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1

Solvent-based process has very high H/sub 2/S/CO/sub 2/ selectivity  

SciTech Connect

The task of removing H/sub 2/S from gases containing large amounts of CO/sub 2/ is difficult because of the different characteristics of the two acids: CO/sub 2/ is an inert which is corrosive in wet streams. In addition to being corrosive, H/sub 2/S is highly toxic and remains toxic after combustion to SO/sub 2/. For these reasons, specifications for pipeline gas limit the CO/sub 2/ to maximum amounts ranging from 0.5 to 3.0 vol %, depending on the country, but limit H/sub 2/S to only 2 to 5 ppm. A process to selectively remove H/sub 2/S in the presence of CO/sub 2/ is slated for its first commercial tryout, offshore. It will remove H/sub 2/S to ppm levels from gas containing more than 45% CO/sub 2/. Existing processes for this separation may be classified into three main groups: oxidative, solvent, and tertiary amine. Oxidative processes are based on the air oxidation of H/sub 2/S to sulfur with the help of a compound which is easily oxidized by atmospheric oxygen and easily reduced by H/sub 2/S. The best liquid oxidative processes can achieve a residual H/sub 2/S content in treated gas of less than 1 ppm with complete selectivity towards CO/sub 2/. Of these, the best known are Giammarco Vetrocoke and Stretford. Acceptance, however, has been fairly limited due to their complexity. Furthermore, the Vetrocoke process utilizes arsenic compounds and Stretford vanadium compounds. Use of either of these materials could cause ecological problems. These processes also involve some side reactions, with the formation of higher oxidation grade sulfur compounds which must be eliminated. This extra step increases chemical loss. Investment costs are high and applications generally restricted to small plants.

Gazzi, L.; Rescalli, C.

1984-07-16

2

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

3

Sulfur dioxide removal process  

Microsoft Academic Search

A process is described for reducing the loss of sodium values in a system for removing sulfur dioxide from a gas by the use of an absorption-desorption cycle employing aqueous sodium sulfite as the essential absorption solution. Sodium sulfate and\\/or sodium thio-sulfate build-up in the system is avoided and the loss of sodium values reduced by subjecting sodium sulfate and\\/or

N. E. Nicholson; J. Scarlett

1978-01-01

4

Process for forming sulfuric acid  

DOEpatents

An improved electrode is disclosed for the anode in a sulfur cycle hydrogen generation process where sulfur dioxie is oxidized to form sulfuric acid at the anode. The active compound in the electrode is palladium, palladium oxide, an alloy of palladium, or a mixture thereof. The active compound may be deposited on a porous, stable, conductive substrate.

Lu, Wen-Tong P. (Upper St. Clair, PA)

1981-01-01

5

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

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

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

8

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

9

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

10

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...

11

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

12

Assessment of sulfur removal processes for advanced fuel cell systems  

NASA Astrophysics Data System (ADS)

The performance characteristics of potential sulfur removal processes were evaluated and four of these processes, the Selexol process, the Benfield process, the Sulfinol process, and the Rectisol process, were selected for detailed technical and economic comparison. The process designs were based on a consistent set of technical criteria for a grass roots facility with a capacity of 10,000 tons per day of Illinois No. 6 coal. Two raw gas compositions, based on oxygen blown and air blown Texaco gasification, were used. The bulk of the sulfur was removed in the sulfur removal unit, leaving a small amount of sulfur compounds in the gas. The remaining sulfur compounds were removed by reaction with zinc oxide in the sulfur polishing unit. The impact of COS hydrolysis pretreatment on sulfur removal was evaluated. Comprehensive capital and O and M cost estimates for each of the process schemes were developed.

Lorton, G. A.

1980-01-01

13

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

14

The Fate of Sulfur in Late-Stage Magmatic Processes: Insights From Quadruple Sulfur Isotopes  

Microsoft Academic Search

Multiple sulfur isotopes (32S, 33S, 34S and 36S) have recently been shown to be useful tracers of fluid-rock interaction in seafloor hydrothermal systems [1]. Here we present the application of multiple sulfur isotopes to subaerial volcanoes with the aim of unraveling the various processes fractionating sulfur in the upper volcanic system. We take advantage of the fact that the ascent

N. S. Keller; S. Ono; A. M. Shaw

2009-01-01

15

Process for the separation of sulfur oxides from a gaseous mixture containing sulfur oxides and oxygen  

SciTech Connect

An improved process for the separation of sulfur oxides from a gaseous mixture containing sulfur oxides and oxygen is disclosed. The gaseous mixture is contacted with a solid sulfur oxide acceptor comprising copper, copper oxide, or a mixture thereof dispersed on a carrier material in combination with a platinum group metal component and a component selected from the group consisting of rhenium, germanium and tin.

Derosset, A.J.; Ginger, E.A.

1980-12-23

16

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

17

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.

18

Process for removal of sulfur dioxide from gas streams  

Microsoft Academic Search

An improved apparatus and process are disclosed for the removal of sulfur oxides such as sulfur dioxide from waste gas streams. The process comprises scrubbing the waste gas with a circulating aqueous sodium sulfite\\/sodium bisulfite absorption solution at a relatively low ph followed by subjecting a portion of the circulating absorption solution to an improved multi-stage regeneration procedure wherein lime

Pike

1982-01-01

19

Elemental sulfur from regenerable FGD and IGCC processes  

SciTech Connect

Gas streams containing concentrated levels of SO{sub 2} are common in many regenerable flue-gas desulfurization (FGD) processes, in gas-treatment systems associated with coal gasification processes, and in hydrocarbon treatment processes. Generally, the most desirable sulfur by-product is elemental sulfur. In the past, a modified Claus process was usually the method employed to convert SO{sub 2} to elemental sulfur. The Claus process, however, involves multiple reactors in series, is relatively expensive, consumes significant energy, and does not go to completion, which means that a tail gas treatment plant and other facilities are required. For over five years, Sorbent Technologies corporation has been developing and scaling up a simpler, less-costly process for converting SO{sub 2}-rich gases directly to elemental sulfur. The process is based on a new SO{sub 2}-to-elemental sulfur catalyst. The simple technology operates at typical coal gasification temperatures and can use natural gas (reformed methane) or other typical process gases for SO{sub 2} reduction. This new direct-to-sulfur process was recently tested at the Federal Energy Technology Center's advanced Copper Oxide Process FGD pilot plant in Pittsburgh, A skid-mounted test unit was placed after the copper oxide regenerator, where it turned the high-concentration SO{sub 2} off-gas directly into elemental sulfur. This paper discusses the chemistry involved in the new technology, traces its development, and presents the results achieved in various pilot plant tests.

Nelson, S.G.; Oehlberg, R.J.; Cianciolo, B.C.

1998-07-01

20

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

21

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

22

Assessment of sulfur removal processes for advanced fuel cell systems  

Microsoft Academic Search

The performance characteristics of potential sulfur removal processes were evaluated and four of these processes, the Selexol process, the Benfield process, the Sulfinol process, and the Rectisol process, were selected for detailed technical and economic comparison. The process designs were based on a consistent set of technical criteria for a grass roots facility with a capacity of 10,000 tons per

G. A. Lorton

1980-01-01

23

Coupled Oxygen and Sulfur Isotope Investigations of Bacterial Sulfate Reduction Reveal Sulfur Cycling Processes in Deep Sea Sediments  

Microsoft Academic Search

Decades of research on sulfur and oxygen isotope effects associated with the process of microbial sulfate reduction, have led to an improved understanding of the factors influencing sulfur and oxygen composition of sulfate during its reduction to sulfide. There is a general consensus that kinetic fractionation processes control sulfur isotope fractionation, but the causes for the large variability of fractionation

S. M. Bernasconi; U. G. Wortmann; M. E. Boettcher; B. Brunner

2006-01-01

24

Assessment of sulfur removal processes for advanced fuel cell systems  

SciTech Connect

This study consisted of a technical evaluation and economic comparison of sulfur removal processes for integration into a coal gasification-molten carbonate (CGMC) fuel cell power plant. Initially, the performance characteristics of potential sulfur removal processes were evaluated and screened for conformance to the conditions and requirements expected in commercial CGMC power plants. Four of these processes, the Selexol process, the Benfield process, the Sulfinol process, and the Rectisol process, were selected for detailed technical and economic comparison. The process designs were based on a consistent set of technical criteria for a grass roots facility with a capacity of 10,000 tons per day of Illinois No. 6 coal. Two raw gas compositions, based on oxygen-blown and air-blown Texaco gasification, were used. The bulk of the sulfur was removed in the sulfur removal unit, leaving a small amount of sulfur compounds in the gas (1 ppMv or 25 ppMv). The remaining sulfur compounds were removed by reaction with zinc oxide in the sulfur polishing unit. The impact of COS hydrolysis pretreatment on sulfur removal was evaluated. Comprehensive capital and O and M cost estimates for each of the process schemes were developed for the essentially complete removal of sulfur compounds. The impact on the overall plant performance was also determined. The total capital requirement for sulfur removal schemes ranged from $59.4/kW to $84.8/kW for the oxygen-blown cases and from $89.5/kW to $133/kW for the air-blown cases. The O and M costs for sulfur removal for 70% plant capacity factor ranged from 0.82 mills/kWh to 2.76 mills/kWh for the oxygen-blown cases and from 1.77 mills/kWh to 4.88 mills/kWh for the air-blown cases. The Selexol process benefitted the most from the addition of COS hydrolysis pretreatment.

Lorton, G.A.

1980-01-01

25

Elemental sulfur from regenerable FGD and IGCC processes  

SciTech Connect

Gas streams containing concentrated levels of SO{sub 2} are common in many regenerable flue-gas desulfurization (FGD) processes, in gas-treatment systems associated with coal gasification processes, and in hydrocarbon treatment processes. Generally, the most desirable sulfur by-product is elemental sulfur. In the past, a modified Claus process was usually the method employed to convert SO{sub 2} to elemental sulfur. The Claus process, however, involves multiple reactors in series, is relatively expensive, consumes significant energy, and does not go to completion, which means that a tail gas treatment plant and other facilities are required. For over five years, Sorbent Technologies Corporation has been developing and scaling up a simpler, less-costly process for converting SO{sub 2}-rich gases directly to elemental sulfur. The process is based on a new SO{sub 2}-to-elemental sulfur catalyst. The simple technology operates at typical coal gasification temperatures and can use natural gas (reformed methane) or other typical process gases for SO{sub 2} reduction. This new direct-to-sulfur process was recently tested at the Federal Energy Technology Center`s advanced Copper Oxide Process FGD pilot plant in Pittsburgh. A skid-mounted test unit was placed after the copper oxide regenerator, where it turned the high-concentration SO{sub 2} off-gas directly into elemental sulfur. This paper discusses the chemistry involved in the new technology, traces its development, and presents the results achieved in various pilot plant tests.

Nelson, S.G.; Oehlberg, R.J.; Cianciolo, B.C.

1998-04-01

26

The Fate of Sulfur in Late-Stage Magmatic Processes: Insights From Quadruple Sulfur Isotopes  

NASA Astrophysics Data System (ADS)

Multiple sulfur isotopes (32S, 33S, 34S and 36S) have recently been shown to be useful tracers of fluid-rock interaction in seafloor hydrothermal systems [1]. Here we present the application of multiple sulfur isotopes to subaerial volcanoes with the aim of unraveling the various processes fractionating sulfur in the upper volcanic system. We take advantage of the fact that the ascent of volcanic gases through a hydrothermal system causes complex isotopic fractionation between the quaduple sulfur isotopes. ?34S is thought to trace the source of sulfur as well as magma degassing; at equilibrium, ?33S follows a mass-dependent fractionation relationship such that two phases in equilibrium with each other have equal ?33S values (?33S ? ln(?33S+1) - 0.515×ln(?34S+1)). Disequilibrium ?33S values can indicate isotope mixing and other fluid-rock interactions. The ultimate aim of this study is to assess the use of quadruple sulfur isotopes to obtain quantitative information on the sulfur cycle at convergent plate margins. The sulfur mass balance at convergent margins is poorly constrained, partly because late-stage processes are challenging to quantify and lead to large uncertainties in the global output fluxes. Quadruple sulfur isotopes provide a powerful tool to untangle the convoluted history of volcanic systems. Here we report the first quadruple sulfur isotopic values for H2S, SO2 and native sulfur from arc volcanoes. Fumarolic gases (˜100°C) and sulfur sublimates were collected from Poas and Turrialba, two actively degassing volcanoes in Costa Rica. The gases were bubbled in situ through chemical traps to separate H2S from SO2: H2S was reacted to form ZnS, and SO2 to form BaSO4. Sulfur was chemically extracted from the solid phases and precipitated as Ag2S, which was fluorinated to SF6 and analysed by IRMS. Poas and Turrialba have H2S/SO2 ˜1 and 0.01, respectively. ?34SH2S and ?34SSO2 are similar to gases measured at other arcs [2], - 7.9‰ and 0.6‰ for Poas, and -8.5‰ and +9‰ for Turrialba, likely reflecting a mixture of mantle (?34S = 0‰) and slab sources which have been degassed to variable degrees. Sulfur sublimate values are similar to those for H2S. ?33S values are different within each H2S/SO2 pair (?33SH2S and ?33SSO2 are -0.01‰ and -0.02‰ for Poas, 0‰ and -0.07‰ for Turrialba), indicating that at Turrialba, the two gas species are not in isotopic equilibrium. Reaction of the gases with mineral phases, such as sulfur-bearing alteration products in the volcanic edifice (e.g., alunite, anhydrite, sulfides) may explain these differences. [1] Ono et al. (2007), GCA 70 1170-1182, [2] Taylor (1986), RiM 16 185-225

Keller, N. S.; Ono, S.; Shaw, A. M.

2009-05-01

27

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

28

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This second quarter report of 2003 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 off-shore applications. CrystaSulf{reg_sign} (service mark of CrystaTech, Inc.) 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. Previous reports described development of a catalyst with the required selectivity and efficiency for producing sulfur dioxide from H{sub 2}S. In the laboratory, the catalyst was shown to be robust and stable in the presence of several intentionally added contaminants, including condensate from the pilot plant site. Bench-scale catalyst testing at the CrystaSulf pilot plant using the actual pilot plant gas was successful, and a skid-mounted catalyst pilot unit has been designed for fabrication and testing at the CrystaSulf pilot site.

Dennis Dalrymple

2003-07-01

29

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

30

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

31

Assessment of hidden sulfur cycling processes through modeling of sulfur and oxygen isotope signatures of pore-water sulfate  

NASA Astrophysics Data System (ADS)

We developed a numerical model to simulate/predict the sulfur and oxygen isotope composition of pore-water sulfate in sediment pore-water profiles where sulfate concentrations decrease linearly with depth, presumably under steady-state conditions. We considered the effects of sulfate consumption due to the anaerobic oxidation of methane (AOM) alone and in combination with organoclastic sulfate reduction Linear sulfate concentration profiles are commonly associated with sulfate loss at depth driven by sulfate reduction coupled to AOM presumably under steady-state conditions. During this reaction the net consumption of sulfate and methane are balanced. The general assumption is that under steady-state conditions there is little to no sulfate loss due to organoclastic sulfate reduction and negligible sulfate gain due to other sulfur cycling processes above the sulfate-methane transition zone (SMTZ). When model results are compared to pore-water sulfate data from sediment cores obtained from the Argentine Basin, we see that sulfate reduction coupled to AOM alone cannot produce the measured sulfur and oxygen isotope patterns. Modeled isotope profiles including organoclastic sulfate reduction above the SMTZ provide a good match to the observations. The model comparison to our data reveals large sulfur isotope fractionation effects, with sulfur isotope enrichment factors (?34S) exceeding 50‰, consistent with the observed sulfur isotope offset between sulfate and sulfide. Furthermore, our model requires oxygen isotope exchange factors (?O) equal to or exceeding 10. Linear sulfate concentration profiles do not readily reveal the complexity and richness of sulfur cycling processes above the SMTZ and are able to 'hide' the effects of organoclastic sulfate reduction and additional sulfur cycling. Hence, the use of combined sulfur and oxygen isotope analysis is a valuable tool that can be used to gain insight into sulfur cycling not revealed by traditional means.

Arnold, G. L.; Liu, B.; Henkel, S.; Sawicka, J.; Kasten, S.; Khalili, A.; Brunner, B.

2012-12-01

32

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

33

Low Quality Natural Gas Sulfur Removal and Recovery CNG Claus Sulfur Recovery Process  

SciTech Connect

Increased use of natural gas (methane) in the domestic energy market will force the development of large non-producing gas reserves now considered to be low quality. Large reserves of low quality natural gas (LQNG) contaminated with hydrogen sulfide (H{sub 2}S), carbon dioxide (CO{sub 2}) and nitrogen (N) are available but not suitable for treatment using current conventional gas treating methods due to economic and environmental constraints. A group of three technologies have been integrated to allow for processing of these LQNG reserves; the Controlled Freeze Zone (CFZ) process for hydrocarbon / acid gas separation; the Triple Point Crystallizer (TPC) process for H{sub 2}S / C0{sub 2} separation and the CNG Claus process for recovery of elemental sulfur from H{sub 2}S. The combined CFZ/TPC/CNG Claus group of processes is one program aimed at developing an alternative gas treating technology which is both economically and environmentally suitable for developing these low quality natural gas reserves. The CFZ/TPC/CNG Claus process is capable of treating low quality natural gas containing >10% C0{sub 2} and measurable levels of H{sub 2}S and N{sub 2} to pipeline specifications. The integrated CFZ / CNG Claus Process or the stand-alone CNG Claus Process has a number of attractive features for treating LQNG. The processes are capable of treating raw gas with a variety of trace contaminant components. The processes can also accommodate large changes in raw gas composition and flow rates. The combined processes are capable of achieving virtually undetectable levels of H{sub 2}S and significantly less than 2% CO in the product methane. The separation processes operate at pressure and deliver a high pressure (ca. 100 psia) acid gas (H{sub 2}S) stream for processing in the CNG Claus unit. This allows for substantial reductions in plant vessel size as compared to conventional Claus / Tail gas treating technologies. A close integration of the components of the CNG Claus process also allow for use of the methane/H{sub 2}S separation unit as a Claus tail gas treating unit by recycling the CNG Claus tail gas stream. This allows for virtually 100 percent sulfur recovery efficiency (virtually zero SO{sub 2} emissions) by recycling the sulfur laden tail gas to extinction. The use of the tail gas recycle scheme also deemphasizes the conventional requirement in Claus units to have high unit conversion efficiency and thereby make the operation much less affected by process upsets and feed gas composition changes. The development of these technologies has been ongoing for many years and both the CFZ and the TPC processes have been demonstrated at large pilot plant scales. On the other hand, prior to this project, the CNG Claus process had not been proven at any scale. Therefore, the primary objective of this portion of the program was to design, build and operate a pilot scale CNG Claus unit and demonstrate the required fundamental reaction chemistry and also demonstrate the viability of a reasonably sized working unit.

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

1997-10-01

34

Process for combusting solid sulfur-containing material  

SciTech Connect

In a process for combusting solid, sulfur-containing material by contacting the material with gaseous oxygen in a combustion zone at combustion conditions to produce combustion products including at least one sulfur oxide, the improvement is described comprising carrying out the contacting in the presence of discrete particles containing a metal-containing spinel. This reduces the amount of sulfur oxide emitted from the combustion zone. The metal containing spinel includes a first metal and at least two different second metals having valences higher than the valence of the first metal. One of the second metals being aluminum and the other of the second metals being trivalent and selected from the group consisting of iron, chromium, vanadium, manganese, gallium, boron, cobalt and mixture thereof. The atomic ratio of the first metal to the second metals in the spinel is at least about 0.17 and the spinel has a surface area in the range of about 25 m/sup 2//gm to about 600 m/sup 2//gm.

Yoo, J.S.; Jaecker, J.A.

1988-07-19

35

Process and system for removing sulfur from sulfur-containing gaseous streams  

DOEpatents

A multi-stage UCSRP process and system for removal of sulfur from a gaseous stream in which the gaseous stream, which contains a first amount of H.sub.2S, is provided to a first stage UCSRP reactor vessel operating in an excess SO.sub.2 mode at a first amount of SO.sub.2, producing an effluent gas having a reduced amount of SO.sub.2, and in which the effluent gas is provided to a second stage UCSRP reactor vessel operating in an excess H.sub.2S mode, producing a product gas having an amount of H.sub.2S less than said first amount of H.sub.2S.

Basu, Arunabha (Aurora, IL); Meyer, Howard S. (Hoffman Estates, IL); Lynn, Scott (Pleasant Hill, CA); Leppin, Dennis (Chicago, IL); Wangerow, James R. (Medinah, IL)

2012-08-14

36

Test of TDA's Direct Oxidation Process for Sulfur Recovery  

SciTech Connect

This project was a Phase III pilot plant test of TDA's gas sweetening process done under realistic conditions. TDA Research Inc successfully completed the test at Whiting Petroleum's Sable San Andreas Gas Plant. The feed was approximately 228,000 standard cubic feet per day (SCFD) of gas that contained approximately 60 vol% CO{sub 2}, 20 vol% CH{sub 4} and 10 vol% C{sub 3}+ and higher hydrocarbons. The feed was associated gas from CO{sub 2} flooding operations carried out on Whiting's oil wells. The gas is collected and piped to the Sable gas plant where it is normally flared. We sited our pilot plant in line with the flare so that we could remove the hydrogen sulfide (H{sub 2}S) prior to flaring. The average H{sub 2}S concentration in the gas during the field test was 7341 ppm. The selectivity of our process for converting H{sub 2}S into elemental sulfur was essentially 100% and the catalyst converted 90% of the H{sub 2}S into sulfur and water (the remaining 10% of the H{sub 2}S passed through unconverted). Importantly, no catalyst deactivation was observed for over the course of the 1000+ hour test. Minimal (ca. 10-15 ppm) of SO{sub 2} was formed during the test. Approximately 3.6 tons of elemental sulfur was recovered from a total inlet of 3.9 tons of sulfur (as H{sub 2}S). The total amount of SO{sub 2} released from the plant (taking into account flaring of the unconverted 10% H2S) was 0.86 tons. This amount of SO{sub 2} is much lower than the normal 8 tons that would have been emitted if all of the H{sub 2}S were flared over the time of the pilot plant test. The pilot plant was simple to operate and required much less operator intervention than is typical for a new unit being commissioned. Our operator (Mr. Eugene Peeples) has more than 30 years of experience operating commercial scale liquid redox sulfur recovery processes and in his opinion, TDA's Direct Oxidation pilot plant is easier to operate than liquid systems. The ease of use and low capital and operating costs of TDA's Direct Oxidation process makes it an attractive technology to be used where traditional sulfur recovery technologies are too expensive (e.g. small to medium sized plants). Currently, TDA's direct oxidation process has been exclusively licensed to SulfaTreat, and is being offered commercially under the trade name SulfaTreat-DO{reg_sign}. We anticipate that the first plant will be installed in 2005.

Girish Srinivas; Steven C. Gebhard; Eugene Peeples; Sandra Huzyk; Randy Welch

2005-01-01

37

SULFURIC ACID REMOVAL PROCESS EVALUATION: SHORT-TERM RESULTS  

SciTech Connect

The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. Sulfuric acid controls are becoming of increasing interest to utilities with coal-fired units for a number of reasons. Sulfuric acid is a Toxic Release Inventory species, a precursor to acid aerosol/condensable emissions, and can cause a variety of plant operation problems such as air heater plugging and fouling, back-end corrosion, and plume opacity. These issues will likely be exacerbated with the retrofit of SCR for NO{sub x} control on some coal-fired plants, as SCR catalysts are known to further oxidize a portion of the flue gas SO{sub 2} to SO{sub 3}. The project is testing the effectiveness of furnace injection of four different calcium- and/or magnesium-based alkaline sorbents on full-scale utility boilers. These reagents have been tested during four one- to two-week tests conducted on two First Energy Bruce Mansfield Plant units. One of the sorbents tested was a magnesium hydroxide slurry produced from a wet flue gas desulfurization system waste stream, from a system that employs a Thiosorbic{reg_sign} Lime scrubbing process. The other three sorbents are available commercially and include dolomite, pressure-hydrated dolomitic lime, and commercial magnesium hydroxide. The dolomite reagent was injected as a dry powder through out-of-service burners, while the other three reagents were injected as slurries through air-atomizing nozzles into the front wall of upper furnace, either across from the nose of the furnace or across from the pendant superheater tubes. After completing the four one- to two-week tests, the most promising sorbents were selected for longer-term (approximately 25-day) full-scale tests. The longer-term tests are being conducted to confirm the effectiveness of the sorbents tested over extended operation and to determine balance-of-plant impacts. This reports presents the results of the short-term tests; the long-term test results will be reported in a later document. The short-term test results showed that three of the four reagents tested, dolomite powder, commercial magnesium hydroxide slurry, and byproduct magnesium hydroxide slurry, were able to achieve 90% or greater removal of sulfuric acid compared to baseline levels. The molar ratio of alkali to flue gas sulfuric acid content (under baseline conditions) required to achieve 90% sulfuric acid removal was lowest for the byproduct magnesium hydroxide slurry. However, this result may be confounded because this was the only one of the three slurries tested with injection near the top of the furnace across from the pendant superheater platens. Injection at the higher level was demonstrated to be advantageous for this reagent over injection lower in the furnace, where the other slurries were tested.

Gary M. Blythe; Richard McMillan

2002-02-04

38

SULFURIC ACID REMOVAL PROCESS EVALUATION: SHORT-TERM RESULTS  

SciTech Connect

The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. Sulfuric acid controls are becoming of increasing interest to utilities with coal-fired units for a number of reasons. Sulfuric acid is a Toxic Release Inventory species, a precursor to acid aerosol/condensable emissions, and can cause a variety of plant operation problems such as air heater plugging and fouling, back-end corrosion, and plume opacity. These issues will likely be exacerbated with the retrofit of SCR for NOX control on some coal-fired plants, as SCR catalysts are known to further oxidize a portion of the flue gas SO{sub 2} to SO{sub 3}. The project is testing the effectiveness of furnace injection of four different calcium- and/or magnesium-based alkaline sorbents on full-scale utility boilers. These reagents have been tested during four one- to two-week tests conducted on two FirstEnergy Bruce Mansfield Plant units. One of the sorbents tested was a magnesium hydroxide slurry produced from a wet flue gas desulfurization system waste stream, from a system that employs a Thiosorbic{reg_sign} Lime scrubbing process. The other three sorbents are available commercially and include dolomite, pressure-hydrated dolomitic lime, and commercial magnesium hydroxide. The dolomite reagent was injected as a dry powder through out-of-service burners, while the other three reagents were injected as slurries through air-atomizing nozzles into the front wall of upper furnace, either across from the nose of the furnace or across from the pendant superheater tubes. After completing the four one- to two-week tests, the most promising sorbents were selected for longer-term (approximately 25-day) full-scale tests. The longer-term tests are being conducted to confirm the effectiveness of the sorbents tested over extended operation and to determine balance-of-plant impacts. This reports presents the results of the short-term tests; the long-term test results will be reported in a later document. The short-term test results showed that three of the four reagents tested, dolomite powder, commercial magnesium hydroxide slurry, and byproduct magnesium hydroxide slurry, were able to achieve 90% or greater removal of sulfuric acid compared to baseline levels. The molar ratio of alkali to flue gas sulfuric acid content (under baseline conditions) required to achieve 90% sulfuric acid removal was lowest for the byproduct magnesium hydroxide slurry. However, this result may be confounded because this was the only one of the three slurries tested with injection near the top of the furnace across from the pendant superheater platens. Injection at the higher level was demonstrated to be advantageous for this reagent over injection lower in the furnace, where the other slurries were tested.

Gary M. Blythe; Richard McMillan

2002-03-04

39

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

40

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

41

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

42

Using stable isotopes to monitor forms of sulfur during desulfurization processes: A quick screening method  

USGS Publications Warehouse

A method using stable isotope ratio analysis to monitor the reactivity of sulfur forms in coal during thermal and chemical desulfurization processes has been developed at the Illinois State Geological Survey. The method is based upon the fact that a significant difference exists in some coals between the 34S/32S ratios of the pyritic and organic sulfur. A screening method for determining the suitability of coal samples for use in isotope ratio analysis is described. Making these special coals available from coal sample programs would assist research groups in sorting out the complex sulfur chemistry which accompanies thermal and chemical processing of high sulfur coals. ?? 1987.

Liu, C.-L.; Hackley, K.C.; Coleman, D.D.; Kruse, C.W.

1987-01-01

43

Nitrate removal with sulfur-limestone autotrophic denitrification processes  

SciTech Connect

Nitrate removal using sulfur and limestone autotrophic denitrification (SLAD) processes was evaluated with four laboratory-scale fixed-bed column reactors. The research objectives were (1) to determine the optimum design criteria of the fixed-bed SLAD columns; and (2) to evaluate the effects of biofouling on the SLAD column performance. A maximum denitrification rate of 384 g NO{sub 3}{sup {minus}}-N(m{sup 3}{center_dot}day) was achieved at a loading rate between 600 and 700 g NO{sub 3}{sup {minus}}-N(m{sup 3}{center_dot}day). The effluent nitrite concentration started to rise gradually once the loading rate was above 600 g NO{sub 3}{sup {minus}}-N(m{sup 3}{center_dot}day). A loading rate between 175 and 225 g NO{sub 3}{sup {minus}}-N(m{sup 3}{center_dot}day) achieved the maximum nitrate-N removal efficiency ({approximately}95%). Biofouling was evaluated based on tracer studies, the measured biofilm thickness, and modeling. The porosities of the columns fluctuated with time, and the elongation of the filter media was observed. Biofouling caused short-circuiting and decreased nitrate removal efficiency. A SLAD column will require backwashing after 6 months of operation when the influent is synthetic ground water but will foul and require backwashing within 1--2 months when the influent is real ground water.

Flere, J.M.; Zhang, T.C. [Univ. of Nebraska, Omaha, NE (United States). Dept. of Civil Engineering] [Univ. of Nebraska, Omaha, NE (United States). Dept. of Civil Engineering

1999-08-01

44

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...

45

SH radical: the key intermediate in sulfur transformation during thermal processing of coal  

SciTech Connect

To uncouple the complex behavior of sulfur transformation during thermal processing of coal and to elucidate the main mechanism, typical organic and inorganic sulfur compounds impregnated on or mixed with a low-ash char are studied through temperature-programmed decomposition coupled with online mass spectrum analysis (TPD-MS) and followed by temperature-programmed oxidation coupled also with online mass spectrum analysis (TPO-MS) in a temperature range of up to 800{sup o}C. It is evident that the cleavages of C{sub al}-S and C{sub ar}-S bonds, where the subscripts al and ar stand for aliphatic and aromatic carbon, respectively, in the organic compounds result in the formation of SH radicals, which then undergo secondary reactions with the char to form various sulfur compounds such as H{sub 2}S, SO{sub 2}, COS, and elemental sulfur, as well as sulfur structures in the char. H{sub 2} has the ability to stabilize the SH radicals and weaken the interactions between the SH radicals and the char. For the sulfur compounds, which do not generate the SH radical, the only sulfur products detected are those formed directly from the decomposition of the starting sulfur compounds, H{sub 2}S from FeS{sub 2} in H{sub 2} or SO{sub 2} from Fe{sub 2}(SO{sub 4}){sub 3} in He, for example, and no sulfur structure is formed in the char. Minerals have significant effects on the bond cleavage temperature and the reactions of the SH radicals with the char. It is clear that the SH radical is a key species interacting with the char to form secondary sulfur compounds, while H{sub 2}S and SO{sub 2} play no role in the sulfur transformation to the carbon structure. 34 refs., 12 figs., 1 tab.

Jinding Yan; Jianli Yang; Zhenyu Liu [Chinese Academy of Sciences, Taiyuan (China). State Key Laboratory of Coal Conversion, Institute of Coal Chemistry

2005-07-01

46

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

47

Investigation of 2 liquid phase separation characteristics on the iodine–sulfur thermochemical hydrogen production process  

Microsoft Academic Search

Separation characteristics of 2 liquid phase, sulfuric acid phase and poly-hydriodic acid phase, in HI-H2SO4-I2 solution of the iodine–sulfur (IS) thermochemical hydrogen production process were measured in the wide operation temperature range, from 273 to 368 K in order to establish the closed-cycle operation technology and to improve thermal efficiency of the process. The effects of solution temperature and composition of

M Sakurai; H Nakajima; K Onuki; S Shimizu

2000-01-01

48

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

49

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

50

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

51

SULFURIC ACID REMOVAL PROCESS EVALUATION: LONG-TERM RESULTS  

SciTech Connect

The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory, under Cooperative Agreement DE-FC26-99FT40718, along with EPRI, the American Electric Power Company (AEP), FirstEnergy Corp., the Tennessee Valley Authority, and Dravo Lime, Inc. Sulfuric acid controls are becoming of increasing interest to power generators with coal-fired units for a number of reasons. Sulfuric acid is a Toxic Release Inventory species and can cause a variety of plant operation problems such as air heater plugging and fouling, back-end corrosion, and plume opacity. These issues will likely be exacerbated with the retrofit of selective catalytic reduction (SCR) for NO{sub x} control on many coal-fired plants, as SCR catalysts are known to further oxidize a portion of the flue gas SO{sub 2} to SO{sub 3}. The project previously tested the effectiveness of furnace injection of four different calcium-and/or magnesium-based alkaline sorbents on full-scale utility boilers. These reagents were tested during four one- to two-week tests conducted on two FirstEnergy Bruce Mansfield Plant (BMP) units. One of the sorbents tested was a magnesium hydroxide byproduct slurry produced from a modified Thiosorbic{reg_sign} Lime wet flue gas desulfurization system. The other three sorbents are available commercially and include dolomite, pressure-hydrated dolomitic lime, and commercial magnesium hydroxide. The dolomite reagent was injected as a dry powder through out-of-service burners, while the other three reagents were injected as slurries through air-atomizing nozzles inserted through the front wall of the upper furnace, either across from the nose of the furnace or across from the pendant superheater tubes. After completing the four one- to two-week tests, the most promising sorbents were selected for longer-term (approximately 25-day) full-scale tests on two different units. The longer-term tests were conducted to confirm the effectiveness of the sorbents tested over extended operation on two different boilers, and to determine balance-of-plant impacts. The first long-term test was conducted on FirstEnergy's BMP, Unit 3, and the second test was conducted on AEP's Gavin Plant, Unit 1. The Gavin Plant testing provided an opportunity to evaluate the effects of sorbent injected into the furnace on SO{sub 3} formed across an operating SCR reactor. This report presents the results from those long-term tests. The tests determined the effectiveness of injecting commercially available magnesium hydroxide slurry (Gavin Plant) and byproduct magnesium hydroxide slurry (both Gavin Plant and BMP) for sulfuric acid control. The results show that injecting either slurry could achieve up to 70 to 75% overall sulfuric acid removal. At BMP, this overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NOX control than at removing SO{sub 3} formed in the furnace. The long-term tests also determined balance-of-plant impacts from slurry injection during the two tests. These include impacts on boiler back-end temperatures and pressure drops, SCR catalyst properties, ESP performance, removal of other flue gas species, and flue gas opacity. For the most part the balance-of-plant impacts were neutral to positive, although adverse effects on ESP performance became an issue during the BMP test.

Gary M. Blythe; Richard McMillan

2002-07-03

52

Sulfur Fumigation Processing of Traditional Chinese Medicinal Herbs: Beneficial or Detrimental?  

PubMed Central

Majority of traditional Chinese medicine (TCM) herbs need to undergo post-harvesting processing to convert raw material into the form readily used for prescription. In general, processing procedures are either according to China Pharmacopeia or based on traditional methods. Recently sulfur fumigation is increasingly used to replace traditional sun-drying for its pesticidal and anti-bacterial properties in a cheap and convenient manner. However, to date information on effects of sulfur fumigation on herbal safety and efficacy are limited. This article addresses potential destructive effects of sulfur fumigation on herbal efficacy and safety through reviewing currently available information. Since recently increased numbers of studies have demonstrated that sulfur fumigation-induced dramatic changes in chemical profiles of various sulfur-fumigated herbs, consequent alteration of efficacy, and/or potential incidence of toxicity are suspected. Therefore comprehensive investigations on effects of sulfur fumigation on toxicity, chemical profiles, pharmacokinetics, and bioactivities of TCM herbs are timely to provide scientific basis for standardization and regulation of this currently common but potentially harmful processing method. PMID:22207851

Kan, Winnie Lai Ting; Ma, Bin; Lin, Ge

2011-01-01

53

The East Penn process for recycling sulfuric acid from lead-acid batteries  

SciTech Connect

Prior to March 1992, the only component of the lead-acid battery that was not recycled by East Penn Manufacturing Company was the sulfuric acid electrolyte. This acid was unusable in new batteries because the iron level was found to exceed new product specifications. The development of a liquid ion exchange process to remove the iron from the acid allows East Penn to currently recover over three million gallons of sulfuric acid annually. The process is based upon the use of an iron selective liquid ion exchange material or solvent to extract iron from the sulfuric acid electrolyte followed by regeneration of the solvent. Equilibrium and kinetic data for the extraction and regeneration steps were collected in order to scale up the process to commercial scale. An electrochemical process for the treatment of the acid used in the regeneration step was also developed which significantly reduces the volume of strip acid required in the process.

Leiby, R.; Bricker, M. [East Penn Manufacturing Co., Inc., Lyon Station, PA (United States); Spitz, R. [Spitz (R.), Holbrook, MA (United States)

1995-12-31

54

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

55

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

56

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

57

A sulfuric-lactic acid process for efficient purification of fungal chitosan with intact molecular weight.  

PubMed

The most recent method of fungal chitosan purification, i.e., two steps of dilute sulfuric acid treatment, pretreatment of cell wall at room temperature for phosphate removal and extraction of chitosan from the phosphate free cell wall at high temperature, significantly reduces the chitosan molecular weight. This study was aimed at improvement of this method. In the pretreatment step, to choose the best conditions, cell wall of Rhizopus oryzae, containing 9% phosphate, 10% glucosamine, and 21% N-acetyl glucosamine, was treated with sulfuric, lactic, acetic, nitric, or hydrochloric acid, at room temperature. Sulfuric acid showed the best performance in phosphate removal (90%) and cell wall recovery (89%). To avoid depolymerisation of chitosan, hot sulfuric acid extraction was replaced with lactic acid treatment at room temperature, and a pure fungal chitosan was obtained (0.12 g/g cell wall). Similar pretreatment and extraction processes were conducted on pure shrimp chitosan and resulted in a chitosan recovery of higher than 87% while the reduction of chitosan viscosity was less than 15%. Therefore, the sulfuric-lactic acid method purified the fungal chitosan without significant molecular weight manipulation. PMID:24211428

Naghdi, Mitra; Zamani, Akram; Karimi, Keikhosro

2014-02-01

58

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...

59

Using Mars's Sulfur Cycle to Constrain the Duration and Timing of Fluvial Processes  

NASA Technical Reports Server (NTRS)

Sulfur exists in high abundances at diverse locations on Mars. This work uses knowledge of the Martian sulfate system to discriminate between leading hypotheses and discusses the implications for duration and timing of fluvial processes. Additional information is contained in the original extended abstract.

Blaney, D. L.

2002-01-01

60

Desulfurization of organic sulfur from lignite by an electron transfer process  

SciTech Connect

This study is an attempt to desulfurize organic sulfur from lignite samples with ferrocyanide ion as the electron transferring agent. Effect of temperature, particle size and concentration of ferrocyanide ion on desulfurization from the lignite samples has been investigated. The desulfurization process has been found to be continuous and gradually increases with increase of temperature from 298 to 368 K. The particle size has no significant impact on sulfur removal from the lignite samples. Particle size has no profound impact on the amount of sulfur removal. The desulfurization reaction has been found to be dependent on the concentration of potassium ferrocyanide. Gradual increase in the concentration of potassium ferrocyanide raised the magnitude of desulfurization, but at a higher concentration, the variation is not significant.

Demirbas, A. [Selcuk University, Konya (Turkey). Dept. for Chemical Engineering

2006-10-15

61

The GA sulfur-iodine water-splitting process - A status report  

NASA Technical Reports Server (NTRS)

The development of a sulfur-iodine thermal water splitting cycle is described. The process features a 50% thermal efficiency, plus all liquid and gas handling. Basic chemical investigations comprised the development of multitemperature and multistage sulfuric acid boost reactors, defining the phase behavior of the HI/I2/H2O/H3PO4 mixtures, and development of a decomposition process for hydrogen iodide in the liquid phase. Initial process engineering studies have led to a 47% efficiency, improvements of 2% projected, followed by coupling high-temperature solar concentrators to the splitting processes to reduce power requirements. Conceptual flowsheets developed from bench models are provided; materials investigations have concentrated on candidates which can withstand corrosive mixtures at temperatures up to 400 deg K, with Hastelloy C-276 exhibiting the best properties for containment and heat exchange to I2.

Besenbruch, G. E.; Chiger, H. D.; Mccorkle, K. H.; Norman, J. H.; Rode, J. S.; Schuster, J. R.; Trester, P. W.

1981-01-01

62

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

63

Development of Sulfuric Acid Decomposer for Thermo-Chemical IS Process  

SciTech Connect

The Japan Atomic Energy Agency (JAEA) has been conducting R and D on thermo-chemical Iodine-Sulfur (IS) process, which is one of most attractive water-splitting hydrogen production methods using nuclear heat of a high-temperature gas-cooled reactor (HTGR). In the IS process, sulfuric acid is evaporated and decomposed into H{sub 2}O and SO{sub 3} in a sulfuric acid decomposer operated under high temperature condition up to 500 deg C. Necessary heat is supplied by high temperature helium gas from the HTGR. Since the sulfuric acid decomposer will be exposed to severe corrosion condition, we have proposed a new decomposer concept of a block type heat exchanger made of SiC ceramic which has excellent corrosion and mechanical strength performance. To verify the concept, integrity of new type gaskets applied for boundary seal of the decomposer was examined as a first step. Pure gold gaskets coupled with absorption mechanism against thermal expansion showed good seal performance under 500 deg C. Based on this result, a mock-up model for a IS pilot-plant with 30 m{sup 3}/h-hydrogen production rate was test-fabricated as the next step. Through the fabrication and gas-tight tests, fabricability and structural integrity were confirmed. Also, the decomposer showed good mechanical strength and seal performances against horizontal loading simulating earthquake motion. (authors)

Hiroki, Noguchi; Hiroyuki, Ota; Atsuhiko, Terada; Shinji, Kubo; Kaoru, Onuki [IS Process Technology Group, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA) 4002 Narita, Oarai, Higashiibaraki, Ibaraki 311-1393 (Japan); Ryutaro, Hino [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), 4002 Narita, Oarai, Higashiibaraki, Ibaraki 311-1393 (Japan)

2006-07-01

64

In-process control of nitrogen and sulfur in entrained-bed gasifers. Final report  

Microsoft Academic Search

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 of concern are the nitrogen and sulfur oxides (NOx and SOx) which, without controls, are products of combustion of the gasifier product gas.

R. C. Adams; E. F. Aul; S. Kulkarni; R. A. McAllister; S. Margerum

1986-01-01

65

Current-voltage characteristic and sheet resistances after annealing of femtosecond laser processed sulfur emitters for silicon solar cells  

NASA Astrophysics Data System (ADS)

The characteristics of laser doped sulfur emitters are strongly dependent on annealing processes. We show how annealing increases the efficiency of silicon solar cells with such an emitter. Sheet resistance analysis reveals that up to an annealing temperature of 400 °C the emitter sheet resistivity increases. A lower sulfur donor concentration is concluded, which likely occurs by means of sulfur diffusion and capturing of sulfur donors at intrinsic silicon defects. Above that temperature, the emitter sheet resistance decreases, which we find to originate from healing of laser induced structural defects involving traps within the depletion zone of the silicon pn-junction.

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

2014-08-01

66

Process for removal of sulfur dioxide from gases  

Microsoft Academic Search

An improvement is provided in the regeneration system of agueous regenerative processes for the removal of SOâ from SOâ-containing gas streams which have a scrubbing system containing (1) a scrubbing zone through which a recirculating stream of sodium, potassium or ammonium thiosulfate solution continuously passes as a vehicle for the SOâ absorbent-sodium, potassium, or ammonium carbonate-under conditions favorable to the

Gorin

1980-01-01

67

Process for removal of sulfur dioxide from gases  

SciTech Connect

An improvement is provided in the regeneration system of agueous regenerative processes for the removal of SO/sub 2/ from SO/sub 2/-containing gas streams which have a scrubbing system containing (1) a scrubbing zone through which a recirculating stream of sodium, potassium or ammonium thiosulfate solution continuously passes as a vehicle for the SO/sub 2/ absorbent-sodium, potassium, or ammonium carbonate-under conditions favorable to the formation of sulfite by the reaction of carbonate and SO/sub 2/ and (2) a thiosulfate generation zone in which the sulfite is converted by sulfide to thiosulfate. The improvement comprises converting in a regenerating system, the net make of thiosulfate to sulfide and carbonate by converting one portion of the thiosulfate to formate and the reacting the other portion with said formate.

Gorin, E.

1980-09-02

68

Gasoline from natural gas by sulfur processing. Final technical report, June 1993--July 1996  

SciTech Connect

The overall objective of this research project was to develop a catalytic process to convert natural gas to liquid transportation fuels. The process, called the HSM (Hydrogen Sulfide-Methane) Process, consists of two steps that each use catalysts and sulfur-containing intermediates: (1) to convert natural gas to CS{sub 2} and (2) to convert CS{sub 2} to gasoline-range liquids. Experimental data generated in this project were for use in evaluating the commercial potential of the process.

Erekson, E.J.

1996-07-01

69

Molecular view of an electron transfer process essential for iron-sulfur protein biogenesis  

PubMed Central

Biogenesis of iron–sulfur cluster proteins is a highly regulated process that requires complex protein machineries. In the cytosolic iron–sulfur protein assembly machinery, two human key proteins—NADPH-dependent diflavin oxidoreductase 1 (Ndor1) and anamorsin—form a stable complex in vivo that was proposed to provide electrons for assembling cytosolic iron–sulfur cluster proteins. The Ndor1–anamorsin interaction was also suggested to be implicated in the regulation of cell survival/death mechanisms. In the present work we unravel the molecular basis of recognition between Ndor1 and anamorsin and of the electron transfer process. This is based on the structural characterization of the two partner proteins, the investigation of the electron transfer process, and the identification of those protein regions involved in complex formation and those involved in electron transfer. We found that an unstructured region of anamorsin is essential for the formation of a specific and stable protein complex with Ndor1, whereas the C-terminal region of anamorsin, containing the [2Fe-2S] redox center, transiently interacts through complementary charged residues with the FMN-binding site region of Ndor1 to perform electron transfer. Our results propose a molecular model of the electron transfer process that is crucial for understanding the functional role of this interaction in human cells. PMID:23596212

Banci, Lucia; Bertini, Ivano; Calderone, Vito; Ciofi-Baffoni, Simone; Giachetti, Andrea; Jaiswal, Deepa; Mikolajczyk, Maciej; Piccioli, Mario; Winkelmann, Julia

2013-01-01

70

Molecular view of an electron transfer process essential for iron-sulfur protein biogenesis.  

PubMed

Biogenesis of iron-sulfur cluster proteins is a highly regulated process that requires complex protein machineries. In the cytosolic iron-sulfur protein assembly machinery, two human key proteins--NADPH-dependent diflavin oxidoreductase 1 (Ndor1) and anamorsin--form a stable complex in vivo that was proposed to provide electrons for assembling cytosolic iron-sulfur cluster proteins. The Ndor1-anamorsin interaction was also suggested to be implicated in the regulation of cell survival/death mechanisms. In the present work we unravel the molecular basis of recognition between Ndor1 and anamorsin and of the electron transfer process. This is based on the structural characterization of the two partner proteins, the investigation of the electron transfer process, and the identification of those protein regions involved in complex formation and those involved in electron transfer. We found that an unstructured region of anamorsin is essential for the formation of a specific and stable protein complex with Ndor1, whereas the C-terminal region of anamorsin, containing the [2Fe-2S] redox center, transiently interacts through complementary charged residues with the FMN-binding site region of Ndor1 to perform electron transfer. Our results propose a molecular model of the electron transfer process that is crucial for understanding the functional role of this interaction in human cells. PMID:23596212

Banci, Lucia; Bertini, Ivano; Calderone, Vito; Ciofi-Baffoni, Simone; Giachetti, Andrea; Jaiswal, Deepa; Mikolajczyk, Maciej; Piccioli, Mario; Winkelmann, Julia

2013-04-30

71

Quantification and reduction of organic sulfur compound formation in a commercial wood pulping process.  

PubMed

This study experimentally quantified the formation of organic sulfur compounds in a commercial SuperBatch kraft pulping process using a laboratory pilot-scale digester. The results indicate that wood chips not only can adsorb HS- but also methyl mercaptan (MM) in the black liquor used for pretreatment during the two pretreatment stages. The absorption rate of MM is much faster than that of HS-. In the third stage of SuperBatch pulping, the rate of formation of MM and dimethyl sulfide (DMS) is very similar to that found in conventional batch kraft pulping processes. The study examined the applicability of the phase transition cooking (PTC) concept for reducing organic sulfur compounds in pulping, previously developed in laboratory batch pulping using a bomb-type digester, in a SuperBatch process. It was confirmed that there is a phase transition point (PTP) corresponding to PTC in SuperBatch pulping beyond which further delignification significantly increases the formation of volatile organic sulfur compounds. The results indicate that a 40% reduction of TRS formation can be achieved by using PTC. PMID:12038840

Zhu, J Y; Chai, X S; Pan, X J; Luo, Q; Li, J

2002-05-15

72

Processing of the Presequence of the Schizosaccharomyces pombe Rieske Iron-Sulfur Protein Occurs in a Single Step and Can Be  

E-print Network

Processing of the Presequence of the Schizosaccharomyces pombe Rieske Iron-Sulfur Protein Occurs¨r Biochemie I, D-60590 Frankfurt, Germany The iron-sulfur proteins of the cytochrome bc1 com- plexes sequence the S. pombe iron-sulfur protein is processed only once during import into mitochondria, whereas

Trumpower, Bernard L.

73

Experimental study on side-reaction occurrence condition in the iodine–sulfur thermochemical hydrogen production process  

Microsoft Academic Search

In iodine–sulfur thermochemical hydrogen production process (IS process), side-reactions from HI, H2SO4 and I2 mixture solution were investigated experimentally in operating temperature ranges, from 295 to 368 K. The effects of the reaction temperature, acid concentration, iodine concentration and the ratio of the amount of H2SO4 to that of HI on the sulfur formation are discussed. The quantitative reaction analysis was

Makoto Sakurai; Hayato Nakajima; Rusli Amir; Kaoru Onuki; Saburo Shimizu

2000-01-01

74

Simultaneous bioreduction of nitrate and chromate using sulfur-based mixotrophic denitrification process.  

PubMed

This study aims at evaluating simultaneous chromate and nitrate reduction using sulfur-based mixotrophic denitrification process in a column reactor packed with elemental sulfur and activated carbon. The reactor was supplemented with methanol at C/N ratio of 1.33 or 2. Almost complete denitrification was achieved at influent NO3(-)-N and Cr(VI) concentrations of 75 mg/L and 10mg/L, respectively, and 3.7h HRT. Maximum denitrification rate was 0.5 g NO3(-)-N/(L.d) when the bioreactor was fed with 75 mg/L NO3(-)-N, 150 mg/L methanol and 10mg/L Cr(VI). The share of autotrophic denitrification was between 12% and 50% depending on HRT, C/N ratio and Cr(VI) concentration. Effluent total chromium was below 50 ?g/L provided that influent Cr(VI) concentration was equal or below 5mg/L. DGGE results showed stable microbial community throughout the operation and the presence of sulfur oxidizing denitrifying bacteria (Thiobacillus denitrificans) and Cr(VI) reducing bacteria (Exiguobacterium spp.) in the column bed. PMID:24035799

Sahinkaya, Erkan; Kilic, Adem; Calimlioglu, Beste; Toker, Yasemin

2013-11-15

75

Process for the hydroformylation of sulfur-containing thermally cracked petroleum residue and novel products thereof  

SciTech Connect

This patent describes a hydroformylation-hydrogenation process comprising reacting an olefinic cracked petroleum distillate feed, produced from petroleum residue by high temperature thermal cracking, and containing C{sub 5} to C{sub 35}-1-n-alkyl olefins as the major type of olefin components, and organic sulfur compounds in concentrations exceeding 0.1% sulfur. It comprises at first with carbon monoxide and hydrogen at temperatures between about 50 and 250{degrees} C and pressures in the range of 50 to 6000 psi; in the presence of a Group VIII transition metal carbonyl complex catalyst in effective amounts to produce aldehydes of a semilinear character having an average of less than one alkyl branch per molecule and 20% by weight or more linear isomers, then with molecular hydrogen at temperatures between 100 and 250{degrees} C and pressures between 200 psi and 5000 psi (13.6 and 340 atm) in the presence of a hydrogenation catalyst in effective amounts the catalyst being sulfur resistant cobalt, molybdenum, nickel, or tungsten or a sulfide thereof to produce the corresponding alcohols of a semilinear character having an average of less than one alkyl branch per molecule and 20% by weight or more linear isomers, then with molecular hydrogen at temperatures between 100 and 250{degrees} C and pressures between 200 psi and 5000 psi (13.6 and 340 atm) in the presence of a hydrogenation catalyst in effective amounts the catalyst being sulfur resistant cobalt, molybdenum, nickel, or tungsten or a sulfide thereof to produce the corresponding alcohols of a semilinear character having an average of less than one alkyl branch per molecule.

Oswald, A.A.; Bhatia, R.N.; Mozeleski, E.J.; Glivicky, A.P.; Brueggeman, B.G.; Hooten, J.R.; Smith, C.M.; Hsu, C.S.

1991-07-09

76

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

77

Two-step Processing Is Not Essential for the Import and Assembly of Functionally Active Iron-Sulfur Protein into the Cytochrome bc1  

E-print Network

Two-step Processing Is Not Essential for the Import and Assembly of Functionally Active Iron-Sulfur From the Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755 The iron-sulfur for import and assembly of the iron-sulfur protein into the cytochrome bc1 complex, we mutagenized the prese

Trumpower, Bernard L.

78

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

79

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

80

Coupled sulfur isotopic and chemical mass transfer modeling: Approach and application to dynamic hydrothermal processes  

SciTech Connect

A computational modeling code (EQPSreverse arrowS) has been developed to examine sulfur isotopic distribution pathways coupled with calculations of chemical mass transfer pathways. A post processor approach to EQ6 calculations was chosen so that a variety of isotopic pathways could be examined for each reaction pathway. Two types of major bounding conditions were implemented: (1) equilibrium isotopic exchange between sulfate and sulfide species or exchange only accompanying chemical reduction and oxidation events, and (2) existence or lack of isotopic exchange between solution species and precipitated minerals, parallel to the open and closed chemical system formulations of chemical mass transfer modeling codes. All of the chemical data necessary to explicitly calculate isotopic distribution pathways is generated by most mass transfer modeling codes and can be input to the EQPS code. Routines are built in to directly handle EQ6 tabular files. Chemical reaction models of seafloor hydrothermal vent processes and accompanying sulfur isotopic distribution pathways illustrate the capabilities of coupling EQPSreverse arrowS with EQ6 calculations, including the extent of differences that can exist due to the isotopic bounding condition assumptions described above. 11 refs., 2 figs.

Janecky, D.R.

1988-09-21

81

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

82

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

83

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

84

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

85

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

86

Gasoline from natural gas by sulfur processing. Quarterly report No. 11, January--March 1996  

SciTech Connect

The overall objective of this research project is to develop a catalytic process to convert natural gas to liquid transportation fuels. The process consists of two steps that each use catalysts and sulfur-containing intermediates: (1) converting natural has to CS{sub 2} and (2) converting CS{sub 2} to gasoline-range liquids. Experimental data will be generated to demonstrate the potential of catalysts and the overall process. During this quarter, progress in the following areas has been made: Hydrogenation of CS{sub 2} to liquid hydrocarbons was accomplished on two sets of catalyst a cobalt exchanged ZSM-5 and a mixture containing MoS{sub 2} hydrogenation catalyst and HZSM-5. CS{sub 2} conversions of up to 100% were achieved. The highest selectivity to C{sub 4}{sup +} hydrocarbons was 52%. There is interest within the oil companies we contacted for a process that converts natural gas to liquid hydrocarbons. In addition there is also interest in a process that produces hydrogen for a refinery, while at the same time it removes hydrogen sulfide.

Erekson, E.J.

1996-05-01

87

The Influence of Sulfur Promoter on the Production of SWCNTs by the Arc-Discharge Process  

NASA Astrophysics Data System (ADS)

The influence of sulfur addition on the production of SWCNTs by the arc-discharge method with Fe/Y catalysts was investigated. It was found that the yield of SWCNTs is strongly influenced by the presence of sulfur. The dependence of the SWCNTs yield on the concentration of sulfur in the anode reaches its maximum around 1.5 at%. The yield of SWCNTs was estimated by thermal gravimetry and by optical absorption.

Haluška, M.; Skákalová, V.; Carroll, D.; Roth, S.

2005-09-01

88

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

89

Sulfur barrier for use with in situ processes for treating formations  

SciTech Connect

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

90

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

91

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 ...

92

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...

93

USING THE SULFUR POLYMER STABILIZATION SOLIDIFICATION PROCESS TO TREAT RESIDUAL MERCURY WASTES FROM GOLD MINING OPERATIONS.  

SciTech Connect

Large quantities of mercury are generated as a by-product during the processing of gold ore following mining operations. Newmont Mining Corporation (NMC), which operates some of the world's largest gold mines, sought a method to permanently ''retire'' its mercury by-products, thereby avoiding potential environmental liability. Sulfur Polymer Stabilization-Solidification (SPSS) is an innovative technology developed at Brookhaven National Laboratory (BNL) for treatment of mercury and mercury contaminated materials, such as soil, sludge and debris. BNL conducted a treatability study to determine the potential applicability of SPSS for treatment of Newmont mercury, and the treated product passed the U.S. Environmental Protection Agency (EPA) test for toxicity. The SPSS process has been shown to be effective on radioactive and nonradioactive mercury and mercury-contaminated materials with a pilot-scale batch system capable of producing 0.03 m{sup 3} (1 ft{sup 3}) per batch. Engineering scale-up issues are discussed and material property tests addressing these issues are described.

BOWERMAN,B.ADAMS,J.KALB,P.WAN,R.Y.LEVIER,M.

2003-02-24

94

[Microbiological processes of the carbon and sulfur cycle in cold methane seeps in the North Atlantic].  

PubMed

Functioning of microbial communities in surface sediments of the Haakon Mosby underwater mud volcano (lat. 72 degrees N) and in gas seepage fields of the Vestnesa Ridge was investigated using Mir-1 and Mir-2 deep-sea submersibles during the 40th expedition of the research vessel Academician Mstislav Keldysh. Large areas of sedimentary deposits of the Haakon Mosby mud volcano (HMMV) and pockmarks of the Vestnesa Ridge (VR) are covered with bacterial mats 0.1 to 0.5 cm thick. The microbial community making up bacterial mats of the HMMV was predominated by large filamentous bacteria with filaments measuring up to 100 microns in length and 2 to 8 microns in width. The occurrence of rosettes allowed the observed filamentous bacteria to be referred to the morphologically similar genera Leucothrix or Thiothrix. Three morphological types of filamentous bacteria were identified in bacterial mats covering VR pockmarks. Filaments of type one are morphologically similar with representatives of the genera Thioploca or Desmanthos. Type two filaments had numerous inclusions of sulfur and resembled representatives of the genus Thiothrix. The third morphological type was constituted by single filaments made up of tightly connected disk-like cells and can, apparently, be assigned to the genus Beggiatoa. The rates of methane oxidation (up to 1570 microliters C/(dm3 day)) and sulfate reduction (up to 17 mg S/(dm3 day)) measured in surface sediments of HMMV and VR were close to the maximum rates of these processes observed in badly polluted regions of the northwestern shelf of the Black Sea. High rates of microbiological processes correlated with the high number of bacteria. The rate of methane production in sediments studied was notably lower and ranged from 0.1 to 3.5 microliters CH4/(dm3 day). Large areas of the HMMV caldera were populated by pogonophoras, represented by the two species, Sclerolinum sp. and Oligobrachia sp. The mass development of Sclerolinum sp. in the HMMV caldera was by the activity of aerobic methane-oxidizing bacteria localized inside the cells of these animals. Bacterial cells were also found in the trophosome tissue of Oligobrachia sp., but in cells of these bacteria, we did not observe the membrane structures typical of methanotrophs. The localization pattern of pogonophoras on the surface of reduced sediments suggests that the predominant bacteria in Oligobrachia tissues are sulfur-oxidizing endosymbionts. PMID:11195584

Pimenov, N V; Savvichev, A S; Rusanov, I I; Lein, A Iu; Ivanov, M V

2000-01-01

95

Linking Food Webs and Biogeochemical Processes in Wetlands: Insights From Sulfur Isotopes  

NASA Astrophysics Data System (ADS)

To better understand the transfer of nutrients into prairie wetland food webs we have investigated the cycling of S (via S isotope systematics and geochemistry) in a prairie wetland landscape by characterizing sources (ground water, interstitial water, surface water) and processes in a small catchment comprised of four wetlands in eastern South Dakota. We focused on S to derive process information that is not generally available from carbon isotopes alone. The wetlands chosen for study spanned a considerable range in SO4 concentration (0.1-13.6 mM), which corresponded with landscape position. Ground water ?34SSO4 values remained relatively constant (mean = -13.2 per mil) through time. However, ?34SSO4 values of wetland surface waters ranged from -2.9 to -30.0 per mil (CDT) and were negatively correlated with SO4 concentrations (p<0.05). The isotopic variability of surface water SO4 resulted from mixing with re-oxidized sulfides associated with recently flushed wetland soils. The ?34S signatures of wetland primary (Gastropoda: Stagnicola elodes) and secondary (Odonata: Anax sp.) consumers were significantly related to surface water ?34SSO4 values (p<0.05) suggesting that food web components were responding to changes in the isotopic composition of the S source. Both primary and secondary consumer ?34S signatures differed between wetlands (ANOVA, p<0.05). These data illustrate the complexity of S cycling in prairie wetlands and the influence of wetland hydrologic and biogeochemical processes on prairie wetland food webs. Additionally, this work has demonstrated that sulfur isotopes can provide unique source and process information that cannot be derived from traditional carbon and nitrogen isotope studies.

Stricker, C. A.; Guntenspergen, G. R.; Rye, R. O.

2005-05-01

96

Bench-scale testing and evaluation of the direct sulfur recovery process. Final report, February 1990--March 1994  

SciTech Connect

The Direct Sulfur Recovery Process (DSRP) is a two-stage catalytic reduction process for efficiently recovering up to 99% or higher amounts of elemental sulfur from SO{sub 2}-containing regeneration tail-gas produced in advanced integrated gasification combined cycle (IGCC) power systems by reacting the tail-gas with a small slipstream of coal gas. In this project, the DSRP was demonstrated with simulated gases at bench-scale with 3-in. diameter, 1-L size catalytic reactors. Fundamental kinetic and modeling studies were conducted to explain the significantly higher than thermodynamically expected sulfur recoveries in DSRP and to enable prediction of sulfur recovery in larger reactors. Technology transfer activities to promote the DSRP consisted of publications and discussions with architectural engineering firms and industrial parties especially IGCC system developers. Toward the end of the project, an agreement was signed with an IGCC system developer to scale up the DSRP and test it with actual gases in their 10-MW (thermal) coal gasification pilot-plant under a cooperative R&D agreement with the US Department of Energy.

Gangwal, S.K.; Chen, D.H.

1994-05-01

97

Study of a regenerative process for selective sulfur dioxide removal using organic solvents  

SciTech Connect

In searching appropriate solvents for selective sulfur dioxide removal it has been found that sulfur dioxide solubility can be well correlated by the Gutmann donor number of the solvent. Two solvents, N-methylpyrrolidone (NMP) and methyldiethanolamine (MDEA), have been selected for experiments. Mixtures of sulfur dioxide and solvent (1:1 mole ratio) have been prepared at low temperature. These mixtures give complexes, stable under the experimental conditions, with a melting point well above the melting point of the separate components. These mixtures have been analyzed by infra red, ultraviolet/visible and nuclear magnetic resonance spectroscopy. Solubility of sulfur dioxide in NMP and MDEA has been measured at 25{degrees}C in the range of 2000-5000 ppmv using a stirred tank reactor. 14 refs., 4 figs., 2 tabs.

Van Dam, M.H.H.; Lamine, A.S. [Laboratorie des Sciences du Genie Chimiques (France)] [and others

1996-12-31

98

Sulfur isotopes as indicators of amended bacterial sulfate reduction processes influencing field scale uranium bioremediation.  

PubMed

Aqueous uranium (U(VI)) concentrations in a contaminated aquifer in Rifle Colorado have been successfully lowered through electron donor amended bioreduction. Samples collected during the acetate amendment experiment were analyzed for aqueous concentrations of Fe(ll), sulfate, sulfide, acetate, U(VI), and delta(34)S of sulfate and sulfide to explore the utility of sulfur isotopes as indicators of in situ acetate amended sulfate and uranium bioreduction processes. Enrichment of up to 7% per hundred in delta(34)S of sulfate in down-gradient monitoring wells indicates a transition to elevated bacterial sulfate reduction. A depletion in Fe(II), sulfate, and sulfide concentrations atthe height of sulfate reduction, along with an increase in the delta(34)S of sulfide to levels approaching the delta(34)S values of sulfate, indicates sulfate limited conditions concurrent with a rebound in U(VI) concentrations. Upon cessation of acetate amendment, sulfate and sulfide concentrations increased, while delta(34)S values of sulfide returned to less than -20% per hundred and sulfate delta(34)S decreased to near-background values, indicating lower levels of sulfate reduction accompanied by a corresponding drop in U(VI). Results indicate a transition between electron donor and sulfate-limited conditions at the height of sulfate reduction and suggest stability of biogenic FeS precipitates following the end of acetate amendment. PMID:19031870

Druhan, Jennifer L; Conrad, Mark E; Williams, Kenneth H; N'Guessan, Lucie; Long, Philip E; Hubbard, Susan S

2008-11-01

99

Sulfur Earth  

NASA Astrophysics Data System (ADS)

Variations in surface tension affect the buoyancy of objects floating in a liquid. Thus an object floating in water will sink deeper in the presence of dishwater fluid. This is a very minor but measurable effect. It causes for instance ducks to drown in aqueous solutions with added surfactant. The surface tension of liquid iron is very strongly affected by the presence of sulfur which acts as a surfactant in this system varying between 1.9 and 0.4 N/m at 10 mass percent Sulfur (Lee & Morita (2002), This last value is inferred to be the maximum value for Sulfur inferred to be present in the liquid outer core. Venting of Sulfur from the liquid core manifests itself on the Earth surface by the 105 to 106 ton of sulfur vented into the atmosphere annually (Wedepohl, 1984). Inspection of surface Sulfur emission indicates that venting is non-homogeneously distributed over the Earth's surface. The implication of such large variation in surface tension in the liquid outer core are that at locally low Sulfur concentration, the liquid outer core does not wet the predominantly MgSiO3 matrix with which it is in contact. However at a local high in Sulfur, the liquid outer core wets this matrix which in the fluid state has a surface tension of 0.4 N/m (Bansal & Doremus, 1986), couples with it, and causes it to sink. This differential and diapiric movement is transmitted through the essentially brittle mantle (1024 Pa.s, Lambeck & Johnson, 1998; the maximum value for ice being about 1030 Pa.s at 0 K, in all likely hood representing an upper bound of viscosity for all materials) and manifests itself on the surface by the roughly 20 km differentiation, about 0.1 % of the total mantle thickness, between topographical heights and lows with concomitant lateral movement in the crust and upper mantle resulting in thin skin tectonics. The brittle nature of the medium though which this movement is transmitted suggests that the extremes in topography of the D" layer are similar in range to those observed on the Earth's surface and are mimicked by lows under the oceans and highs under the altiplanos. Careful and area selective S wave core mantle ellipsometry might be able to discern these core-mantle topographic variations. As such this process demonstrates the validity of the Gaia hypothesis enunciated by Baas Becking(1931) that no ecological niche on our planet is closed off from other niches "nothing in the world is single".

de Jong, B. H.

2007-12-01

100

Process for the regeneration of an additive used to control emissions during the combustion of high sulfur fuel  

SciTech Connect

A process is described for regenerating a sulfur capturing additive used in the preparation of a hydrocarbon in water emulsion for combustion as a fuel comprising: (a) forming a hydrocarbon in water emulsion by admixing a sulfur containing hydrocarbon and water with an emulsifier and a water soluble sulfur capturing additive wherein the sulfur capturing additive is selected from the group consisting of Na/sup +/, K/sup +/, Li/sup +/, Ca/sup ++/, Ba/sup ++/, Mg/sup ++/, Fe/sup +++/ and mixtures thereof; (b) burning the emulsion so as to form a combustion ash containing the water soluble additive as a sulfate compound; (c) leaching the combustion ash wherein the combustion ash is leached with water in a water to ash ratio in ml to grams of 1:1 to 30:1 so as to dissolve the water soluble additive sulfate compound to form a pregnant leach liquor containing the additive; (d) separating the pregnant leach liquor containing the additive; (e) adjusting the pregnant leach liquor with a basic precipitating agent wherein the base precipitating agent is selected from the group consisting of NH/sub 4/OH, NaOH, Ca(OH)/sub 2/, NaCO/sub 3/ and mixtures thereof wherein the pregnant leach liquor is adjusted with the base to a pH of greater than 7 so as to precipitate an additive compound; and (f) recovering the additive compound.

Polanco, D.R.; Bueno, C.O.; Salazar, R.; Chamorra, F.A.S

1989-05-23

101

[Microbial processes of the carbon and sulfur cycles in the White Sea].  

PubMed

The present paper contains the results of our microbiological and biogeochemical investigations carried out during a series of expeditions to the White Sea in 2002-2006. The studies were conducted in the open part of the White Sea, as well as in the Onega, Dvina, and Kandalaksha bays. In August 2006, the photosynthetic productivity in the surface water layer was low (47-145 mg C m(-2) day(-1)). Quantitative characteristics of microbial numbers and activity of the the key microbial processes occurring in the water column of the White Sea were explored. Over the 5-year period of observations, the total number of bacterial cells in the surface layer of the water column varied from 50 to 600 thousand cells ml(-1). In August 2006, bacterioplankton production (BP) was estimated to be 0.26-3.3 microg C l(-1) day(-1); the P/B coefficient varied from 0.22 to 0.93. The suspended organic matter had a lighter isotope composition (from -28.0 to -30.5 per thousand) due to the predominance of terrigenous organic matter delivered by the Northern Dvina waters. The interseasonal and interannual variation coefficients for phytoplankton production and BP numbers are compared. The bacterioplankton community of the White Sea's deep water was found to be more stable than that of the surface layer. In the surface layer of bottom sediments, methane concentration was 0.2-5.2 microl dm(-3); the rate of bacterial sulfate reduction was 18-260 microg S dm(-3) day(-1); and the rates of methane production and oxidation were 24-123 and 6-13 nl CH4 dm(-3) day(-1) respectively. We demonstrated that the rates of microbial processes of the carbon and sulfur cycles occurring in the sediments of the White Sea basin were low. PMID:19137722

Savvichev, A S; Rusanov, I I; Zakharova, E E; Veslopolova, E F; Mitskevich, I N; Kravchishina, M D; Lein, A Iu; Ivanov, M V

2008-01-01

102

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

103

A demonstration study on a closed-cycle hydrogen production by the thermochemical water-splitting iodine–sulfur process  

Microsoft Academic Search

Japan Atomic Energy Research Institute (JAERI) has been conducting R&D on thermochemical hydrogen production using the water-splitting iodine–sulfur process, as part of the research programs striving to utilize heat from a high temperature gas-cooled reactor (HTGR). The R&D is currently at the bench-scale stage and covers several fields including the evaluation of structural materials in corrosion environments, the improvement in

Shinji Kubo; Hayato Nakajima; Seiji Kasahara; Syunichi Higashi; Tomoo Masaki; Hiroyoshi Abe; Kaoru Onuki

2004-01-01

104

Decoupling of sulfur and nitrogen cycling due to biotic processes in a tropical rainforest  

NASA Astrophysics Data System (ADS)

We examined the terrestrial sulfur (S) cycle in the wet tropical Luquillo Experimental Forest (LEF), Puerto Rico. In two previously instrumented watersheds (Icacos and Bisley), chemical and isotopic measurements of carbon (C), nitrogen (N) and S were used to explore the inputs, in-soil processing, and losses of S through comparison to the N cycle. Additionally, the impact of soil forming factors (particularly climate, organisms, topography and parent material) on S cycling in this system was considered. Atmospheric inputs (?34S values of 16.1 ± 2.8‰), from a mixture of marine and anthropogenic sources, delivered an estimated 2.2 g S/(m2yr) at Icacos, and 1.8 g S/(m2yr) at Bisley. Bedrock N and S inputs to soil were minimal. We estimated a hydrologic export of 1.7 ± 0.1 g S/(m2yr) at Icacos, and 2.5 ± 0.2 g S/(m2yr) at Bisley. Stream baseflow S isotope data revealed significant bedrock S in the hydrologic export at Bisley (with a distinctive ?34S values of 1.6 ± 0.7‰), but not at Icacos. Pore water data supported the co-occurrence of at least three major biological S-fractionating processes in these soils: plant uptake, oxidative degradation of organic S and bacterial sulfate reduction. The rates and relative importance of these processes varied in time and space. Vegetation litter was 3-5‰ depleted in 34S compared to the average pore water, providing evidence for fractionation during uptake and assimilation. Out of all abiotic soil forming factors, climate, especially the high rainfall, was the main driver of S biogeochemistry in the LEF by dictating the types and rates of processes. Topography appeared to impact S cycling by influencing redox conditions: C, N and S content decrease downslope at all sites, and the Bisley lower slope showed strongest evidence of bacterial sulfate reduction. Parent material type did not impact the soil S cycle significantly. To compare the fate of S and N in the soil, we used an advection model to describe the isotopic fractionation of total S and N associated with downward movement of organic matter in both dissolved and solid fractions. This model worked well for N, but the assumption of a constant fractionation factor ? with depth failed to describe S transformations. This result revealed a fundamental difference between N and S cycling in these soils, indicating an apparent greater sensitivity of S isotopes to fluctuating redox conditions.

Yi-Balan, Simona A.; Amundson, Ronald; Buss, Heather L.

2014-10-01

105

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

106

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

107

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

108

Controlled comparison of advanced froth flotation process technology and economic evaluations for maximizing BTU recovery and pyritic sulfur rejection  

SciTech Connect

The overall objective of this round robin project was to select the most efficient, as determined by the efficiency index, cost effective, as determined by the annual cost per ton of SO{sub 2} removed, advanced flotation device available. This machine was to process ultra fine coal, maximize Btu recovery and maximize pyritic sulfur rejection. The device will first be installed as a one hundred pound per hour capacity unit and, subject to the outcome of Task 6 of the Engineering Development Contract, increased to a 3 ton per hour capacity unit for installation into a proof-of-concept preparation plant. All of the technical and economic results were submitted to the TST for consideration. The TST members evaluated the data and determined to rank each of the participants 50% on technical merit and 50% on economic merit. The technical merit was to be the efficiency index. The economical merit was to be the annual dollars per ton of clean coal corrected for carrying capacity and frother concentration and the results of Test No. 4. This factor does not penalize a particular technology for not meeting a 90% pyritic sulfur rejection and therefore leaves something to be desired as the only economic basis for decision. A second economic evaluation criteria was required that considered the $/ton of sulfur dioxide removed. The technical and economic factors were calculated and added together for the final evaluation ranking. The technical factor was calculated by multiplying the efficiency index for each participant by 0.5. The two economic factors were calculated by dividing 1000 by the $/ton of clean coal and multiplying by 0.5 and by dividing 10,000 by the $/ton of sulfur dioxide removed and multiply by 0.5. The 1000 and 10,000 are numbers selected such that when divided by their economic factors, respective numbers resulted in a two digit number. The results of these calculations are discussed. 4 refs., 18 figs., 27 tabs.

Harrison, K.E.; Ferris, D.D. (ICF Kaiser Engineers, Inc., Pittsburgh, PA (USA)); Kosky, R.M. (Consolidation Coal Co., Pittsburgh, PA (USA)); Warchol, J.J.; Musiol, W.F.; Shiao, S.Y. (Babcock and Wilcox Co., New Orleans, LA (USA)); Luttrell, G.H.; Adel, G.T.; Yoon, R.H. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA))

1990-01-01

109

Bioenergetic and metabolic processes for the survival of sulfur-deprived Dunaliella salina (Chlorophyta)  

Microsoft Academic Search

The work addressed bioenergetic, metabolic and physiological responses ofthe green alga Dunaliella salina to sulfur (S)-deprivation. Photo-autotrophically grown cells were suspended in a medium in which thesulfates were replaced by chloride salts. Growth characteristics, pigmentcontent, rates of photosynthesis and respiration, as well as endogenoussubstrate (starch and protein) accumulation were monitored as a functionof time under S-deprivation. Lack of S from

Huimin Cao; Liping Zhang; Anastasios Melis

2001-01-01

110

Phosphonobetaine\\/sulfur dioxide copolymer by Butler’s cyclopolymerization process  

Microsoft Academic Search

The zwitterionic monomer, ethyl 3-(N,N-diallylammonio)propanephosphonate and sulfur dioxide were cyclocopolymerized in DMSO using azobisisobutyronitrile or ammonium persulfate as initiators to afford a pH-responsive polyphosphonobetaine\\/SO2 (PPB\\/SO2) copolymer. The polymers, on treatment with HCl and NaOH, gave the aqueous solutions of the corresponding cationic polyphosphononic acid (CPP) and anionic polyphosphonate (APP). The solution properties of the PPB having two pH-responsive functionalities were

N. Y. Abu-Thabit; Izzat W. Kazi; Hasan A. Al-Muallem; Shaikh A. Ali

2011-01-01

111

Development of instrumental methods of analysis of sulfur compounds in coal process streams. Quarterly technical progress report for October-December 1980  

SciTech Connect

Work is in progress on the preparation of a user-oriented computer software manual, for estimating sulfur speciation in aqueous coal process streams form a thermodynamic data base. Capabilities and limitations of sulfide and polysulfide analysis by differential pulse polarography at a dropping mercury anode are assessed critically. Thallous nitrate used as the titrant reagent in a thermometric enthalpy titration yields the molar sum of monosulfide and polysulfide. Inorganic sulfur has been successfully speciated in coal conversion by-product water samples. A combination of differential pulse voltammetry, thermometric enthalpy titrations and classical methods was used. One hundred percent of the total sulfur present was quantitatively accounted for.

Jordan, J.; Stutts, J. D.; Ankabrandt, S. J.; Stahl, J.; Yakupkovic, J. E.

1981-01-01

112

The global sulfur cycle  

NASA Technical Reports Server (NTRS)

The results of the planetary biology microbial ecology's 1984 Summer Research Program, which examined various aspects of the global sulfur cycle are summarized. Ways in which sulfur flows through the many living and chemical species that inhabit the surface of the Earth were investigated. Major topics studied include: (1) sulfur cycling and metabolism of phototropic and filamentous sulfur bacteria; (2) sulfur reduction in sediments of marine and evaporite environments; (3) recent cyanobacterial mats; (4) microanalysis of community metabolism in proximity to the photic zone in potential stromatolites; and (5) formation and activity of microbial biofilms on metal sulfides and other mineral surfaces. Relationships between the global sulfur cycle and the understanding of the early evolution of the Earth and biosphere and current processes that affect global habitability are stressed.

Sagan, D. (editor)

1985-01-01

113

Recent development of a simultaneous sulfur and dust removal process for IGCC power generation system  

SciTech Connect

A 4t/d Moving Bed Hot Gas Cleanup System was jointly tested by the Engineering Association for Integrated Coal Gasification Combined Cycle Power System and Kawasaki Heavy Industries, Ltd. (KHI), branching coal gas from 200 t/d IGCC pilot plant at Nakoso, Fukushima Prefecture, Japan. The operation started February, 1992 and completed December 1995 with 1,702 hrs of cumulative time of gas introduction. Tests were executed successfully: sulfur and dust concentration in the outlet stream under standard operation condition were under 40 ppmv and under several mg/m{sub N}{sup 3} respectively, that are well below the target values.

Kamei, Kenji; Kawamata, Naoyuki [Kawasaki Heavy Industries, Ltd., Tokyo (Japan). Technology Development Headquarters; Ishikawa, Katsuya; Shindo, Kenjiro; Syoji, Takatoshi [Akashi Technical Inst. (Japan); Maeda, Yoshiji; Izumi, Noriaki; Funahashi, Kimihiro; Yanai, Makoto [Industrial Plant Engineering Div., Kobe (Japan)

1996-12-31

114

MHUG process for production of low sulfur and low aromatic diesel fuel. [Medium-pressure Hydro UpGrading  

SciTech Connect

A new hydro-upgrading process operated under medium pressure has been developed to reduce the sulfur and the aromatics content in light cycle oil (LCO). Two catalysts were used in series in this technology. The commercial RN-1 catalyst, which is known as having high activity in hydrodenitrogenation, desulfurization and aromatic saturation, was chosen as the first catalyst. The second one was a nickel-tungsten zeolite catalyst, named RT-5, which was developed by RIPP specially for hydrogenolysis of naphthenic and aromatic hydrocarbons. The pilot plant tests showed that high quality diesel oil with aromatics content less than 20 v% and sulfur content less than 0.05 wt% could be produced from various LCO/straight-run-gas-oil (SRGO) blended feedstocks under hydrogen partial pressure of 6.4 MPa. The reaction temperature and overall space velocity (S.V.) varied in the range of 350--380 C and 0.6--1.2 h[sup [minus]1], respectively, depending on the properties of the feedstocks to be processed and the upgrading depth required. Several examples presented also illustrated that this technology could be used to prepare catalytic reforming feedstock as well, which is in urgent need in China. A life test operated in relatively high severity for 3,000 hr. indicated that the catalysts possessed excellent stability. A commercial demonstration unit has been running well since the last Oct 1.

Shi, Yu Lin; Shi, Jian Wen; Zhang, Xin Wei; Shi, Ya Hua; Li, Da Dong (SINOPEC, Beijing (China). Research Inst. of Petroleum Processing)

1993-01-01

115

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

116

Sulfur Mustard  

MedlinePLUS

... than air, so it will settle in low-lying areas. Immediate signs and symptoms of sulfur mustard ... heavier than air and will settle in low-lying areas. If avoiding sulfur mustard exposure is not ...

117

Zeolites Remove Sulfur From Fuels  

NASA Technical Reports Server (NTRS)

Zeolites remove substantial amounts of sulfur compounds from diesel fuel under relatively mild conditions - atmospheric pressure below 300 degrees C. Extracts up to 60 percent of sulfur content of high-sulfur fuel. Applicable to petroleum refineries, natural-gas processors, electric powerplants, and chemical-processing plants. Method simpler and uses considerably lower pressure than current industrial method, hydro-desulfurization. Yields cleaner emissions from combustion of petroleum fuels, and protects catalysts from poisoning by sulfur.

Voecks, Gerald E.; Sharma, Pramod K.

1991-01-01

118

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

119

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

120

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

121

Process for producing benzene by hydrodealkylation of a hydrocarbon fraction comprising alkylaromatic hydrocarbons, olefinic hydrocarbons and sulfur compound  

SciTech Connect

A stabilized hydrocarbon fraction comprising toluene, xylene, sulfur and olefinic hydrocarbons is converted to benzene by catalytic hydrodesulfurization, hydrodealkylation and catalytic hydrogenation.

Derrien, M.; Cosyns, J.

1984-07-31

122

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

123

Sulfur cycle  

Microsoft Academic Search

Even granting our uncertainties about parts of our model of the sulfur cycle, we can draw some conclusions from it. Man is now contributing about one half as much as nature to the total atmospheric burden of sulfur compounds, but by A.D. 2000 he will be contributing about as much, and in the northern hemisphere alone he will be more

W. W. Kellogg; R. D. Cadle; E. R. Allen; A. L. Lazrus; E. A. Martell

1972-01-01

124

Linking Food Webs and Biogeochemical Processes in Wetlands: Insights From Sulfur Isotopes  

Microsoft Academic Search

To better understand the transfer of nutrients into prairie wetland food webs we have investigated the cycling of S (via S isotope systematics and geochemistry) in a prairie wetland landscape by characterizing sources (ground water, interstitial water, surface water) and processes in a small catchment comprised of four wetlands in eastern South Dakota. We focused on S to derive process

C. A. Stricker; G. R. Guntenspergen; R. O. Rye

2005-01-01

125

Novel characterization of Radix Angelicae Dahuricae before and after the sulfur-fumigation process by combining high performance liquid chromatographic fingerprint and multi-ingredients determination  

PubMed Central

Background: Harmful sulfur-fumigation processing method is abused during Radix Angelicae Dahuricae preparation. However, the analytical technique characterizing Radix Angelicae Dahuricae before and after the sulfur-fumigation process is absent. Materials and Methods: The high performance liquid chromatography (HPLC) technique was adopted to develop methods combining finger-print analysis and multi-ingredients simultaneous determination for quality evaluation of Radix Angelicae Dahuricae before and after the sulfur-fumigation process. The chromatographic fingerprint method was established for qualitative analysis coupled with statistical cluster analysis basing on Euclidean distance. Additionally, a determination method was developed for quantitative analysis, which was able to assay the concentrations of the major coumarins including imperatorin, isoimperatorin, xanthotoxin, xanthotoxol, isoimpinellin, oxypeucedanin, and bergapten in Radix Angelicae Dahuricae simultaneously. The separations of the two methods were both achieved on a Hypersil octadecylsilyl C18 column (250 mm × 4.6 mm, 5 ?m) at 35°C under different strategic gradient elution programs. The detection wavelength was set at 254 nm all the time. Method validation data indicated that the methods were both reliable and applicable. They were then used to assay different Radix Angelicae Dahuricae samples collected from good agricultural practice (GAP) bases and local herbal markets. Results: The successful application demonstrated that the combination of HPLC fingerprint and simultaneous quantification of multi-ingredients offers an efficient approach for quality evaluation of Radix Angelicae Dahuricae before and after the sulfur-fumigation process. Conclusion: In order to discriminate Radix Angelicae Dahuricae before and after the sulfur-fumigation process, oxypeucedanin, and xanthotoxol were the most sensitive biomarkers and should be determined. PMID:25210323

Liu, Xiao; Liu, Jingjing; Cai, Hao; Li, Songlin; Ma, Xiaoqing; Lou, Yajing; Qin, Kunming; Guan, Hongyue; Cai, Baochang

2014-01-01

126

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

127

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

128

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

129

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

130

Recovery of vanadium in deep processing of medium- and high-sulfur crude oils and bitumens  

Microsoft Academic Search

Recovery of vanadium from the products of crude oil and hit=men processing has become an active issue because of the shortage of vanadium, the rarity of vanadium ore deposits, and the low concentrations of vanadium in the richest ores (1000-1500 g\\/tonne [ppm by weight]). The vanadium concentration in many crude oils and bitumens is comparable to that in ores. For

D. M. Soskind; V. V. Gribkov; N. P. Slatvinskii-Sidak; M. I. Popov; V. A. Bryukvin; A. G. Vorontnikov

1988-01-01

131

The development of autocatalytic structural materials for use in the sulfur-iodine process for the production of hydrogen  

E-print Network

The Sulfur-Iodine Cycle for the thermochemical production of hydrogen offers many benefits to traditional methods of hydrogen production. As opposed to steam methane reforming - the most prevalent method of hydrogen ...

Miu, Kevin (Kevin K.)

2006-01-01

132

ORIGINAL PAPER Pyrite tracks assimilation of crustal sulfur  

E-print Network

ORIGINAL PAPER Pyrite tracks assimilation of crustal sulfur in Pyrenean peridotites Jean ), consistent with a sedimentary sulfur source. Pyrite microtextures and chalcophile trace element contents support a process of assimilation of crustal sulfur from the metamorphosed sedimentary country rocks

Demouchy, Sylvie

133

[Microbial processes of the carbon and sulfur cycles in the Chukchi Sea].  

PubMed

The research performed in August 2004 within the framework of the Russian-American Long-term Census of the Arctic (RUSALCA) resulted in the first data concerning the rates of the key microbial processes in the water column and bottom sediments of the Bering strait and the Chukchi Sea. The total bacterial counts in the water column varied from 30 x 10(3) cells ml(-1) in the northern and eastern parts to 245 x 10(3) cells ml(-1) in the southern part. The methane content in the water column of the Chukchi sea varied from 8 nmol CH4 l(-1) in the eastern part of the sea to 31 nmol CH4 l(-1) in the northern part of the Herald Canyon. Active microbial processes occurred in the upper 0-3 cm of the bottom sediments; the methane formation rate varied from 0.25 to 16 nmol CH4 dm(-3) day(-1). The rates of methane oxidation varied from 1.61 to 14.7 nmol CH4 dm(-3) day(-1). The rates of sulfate reduction varied from 1.35 to 16.2 micromol SO4(2-) dm(-3) day(-1). The rate of methane formation in the sediments increased with depth, while sulfate reduction rates decreased (less than 1 micromol SO4(2-) dm(-3) day(-1)). These high concentrations of biogenic elements and high rates of microbial processes in the upper sediment layers suggest a specific type of trophic chain in the Chukchi Sea. The approximate calculated balance of methane emission from the water column into the atmosphere is from 5.4 to 57.3 micromol CH4 m(-2) day(-1). PMID:18069330

Savvichev, A S; Rusanov, I I; Pimenov, N V; Zakharova, E E; Veslopolova, E F; Lein, A Iu; Crane, K; Ivanov, M V

2007-01-01

134

Crystallization behaviour of co-sputtered Cu?ZnSnS? precursor prepared by sequential sulfurization processes.  

PubMed

Cu(2)ZnSnS(4) (CZTS) thin films were prepared by the sequential sulfurization of a co-sputtered precursor with a multitarget (Cu, ZnS, and SnS(2)) sputtering system. In order to investigate the crystallization behaviour of the thin films, the precursors were sulfurized in a tube furnace at different temperatures for different time durations. The Raman spectra of the sulfurized thin films showed that their crystallinity gradually improved with an increase in the sulfurization temperature and duration. However, transmission electron microscopy revealed an unexpected result-the precursor thin films were not completely transformed to the CZTS phase and showed the presence of uncrystallized material when sulfurized at 250-400?°C for 60 min and at 500?°C for 30 min. Thus, the crystallization of the co-sputtered precursor thin films showed a strong dependence on the sulfurization temperature and duration. The crystallization mechanism of the precursor thin films was understood on the basis of these results and has been described in this paper. The understanding of this mechanism may improve the standard preparation method for high-quality CZTS absorber layers. PMID:23396187

Han, Junhee; Shin, Seung Wook; Gang, Myeong Gil; Kim, Jin Hyeok; Lee, Jeong Yong

2013-03-01

135

Crystallization behaviour of co-sputtered Cu2ZnSnS4 precursor prepared by sequential sulfurization processes  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) thin films were prepared by the sequential sulfurization of a co-sputtered precursor with a multitarget (Cu, ZnS, and SnS2) sputtering system. In order to investigate the crystallization behaviour of the thin films, the precursors were sulfurized in a tube furnace at different temperatures for different time durations. The Raman spectra of the sulfurized thin films showed that their crystallinity gradually improved with an increase in the sulfurization temperature and duration. However, transmission electron microscopy revealed an unexpected result—the precursor thin films were not completely transformed to the CZTS phase and showed the presence of uncrystallized material when sulfurized at 250-400?°C for 60 min and at 500?°C for 30 min. Thus, the crystallization of the co-sputtered precursor thin films showed a strong dependence on the sulfurization temperature and duration. The crystallization mechanism of the precursor thin films was understood on the basis of these results and has been described in this paper. The understanding of this mechanism may improve the standard preparation method for high-quality CZTS absorber layers.

Han, Junhee; Shin, Seung Wook; Gil Gang, Myeong; Hyeok Kim, Jin; Lee, Jeong Yong

2013-03-01

136

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

137

Sequential nitrification-denitrification process for nitrogenous, sulfurous and phenolic compounds removal in the same bioreactor.  

PubMed

The kinetic and metabolic behavior of an aerobic granular sludge to nitrify, denitrify and nitrify-denitrify was evaluated in batch cultures. In nitrification control, ammonium, 4-methylphenol and sulfide were consumed efficiently (?100%) and recovered as NO3(-), CO2, S(0) and SO4(2-), respectively. In denitrification control, S(0) and nitrate were efficiently consumed and recovered as SO4(2-) and N2, respectively. Sequential nitrification-denitrification process was evaluated by applying oxic/anoxic conditions. Ammonium, 4-methylphenol and sulfide were oxidized to nitrate, CO2 and mainly S(0), respectively, under aerobic conditions. After that, anoxic conditions were established where S(0) reduced all nitrate to N2, with molecular nitrogen yield (YN2) of 1.03 ± 0.06 mg/mg NH4(+)-N consumed. This is the first study to show the capability of an aerobic granular sludge in simultaneous removal of ammonium, 4-methylphenol and sulfide by sequential nitrification-denitrification process in the same bioreactor. PMID:23665217

De la Torre-Velasco, A; Beristain-Cardoso, R; Damian-Matsumura, P; Gómez, J

2013-07-01

138

Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems  

NASA Astrophysics Data System (ADS)

We investigate the relationship between sulfur and oxygen fugacity at Erta Ale and Masaya volcanoes. Oxygen fugacity was assessed utilizing Fe3+/?Fe and major element compositions measured in olivine-hosted melt inclusions and matrix glasses. Erta Ale melts have Fe3+/?Fe of 0.15-0.16, reflecting fO2 of ?QFM 0.0 ± 0.3, which is indistinguishable from fO2 calculated from CO2/CO ratios in high-temperature gases. Masaya is more oxidized at ?QFM +1.7 ± 0.4, typical of arc settings. Sulfur isotope compositions of gases and scoria at Erta Ale (?34Sgas - 0.5‰; ?34Sscoria + 0.9‰) and Masaya (?34Sgas + 4.8‰; ?34Sscoria + 7.4‰) reflect distinct sulfur sources, as well as isotopic fractionation during degassing (equilibrium and kinetic fractionation effects). Sulfur speciation in melts plays an important role in isotope fractionation during degassing and S6+/?S is <0.07 in Erta Ale melt inclusions compared to >0.67 in Masaya melt inclusions. No change is observed in Fe3+/?Fe or S6+/?S with extent of S degassing at Erta Ale, indicating negligible effect on fO2, and further suggesting that H2S is the dominant gas species exsolved from the S2--rich melt (i.e., no redistribution of electrons). High SO2/H2S observed in Erta Ale gas emissions is due to gas re-equilibration at low pressure and fixed fO2. Sulfur budget considerations indicate that the majority of S injected into the systems is emitted as gas, which is therefore representative of the magmatic S isotope composition. The composition of the Masaya gas plume (+4.8‰) cannot be explained by fractionation effects but rather reflects recycling of high ?34S oxidized sulfur through the subduction zone.

Moor, J. M.; Fischer, T. P.; Sharp, Z. D.; King, P. L.; Wilke, M.; Botcharnikov, R. E.; Cottrell, E.; Zelenski, M.; Marty, B.; Klimm, K.; Rivard, C.; Ayalew, D.; Ramirez, C.; Kelley, K. A.

2013-10-01

139

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

140

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

141

Genetic engineering of sulfur-degrading Sulfolobus  

SciTech Connect

The objectives of the proposed research is to first establish a plasmid-mediated genetic transformation system for the sulfur degrading Sulfolobus, and then to clone and overexpress the genes encoding the organic-sulfur-degrading enzymes from Sulfolobus- as well as from other microorganisms, to develop a Sulfolobus-based microbial process for the removal of both organic and inorganic sulfur from coal.

Ho, N.W.Y.

1991-01-01

142

Advanced sulfur control concepts  

SciTech Connect

The primary objective of this study is the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents. Three possible regeneration concepts were identified as a result of a literature search. The potential for elemental sulfur production from a number of candidate metal oxide sorbents using each regeneration concept was evaluated on the basis of a thermodynamic analysis. Two candidate sorbents, Fe{sub 2}O{sub 3} and CeO{sub 2} were chosen for experimental testing. The experimental test program using both electrobalance and fixed-bed reactor sis now getting underway. The objective is to determine reaction conditions--temperature, pressure, space velocity, and regeneration feed gas composition--which will maximize the yield of elemental sulfur in the regeneration product gas. Experimental results are to be used to define a conceptual desulfurization-regeneration process and to provide a preliminary economic evaluation.

Harrison, D.P.; Lopez-Ortiz, A.; White, J.D.; Groves, F.R. Jr.

1995-11-01

143

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

144

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report for April-June 1984. [Sulfidic, polysulfidic, thiosulfate, sulfite, sulfate, thiocyanate  

SciTech Connect

Task 1: methods development for the speciation of the polysulfides. Work on this task has been completed in December 1983 and reported accordingly in DOE/PC/40783-T13. Task 2: methods development for the speciation of dithionite and polythionates. Electrochemical reduction of tetrathionate and pentathionate at the dropping mercury electrode (DME) proceeds through a mechanism involving specific adsorption of the reactant at the DME surface and yielding polarographic waves at -0.2 volt (versus the saturated calomel electrode) in aqueous solution. Ethanol interferes with the specific adsorption of tetrathionate and pentathionate in a range of potentials between 0.0 and -1.1 volt, because EtOH is preferentially adsorbed. This results in a shift of the polarographic half-wave potentials of tetrathionate and pentathionate, which facilitates their determination in polythionate mixtures. On the other hand, the polarographic reduction of trithionate is unaffected by ethanol, because it occurs at -1.5 volt where ethanol is not adsorbed at the surface of the DME. Task 3: total accounting of the sulfur balance in representative samples of synfuel process streams. Analyses of two aqueous gasifier effluents from Grand Forks, ND, were performed. An untreated specimen contained sulfidic and polysulfidic sulfur, thiosulfate and thiocyanate. On the other hand, sulfite, sulfate, and thiocyanate were the only sulfur moieties observed in the Grand Forks sample which had been stripped at PETC. 7 references, 1 figure, 3 tables.

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

1984-07-01

145

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

146

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

147

Hydrogen and Sulfur Production from Hydrogen Sulfide Wastes  

E-print Network

, this novel process recovers both hydrogen and sulfur. The plasma process involves dissociating hydrogen sulfide in a "nonequilibrium" plasma in a microwave or radio-frequency reactor. After the dissociation process, sulfur is condensed and sold just...

Harkness, J.; Doctor, R. D.

148

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

149

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

150

Uses of lunar sulfur  

SciTech Connect

Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical and biochemical properties. Although low in abundance on the Moon (/approximately/0.1% in mare soils), sulfur is surface-correlated and relatively extractable. Co-production of sulfur during oxygen extraction from ilmenite-rich soils could yield sulfur in masses up to 10% of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource. 29 refs., 3 figs.

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

1988-01-01

151

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

152

Stable isotope compositions of serpentinite seamounts in the Mariana forearc: Serpentinization processes, fluid sources and sulfur metasomatism  

USGS Publications Warehouse

The Mariana and Izu-Bonin arcs in the western Pacific are characterized by serpentinite seamounts in the forearc that provide unique windows into the mantle wedge. We present stable isotope (O, H, S, and C) data for serpentinites from Conical seamount in the Mariana forearc and S isotope data for Torishima seamount in the Izu-Bonin forearc in order to understand the compositions of fluids and temperatures of serpentinization in the mantle wedge, and to investigate the transport of sulfur from the slab to the mantle wedge. Six serpentine mineral separates have a restricted range of ??18O (6.5-8.5???). Antigorite separates have ??D values of -29.5??? to -45.5??? that reflect serpentinization within the mantle wedge whereas chrysotile has low ??D values (-51.8??? to -84.0???) as the result of re-equilibration with fluids at low temperatures. Fractionation of oxygen isotopes between serpentine and magnetite indicate serpentinization temperatures of 300-375 ??C. Two late cross-fiber chrysotile veins have higher ??18O values of 8.9??? to 10.8??? and formed at lower temperatures (as low as ???100 ??C). Aqueous fluids in equilibrium with serpentine at 300-375 ??C had ??18O = 6.5-9??? and ??D = -4??? to -26???, consistent with sediment dehydration reactions at temperatures <200 ??C in the subducting slab rather than a basaltic slab source. Three aragonite veins in metabasalt and siltstone clasts within the serpentinite flows have ??18O = 16.7-24.5???, consistent with the serpentinizing fluids at temperatures <250 ??C. ??13C values of 0.1-2.5??? suggest a source in subducting carbonate sediments. The ??34S values of sulfide in serpentinites on Conical Seamount (-6.7??? to 9.8???) result from metasomatism through variable reduction of aqueous sulfate (??34S = 14???) derived from slab sediments. Despite sulfur metasomatism, serpentinites have low sulfur contents (generally < 164 ppm) that reflect the highly depleted nature of the mantle wedge. The serpentinites are mostly enriched in 34S (median ??34Ssulfide = 4.5???), consistent with a 34S-enriched mantle wedge as inferred from arc lavas. ?? 2006 Elsevier B.V. All rights reserved.

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

2006-01-01

153

Sulfur minimization in bacterial leaching  

SciTech Connect

The production of sewage biosolids in Ontario in 1989 was estimated to be 7 million m{sup 3} of wet sludge per year. Of this amount, land application accounts for between 20 and 30% of the total. Unfortunately, the use of sewage biosolids on agricultural land is often prohibited because of heavy metal contamination of the biosolids. High cost and operational problems have made chemical methods of metal extraction unattractive. Consequently, microbiological methods of leaching of heavy metals have been studied for over a decade. A relatively simple microbiological process has been investigated in recent years in flask level experiments and recently in a semicontinuous system. The process exploits nonacidophilic and acidophilic indigenous thiobacilli to extract heavy metals from sewage biosolids. These thiobacilli use elemental sulfur as the energy source, producing sulfuric acid. However, the resulting decontaminated biosolids can cause environmental problems like acidification of the soil, when acid is generated from the residual sulfur in the biosolids. The present study examines the possibility of reducing the amount of sulfur added in batch and semicontinuous bacterial leaching systems, and maximizing sulfur oxidation efficiency, thereby reducing the residual sulfur in leached biosolids.

Seth, R.; Prasad, D.; Henry, J.G. [Univ. of Toronto, Ontario (Canada). Dept. of Civil Engineering

1996-11-01

154

Modeling the fate of atmospheric reduced nitrogen during the Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS): Performance evaluation and diagnosis using integrated processes rate analysis  

NASA Astrophysics Data System (ADS)

Excess wet and dry deposition of nitrogen-containing compounds is a concern at a number of national parks. The Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS) was conducted during the spring and summer of 2006 to identify the overall mix of ambient and deposited sulfur and nitrogen at Rocky Mountain National Park (RMNP), in north-central Colorado. The Comprehensive Air Quality Model with extensions (CAMx) was used to simulate the fate of gaseous and particulate species subjected to multiple chemical and physical processes during RoMANS. This study presents an operational evaluation with a special emphasis on the model performance of reduced nitrogen species. The evaluation showed large negative biases and errors at RMNP and the entire domain for ammonia; therefore the model was considered inadequate for future source apportionment applications. The CAMx Integrated Processes Rate (IPR) analysis tool was used to elucidate the potential causes behind the poor model performance. IPR served as a tool to diagnose the relative contributions of individual physical and chemical processes to the final concentrations of reduced nitrogen species. The IPR analysis revealed that dry deposition is the largest sink of ammonia in the model, with some cells losing almost 100% of the available mass. Closer examination of the ammonia dry deposition velocities in CAMx found that they were up to a factor of 10 larger than those reported in the literature. A series of sensitivity simulations were then performed by changing the original deposition velocities with a simple multiplicative scaling factor. These simulations showed that even when the dry deposition values were altered to reduce their influence, the model was still unable to replicate the observed time series; i.e., it fixed the average bias, but it did not improve the precision.

Rodriguez, Marco A.; Barna, Michael G.; Gebhart, Kristi A.; Hand, Jennifer L.; Adelman, Zachariah E.; Schichtel, Bret A.; Collett, Jeffrey L., Jr.; Malm, William C.

2011-01-01

155

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

156

Microbial stabilization of sulfur-laden sorbents. [Quarterly] technical report, March 1, 1993May 31, 1993  

Microsoft Academic Search

Clean coal technologies that involve limestone for in situ 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 frequently results in undesirable release of SOâ.

1993-01-01

157

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

Microsoft Academic Search

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

Myunghun Lee

2005-01-01

158

40 CFR 436.190 - Applicability; description of the Frasch sulfur subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the Frasch sulfur subcategory. 436.190 Section...PROCESSING POINT SOURCE CATEGORY Frasch Sulfur Subcategory § 436.190 Applicability; description of the Frasch sulfur subcategory. The provisions of...

2010-07-01

159

40 CFR 436.190 - Applicability; description of the Frasch sulfur subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the Frasch sulfur subcategory. 436.190 Section...PROCESSING POINT SOURCE CATEGORY Frasch Sulfur Subcategory § 436.190 Applicability; description of the Frasch sulfur subcategory. The provisions of...

2011-07-01

160

40 CFR 436.190 - Applicability; description of the Frasch sulfur subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the Frasch sulfur subcategory. 436.190 Section...PROCESSING POINT SOURCE CATEGORY Frasch Sulfur Subcategory § 436.190 Applicability; description of the Frasch sulfur subcategory. The provisions of...

2013-07-01

161

40 CFR 436.190 - Applicability; description of the Frasch sulfur subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the Frasch sulfur subcategory. 436.190 Section...PROCESSING POINT SOURCE CATEGORY Frasch Sulfur Subcategory § 436.190 Applicability; description of the Frasch sulfur subcategory. The provisions of...

2012-07-01

162

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

163

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

164

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

165

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

166

MVC: A user-based on-line optimal control system for gas processing and treating plants. Development and results for claus sulfur recovery and sweetening modules. Topical report, June 1992-September 1993  

SciTech Connect

The objective of this project was to develop and field validate modular, on-line, advanced control systems to optimize the operation of Claus sulfur recovery and sweetening in gas processing plants with emphasis on small and mid-sized facilities.

Berkowitz, P.N.; Papadopoulos, M.N.; Colwell, L.W.; Poe, W.; Yiu, Y.

1993-09-01

167

Process for cleaning and removal of sulfur compounds from low Btu fuel gases. Interim report, January--March 1976  

Microsoft Academic Search

It is proposed to remodel the PDU by incorporation of appropriate sub-systems to permit operation in continuous process mode. The PDU will be operated for a period of time sufficient to demonstrate process viability. It has been relocated to an inproved support facility and repaired to a state of near readiness for operation. During early pilot plant operation relatively high

R. H. Moore; D. C. Ham; G. E. Stegen

1976-01-01

168

Utilization of Battelle-treated coal in gasification and combustion processes to control sulfur emissions. Final report  

Microsoft Academic Search

The purpose of the study was to provide an evaluation of the environmental and associated economic advantages of using a coal treated by a process developed by Battelle as a feedstock for: (1) a new partial oxidation\\/combustion process; (2) commercially available fixed-bed gasifiers; and (3) utility combustors. Findings confirm the technical and economic feasibility of using Battelle Treated Coal (BTC)

H. N. Conkle; H. F. Feldmann; A. Levy; E. L. Merryman; D. R. Hopper; O. J. Hahn

1982-01-01

169

Development of infrared methods for characterization of inorganic sulfur species related to injection desulfurization processes. Final report, December 1985-June 1988  

SciTech Connect

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 SO{sub 2} and alkaline earth compounds and are called flue gas desulfurization (FGD) processes. Of these methods, dry desulfurization processes, using fine particulate limestone, have emerged as the preferred technology for future SO{sub 2} emission control. The development of a reliable in situ spectroscopic technique for studying heterogeneous reactions, such as those occurring in FGD systems, is the key to understanding the surface mechanisms which control these reactions. The report covers the development and application of Fourier transform infrared spectrometry with photacoustic and diffuse reflectance detection for this purpose. The specific reactions chosen for study are those of SO{sub 2} with CaO, CaCO{sub 3} and Ca(OH){sub 2}. The project evaluates the feasibility of using these infrared spectroscopic techniques to monitor reactions between limestone and related materials with SO{sub 2} at various temperatures so as to aid in obtaining a clear understanding of the chemical mechanisms by which SO{sub 2} is captured.

Thompson, M.M.; Palmer, R.A.

1990-05-01

170

The Sulfur Cycle  

ERIC Educational Resources Information Center

A model estimating the contributions of sulfur compounds by natural and human activities, and the rate of removal of sulfur from the atmosphere, is based on a review of the existing literature. Areas requiring additional research are identified. (AL)

Kellogg, W. W.; And Others

1972-01-01

171

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

172

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...

173

Chemically Active Fluid-Bed process for sulfur removal during gasification of carbonaceous fuels. Final report, May 1976May 1979  

Microsoft Academic Search

This report covers the final 3 years of a 9-year program to evaluate the Chemically Active Fluid Bed (CAFB) process for gasification and desulfurization of liquid and solid fuels in a fluidized bed of hot lime. A range of alternative fuels, including three coals and a lignite, were gasified in a 3-MWt pilot-scale gasifier, and small-scale batch tests were conducted,

Kowszun

1987-01-01

174

Effects of Cu/In ratio of electrodeposited precursor on post-sulfurization process in fabricating quaternary CuIn(S,Se) 2 thin films  

NASA Astrophysics Data System (ADS)

This paper reports the analysis of S diffusion into electrodeposited CuInSe 2 (CISe) precursors during post-sulfurization treatment at 500 °C in an Ar/H 2S ambient. The characterizations of the sulfurized films by X-ray diffraction, grazing-incidence X-ray diffraction, Auger electron spectroscopy and micro-Raman spectroscopy allow the observation of the strong dependence of S incorporation into these films on the Cu/In ratio of the precursor. AES profiles reveal higher S content along the depth of Cu-rich film than Cu-poor film after sulfurization. Raman Scattering shows that copper sulfoselenides Cu-(Se,S) are only detected in Cu-rich samples. The re-crystallization of films during sulfurization was analyzed and it is presumed that quasi-liquid Cu-Se phases, which are related to Cu/In ratio of precursor, promote continuous incorporation of S into these films.

Lai, Yanqing; Kuang, Sanshuang; Liu, Fangyang; Yuan, Zhixue; Zhang, Zhian; Li, Yi; Liu, Jun; Wang, Bo; Tang, Ding; Li, Jie; Liu, Yexiang

2011-08-01

175

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

176

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

177

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

1988-02-01

178

Sulfur in achondritic meteorites.  

PubMed

Total sulfur abundances have been measured for 48 achondrites. For twenty eucrites they ranged from 370 to 3700 micrograms S/g with a median sulfur content of 1180 micrograms S/g. Sulfur abundances for howardites ranged from 1490 to 3240 micrograms S /g and had a median sulfur concentration of 2340 micrograms S/g. Diogenites' sulfur abundances ranged from 130 to 3170 micrograms S/g, with a median value of 1280 micrograms S/g. Four shergottites had a median sulfur content of 1940 micrograms S/g and ranged from 740 to 2540 micrograms S/g. Enstatite achondrites contained the greatest sulfur abundances of any achondrite group. They ranged from 2450 to 8580 micrograms S/g and had a median sulfur content of 6020 micrograms S/g and had a median sulfur content of 6020 micrograms S/g. A single Chassignite had a sulfur concentration of 360 micrograms S/g. The wide variations in sulfur concentrations for the achondrites reflect the small scale heterogeneous nature of these unique extraterrestrial materials due in large part to discrete sulfide mineral grains. PMID:11539026

Gibson, E K; Moore, C B; Primus, T M; Lewis, C F

1985-09-30

179

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

180

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

181

Sulfur isotopic analysis of individual organosulfur compounds from Cariaco Basin  

NASA Astrophysics Data System (ADS)

Organic matter sulfurization reactions in marine sediments influence global cycles of carbon, oxygen, and sulfur. We investigated sulfurization processes by exploiting the sulfur isotopic gradient generated by microbial sulfate reduction. A novel analytical method, coupled GC-ICPMS, provides a previously inaccessible level of information about the controls, mechanisms, and sulfur sources for organic sulfur compound (OSC) formation. Lipids were extracted from eight depths in a six-meter-long sediment core from the Cariaco Basin. The polar fractions of these complex extracts contained individual OSC with ?34S values ranging from -37.0 to -20.9‰. The average standard deviation for triplicate analyses was approximately 1.5‰. Organosulfur compounds are more isotopically depleted than coexisting sulfide and represent the most depleted component of the Cariaco sulfur system yet observed. Extreme 34S depletions may record significant syngenetic OSC formation in a zone of intensive sulfur recycling near either the sediment-water interface or in the water column. OSC ?34S trends with depth indicate the onset of sulfurization between 140 and 265 cm; apparent diagenetic OSC formation continues to at least 535 cm, beyond the previously described sulfurization window for some non-polar compounds. Diverse ?34S values for OSC also provide important constraints on the diagenetic histories of different compounds and may record reaction with distinct inorganic sulfur pools. These results will be presented in the context of available inorganic and organic geochemical data to describe the processes of organic sulfurization in marine environments.

Raven, M. R.; Sessions, A. L.; Adkins, J. F.

2012-12-01

182

Sulfite oxidation in the purple sulfur bacterium Allochromatium vinosum: identification of SoeABC as a major player and relevance of SoxYZ in the process.  

PubMed

In phototrophic sulfur bacteria, sulfite is a well-established intermediate during reduced sulfur compound oxidation. Sulfite is generated in the cytoplasm by the reverse-acting dissimilatory sulfite reductase DsrAB. Many purple sulfur bacteria can even use externally available sulfite as a photosynthetic electron donor. Nevertheless, the exact mode of sulfite oxidation in these organisms is a long-standing enigma. Indirect oxidation in the cytoplasm via adenosine-5'-phosphosulfate (APS) catalysed by APS reductase and ATP sulfurylase is neither generally present nor essential. The inhibition of sulfite oxidation by tungstate in the model organism Allochromatium vinosum indicated the involvement of a molybdoenzyme, but homologues of the periplasmic molybdopterin-containing SorAB or SorT sulfite dehydrogenases are not encoded in genome-sequenced purple or green sulfur bacteria. However, genes for a membrane-bound polysulfide reductase-like iron-sulfur molybdoprotein (SoeABC) are universally present. The catalytic subunit of the protein is predicted to be oriented towards the cytoplasm. We compared the sulfide- and sulfite-oxidizing capabilities of A. vinosum WT with single mutants deficient in SoeABC or APS reductase and the respective double mutant, and were thus able to prove that SoeABC is the major sulfite-oxidizing enzyme in A. vinosum and probably also in other phototrophic sulfur bacteria. The genes also occur in a large number of chemotrophs, indicating a general importance of SoeABC for sulfite oxidation in the cytoplasm. Furthermore, we showed that the periplasmic sulfur substrate-binding protein SoxYZ is needed in parallel to the cytoplasmic enzymes for effective sulfite oxidation in A. vinosum and provided a model for the interplay between these systems despite their localization in different cellular compartments. PMID:24030319

Dahl, Christiane; Franz, Bettina; Hensen, Daniela; Kesselheim, Anne; Zigann, Renate

2013-12-01

183

Io - Geochemistry of sulfur  

NASA Technical Reports Server (NTRS)

The evidence from Voyager imaging, Earth-based spectral reflectivity studies, and thermal emission measurements combine to suggest an extremely fresh, volcanically recycled sulfur-rich crust for Io, with very shallow large-scale melting. Two present styles of volcanism are possible, depending on the thickness of local deposits of sulfur: shallow liquid sulfur magma generation with quiescent flooding, and high-temperature volcanism with violet eruption of a sulfur-iron magma driven by SO2. Evolutionary considerations preclude direct derivation of Io's lithosphere from any metal-bearing chondritic source material. Metal-free C3V- or C2M-type parent material of either primary or secondary origin is the most plausible direct antecedent of the present sulfur-rich crust. Sulfates are almost certainly important constituents of the mantle, and can participate in the recycling of reduced, dense sulfide species to prevent total extraction of sulfur into the core.

Lewis, J. S.

1982-01-01

184

Dual protection of sulfur by carbon nanospheres and graphene sheets for lithium-sulfur batteries.  

PubMed

Well-confined elemental sulfur was implanted into a stacked block of carbon nanospheres and graphene sheets through a simple solution process to create a new type of composite cathode material for lithium-sulfur batteries. Transmission electron microscopy and elemental mapping analysis confirm that the as-prepared composite material consists of graphene-wrapped carbon nanospheres with sulfur uniformly distributed in between, where the carbon nanospheres act as the sulfur carriers. With this structural design, the graphene contributes to direct coverage of sulfur to inhibit the mobility of polysulfides, whereas the carbon nanospheres undertake the role of carrying the sulfur into the carbon network. This composite achieves a high loading of sulfur (64.2?wt?%) and gives a stable electrochemical performance with a maximum discharge capacity of 1394?mAh?g(-1) at a current rate of 0.1?C as well as excellent rate capability at 1?C and 2?C. The improved electrochemical properties of this composite material are attributed to the dual functions of the carbon components, which effectively restrain the sulfur inside the carbon nano-network for use in lithium-sulfur rechargeable batteries. PMID:24692070

Wang, Bei; Wen, Yanfen; Ye, Delai; Yu, Hua; Sun, Bing; Wang, Guoxiu; Hulicova-Jurcakova, Denisa; Wang, Lianzhou

2014-04-25

185

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

186

Apparatus for recovery of sulfur  

SciTech Connect

This patent describes an apparatus for the recovery of sulfur from an underground sulfur formation. It comprises means for the injection of hot water into contact with the underground sulfur formation; means to permit the water and elemental sulfur to remain in contact, so as to melt at least a portion of the sulfur and form a mixture of molten sulfur and water; means for removing the mixture of molten sulfur and heated water to the surface; means for separating the water and sulfur mixture to recover molten sulfur and water; and means to recycle the water to the underground formation.

Peters, J.R.; Ramey, M.E.; Seyffert, A.E.; Canon, J.L.; Robinson, M.W.; Abercrombie, W.T.

1989-09-26

187

Sodium-sulfur thermal battery  

Microsoft Academic Search

This paper discusses a sodium-sulfur thermal battery for generating electrical energy at temperatures above the melting point of sodium metal and sulfur. It comprises a sodium electrode comprising sodium metal; a sulfur electrode comprising sulfur; and a separator located between the sodium and sulfur electrodes. The separator having sufficient porosity to allow preliminary migration of fluid sodium metal and fluid

Ludwig

1990-01-01

188

Development of a zero-emissions sulfur-recovery process: 1. Thermochemistry and reaction kinetics of mixtures of H[sub 2]S and CO[sub 2] at high temperature  

SciTech Connect

When hydrogen sulfide is heated above 600 C in the presence of carbon dioxide, the conversion of H[sub 2]S to elemental sulfur is greater than when hydrogen sulfide is heated alone. Formation of elemental sulfur is favored by high temperature, low pressure, and low water content in the gas. The rate-limiting step is the thermal dissociation of H[sub 2]S. The hydrogen then equilibrates rapidly with CO[sub 2], forming CO and H[sub 2]O via the water-gas-shift reaction. The equilibrium of H[sub 2]S dissociation is therefore shifted to favor the formation of elemental sulfur. The main byproduct is COS, which is formed by a reaction between CO[sub 2] and H[sub 2]S that is analogous to the water-gas-shift reaction. A quench rate of 1,000 C/s or greater is sufficient to prevent loss of elemental sulfur by back-reaction or reaction to COS during cooling. Formation of small amounts Of SO[sub 2] and CS[sub 2] is thermodynamically feasible but has not been observed. Molybdenum disulfide is the best catalyst for H[sub 2]S dissociation of those discussed in the literature. A process based on this chemistry has significant advantages over the Claus process in that it need not produce any tail gas, it allows recovery of the chemical (or fuel) value of the hydrogen from the H[sub 2]S, and it requires much less stringent process control.

Towler, G.P.; Lynn, S. (Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering)

1993-11-01

189

Optimization of wastewater feeding for single-cell protein production in an anaerobic wastewater treatment process utilizing purple non-sulfur bacteria in mixed culture condition  

Microsoft Academic Search

Impacts of operation timing of feeding and withdrawal on anaerobic wastewater treatment utilizing purple non-sulfur bacteria have been investigated in mixed culture condition with acidogenic bacteria. Simulated wastewater containing glucose was treated in a laboratory-scale chemostat reactor, changing the timing of wastewater feeding and withdrawal. Rhodopseudomonas palustris, which does not utilize glucose as a substrate, was inoculated in the reactor.

Ryo Honda; Kensuke Fukushi; Kazuo Yamamoto

2006-01-01

190

Determination of free sulfites (SO3-2) in dried fruits processed with sulfur dioxide by ion chromatography through anion exchange column and conductivity detection.  

PubMed

A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and effective for the determination of high levels of sulfites in dried fruits. PMID:24282955

Liao, Benjamin S; Sram, Jacqueline C; Files, Darin J

2013-01-01

191

World sulfur production: Petroleum derived as of January 1, 1996  

SciTech Connect

Data are presented on world sulfur production by company within each country. The table lists the source of the sulfur (refinery gases, natural gas, acid gas, sour gas, oil sands, associated gas, or resid asphalt), the type of process used to recovery the sulfur, plant design capacity, and production. Processes include Claus, chlorination, Scot, Sulfinol, Sulfreen, modified Claus, bed absorption, MDEA-LoCat, Selectox, Parsons, SNEA, Comprimo, Uhde, Stretford, and Wellman-Lord.

NONE

1996-07-01

192

Nanostructured sulfur cathodes.  

PubMed

Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. PMID:23325336

Yang, Yuan; Zheng, Guangyuan; Cui, Yi

2013-04-01

193

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

NASA Astrophysics Data System (ADS)

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 of sulfate anion production for cyclo-octal sulfur grains in frozen water at temperatures, energies, and dose rates appropriate for Europa using energetic electrons. The measured rate is GMixture(SO42-)=fSulfur (r0/r)?G1 molecules (100 eV)-1, where fSulfur is the sulfur weight fraction, r is the grain radius, r0=50 ?m, ??1.9, and G1=0.4±0.1. Equilibrium column densities N are derived for Europa's surface and follow the ordering N(H2SO4) » N(S)>N(SO2)>N(H2S). The lifetime of a sulfur atom on Europa's surface for radiolysis to H2SO4 is ?(-S)=120(r/r0)? years. Rapid radiolytic processing hides the identity of the original source of the sulfurous material, but Iogenic plasma ion implantation and an acidic or salty ocean are candidate sources. Sulfate salts, if present, would be decomposed in <3800 years and be rapidly assimilated into the sulfur cycle.

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

2002-06-01

194

Competitive Carbon-Sulfur vs Carbon-Carbon Bond Activation of 2-Cyanothiophene with [Ni(dippe)H]2  

E-print Network

Competitive Carbon-Sulfur vs Carbon-Carbon Bond Activation of 2-Cyanothiophene with [Ni(dippe)H]2 Hydrodesulfurization (HDS) is the process by which sulfur is removed from hydrocarbons during the refinement of petroleum. Failure to remove sulfur during this process results in the formation of noxious sulfur oxides

Jones, William D.

195

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

196

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

197

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

198

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

199

Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes  

USGS Publications Warehouse

The sulfur geochemistry of the lacustrine Paleogene Green River Formation (Colorado, Utah, and Wyoming, USA) is unlike that of most marine and other lacustrine rocks. Distinctive chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides strikingly enriched in 34S, cyclical trends in sulfur abundance and ??34S values, and long-term evolutionary trends in ??34S values. Analyses that identified and quantified these characteristics include carbonate-free abundance of organic carbon (0.13-47 wt%), total iron (0.31-13 wt%), reactive iron (>70% of total iron), total sulfur (0.02-16 wt%), acid-volatile monosulfide (SAv), disulfide (SDi > 70% of total sulfur), sulfate (SSO4) and organosulfur (SOrg); isotopic composition of separated sulfur phases (??34SDi,Av up to +49???); and mineralogy, morphology and paragenesis of sulfide minerals. Mineralogy, morphology, ??34SDi,Av, and ??34SOrg have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H2S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H2S:SO4 ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H2S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to ??34S values much greater than that of inflow sulfate, which is estimated to have been +20??? A six-million-year interval within Lake Uinta cores records this evolution as well as smaller systematic changes in ??34S, interpreted to reflect ~ 100,000-year lake-level cycles. When porewater was exceptionally reducing, unstable FeS phases eventually recrystallized to pyrrhotite during diagenesis. A much later reaction related to weathering altered pyrrhotite to marcasite. ?? 1993.

Tuttle, M.L.; Goldhaber, M.B.

1993-01-01

200

Oxygen and sulfur isotope fractionation during anaerobic bacterial disproportionation of elemental sulfur  

Microsoft Academic Search

Bacterial disproportionation of elemental sulfur is an important process in the sulfur cycle of natural sediments and leads to the formation of hydrogen sulfide and sulfate. The oxygen atoms in sulfate during this anaerobic process are completely derived from water according to the overall reaction: 4H2O + 4S0 ? 3H2S + SO42? + 2H+In the present study, stable oxygen isotope

M. E. Böttcher; B. Thamdrup; T. W. Vennemann

2001-01-01

201

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

202

Sulfur volcanoes on Io?  

NASA Technical Reports Server (NTRS)

The unusual rheological properties of sulfur are discussed in order to determine the distinctive volcanic flow morphologies which indicate the presence of sulfur volcanoes on the Saturnian satellite Io. An analysis of high resolution Voyager imagery reveals three features which are considered to be possible sulfur volcanoes: Atar Patera, Daedalus Patera, and Kibero Patera. All three features are distinguished by circular-to-oval central masses surrounded by irregular widespread flows. The central zones of the features are interpreted to be domes formed of high temperature sulfur. To confirm the interpretations of the satellite data, molten sulfur was extruded in the laboratory at a temperature of 210 C on a flat surface sloping 0.5 deg to the left. At this temperature, the sulfur formed a viscous domelike mass over the event. As parts of the mass cooled to 170 C the viscosity decreased to a runny stage, forming breakout flows. It is concluded that a case can be made for sulfur volcanoes on Io sufficient to warrant further study, and it is recommended that the upcoming Galileo mission examine these phenomena.

Greeley, R.; Fink, J. H.

1984-01-01

203

Are we getting enough sulfur in our diet?  

PubMed Central

Sulfur, after calcium and phosphorus, is the most abundant mineral element found in our body. It is available to us in our diets, derived almost exclusively from proteins, and yet only 2 of the 20 amino acids normally present in proteins contains sulfur. One of these amino acids, methionine, cannot be synthesized by our bodies and therefore has to be supplied by the diet. Cysteine, another sulfur containing amino acid, and a large number of key metabolic intermediates essential for life, are synthesized by us, but the process requires a steady supply of sulfur. Proteins contain between 3 and 6% of sulfur amino acids. A very small percentage of sulfur comes in the form of inorganic sulfates and other forms of organic sulfur present in foods such as garlic, onion, broccoli, etc. The minimal requirements (RDA) for all the essential amino acids have always been estimated in terms of their ability to maintain a nitrogen balance. This method asses amino acid requirements for protein synthesis, only one of the pathways that methionine follows after ingestion. To adequately evaluate the RDA for methionine, one should perform, together with a nitrogen balance a sulfur balance, something never done, neither in humans nor animals. With this in mind we decided to evaluate the dietary intake of sulfur (as sulfur amino acids) in a random population and perform sulfur balance studies in a limited number of human volunteers. Initially this was done to try and gain some information on the possible mode of action of a variety of sulfur containing compounds (chondroitin sulfate, glucosamine sulfate, and others, ) used as dietary supplements to treat diseases of the joints. Out of this study came information that suggested that a significant proportion of the population that included disproportionally the aged, may not be receiving sufficient sulfur and that these dietary supplements, were very likely exhibiting their pharmacological actions by supplying inorganic sulfur. PMID:17986345

Nimni, Marcel E; Han, Bo; Cordoba, Fabiola

2007-01-01

204

Active Microbial Sulfur Disproportionation in  

E-print Network

Active Microbial Sulfur Disproportionation in the Mesoproterozoic David T. Johnston,1 *. Boswell A E. Canfield5 The environmental expression of sulfur compound disproportionation has been placed sulfur isotope 33S. These measurements imply that sulfur compound disproportionation was an active part

Long, Bernard

205

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

206

Removal of sulfur compounds from combustion product exhaust  

DOEpatents

A method and device are disclosed for removing sulfur containing contaminents from a combustion product exhaust. The removal process is carried out in two stages wherein the combustion product exhaust is dissolved in water, the water being then heated to drive off the sulfur containing contaminents. The sulfur containing gases are then resolublized in a cold water trap to form a concentrated solution which can then be used as a commercial product.

Cheng, Dah Y. (Palo Alto, CA)

1982-01-01

207

Under sulfur's spell  

NASA Astrophysics Data System (ADS)

Thomas Rauchfuss marvels at the diversity of sulfur reactivity. Although it poisons most industrial catalysts, it adopts many forms in nature and takes on a variety of biological roles -- including that of a biocatalyst.

Rauchfuss, Thomas

2011-08-01

208

No sulfur flows on Io  

NASA Technical Reports Server (NTRS)

Physical and chemical properties of elemental sulfur are incompatible with the suggestion that the colored flows associated with volcanoes on Io are quenched unstable allotropes of sulfur. Either the volcanic flows are not sulfur, or some mechanism other than quenching is required to produce colored forms of sulfur in them. The properties of sulfur are unsuited to the production and survival of colored unstable allotropes on Io. The color of this object is probably due to some other material, possibly iron compounds.

Young, A. T.

1984-01-01

209

Two-step rapid sulfur capture. Final report  

SciTech Connect

The primary goal of this program was to test the technical and economic feasibility of a novel dry sorbent injection process called the Two-Step Rapid Sulfur Capture process for several advanced coal utilization systems. The Two-Step Rapid Sulfur Capture process consists of limestone activation in a high temperature auxiliary burner for short times followed by sorbent quenching in a lower temperature sulfur containing coal combustion gas. The Two-Step Rapid Sulfur Capture process is based on the Non-Equilibrium Sulfur Capture process developed by the Energy Technology Office of Textron Defense Systems (ETO/TDS). Based on the Non-Equilibrium Sulfur Capture studies the range of conditions for optimum sorbent activation were thought to be: activation temperature > 2,200 K for activation times in the range of 10--30 ms. Therefore, the aim of the Two-Step process is to create a very active sorbent (under conditions similar to the bomb reactor) and complete the sulfur reaction under thermodynamically favorable conditions. A flow facility was designed and assembled to simulate the temperature, time, stoichiometry, and sulfur gas concentration prevalent in the advanced coal utilization systems such as gasifiers, fluidized bed combustors, mixed-metal oxide desulfurization systems, diesel engines, and gas turbines.

NONE

1994-04-01

210

Method for manufacture of ammonium thiosulfate from ammonia and solid sulfur or HâS rich gas stream and\\/or both solid sulfur and HâS gas streams  

Microsoft Academic Search

A process for the manufacture of aqueous ammonium thiosulfate from sulfur dioxide wherein ammonium sulfite is formed as an intermediate product by the scrubbing reaction of ammonia with sulfur dioxide in the presence of water. Preferably, the ammonia is added to the sulfur dioxide in the bottom of the second scrubbing reaction vessel so as to maintain the sulfur dioxide

Ott

1984-01-01

211

The Biogeochemistry of Sulfur in Hydrothermal Systems  

NASA Technical Reports Server (NTRS)

The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in hydrothermal systems. The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in hydrothermal systems. Understanding how sulfur became prevalent in biochemical processes and many biomolecules requires knowledge of the reaction properties of sulfur-bearing compounds. We have previously estimated thermodynamic data for thiols, the simplest organic sulfur compounds, at elevated temperatures and pressures. If life began in hydrothermal environments, it is especially important to understand reactions at elevated temperatures among sulfur-bearing compounds and other organic molecules essential for the origin and persistence of life. Here we examine reactions that may have formed amino acids with thiols as reaction intermediates in hypothetical early Earth hydrothermal environments. (There are two amino acids, cysteine and methionine, that contain sulfur.) Our calculations suggest that significant amounts of some amino acids were produced in early Earth hydrothermal fluids, given reasonable concentrations H2, NH3, H2S and CO. For example, preliminary results indicate that glycine activities as high as 1 mmol can be reached in these systems at 100 C. Alanine formation from propanethiol is also a favorable reaction. On the other hand, the calculated equilibrium log activities of cysteine and serine from propanethiol are -21 and -19, respectively, at 100 C. These results indicate that while amino acid formation with thiols as intermediates is favored in some cases, other mechanisms may have been necessary to produce significant amounts of other amino acids. Coupled with our previous results for thiols, these studies imply that sulfur may have been easily incorporated into the organic geochemistry of early Earth hydrothermal systems, leading to its widespread use in biomolecules. Formation of more complex biomolecules in hydrothermal systems may have required sulfur-bearing organic compounds as reaction intermediates.

Schulte, Mitchell; Rogers, K. L.; DeVincenzi, Donald L. (Technical Monitor)

2001-01-01

212

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

213

In situ monitoring of sulfuric acid decomposition by Fourier transform infrared (FT-IR) spectroscopy in the sulfur iodine thermochemical reaction for the production of hydrogen  

Microsoft Academic Search

A potential way to produce large amounts of hydrogen for energy needs is the thermal breakdown of sulfuric acid (H2SO4) to oxygen, water, and sulfur dioxide (SO2). The sulfur dioxide can then be reacted with iodide to produce hydrogen iodide and ultimately hydrogen. In order to maximize the efficiency of the process it would be ideal to make in situ

Dion Rivera

2005-01-01

214

Quantitative proteomics of Chlorobaculum tepidum: insights into the sulfur metabolism of a phototrophic green sulfur bacterium.  

PubMed

Chlorobaculum (Cba.) tepidum is a green sulfur bacterium that oxidizes sulfide, elemental sulfur, and thiosulfate for photosynthetic growth. To gain insight into the sulfur metabolism, the proteome of Cba. tepidum cells sampled under different growth conditions has been quantified using a rapid gel-free, filter-aided sample preparation (FASP) protocol with an in-solution isotopic labeling strategy. Among the 2245 proteins predicted from the Cba. tepidum genome, approximately 970 proteins were detected in unlabeled samples, whereas approximately 630-640 proteins were detected in labeled samples comparing two different growth conditions. Wild-type cells growing on thiosulfate had an increased abundance of periplasmic cytochrome c-555 and proteins of the periplasmic thiosulfate-oxidizing SOX enzyme system when compared with cells growing on sulfide. A dsrM mutant of Cba. tepidum, which lacks the dissimilatory sulfite reductase DsrM protein and therefore is unable to oxidize sulfur globules to sulfite, was also investigated. When compared with wild type, the dsrM cells exhibited an increased abundance of DSR enzymes involved in the initial steps of sulfur globule oxidation (DsrABCL) and a decreased abundance of enzymes putatively involved in sulfite oxidation (Sat-AprAB-QmoABC). The results show that Cba. tepidum regulates the cellular levels of enzymes involved in sulfur metabolism and other electron-transferring processes in response to the availability of reduced sulfur compounds. PMID:22092713

Falkenby, Lasse G; Szymanska, Monika; Holkenbrink, Carina; Habicht, Kirsten S; Andersen, Jens S; Miller, Mette; Frigaard, Niels-Ulrik

2011-10-01

215

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

216

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

217

Evaluation of the technological feasibility, and cost of selected control alternatives necessary to meet the proposed Ohio SOâ regulations for industrial boilers and processes. Volume IV. E. I. Dupont de Nemours and Company, Cleveland sulfuric acid plant. Final report  

Microsoft Academic Search

This report presents an evaluation by the GCA Corporation, GCA\\/Technology Division, of technological feasibility and cost of complying with the proposed Ohio sulfur dioxide regulation (40 FR 52410, November 10, 1975) at the E. I. Dupont de Nemours and Company's Cleveland sulfuric acid plant. The final USEPA Sulfur Dioxide Control Strategy for the State of Ohio Technical Support Documents, Vol.

W. T. Stanley; R. R. Hall

1976-01-01

218

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

219

Are sulfur isotope ratios sufficient to determine the antiquity of sulfate reduction. [implications for chemical evolution  

NASA Technical Reports Server (NTRS)

Possible limitations on the use of sulfur isotope ratios in sedimentary sulfides to infer the evolution of microbial sulfate reduction are discussed. Current knowledge of the ways in which stable sulfur isotope ratios are altered by chemical and biological processes is examined, with attention given to the marine sulfur cycle involving various microbial populations, and sulfur reduction processes, and it is noted that satisfactory explanations of sulfur isotope ratios observed in live organisms and in sediments are not yet available. It is furthermore pointed out that all members of the same genus of sulfate reducing bacteria do not always fractionate sulfur to the same extent, that the extent of sulfur fractionation by many sulfate-reducing organisms has not yet been determined, and that inorganic processes can also affect sulfur isotope fractionation values. The information currently available is thus concluded to be insufficient to determine the time of initial appearance of biological sulfate reduction.

Ashendorf, D.

1980-01-01

220

Sulfur Volcanoes on Io?  

NASA Technical Reports Server (NTRS)

The unusual rheological properties of molten sulfur, in which viscosity decreases approximately four orders of magnitude as it cools from 170 to 120 C, may result in distinctive volcanic flow morphologies that allow sulfur flows and volcanoes to be identified on Io. Search of high resolution Voyager images reveals three features--Atar Patera, Daedalus Patera, and Kibero Patera--considered to be possible sulfur volcanoes based on their morphology. All three average 250 km in diameter and are distinguished by circular-to-oval central masses surrounded by irregular, widespread flows. Geometric relations indicate that the flows were emplaced after the central zone and appear to have emanated from their margins. The central zones are interpreted to be domes representing the high temperature stage of sulfur formed initially upon eruption. Rapid quenching formed a crust which preserved this phase of the emplacement. Upon cooling to 170 C, the sulfur reached a low viscosity runny stage and was released as the thin, widespread flows.

Greeley, R.; Fink, J.

1985-01-01

221

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

222

Inorganic Sulfur Compounds as Electron Donors in Purple Sulfur Bacteria  

Microsoft Academic Search

Most anoxygenic phototrophic bacteria can use inorganic sulfur compounds (e.g. sulfide, elemental sulfur, polysulfides, thiosulfate,\\u000a or sulfide) as electron donors for reductive carbon dioxide fixation during photolithoautotrophic growth. In these organisms,\\u000a light energy is used to transfer electrons from sulfur compounds to the level of the more highly reducing electron carriers\\u000a NAD(P)+ and ferredoxin. In this chapter the sulfur oxidizing

Christiane Dahl

223

Io's theothermal (sulfur) - Lithosphere cycle inferred from sulfur solubility modeling of Pele's magma supply  

NASA Astrophysics Data System (ADS)

Surface deposits of volatile compounds such as water (Earth) or sulfur (Io) on volcanically active bodies suggest that a magmatic distillation process works to concentrate volatiles in surface reservoirs. On Earth, this is the combined hydrologic and tectonic cycle. On Io, sulfurous compounds are transferred from the interior to the surface reservoirs through a combination of a mantle-sourced magmatic system, vertical cycling of the lithosphere, and a sulfur-dominated crustal thermal system that we here call the "theothermal" system. We present a geochemical analysis of this process using previously inferred temperature and oxygen fugacity constraints of Pele's basaltic magma to determine the behavior of sulfur in the ionian magmas. Sulfate to sulfide ratios of Pele's magma are -4.084 ± 0.6 and -6.442 ± 0.7 log10 units, comparable to or lower than those of mid-ocean ridge basalts. This reflects the similarity of Io's oxidation state with Earth's depleted mantle as previously suggested by Zolotov and Fegley (Zolotov, M.Y., Fegley, B. [2000]. Geophys. Res. Lett. 27, 2789-2792). Our calculated limits of sulfur solubility in melts from Pele's patera (˜1100-1140 ppm) are also comparable to terrestrial mid-ocean ridge basalts, reflecting a compositional similarity of mantle sources. We propose that the excess sulfur obvious on Io's surface comes from two sources: (1) an insoluble sulfide liquid phase in the magma and (2) theothermal near-surface recycling.

Battaglia, Steven M.; Stewart, Michael A.; Kieffer, Susan W.

2014-06-01

224

Oxidative metabolism of inorganic sulfur compounds by bacteria.  

PubMed

The history of the elucidation of the microbiology and biochemistry of the oxidation of inorganic sulfur compounds in chemolithotrophic bacteria is briefly reviewed, and the contribution of Martinus Beijerinck to the study of sulfur-oxidizing bacteria highlighted. Recent developments in the biochemistry, enzymology and molecular biology of sulfur oxidation in obligately and facultatively lithotrophic bacteria are summarized, and the existence of at least two major pathways of thiosulfate (sulfur and sulfide) oxidation confirmed. These are identified as the 'Paracoccus sulfur oxidation' (or PSO) pathway and the 'S4intermediate' (or S4I) pathway respectively. The former occurs in organisms such as Paracoccus (Thiobacillus) versutus and P. denitrificans, and possibly in Thiobacillus novellus and Xanthobacter spp. The latter pathway is characteristic of the obligate chemolithotrophs (e.g. Thiobacillus tepidarius, T. neapolitanus, T. ferrooxidans, T. thiooxidans) and facultative species such as T. acidophilus and T. aquaesulis, all of which can produce or oxidize tetrathionate when grown on thiosulfate. The central problem, as yet incompletely resolved in all cases, is the enzymology of the conversion of sulfane-sulfur (as in the outer [S-] atom of thiosulfate [-S-SO3-]), or sulfur itself, to sulfate, and whether sulfite is involved as a free intermediate in this process in all, or only some, cases. The study of inorganic sulfur compound oxidation for energetic purposes in bacteria (i.e. chemolithotrophy and sulfur photolithotrophy) poses challenges for comparative biochemistry. It also provides evidence of convergent evolution among diverse bacterial groups to achieve the end of energy-yielding sulfur compound oxidation (to drive autotrophic growth on carbon dioxide) but using a variety of enzymological systems, which share some common features. Some new data are presented on the oxidation of 35S-thiosulfate, and on the effect of other anions (selenate, molybdate, tungstate, chromate, vanadate) on sulfur compound oxidation, including observations which relate to the roles of polythionates and elemental sulfur as intermediates. PMID:9049021

Kelly, D P; Shergill, J K; Lu, W P; Wood, A P

1997-02-01

225

ORIGINAL ARTICLE Sulfur oxidizers dominate carbon fixation  

E-print Network

ORIGINAL ARTICLE Sulfur oxidizers dominate carbon fixation at a biogeochemical hot spot in the dark clade of marine gamma-proteobacterial sulfur oxidizers (GSOs) are distributed throughout proteins for sulfur oxidation (adenosine phosphosulfate reductase, sox (sulfur oxidizing system

Hansell, Dennis

226

Genetic engineering of sulfur-degrading Sulfolobus. Final technical report, September 1, 1990--August 31, 1991  

SciTech Connect

The objectives of the proposed research is to first establish a plasmid-mediated genetic transformation system for the sulfur degrading Sulfolobus, and then to clone and overexpress the genes encoding the organic-sulfur-degrading enzymes from Sulfolobus- as well as from other microorganisms, to develop a Sulfolobus-based microbial process for the removal of both organic and inorganic sulfur from coal.

Ho, N.W.Y.

1991-12-31

227

Ssq1, a Mitochondrial Hsp70 Involved in Iron-Sulfur (Fe/S) Center Biogenesis  

E-print Network

Ssq1, a Mitochondrial Hsp70 Involved in Iron-Sulfur (Fe/S) Center Biogenesis SIMILARITIES function together to assist in the biogenesis of iron- sulfur (Fe/S) centers in the mitochondrial matrix chaperones work to- gether, along with other proteins, in the processes of iron- sulfur center biogenesis

Craig, Elizabeth A

228

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

229

Meteoritic Sulfur Isotopic Analysis  

NASA Astrophysics Data System (ADS)

Funds were requested to continue our program in meteoritic sulfur isotopic analysis. We have recently detected a potential nucleosynthetic sulfur isotopic anomaly. We will search for potential carriers. The documentation of bulk systematics and the possible relation to nebular chemistry and oxygen isotopes will be explored. Analytical techniques for delta33, delta34S, delta36S isotopic analysis were improved. Analysis ofmilligram samples is now possible. A possible relation between sulfur isotopes and oxygen was detected, with similar group systematics noted, particularly in the case of aubrites, ureilites and entstatite chondrites. A possible nucleosynthetic excess S-33 has been noted in bulk ureilites and an oldhamite separate from Norton County. High energy proton (approximately 1 GeV) bombardments of iron foils were done to experimentally determine S-33, S-36 spallogenic yields for quantitation of isotopic measurements in iron meteorites. Techniques for measurement of mineral separates were perfected and an analysis program initiated. The systematic behavior of bulk sulfur isotopes will continue to be explored.

Thiemens, Mark H.

1996-01-01

230

Meteoritic Sulfur Isotopic Analysis  

NASA Technical Reports Server (NTRS)

Funds were requested to continue our program in meteoritic sulfur isotopic analysis. We have recently detected a potential nucleosynthetic sulfur isotopic anomaly. We will search for potential carriers. The documentation of bulk systematics and the possible relation to nebular chemistry and oxygen isotopes will be explored. Analytical techniques for delta(sup 33), delta(sup 34)S, delta(sup 36)S isotopic analysis were improved. Analysis of sub milligram samples is now possible. A possible relation between sulfur isotopes and oxygen was detected, with similar group systematics noted, particularly in the case of aubrites, ureilites and entstatite chondrites. A possible nucleosynthetic excess S-33 has been noted in bulk ureilites and an oldhamite separate from Norton County. High energy proton (approximately 1 GeV) bombardments of iron foils were done to experimentally determine S-33, S-36 spallogenic yields for quantitation of isotopic measurements in iron meteorites. Techniques for measurement of mineral separates were perfected and an analysis program initiated. The systematic behavior of bulk sulfur isotopes will continue to be explored.

Thiemens, Mark H.

1996-01-01

231

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...

232

Sulfur Dioxide Pollution Monitor.  

ERIC Educational Resources Information Center

The sulfur dioxide pollution monitor described in this document is a government-owed invention that is available for licensing. The background of the invention is outlined, and drawings of the monitor together with a detailed description of its function are provided. A sample stream of air, smokestack gas or the like is flowed through a…

National Bureau of Standards (DOC), Washington, DC.

233

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

PubMed

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. PMID:23695634

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, Arpád; Theato, Patrick; Mackay, Michael E; Sung, Yung-Eun; Char, Kookheon; Pyun, Jeffrey

2013-06-01

234

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

235

Development of instrumental methods of analysis of sulfur compounds in coal process streams. Twelfth quarterly technical progress report, July-September 1980  

SciTech Connect

In the extension and refinement of thermodynamic survey and construction of pourbaix diagrams, when warranted by slow kinetics, specified moieties can appropriately be eliminated from consideration while assuming attainment of equilibrium between all other species. In the voltammetric methods development, it was found thaat tetrathionate can be quantitated by differential pulse polarography at the dropping mercury electrode. In the enthalpimetric methods development, sulfide can be determined by titration with standard thallous nitrate to a thermometric endpoint. The Tl/sub 2/S precipitated does not interfere in the subsequent acidimetric titration of Bronsted-base moieties, such as sulfite, carbonate and hydroxide. Generally, liquefaction by-product water samples are characterized by more negative redox potentials than their gasification counterparts. This reflects a preponderance of sulfidic sulfur versus thiosulfate. In gasification by-product waters, the situation is reversed. Cartesian displays of pH-redox potential correlations were constructed, revealing distinct patterns which clearly illustrate the difference between liquefaction and gasification by-product water samples.

Jordan, J.

1980-10-01

236

Atmospheric sulfur in Archean komatiite-hosted nickel deposits.  

PubMed

Some of Earth's largest iron-nickel (Fe-Ni) sulfide ore deposits formed during the Archean and early Proterozoic. Establishing the origin of the metals and sulfur in these deposits is critical for understanding their genesis. Here, we present multiple sulfur isotope data implying that the sulfur in Archean komatiite-hosted Fe-Ni sulfide deposits was previously processed through the atmosphere and then accumulated on the ocean floor. High-temperature, mantle-derived komatiite magmas were then able to incorporate the sulfur from seafloor hydrothermal sulfide accumulations and sulfidic shales to form Neoarchean komatiite-hosted Fe-Ni sulfide deposits at a time when the oceans were sulfur-poor. PMID:19965423

Bekker, Andrey; Barley, Mark E; Fiorentini, Marco L; Rouxel, Olivier J; Rumble, Douglas; Beresford, Stephen W

2009-11-20

237

The evolution of infalling sulfur species in Titan's atmosphere  

NASA Astrophysics Data System (ADS)

Aims: We studied the hypothesis that micrometeorites and Enceladus' plume activity could carry sulfur-bearing species into the upper atmosphere of Titan, in a manner similar to oxygen-bearing species. Methods: We have developed a detailed photochemical model of sulfur compounds in the atmosphere of Titan that couples hydrocarbon, nitrogen, oxygen, and sulfur chemistries. Results: Photochemical processes produce mainly CS and H2CS in the upper atmosphere of Titan and C3S, H2S and CH3SH in the lower atmosphere. Mole fractions of these compounds depend significantly on the source of sulfur species. Conclusions: A possible future detection of CS (or the determination of a low upper limit) could be used to distinguish the two scenarios for the origin of sulfur species, which then could help to differentiate the various scenarios for the origin of H2O, CO, and CO2 in the stratosphere of Titan.

Hickson, K. M.; Loison, J. C.; Cavalié, T.; Hébrard, E.; Dobrijevic, M.

2014-12-01

238

Chemical Composition of Microimpurities in Jet Fuels from Sulfurous Petroleum.  

National Technical Information Service (NTIS)

The microimpurities of the jet fuels from sulfurous petroleums consist of ash elements, tars, and 'structural' water. In the process of transportation, settling, and filtration of the fuels there occurs a separation of the microimpurities in accordance wi...

V. N. Zrelov, N. I. Marinchenko

1964-01-01

239

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

240

Sulfur dichloride, SCl2  

NSDL National Science Digital Library

This month's molecule is sulfur dichloride, SCl2. This and other small inorganic molecules are discussed in the article by Matta and Gillespie. They describe electron density in molecules and how to analyze it to obtain information about molecular bonding and structure. Different depictions of electron density in SCl2 and other small molecules emphasize different aspects of their electron density and of the structures of the molecules.

241

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

242

The 1950 sulfur flow of Mauna Loa: Considerations for Io  

NASA Technical Reports Server (NTRS)

Some of the geological relationships observed in the Mauna Loa sulfur flow may apply in considering volcanic processes on Io. Given the presence of sulfur/sulfur compounds in the eruption plumes and on the surface of Io, it is likely that extensive secondary deposits of sulfur exist, some of which may be of fumarolic origin and analogous to the Mauna Loa deposit. Given the likelihood of silicate volcanism of Io based on the inferred material properties of some flows, and the attendant high temperatures for silicate volcanism, it is likely that the secondary surface deposits of sulfur would have been mobilized without being heated to the high viscosity stage. Mobilized sulfur flows on Io may flow long distances as a result of: (1) low viscosities in the melting range; (2) sustained effusion resulting from continued heating source area; (3) continued remobilization within the flow as a consequence of surges from the source; and (4) extension via lava tubes, or similar conduits through which there is little heat loss. Sulfur flows may form a relatively thin veneer over silicate flows and other surface units, given their fluidity and low mobilization temperature. Active splashing and splattering may spread sulfur over a wider area contributing the bright blooms observed in association with some Ionian flows.

Greeley, R.; Theilig, E.; Christensen, P.

1984-01-01

243

Ultrasonic coal-wash for de-sulfurization.  

PubMed

Coal is the one of the world's most abundant fossil fuel resources. It is not a clean fuel, as it contains ash and sulfur. SOx as a pollutant are a real threat to both the ecosystem and to human health. There are numerous de-sulfurization methods to control SO(2) emissions. Nowadays, online flue gas de-sulfurization is being used as one such method to remove sulfur from coal during combustion. The biggest disadvantage associated with this method is formation of by-products (FGD gypsum). A way for effective usage of FGD gypsum has not yet been found. This will lead to acute and chronic effects to humans as well as plants. Power ultrasound can be used for the beneficiation of coal by the removal of sulfur from coal prior to coal combustion. The main effects of ultrasound in liquid medium are acoustic cavitation and acoustic streaming. The process of formation, growth and implosion of bubbles is called cavitation. Bulk fluid motion due to sound energy absorption is known as acoustic streaming. In addition, coupling of an acoustic field to water produces OH radicals, H(2)O(2), O(2), ozone and HO(2) that are strong oxidizing agents. Oxidation that occurs due to ultrasound is called Advanced Oxidation Process (AOP). It converts sulfur from coal to water-soluble sulphates. Conventional chemical-based soaking and stirring methods are compared here to ultrasonic methods of de-sulfurization. The main advantages of ultrasonic de-sulfurization over conventional methods, the mechanism involved in ultrasonic de-sulfurization and the difference between aqueous-based and solvent-based (2N HNO(3), 3-volume percentage H(2)O(2)) de-sulfurization are investigated experimentally. PMID:21115263

Ambedkar, B; Nagarajan, R; Jayanti, S

2011-05-01

244

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

245

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

246

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

247

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

248

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

249

Mössbauer study of the inorganic sulfur removal from coals  

NASA Astrophysics Data System (ADS)

Mössbauer Spectroscopy (MS) was applied to study the occurrence and behavior of the iron-sulfur-containing minerals in coal and coal fractions obtained by different separation methods: hydrocyclonic, flotation and chemical removal process. Samples of one high sulfur coal from Guachinte mine (Valle, Colombia) and three low sulfur coals from the El Salitre zone (Paipa-Boyacá, Colombia) were analyzed. MS evidenced only the presence of pyrite in Esmeralda and Las Casitas coals, while it identified pyrite and siderite on Cerezo coal. MS and SEM- EDX confirm the inorganic sulfur removal on Guachinte coal submitted to hydrocyclonic removal process. MS of the precipitated coal fraction from Las Casitas mine obtained by flotation in water showed the presence of ferrous sulfate because of coal-weathering process. Treatment with hot diluted HNO3 equal to 27 acid on raw coal sample from Las Casitas mine showed that almost all of the pyrite in raw coal was removed.

Reyes Caballero, F.; Martínez Ovalle, S. A.

2014-01-01

250

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

251

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

Code of Federal Regulations, 2013 CFR

...National primary ambient air quality standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection...National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...

2013-07-01

252

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

Code of Federal Regulations, 2012 CFR

...National primary ambient air quality standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection...National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...

2012-07-01

253

Fate of excess sulfur in higher plants  

Microsoft Academic Search

The mechanisms which have evolved in higher plants to cope with excess sulfur in their environments are reviewed. Survival in a sulfur-rich environment is seldom achieved through avoidance of the intake of sulfur. The presence of excess sulfur in the soil or in the air usually results in an intake of excess sulfur into plants. An immediate injury by the

H Rennenberg

1984-01-01

254

Exploring the Arabidopsis sulfur metabolome.  

PubMed

Sulfur plays a crucial role in protein structure and function, redox status and plant biotic stress responses. However, our understanding of sulfur metabolism is limited to identified pathways. In this study, we used a high-resolution Fourier transform mass spectrometric approach in combination with stable isotope labeling to describe the sulfur metabolome of Arabidopsis thaliana. Databases contain roughly 300 sulfur compounds assigned to Arabidopsis. In comparative analyses, we showed that the overlap of the expected sulfur metabolome and the mass spectrometric data was surprisingly low, and we were able to assign only 37 of the 300 predicted compounds. By contrast, we identified approximately 140 sulfur metabolites that have not been assigned to the databases to date. We used our method to characterize the ?-glutamyl transferase mutant ggt4-1, which is involved in the vacuolar breakdown of glutathione conjugates in detoxification reactions. Although xenobiotic substrates are well known, only a few endogenous substrates have been described. Among the specifically altered sulfur-containing masses in the ggt4-1 mutant, we characterized one endogenous glutathione conjugate and a number of further candidates for endogenous substrates. The small percentage of predicted compounds and the high proportion of unassigned sulfur compounds identified in this study emphasize the need to re-evaluate our understanding of the sulfur metabolome. PMID:24147819

Gläser, Katharina; Kanawati, Basem; Kubo, Tobias; Schmitt-Kopplin, Philippe; Grill, Erwin

2014-01-01

255

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

256

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

Microsoft Academic Search

The first step in processing low-enriched uranium (LEU) targets for production of ⁹⁹Mo 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

B. Srinivasan; R. A. Leonard; S. Aase

1995-01-01

257

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

258

Desulfurization of Gaseous Fuels with Recovery of Elemental Sulfur: An Overview  

Microsoft Academic Search

Emphasis on environmental concerns due to emission of sulfur species through utilization of gaseous fuels containing high sulfur constituents has led to the development of a number of physicochemical and biological processes for desulfurization of gaseous fuels. This article summarizes information on the development of liquid and gaseous redox processes and biological processes for desulfurization of gaseous fuels with concomitant

R. A. Pandey; S. Malhotra

1999-01-01

259

Sulfur and primary production in aquatic environments: an ecological perspective  

Microsoft Academic Search

Sulfur is one of the critical elements in living matter, as it participates in several structural, metabolic and catalytic\\u000a activities. Photosynthesis is an important process that entails the use of sulfur during both the light and carbon reactions.\\u000a Nearly half of global photosynthetic carbon fixation is carried out by phytoplankton in the aquatic environment. Aquatic environments\\u000a are very different from

Alessandra Norici; Ruediger Hell; Mario Giordano

2005-01-01

260

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

261

Volume efficient sodium sulfur battery  

DOEpatents

In accordance with the teachings of this specification, a sodium sulfur battery is formed as follows. A plurality of box shaped sulfur electrodes are provided, the outer surfaces of which are defined by an electrolyte material. Each of the electrodes have length and width dimensions substantially greater than the thicknesses thereof as well as upwardly facing surface and a downwardly facing surface. An electrode structure is contained in each of the sulfur electrodes. A holding structure is provided for holding the plurality of sulfur electrodes in a stacked condition with the upwardly facing surface of one sulfur electrode in facing relationship to the downwardly facing surface of another sulfur electrode thereabove. A small thickness dimension separates each of the stacked electrodes thereby defining between each pair of sulfur electrodes a volume which receives the sodium reactant. A reservoir is provided for containing sodium. A manifold structure interconnects the volumes between the sulfur electrodes and the reservoir. A metering structure controls the flow of sodium between the reservoir and the manifold structure.

Mikkor, Mati (Ann Arbor, MI)

1980-01-01

262

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

263

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

264

Bacterial Sulfur Globules: Occurrence, Structure and Metabolism  

Microsoft Academic Search

Reduced sulfur compounds such as sulfide, polysulfides, thiosulfate, polythionates, and elemental sulfur are oxidized by a\\u000a large and diverse group of prokaryotes, including the phototrophic sulfur bacteria, the thiobacilli and other colorless sulfur\\u000a bacteria and some thermophilic Archaea. Typically, these sulfur compounds are oxidized to sulfate but in many cases globules of polymeric, water-insoluble sulfur\\u000a accumulate as a transient and

Christiane Dahl; Alexander Prange

265

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

266

Determination of sulfur-containing compounds in diesel oils by comprehensive two-dimensional gas chromatography with a sulfur chemiluminescence detector.  

PubMed

This article reports an analytical method for separating, identifying and quantitating sulfur-containing compounds and their groups in diesel oils (170-400 degrees C) using comprehensive two-dimensional gas chromatography coupled with a sulfur chemiluminescence detector. The identification of target compounds and their groups was based on standard substances, the group separation feature and tile-effect of comprehensive two-dimensional gas chromatography. The quantitative analysis on major sulfur compounds and total sulfur was carried out based on the linear response of sulfur chemiluminescence detector and the internal standards method. The results of total sulfur determination in the samples were compared with those from ASTM D 4294 standard method, the R.S.D. percentage were <6.02%, correctness of this method can meet the industrial requirement. To the end, the method developed was used to investigate the sulfur-containing compounds in different diesel oils, the result shows that the distribution of sulfur-containing compounds in diesel oils from different process units are apparently different. The sulfur compounds in fluid catalytic cracking (FCC), residuum fluid catalytic cracking (RFCC) diesel oils mainly exist in the form of alkyl-substituted dibenzothiophenes that add up to about 40-50% of the total sulfur, while this number is only 6-8 and 20-28% in visbreaking (VB) and delayed-coking (DC) diesel oils, respectively. PMID:14650608

Hua, Ruixiang; Li, Yanyan; Liu, Wei; Zheng, Jincheng; Wei, Haibo; Wang, Jinghua; Lu, Xin; Kong, Hongwei; Xu, Guowang

2003-11-26

267

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

268

Method for manufacture of ammonium thiosulfate from ammonia and solid sulfur or H/sub 2/S rich gas stream and/or both solid sulfur and H/sub 2/S gas streams  

SciTech Connect

A process for the manufacture of aqueous ammonium thiosulfate from sulfur dioxide wherein ammonium sulfite is formed as an intermediate product by the scrubbing reaction of ammonia with sulfur dioxide in the presence of water. Preferably, the ammonia is added to the sulfur dioxide in the bottom of the second scrubbing reaction vessel so as to maintain the sulfur dioxide and ammonia in liquid phase.

Ott, C.J.

1984-10-23

269

Dislocation reduction in sulfur- and germanium-doped indium phosphide single crystals grown by the vertical gradient freeze process: A transient finite-element study  

NASA Astrophysics Data System (ADS)

During the growth of indium phosphide (InP) crystals, dislocations are mostly generated in a plastically deformed crystal due to crystallographic glide caused by excessive thermal stresses. High dislocation density presented in the InP crystal can reduce the performance, lifetime, and reliability of the InP-based microelectronic and optoelectronic devices/circuits. The generation of dislocations in InP single crystals grown from the melt can be predicted by using a transient finite-element model. This model couples microscopic dislocation motion and multiplication to macroscopic plastic deformation during the crystal growth process. The temperature fields in the crystal are determined by solving the partial differential equations of heat transfer for the vertical gradient freeze (VGF) process. These temperature fields are then employed to the transient finite-element model to study the effects of doping impurities and growth parameters (i.e., imposed temperature gradient, crystal radius, and growth rate) on dislocation reduction in InP crystals grown by different VGF processes.

Zhu, X. A.; Tsai, C. T.

2005-02-01

270

11704 J. Am. Chem. SOC.1995,117, 11704-11709 Regiochemical Selectivity in the Carbon-Sulfur Bond Cleavage  

E-print Network

11704 J. Am. Chem. SOC.1995,117, 11704- 11709 Regiochemical Selectivity in the Carbon- Sulfur Bond be an importantstep in the removal of sulfur from thiophene in the hydrodesulfur- ization (HDS) process.' Thiophene and its benzo derivatives represent abundant sulfur-containing impurities in coal and petroleum feedstocks

Jones, William D.

271

Intermediate Length Rieske Iron-Sulfur Protein Is Present and Functionally Active in the Cytochrome bc1 Complex of  

E-print Network

Intermediate Length Rieske Iron-Sulfur Protein Is Present and Functionally Active in the Cytochrome-transla- tional processing of the Rieske iron-sulfur protein of Saccharomyces cerevisiae and its assembly been changed by site-directed mutagenesis of the cloned iron- sulfur protein gene, so

Trumpower, Bernard L.

272

Production of elemental sulfur and methane from H{sub 2}S and CO{sub 2} derived from a coal desulfurization process. Quarterly technical progress report, January 1, 1995--March 31, 1995  

SciTech Connect

During the sixth quarter of the project, simulations were carried out to investigate the feasibility of producing elemental sulfur and methane from hydrogen sulfide and carbon dioxide by using the overall reaction of H{sub 2}S and CO{sub 2} based on the following equation: 4 H{sub 2}S + CO{sub 2} {l_equilibrium} 2 S{sub 2} + CH{sub 4}+2 H{sub 2}O. The results indicate that two reaction zones are required to realize the above reaction. The first reaction zone should be composed of multiple stages to recover the elemental sulfur without the equilibrium limitations. With optimum temperatures in each zone, the conversion can be increased significantly. The simulation also indicates less amounts of by-products, such as COS, CS{sub 2} and SO{sub 2}. The limitation on the extraction of sulfur is directly related to the sulfur vapor pressure.

Jiang, X.; Khang, S.J.

1995-08-01

273

Development of a zero-emissions sulfur-recovery process: 1. Thermochemistry and reaction kinetics of mixtures of H[sub 2]S and CO[sub 2] at high temperature  

Microsoft Academic Search

When hydrogen sulfide is heated above 600 C in the presence of carbon dioxide, the conversion of H[sub 2]S to elemental sulfur is greater than when hydrogen sulfide is heated alone. Formation of elemental sulfur is favored by high temperature, low pressure, and low water content in the gas. The rate-limiting step is the thermal dissociation of H[sub 2]S. The

G. P. Towler; S. Lynn

1993-01-01

274

Discovery of practical production processes for arylsulfur pentafluorides and their higher homologues, bis- and tris(sulfur pentafluorides): Beginning of a new era of "super-trifluoromethyl" arene chemistry and its industry  

PubMed Central

Summary Various arylsulfur pentafluorides, ArSF5, have long been desired in both academic and industrial areas, and ArSF5 compounds have attracted considerable interest in many areas such as medicines, agrochemicals, and other new materials, since the highly stable SF5 group is considered a “super-trifluoromethyl group” due to its significantly higher electronegativity and lipophilicity. This article describes the first practical method for the production of various arylsulfur pentafluorides and their higher homologues, bis- and tris(sulfur pentafluorides), from the corresponding diaryl disulfides or aryl thiols. The method consists of two steps: (Step 1) treatment of a diaryl disulfide or an aryl thiol with chlorine in the presence of an alkali metal fluoride, and (step 2) treatment of the resulting arylsulfur chlorotetrafluoride with a fluoride source, such as ZnF2, HF, and Sb(III/V) fluorides. The intermediate arylsulfur chlorotetrafluorides were isolated by distillation or recrystallization and characterized. The aspects of these new reactions are revealed and reaction mechanisms are discussed. As the method offers considerable improvement over previous methods in cost, yield, practicality, applicability, and large-scale production, the new processes described here can be employed as the first practical methods for the economical production of various arylsulfur pentafluorides and their higher homologues, which could then open up a new era of “super-trifluoromethyl” arene chemistry and its applications in many areas. PMID:22509218

Garrick, Lloyd M; Saito, Norimichi

2012-01-01

275

Sulfur-free cleaning strategy for advanced mask manufacturing  

NASA Astrophysics Data System (ADS)

Existing cleaning technology using sulfuric acid based chemistry has served the mask industry quite well over the years. However, the existence of residue on mask surfaces is becoming more and more of a problem at the high energy wavelengths used in lithography tool for wafer manufacturing. This is evident by the emergence of sub-pellicle defect growth and backside hazing issues. A large source of residual contamination on the surface of masks is from the mask manufacturing process, particularly the cleaning portion involving sulfuric acid. Cleaning strategies can be developed that eliminate the use of sulfuric acid in the cleaning process for advanced photomasks and alternative processes can be used for cleaning masks at various stages of the manufacturing process. Implementation of these new technologies into manufacturing will be discussed as will the resulting improvements, advantages, and disadvantages over pre-existing mask cleaning processes.

Kindt, Louis; Watts, Andrew; Burnham, Jay; Aaskov, William

2006-10-01

276

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

277

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

278

Isotopic composition and concentration of sulfur in carbonaceous chondrites  

NASA Technical Reports Server (NTRS)

New sulfur isotopic ratio measurements are reported for seven carbonaceous chondrites. Newly developed procedures permit measurement of delta S-33, delta S-34, and delta S-36 at precisions significantly greater than previously reported. A search for S-36 nucleosynthetic anomalies coproduced with anomalies in, for example, Ti-50 and Ca-48 was negative. The high endemic sulfur concentration probably dilutes any S-36 anomaly, and separation of individual sulfur phases may be needed to identify S-36 carrier phases. Large internal isotopic variations are observed, deriving from parent body and possibly nebular processes. Chondrule separates from Allende demonstrate isotopic compositions which vary as a function of diameter. High-temperature gas-solid exchange and a two-component mixing model may account for the observations. High-resolution isotopic data and structural information are reported for organic sulfur compounds separated by chemical extractions. The insoluble organics appear to be of either aliphatic or alicyclic structure and are dominant phases.

Gao, Xia; Thiemens, Mark H.

1993-01-01

279

Elemental sulfur recovery from desulfurization sorbents in advanced power systems  

SciTech Connect

Regenerable metal oxide sorbents, such as zinc titanate, are being developed to efficiently remove hydrogen sulfide (H{sub 2}S) from coal gas in advanced power systems. Dilute air regeneration of the sorbents produces a tailgas containing a few percent sulfur dioxide (SO{sub 2}). Catalytic reduction of the SO{sub 2} to elemental sulfur with a coal gas slipstream using the Direct Sulfur Recovery Process (DSRP) is a leading first-generation technology. Currently the DSRP is undergoing field testing at gasifier sites. The objective of this study is to develop second-generation processes that produce elemental sulfur with limited use of coal gas. Novel approaches that were evaluated to produce elemental sulfur from sulfided sorbents include (1) SO{sub 2} regeneration, (2) substoichiometric oxidation, (3) steam regeneration followed by H{sub 2}S oxidation, and (4) steam-air regeneration. Experimental results at high temperature and high pressure demonstrate that, with simple sorbent modifications, direct regeneration to elemental sulfur is feasible without the use of coal gas.

Dorchak, T.P. [Morgantown Energy Technology Center, WV (United States); Gangwal, S.K.; Turk, B.S. [Research Triangle Institute, Research Triangle Park, NC (United States)

1995-12-31

280

Sulfur in the Apollo 17 basalts and their source regions  

NASA Technical Reports Server (NTRS)

Thirty-two Apollo 17 mare basalts have been analyzed for their total sulfur and metallic iron abundances. Sulfur abundances range from 1580 to 2770 microgram S/g with a median value of 1860 microgram S/g. Metallic iron abundances ranged from 0.033 to 0.21 wt.% Fe, with a mean value of 0.13 wt% Fe. The coarse-grained basalts contain more metallic iron than the fine-grained basalts. The metallic iron and sulfur abundances are not apparently related to the cooling rates of the basalts. A slight negative correlation exists between the concentrations of metallic iron and total sulfur for the Apollo 17 basalts. Sulfur content of the mare basalts increases with increasing degrees of fractionation whereas the metallic iron content decreases. Metallic iron in mare basalts may be ascribed to a variety of processes; at present the dominant process is unknown. The source regions for the Apollo 17 and 11 basalts were saturated with sulfur as compared to the Apollo 12 and 15 low titanium basalts which were not saturated.

Gibson, E. K., Jr.; Morris, R. V.; Usselman, T. M.

1976-01-01

281

In-situ Raman Spectroscopic Investigation of Sulfur, Sulfur-Water, and Sulfur-Methane-Water Systems Between 22 and 450 °C  

NASA Astrophysics Data System (ADS)

Previous investigations have used native sulfur as a catalyst for thermochemical sulfate reduction (TSR) experiments, but the mechanisms for the TSR processes are still not clear. In order to establish possible mechanisms, we investigated the sulfur, sulfur-water, and sulfur-water-methane systems in the fused silica capillary capsules (FSCC) by using the USGS-type heating-cooling stage and in-situ Raman spectroscopy between 22 and 450 °C. Samples were loaded in the FSCC (0.3 mm OD, 0.1 mm ID, and 10 to 25 mm long) using the method of Chou et al. (2008, Geochim. Cosmochim. Acta, 72, 5217). Raman spectra were collected with a JY/Horiba LabRam HR Raman system using 532.06 nm laser excitation. In the sulfur system, we observed (1) the melting of native sulfur at 115.5 °C; (2) the breaking of S8 rings during heating as indicated by the gradual reduction in intensity of Raman signals near 219 and 473 cm-1; (3) the formation of new sulfur-bearing species indicated by the presence of Raman bands near 1440, 1250 cm-1, and other signals between 200 and 550 cm-1; and (4) the reappearance of S8 bands and the reduction of the signals near 1440 and 1250 cm-1 at room temperature (RT). In the sulfur-water system, we observed (1) the Raman bands near 1440 and 1250 cm-1 in the aqueous, vapor, and liquid sulfur phases during heating; (2) the presence of H2S (~2592 cm-1) and HS- (~2575 cm-1) in the aqueous phase above about 260 °C; (3) the disproportionation reaction of S to H2S and SO2/bisulfate, which occurred after L-V homogenization at about 369 °C, and was indicated by the presence of HSO4- (~1045 cm-1) and SO2 (~1149 cm-1); (4) the presence of intermediate species indicated by the Raman signals between 200 and 720 cm-1 during heating; (5) the reduction of Raman band intensities of SO2 and H2S during cooling and the disappearance of SO2 below 310 °C; and (6) the detection of SO42- (~980 cm-1) and H2S (~2590 cm-1) in the aqueous phase and H2S (~2611 cm-1) in vapor phase one day after cooling to RT. Our results indicate the reversibility of the disproportionation reaction. In the sulfur-water-methane system, we observed (1) the Raman bands of sulfur-bearing species near 1440 and 1250 cm-1 in the aqueous, vapor, and liquid sulfur phases during heating; (2) the generation of H2S and CO2 in both aqueous and vapor phases, and the increase of the intensities of their Raman signals with increasing temperature; and (3) the presence of solid sulfur together with CO2 and H2S in both aqueous and vapor phases after cooling to RT. However, we did not observe the formation of any high-valence sulfur species (e.g., SO2, HSO4-, and SO42-) in this system, indicating the disproportionation reaction of sulfur did not occur in the presence of methane. Our in-situ observation method has the potential of providing important information for the TSR processes, which is difficult to obtain from the conventional quenching method.

Yuan, S.; Chou, I.; Li, J.; Burruss, R. C.

2009-12-01

282

Sulfur abundances and distributions in mare basalts and their source magmas  

NASA Technical Reports Server (NTRS)

An inverse correlation between metallic iron content and total sulfur abundances was observed by Gibson and Moore (1974) for five Apollo 17 and six Apollo 15 basalts. An investigation was conducted with the objective to distinguish between two processes leading to the inverse metallic iron and total sulfur correlation. The investigation included analyses of ten Apollo 15 and five Apollo 17 basalts for their sulfur and metallic iron abundances along with carbon and hydrogen. The sulfur isotopic compositions were measured for a possible identification of the fractionation processes which might have occurred during volatilization of the basalts.

Gibson, E. K., Jr.; Chang, S.; Lennon, K.; Moore, G. W.; Pearce, G. W.

1975-01-01

283

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...

284

A global three-dimensional model of the tropospheric sulfur cycle  

Microsoft Academic Search

The tropospheric part of the atmospheric sulfur cycle has been simulated in a global three-dimensional model. The model treats the emission, transport, chemistry, and removal processes for three sulfur components; DMS (dimethyl sulfide), SO2 and SO42- (sulfate). These processes are resolved using an Eulerian transport model, the MOGUNTIA model, with a horizontal resolution of 10° longitude by 10° latitude and

J. Langner; H. Rodhe

1991-01-01

285

Colourless sulfur bacteria and their role in the sulfur cycle  

Microsoft Academic Search

Summary  The bacteria belonging to the families of the Thiobacteriaceae, Beggiatoaceae and Achromatiaceae are commonly called the colourless\\u000a sulfur bacteria. While their ability to oxidize reduced inorganic sulfur compounds has clearly been established, it is still\\u000a not known whether all these organisms can derive metabolically useful energy from these oxidations.\\u000a \\u000a During the last decades research has mainly focussed on the genus

J. Gijs Kuenen

1975-01-01

286

Numerical Study of Sulfur Outgassing in Response to Decompression and Crystallization  

NASA Astrophysics Data System (ADS)

Volcanic sulfur emissions impact climate over regional and sometimes global scales. In most explosive eruptions, sulfur emissions are greatly in excess of estimates based on sulfur content in melt at magma chamber pressure; it is commonly referred to as excess sulfur degassing. One of the possible explanations for this phenomenon is that sulfur is stored in an exsolved gas phase in the upper crustal reservoir. In order to test this hypothesis, we implemented a model for the growth of volatile bubbles from a silicate melt based on the work of Lensky et al. (2004) and Forestier-Coste et al. (2012). Our model includes the diffusion and partitioning of sulfur from the melt to bubbles. Basically, there are two processes for bubbles to grow, and retain sulfur, from the melt: (1) degassing during magmas ascent in conduits (first boiling) and (2) bubble nucleation and growth as magma cools and crystallizes (second boiling). We present calculations of diffusion under different decompression rates to simulate first boiling. Our results suggest that the sulfur uptake by bubbles during decompression driven degassing in volcanic conduits is typically not efficient. For most decompression rates, a much smaller amount of sulfur than predicted from equilibrium partitioning is found in bubbles. Thus, a balanced sulfur budget requires sulfur enrichment in bubbles prior to eruption. To test the efficiency of sulfur uptake by bubbles during the thermal maturation of magmas in shallow reservoirs, we have also developed a model for bubble growth and sulfur uptake during second boiling. Results show that efficient sulfur extraction into the magmatic volatile phase requires a crystallization-driven exsolution stage.

Bachmann, O.; Su, Y.; Huber, C.; Zajacz, Z.

2013-12-01

287

Development of instrumental methods of analysis of sulfur compounds in coal process streams. Quarterly technical progress report, April-June 1981  

SciTech Connect

This report covers the seventh quarter of a two-year contract renewal period. Task 1: extension and refinement of thermodynamic survey and construction of pourbaix diagrams. Work has been completed on schedule and has previously been reported in FE-10482-14 (1981). Task 2: voltammetric methods development. The hydrososulfide moiety HS/sup -/ is not electroreducible at the dropping mercury electrode. A mixture of HS/sup -/ and of the polysulfide anions S/sub 5//sup -2/, S/sub 4//sup -2/, S/sub 3//sup -2/ yielded a complex polarogram which included a narrow limiting current domain. That current provided a linear measure of the quantity (S/sub s//sup -2/) = (S/sub 5//sup -2/) + (S/sub 4//sup -2/) +(S/sub 3//sup -2/). Tack 3. enthalpimetric methods development. Assignments of heats of precipitation and solubility products of Tl/sub 2/S, Tl/sub 2/S/sub 2/, Tl/sub 2/S/sub 3/, Tl/sub 2/S/sub 4/, and Tl/sub 2/S/sub 5/ have been compiled from the literature. The molar sum of sulfide and polysulfides has been determined by precipitation titration to a thermometric endpoint with standard thallous nitrate. Task 4. application and technology transfer to coal conversion plants. A polarographic method for determining polysulfides has been validated in a coal liquefaction process stream. The relevant polarographic reduction wave is specific for moieties of the type S/sub x//sup -2/. The hydrosulfide ion HS/sup -/ did not interfere. No cathodic sulfide waves were seen in an H-Coal sour water sample which contained HS/sup -/ but no polysulfides.

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

1981-07-01

288

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 reductase enzyme · Nitrate organic-N · Deficiency symptoms not localized #12;#12;#12;#12;POTENTIAL SULFUR DEFICIENCIES · Low organic matter soils · No recent manure history · Low sulfur in precipitation · Low subsoil

Balser, Teri C.

289

Sulfur isotopes Laura Rosales-Lagarde  

E-print Network

1 Sulfur isotopes Laura Rosales-Lagarde April 9th 2013 Figures from Seal et al. 2000 and Seal 2006 Significance v. 40, 541-602 Seal, R.R. II, 2006, Sulfur Isotope Geochemistry of Sulfide Minerals, in Vaughan D;2 Sulfur species #12;3 Mass-independent fractionation #12;4 #12;5 Sulfur and Oxygen isotopic secular

Lachniet, Matthew S.

290

High pressure-low pressure steam system for extended Claus sulfur recovery plant  

SciTech Connect

This patent describes an improvement in an extended Claus process having at least first, second and third Claus catalytic reactors providing process gas respectively to first, second and third sulfur condensers, the first, second, and third condensers being connected to a steam delivery system. The improvement comprises: producing first pressure steam by directing process gas effective for producing steam at the first pressure from first, second and third catalytic reactors to first, second and third sulfur condensers respectively; producing second pressure steam by directing process gas periodically from one of the first, second and third sulfur condensers to a fourth sulfur condenser; providing cooled process gas from the fourth sulfur condenser to a final position Claus catalytic reactor operated under effective cold bed adsorption conditions.

Pendergraft, P.T.

1991-05-14

291

New insights into Archean sulfur cycle from mass-independent sulfur isotope records from the  

E-print Network

New insights into Archean sulfur cycle from mass-independent sulfur isotope records from of Archean sulfur reservoirs and to trace pathways in the Archean sulfur cycle. Our data are explained-dependent fractionation in the ocean. In the Archean, volcanic, sulfur-bearing gas species were photolysed by solar

292

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.

293

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

294

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2012 CFR

...quality standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection...quality standards for sulfur oxides (sulfur dioxide). (a) The level of the annual...measured in the ambient air as sulfur dioxide by the reference method described...

2012-07-01

295

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

Code of Federal Regulations, 2013 CFR

...quality standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection...quality standard for sulfur oxides (sulfur dioxide). (a) The level of the 3-hour...measured in the ambient air as sulfur dioxide by the reference method described...

2013-07-01

296

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

Code of Federal Regulations, 2011 CFR

...quality standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection...quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national...measured in the ambient air as sulfur dioxide (SO2 ). (b) The 1-hour...

2011-07-01

297

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2010 CFR

...quality standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection...quality standards for sulfur oxides (sulfur dioxide). Link to an amendment published...measured in the ambient air as sulfur dioxide by the reference method described...

2010-07-01

298

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

Code of Federal Regulations, 2010 CFR

...quality standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection...quality standard for sulfur oxides (sulfur dioxide). (a) The level of the 3-hour...measured in the ambient air as sulfur dioxide by the reference method described...

2010-07-01

299

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

Code of Federal Regulations, 2011 CFR

...quality standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection...quality standard for sulfur oxides (sulfur dioxide). (a) The level of the 3-hour...measured in the ambient air as sulfur dioxide by the reference method described...

2011-07-01

300

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2013 CFR

...quality standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection...quality standards for sulfur oxides (sulfur dioxide). (a) The level of the annual...measured in the ambient air as sulfur dioxide by the reference method described...

2013-07-01

301

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

Code of Federal Regulations, 2012 CFR

...quality standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection...quality standard for sulfur oxides (sulfur dioxide). (a) The level of the 3-hour...measured in the ambient air as sulfur dioxide by the reference method described...

2012-07-01

302

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2011 CFR

...quality standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection...quality standards for sulfur oxides (sulfur dioxide). (a) The level of the annual...measured in the ambient air as sulfur dioxide by the reference method described...

2011-07-01

303

Advanced Byproduct Recovery: Direct Catalytic Reduction of Sulfur Dioxide to Elemental Sulfur.  

SciTech Connect

More than 170 wet scrubber systems applied, to 72,000 MW of U.S., coal-fired, utility boilers are in operation or under construction. In these systems, the sulfur dioxide removed from 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). Due to the abundance and low cost of naturally occurring gypsum, and the costs associated with producing an industrial quality product, less than 7% of these scrubbers are configured to produce usable gypsum (and only 1% of all units actually sell the byproduct). The disposal of solid waste from each of these scrubbers requires a landfill area of approximately 200 to 400 acres. In the U.S., a total of 19 million tons of disposable FGD byproduct are produced, transported and disposed of in landfills annually. The use of regenerable sorbent technologies has the potential to reduce or eliminate solid waste production, transportation and disposal. In a regenerable sorbent system, the sulfur dioxide in the boiler flue gas is removed by the sorbent in an adsorber. The S0{sub 2}s subsequently released, in higher concentration, in a regenerator. All regenerable systems produce an off-gas stream from the regenerator that must be processed further in order to obtain a salable byproduct, such as elemental sulfur, sulfuric acid or liquid S0{sub 2}.

NONE

1997-06-01

304

Organic Sulfur and HAP Removal from Coal with Subcritical Water  

SciTech Connect

To date, no economically feasible organic sulfur and hazardous air pollutant (HAP) precursor removal process has been developed; however, an effective sulfur and selected HAP removal process is needed to enhance the utilization of high-sulfur coals and to comply with increasingly stringent regulations. Subcritical water has been shown by the Energy & Environmental Research Center (EERC) researchers on this project to be an extremely effective fluid for the removal of organic sulfur from coals. A multigram reactor designed and built at the EERC for supercritical water extraction was used to scale up from milligram-sized samples to 10-20 grams of coal charge. Work performed during this project year resulted in production of low-sulfur (as low as 0.5% S) extracted coal first at supercritical conditions, i.e., 450{degrees}C and 400 atm (5880 psig), but then at conditions below the critical conditions, i.e., 420{degrees}C and 156 atm (2300 psig). Still milder conditions of 400{degrees}C and 156 atm (2300 psig) resulted in sulfur values similar to those of obtained under the supercritical conditions. IBC-102 extracted with supercritical water had a sulfur value of 0.7 wt%. Extraction of IBC-102 at subcritical conditions of 420{degrees}C and 156 atm (2300 psig) resulted in a sulfur content of 0.490A. The tar obtained from the extracted coal had sulfur values ranging from 1.4 to 6.5 wt% and when treated by catalytic desulfurization, tar was quantitatively recovered with a sulfur value of 0.6 wt%. Float-sink physical cleaning of IBC-102 with Certigrav 1.4 reduced the sulfur content of the coal to 1.5 wt% in a recovered float fraction of 83.3%. Approximately 300 lb of IBC-102 was obtained for use in preparing 100 lb of low-sulfur fuel. Float- sink cleaning on a sample of this new coal returned 87.1 wt% as float fraction, with 1.7 wt% sulfur. 158 lb of physically cleaned IBC-102 was used for the continuous process test on the pilot scale. An additional 150 lb of physically cleaned coal slurry was received from Dr. R. Honaker of southern Illinois University (SIU) for testing in the continuous unit. The hydrothermal process development unit (PDU) in the continuous mode was used to prepare 100 lb of low-sulfur fuel from physically cleaned IBC-102 at three temperatures (300{degrees}, 325{degrees} and 340{degrees}C) and a pressure of 2300 psig. Residence time was controlled by flow rate. Treating a swelling coal such as IBC-102 required a slurry with low solids loading to prevent plugging due to expansion during residence in the reactor. In this preliminary test with physically cleaned IBC-102, the sulfur content was decreased by as much as one-third, few volatiles were lost, and mercury and selenium levels were decreased by 87% and 46%, respectively.

NONE

1996-12-31

305

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.

306

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

307

Preparation and electrochemical properties of lithium-sulfur polymer batteries  

NASA Astrophysics Data System (ADS)

The lithium/sulfur (Li-S) batteries consist of a composite cathode, a polymer electrolyte, and a lithium anode. The composite cathode is made from elemental sulfur (or lithium sulfide), carbon black, PEO, LiClO 4, and acetonitrile. The polymer electrolyte is made of gel-type linear poly(ethylene oxide) (PEO) with tetra ethylene glycol dimethyl ether. Cells based on Li 2S or sulfur have open-circuit voltages of about 2.2 and 2.5 V, respectively. The former cell shows two reduction peaks and one oxidation peak. It is suggested that the first reduction peak is caused by the change from polysulfide to short lithium polysulfide, and the second reduction peak by the change from short lithium polysulfide to lithium sulfide (Li 2S, Li 2S 2). The cell based on sulfur has the same reduction mechanism as that of Li 2S, which is caused by the multi process (first and second reduction) of lithium polysulfide. On charge-discharge cycling, the first discharge has a higher capacity than subsequent discharges and the flat discharge voltage is about 2.0 V. As the current load is increased, the discharge capacity decreases. One reason for this fading capacity and low sulfur utilization is the aggregation of sulfur (or polysulfide) with cycling.

Jeon, Byoung Ho; Yeon, Jin Hee; Kim, Kwang Man; Chung, In Jae

308

RECOVERY OF CALCIUM CARBONATE AND SULFUR FROM FGD SCRUBBER WASTE  

EPA Science Inventory

The report gives results of a demonstration of key process steps in the proprietary Kel-S process for recovering calcium carbonate and sulfur from lime/limestone flue gas desulfurization (FGD) scrubber waste. The steps are: reduction of the waste to calcium sulfide (using coal as...

309

Study of a combined heterotrophic and sulfur autotrophic denitrification technology for removal of nitrate in water  

Microsoft Academic Search

A combined two-step process of heterotrophic denitrification in a fluidized reactor and sulfur autotrophic denitrification processes (CHSAD) was developed for the removal of nitrate in drinking water. In this process, the advantage of high efficiency of heterotrophic denitrification with non-excessive methanol and the advantage of non-pollution of sulfur autotriphic denitrification were integrated in this CHSAD process. And, this CHSAD process

Huijuan Liu; Wei Jiang; Dongjin Wan; Jiuhui Qu

2009-01-01

310

Smaller sulfur molecules promise better lithium-sulfur batteries.  

PubMed

The lithium-sulfur battery holds a high theoretical energy density, 4-5 times that of today's lithium-ion batteries, yet its applications have been hindered by poor electronic conductivity of the sulfur cathode and, most importantly, the rapid fading of its capacity due to the formation of soluble polysulfide intermediates (Li(2)S(n), n = 4-8). Despite numerous efforts concerning this issue, combatting sulfur loss remains one of the greatest challenges. Here we show that this problem can be effectively diminished by controlling the sulfur as smaller allotropes. Metastable small sulfur molecules of S(2-4) were synthesized in the confined space of a conductive microporous carbon matrix. The confined S(2-4) as a new cathode material can totally avoid the unfavorable transition between the commonly used large S(8) and S(4)(2-). Li-S batteries based on this concept exhibit unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior rate capability, which promise a practicable battery with high energy density for applications in portable electronics, electric vehicles, and large-scale energy storage systems. PMID:23101502

Xin, Sen; Gu, Lin; Zhao, Na-Hong; Yin, Ya-Xia; Zhou, Long-Jie; Guo, Yu-Guo; Wan, Li-Jun

2012-11-14

311

A new test procedure for biogenic sulfuric acid corrosion of concrete  

PubMed

A new test method is described for biogenic sulfuric acid corrosion of concrete, more specifically in sewer conditions. The aim of the new test method is the development of an accelerated and reproducible procedure for monitoring the resistance of different types of concrete with regard to biogenic sulfuric acid corrosion. This experimental procedure reflects worst case conditions by providing besides H2S, also an enrichment of thiobacilli and biologically produced sulfur. By simulating the cyclic processes occurring in sewer pipes, significant differences between concrete mixtures could be detected after 51 days. Concrete modified by a styrene-acrylic ester polymer demonstrated a higher resistance against biogenic sulfuric acid attack. PMID:11068828

Vincke; Verstichel; Monteny; Verstraete

1999-01-01

312

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

313

Sulfur dioxide removal from gas streams  

SciTech Connect

A process is described for removal of sulfur dioxide pollutant gas from gas stream which comprises contacting the gas stream with pretreated shale in the form of an aqueous solution of aluminum sulfate including from about 0.1 to about 2.0% by weight of the pretreated shale. The pretreatment of the shale comprises the heating of the shale in the presence of a gas unable to support combustion at a temperature in a range of from about 340/sup 0/C. to about 480/sup 0/C.

Urban, P.; Ginger, E.A.

1986-11-11

314

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

315

Chemical Behavior of Sulfur in Minerals and Silicate Glasses Studied Using Inner Shell Spectroscopy  

Microsoft Academic Search

Understanding the chemical behaviour of sulfur is of fundamental importance in explaining different geological mechanisms ranging from volcano-climatic interactions to the genesis of ore deposits. Understanding how sulphur behaves is also of great economic importance in industrial activities including glass-forming processes and the treatment of vitreous waste material from refuse incineration. The chemical behaviour of sulfur in minerals and glasses

R. Alonso Mori; P. Glatzel; G. Giuli; B. Scaillet

2008-01-01

316

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 pool, increased amounts of gasoline per volume of crude oil and high heats of combustion. The overall

Pike, Ralph W.

317

Synthesis of 1-(2,3-dihydrobenzofuran-3-yl)-methanesulfonohydrazides through insertion of sulfur dioxide.  

PubMed

A three-component reaction of 2-(allyloxy)anilines, sulfur dioxide and hydrazines under mild conditions is developed, which gives rise to 1-(2,3-dihydrobenzofuran-3-yl)-methanesulfonohydrazides in good yields. This radical process involves an intramolecular 5-exo-cyclization and insertion of sulfur dioxide. PMID:25144558

An, Yuanyuan; Zheng, Danqing; Wu, Jie

2014-10-11

318

On the Origin of Sulfur  

E-print Network

We present our work on the halo evolution of sulfur, based on observations of the S I lines around 9220 A for ten stars for which the S abundance was obtained previously from much weaker S I lines at 8694 A. We cannot confirm the rise and the high [S/Fe] abundances for low [Fe/H], as claimed in the literature from analysis of the 8694 A lines. The reasons for claims of an increase in [S/Fe] with decreasing [Fe/H] are probably twofold: uncertainties in the measurements of the weak 8694 A lines, and systematic errors in metallicity determinations from Fe I lines. The near-infrared sulfur triplet at 9212.9, 9228.1, and 9237.5 A are preferred for an abundance analysis of sulfur for metal-poor stars. Our work was presented in full by Ryde & Lambert (2004).

Nils Ryde; David L. Lambert

2005-10-05

319

Biochemistry of Dissimilatory Sulfur Oxidation  

SciTech Connect

The long term goals of this research were to define the substrate oxidation pathways, the electron transport mechanisms, and the modes of energy conservation employed during the dissimilatory oxidation of sulfur practiced by various species of the thiobacilli. Specific adhesion of the thiobacilli to elemental sulfur was studied by electrical impedance, dynamic light scattering, laser Doppler velocimetry, and optical trapping methods. The conclusion is that the thiobacilli appear to express specific receptors that enable the bacteria to recognize and adhere to insoluble sulfur. The enzyme tetrathionate oxidase was purified from two species of the thiobacilli. Extensive structural and functional studies were conducted on adenosine 5'-phosphosulfate reductase purified from cell-free extracts of Thiobacillus denitrificans. The kinetic mechanism of rhodanese was studied.

Blake II, R.

2003-05-30

320

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

321

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

322

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

323

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

NASA Astrophysics Data System (ADS)

Sulfur speciation in a comprehensive set of insoluble organic matter (IOM) samples extracted from 3 CI (Orgueil, Alais, Ivuna), 5 CM (QUE97990, Murchison, Murray, QUE99355, Cold Bokkeveld), 1 CR (Renazzo) and ungrouped C2 Tagish Lake chondrites has been studied by K-edge XANES micro-spectroscopy. Five main sulfur groups were identified: (1) sulfides, (2) aliphatic sulfur, (3) heterocyclic organic sulfur, (4) oxidized organic sulfur and (5) sulfates. The IOM of the 3 CIs and the extensively altered Cold Bokkeveld CM exhibit a higher abundance of heterocyclic versus aliphatic organic sulfur compared to the other CMs and compared to the Renazzo and Tagish Lake chondrites. This suggests greater thermal heating on the parent body of CIs, consistent with the higher temperatures experienced by these chondrites (~ 70 °C for the most altered clasts of Cold Bokkeveld; 100-150 °C for CIs). Alais may have experienced more heating than Ivuna and Orgueil. The IOM of CIs contains oxidized organic sulfur, suggesting the presence of a mild-temperature oxidation process on the parent body. Among type 2 chondrites other than Cold Bokkeveld, no significant variation of the sulfur speciation was detected. This suggests tenuous oxidation processes and a low-temperature aqueous alteration (< ~ 35 °C) on the parent body. The global chemical variations between the CR and CM groups (e.g. H/C elemental ratio, alkyl groups concentration) reported in earlier studies appear to be more the result of chemical variations among the accreted precursors than of post-accretional processes.

Orthous-Daunay, F.-R.; Quirico, E.; Lemelle, L.; Beck, P.; deAndrade, V.; Simionovici, A.; Derenne, S.

2010-12-01

324

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

325

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

326

Thermal behavior of the sulfur electrolyte  

SciTech Connect

Data is included on heats of solid-state transition, heats of fusion and crystallization, heat capacities, DSC endotherms, and the composition range and temperature limits for the sulfur/polysulfide electrolyte in sodium-sulfur batteries.

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

1982-01-01

327

Thermal behavior of the sulfur electrolyte  

Microsoft Academic Search

Data is included on heats of solid-state transition, heats of fusion and crystallization, heat capacities, DSC endotherms, and the composition range and temperature limits for the sulfur\\/polysulfide electrolyte in sodium-sulfur batteries.

G. J. Janz; D. J. Rogers

1982-01-01

328

Behavior of sulfur during coal pyrolysis  

USGS Publications Warehouse

The behavior of sulfur in Illinois coals during pyrolysis was evaluated by thermogravimetry/ Fourier transform-infrared spectroscopy (TG/FT-IR) techniques. SO2, COS, and H2S were major gaseous sulfur-containing products observed during coal pyrolysis. The release rates of the gaseous sulfur species showed several peaks within the temperature ranges, which were due to the emission of different forms of sulfur in coal. ?? 1994.

Shao, D.; Hutchinson, E.J.; Heidbrink, J.; Pan, W.-P.; Chou, C.-L.

1994-01-01

329

The effect of elemental sulfur, gypsum and ammonium thiosulfate as sulfur sources on yield of rapeseed  

Microsoft Academic Search

A growth chamber experiment was conducted to compare ammonium thiosulfate, gypsum and elemental sulfur in the form of Agrisul as sources of sulfur for rapeseed (Brassica napus var. Regent). Rapeseed supplied with ammonium thiosulfate or gypsum produced significantly higher yields than treatments supplied with elemental sulfur. Powdering and mixing of elemental sulfur, as opposed to banding granules, significantly increased dry

M. Swan; R. J. Soper; G. Morden

1986-01-01

330

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

331

December 2002 Issue #13 2002 SULFUR RESPONSES AND THE WISCONSIN ALFALFA SULFUR  

E-print Network

December 2002 Issue #13 ­ 2002 SULFUR RESPONSES AND THE WISCONSIN ALFALFA SULFUR SURVEY 1/ K to applied sulfur fertilizer in northern and western Wisconsin on lighter textured, low organic matter soils and Kelling, 1987). More recently, crop consultants and others have reported seeing sulfur responses on soils

Balser, Teri C.

332

Sulfur Economy and Cell Wall Biosynthesis during Sulfur Limitation of Chlamydomonas reinhardtii1  

E-print Network

Sulfur Economy and Cell Wall Biosynthesis during Sulfur Limitation of Chlamydomonas reinhardtii1 that specifically accumulate during sulfur limitation of Chlamydomonas reinhardtii. These polypeptides, present at high levels in the extracellular polypeptide fraction from a sulfur-deprived, cell wall-minus C

333

Chemistry of Sulfur Oxides on Transition Metals. II. Thermodynamics of Sulfur Oxides on Platinum(111)  

E-print Network

Chemistry of Sulfur Oxides on Transition Metals. II. Thermodynamics of Sulfur Oxides on Platinum at the highest coverages and sulfur oxidation states. Calculated vibrational spectra are used to assign observed the preferred SOx species on Pt(111), consistent with observation. I. Introduction The chemistry of sulfur

Lin, Xi

334

Parallel, high-resolution carbon and sulfur isotope records of the evolving Paleozoic marine sulfur reservoir  

E-print Network

Parallel, high-resolution carbon and sulfur isotope records of the evolving Paleozoic marine sulfur the biogeochemical cycles of carbon and sulfur are expressed in the evolving stable isotope composition of the ocean time, along with the sulfate sulfur isotope composition preserved as carbonate-associated sulfate (CAS

Saltzman, Matthew R.

335

Chemistry of ascorbic acid and sulfur dioxide as an antioxidant system relevant to white wine.  

PubMed

The impact of the combined ascorbic acid and sulfur dioxide antioxidants on white wine oxidation processes was investigated using a range of analytical techniques, including flow injection analysis for free and total sulfur dioxide and two chromatographic methods for ascorbic acid, its oxidative degradation products and phenolic compounds. The combination of different analytical techniques provided a fast and simultaneous means for the monitoring of oxidation processes in a model wine system. In addition, the initial mole ratio of sulfur dioxide to ascorbic acid was varied and the model wine complexity was increased by the inclusion of metal ions (copper(II) and iron(II)). Sulfur dioxide was found not to be a significant binder of ascorbic acid oxidative degradation products and could not prevent the formation of certain phenolic pigment precursors. The results provide a detailed insight into the ascorbic acid/sulfur dioxide antioxidant system in wine conditions. PMID:22688051

Barril, Célia; Clark, Andrew C; Scollary, Geoffrey R

2012-06-30

336

Hydrogen and sulfur production from hydrogen sulfide wastes  

SciTech Connect

A new hydrogen sulfide waste-treatment process that uses microwave plasma-chemical technology is currently under development in the Soviet Union and in the United States. Whereas the present waste treatment process only recovers sulfur at best, this novel process recovers both hydrogen and sulfur. The plasma process involves dissociating hydrogen sulfide in a ``nonequilibrium`` plasma in a microwave or radio-frequency reactor. After the dissociation process, sulfur is condensed and sold just as is currently done. The remaining gases are purified and separated into streams containing the product hydrogen, the hydrogen sulfide to be recycled to the plasma reactor, and the process purge containing carbon dioxide and water. This process has particular implications for the petroleum refining industry, in which hydrogen is a widely used reagent and must be produced from increasingly scarce hydrocarbon resources. The modular nature of the new process may also offer economic advantages over small-scale waste treatment technologies widely used in the natural-gas industry. Laboratory-scale experiments with pure hydrogen sulfide indicate that conversions exceeding 90% are possible with appropriate reactor design and that the energy required to dissociate hydrogen sulfide is low enough for the plasma process to be economically competitive. In addition, the experiments show that typical refinery acid-gas streams are compatible with the plasma process and that all by-products can be treated with existing technology.

Harkness, J.B.L.; Doctor, R.D.

1993-03-01

337

Hydrogen and sulfur production from hydrogen sulfide wastes  

SciTech Connect

A new hydrogen sulfide waste-treatment process that uses microwave plasma-chemical technology is currently under development in the Soviet Union and in the United States. Whereas the present waste treatment process only recovers sulfur at best, this novel process recovers both hydrogen and sulfur. The plasma process involves dissociating hydrogen sulfide in a nonequilibrium'' plasma in a microwave or radio-frequency reactor. After the dissociation process, sulfur is condensed and sold just as is currently done. The remaining gases are purified and separated into streams containing the product hydrogen, the hydrogen sulfide to be recycled to the plasma reactor, and the process purge containing carbon dioxide and water. This process has particular implications for the petroleum refining industry, in which hydrogen is a widely used reagent and must be produced from increasingly scarce hydrocarbon resources. The modular nature of the new process may also offer economic advantages over small-scale waste treatment technologies widely used in the natural-gas industry. Laboratory-scale experiments with pure hydrogen sulfide indicate that conversions exceeding 90% are possible with appropriate reactor design and that the energy required to dissociate hydrogen sulfide is low enough for the plasma process to be economically competitive. In addition, the experiments show that typical refinery acid-gas streams are compatible with the plasma process and that all by-products can be treated with existing technology.

Harkness, J.B.L.; Doctor, R.D.

1993-01-01

338

Modulation of the Midpoint Potential of the [2Fe-2S] Rieske Iron Sulfur Center by Qo Occupants in the bc1 Complex  

E-print Network

Modulation of the Midpoint Potential of the [2Fe-2S] Rieske Iron Sulfur Center by Qo Occupants the immediate donor to c1, the Rieske iron-sulfur protein (ISP). Because the effect was seen only over, and an iron-sulfur center, ISP1) and two quinone-processing sites, for oxidation of ubiquinol (Qo site

Crofts, Antony R.

339

Sulfur dynamics in an impoundment receiving acid mine drainage  

SciTech Connect

To quantify the importance of bacterial sulfate reduction (SR) in an acidified system, a sulfate influx-efflux budget was constructed for Lake Anna, an impoundment receiving acid mine drainage. Forty eight percent of the entering sulfate was removed from the water column within the 2 km arm of the lake that receives the pollution. Directly measured SR equaled 200% of the sulfate removal calculated in the budget. Thus, sulfide oxidation must be an important process in these sediments. The calculated alkalinity generated by sulfate removal was more than twice that necessary to account for the observed pH increase in the impoundment. Inorganic sulfur concentrations in the sediments of the impacted arm of Lake Anna were significantly greater than those in unpolluted sections of the lake. Label experiments showed that FeS and elemental sulfur (S{degree}) were the major products of SR in the impacted sediments. Inorganic sulfur (FeS, S{degree}, and pyrite) made up to 60% to 100% of the total sediment sulfur concentration. Pyrite concentrations were high and decreased exponentially with distance from the AMD source, indicating that the pyrite is stream detrius. FeS and S{degree} concentrations were highest at a station 1 km away from the AMD inflow, indicating in situ formation. There was no evidence for the formation of organic sulfur species.

Herlihy, A.T.

1987-01-01

340

CONTROL OF SULFUR EMISSIONS FROM OIL SHALE RETORTS  

EPA Science Inventory

The objectives of this study were to determine the best available control technology (BACT) for control of sulfur emissions from oil shale processing facilities and then to develop a design for a mobile slipstream pilot plant that could be used to test and demonstrate that techno...

341

Sulfur gas analysis in the pulp and paper industry  

SciTech Connect

Various techniques of determining total reduced sulfur (TRS) gases that are emitted in the manufacture of pulp and paper, particularly in the kraft pulping process, are reviewed. Particular emphasis is placed on two types of popular TRS analyzers used in Canada, viz. coulometers and gas chromatographs, with a discussion on the automation of the latter.

de Souza, T.L.C.

1988-06-01

342

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...

343

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...

344

Aminosulfonylation of aromatic amines, sulfur dioxide and hydrazines.  

PubMed

A facile route to aryl N-aminosulfonamides under mild conditions is provided. The reaction of aromatic amines (including heteroaromatic amines), sulfur dioxide, and hydrazines proceeds efficiently with good functional group tolerance. The in situ generated diazonium ion is involved in the aminosulfonylation process. PMID:24970100

Zheng, Danqing; Li, Ying; An, Yuanyuan; Wu, Jie

2014-08-18

345

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

346

The sulfur isotope composition of basaltic rocks  

Microsoft Academic Search

The sulfur isotope composition of tholeiitic basalts, olivine alkali basalts and alkalirich undersaturated basalts were investigated. A method of preparation was devised(a)for the extraction of the small amounts of sulfur contained in the rock samples (about 100 ppm S),(b)for the separation of sulfide- and sulfate-sulfur.

Alfred Schneider

1970-01-01

347

Geological evolution from isotope proxy signals — sulfur  

Microsoft Academic Search

A currently emerging sulfur isotope record for Phanerozoic seawater, based on structurally substituted sulfate in stratigraphically well constrained biogenic carbonates, allows the detailed assessment of secular variations within the global sulfur cycle and the interaction between the sulfur and carbon cycles. It is superior to the evaporite-based dataset because it enables sampling of the entire biostratigraphic column. Discrete biological and

Harald Strauss

1999-01-01

348

Two stage sorption of sulfur compounds  

SciTech Connect

A two stage method for reducing the sulfur content of exhaust gases is disclosed. Alkali- or alkaline-earth-based sorbent is totally or partially vaporized 10 and introduced into a sulfur-containing gas stream. The activated sorbent can be introduced in the reaction zone or the exhaust gases of a combustor or a gasifier. High efficiencies of sulfur removal can be achieved.

Moore, W.E.

1991-12-31

349

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.

350

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Sulfur. 148.315 Section 148.315 Shipping...for Certain Materials § 148.315 Sulfur. (a) This part applies to lump or coarse grain powder sulfur only. Fine-grained powder...

2013-10-01

351

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Sulfur. 148.315 Section 148.315 Shipping...for Certain Materials § 148.315 Sulfur. (a) This part applies to lump or coarse grain powder sulfur only. Fine-grained powder...

2012-10-01

352

Two stage sorption of sulfur compounds  

DOEpatents

A two stage method for reducing the sulfur content of exhaust gases is disclosed. Alkali- or alkaline-earth-based sorbent is totally or partially vaporized and introduced into a sulfur-containing gas stream. The activated sorbent can be introduced in the reaction zone or the exhaust gases of a combustor or a gasifier. High efficiencies of sulfur removal can be achieved.

Moore, William E. (Manassas, VA)

1992-01-01

353

46 CFR 148.315 - Sulfur.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Sulfur. 148.315 Section 148.315 Shipping...for Certain Materials § 148.315 Sulfur. (a) This part applies to lump or coarse grain powder sulfur only. Fine-grained powder...

2011-10-01

354

Process development in removing sulfur dioxide from hot flue gases (in four parts). III. Pilot plant study of the alkalized alumina system for SOâ removal. [625°F  

Microsoft Academic Search

The use of alkalized alumina in removing sulfur dioxide from a coal-combustion flue gas at 625°F was investigated on a pilot plant scale. The absorber was 26 feet long and 1.6 inches ID. Countercurrent gas-solids flow at gas velocities of 8 to 15 ft\\/sec in the presence and absence of baffles, as well as solids entrainment at gas velocities of

D. Beinstock; J. H. Field; J. G. Myers

1967-01-01

355

Biochemistry of dissimilatory sulfur oxidation  

SciTech Connect

Our goals of this research are to define the substrate oxidation pathways, the electron transport mechanisms, and the modes of energy conservation employed during the dissimilatory oxidation of sulfur by thiobacilli. We have purified APS reductase to electrophoratic homogeneity from cell-free extracts of Thiobacillus denitrificans. Sufficient protein is available to initiate the production of polyclonal antibodies and to perform the kinetic experiments.

Blake, R. II.

1992-01-01

356

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

357

TRENDS IN RURAL SULFUR CONCENTRATIONS  

EPA Science Inventory

This paper presents an analysis of regional trends in atmospheric concentrations in sulfur dioxide (502) and particulate sulfate (50~- ) at rural monitoring sites in the Clean Air Act Status and Trends Monitoring Network (CAsTNet) from 1990 to 1999. A two-stage approach is used t...

358

Sulfur Dioxide and Material Damage  

ERIC Educational Resources Information Center

This study relates sulfur dioxide levels with material damage in heavily populated or polluted areas. Estimates of loss were determined from increased maintenance and replacement costs. The data indicate a decrease in losses during the past five years probably due to decline in pollution levels established by air quality standards. (MR)

Gillette, Donald G.

1975-01-01

359

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...

360

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

361

Sulfur isotope distribution in solfatares, Yellowstone National Park  

USGS Publications Warehouse

Sulfur isotope data on hydrogen sulfide, native sulfur, and sulfates from acid hot-spring areas at Yellowstone National Park suggest that hydrogen sulfide oxidizes to sulfur analogically, whereas sulfur undergoes biological oxidation to sulfuric acid. An exception occurs at Mammoth Hot Springs where hydrogen sulfide apparently undergoes biochemical oxidation to sulfur.

Schoen, R.; Rye, R.O.

1970-01-01

362

Annealing Temperature Dependence of Properties of Cu2ZnSnS4 Thin Films Prepared by Sol--Gel Sulfurization Method  

Microsoft Academic Search

Cu2ZnSnS4 (CZTS) thin films were fabricated by a sol--gel sulfurization method with a rapid thermal process. The films preheated at 250 °C for 1 h and sulfurized from 350 to 600 °C for 1 h were investigated. The chemical composition of sulfur was 40% for the preheated film and 50% for the films sulfurized at temperatures higher than 400 °C.

Kazuya Maeda; Kunihiko Tanaka; Yuya Nakano; Hisao Uchiki

2011-01-01

363

Sulfur-oxidizing Bacteria: A Novel Bioinoculant for Sulfur Nutrition and Crop Production  

Microsoft Academic Search

\\u000a Sulfur is an essential nutrient for plant growth as sulfur-deficient conditions cause severe losses in crop yield. Sulfur\\u000a nutrition has received little attention for many years, since fertilizers and atmospheric inputs have provided adequate amounts.\\u000a However, recent reductions in sulfur inputs from atmospheric depositions have resulted in a negative sulfur balance in agricultural\\u000a soils, making crop plants increasingly dependent on

R. Anandham; P. Indira Gandhi; M. SenthilKumar; R. Sridar; P. Nalayini; Tong-Min Sa

364

Direct sulfur recovery during sorbent regeneration. Final report  

SciTech Connect

The objective of this research project was to improve the direct elemental sulfur yields that occur during the regeneration of SO{sub 2}-saturated MgO-vermiculite sorbents (MagSorbents) by examining three approaches or strategies. The three approaches were regeneration-gas recycle, high-pressure regeneration, and catalytic reduction of the SO{sub 2} gas using a new catalyst developed by Research Triangle Institute (RTI). Prior to the project, Sorbent Technologies Corporation (Sorbtech) had developed a sorbent-regeneration process that yielded directly a pure elemental sulfur product. In the process, typically about 25 to 35 percent of the liberated S0{sub 2} was converted directly to elemental sulfur. The goal of this project was to achieve a conversion rate of over 90 percent. Good success was attained in the project. About 90 percent or more conversion was achieved with two of the approaches that were examined, regeneration-gas recycle and use of the RTI catalyst. Of these approaches, regeneration-gas recycle gave the best results (essentially 100 percent conversion in some cases). In the regeneration-gas recycle approach, saturated sorbent is simply heated to about 750{degree}C in a reducing gas (methane) atmosphere. During heating, a gas containing elemental sulfur, water vapor, H{sub 2}S, S0{sub 2}, and C0{sub 2} is evolved. The elemental sulfur and water vapor in the gas stream are condensed and removed, and the remaining gas is recycled back through the sorbent bed. After several recycles, the S0{sub 2} and H{sub 2}S completely disappear from the gas stream, and the stream contains only elemental sulfur, water vapor and C0{sub 2}.

Nelson, S.G.; Little, R.C. [Sorbent Technologies Corp., Twinsburg, OH (United States)

1993-08-01

365

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, Clement; Giuliani, Marie-Cecile; Infossi, Pascale; Lojou, Elisabeth; Guiral, Marianne; Giudici-Orticoni, Marie-Therese; Ilbert, Marianne

2012-01-01

366

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

367

Heterogeneous Photochemical Oxidation of Sulfur Dioxide  

NASA Astrophysics Data System (ADS)

The gas phase oxidation of sulfur dioxide by the hydroxyl radical is a significant source of sulfate aerosol in the troposphere and stratosphere. Stockwell and Calvert (1983) performed fifteen chamber experiments where mixtures of HONO, NO, NO2, H2O, SO2 and CO were photolyzed in synthetic air or in nitrogen containing approximately 50 ppm oxygen. They found that the atmospheric oxidation of SO2 by hydroxyl radical was a chain process that occurs through the production of an HO2 radical followed by reaction with NO to reproduce HO. We have reanalyzed this dataset and we have found that a very large amount of the observed SO2 oxidation (70.0 ± 9.1 %) is not explained through the HO + SO2 reaction alone. The Regional Atmospheric Chemistry Mechanism (RACM2) was used to investigate additional chemical pathways for the oxidation of SO2. A mechanism consisting of photochemical heterogeneous reactions is proposed to account for the observed additional sulfur dioxide oxidation not accounted for by gas phase oxidation. The analysis showed that the measured time dependent SO2, CO2 and nitrogenous compound concentrations could be simulated by the photochemical heterogeneous mechanism in conjunction with the RACM2 mechanism.

El-Zanan, H. S.; Stockwell, W. R.

2007-12-01

368

Annealing Temperature Dependence of Properties of Cu2ZnSnS4 Thin Films Prepared by Sol-Gel Sulfurization Method  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) thin films were fabricated by a sol-gel sulfurization method with a rapid thermal process. The films preheated at 250 °C for 1 h and sulfurized from 350 to 600 °C for 1 h were investigated. The chemical composition of sulfur was 40% for the preheated film and 50% for the films sulfurized at temperatures higher than 400 °C. The grain size of the films markedly increased with increasing sulfurization temperature from 400 to 450 °C and that of the films sulfurized at temperatures higher than 450 °C was ˜2 µm. The preheated film and the films sulfurized at temperatures lower than 400 °C were composed of CuxS and CZTS. The CuxS phase was eliminated from the CZTS films by sulfurization at temperatures higher than 500 °C.

Maeda, Kazuya; Tanaka, Kunihiko; Nakano, Yuya; Uchiki, Hisao

2011-05-01

369

Sulfur metabolism in Escherichia coli and related bacteria: facts and fiction.  

PubMed

Living organisms are composed of macromolecules made of hydrogen, carbon, nitrogen, oxygen, phosphorus and sulfur. Much work has been devoted to the metabolism of the first five elements, but much remains to be understood about sulfur metabolism. We review here the situation in Escherichia coli and related bacteria, where more than one hundred genes involved in sulfur metabolism have already been discovered in this organism. Examination of the genome suggests that many more will be found, especially genes involved in regulation, scavenging of sulfur containing molecules and synthesis of coenzymes or prosthetic groups. Furthermore, the involvement of methionine as the universal start of proteins as well as that of its derivative S-adenosylmethionine in a vast variety of cell processes argue in favour of a major importance of sulfur metabolism in all organisms. PMID:10939241

Sekowska, A; Kung, H F; Danchin, A

2000-04-01

370

Sulfur analyses as tracers of microbial degradation of hydrocarbons in the capillary fringe  

NASA Astrophysics Data System (ADS)

Analyses of solid-phase sulfur species in soil cores indicate the role of sulfur redox cycling in the fate of a BTEX-rich natural gas condensate plume in a silt-clay aquitard at a gas well site in Alberta, Canada. These analyses confirmed that sulfate reduction has been a key anaerobic electron-accepting process in the plume. The observed concentrations (?g/g sediment) of the reduced solid-phase sulfur components provided evidence regarding the quantity of sulfate that has been reduced over time, and the extent of hydrocarbon plume degradation. The spatial distribution of these phases indicates that degradation of petroleum hydrocarbons linked to sulfate reduction was focused in the capillary fringe, where sulfides and elemental sulfur were the main inorganic sulfur species produced as a result of sulfate reduction.

Van Stempvoort, Dale R.; Kwong, Y. T. John

2010-05-01

371

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

372

Transporters in plant sulfur metabolism  

PubMed Central

Sulfur is an essential nutrient, necessary for synthesis of many metabolites. The uptake of sulfate, primary and secondary assimilation, the biosynthesis, storage, and final utilization of sulfur (S) containing compounds requires a lot of movement between organs, cells, and organelles. Efficient transport systems of S-containing compounds across the internal barriers or the plasma membrane and organellar membranes are therefore required. Here, we review a current state of knowledge of the transport of a range of S-containing metabolites within and between the cells as well as of their long distance transport. An improved understanding of mechanisms and regulation of transport will facilitate successful engineering of the respective pathways, to improve the plant yield, biotic interaction and nutritional properties of crops.

Gigolashvili, Tamara; Kopriva, Stanislav

2014-01-01

373

Economical nitrogen—sulfur fluids  

Microsoft Academic Search

The National Fertilizer & Environmental Research Center (NFERC) has developed and begun introduction of a new family of nitrogen—sulfur (NS) suspensions with several advantages. The new NS suspensions have a substantial economic advantage over ammonium thiosulfate-based solutions and they are considerably higher in grade and more versatile than ammonium sulfate-based solutions currently on the market. In some areas, the NS

J. L. Boles; C. A. Hodge; L. C. Faulkner

1991-01-01

374

Sulfur emissions from Mt. Etna  

Microsoft Academic Search

In the course of three measuring trips to the Mt. Etna volcano (Sicily), field measurements and measurements by aircraft were carried out in the plume of the volcano to determine the concentration distributions and emission rates for the sulfur compounds H2S, SO2, and SO42-. Furthermore, the removal of H2S and SO2 and the production of SO42- in the dispersing plume

Wolfgang Jaeschke; Harald Berresheim; Hans-W. Georgii

1982-01-01

375

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

376

Influence of sulfur in coals on char morphology and combustion  

SciTech Connect

During coal carbonization (pyrolysis), as during the combustion process of pulverized coal in a combustor, not all of the sulfur is released. Significant proportions become pat of the structure of the resultant coke and char. The combustion process of the char within the flames of the combustor in influenced dominantly by char morphology. This, in turn, controls the accessibility of oxidizing gases to the surfaces of the carbonaceous substance of the char. Mineral matter content, its extent and state of distribution, also exerts an influence on char morphology created during pyrolysis/carbonization. This complexity of coal renders it a very difficult material to study, systematically, to distinguish and separate out the contributing factors which influence combustion characteristics. Therefore, in such circumstances, it is necessary to simplify the systems by making use of model chars/cokes/carbons which can be made progressively more complex, but in a controlled way. In this way complicating influence in chars from coals can be eliminated, so enabling specific influences to be studied independently. It is important to note that preliminary work by Marsh and Gryglewicz (1990) indicated that levels of sulfur of about 3 to 5 wt % can reduce reactivities by 10 to 25%. The overall purpose of the study is to provide meaningful kinetic data to establish, quantitatively, the influence of organically-bound sulfur on the reactivity of carbons, and to ascertain if gasification catalysts are effective in the preferential removal of sulfur from the chars.

Marsh, H.

1991-01-01

377

Removal of sulfur and HAPs from coal using water extraction  

SciTech Connect

To date, no economically feasible process for organic sulfur and hazardous air pollutant (HAP) precursor removal from coal has been developed. However, a hydrothermal method based on supercritical water extraction techniques developed at the University of North Dakota Energy and Environmental Research Center (UNDEERC) with support from the Illinois Clean Coal Institute (ICCI), USDOE and the Center for Air Toxic Metals (CATM) has shown promise. Analytical (milligram) scale supercritical water extraction of sulfur from Illinois high sulfur bituminous coals were used to evaluate the sulfur and HAPs removal effectiveness of the process. Multigram extractions were used to establish effective conditions, and the multi-kilogram pilot scale extraction provided evidence of the scale-up potential of the technology. Tests at the multigram scale resulted in production of low sulfur (as low as 0.5% S, mf) coal solids, first, at supercritical conditions, e.g., 450 C and 400 atm (5,880 psig), then at conditions below the critical pressure, e.g., 420 C and 156 atm (2,300 psig). Even milder conditions of 400 C and 156 atm (2,300 psig) resulted in sulfur values of 0.8% S. IBC-102 containing 3.1% S was extracted with supercritical water resulting in a sulfur value of 0.7 wt% in the recovered solids. Extraction of IBC-102 at subcritical pressure of 420 C and 156 atm (2,300 psi) resulted in a sulfur content of 0.49%. The tar obtained from extracted coal had sulfur values ranging from 1.4 wt% to 6.5 wt%, but when treated by catalytic desulfurization, was quantitatively recovered with a sulfur value of 0.6 wt%. Selected HAP (Se, Hg, Cd, Cl) removal from IBC coals resulted in decreases of as much as 57% of the Se, 99% of Hg, 85% of As, and 73% of Cl in coal solids, but was determined to be coal dependent. Freshly mined coals were also tested and gave similar results. In later tests emphasis was on hydrothermal treatment of physically cleaned coal. Batch testing on the pilot scale, which consisted of hydrothermal treatment of physically cleaned freshly mined Illinois coal followed by on-line catalytic desulfurization of the tar, resulted in a reconstituted product which was easily briquetted. Analysis showed the briquettes to have 1.6% S (1.2% organic sulfur), 3.7% ash and a heating value of 14,475 Btu/lb. The focus of the economic evaluation has been primarily on the coal cleaning. The cost effectiveness of conventional coal cleaning, froth flotation, selective agglomeration, and hydrothermal treatment have been preliminarily compared. The primary cost of coal cleaning incurred by the utility company is an incremental increase in the price of fuel. This can range from $2 to over $30 per ton of coal. Coal cleaning, however, also offers a number of benefits to the utility in the form of lower SO{sub 2} emissions, lower operating and maintenance costs resulting from reduced ash content, and lower waste disposal costs. Of the advanced coal cleaning methods, the hydrothermal treatment shows the most promise, both in terms of achievable mercury levels, and in cost. Taking a credit of $100/ton SO{sub 2} removed, the cost of mercury removal ranged from $40,000 to $84,000/lb Hg removed. This is within the range of costs of $4,920 to $70,000/lb Hg removed presented by EPA in its recent report to congress as the projected cost of mercury control in utility applications. Future work at the EERC will focus on optimizing the hydrothermal treatment process and developing more accurate cost estimates.

Timpe, R.; Mann, M. [Energy and Environmental Research Center (United States); Ho, K. [Illinois Clean Coal Inst., IL (United States)

1998-12-31

378

Sulfur-impregnated disordered carbon nanotubes cathode for lithium-sulfur batteries.  

PubMed

The commercialization of lithium-sulfur batteries is hindered by low cycle stability and low efficiency, which are induced by sulfur active material loss and polysulfide shuttle reaction through dissolution into electrolyte. In this study, sulfur-impregnated disordered carbon nanotubes are synthesized as cathode material for the lithium-sulfur battery. The obtained sulfur-carbon tube cathodes demonstrate superior cyclability and Coulombic efficiency. More importantly, the electrochemical characterization indicates a new stabilization mechanism of sulfur in carbon induced by heat treatment. PMID:21928817

Guo, Juchen; Xu, Yunhua; Wang, Chunsheng

2011-10-12

379

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

380

Metabolism of sulfur amino acids in Saccharomyces cerevisiae.  

PubMed Central

Sulfur amino acid biosynthesis in Saccharomyces cerevisiae involves a large number of enzymes required for the de novo biosynthesis of methionine and cysteine and the recycling of organic sulfur metabolites. This review summarizes the details of these processes and analyzes the molecular data which have been acquired in this metabolic area. Sulfur biochemistry appears not to be unique through terrestrial life, and S. cerevisiae is one of the species of sulfate-assimilatory organisms possessing a larger set of enzymes for sulfur metabolism. The review also deals with several enzyme deficiencies that lead to a nutritional requirement for organic sulfur, although they do not correspond to defects within the biosynthetic pathway. In S. cerevisiae, the sulfur amino acid biosynthetic pathway is tightly controlled: in response to an increase in the amount of intracellular S-adenosylmethionine (AdoMet), transcription of the coregulated genes is turned off. The second part of the review is devoted to the molecular mechanisms underlying this regulation. The coordinated response to AdoMet requires two cis-acting promoter elements. One centers on the sequence TCACGTG, which also constitutes a component of all S. cerevisiae centromeres. Situated upstream of the sulfur genes, this element is the binding site of a transcription activation complex consisting of a basic helix-loop-helix factor, Cbf1p, and two basic leucine zipper factors, Met4p and Met28p. Molecular studies have unraveled the specific functions for each subunit of the Cbf1p-Met4p-Met28p complex as well as the modalities of its assembly on the DNA. The Cbf1p-Met4p-Met28p complex contains only one transcription activation module, the Met4p subunit. Detailed mutational analysis of Met4p has elucidated its functional organization. In addition to its activation and bZIP domains, Met4p contains two regulatory domains, called the inhibitory region and the auxiliary domain. When the level of intracellular AdoMet increases, the transcription activation function of Met4 is prevented by Met30p, which binds to the Met4 inhibitory region. In addition to the Cbf1p-Met4p-Met28p complex, transcriptional regulation involves two zinc finger-containing proteins, Met31p and Met32p. The AdoMet-mediated control of the sulfur amino acid pathway illustrates the molecular strategies used by eucaryotic cells to couple gene expression to metabolic changes. PMID:9409150

Thomas, D; Surdin-Kerjan, Y

1997-01-01

381

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

382

A Combined Proteomic and Transcriptomic Analysis on Sulfur Metabolism Pathways of Arabidopsis thaliana under Simulated Acid Rain  

PubMed Central

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

Wang, Wenhua; Simon, Martin; Wu, Feihua; Hu, Wenjun; Chen, Juan B.; Zheng, Hailei

2014-01-01

383

Oxygen and sulfur interactions with a clean iron surface and the effect of rubbing contact on these interactions  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the nature of the chemical interactions of oxygen and sulfur with iron when surfaces are stationary and also during sliding in a vacuum environment. Various gases that contained sulfur, oxygen, or both were adsorbed to iron at 23 C. The gases included oxygen, hydrogen sulfide, methyl mercaptan, and sulfur dioxide. Friction experiments were conducted with a hemispherical rider sliding on a rotating disk. An Auger cylindrical mirror analyzer was used to monitor the iron surface chemistry. The results of this study indicate that oxygen will completely displace sulfide films from iron surfaces. Organic thiols containing sulfur, such as methyl mercaptan, adsorb to an iron surface dissociatively. Only sulfur is detected on the iron surface. Sliding inhibits the formation of sulfide films on iron with the adsorption of hydrogen sulfide and methyl mercaptan. With oxygen and sulfur dioxide, the sliding process does not affect adsorption behavior.

Buckley, D. H.

1973-01-01

384

Sulfur Contents of Planetary and Protoplanetary Cores  

NASA Astrophysics Data System (ADS)

Sulfur is an important component of protoplanetary cores, as indicated by the presence of sulfides in iron meteorites, as well as the trace element distributions within iron groups that indicate a fractional crystallization process between metal and coexisting sulfide melt. However, sulfur in the Earth’s core is expected to be limited to 2 percent or lower, as indicated by the volatility trend of elements in the bulk Earth (Dreibus and Palme, 1996; McDonough, 2003). This follows an assumption that the order of element volatilities determined in condensation calculations for the solar nebula is also appropriate to the devolatilization of planetary bodies such as the Earth, although planets may have devolatilized by non-nebular processes. The assumption can be evaluated by applying the same logic to the iron meteorites as has been applied to the Earth; the irons exhibit volatility depletions among trace siderophile elements that are similar or greater than the volatile depletions in Earth. Estimates of S content in parent metallic melts have been reported for the IIAB, IID, IIIAB, IVA, and IVB iron meteorite groups (e.g., Chabot, 2004; Wasson and Huber, 2006). Although there are discrepancies between some models, in most cases one finds that the cosmochemical estimates of S abundance in these protoplanetary cores are significantly higher than would be expected on the basis of their volatility trends. For example, CI-normalized S/Ge ratios exceed 100 in some cases. Unless the crystallization models applied to the iron meteorite groups are inaccurate, the assumptions behind the construction of the volatility trends appear to be violated for S in protoplanets (and by extension larger planets, including Earth). Hence, it remains plausible on cosmochemical grounds that Earth’s core is S-rich. Gas speciation and partial pressures in the impact plumes produced during planet formation are very different than those in the low-density, hydrogen-rich solar nebula, and should generate a different volatilization-condensation sequence.

Campbell, A. J.

2009-12-01

385

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

386

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

387

Contribution of isotopologue self-shielding to sulfur mass-independent fractionation during sulfur dioxide photolysis  

E-print Network

Signatures of sulfur mass-independent fractionation (S-MIF) are observed for sulfur minerals in Archean rocks, and for modern stratospheric sulfate aerosols (SSA) deposited in polar ice. Ultraviolet light photolysis of ...

Lyons, J. R.

388

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

389

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

390

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

391

Microbiological fractionation of stable sulfur isotopes: A review and critique  

Microsoft Academic Search

Microbiological transformations of sulfur compounds discriminate to various degrees between the stable sulfur isotopes S and S. Comparatively little is known on isotopic effects associated with sulfur?oxidizing organisms, and the interpretation of results is complicated since the sulfur pathways are poorly defined and compounds containing two or more sulfur atoms at different oxidation states may be involved. Dissimilatory reduction of

L. A. Chambers; P. A. Trudinger

1979-01-01

392

Structural insight into the mode of interactions of SoxL from Allochromatium vinosum in the global sulfur oxidation cycle.  

PubMed

Microbial redox reactions of inorganic sulfur compounds are one of the important reactions for the recycling of sulfur to maintain the environmental sulfur balance. These reactions are carried out by phylogenetically diverse microorganisms. The sulfur oxidizing gene cluster (sox) of ?-proteobacteria, Allochromatium vinosum comprises two divergently transcribed units. The central players of this process are SoxY, SoxZ and SoxL. SoxY is sulfur compound binder which binds to sulfur anions with the help of SoxZ. SoxL is a rhodanese like protein, which then cleaves off the sulfur substrate from the SoxYZ complex to recycle the SoxY and SoxZ. In the present work, homology modeling has been employed to build the three dimensional structures of SoxY, SoxZ and SoxL. With the help of docking simulations the amino acid residues of these proteins involved in the interactions have been identified. The interactions between the SoxY, SoxZ and SoxL proteins are mediated mainly through hydrogen bonding. Strong positive fields created by the SoxZ and SoxL proteins are found to be responsible for the binding and removal of the sulfur anion. The probable biochemical mechanism of sulfur anion oxidation process has been identified. PMID:23053932

Bagchi, Angshuman

2012-12-01

393

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

394

Testing and evaluation of polyethylene and sulfur cement waste forms  

SciTech Connect

This paper discusses the results of recent studies related to the use of polyethylene and modified sulfur cement as new binder materials for the improved solidification of low-level wastes. Waste streams selected for this study include those which result from advanced volume reduction technologies (dry evaporator concentrate salts and incinerator ash) and those that remain problematic for solidification using contemporary agents (ion-exchange resins). Maximum waste loadings were determined for each waste type. Recommended waste loadings of 70 wt % sodium sulfate, 50 wt % boric acid, 40 wt % incinerator ash and 30 wt % ion exchange resins, which are based on process control and waste form performance considerations are reported for polyethylene. For sulfur cement the recommended waste loadings of 40 wt % sodium sulfate and boric acid salts and 43 wt % incinerator ash are reported. However, incorporation of ion-exchange resin waste in modified sulfur cement is not recommended due to poor waste form performance. The work presented in this paper will, in part, present data that can be used to assess the acceptability of polyethylene and modified sulfur cement waste forms to meet the requirements of 10 CFR 61. 8 refs., 10 figs., 6 tabs.

Franz, E.M.; Kalb, P.D.; Colombo, P.

1985-01-01

395

Control of Sulfur Dioxide Emissions from Pulverized Coal-Fired Boilers by Dry Removal with Lime and Limestone Sorbants  

E-print Network

pulverized coal-fired boiler equipment. These are: (1) coal cleaning to remove pyritic sulfur, (2) conventional wet, nonregenerable scrubbing with alkaline slurry and solution processes, and (3) dry processes which involve direct introduction of lime...

Schwartz, M. H.

1979-01-01

396

Sulfur: Not a Silent Element Any More!  

SciTech Connect

To understand the many important functions of sulfur, a ubiquitous element in biological systems, in the environment and for industrial applications, detailed analyses are needed. Characterization of the variety of sulfur functional groups in a natural sample, often occurring in a wide range of oxidation states, became possible when the development of dedicated X-ray absorption near-edge structure (XANES) spectroscopy started in the mid-1980s. This tutorial review provides an overview of sulfur XANES spectroscopic investigations into the role of sulfur in all kinds of natural samples, from sediment and oil to marine-archaeological wood and plants.

Jalilehvand, F.

2007-07-09

397

Geochemical Reservoirs and Timing of Sulfur Cycling on Mars  

NASA Astrophysics Data System (ADS)

Sulfate-dominated sedimentary deposits are widespread on the surface of Mars, which contrasts with the rarity of carbonate deposits, and indicates surface waters with chemical features drastically different from those on Earth. While the Earth's surface chemistry and climate are intimately tied to the carbon cycle, it is the sulfur cycle that most strongly influences the Martian geosystems. The presence of sulfate minerals observed from orbit and in-situ via surface exploration within sedimentary rocks and unconsolidated regolith traces a history of post-Noachian aqueous processes mediated by sulfur. These materials likely formed in water-limited aqueous conditions compared to environments indicated by clay minerals and localized carbonates that formed in surface and subsurface settings on early Mars. Constraining the timing of sulfur delivery to the Martian exosphere, as well as volcanogenic H2O is therefore central, as it combines with volcanogenic sulfur to produce acidic fluids and ice. Here, we reassess and review the Martian geochemical reservoirs of sulfur from the innermost core, to the mantle, crust, and surficial sediments. The recognized occurrences and the mineralogical features of sedimentary sulfate deposits are synthesized and summarized. Existing models of formation of sedimentary sulfate are discussed and related to weathering processes and chemical conditions of surface waters. We also review existing models of sulfur content in the Martian mantle and analyze how volcanic activities may have transferred igneous sulfur into the exosphere and evaluate the mass transfers and speciation relationships between volcanic sulfur and sedimentary sulfates. The sedimentary clay-sulfate succession can be reconciled with a continuous volcanic eruption rate throughout the Noachian-Hesperian, but a process occurring around the mid-Noachian must have profoundly changed the composition of volcanic degassing. A hypothetical increase in the oxidation state or in water content of Martian lavas or a decrease in atmospheric pressure is necessary to account for such a change in composition of volcanic gases. This would allow the pre mid-Noachian volcanic gases to be dominated by water and carbon-species but late Noachian and Hesperian volcanic gases to be sulfur-rich and characterized by high SO2 content. Interruption of early dynamo and impact ejection of the atmosphere may have decreased the atmospheric pressure during the early Noachian whereas it remains unclear how the redox state or water content of lavas could have changed. Nevertheless, volcanic emission of SO2 rich gases since the late Noachian can explain many features of Martian sulfate-rich regolith, including the mass of sulfate and the particular chemical features (i.e. acidity) of surface waters accompanying these deposits. How SO2 impacted on Mars's climate, with possible short time scale global warming and long time scale cooling effects, remains controversial. However, the ancient wet and warm era on Mars seems incompatible with elevated atmospheric sulfur dioxide because conditions favorable to volcanic SO2 degassing were most likely not in place at this time.

Gaillard, Fabrice; Michalski, Joseph; Berger, Gilles; McLennan, Scott M.; Scaillet, Bruno

2013-01-01

398

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

399

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

400

Electrochemical properties of sulfur electrode containing nano Al2O3 for lithium\\/sulfur cell  

Microsoft Academic Search

To prevent the dissolution of lithium polysulfides into liquid electrolyte and to promote the lithium\\/sulfur redox reaction, nano-sized Al2O3 particles having large specific surface area were added into sulfur electrode. The effects of nano-sized Al2O3 particles on the electrochemical properties of sulfur electrode for lithium\\/sulfur battery were investigated using CV measurements, charge\\/discharge tests and ionic conductivity measurements of liquid electrolyte.

Y. J. Choi; B. S. Jung; D. J. Lee; J. H. Jeong; K. W. Kim; H. J. Ahn; K. K. Cho; H. B. Gu

2007-01-01

401

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

402

[Investigation on formation mechanism of secologanic acid sulfonates in sulfur-fumigated buds of Lonicera japonica].  

PubMed

To investigate formation mechanism of secologanic acid sulfonates in sulfur-fumigated buds of Lonicera japonica, secologanic acid was enriched and purified from the sun-dried buds of L. japonica by various column chromatography on macroporus resin HPD-100, silica gel and ODS. The stimulation experiments of sulfur-fumigation process were carried out using secologanic acid reacted with SO2 in the aqueous solution. The reaction mechanism could be involved in the esterification or addition reaction. The present investigation provides substantial evidences for interpreting formation pathway of secologanic acid sulfonates in sulfur-fumigated buds of L. japonica. PMID:25095376

Guo, Ai-Li; Gao, Hui-Min; Chen, Liang-Mian; Zhang, Qi-Wei; Wang, Zhi-Min

2014-05-01

403

Sulfur in lunar mare basalts as a function of bulk composition  

NASA Technical Reports Server (NTRS)

Sulfur abundances and metallic iron abundances in 18 Apollo 12 mare basalts were determined. No correlation between sulfur abundance and metallic iron content was detected; metallic iron abundances are not primarily caused by S loss. Sulfur abundances, directly related to the bulk composition of the rocks and especially to the TiO2 content, increase with increasing degrees of fractionation and appear to result from S concentration in the melts during fractionation. Unlike the Apollo 17 melts, the Apollo 12 melts were unsaturated with respect to sulfide. Composition appears to control S content for Apollo 17 basalts, and cumulus processes may cause Fe-FeS enrichment.

Gibson, E. K., Jr.; Brett, R.; Andrawes, F.

1977-01-01

404

Sulfur species in graphene oxide.  

PubMed

The structure of graphene oxide (GO) is of crucial importance for its chemical functionalization. However, the sulfur content present in GO prepared by Hummers' method has only been addressed by a few authors so far. It has been reported that hydrolysis of sulfur species takes place and that stable sulfonic groups are present in graphite oxide. In this manuscript, in contrast to earlier reports, sulfate species are identified that are covalently bound to GO and still present after extensive aqueous work-up. Additionally, we exclude the possibility that sulfonic groups are present in GO as major species after aqueous work up. Our results are based on bulk characterization of graphene oxide by thermogravimetry and subsequent analysis of the decomposition products using mass spectroscopy and infrared spectroscopy. Up to now, the combustion temperature between 200 and 300 °C remained almost unaddressed. In a temperature dependant experiment we reveal two main decomposition steps that differ in temperature and that are closely related to the sulfur species in GO. While the decomposition, between 200 and 300 °C, is related to the degradation of organosulfate, the other one, between 700 and 800 °C, is assigned to the pyrolysis of inorganic sulfate. Furthermore, organosulfate is to some extent responsible for the reactivity of GO. Therefore, the structural model of GO was extended by adding organosulfate in addition to epoxy and hydroxyl groups, which are predominantly covalently bound above and below the carbon skeleton. Furthermore, the identification of organosulfate groups beneath epoxy groups makes new molecular architectures feasible and can be used to explain the properties of GO in various applications. PMID:23780799

Eigler, Siegfried; Dotzer, Christoph; Hof, Ferdinand; Bauer, Walter; Hirsch, Andreas

2013-07-15

405

Effects of ZnO-nanostructure antireflection coatings on sulfurization-free Cu2ZnSnS4 absorber deposited by single-step co-sputtering process  

NASA Astrophysics Data System (ADS)

ZnO nanostructures as anti-reflective coatings were synthesized by using hydrothermal technique for a sulfurization-free Cu2ZnSnS4 absorber prepared by co-sputtering deposition. By controlling the morphology of solution-grown ZnO nanostructures, the average reflectance of the Cu2ZnSnS4 solar cell with branched ZnO nanorods decreased from 7.6% to 1.12%, and the energy conversion efficiency promoted by 10.4% from the initial value of 4.8% to 5.3%. The efficiency improvement was well studied with the effects of the gradually increased refractive index between the air and the top electrode of Cu2ZnSnS4 solar device, due to the presence of the ZnO nanostructure.

Jheng, Bao-Tang; Liu, Po-Tsun; Wang, Min-Chuan; Wu, Meng-Chyi

2013-07-01

406

Characterization of Sulfur Compounds in Coffee Beans by Sulfur K-XANES Spectroscopy  

NASA Astrophysics Data System (ADS)

In this `feasibility study' the influence of roasting on the sulfur speciation in Mexican coffee beans was investigated by sulfur K-XANES Spectroscopy. Spectra of green and slightly roasted beans could be fitted to a linear combination of `standard' reference spectra for biological samples, whereas longer roasting obviously involves formation of additional sulfur compounds in considerable amounts.

Lichtenberg, H.; Prange, A.; Modrow, H.; Hormes, J.

2007-02-01

407

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

408

Massive atmospheric sulfur loading of the AD 1600 Huaynaputina eruption and implications for petrologic sulfur estimates  

E-print Network

Massive atmospheric sulfur loading of the AD 1600 Huaynaputina eruption and implications for petrologic sulfur estimates Fidel Costa1 and Bruno Scaillet Institut des Sciences de la Terre d'Orle´ans, UMR petrological, analytical, and thermodyna- mical data to constrain the sulfur yield of the AD 1600 Huaynaputina

Paris-Sud XI, Université de

409

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

410

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 ...

411

Sulfur distribution in the oil fractions obtained by thermal cracking of Jordanian El-Lajjun oil Shale  

Microsoft Academic Search

The extracted shale oil by the thermal cracking process of the El-Lujjan oil shale showed that the yield of oil was around 12 wt%. The amount of sulfur in this shale oil was found to increase (from 7 to 9.5 wt%) with the increase of the boiling point for different distillate fractions. Sulfur in Jordanian oil shale was found to

Adnan Al-Harahsheh; Awni Y. Al-Otoom; Reyad A. Shawabkeh

2005-01-01

412

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

413

The production and utilization of intermediary elemental sulfur during the oxidation of reduced sulfur compounds by Thiobacillus ferrooxidans  

Microsoft Academic Search

The intermediary production of elemental sulfur during the microbial oxidation of reduced sulfur compounds has frequently been reported. Thiobacillus ferrooxidans, an acidophilic chemolithoautotroph, was found to produce an insoluble sulfur compound, primarily elemental sulfur, during the oxidation of thiosulfate, trithionate, tetrathionate and sulfide. This was confirmed by light and electron microscopy. Sulfur was produced from sulfide by an oxidative step,

W. Hazeu; P. Bos; R. K. Van der Pas; J. G. Kuenen

1988-01-01

414

Advanced Byproduct Recovery: Direct Catalytic Reduction of Sulfur Dioxide to Elemental Sulfur. Sixth quarterly technical progress report, January - March 1997  

SciTech Connect

More than 170 wet scrubber systems applied, to 72,000 MW of U.S., coal-fired, utility boilers are in operation or under construction. In these systems, the sulfur dioxide removed from 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). Due to the abundance and low cost of naturally occurring gypsum, and the costs associated with producing an industrial quality product, less than 7% of these scrubbers are configured to produce usable gypsum (and only 1% of all units actually sell the byproduct). The disposal of solid waste from each of these scrubbers requires a landfill area of approximately 200 to 400 acres. In the U.S., a total of 19 million tons of disposable FGD byproduct are produced, transported and disposed of in landfills annually. The use of regenerable sorbent technologies has the potential to reduce or eliminate solid waste production, transportation and disposal. In a regenerable sorbent system, the sulfur dioxide in the boiler flue gas is removed by the sorbent in an adsorber. The S0{sub 2}s subsequently released, in higher concentration, in a regenerator. All regenerable systems produce an off-gas stream from the regenerator that must be processed further in order to obtain a salable byproduct, such as elemental sulfur, sulfuric acid or liquid S0{sub 2}.

NONE

1997-03-01

415

Advanced Byproduct Recovery: Direct Catalytic Reduction of Sulfur Dioxide to Elemental Sulfur. Fifth quarterly technical progress report, December 1996  

SciTech Connect

More than 170 wet scrubber systems applied, to 72,000 MW of U.S., coal-fired, utility boilers are in operation or under construction. In these systems, the sulfur dioxide removed from 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). Due to the abundance and low cost of naturally occurring gypsum, and the costs associated with producing an industrial quality product, less than 7% of these scrubbers are configured to produce usable gypsum (and only 1% of all units actually sell the byproduct). The disposal of solid waste from each of these scrubbers requires a landfill area of approximately 200 to 400 acres. In the U.S., a total of 19 million tons of disposable FGD byproduct are produced, transported and disposed of in landfills annually. The use of regenerable sorbent technologies has the potential to reduce or eliminate solid waste production, transportation and disposal. In a regenerable sorbent system, the sulfur dioxide in the boiler flue gas is removed by the sorbent in an adsorber. The S0{sub 2}s subsequently released, in higher concentration, in a regenerator. All regenerable systems produce an off-gas stream from the regenerator that must be processed further in order to obtain a salable byproduct, such as elemental sulfur, sulfuric acid or liquid S0{sub 2}.

NONE

1996-12-01

416

Sulfur Species as Redox Partners and Electron Shuttles for Ferrihydrite Reduction by Sulfurospirillum deleyianum  

PubMed Central

Iron(III) (oxyhydr)oxides can represent the dominant microbial electron acceptors under anoxic conditions in many aquatic environments, which makes understanding the mechanisms and processes regulating their dissolution and transformation particularly important. In a previous laboratory-based study, it has been shown that 0.05 mM thiosulfate can reduce 6 mM ferrihydrite indirectly via enzymatic reduction of thiosulfate to sulfide by the sulfur-reducing bacterium Sulfurospirillum deleyianum, followed by abiotic reduction of ferrihydrite coupled to reoxidation of sulfide. Thiosulfate, elemental sulfur, and polysulfides were proposed as reoxidized sulfur species functioning as electron shuttles. However, the exact electron transfer pathway remained unknown. Here, we present a detailed analysis of the sulfur species involved. Apart from thiosulfate, substoichiometric amounts of sulfite, tetrathionate, sulfide, or polysulfides also initiated ferrihydrite reduction. The portion of thiosulfate produced during abiotic ferrihydrite-dependent reoxidation of sulfide was about 10% of the total sulfur at maximum. The main abiotic oxidation product was elemental sulfur attached to the iron mineral surface, which indicates that direct contact between microorganisms and ferrihydrite is necessary to maintain the iron reduction process. Polysulfides were not detected in the liquid phase. Minor amounts were found associated either with microorganisms or the mineral phase. The abiotic oxidation of sulfide in the reaction with ferrihydrite was identified as rate determining. Cysteine, added as a sulfur source and a reducing agent, also led to abiotic ferrihydrite reduction and therefore should be eliminated when sulfur redox reactions are investigated. Overall, we could demonstrate the large impact of intermediate sulfur species on biogeochemical iron transformations. PMID:24632263

Lohmayer, Regina; Kappler, Andreas; Losekann-Behrens, Tina

2014-01-01

417

Toward Understanding the Effect of Nuclear Waste Glass Composition of Sulfur Solubility  

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) depending on the composition of the melter feed and processing conditions. If the amount of sulfur exceeds the melt tolerance level, a molten salt will accumulate, which may upset melter operations and potentially shorten the useful life of the melter. At the Hanford site, relatively conservative limits have been placed on sulfur loading in melter feed, which in turn significantly increases the amount of glass that will be produced. 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 252 simulated Hanford low-activity waste (LAW) glass compositions. This model represents the data well, accounting for over 85% of the variation in data, and was well validated. The model was also found to accurately predict the tolerance for sulfur in melter feed for 13 scaled melter tests of simulated LAW glasses. The model can be used to help estimate glass volumes and make informed decisions on process options. The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that most increase sulfur solubility are Li2O > V2O5> CaO ? P2O5 > Na2O ? B2O3 > K2O. The components that most decrease sulfur solubility are Cl > Cr2O3 > Al2O3 > ZrO2 ? SnO2 > Others ? SiO2. The order of component effects is similar to previous literature data, in most cases.

Vienna, John D.; Kim, Dong-Sang; Muller, I. S.; Kruger, Albert A.; Piepel, Gregory F.

2014-02-13

418

Isotopic inferences of ancient biochemistries - Carbon, sulfur, hydrogen, and nitrogen  

NASA Technical Reports Server (NTRS)

In processes of biological incorporation and subsequent biochemical processing sizable isotope effects occur as a result of both thermodynamic and kinetic fractionations which take place during metabolic and biosynthetic reactions. In this chapter a review is provided of earlier work and recent studies on isotope fractionations in the biogeochemical cycles of carbon, sulfur, hydrogen, and nitrogen. Attention is given to the biochemistry of carbon isotope fractionation, carbon isotope fractionation in extant plants and microorganisms, isotope fractionation in the terrestrial carbon cycle, the effects of diagenesis and metamorphism on the isotopic composition of sedimentary carbon, the isotopic composition of sedimentary carbon through time, implications of the sedimentary carbon isotope record, the biochemistry of sulfur isotope fractionation, pathways of the biogeochemical cycle of nitrogen, and the D/H ratio in naturally occurring materials.

Schidlowski, M.; Hayes, J. M.; Kaplan, I. R.

1983-01-01

419

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

420

40 CFR 52.1030 - Control strategy: Sulfur oxides.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Control strategy: Sulfur oxides. 52.1030 Section 52... § 52.1030 Control strategy: Sulfur oxides. (a) The revision to Regulation 100.6 (Chapter 106) “Low Sulfur Fuel Regulation” for the...

2013-07-01

421

40 CFR 52.1117 - Control strategy: Sulfur oxides.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Control strategy: Sulfur oxides. 52.1117 Section 52.1117...Maryland § 52.1117 Control strategy: Sulfur oxides. (a) [Reserved] ...attainment and maintenance of the national sulfur dioxide standards. [40 FR...

2012-07-01

422

40 CFR 52.231 - Regulations: Sulfur oxides.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Regulations: Sulfur oxides. 52.231 Section 52.231...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved...National Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County...

2011-07-01

423

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...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved...National Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County...

2013-07-01

424

40 CFR 52.1030 - Control strategy: Sulfur oxides.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Control strategy: Sulfur oxides. 52.1030 Section 52... § 52.1030 Control strategy: Sulfur oxides. (a) The revision to Regulation 100.6 (Chapter 106) “Low Sulfur Fuel Regulation” for the...

2011-07-01

425

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...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved...National Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County...

2010-07-01

426

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...California § 52.231 Regulations: Sulfur oxides. (a) [Reserved...National Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County...

2012-07-01

427

Transport and equilibrium in molecular plasmas: the sulfur lamp  

E-print Network

Transport and equilibrium in molecular plasmas: the sulfur lamp PROEFSCHRIFT ter verkrijging van de William Transport and equilibrium in molecular plasmas: the sulfur lamp / by Colin William Johnston. : plasma / zwavel lamp / moleculen / transporteigenschappen Subject headings : plasma / sulfur lamp

Eindhoven, Technische Universiteit

428

40 CFR 52.795 - Control strategy: Sulfur dioxide.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Control strategy: Sulfur dioxide. 52.795 Section 52.795 Protection...52.795 Control strategy: Sulfur dioxide. (a) Revised APC-13 (December...Pollution Control regulations (sulfur dioxide emission limitation) is...

2011-07-01

429

40 CFR 52.795 - Control strategy: Sulfur dioxide.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Control strategy: Sulfur dioxide. 52.795 Section 52.795 Protection...52.795 Control strategy: Sulfur dioxide. (a) Revised APC-13 (December...Pollution Control regulations (sulfur dioxide emission limitation) is...

2013-07-01

430

46 CFR 151.50-84 - Sulfur dioxide.  

...2014-10-01 2014-10-01 false Sulfur dioxide. 151.50-84 Section 151.50-84 Shipping... Special Requirements § 151.50-84 Sulfur dioxide. (a) Sulfur dioxide that is transported under the provisions of...

2014-10-01

431