroatoms is an effective way to tailor its properties. Here we describe a simple and scalable method of doping graphene lattice with sulfur atoms during the thermal exfoliation process of graphite oxides. The graphite oxides were first prepared by Staudenmaier, Hofmann, and Hummers methods followed by treatments in hydrogen sulfide, sulfur dioxide, or carbon disulfide. The doped materials were characterized by scanning electron microscopy, high-resolution X-ray photoelectron spectroscopy, combustible elemental analysis, and Raman spectroscopy. The ?-potential and conductivity of sulfur-doped graphenes were also investigated in this paper. It was found that the level of doping is more dramatically influenced by the type of graphite oxide used rather than the type of sulfur-containing gas used during exfoliation. Resulting sulfur-doped graphenes act as metal-free electrocatalysts for an oxygen reduction reaction. PMID:23656223

Poh, Hwee Ling; Šimek, Petr; Sofer, Zden?k; Pumera, Martin

2013-06-25

431

Sulfur Speciation in Lunar and Terrestrial Apatite  

NASA Astrophysics Data System (ADS)

Apatite from 14072,16, 14053,61, and 14053,241 have S K? peak shifts consistent with incorporation of both sulfide and sulfate. Sulfur concentration is inversely correlated with the percentage of sulfide.

Boyce, J. W.; Ma, C.; Eiler, J. M.; Baker, M. B.; Liu, Y.; Stolper, E. M.; Taylor, L. A.

2012-03-01

432

The sulfur thermochemical cycle for hydrogen production  

NASA Astrophysics Data System (ADS)

Results of research on sulfur-cycle hydrogen production are presented. An H2S cycle using MoS2 as a catalyst is mentioned as showing promise for thermochemical water splitting, with an equilibrium reaction yield of 7%. Use of I or Pt as catalysts raised efficiencies to 16 and 12%, respectively, and further studies employing hybrid cycles with CO2-S and noble metals are reviewed. Thermal decomposition reactions with sulfuric acid are examined, noting a potential 30% thermal efficiency, and sulfur cycle research being undertaken at various industrial laboratories is outlined. It is noted that experiments with sulfuric acid salts for water electrolysis at Los Alamos will probably use solar collectors as a heat source.

Dokiya, M.

1981-07-01

433

Sulfur Dioxide: Its Role in Climate Change  

NSDL National Science Digital Library

In this problem-based learning activity, learners investigate impact of sulfur dioxide on the environment. Sulfur dioxide comes from both human activities and natural sources. Burning coal and other fossil fuels is the largest source of sulfur dioxide from human activities. Students have a choice of analyzing the impact of volcanoesâ emissions of sulfur dioxide on the environment; they can also investigate the idea of injecting sulfates into the atmosphere to counteract global warming. Instructions to access NASA data are provided along with additional resources and activities. This module was developed to be used in the Earth System Science Education Alliance (ESSEA) courses for middle and high school teachers and is also available to teachers to adapt for general classroom use.

434

Sulfur Hexafluoride Tracer Dispersion within Cherry Orchard  

E-print Network

Sulfur Hexafluoride Tracer Dispersion within Cherry Orchard Zeyuan Chen, S. Edburg, and B. Lamb the correspondence between tracer gas concentration and atmospheric stability. Within the Tukey Cherry Orchard, we

Collins, Gary S.

435

Effects of variation of dietary sulfur on movement of sulfur in sheep rumen  

SciTech Connect

Effects of variations in dietary sulfur on rumen sulfur dynamics were studied under steady state conditions. In the first experimental period, three sheep were given 33.3 g of a pelleted diet hourly containing 1.59 g sulfur/kg (low) and in the second period the sulfur content was increased to 3.21 g/kg (high) by the addition of sodium sulfate. The daily sulfur intake was 1.158 g on the low sulfur diet and .545 g of this passed from the rumen in protein, .614 g was calculated to be absorbed from the rumen as sulfide, and .052 g was estimated to be recycled to the rumen. For sheep with daily intakes of 2.317 g sulfur, 1.212 g passed from the rumen in protein, 1.078 g was absorbed from the rumen, and .093 g was estimated to be recycled. It was estimated that 127 and 165 g microbial protein were synthesized/kg organic matter truly digested in the rumen for low and high sulfur diets, respectively. A simple model using simultaneous equations was proposed to describe rumen sulfur metabolism.

Kandylis, K.; Bray, A.C.

1987-01-01

436

Biocatalytic removal of organic sulfur from coal  

SciTech Connect

The objective is to characterize more completely the biochemical ability of the bacterium, Rhodococcus rhodochrous IGTS8, to cleave carbon-sulfur bonds with emphasis on data that will allow the development of a practical coal biodesulfurization process. Another approach for increasing the desulfurization activity of the IGTS8 cultures is to produce strains genetically that have higher activity. The goal of this part of research is to achieve strain improvement by introducing a stronger promoter using genetic engineering techniques. The promoter regulates the transcription of the genes for the desulfurization enzymes, and a stronger promoter, would up-regulate the expression of these genes, resulting in cells with higher desulfurization activity. Promoter probe vectors are used to identify and isolate promoters from a DNA library of the experimental organism. The major accomplishments have been to obtain high biodesulfurization activity in nonaqueous, media, especially using freeze-dried cells, and to have isolated strong promoters from R. rhodochrous IGTS8 which will be used to engineer the organism to produce strains with higher biocatalytic activity.

Webster, D.A. [Illinois Inst. of Tech., Chicago, IL (United States); Kilbane, J.J. II [Institute of Gas Technology, Chicadgo, IL (United States)

1994-09-09