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1

Elemental sulfur recovery process  

DOEpatents

An improved catalytic reduction process for the direct recovery of elemental sulfur from various SO[sub 2]-containing industrial gas streams. The catalytic process provides combined high activity and selectivity for the reduction of SO[sub 2] to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over certain catalyst formulations based on cerium oxide. The process is a single-stage, catalytic sulfur recovery process in conjunction with regenerators, such as those used in dry, regenerative flue gas desulfurization or other processes, involving direct reduction of the SO[sub 2] in the regenerator off gas stream to elemental sulfur in the presence of a catalyst. 4 figures.

Flytzani-Stephanopoulos, M.; Zhicheng Hu.

1993-09-07

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  

SciTech Connect

A process is described for removing sulfur dioxide from a gas stream with a buffered, aqueous thiosulfate/polythionate solution which comprises: (a) introducing sulfur dioxide-containing gas, recovered hydrogen sulfide, and a buffered, aqueous, lean thiosulfate/polythionate solution to an SO/sub 2/-gas/liquid contacting zone; (b) recovering cleaned gas and a buffered, aqueous, enriched thiosulfate/polythionate solution from the SO/sub 2/-gas/liquid contacting zone; (c) introducing the recovered, enriched solution to a regeneration zone; (d) introducing externally supplied hydrogen sulfide to the regeneration zone to react a portion of the recovered, enriched solution therein to form a slurry of elemental sulfur in a buffered, aqueous, lean thiosulfate/polythionate solution; (e) recovering unreacted excess hydrogen sulfide from the regeneration zone for use in step (a); and (f) withdrawing the slurry from the regeneration zone, separating elemental sulfur from the slurry, and recovering the buffered, aqueous, lean thiosulfate/polythionate solution for use in step (a).

Sliger, A.G.; O'Donnell, J.J.; Northup, A.H. Jr.

1987-01-06

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

Process for removing sulfur and sulfur compounds from the effluent of industrial processes  

Microsoft Academic Search

Sulfur dioxide in the stack gas from an industrial process is converted to elemental sulfur in a claus reactor at low temperature to produce sulfur fume. The sulfur is condensed by direct heat transfer with a continuously flowing countercurrent recirculating catalyst and a substantially sulfur dioxide-free gas is discharged. Catalyst and condensed sulfur are fed into the top of a

Sims

1981-01-01

6

Process for removing sulfur from sulfur-containing gases  

SciTech Connect

This patent describes a process for reducing the level of sulfur in a sulfur dioxide-containing gas. It comprises: preparing an aqueous slurry comprising a calcium alkali together with a calcium-reactive silica or alumina which are present in amounts sufficient to allow for the formation of a sulfur dioxide-absorbing component which includes a calcium silicate or calcium aluminate; heating the slurry to a temperature between about 40{degrees} and about 200{degrees} C. to facilitate in the formation of the sulfur dioxide-absorbing component; contacting the gas with the slurry in a manner sufficient to allow for the absorption of sulfur dioxide by the absorbing component; and separating the absorbing component in the form of spent solids from the gas.

Rochelle, G.T.; Jozewicz, W.

1990-06-05

7

Process for removing sulfur from sulfur-containing gases  

SciTech Connect

This patent describes a process for reducing the level of sulfur dioxide in a sulfur dioxide- containing gas. It comprises preparing an aqueous slurry comprising a calcium alkali together with a calcium-reactive silica or alumina, the calcium alkali and calcium-reactive silica or alumina being introduced into the slurry in a form consisting essentially of a high calcium fly ash, which are present in amounts sufficient to allow for the formation of a sulfur dioxide-absorbing component which includes a calcium silicate or calcium aluminate; heating the slurry to a temperature between about 50{degrees} and 200{degrees} C. for between about 0.1 and about 24 hours to facilitate in the formation of the sulfur dioxide-absorbing component; contacting the gas with the slurry in a manner sufficient to allow for the absorption of sulfur dioxide by the absorbing component; and separating the absorbing component in the form of spent solids from the gas.

Rochelle, G.T.; Chang, J.C.S.

1991-09-10

8

Process for removing sulfur from sulfur-containing gases  

SciTech Connect

This patent describes a process for reducing the level of sulfur dioxide in a sulfur dioxide- containing gas. It comprises preparing an aqueous slurry comprising a calcium alkali together with a calcium-reactive silica or alumina which are present in amounts sufficient to allow for the formation of a sulfur dioxide-absorbing component which includes a calcium silicate or calcium aluminate; heating the slurry to a temperature between about 120{degrees} and 180{degrees} C. to facilitate in the formation of the sulfur dioxide-absorbing component; contacting the gas with the slurry in a manner sufficient to allow for the absorption of sulfur dioxide by the absorbing component; and separating the absorbing component in the form of spent solids from the gas.

Jozewicz, W.; Chang, J.C.S.; Sedman, C.B.; Brna, T.G.; Rochelle, G.T.

1991-09-10

9

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

10

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

11

Process for removing sulfur from coal  

DOEpatents

A process 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, Tetsuo (Ames, IA) [Ames, IA; Squires, Thomas G. (Gilbert, IA) [Gilbert, IA; Venier, Clifford G. (Ames, IA) [Ames, IA

1985-02-05

12

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 HS (Claus plant feed), Claus plant tail gas, SO (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

13

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

14

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

15

Hybrid Sulfur Thermochemical Process Development Annual Report  

Microsoft Academic Search

The Hybrid Sulfur (HyS) Thermochemical Process is a means of producing hydrogen via water-splitting through a combination of chemical reactions and electrochemistry. Energy is supplied to the system as high temperature heat (approximately 900 C) and electricity. Advanced nuclear reactors (Generation IV) or central solar receivers can be the source of the primary energy. Large-scale hydrogen production based on this

William A. Summers; Melvin R. Buckner

2005-01-01

16

Assessment of Sulfur Removal Processes for Advanced Fuel Cell Systems.  

National Technical Information Service (NTIS)

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 remov...

G. A. Lorton

1980-01-01

17

Process for combusting solid sulfur-containing material  

Microsoft Academic Search

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

J. S. Yoo; J. A. Jaecker

1988-01-01

18

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

19

Comparison of the UCB sulfur recovery process with conventional sulfur recovery technology for treating recycle gas from a crude oil residuum hydrotreater. [UCBSRP sulfur recovery process  

Microsoft Academic Search

The University of California, Berkeley, Sulfur Recovery Process (UCBSRP) is being developed as an alternative to conventional sulfur recovery technology for removing hydrogen sulfide from gas streams and converting it to elemental sulfur. In the UCBSRP the hydrogen sulfide is absorbed by a physical solvent and the resulting solution of HS is mixed with a stoichiometrically equivalent amount of slulfur

S. Lynn; D. W. Neumann; S. F. Sciamanna; F. H. Vorhis

1986-01-01

20

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

21

Process for producing sulfur from sour gas  

Microsoft Academic Search

A method is described for the recovery of free sulfur from sour gas streams by the catalytic conversion of hydrogen sulfide, under conditions such that unreacted sulfur compounds discharged to the atmosphere are held to a minimum. This is accomplished by taking advantage of the increased recovery obtained by the use of low temperature reactors. In a 3-reactor plant, the

1973-01-01

22

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

DOEpatents

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

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

1991-01-01

23

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

24

An early application of the Sulfur Cycle Hydrogen Production Process  

NASA Astrophysics Data System (ADS)

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

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

25

Atmospheric Emissions from Sulfuric Acid Manufacturing Processes.  

National Technical Information Service (NTIS)

The report has been prepared to provide reliable information on atmospheric emissions from sulfuric acid manufacturing plants and on method and equipment normally employed to limit these emissions to satisfactory levels. Background information is included...

S. T. Cuffe C. M. Dean

1965-01-01

26

Process for Producing Sulfurous Acid Treated Alumina.  

National Technical Information Service (NTIS)

The activated alumina is effective for bleaching refined cottonseed oil. It is prepared by soaking ground activated alumina with an aqueous solution of sulfurous acid until a specific saturation is reached. The alumina is then removed from the solution an...

W. A. Pons J. C. Kuck V. L. Frampton

1964-01-01

27

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

28

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

Microsoft Academic Search

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 HS in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day.

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

2001-01-01

29

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

Microsoft Academic Search

This first quarter report of 2002 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 HS in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day.

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

2002-01-01

30

Membrane separation processes for the benefit of the sulfuriodine and hybrid sulfur thermochemical cycles  

Microsoft Academic Search

Thermochemical cycles have been proposed as processes for the manufacture of hydrogen from water in which the only other effluent is oxygen. In this paper, membrane-based technologies are described that have the promise of enabling the further development of thermochemical cycle processes. Membranes have been studied for the concentration of hydriodic acid (HI) and sulfuric acid using pervaporation. In this

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

2009-01-01

31

Sulfur  

Microsoft Academic Search

Sulfur, an element in wide industrial use, currently is mined or recovered in the U.S. from elemental sulfur deposits associated with evaporites, from sulfur-bearing petroleum and natural gas, and from sulfide ores. The element also occurs as a constituent in bedded gypsum and anhydrite, coal, tar sands, and oil shale, as well as in volcanic deposits, none of which is

Bodenlos

1973-01-01

32

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

33

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This first quarter report of 2004 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 while avoiding methane oxidation and fouling due to coking from other hydrocarbon contaminants. 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 site in west Texas.

Dennis Dalrymple

2004-04-01

34

Process for treating high sulfur caking coals to inactivate the sulfur and eliminate caking tendencies thereof  

SciTech Connect

A one or two-step process of treating high-sulfur caking coals for desulfurization, elimination of caking tendencies and incorporation of gasification catalyst thereon prior to steam-or hydrogasification thereof, or its use as a boiler fuel. In the one step process the coal is subjected to an aqueous lime/O/sub 2/ (or air) treatment under controlled conditions of time, temperature and pressure to accomplish the foregoing, whereas in the two-step process the coal is first treated with oxygen or air in dilute alkaline slurry at elevated temperature and pressure to remove the sulfur and then treated with a lime slurry, under controlled temperature conditions to incorporate the catalytic inducing lime.

Espenschied, W.F.

1985-06-11

35

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This first 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

2003-04-01

36

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

37

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This fourth quarter report of 2002 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of 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.

Joe Lundeen; Girish Srinivas; David W. DeBerry

2003-01-01

38

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This second quarter report of 2002 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of 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. This report describes testing using the laboratory apparatus but operated at the pilot plant using the actual pilot plant gas, which contains far more contaminants than can be simulated in the laboratory. The results are very encouraging, with stable and efficient operation being obtained for a prolonged period of time.

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

2002-07-01

39

QUATAM PROCESSNEW SULFUR-FREE DELIGNIFICATION  

Microsoft Academic Search

An essentially new alkaline chemical pulping processthe Quatam processhas been introduced using an organic base for producing cellulose fibers from wood and annual plants. Solutions of quaternary ammonium compounds, preferably tetramethylammonium hydroxide (TMAH), serve as pulping liquors. The process produces high quality pulp with low kappa number, high brightness and good viscositywithout using sulfur-containing compounds. The process is suitable for

Ildiko Tanczos; Harald Schmidt

2002-01-01

40

Process and apparatus for recovery of sulfur from ammonia containing acid gas streams  

Microsoft Academic Search

This patent describes a Claus process for the recovery of sulfur, the steps comprising: passing a first stream containing hydrogen sulfide, sulfur dioxide, and ammonia through a low temperature Claus catalytic conversion zone and depositing elemental sulfur and ammonium compounds on catalyst therein; deriving a regeneration stream from the Claus process and regenerating the resulting laden catalyst therewith vaporizing sulfur

1987-01-01

41

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

Microsoft Academic Search

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

2010-01-01

42

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

SciTech Connect

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

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

2009-05-01

43

Optimal process pattern for simultaneous sulfur, nitrogen and carbon removal.  

PubMed

Denitrifying sulfide removal (DSR) process incorporates interactions between autotrophic and heterotrophic denitrifiers and reveals difficulty to achieve high removal rate of nitrogen and sulfur in practice. We compared the DSR performance of an expanded granular sludge bed (EGSB) reactor and an upflow anaerobic sludge blanket (UASB) reactor, both fed with wastewaters comprising sulfide, nitrate and acetate. The EGSB reactor can sustain at higher loading rates than UASB reactor, probably owing to the less elemental sulfur production rate for the latter in operation. PMID:19237779

Chen, Chuan; Wang, Aijie; Ren, Nanqi; Deng, Xuliang; Lee, Duu-Jong

2009-01-01

44

Process for eliminating diluted sulfur oxides in combustion exhaust gases  

Microsoft Academic Search

A process is disclosed for eliminating sulfur oxides from combustion exhaust gases, comprising the steps of dividing the combustion exhaust gases into a first stream and a second stream, and passing the first stream through a first activated carbon bed which was previously washed with water, thereby drying the activated carbon, cooling the first stream, and removing a substantial portion

S. Hori; T. Inoue; S. Yamamoto; K. Tatara; M. Kitagawa; M. Watanabe; Y. Okada; N. Negishi

1978-01-01

45

Nuclear Hydrogen Production Based on the Hybrid Sulfur Thermochemical Process  

SciTech Connect

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

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

2006-07-01

46

Process for Treating by Products of Lithium/Sulfur Hexafluoride.  

National Technical Information Service (NTIS)

A process is provided for treating the solid reaction by-products of lithium and sulfur hexafluoride. Lithium in the by-product solid waste is converted to lithium hydroxide. Lithium sulfide in the by-product is converted to lithium hydroxide. Lithium sul...

L. E. Lema

1995-01-01

47

Process for removing sulfur dioxide from flue gases  

Microsoft Academic Search

This patent describes an improvement in a dry process for the removal of sulfur dioxide from flue gases by the addition thereto of hydrated lime containing sugar in a coal combustion unit, wherein the flue gases result from the combustion of a coal in a combustion chamber, and the flue gases are treated in an electrostatic precipitator prior to discharge

M. W. Jr

1989-01-01

48

Testing of a sulfur tolerant direct methanation process  

Microsoft Academic Search

A new sulfur tolerant catalyst for methane formation from carbon monoxide and hydrogen has been tested at Haldor Topsoe's laboratory and at Mountain Fuel Resources' entrained coal gasification Process Development Unit. The catalyst also effectively catalyzes the shift reaction, which permits direct methanation of raw coal gas. In contrast to nickel-based methanation catalyst, it is not necessary to add steam

A. Skov; K. Pedersen; C. Chen; R. L. Coates

1986-01-01

49

Catalyst and process technologies for ultra low sulfur diesel  

Microsoft Academic Search

The production of clean diesel by hydrotreating and deep hydrodesulfurization (HDS) has attracted increased attention recently due to the introduction of new environmental legislation regarding fuel specifications. In order to meet the specifications there is a need to modify and improve existing reactors and processes and to introduce more active and selective catalysts. The removal of sterically hindered sulfur-containing molecules

Kim G Knudsen; Barry H Cooper; Henrik Topse

1999-01-01

50

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

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

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

2001-08-01

51

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

This first quarter report of 2002 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{sup SM} (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. In a previous reporting period tests were done to determine the effect of hydrocarbons such as n-hexane on catalyst performance with and without H{sub 2}S present. The experiments showed that hexane oxidation is suppressed when H{sub 2}S is present. Hexane represents the most reactive of the C1 to C6 series of alkanes. Since hexane exhibits low reactivity under H{sub 2}S oxidation conditions, and more importantly, does not change the SO{sub 2} selectivity, we can conclude that the C1-C6 hydrocarbons should not significantly interfere with the oxidation of H{sub 2}S into SO{sub 2}. During this quarter the effect of aromatic compounds were also found to have no effect on catalyst performance. This report gives the results of testing using contaminants from the pilot plant site.

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

2002-04-01

52

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

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

Dennis Dalrymple

2004-06-01

53

General Atomic sulfur-iodine thermochemical water-splitting process  

Microsoft Academic Search

Thermochemical water-splitting has the potential to provide an energy-efficient, low-cost process for the production of hydrogen utilizing a renewable energy supply in conjunction with nonfossil resources. The General Atomic Company (GA) sulfur-iodine cycle which has been under investigation at GA since 1974 is compatible with the heat characteristics projected for three of the major energy sources of the future. These

Besenbruch

1982-01-01

54

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

55

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

56

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

SciTech Connect

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

57

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

Microsoft Academic Search

The sulfuric acid step was identified as the critical part of the thermochemical cycle in dictating the thermal demands and temperature requirements of the heat source. The general atomic sulfur-iodine cycle was coupled to a tandem mirror. The sulfuric acid decomposition process step was focused on specifically since this step can use the high efficiency electrical power of the direct

T. R. Galloway

1981-01-01

58

Wet scrubber process for removing total reduced sulfur compounds from industrial gases  

Microsoft Academic Search

This patent describes a process for the removal of total reduced sulfur compounds and recovery of non-magnetic entrained particulates from an industrial gas. It comprises: scrubbing the industrial gas with an aqueous absorbent slurry containing activated manganese dioxide absorbent particles in a reaction zone to effect oxidation of the total reduced sulfur compounds and recovery of total reduced sulfur compound

Iannicelli

1990-01-01

59

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

60

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

61

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

62

Shale sulfur and iron chemistry in the Kentort II process  

Microsoft Academic Search

Eastern US shales are high in sulfur in comparison to the Green River Formation Shales of Colorado and Utah. The most economically attractive Mississippian and Devonian Black Shales range from 2 to 4% total sulfur versus the 0.4 to 0.7% reported for the Mahogany Zone Green River Formation. Sulfur in eastern US shales is primarily associated with pyrite (FeS) with

A. M. Rubel; S. D. Carter; T. L. Robl

1989-01-01

63

Process for the hydrodesulfurization of natural gas containing organic sulfur compounds and oxygen  

Microsoft Academic Search

Process is claimed for hydrodesulfurizing a gas comprising together methane, at least one organic sulfur compound and oxygen, characterized by the step of passing a mixture of said gas with a hydrogen containing gas on a palladium catalyst at a temperature of 300° to 450° C. The gas usually comprises at least 2 mg\\/Nm³ of sulfur as organic sulfur and

A. Deschamps; J. Cosyns; J. F. Le Page

1984-01-01

64

Process for preparing a sulfur dioxide containing gas stream for reaction with coal  

SciTech Connect

A process is described for preparing a gas stream containing sulfur dioxide and water for reaction with coal to convert the sulfur dioxide to gaseous elemental sulfur. Water is initially removed from the gas stream to increase the percentage of sulfur dioxide in the stream after which the gas stream is passed through the flame of a burner to add combustion gases to the gas stream. Steam is then mixed with the gas stream to increase the percentage of water in the gas stream before it is reacted with the coal.

Raskin, N.R.

1984-10-16

65

Process for removing sulfur dioxide from flue gases  

SciTech Connect

This patent describes an improvement in a dry process for the removal of sulfur dioxide from flue gases by the addition thereto of hydrated lime containing sugar in a coal combustion unit, wherein the flue gases result from the combustion of a coal in a combustion chamber, and the flue gases are treated in an electrostatic precipitator prior to discharge to the atmosphere the improvement comprising: passing the flue gases, after the addition of the hydrated lime is of fine particles of a specific surface of 7 to 25 square meters per gram, through a conduit towards the electrostatic precipitator; and adding an aqueous media to the flue gases in the conduit in an amount to increase the water content of the flue gases and cool the same by evaporative cooling to a temperature no lower than 20{sup 0}F. about the dew point of the gas, so as to avoid forming water droplets in the gas, so as to prevent condensation of water therefrom.

Robinson, M.W. Jr.

1989-08-29

66

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...

67

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

PubMed

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

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

2004-07-01

68

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

NASA Astrophysics Data System (ADS)

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

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

69

EQUILIBRIUM PARTIAL PRESSURE OF SULFUR DIOXIDE IN ALKALINE SCRUBBING PROCESSES  

EPA Science Inventory

The report gives results of IERL-RTP in-house studies in which equilibrium partial pressure of SO2 was measured as a function of pH, temperature, and concentration of sulfur (IV) on various scrubber liquors. These studies were done for potassium-, sodium-, and citrate-based scrub...

70

Sulfur tolerant molten carbonate fuel cell anode and process  

DOEpatents

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

Remick, Robert J. (Naperville, IL)

1990-01-01

71

Process for removing sulfur from a hydrocarbon feedstream using a sulfur sorbent with alkali metal components or alkaline earth metal components  

SciTech Connect

This patent describes a process for removing sulfur and sulfur compounds from a naphtha feed. It comprises: contacting a naphtha feed with a platinum on alumina catalyst in the presence of added hydrogen so as to convert thiophenic or organic sulfur compounds to hydrogen sulfide under mild reforming conditions wherein the temperature is no greater than about 500[degrees]C and the pressure is no greater than about 250 psig; and contacting the naphtha with a sulfur sorbent which comprises a Group I-A or Group II-A metal supported on a porous refractory inorganic oxide support to remove hydrogen sulfide from the naphtha feed.

Field, L.A.

1991-10-22

72

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

Microsoft Academic Search

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

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

1988-01-01

73

Process for the removal of hydrogen sulfide from gaseous streams by catalytic oxidation of hydrogen sulfide to sulfur while inhibiting the formation of sulfur oxides  

Microsoft Academic Search

A process is provided for removing hydrogen sulfide and alkyl mercaptans from gaseous streams. The hydrogen sulfide is oxidized catalytically to sulfur, substantially without formation of sulfur oxides, in the presence of a metal chelate catalyst solution and a soluble alkali metal or alkaline earth metal or ammonium or amine salt of an acid having a pK within the range

Meuly

1977-01-01

74

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

Microsoft Academic Search

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

Raul E. Ayala; Eli Gal

1995-01-01

75

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

76

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.

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

2011-01-01

77

Hydrogen production by the GA sulfur-iodine process - A progress report  

NASA Astrophysics Data System (ADS)

Progress made over a two-year period on a sulfur-iodine thermochemical water-splitting cycle is summarized. The major accomplishments are listed, among which are significant improvements in the chemistry of the process and the development of a conceptual, preliminary flow sheet for a sulfur-iodine cycle driven by solar energy. The results of the work carried out thus far are considered to demonstrate that thermochemical water splitting by the sulfur-iodine cycle is a feasible process and that thermal efficiencies in the range of 50% are attainable. The four areas into which the total process development has been divided - basic chemical investigations, material investigations, process engineering studies, and bench-scale testing - are discussed. It is concluded that the process will be shown to be a viable, economic alternative for hydrogen production.

Besenbruch, G. E.; McCorkel, K. H.; Norman, J. H.; Okeefe, D. R.; Schuster, J. R.; Yoshimoto, M.

78

Sulfur starvation and chromium tolerance in Scenedesmus acutus: a possible link between metal tolerance and the regulation of sulfur uptake/assimilation processes.  

PubMed

In a laboratory-selected Cr-tolerant strain of the unicellular green alga Scenedesmus acutus, the capacity to synthesize higher amounts of cysteine (Cys) and reduced glutathione (GSH) than the wild-type was demonstrated to underlie tolerance to Cd and Cr(VI). In photosynthetic organisms sulfate constitutes the main sulfur source for the biosynthesis of GSH and its precursor Cys, hence it was hypothesized that the sensitivity of the two strains to Cr(VI) could be modified after culturing in sulfate-deprived medium. Both strains were grown in the presence of different concentrations or in the absence of sulfate (sulfur-starved) and then assayed for Cr(VI) tolerance in standard medium. Unstarved, sulfur-starved and sulfur-replete cells (cells maintained in standard medium after S-starvation) were analysed for Cys, GSH and sulfur content. Sulfur-starved cells showed a greater tolerance to Cr(VI) than unstarved ones. The increased tolerance was ascribable to a transient physiological change and can be considered as specifically due to sulfur deprivation, since it was lost after a 3-day culture in standard medium and was not exhibited by nitrogen-starved cells. The comparison between Cys, GSH and sulfur content in sulfur-starved and sulfur-replete cells of the two strains suggests that the higher tolerance to Cr(VI) after S-starvation could depend on the up-regulation of sulfate uptake mechanisms, and that the primary reason for the higher tolerance to chromium in the selected strain could be due to greater sensitivity to the decrease in negative intracellular end-products (free Cys and GSH) leading to an earlier up-regulation of sulfate assimilation processes. PMID:17727973

Gorbi, Gessica; Zanni, Corrado; Corradi, Maria Grazia

2007-10-30

79

Hydrogen production by the GA sulfur-iodine process: a progress report  

Microsoft Academic Search

A summary of the progress of the overall total development effort of the General Atomic (GA) sulfur-iodine thermochemical water-splitting cycle over the last two years is reported. The major accomplishments have been the following: (1) Significant improvements in the chemistry of the process. (2) Development, review, and revision of an engineering flowsheet, resulting in a thermal process efficiency of 47%.

G. E. Besenbruch; K. H. McCorkle; J. H. Norman; D. R. OKeefe; J. R. Schuster; M. Yoshimoto

1980-01-01

80

Catalytic process for removing SO from sulfuric acid plant off gases  

Microsoft Academic Search

The invention is directed to an integrated process for reducing the SO content of sulfuric acid plant off gases by (1) passing the SO-containing feed gas to the process over a specially defined multistage oxidation catalyst to convert SO to SO, (2) absorbing the SO in water to form HSO and (3) scrubbing the off gases with aqueous hydrogen peroxide

1976-01-01

81

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

82

Sulfur oxides control technology series: Flue-gas desulfurization. Spray dryer process. Summary report  

SciTech Connect

The report describes the 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). The hot flue gas dries the droplets to form a dry waste product, while the absorbent reacts with sulfur dioxide in the flue gas. Dry waste solids are collected in a fabric filter (baghouse) or electrostatic precipitator (ESP) and are typically disposed of by landfill. Descriptions of the process as well as its advantages and costs are included in the report.

Not Available

1982-01-01

83

Novel cellulose derivative, process for preparing the same and sulfur dioxide gas permselective membrane comprising the same  

SciTech Connect

This patent relates to a novel cellulose derivative and a sulfur dioxide gas permselective membrane comprising the same, and particularly to hydrocarbylsulfinylethyl cellulose, a process for preparing the same and the sulfur dioxide gas permselective membrane comprising the same. An object of the present invention is to provide hydrocarbylsulfinylethyl cellulose which is a novel cellulose derivative and useful as a material for the sulfur dioxide gas permselective membrane and a process for preparing the same. Another object of the present invention is to supply a novel sulfur dioxide gas permselective membrane having an excellent sulfur dioxide gas permselectivity. The present invention provides hydrocarbylsulfinylethyl cellulose. The novel hydrocarbylsulfinylethyl cellulose of the present invention indicates markedly high sulfur dioxide gas permselectivity compared with the conventional cellulose derivatives, for example, cellulose acetate, ethyl cellulose, etc. Accordingly, the sulfur dioxide gas permselective membrane of the present invention can be utilized for separation, purification of sulfur dioxide gas from a gas mixture such as air or for concentration of sulfur dioxide gas in a gas mixture, and is highly practical in industrial use. More specifically, the sulfur dioxide gas permselective membrane is useful for, for example, removal of harmful sulfur dioxide gas from discharged gases from the viewpoint of environmental protection and purification of starting gases for synthesis, etc. from the viewpoint of industrial production. Further, the hydrocarbylsulfinylethyl cellulose of the present invention is useful for a thickening agent, binder, protective colloidal agent, etc.

Imai, K.; Shiomi, T.; Tezuka, Y.

1987-09-15

84

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

85

Migration of sulfur between organic and inorganic phases during hydrodesulfurization processes  

SciTech Connect

In the course of investigation of the non-isothermal hydrodesulfurization of model organic sulfur compounds in a coal-like environment with and without troilite, it was found that some of the non-thiophenic sulfur from the organic compounds was absorbed by troilite. This observation suggested that during hydrodesulfurization the organic sulfur had migrated to the inorganic phase. As the temperature was raised, more H{sub 2}S evolved from the sample with troilite, suggesting reevolution by pyrrhotite to trolite conversion. The purpose of this study was to use isotopic labeling to determine the mechanism of incorporation of sulfur into troilite. One possibility, as suggested by the formation of pyrrhotite confirmed by Moessbauer spectroscopy, that the H{sub 2}S produced from the organic compound was transferred to the inorganic phase, and then as the temperature was raised, H{sub 2}S evolution occurred from the troilite. Another possibility was that a direct reaction between the troilite and the organic compound took place, forming an intermediate followed by H{sub 2}S evolution from this intermediate as the temperature was raised. The fate and H{sub 2}S evolution profile from the labeling of the mobile organic sulfur group has been studied in an effort to distinguish possible mechanisms and demonstrate the role of troilite in this process.

Dunkerton, L.V.; Hackley, K.C.; Phillips, J.B.; Mitra, S.; Mehrotra, S.; Nigam, A. (Southern Illinois Univ., Carbondale (USA))

1988-01-01

86

SUMMARY REPORT: SULFUR OXIDES CONTROL TECHNOLOGY SERIES: FLUE GAS DESULFURIZATION - DUAL ALKALI PROCESS  

EPA Science Inventory

Describes dual alkali (or double alkali) flue gas desulfurization (FGD) which is a throwaway process in which sulfur dioxide (SO2) is removed from the flue gas by a soluble sodium-based scrubbing liquor. he collected SO2 is precipitated as calcium sulfite (CaSO3), calcium sulfate...

87

DEVELOPMENT OF THE WESTVACO ACTIVATED CARBON PROCESS FOR SOX RECOVERY AS ELEMENTAL SULFUR. VOLUME I  

EPA Science Inventory

The report gives results of a demonstration (in a 20,000-cfh integral pilot plant) of an all-dry, fluidized-bed process, using activated carbon for recovering SO2 as elemental sulfur. Granular carbon was recycled continuously more than 20 times between contact with flue gas from ...

88

DEVELOPMENT OF THE WESTVACO ACTIVATED CARBON PROCESS FOR SOX RECOVERY AS ELEMENTAL SULFUR. VOLUME II. APPENDIX  

EPA Science Inventory

The report gives results of a demonstration (in a 20,000-cfh integral pilot plant) of an all-dry, fluidized-bed process, using activated carbon for recovering SO2 as elemental sulfur. Granular carbon was recycled continuously more than 20 times between contact with flue gas from ...

89

Finishing process for the removal of sulfur compounds from a gas steam  

Microsoft Academic Search

The invention relates to a finishing process for the removal of low level concentrations of mercaptans, sulfides and disulfides from a gas stream, especially a natural gas stream. The sulfur compounds are washed from the gas stream with a solution containing hydrogen peroxide, sodium carbonate or sodium hydroxide, and ammonia or an amine.

J. J. Tazuma; K. J. Frech

1984-01-01

90

Process for recovery of oxides of sulfur from combustion waste gas  

Microsoft Academic Search

A process for the recovery of oxides of sulfur from combustion waste gases, which comprises cooling said waste gases and forming entrained particles of sodium compounds, consisting essentially of sodium carbonate, by spray contact with sodium hydroxide or sodium carbonate, converting sodium carbonate in the particles to sodium sulfate by passing said oxides of sulphur containing waste gases and said

J. Iwakura; K. Sato; H. Fujii; Y. Hashimoto; S. Ono; S. Watanabe; A. Yokoyama

1977-01-01

91

Development of the CO2 Acceptor Process Directed Towards Low-Sulfur Boiler Fuel.  

National Technical Information Service (NTIS)

The economic and technical feasibility were studied of the adaptation of the CO2 Acceptor Process to the problem of producing low-sulfur, low-Btu power plant fuel by the gasification of bituminous coals. Combustion of fuel gas makes possible a drastic red...

B. Pasek C. E. Fink G. P. Curran J. T. Clancey M. Pell

1971-01-01

92

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

NASA Astrophysics Data System (ADS)

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

Galloway, T. R.

1981-05-01

93

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

SciTech Connect

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

Galloway, T.R.

1981-05-01

94

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, July-September 1984  

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. Work on Task 2 has been completed in June 1984 and has been reported accordingly in DOE/PC/40783-T15. Task 3. Total accounting of the sulfur balance in representative samples of synfuel process streams. A systematic and critical comparison of results, obtained in the analysis of sulfur moieties in representative samples of coal conversion process streams, revealed the following general trends. (a) In specimens of high pH (9-10) and low redox potential (-0.3 to -0.4 volt versus NHE) sulfidic and polysulfidic sulfur moieties predominate. (b) In process streams of lower pH and more positive redox potential, higher oxidation states of sulfur (notably sulfate) account for most of the total sulfur present. (c) Oxidative wastewater treatment procedures by the PETC stripping process convert lower oxidation states of sulfur into thiosulfate and sulfate. In this context, remarkable similarities were observed between liquefaction and gasification process streams. However, the thiocyanate present in samples from the Grand Forks gasifier were impervious to the PETC stripping process. (d) Total sulfur contaminant levels in coal conversion process stream wastewater samples are primarily determined by the abundance of sulfur in the coal used as starting material than by the nature of the conversion process (liquefaction or gasification). 13 references.

Jordan, J.; Talbott, J.

1984-01-01

95

Improved process for the production of cellulose sulfate using sulfuric acid/ethanol solution.  

PubMed

An improved process for production of cellulose sulfate (CS) was developed by using sulfuric acid/ethanol solution as sulfonating agent and Na2SO4 as water absorbent. The FTIR, SEM and TG analysis were used to characterize the CS prepared. The total degree of substitution and viscosity of the product solution (2%, w/v) were ranging from 0.28 to 0.77 and from 115 to 907 mPa s, respectively, by changing the process parameters such as the amount of Na2SO4, the reaction time, the temperature, the sulfuric acid/alcohol ratio and liquid/solid ratio. The results indicated that the product with DS (0.28-0.77) and ?2% (115-907) mPa s could be produced by using this improved process and more cellulose sulfate could be produced when cellulose was sulfonated for 3-4 h at -2 C in sulfuric acid/ethanol (1.4-1.6) solution with addition of 0.8 g Na2SO4. The (13)C NMR indicated that the sulfate group of CS produced using sulfuric acid/ethanol solution was at C6 position. PMID:23618277

Chen, Guo; Zhang, Bin; Zhao, Jun; Chen, Hongwen

2013-06-01

96

Hydrogen production by the GA sulfur-iodine process: a progress report  

Microsoft Academic Search

The progress of the overall total development effort of the General Atomic (GA) sulfur-iodine thermochemical water-splitting cycle over the last two years is summarized. The major accomplishments have been: significant improvements in the chemistry of the process; development, review, and revision of an engineering flowsheet, resulting in a thermal process efficiency of 47%; screening, identification, and testing of potential materials-of-construction

G. E. Besenbruch; K. H. McCorkle; J. H. Norman; D. R. OKeefe; J. R. Schuster; P. W. Trester; M. Yoshimoto

1980-01-01

97

Process for sequestering carbon dioxide and sulfur dioxide  

DOEpatents

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

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

2009-10-20

98

Mixing of Sulfur between Pyritic and Organic Phases during Coal Conversion Processes: Annual Report, March 1-December 31, 1987.  

National Technical Information Service (NTIS)

The mixing of sulfur between the inorganic phase and the organic phase of coal may influence the extent of total sulfur removal during coal conversion processes. This project is designed to determine the extent of such mixing. Continuing studies on the us...

L. V. Dunkerton S. Mehrotra S. Mitra J. B. Phillips K. C. Hackley

1988-01-01

99

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

100

Sulfate-reduction, sulfide-oxidation and elemental sulfur bioreduction process: modeling and experimental validation.  

PubMed

This study describes the sulfate-reducing (SR) and sulfide-oxidizing (SO) process using Monod-type model with best-fit model parameters both being reported and estimated. The molar ratio of oxygen to sulfide (ROS) significantly affects the kinetics of the SR+SO process. The S(0) is produced by SO step but is later consumed by sulfur-reducing bacteria to lead to "rebound" in sulfide concentration. The model correlated well all experimental data in the present SR+SO tests and the validity of this approach was confirmed by independent sulfur bioreduction tests in four denitrifying sulfide removal (DSR) systems. Modeling results confirm that the ratio of oxygen to sulfide is a key factor for controlling S(0) formation and its bioreduction. Overlooking S(0) bioreduction step would overestimate the yield of S(0). PMID:23994962

Xu, Xijun; Chen, Chuan; Lee, Duu-Jong; Wang, Aijie; Guo, Wanqian; Zhou, Xu; Guo, Hongliang; Yuan, Ye; Ren, Nanqi; Chang, Jo-Shu

2013-11-01

101

Partial oxidation process of sulfur, nickel, and vanadium-containing fuels  

Microsoft Academic Search

This patent describes a process for the production of gaseous mixtures. Comprising H+CO by the partial oxidation of a fuel feedstock comprising a heavy liquid hydrocarbonaceous fuel having a nickel and vanadium containing ash or petroleum coke having a nickel and vanadium-containing ash or mixtures thereof; and the feedstock includes a minimum of 0.5 wt. % of sulfur; and the

M. S. Najjar; J. Roland

1989-01-01

102

Global warming potential of the sulfuriodine process using life cycle assessment methodology  

Microsoft Academic Search

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

William C. Lattin; Vivek P. Utgikar

2009-01-01

103

Process for producing dry, sulfur-free, CH[sub 4]-enriched synthesis or fuel gas  

Microsoft Academic Search

A process is described for the production of a dry, sulfur-free methane enriched synthesis gas or fuel gas stream comprising: (1) cooling a particulate-free raw synthesis or fuel gas feed stream comprising H[sub 2], CO, CO[sub 2], H[sub 2]O, N[sub 2], H[sub 2]S, COS and with or without methane to a temperature in the range of about 60 F to

E. T. Child; W. L. Jr. Lafferty; R. M. Suggitt; F. C. Jahnke

1993-01-01

104

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING LAST TECHNICAL REPORT BEFORE NOVATION FROM URS CORP. TO CRYSTATECH, INC  

Microsoft Academic Search

This project was 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 HS in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital

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

2001-01-01

105

Gasoline from natural gas by sulfur processing. Quarterly progress report, June--September 1993  

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 utilize 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 will be generated to demonstrate the potential of catalysts and the overall process. During this first quarter, progress in the following areas has been made. One high surface area molybdenum catalyst has been prepared. An existing unit at IGT is being modified to accommodate the sulfur feedstocks and the higher temperatures(> 1300{degrees}K) required for studying the reactions of hydrogen sulfide and methane as proposed in Tasks 2 through 5. An HP 5890 gas chromatograph with a TCD(thermal conductivity detector) for detecting fixed gases including hydrogen and an FPD(flame photometric detector) for detecting sulfur compounds was purchased using SMP funds and has been received.

Erekson, E.J.; Miao, F.Q.

1993-10-01

106

Pilot and full scale applications of sulfur-based autotrophic denitrification process for nitrate removal from activated sludge process effluent.  

PubMed

Sulfur-based autotrophic denitrification of nitrified activated sludge process effluent was studied in pilot and full scale column bioreactors. Three identical pilot scale column bioreactors packed with varying sulfur/lime-stone ratios (1/1-3/1) were setup in a local wastewater treatment plant and the performances were compared under varying loading conditions for long-term operation. Complete denitrification was obtained in all pilot bioreactors even at nitrate loading of 10mg [Formula: see text] -N/(L.h). When the temperature decreased to 10C during the winter time at loading of 18mg [Formula: see text] -N/(L.h), denitrification efficiency decreased to 60-70% and the bioreactor with S/L ratio of 1/1 gave slightly better performance. A full scale sulfur-based autotrophic denitrification process with a S/L ratio of 1/1 was set up for the denitrification of an activated sludge process effluent with a flow rate of 40m(3)/d. Almost complete denitrification was attained with a nitrate loading rate of 6.25mg [Formula: see text] -N/(L.h). PMID:24862952

Sahinkaya, Erkan; Kilic, Adem; Duygulu, Bahadir

2014-09-01

107

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING LAST TECHNICAL REPORT BEFORE NOVATION FROM URS CORP. TO CRYSTATECH, INC.  

SciTech Connect

This project was funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of Gas Research Institute) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane while avoiding methane oxidation. The project involved the development of a detailed plan for laboratory and bench scale-up application, laboratory/bench-scale catalyst testing, and demonstration of scale-up economic advantages. The bench-scale tests examined two different catalysts that are promoted modifications of TDA's patented partial oxidation catalyst used to make elemental sulfur. The experiments showed that catalyst TDA No.2 is superior for use with the hybrid CrystaSulf process in that much higher yields of SO{sub 2} can be obtained. Continued testing is planned.

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

2001-02-01

108

A new biological phosphorus removal process in association with sulfur cycle.  

PubMed

Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction Autotrophic denitrification and Nitrification Integrated (SANI()) process with minimal sludge production. This study seeks to expand the SANI process into an enhanced biological phosphorus removal (EBPR) process. A sulfur cycle associated EBPR was explored in an alternating anaerobic/oxygen-limited aerobic sequencing batch reactor with acetate fed as sole electron donor and sulfate as sulfur source at a total organic carbon to sulfur ratio of 1.1-3.1 (mg C/mg S). Phosphate uptake and polyphosphate formation was observed in this reactor that sustained high phosphate removal (20 mg P/L removed with 320 mg COD/L). This new EBPR process was supported by six observations: 1) anaerobic phosphate release associated with acetate uptake, poly-phosphate hydrolysis, poly-hydroxyalkanoate (PHA) (and poly-S(2-)/S(0)) formation and an "aerobic" phosphate uptake associated with PHA (and poly-S(2-)/S(0)) degradation, and polyphosphate formation; 2) a high P/VSS ratio (>0.16 mg P/mg VSS) and an associated low VSS/TSS ratio (0.75) characteristic of conventional PAOs; 3) a lack of P-release and P-uptake with formaldehyde inactivation and autoclaved sterilized biomass; 4) an absence of chemical precipitated P crystals as determined by XRD analysis; 5) a sludge P of more than 90% polyphosphate as determined by sequential P extraction; and 6) microscopically, observed PHA, poly-P and S globules in the biomass. PMID:23579090

Wu, Di; Ekama, George A; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

2013-06-01

109

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, January-March 1984  

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. Work is in progress on the polarography of the polythionates. Results will be presented in a forthcoming Quarterly Report. Task 3. Total accounting of the sulfur balance in representative samples of synfuel process streams. Two aqueous samples emanating from different stages of the Lummus Process were analyzed. As expected, total sulfur content was low, viz., 0.006 M and 0.001 M. Concentrations of sulfidic sulfur, polysulfidic sulfur, thiosulfate, sulfite, trithionate, tetrathionate, and pentathionate were less than 0.001 M each. 5 references, 3 tables.

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

1984-04-01

110

H{sub 2}S-removal and sulfur-recovery processes using metal salts  

SciTech Connect

Scrubbing a sour gas stream with a solution of copper sulfate allows the clean-up temperature to be increased from ambient to the adiabatic saturation temperature of the gas. The copper ion in solution reacts with the H{sub 2}S to produce insoluble CuS. The choice of copper sulfate was set by the very low solubility of CuS and the very rapid kinetics of the Cus formation. Since the copper sulfate solutions used are acidic, CO{sub 2} will not be co-absorbed. In a subsequent step the solid CuS is oxidized by a solution of ferric sulfate. The copper sulfate is regenerated, and elemental sulfur is formed together with ferrous sulfate. The ferrous sulfate is reoxidized to ferric sulfate using air. Since the copper sulfate and ferric solutions are regenerated, the overall reaction in this process is the oxidation of hydrogen sulfide with oxygen to form sulfur. The use of copper sulfate has the further advantage that the presence of sulfuric acid, even as concentrated as 1 molar, does not inhibit the sorption of H{sub 2}S. Furthermore, the absorption reaction remains quite favorable thermodynamically over the temperature range of interest. Because the reaction goes to completion, only a single theoretical stage is required for complete H{sub 2}S removal and cocurrent gas/liquid contacting may be employed. The formation of solids precludes the use of a packed column for the contacting device. However, a venturi scrubber would be expected to perform satisfactorily. The kinetics of the oxidation of metal sulfides, in particular zinc and copper sulfide, is reported in the literature to be slow at near-ambient temperatures. The proposed process conditions for the oxidation step are different from those reported in the literature, most notably the higher temperature. The kinetics of the reaction must be studied at high temperatures and corresponding pressures. An important goal is to obtain sulfur of high purity, which is a salable product.

Lynn, S.; Cairns, E.J.

1992-11-01

111

H[sub 2]S-removal and sulfur-recovery processes using metal salts  

SciTech Connect

Scrubbing a sour gas stream with a solution of copper sulfate allows the clean-up temperature to be increased from ambient to the adiabatic saturation temperature of the gas. The copper ion in solution reacts with the H[sub 2]S to produce insoluble CuS. The choice of copper sulfate was set by the very low solubility of CuS and the very rapid kinetics of the Cus formation. Since the copper sulfate solutions used are acidic, CO[sub 2] will not be co-absorbed. In a subsequent step the solid CuS is oxidized by a solution of ferric sulfate. The copper sulfate is regenerated, and elemental sulfur is formed together with ferrous sulfate. The ferrous sulfate is reoxidized to ferric sulfate using air. Since the copper sulfate and ferric solutions are regenerated, the overall reaction in this process is the oxidation of hydrogen sulfide with oxygen to form sulfur. The use of copper sulfate has the further advantage that the presence of sulfuric acid, even as concentrated as 1 molar, does not inhibit the sorption of H[sub 2]S. Furthermore, the absorption reaction remains quite favorable thermodynamically over the temperature range of interest. Because the reaction goes to completion, only a single theoretical stage is required for complete H[sub 2]S removal and cocurrent gas/liquid contacting may be employed. The formation of solids precludes the use of a packed column for the contacting device. However, a venturi scrubber would be expected to perform satisfactorily. The kinetics of the oxidation of metal sulfides, in particular zinc and copper sulfide, is reported in the literature to be slow at near-ambient temperatures. The proposed process conditions for the oxidation step are different from those reported in the literature, most notably the higher temperature. The kinetics of the reaction must be studied at high temperatures and corresponding pressures. An important goal is to obtain sulfur of high purity, which is a salable product.

Lynn, S.; Cairns, E.J.

1992-01-01

112

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 42.75C, an aqueous ammonia concentration of 20.93%, and a reaction time of 48h. 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.

2013-01-01

113

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

SciTech Connect

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

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

1983-01-01

114

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 Earths 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 (2040). 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.

Halevy, Itay

2013-01-01

115

Photosynthetic bioconversion sulfur removal  

SciTech Connect

A photosynthetic bioconversion process is described for removal of sulfur compounds from a gas stream comprising carbon oxide and reductive sulfur compounds. The process comprises: contacting the gas stream consisting of carbon oxide compounds and reductive sulfur compounds with an active culture of photosynthetic bacteria capable of utilizing the reductive sulfur compound as its sole source of reducing electrons and the carbon oxides as its sole source of carbon for growth under substantially anaerobic conditions with electromagnetic radiation. The reductive sulfur compound provides the sole source of reducing electrons and the carbon oxides provide the sole source of carbon for growth and cultivating the bacteria to form elemental sulfur and organic carbon compounds.

Cork, D.J.

1987-05-19

116

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 are described 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 mixture.

Cohen, M.R.; Gal, E.

1993-04-13

117

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) [Troy, NY; Gal, Eli (Lititz, PA) [Lititz, PA

1993-01-01

118

Hydrogen generation process. Quarterly technical progress report, August 17, 1976November 16, 1976. [Sulfur cycle water decomposition system  

Microsoft Academic Search

The objective of this program is to assess the technical and economic feasibility of a hybrid electrolytic-thermochemical hydrogen generation process based upon the electrolysis of sulfurous acid. To do this, a multi-task program is being carried out to experimentally determine the operating characteristics of key process steps in the hydrogen generating cycle and to perform engineering and economic analyses to

Koump

1976-01-01

119

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

120

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

SciTech Connect

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. A literature search and theoretical evlauation were conducted to identify the chemical/physical conditions and flow characteristics of entrained-bed slagging gasification as they relate to in-process control of NOx and SOx precursors. However, the degree of success of the suggested in-process controls could not be projected. The applicability of potential in-process control was examined. It was concluded that in-process controls, if feasible, are applicable for reducing NOx and SOx precursors so that the capacities of downstream control devices can be reduced with subsequent cost savings.

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

1986-12-01

121

Removal of Sulfur from CaF2 Containing Desulfurization Slag Exhausted from Secondary Steelmaking Process by Oxidation  

NASA Astrophysics Data System (ADS)

The oxidation behavior of sulfur in desulfurization slag generated from the secondary steelmaking process with air has been investigated in the temperature range of 973 K to 1373 K (700 C to 1100 C). Although a high removal rate of sulfur is not achieved at temperatures lower than 1273 K (1000 C) because of the formation of CaSO4, most of the sulfur is rapidly removed from slag as SO2 gas in the 1273 K to 1373 K (700 C to 1100 C) range. This finding indicates that the desulfurization slag generated from the secondary steelmaking process can be reused as a desulfurized flux through air oxidation, making it possible to reduce significantly the amount of desulfurization slag for disposal.

Hiraki, Takehito; Kobayashi, Junichi; Urushibata, Satomi; Matsubae, Kazuyo; Nagasaka, Tetsuya

2012-08-01

122

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

123

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

124

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

125

Sulfur barrier for use with in situ processes for treating formations  

DOEpatents

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

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

2009-12-15

126

Economic and Technical Evaluation of the Sulfurous Acid-Caustic Purification Process for Producing Alumina from Kaolinitic Clay.  

National Technical Information Service (NTIS)

An economic and technical evaluation of a proposed process to recover alumina by leaching calcined kaolinitic clay with sulfurous acid is presented in this Bureau of Mines report. After the insoluble portion of the clay has been removed by leaching, monob...

D. A. Kramer

1983-01-01

127

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...

128

Molecular sieve control process in sulfuric acid plants. Final report, Oct 1974--Oct 1975  

Microsoft Academic Search

The report gives results of an engineering analysis of the applicability of molecular sieve technology to the control of SO emissions from sulfuric acid plants. After the equivalent of 10 months of operation, one plant using this technology is still controlling SO emissions to well within Federal and State regulations for sulfuric acid plants. It is also meeting the performance

Hissong

1975-01-01

129

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 ...

130

[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

131

Molecular Structure of sulfur  

NSDL National Science Digital Library

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

2002-08-26

132

Reactions for Improving Efficiencies in Thermochemical Cycles Related to the Sulfur Dioxide-Iodine Process.  

National Technical Information Service (NTIS)

A modification of the sulfur dioxide-iodine cycle which uses magnesium oxide, magnesium sulfite and magnesium iodide is examined with particular emphasis on decreasing the amount of water employed and thereby increasing the efficiency. The key reaction is...

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

1982-01-01

133

Hydrogen Production by the GA Sulfur-Iodine Process: A Progress Report.  

National Technical Information Service (NTIS)

The progress of the overall total development effort of the General Atomic (GA) sulfur-iodine thermochemical water-splitting cycle over the last two years is summarized. The major accomplishments have been: significant improvements in the chemistry of the...

G. E. Besenbruch K. H. McCorkle J. H. Norman D. R. O'Keefe J. R. Schuster

1980-01-01

134

Conceptual design of a reactive distillation process for ultra-low sulfur diesel production  

Microsoft Academic Search

Based on a thermodynamic analysis in terms of reaction-separation feasibility, a conceptual design of a reactive distillation column for ultra-low sulfur diesel production has been developed. The thermodynamic analysis considers the computation of reactive and non-reactive residue curve maps for a mixture that models the sulfured diesel fuel. The visualization of the reactive residue curves is posed in terms of

Toms Viveros-Garca; J. Alberto Ochoa-Tapia; Ricardo Lobo-Oehmichen; J. Antonio de los Reyes-Heredia; Eduardo S. Prez-Cisneros

2005-01-01

135

A new process for converting SO2 to sulfur without generating secondary pollutants through reactions involving CaS and CaSO4.  

PubMed

Nonferrous smelters and coal gasification processes generate environmentally harmful sulfur dioxide streams, most of which are treated to produce sulfuric acid with the accompanying problems of market shortage and transportation difficulties. Some sulfur dioxide streams are scrubbed with an alkali solution or a solid substance such as limestone or dolomite, which in turn generates wastes that pose other pollution problems. While the conversion of sulfur dioxide to elemental sulfur has many environmental advantages, no processes exist that are environmentally acceptable and economically viable. A new method for converting sulfur dioxide to elemental sulfur by a cyclic process involving calcium sulfide and calcium sulfate without generating solid wastes has been developed. In this process, calcium sulfate pellets as the starting raw material are reduced by a suitable reducing agent such as hydrogen to produce calcium sulfide pellets, which are used to reduce sulfur dioxide producing elemental sulfur vapor and calcium sulfate. The latter is then reduced to regenerate calcium sulfide. Thermodynamic analysis and experimental results indicated that the CaS-SO2 reaction produces mainly sulfur vapor and solid calcium sulfate and that the gaseous product from the CaSO4-H2 reaction is mainly water vapor. The rates of the two reactions are reasonably rapid in the temperature range 1000-1100 K, and, importantly, the physical strengths and reactivities of the pellets are maintained largely unchanged up to the tenth cycle, the last cycle tested in this work. Sulfur dioxide-containing streams from certain sources, such as the regenerator off-gas from an integrated gasification combined cycle desulfurization unit and new sulfide smelting plants, contain much higher partial pressures of SO2. In these cases, the rate of the first reaction is expected to be proportionally higher than in the test conditions reported in this paper. PMID:12144280

Sohn, H Y; Kim, Byung-Su

2002-07-01

136

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

137

[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

138

A novel three phase fluidized bed process for simultaneous selective flocculation and microbial desulfurization of high sulfur coal. Final report  

SciTech Connect

The purpose of this work was to investigate the feasibility of recovery and reclamation of ultrafine coal particles generated during the processing of coal. 10--35% of the total annual tonnage of coal in atypical coal preparation plant is estimated to be lost in forms of ultrafine particles during the mining, shipping, handling, and preparation of the coal. The technical feasibility of the proposed system which consisted of an integrated circuit of selective flocculation followed by microbial desulfurization, has been tested. The results indicate that using selective flocculation/froth flotation circuit, coal recoveryis 85% with 75% pyritic sulfur and 60% ash rejections. The remaining pyritic sulfur in the coal slurry was treated using microbial desulfurization in a draft-tube fluidized bed bioreactor. Using this reactor scheme considerable enhancement of the bioleaching rate was obtained. The results indicate that 90% rejection of pyritic sulfur can be achieved in less than 24 hrs. Note that the previously reported data for the bioleaching rate are from 4 to 12 days for the same amount of pyritic rejection. The results obtained in this work closely reflects the anticipated outcomes which were projected in the original proposal. Consequently, the results of this work implies a significant improvement in bioleaching process and the possibility for the commercialization of the microbial desulfurization process. Our results also indicate further improvement of this process by optimization of reactor sequence and operating conditions.

Fan, Liang-Shih; Bavarian, F.; Attia, Y.A.; Elzeky, M. [Ohio State Univ., Columbus, OH (United States)

1990-10-16

139

A novel three phase fluidized bed process for simultaneous selective flocculation and microbial desulfurization of high sulfur coal  

SciTech Connect

The purpose of this work was to investigate the feasibility of recovery and reclamation of ultrafine coal particles generated during the processing of coal. 10--35% of the total annual tonnage of coal in atypical coal preparation plant is estimated to be lost in forms of ultrafine particles during the mining, shipping, handling, and preparation of the coal. The technical feasibility of the proposed system which consisted of an integrated circuit of selective flocculation followed by microbial desulfurization, has been tested. The results indicate that using selective flocculation/froth flotation circuit, coal recoveryis 85% with 75% pyritic sulfur and 60% ash rejections. The remaining pyritic sulfur in the coal slurry was treated using microbial desulfurization in a draft-tube fluidized bed bioreactor. Using this reactor scheme considerable enhancement of the bioleaching rate was obtained. The results indicate that 90% rejection of pyritic sulfur can be achieved in less than 24 hrs. Note that the previously reported data for the bioleaching rate are from 4 to 12 days for the same amount of pyritic rejection. The results obtained in this work closely reflects the anticipated outcomes which were projected in the original proposal. Consequently, the results of this work implies a significant improvement in bioleaching process and the possibility for the commercialization of the microbial desulfurization process. Our results also indicate further improvement of this process by optimization of reactor sequence and operating conditions.

Fan, Liang-Shih; Bavarian, F.; Attia, Y.A.; Elzeky, M. (Ohio State Univ., Columbus, OH (United States))

1990-10-16

140

Mixing of sulfur between pyritic and organic phases during coal conversion processes: Annual report, March 1--December 31, 1987  

SciTech Connect

The mixing of sulfur between the inorganic phase and the organic phase of coal may influence the extent of total sulfur removal during coal conversion processes. This project is designed to determine the extent of such mixing. Continuing studies on the use of substituted dibenzothiophenes to monitor mixing of sulfur between pyritic and organic phases has primarily focused on using labeled sulfur compounds to monitor the migration from organic compounds to the iron sulfide. To distinguish migration of more easily desulfurized types from thiophenic sulfur, /sup 34/S labeled compounds were prepared from dibenzothiophene with a /sup 34/S labeled easily desulfurized group attached. The hydrodesulfurization with and without troilite in a model coal environment is being studied. This experiment required that isotope ratio analysis techniques be adapted to monitoring the ratio of H/sub 2//sup 32/S to H/sub 2//sup 34/S during hydrodesulfurization as well as analyzing the isotope ratio of the solid residues. Quadrupole mass spectrometer detection was carried out and the results compared to those obtained from multiplex gas chromatography detection. Both techniques showed thiomethyl group desulfurization occurring between 523K and 600K while the thiophenic group slowly began to desulfurize around 725K. The synthesis of labeled dibenzothiophene from 2,2' biphenyl and /sup 34/S was achieved in 54% yield, and this method is also applicable to preparation of /sup 33/S labeled dibenzothiophene for a /sup 33/S NMR enriched sample. The synthesis of /sup 34/S labeled dibenzothiophene from 2,2'dinitrobiphenyl has progressed through the preparation of 2-aminobiphenyl-2'-thiol in which the label was introduced from /sup 34/S thiourea. 23 refs., 4 figs.

Dunkerton, L.V.; Mehrotra, S.; Mitra, S.; Phillips, J.B.; Hackley, K.C.

1988-03-01

141

Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.  

PubMed

Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25mgSO4(2-)/mgCOD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI()) process with minimal sludge production and oxygen demand. Recently, the SANI() process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0mgP/mgS. There were no conventional PAOs in the sludge. PMID:24342048

Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

2014-02-01

142

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

143

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

SciTech Connect

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

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

1980-05-01

144

ADVANCED SULFUR CONTROL CONCEPTS  

SciTech Connect

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

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

2003-01-01

145

Sulfur Isotopes as Indicators of Bacterial Sulfate Reduction Processes Influencing Field Scale Uranium Bioremediation  

NASA Astrophysics Data System (ADS)

An in-situ acetate amendment at a DOE Uranium Mill Tailings Remedial Action (UMTRA) site near Rifle, CO demonstrated successful reduction of aqueous U(VI), to less soluble U(IV) through stimulated microbial activity. U(VI) reduction rates were highest during iron reduction and decreased with the onset of sulfate reduction. However, sustained U(IV) attenuation was observed following subsequent termination of the acetate amendment. These findings illustrate the importance of the transition between iron and sulfate reducing conditions in stimulating bioreduction of uranium. The sulfur isotope compositions of sulfate and sulfide were measured through this transition in order to explore the utility of these data in tracking the extent of microbial sulfate reduction and to assess the stability of sulfide precipitates. Samples for isotopic analyses and aqueous measurements of sulfate, ferrous iron, U(VI) and acetate were collected in one background well and three monitoring wells down-gradient of the acetate injection. Results show an increase of up to 7 in the ?34S of sulfate at the onset of sulfate reduction, followed by a return to background ?34S values of -8 following cessation of the acetate amendment. The ?34S values of sulfide increased from roughly -20 at the onset of sulfate reduction to a maximum of -0.8 during peak sulfate removal, followed by a gradual return to values of roughly -28 upon cessation of the acetate amendment. These data present a unique perspective on the processes governing the bioreduction experiment in that the sulfate isotopes are a function of both transport and mixing processes, whereas the sulfide isotopes represent biogenic sulfide that is rapidly removed from the aqueous phase. Thus a comparable enrichment in sulfate isotopic data noted in the closest and furthest wells from the injection gallery suggest bioreduction in both of these locations, while a larger increase in sulfide isotopic values in the closest well indicates greater rates of sulfate reduction closer to the injection gallery. In addition, a steady decline in ?34S of sulfide concurrent with increased sulfide concentrations following cessation of acetate amendment suggests that this increase is not a result of reoxidation of precipitated FeS species. FeS precipitates formed during the height of sulfate reduction therefore appear to be stable on a timeframe of months following acetate amendment and may support the stability and long-term sequestration of precipitated U(IV).

Druhan, J. L.; Conrad, M. E.; Williams, K. H.; N'guessan, L.; Long, P. E.; Hubbard, S. S.

2007-12-01

146

Hydrogen Production by the GA Sulfur-Iodine Process: A Progress Report.  

National Technical Information Service (NTIS)

A summary of the progress of the overall total development effort of the General Atomic (GA) sulfur-iodine thermochemical water-splitting cycle over the last two years is reported. The major accomplishments have been the following: (1) Significant improve...

G. E. Besenbruch K. H. McCorkle J. H. Norman D. R. O'Keefe J. R. Schuster

1980-01-01

147

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

Microsoft Academic Search

A modification of the sulfur dioxide iodine cycle which uses magnesium oxide, magnesium sulfite and magnesium iodide is examined with particular emphasis on decreasing the amount of water employed and thereby increasing the efficiency. The key reaction is that of iodine with magnesium oxide and magnesium sulfite hexahydrate with no additional water. This produces 77% of the total possible sulfate

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

1982-01-01

148

Coal liquefaction process streams characterization and evaluation: Investigation of the forms of sulfur in five Wilsonville resid samples by XAFS and moessbauer spectroscopy  

SciTech Connect

This study demonstrated the feasibility of using XAFS and Moessbauer spectroscopy for the examination of distillation resid materials derived from direct coal liquefaction. The least-squares analysis of the XANES region of the K-shell XAFS spectra was shown to be technique which can be used to determine the sulfur forms in coal liquefaction-derived resid samples. The large amount of pyrrhotite in the resid samples (71 to 99% [plus minus]10% of the total sulfur) interfered with the precise quantitative analysis of the organic sulfur. However, a spectral subtraction routine was successfully used to provide semi-quantitative results for sulfur species other than the pyrrhotite. Moessbauer spectroscopy, considered a more accurate method than XAFS for the quantitative analysis of inorganic iron-sulfur species (pyrite, pyrrhotite, iron sulfates), was successfully used to speciate these materials in the coal liquefaction resids. Further application of XAFS and Moessbauer spectroscopy as process development tools appears justified by these results.

Huffman, G.P.; Huggins, F.E.; Shah, N. (Kentucky Univ., Lexington, KY (United States). Consortium for Fossil Fuel Science)

1992-11-01

149

Coal liquefaction process streams characterization and evaluation: Investigation of the forms of sulfur in five Wilsonville resid samples by XAFS and moessbauer spectroscopy  

SciTech Connect

This study demonstrated the feasibility of using XAFS and Moessbauer spectroscopy for the examination of distillation resid materials derived from direct coal liquefaction. The least-squares analysis of the XANES region of the K-shell XAFS spectra was shown to be technique which can be used to determine the sulfur forms in coal liquefaction-derived resid samples. The large amount of pyrrhotite in the resid samples (71 to 99% {plus_minus}10% of the total sulfur) interfered with the precise quantitative analysis of the organic sulfur. However, a spectral subtraction routine was successfully used to provide semi-quantitative results for sulfur species other than the pyrrhotite. Moessbauer spectroscopy, considered a more accurate method than XAFS for the quantitative analysis of inorganic iron-sulfur species (pyrite, pyrrhotite, iron sulfates), was successfully used to speciate these materials in the coal liquefaction resids. Further application of XAFS and Moessbauer spectroscopy as process development tools appears justified by these results.

Huffman, G.P.; Huggins, F.E.; Shah, N. [Kentucky Univ., Lexington, KY (United States). Consortium for Fossil Fuel Science

1992-11-01

150

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

SciTech Connect

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

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

2010-01-10

151

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

NASA Astrophysics Data System (ADS)

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 show that this species is a product of radiolysis. Sulfuric acid on Europa occurs as the radiolytically stable octahydrate and hemihexahydrate and is a major surface component, along with water ice. The sulfuric acid concentration correlates spatially with Europa's visually dark material, which we identify as radiolytically altered sulfur polymers. Radiolysis by incident jovian plasma continuously cycles sulfur between three chemical reservoirs: sulfuric acid, polymerized sulfur, and sulfur dioxide, with the acid being about 50 times more abundant than the other forms because of the stability of the sulfate anion under irradiation. The original source of sulfur may be incident iogenic sulfur ions or endogenic sulfur compounds that are altered by radiolysis. Geological processes can bury and redistribute the sulfurous material, producing a sulfur-rich crust and a non-uniform surface distribution. The low melting point of sulfuric acid and its ability to supercool may facilitate geological processes. Europa's magnetic response may be influenced by the electrical conductivity of sulfuric acid.

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

1999-09-01

152

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

153

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

154

Process model-free analysis for thermodynamic efficiencies of sulfuriodine processes for thermochemical water decomposition  

Microsoft Academic Search

Material, energy, and entropy balances, which depend only on stream conditions and flows entering and leaving a system, have been used to evaluate different scenarios for thermochemical decomposition of water to manufacture hydrogen using the SulfurIodine cycle. Energy efficiencies have been found for idealized systems with variable stream amounts, as well as for a common flowsheet, to locate the greatest

John P. O'Connell; Parinya Narkprasert; Maximilian B. Gorensek

2009-01-01

155

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

156

Gasoline from natural gas by sulfur processing. Quarterly report No. 5 for the period July 1994--September 1994  

SciTech Connect

Natural gas is an abundant resource in various parts of the world. The major component of natural gas is methane, often comprising over 90% of the hydrocarbon fraction of the gas. The expanded use of natural gas as fuel is often hampered because of difficulties in storing and handling a gaseous fuel. This is especially true for natural gas in remote areas such as the North Slope of Alaska. The successful implementation of a natural gas-to-gasoline process would decrease dependence on imported oil for transportation fuels. These factors make it very desirable to convert natural gas to more valuable liquids. There are commercial processes for converting natural gas to gasoline-range liquids. These processes, such as the Fischer-Tropsch synthesis and Mobil`s MTG (Methanol To Gasoline), start with the steam reforming of methane. Steam reforming of methane requires the removal of sulfur compounds present in natural gas down to less than 0.1 ppm. This additional gas cleanup step, with its additional cost, is necessary because the catalysts are quickly poisoned by sulfur compounds.

Erekson, E.J.; Miao, F.Q.

1994-10-01

157

Bacteria morphology and diversity of the combined autotrophic nitritation and sulfur-carbon three-dimensional-electrode denitrification process.  

PubMed

The bacterial morphology and diversity in the reactors of a combined autotrophic nitritation and sulfur-carbon three-dimensional-electrode denitrification (CANSCTED) process operating under steady-state conditions were investigated by scanning electron microscopy and partial 16S rDNA cloning and sequencing. The CANSCTED process consisted of two parts, i.e., the nitritation membrane bioreactor (NMBR) and the sulfur-carbon three-dimensional-electrode denitrification reactor (SCTED). When the influent NH?(+) concentration of NMBR ranged from 854 to 1086 mg N L(-1), with about 50% NH?(+) removal efficiency and NO?(-) accumulation rate, the spherical and spheroidal ammonia-oxidizing bacteria were predominant, with community successions of ?-Proteobacteria (60.0%), Bacteroidetes (28.3%) and Chloroflexi (11.7%). The NMBR effluent with 429?543 mg N L(-1) NH?(+) and 519?578 mg N L(-1) NO?(-) was continuously supplied to SCTED for sulfur denitrification, bioelectrochemical hydrogen denitrification, and anaerobic ammonium oxidation. The predominant bacterial community successions were ?-Proteobacteria (78.3%) and ?-Proteobacteria (21.7%). When the SCTED influent was supplied with only NO?(-) (412-525 mg N L(-1)) as nitrogen substrate, the predominant bacteria in SCTED were short-bacilliform and spheroidal denitrification bacteria, ?-Proteobacteria (82.0%), ?-Proteobacteria (16.4%) and ?-Proteobacteria (1.6%). Although the predominant bacterial communities were both ?-Proteobacteria and ?-Proteobacteria in SCTED, the species and quantity of each community varied with the change of SCTED influent composition, which indicated that the composition influence the bacterial morphology and diversity in SCTED. PMID:24117082

Wang, Haiyan; Zhou, Yuexi; Yuan, Quan; Zhao, Hua; Dai, Xin

2014-01-01

158

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

NASA Astrophysics Data System (ADS)

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

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

1982-06-01

159

Fractionation of sulfur isotopes during atmospheric processes: SO2 oxidation and photolysis  

NASA Astrophysics Data System (ADS)

Measurements of stable sulfur isotopes can be used to investigate the chemistry of SO2 in the environment. The oxidation pathway of SO2 plays an important role in determining its environmental effect: gaseous oxidation by OH radicals produces gas-phase sulfuric acid that can nucleate to produce new particles and CCN, while heterogeneous oxidation can change the surface properties of existing particles. Stable isotopes have been used in the investigation of these oxidation pathways, but a major limitation is the lack of laboratory studies of the isotopic fractionation factor for the gaseous reaction (Castleman et al., 1974; Leung et al., 2001; Tanaka et al., 1994). An experimental set-up to investigate the kinetic fractionation of 34S/32S (? = k34/k32) during this reaction has been developed. OH radicals are generated by flowing humidified nitrogen past a mercury lamp producing high-energy UV light. SO2 gas with a known isotopic composition reacts with the OH radicals to produce sulfuric acid gas. Collection methods for both H2SO4 and SO2 gases have been characterised. H2SO4 gas is collected in a glass condenser system and washed out with MilliQ water. This collection method introduces no significant isotopic fractionation. SO2 gas is collected in two bubblers containing 6% H2O2 solution at 273 K, which introduces fractionation of 13 2 (? = 1.013 0.002) at 273 K, agreeing with aqueous uptake and oxidation (Saltzman et al., 1983). Following collection, BaCl2 is added to precipitate the sulfur as BaSO4 and the solutions are filtered to collect the BaSO4 grains for analysis in the NanoSIMS. Photolytic and aqueous oxidation of SO2 are the main interfering reactions occurring in the system, and were investigated by running the reaction set-up without generating OH radicals. High humidity conditions produce fractionation of 11 7 (? = 1.011 0.007) at 293 K, which corresponds well with previous results for the SO2(g)-HSO3-(aq) system (Eriksen, 1972). Comparison with SO2 collection fractionation gives a temperature dependency of 0.1/K. At lower humidity the mass-independent signature of the photolytic reaction (Farquhar et al., 2001) is clearly seen, with little interference from the aqueous reaction. After consideration of these interferences, the fractionation during oxidation of SO2 by OH radicals was measured to be 9.8 2.9 (? = 1.098 0.0029) at 273 K, with a temperature dependency of 0.09 0.12 /K.

Harris, E. J.; Sinha, B.; Hoppe, P.; Crowley, J.; Foley, S. F.

2010-12-01

160

Initial Assessment of Sulfur-Iodine Process Safety Issues and How They May Affect Pilot Plant Design and Operation  

SciTech Connect

The sulfur-iodine process to make hydrogen by the thermochemical splitting of water is under active development as part of a U.S. Department of Energy program. An integrated lab scale system is currently being designed and built. The next planned stage of development is a pilot plant with a thermal input of about 500 kW, equivalent to about 30,000 standard liters per hour of hydrogen production. The sulfur-iodine process contains a variety of hazards, including temperatures up to 850 C and hazardous chemical species including SO2, H2SO4, HI, I2, and of course H2. The siting and design of a pilot plant must consider these and other hazards. This report presents an initial analysis of the hazards that might affect pilot plant design and should be considered in the initial planning. The general hazards that have been identified include reactivity, flammability, toxicity, pressure, electrical hazards, and industrial hazards such as lifting and rotating equipment. Personnel exposure to these hazards could occur during normal operations, which includes not only running the process at the design conditions but also initial inventory loading, heatup, startup, shutdown, and system flushing before equipment maintenance. Because of the complexity and severity of the process, these ancillary operations are expected to be performed frequently. In addition, personnel could be exposed to the hazards during various abnormal situations which could include unplanned phase changes of liquids or solids, leaks of process fluids or cooling water into other process streams, unintentional introducion of foreign species into the process, and unexpected side reactions. Design of a pilot plant will also be affected by various codes and regulations such as the International Building Code, the International Fire Code, various National Fire Protection Association Codes, and the Emergency Planning and Community Right-to-Know Act.

Robert S. Cherry

2006-09-01

161

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

162

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

163

Sulfur isotope analysis of individual aerosol particles - a new tool for studying heterogeneous oxidation processes in the marine environment  

NASA Astrophysics Data System (ADS)

Understanding the importance of the different oxidation pathways of sulfur dioxide (SO2) to sulfate is crucial for an interpretation of the climate effects of sulfate aerosols. Sulfur isotope analysis of atmospheric aerosol is a well established tool for identifying sources of sulfur in the atmosphere and assessment of anthropogenic influence. The power of this tool is enhanced by a new ion microprobe technique that permits isotope analysis of individual aerosol particles as small as 0.5 ?m diameter. With this new single particle technique, different types of primary and secondary sulfates are first identified based on their chemical composition, and then their individual isotopic signature is measured. Our samples were collected at Mace Head, Ireland, a remote coastal station on the North Atlantic Ocean. Sea-salt-sulfate (10-60%), ammonium sulfate/sulfuric acid particles (15-65%), and non-sea-salt-sulfate (nss-sulfate) on aged salt particles all contributed significantly to sulfate loadings in our samples. The isotopic composition of secondary sulfates depends on the isotopic composition of precursor SO2 and the oxidation process. The fractionation with respect to the source SO2 is poorly characterized. In the absence of conclusive laboratory experiments, we consider the kinetic fractionation of -9 during the gas phase oxidation of SO2 by OH as suggested by Saltzman et al. (1983) and Tanaka et al. (1994) to be the most reasonable estimate for the isotope fractionation during gas phase oxidation of SO2 (?hom=0.991) and the equilibrium fractionation for the uptake of SO2(g) into the aqueous phase and the dissociation to HSO3- of +16.5 measured by Eriksen (1972a) to be the best approximation for the fractionation during oxidation in the aqueous phase (?het=1.0165). The sulfur isotope ratio of secondary sulfate particles can therefore be used to identify the oxidation pathway by which this sulfate was formed. However, the fraction of heterogeneous and homogeneous oxidation pathway calculated is very sensitive to the isotope fractionation assumed for both pathways. Particles with known oxidation pathway (fine mode ammonium sulfate) are used to estimate the isotopic composition of the source SO2. It ranged from ?34SVCDT=03 to ?34SVCDT=(143) under clean conditions and ?34SVCDT=(31) under polluted condition. Condensation of H2SO4(g) onto sea salt aerosol produces an isotopic ratio that, when plotted against the sea-salt-sulfate content of the sample, lies on a mixing line between sea salt and ammonium sulfate. The contribution of heterogeneous oxidation is estimated based on the deviation of non-sea-salt-sulfate from this isotopic mixing line. The contribution of heterogeneous oxidation to nss-sulfate formation on aged sea salt sodium sulfate, magnesium sulfate gypsum and mixed sulfate particles under clean conditions is on average 10% for coarse and 25% for fine mode particles. Under polluted conditions, the contribution of heterogeneous oxidation to nss-sulfate formation increased to 60% on coarse mode and 75% on fine mode particles. However, large day-to-day variations in the contribution of heterogeneous oxidation to nss-sulfate formation occurred. Our results suggest that a~significant portion of SO2 in coastal regions is converted to fine mode ammonium sulfate/sulfuric acid particles (40-80% of nss-sulfate) and that condensation of H2SO4(g) contributes significantly even to the nss-sulfate in aged sea salt particles (20-85%).

Sinha, B. W.; Hoppe, P.; Huth, J.; Foley, S.; Andreae, M. O.

2009-02-01

164

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

SciTech Connect

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

Gorensek, M

2007-03-16

165

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

166

Calcium looping process for high purity hydrogen production integrated with capture of carbon dioxide, sulfur and halides  

DOEpatents

A process for producing hydrogen comprising the steps of: (i) gasifying a fuel into a raw synthesis gas comprising CO, hydrogen, steam, sulfur and halide contaminants in the form of H.sub.2S, COS, and HX, wherein X is a halide; (ii) passing the raw synthesis gas through a water gas shift reactor (WGSR) into which CaO and steam are injected, the CaO reacting with the shifted gas to remove CO.sub.2, sulfur and halides in a solid-phase calcium-containing product comprising CaCO.sub.3, CaS and CaX.sub.2; (iii) separating the solid-phase calcium-containing product from an enriched gaseous hydrogen product; and (iv) regenerating the CaO by calcining the solid-phase calcium-containing product at a condition selected from the group consisting of: in the presence of steam, in the presence of CO.sub.2, in the presence of synthesis gas, in the presence of H.sub.2 and O.sub.2, under partial vacuum, and combinations thereof.

Ramkumar, Shwetha; Fan, Liang-Shih

2013-07-30

167

Iron dissolution of dust source materials during simulated acidic processing: the effect of sulfuric, acetic, and oxalic acids.  

PubMed

Atmospheric organic acids potentially display different capacities in iron (Fe) mobilization from atmospheric dust compared with inorganic acids, but few measurements have been made on this comparison. We report here a laboratory investigation of Fe mobilization of coal fly ash, a representative Fe-containing anthropogenic aerosol, and Arizona test dust, a reference source material for mineral dust, in pH 2 sulfuric acid, acetic acid, and oxalic acid, respectively. The effects of pH and solar radiation on Fe dissolution have also been explored. The relative capacities of these three acids in Fe dissolution are in the order of oxalic acid > sulfuric acid > acetic acid. Oxalate forms mononuclear bidentate ligand with surface Fe and promotes Fe dissolution to the greatest extent. Photolysis of Fe-oxalate complexes further enhances Fe dissolution with the concomitant degradation of oxalate. These results suggest that ligand-promoted dissolution of Fe may play a more significant role in mobilizing Fe from atmospheric dust compared with proton-assisted processing. The role of atmospheric organic acids should be taken into account in global-biogeochemical modeling to better access dissolved atmospheric Fe deposition flux at the ocean surface. PMID:23883276

Chen, Haihan; Grassian, Vicki H

2013-09-17

168

Sulfur starvation and chromium tolerance in Scenedesmus acutus: A possible link between metal tolerance and the regulation of sulfur uptake\\/assimilation processes  

Microsoft Academic Search

In a laboratory-selected Cr-tolerant strain of the unicellular green alga Scenedesmus acutus, the capacity to synthesize higher amounts of cysteine (Cys) and reduced glutathione (GSH) than the wild-type was demonstrated to underlie tolerance to Cd and Cr(VI). In photosynthetic organisms sulfate constitutes the main sulfur source for the biosynthesis of GSH and its precursor Cys, hence it was hypothesized that

Gessica Gorbi; Corrado Zanni; Maria Grazia Corradi

2007-01-01

169

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

SciTech Connect

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

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

2005-06-17

170

Sulfur dioxide disposal system  

Microsoft Academic Search

There is disclosed a multi-stage process for reducing sulfur dioxide to sulfur or to hydrogen sulfide whereby a hydrogen-containing gas from a high temperature gasifier is used. In the first stage of the process, the gasifier exit gas is contacted at a minimum temperature of about 1800° F. With recycle gas containing SO2, H2S, COS, mercaptans, and CS2 in order

Kamody

1981-01-01

171

Modifications of sulfur polymer cement (SPC) stabilization and solidification (S/S) process  

SciTech Connect

This paper addresses the effectiveness of using sulfur polymer cement (SPC) as a binder to stabilize/solidify lead-contaminated soils. SPC, which has been used as a construction material because of its excellent resistance to acid and salt environments and its superior water tightness as compared with Portland cement concrete, has recently emerged as a possible alternative binder to stabilize/solidify soils contaminated with hazardous, low-level radioactive and mixed wastes. However, it was found that the use of SPC alone could not satisfactorily stabilize/solidify lead-contaminated soils. Nevertheless, it was shown that additives, such as sodium sulfide or sodium sulfite, could be used to greatly enhance the ability of SPC to react chemically with lead contaminants, and physicochemically to bind these compounds. These enable us significantly to lower the leachability (e.g. from 77.8 mg Pb/l to 1.28 mg Pb/l in EPA TCLP extract) of the SPC-treated wastes to the point where they can be recycled as some form of construction material.

Lin, S.L.; Lai, J.S.; Chian, E.S.K. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering] [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering

1995-12-31

172

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

173

Sulfuric acid in the Venus clouds  

NASA Technical Reports Server (NTRS)

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

Sill, G. T.

1972-01-01

174

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

175

Assessment and investigation of containment materials for the sulfur-iodine thermochemical water-splitting process for hydrogen production. Final report Jul 79Dec 80  

Microsoft Academic Search

This report summarizes the materials investigations conducted at General Atomic to support the on-going process development of the sulfur-iodine thermochemical water-splitting process to produce hydrogen. It presents data from compatibility tests in which candidate construction materials were exposed to chemical and temperature environments simulating the principal process fluids of the water-splitting cycle. The environments were (1) mixtures of HI-H2O-I2 and

P. W. Trester; H. G. Staley

1981-01-01

176

Sequential hydrolysis of hemicellulose and lignin in lignocellulosic biomass by two-stage percolation process using dilute sulfuric acid and ammonium hydroxide  

Microsoft Academic Search

To obtain the total fractionation and pretreatment of the corn stover, two-stage percolation process was investigated. This\\u000a process consists of two steps: use of 0.07 wt% sulfuric acid for hemicellulose recovery in first stage and ARP (ammonia recycled\\u000a percolation) in the following stage for lignin recovery. Among tested conditions, the best conditions of two-stage process\\u000a were as follows: 1st stage;

Tae Hyun Kim

177

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

Microsoft Academic Search

Battelle Pacific Northwest Laboratories has begun to develop a project for removing sulfur compounds from fuel gases at elevated temperature (> 700°C) based on the use of molten mixtures of alkali metal carbonates and calcium carbonate as the active reactants. The sulfur removal capacity of the molten salt mixture may be regenerated by stripping with CO and steam, usually at

G. E. Stegen; K. M. Olson

1980-01-01

178

DSRP, Direct Sulfur Production  

Microsoft Academic Search

Hot-gas desulfurization processes for IGCC and other advanced power applications utilize regenerable mixed-metal oxide sorbents to remove hydrogen sulfide (HS) from raw coal gas. Regeneration of these sorbents produces an off-gas typically containing I to 3 percent sulfur dioxide (SO). Production of elemental sulfur is a highly desirable option for the ultimate disposal of the SO content of this off-gas.

S. K. Gangwal; W. J. McMichael; S. K. Agarwal; B. L. Jang; G. B. Howe; D. H. Chen; J. R. Hopper

1993-01-01

179

Evaluation of Potential Commercial Processes for the Production of Sulfuric Acid from Phosphogypsum.  

National Technical Information Service (NTIS)

Phosphogypsum is a synthetic by-product created during the commercial manufacture of phosphoric acid by the wet process. The synthetic phosphogypsum retains the basic chemical and physical properties of natural gypsum and can be substituted for natural gy...

A. P. Kouloheris

1981-01-01

180

A DESCRIPTION OF THE GLOBAL SULFUR CYCLE AND ITS CONTROLLING PROCESSES IN THE NCAR CCM3  

Microsoft Academic Search

.We examine the balance between processes that contribute to the global and regionaldistributions of sulfate aerosol in the Earth's atmosphere using a set of simulations fromthe NCAR CCM3. The analysis suggests that the seasonal cycle of SO 2 and SO2\\\\Gamma4 arecontrolled by a complex interplay between transport, chemistry and deposition processes.The seasonal cycle of these species are not strongly controlled

P. J. Rasch; M. C. Barth; J. T. Kiehl; S. E. Schwartz; C. M. Benkovitz

2000-01-01

181

Design of a reactive distillation process for ultra-low sulfur diesel production  

Microsoft Academic Search

The analysis of the applicability of the reactive separation concepts to the deep-hydrodesulfurization process has been performed. Through the computation of the reactive residue curve maps a basic conceptual design of a reactive distillation column was obtained. This preliminary design considers two reactive zones, each one packed with a different catalyst, a Ni?Mo based catalyst for the bottom reactive section

Eduardo S. Perez-Cisneros; Salvador A. Granados-Aguilar; Pedro Huitzil-Melendez; Tomas Viveros-Garcia

2002-01-01

182

Integrated UCAP (Union Carbide Alkanolamine Process). a new approach to sulfur recovery  

Microsoft Academic Search

Based on the high SO adsorption capacity, exceptional selectivity for SO over CO, up to 90Vertical Bar3< stage efficiency of adsorption, and strong inhibition of SO oxidation exhibited by aqueous triethanolamine in experimental studies, Union Carbide Corp. has developed the UCAP SO adsorption process, which can be used in desulfurization of refinery streams, flue gas from heaters and boilers, and

C. M. Yon; G. R. Atwood; C. D. Swaim

1979-01-01

183

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

184

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

185

Interfacing the tandem mirror reactor to the sulfur-iodine process for hydrogen production  

SciTech Connect

The blanket is linked to the H/sub 2/SO/sub 4/ vaporization units and SO/sub 3/ decomposition reactor with either sodium or helium. The engineering and safety problems associated with these choices are discussed. This H/sub 2/SO/sub 4/ step uses about 90% of the TMR heat and is best close-coupled to the nuclear island. The rest of the process we propose to be driven by steam and does not require close-coupling. The sodium loop coupling seems to be preferable at this time. We can operate with a blanket around 1200 K and the SO/sub 3/ decomposer around 1050 K. This configuration offers double-barrier protection between Li-Na and the SO/sub 3/ process gases. Heat pipes offer an attractive alternate to provide an additional barrier, added modularity for increased reliability, and tritium concentration and isolation operations with very little thermal penalty.

Galloway, T.R.

1980-06-02

186

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

187

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

NASA Astrophysics Data System (ADS)

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

Murray, David-anthony

188

[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

189

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 resultthe 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

190

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

191

Polyphosphate-Containing Fluid Fertilizers Based on Wet-Process Acid and Wet-Process Acid-Sulfuric Acid Mixtures.  

National Technical Information Service (NTIS)

In the late 1960s and early 1970s, the Tennessee Valley Authority (TVA) developed and patented a pipe-reactor process that used low-conversion superphosphoric acid to produce a 10-34-0 grade liquid fertilizer that contained about 60 to 70% of the total P ...

H. C. Mann

1984-01-01

192

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

PubMed

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

Duan, Baozhong; Huang, Linfang; Chen, Shilin

2012-04-15

193

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

SciTech Connect

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

Towler, G.P.; Lynn, S.

1993-05-01

194

Sulfur cycle in buried evaporites  

NASA Astrophysics Data System (ADS)

Sulfur isotopes are potent indicators of the way in which sulfur behaves chemically during diagenesis. We have studied sulfur isotope ratios (34S/32S) from a number of minerals and compounds across the Permian-Triassic boundary in the Khuff Formation, Abu Dhabi. The ?34S in dissolved marine sulfate increased by 10 from the Late Permian to the Early Triassic. Despite precipitation of gypsum from Permian and Triassic seawater and its subsequent dehydration to anhydrite at depths greater than about 1000 m, the primary marine stratigraphic sulfur isotope variation has been preserved in anhydrite in the Khuff Formation. A combination of biostratigraphic and absolute age data show that this 10 shift occurred over <2 m.y. Gypsum dehydration to anhydrite has not involved significant isotopic fractionation or diagenetic redistribution of material in the subsurface. The sulfur isotope variation across the Permian-Triassic boundary is also present in elemental sulfur and H2S, at depths greater than 4300 m, formed by reaction of anhydrite with hydrocarbons via thermochemical sulfate reduction. This demonstrates that sulfate reduction has not led to isotope fractionation. It also demonstrates that significant mass transfer has not occurred, at least in the vicinity of the Permian-Triassic boundary, even though elemental sulfur and H2S are both fluid phases at depths greater than 4300 m. Thus, despite two major diagenetic processes that converted the sulfur in gypsum into elemental sulfur and H2S by 4300 m burial and the potentially mobile nature of some of the reaction products, the primary differences in sulfur isotopes have been preserved in the rocks and fluids. All reactions occurred in situ; there was no significant sulfur isotope fractionation, and only negligible sulfur was added, subtracted, or moved internally within the system.

Worden, R. H.; Smalley, P. C.; Fallick, A. E.

1997-07-01

195

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

196

Lunar Sulfur.  

National Technical Information Service (NTIS)

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 t...

D. L. Kuck

1991-01-01

197

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

198

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

199

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

Microsoft Academic Search

Sulfur-Iodine cycle is the most promising thermochemical cycle for water splitting to produce hydrogen which can replace the fossil fuels in the future. As a sub-cycle in the thermochemical Sulfur-Iodine water splitting cycle, sulfuric acid (HSO) decomposes into oxygen (O) and sulfur dioxide (SO) which should be separated for the recycle of SO into the sulfuric acid generation reaction (Bunsen

Chang Soo Kim; Gyeong Taek Gong; Kye Sang Yoo; Honggon Kim; Byoung Gwon Lee; Byoung Sung Ahn; Kwang Deog Jung; Ki Yong Lee; Kwang Ho Song

2007-01-01

200

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

201

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

202

Sulfur isotope signatures in gypsiferous sediments of the Estancia and Tularosa Basins as indicators of sulfate sources, hydrological processes, and microbial activity  

NASA Astrophysics Data System (ADS)

In order to reconstruct paleo-environmental conditions for the saline playa lakes of the Rio Grande Rift, we investigated sediment sulfate sources using sulfur isotope compositions of dissolved SO42- ions in modern surface water, groundwater, and SO42- precipitated in the form of gypsum sediments deposited during the Pleistocene and Holocene in the Tularosa and Estancia Basins. The major sulfate sources are Lower and Middle Permian marine evaporites (? 34S of 10.9-14.4), but the diverse physiography of the Tularosa Basin led to a complex drainage system which contributed sulfates from various sources depending on the climate at the time of sedimentation. As inferred from sulfur isotope mass balance constraints, weathering of sulfides of magmatic/hydrothermal and sedimentary origin associated with climate oscillations during Last Glacial Maximum contributed about 35-50% of the sulfates and led to deposition of gypsum with ? 34S values of -1.2 to 2.2 which are substantially lower than Permian evaporates. In the Estancia Basin, microbial sulfate reduction appears to overprint sulfur isotopic signatures that might elucidate past groundwater flows. A Rayleigh distillation model indicates that about 3-18% of sulfates from an inorganic groundwater pool (? 34S of 12.6-13.8) have been metabolized by bacteria and preserved as partially to fully reduced sulfur-bearing minerals species (elemental sulfur, monosulfides, disulfides) with distinctly negative ? 34S values (-42.3 to -20.3) compared to co-existing gypsum (-3.8 to 22.4). For the Tularosa Basin microbial sulfate reduction had negligible effect on ? 34S value of the gypsiferous sediments most likely because of higher annual temperatures (15-33 C) and lower organic carbon content (median 0.09%) in those sediments leading to more efficient oxidation of H 2S and/or smaller rates of sulfate reduction compared to the saline playas of the Estancia Basin (5-28 C; median 0.46% of organic carbon). The White Sands region of the Tularosa Basin is frequently posited as a hydrothermal analogue for Mars. High temperatures of groundwater (33.3 C) and high ? 18O(H 2O) values (1.1) in White Sands, however, are controlled predominantly by seasonal evaporation rather than the modern influx of hydrothermal fluids. Nevertheless, it is possible that some of the geochemical processes in White Sands, such as sulfide weathering during climate oscillations and upwelling of highly mineralized waters, might be considered as valid terrestrial analogues for the sulfate cycle in places such as Meridiani Planum on Mars.

Szynkiewicz, Anna; Moore, Craig H.; Glamoclija, Mihaela; Pratt, Lisa M.

2009-10-01

203

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

SciTech Connect

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

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

1994-01-01

204

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

205

SULFUR POLYMER ENCAPSULATION.  

SciTech Connect

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

KALB, P.

2001-08-22

206

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

Microsoft Academic Search

A series of three pressurized sulfuric acid decomposition tests were performed to (1) obtain data on the fraction of sulfuric acid catalytically converted to sulfur dioxide, oxygen, and water as a function of temperature and pressure, (2) demonstrate real-time measurements of acid conversion for use as process control, (3) obtain multiple measurements of conversion as a function of temperature within

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

2005-01-01

207

[Sulfur isotopic ratios indicating sulfur cycling in slope soils of karst areas].  

PubMed

Sequential extraction methods for soil sulfur were used to determine delta34 S ratios and sulfur contents of total sulfur, organic sulfur, SO4(21) and FeS2 in slope soils of karst areas. In general, FeS2 has the lowest delta34 S ratios, ranging from -6.86% per hundred to -4.229% per hundred, followed in ascending order by SO4(2-) (-2.64% per hundred - -1.34% per hundred), total sulfur (-3.25% per hundred - -1.03% per hundred) and organic sulfur (-1.63% per hundred -0.50% per hundred) in surface soils of profiles, and delta34 S ratios in different sulfur forms all show increasing trend with profiles deepening. Covariations of delta34 S ratios of SO4(2-) and FeS2 with increasing depth are related to SO4(2-) dissimilatory reduction, while the increase in parallel of delta34 S ratios of total sulfur and organic sulfur could be resulted from organic sulfur cycling. delta34 S ratios have been extensively used to indicate sulfur sources, moreover, SO4(2-) dissimilatory reduction and organic sulfur mineralization result in significant sulfur isotopic fractionation, and sulfides oxidation and SO4(2-) assimilation have no isotopic fractionation occurred, the vertical variations of delta34 S ratios in different sulfur forms can therefore be good records for depth-dependant sulfur cycling processes. Furthermore, by comparing depth distributions of sulfur contents and delta34 S ratios in different sulfur forms, it is easily to discuss the migration of SO4(-1) and organic sulfur fractions in soil profiles. PMID:20391712

Zhang, Wei; Liu, Cong-qiang; Li, Xiao-dong; Liu, Tao-ze; Zhang, Li-li

2010-02-01

208

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

NASA Astrophysics Data System (ADS)

Bulk ? 34Srock values, sulfur contents, and magnetic susceptibility were determined for 12 gold-related granitoid intrusions in southwestern New Brunswick, the Canadian Appalachians. The sulfur isotope compositions of sulfide minerals in some of the granitoid samples were also analyzed. This new dataset was used to characterize two distinctive groups of granitoids: (1) a Late Devonian granitic series (GS) and (2) a Late Silurian to Early Devonian granodioritic to monzogranitic series (GMS). The GS rocks have a large range in ? 34S values of -7.1 to +13 with an average of 2.2 5.0 (1?), low bulk-S contents (33 to 7,710 ppm) and low magnetic susceptibility values (<10-4 SI), consistent with reduced ilmenite-series granites. The GMS rocks have a relatively narrower variation in ? 34S values of -4.4 to +7.3 with an average 1.2 2.9 but with larger ranges in bulk-S contents (45 to 11,100 ppm) and high magnetic susceptibility values (>10-3 SI), indicative of oxidized magnetite-series granites. The exceptions for the GMS rocks are the Lake George granodiorite and Tower Hill granite that display reduced characteristics, which may have resulted from interaction of the magmas forming these intrusions with graphite- or organic carbon-bearing sedimentary rocks. The bulk ? 34S values and S contents of the GMS rocks are interpreted in terms of selective assimilation-fractional crystallization (SAFC) processes. Degassing processes may account for the ? 34S values and S contents of some GS rocks. The characteristics of our sulfur isotope and abundance data suggest that mineralizing components S and Au in intrusion-related gold systems are dominantly derived from magmatic sources, although minor contaminants derived from country rocks are evident. In addition, the molar sulfate to sulfide ratio in a granitic rock sample can be calculated from the ? 34Srock value of the whole-rock sample and the ? 34Ssulfide (or ? 34Ssulfate) value of sulfide and/or sulfate mineral in the sample on the basis of S-isotope fractionation and mass balance under the condition of magmatic equilibrium. This may be used to predict the speciation of sulfur in granitic rocks, which can be a potential exploration tool for intrusion-related gold systems.

Yang, Xue-Ming; Lentz, David R.

2010-12-01

209

Production of elemental sulfur and methane from H{sub 2}S and CO{sub 2} derived from a coal desulfurization process. Quaterly technical progress report, October 1, 1996--December 31, 1996  

SciTech Connect

During the thirteenth quarter of the project, the catalytic reaction of H{sub 2}S and CO{sub 2} was carried out around the temperature of 450 to 550{degrees}C to explore the possibility of sulfur removal by solid adsorbents. The experiments combined two unit operations of catalysis and adsorption. A thermogravimetric analyzer (TGA) and a total sulfur analyzer (TSA) were used to investigate the effectiveness of the selected adsorbents used in the H{sub 2}S decomposition process. Three adsorbents, activated carbon, iron sulfide and sulfided Co-Mo-alumina catalyst in the form of powder, were selected for the experiments. The results showed that activated carbon and Co-Mo-Alumina catalyst powder could adsorb up to 9 percent of sulfur in weight. However, the experimental results indicated that there were only trace amount of elemental sulfur produced during the desorption test for the adsorbents.

Jiang, Xueyu; Khang, Soon-Jai; Keener, T.C.

1997-06-01

210

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

NASA Astrophysics Data System (ADS)

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 ?34S sulfide = 4.5), consistent with a 34S-enriched mantle wedge as inferred from arc lavas.

Alt, Jeffrey C.; Shanks, Wayne C.

2006-02-01

211

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

212

Lunar Sulfur Capture System  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

213

On-line sulfur analysis  

SciTech Connect

Field gas processing plants take great care to remove sulfur compounds from the gas coming in through the gathering system to reduce the toxicity and corrosivity of the gas. Then, at key points along the transportation and distribution networks, sulfur-based odorant compounds are added to the gas for safety and to comply with governmental regulations. As a result, a wide range of sulfides may be present in the gas stream, presenting a difficult measurement and separation task for even well-equipped laboratories. Field requirements are even more demanding of time and instrument reliability. Specificity in sulfur compound analysis is becoming more and more important, transcending the traditional ''grains of sulfur per cubit ft'' and, in some instances, regulatory requirements.

Not Available

1988-02-01

214

The sulfur cycle.  

PubMed

Even granting our uncertainties about parts of our model of the sulfur cycle, we can draw some conclusions from it: 1) 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 than matching nature. 2) In industrialized regions he is overwhelming natural processes, and the removal processes are slow enough (several days, at least) so that the increased concentration is marked for hundreds to thousands of kilometers downwind. 3) Our main areas of uncertainty, and ones that demand immediate attention because of their importance to the regional air pollution question, are: (i) the rates of conversion of H(2)S and SO(2) to sulfate particles in polluted as well as unpolluted atmospheres; (ii) the efficiency of removal of sulfur compounds by precipitation in polluted air. And for a better understanding of the global model we need to know: (i) the amount of biogenic H(2)S that enters the atmosphere over the continents and coastal areas; (ii) means of distinguishing man-made and biogenic contributions to excess sulfate in air and precipitation; (iii) the volcanic production of sulfur compounds, and their influence on the particle concentration in the stratosphere; (iv) the large-scale atmospheric circulation patterns that exchange air between stratosphere and troposphere (although absolute amounts of sulfate particles involved are small relative to the lower tropospheric burden); (v) the role of the oceans as sources or sinks for SO(2). PMID:5009760

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

1972-02-11

215

Sulfur trioxide tested for retorting oil shale  

SciTech Connect

Conventional methods for shale oil production rely on combustion of pyrolysis by-products to supply the heat for retorting. Sulfur trioxide is a potential alternative to combustion air for generating the process heat. By-product sulfur from the shale retorting and oil upgrading operations is easily converted to sulfur trioxide. The potential heat generation with sulfur trioxide is greater than with conventional combustion reactions because the sulfur trioxide reacts exothermically not only with the organic carbon but also with carbonate minerals in the shale. This additional heat generation may facilitate retorting of leaner grade shales which produce less by-product gas and residual carbon for use as process fuel. The sulfur trioxide is also more easily concentrated than atmospheric oxygen, so there is less dilution of the retort gas with inert combustion products. Sulfur trioxide is a strong oxidizer and can react exothermically with both the inorganic and organic constituents of oil shale. To avoid oil degradation, the preferred reactions are those with mineral carbonates and water. These reactions can produce sufficient heat to retort oil shale. However, there are a number of deleterious reactions which can degrade the product oil at retorting temperatures. The deleterious reactions are basically direct oxidation of organic carbon. Other deleterious reactions are sulfonation of aromatic hydrocarbons and olefins. Alkanes do not react readily with sulfur trioxide or concentrated sulfuric acid, but the aromatic hydrocarbons and olefins are easily reacted. These sulfonation reactions badly degrade the production oil by increasing the sulfur concentration.

Not Available

1986-06-01

216

Sulfur removal from producer gas. Final report  

Microsoft Academic Search

This is the final report of research accomplished on this project which entails the establishment of the technical and economic feasibility of a hot fuel gas desulfurization process. The process is designed to provide sulfur removal from producer or synthesis gas at high temperature, while conserving gas stream energy, producing a low volume by-product (sulfur) and not requiring large volumes

E. J. Jr. Lutz; D. C. Erickson; M. J. Tullier; H. Reinhold

1984-01-01

217

Sulfur removal from a gas stream  

SciTech Connect

There is disclosed a process for removing sulfur compounds from a gas stream. The process involves passing the gas stream containing the sulfur compounds through a mass of porous material that has deposited upon it a metal oxide, the improvement comprises the continuous or intermittent addition of an oxidizing agent and an amine.

Frech, K.J.; Tazuma, J.J.

1984-03-06

218

Analytical method for the determination of the distribution of sulfur functional groups in American coals. [Contains list of processes with brief description, status and performance  

SciTech Connect

All organic sulfur in mature coals is believed to be bivalent and spread throughout the organic matrix. The most important forms in which organic sulfur appears are dibenzothiophenes, thiophenes, aliphatic sulfides, thiols, and thiophenols. Direct determinations of the abundance of the various organic sulfur groups in coal show that the thiols and thiophenols combined typically range from 10 to 60% of the organic sulfur while aliphatic (plus arylsulfides, which are usually low in concentration) range from 10 to 40%, and thiophenes as calculated by difference range from 10 to 75%, being greater than 30% in most coals. Examples of two coals with a high percentage (77%) of their organic sulfur in aromatic rings, are Illinois No. 6 bituminous coal and Texas lignite (Milam Co.). In the former coal 27% of the organic sulfur is in the form of aliphatic sulfides and 42 and 31% in the form of single ring thiophenes and dibenzothiophenes, respectively. In the lignite about 57% of the organic sulfur was in the form of single thiophene structures and 16% in the form of dibenzothiophenes. Since each organic group reacts at a different rate, the distribution of organic sulfur groups can have a profound effect on the rate of coal desulfurization. For example, more organic sulfur remains in products from coal liquefaction when thiophenic structures predominate in the organic sulfur than when organic sulfides predominate.

Attar, A.

1980-01-01

219

Sulfur as a lunar resource  

NASA Astrophysics Data System (ADS)

Results of a study of seven lava samples from the Apollo 17 landing site are presented. The samples are polished thin sections. Backscattered electron images on an SEM were used to process gray-level spectra to separate the triolite crystals; these were verified with the X-ray spectra. It is found that the quantities of sulfur to be gained by thermal processing are strongly influenced by duration of heating and sample processing; effective processing may require heating with active thermochemical reaction to extract the sulfur as H2S or SO2. The speciation of the sulfur gases evolved might be controlled by manipulation of temperature, total pressure, and partial gas pressures of the extraction environment.

Heiken, G.; Vaniman, D.; Hawkins, H.

220

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

221

Future Sulfur Dioxide Emissions  

Microsoft Academic Search

The importance of sulfur dioxide emissions for climate change is now established, although substantial uncertainties remain. This paper presents projections for future sulfur dioxide emissions using the MiniCAM integrated assessment model. A new income-based parameterization for future sulfur dioxide emissions controls is developed based on purchasing power parity (PPP) income estimates and historical trends related to the implementation of sulfur

Steven J. Smith; Hugh M. Pitcher; Tom M. Wigley

2005-01-01

222

Production of elemental sulfur and methane from H{sub 2}S and CO{sub 2} derived from a coal desulfurization process. First quarterly report, 1996  

SciTech Connect

During the tenth quarter of the project, bench scale experiments were performed to investigate the adsorption ability of different kinds of materials within sulfur vapor environment. Four kinds of adsorbents have been tested. The experimental results indicated that activated carbon was the beet of four adsorbents tested. In addition to the baseline tests, several designs of activated carbon feed system have been tested. Under an inert environment, bench scale experiments were performed to investigate the characteristics and efficiency of activated carbon passing through the Co-Mo-Alumina catalyst bed. The results showed that activated carbon powder could easily be transported through the catalytic bed. The adsorption process may be applicable to promote conversion of H{sub 2}S in the H{sub 2}S and CO{sub 2} rea system.

Gong, Sung-Yong; Jiang, Xueyu; Khang, Soon-Jai; Keener, T.C.

1997-09-01

223

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, July-September 1982. [Thermometric titration of polysulfides with p-hydroxymercuribenzoate  

SciTech Connect

Task 1. Methods development for the speciation of the polysulfides. The investigation of the thermodynamics of competing reactions, which may interfere in the thermometric titration of polysulfides with the reagent p-hydroxymercuribenzoate, was completed. The reactions are described by the general equation, /sup -/OOC phi HgOH + Nu/sup z/ = /sup -/OOC phi HgNu/sup z+1/ + OH/sup -/ where Nu is a nucleophile and z is less than or equal to O denotes a charge number. Values of log K and ..delta..H/sub r//sup 0/' are reported for the following nucleophiles: S/sup -2/, S/sub x//sup -2/, CN/sup -/, S/sub 2/O/sub 3//sup -2/, I/sup -/, SO/sub 3//sup -2/, NH/sub 3/, SCN/sup -/, all of which are significant contaminants in coal conversion process streams. Electroreduction of polysulfides to HS/sup -/ at the dropping mercury electrode has been found to yield diffusion controlled polarographic limiting currents. These are amenable to the determination of polysulfidic sulfur in a range of concentrations between 5 x 10/sup -5/ M and 3 x 10/sup -3/ M. Task 2. Methods development for the speciation of dithionite and polysulfides. Classical chemical methods of polythionate analysis will be the starting point in the development of new thermochemical approaches for the speciation of the moieties S/sub 2/O/sub 6//sup -2/, S/sub 3/O/sub 6//sup -2/, S/sub 4/O/sub 6//sup -2/, S/sub 5/O/sub 6//sup -2/, and S/sub 6/O/sub 6//sup -2/. Task 3. Total accounting of the sulfur balance in representative samples of synfuel process streams. Arrangements have been completed for the shipment of the first set of representative specimens. Precautions will be taken to prevent alternations en route. 12 figures, 2 tables.

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

1982-10-01

224

Sonoluminescence of elementary sulfur melt  

NASA Astrophysics Data System (ADS)

The sonoluminescence of liquid sulfur has been observed for temperatures of 120-180C. The sonoluminescence intensity of the sulfur melt is 109 photons/s at 120C. As the temperature increases, the luminescence intensity decreases nonmonotonically, a maximum is observed at 160-175C, and cavitation and luminescence cease at 180C. The dependence obtained correlates with the temperature dependence of the viscosity of the sulfur melt. The sonoluminescence spectrum obtained with a resolution of 10 nm for 130-150C contains one band with ?max = 560 nm, the emitter of which is likely an (S+)* ion. When the melt is saturated with argon, the sonoluminescence intensity increases by an order of magnitude; in this case, the spectral band shape changes only slightly. The results confirm the electric theory of multibubble sonoluminescence. In the process of the sonolysis of the sulfur melt, biradical fragments are formed in cavitation bubbles consisting of sulfur molecules, which initially have the form of cyclooctasulfur S8. These fragments can enter into the melts and can be involved in various chemical reactions. This circumstance makes it possible to recommend ultrasonic activation for reactions of sulfurization of hydrocarbons.

Abdrakhmanov, A. M.; Sharipov, G. L.; Rusakov, I. V.; Akhmetova, V. R.; Bulgakov, R. G.

2007-06-01

225

40 CFR 60.642 - Standards for sulfur dioxide.  

Code of Federal Regulations, 2010 CFR

...Performance for Onshore Natural Gas Processing: Sec. 60.642...the sulfur content of the acid gas (Y) of the affected facility...the sulfur content of the acid gas (Y) of the affected facility. [[Page 650

2009-07-01

226

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

227

Technoeconomic analysis of the dilute sulfuric acid and enzymatic hydrolysis process for the conversion of corn stover to ethanol  

Microsoft Academic Search

Technoeconomic analysis has been used to guide the research and development of lignocellulosic biofuels production processes\\u000a for over two decades. Such analysis has served to identify the key technical barriers for these conversion processes so that\\u000a research can be targeted most effectively on the pertinent challenges. The tools and methodology used to develop conceptual\\u000a conversion processes and analyze their economics

Andy Aden; Thomas Foust

2009-01-01

228

Process for Cleaning and Removal of Sulfur Compounds from Low Btu Fuel Gases. Interim Report, January--March 1976.  

National Technical Information Service (NTIS)

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 s...

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

1976-01-01

229

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

230

Solar production of hydrogen using the sulfur-iodine thermochemical water-splitting cycle. Final report  

Microsoft Academic Search

A sulfur-sulfuric acid energy storage system is proposed for the General Atomic Company (GA) sulfur-iodine thermochemical water-splitting cycle. In this concept sulfur is burned to sulfur dioxide in air, generating the energy needed for the hydrogen production process at night and during periods of low insolation. The product of the sulfur burning reaction also provides one of the components (SO)

J. H. Norman; G. Besenbruch; L. Brown

1982-01-01

231

Thiophenic Sulfur Compounds Released During Coal Pyrolysis.  

PubMed

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

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

2013-06-01

232

Thiophenic Sulfur Compounds Released During Coal Pyrolysis  

PubMed Central

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

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

2013-01-01

233

Sulfuric acid poisoning  

MedlinePLUS

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

234

H2-MHR Conceptual Designs Based on the Sulfur-Iodine Process and Hgh-temperature Electrolysis  

SciTech Connect

For electricity and hydrogen production, the advanced reactor technology receiving the most international interest is a modular, passively safe version of the high-temperature, helium-cooled reactor referred to in the USA as the Modular Helium Reactor (MHR). Because of its ability to produce high-temperature helium, the MHR is well suited for a number of process-heat applications, including hydrogen production. Two hydrogen-production technologies have emerged as leading candidates for coupling to the MHR: (1) thermochemical water splitting using the SulphurIodine (SI) process and (2) High-Temperature Electrolysis (HTE). In this paper, we provide an update on conceptual designs being developed for coupling the MHR to the SI process and HTE. These concepts are referred to as the SI-based H2-MHR and the HTE-based H2-MHR, respectively.

Matt Richards; Arkal Shenoy; Ken Schultz; Lloyd Brown; E. A. Harvego; Michael McKellar; Jean-Phillippe Coupey; S. M. Moshin Reza; Futoshi Okamoto; Norihiko Handa

2006-03-01

235

Synthesis of sulfur nanoparticles in aqueous surfactant solutions  

Microsoft Academic Search

Sulfur is a widely used element in different applications such as fertilizers, pharmaceuticals, rubber, fiber industries, bioleaching processes, anti microbial agents, insecticides, and fumigants, etc. Nanosize sulfur particles are useful for pharmaceuticals, modification of carbon nano tubes, and synthesis of nano composites for lithium batteries. In this study we report a surfactant assisted route for the synthesis of sulfur nanoparticles

Rajib Ghosh Chaudhuri; Santanu Paria

2010-01-01

236

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...

237

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

238

Analyze trace sulfur compounds in hydrocarbon gas streams  

Microsoft Academic Search

Measuring trace sulfur compounds in fuel gases has been an industry requirement for many years and now plays a role in a variety of processing areas. One such area involves controlling hydrogen sulfide (HS) and other sulfur compounds in natural gas and fuel gas to prevent corrosion of pipelines and other equipment. Further, using sulfur compounds as odorants makes natural

M. Anderson; R. C. Dimmer

1997-01-01

239

Atmospheric Atomic Sulfur Ion Reactions.  

National Technical Information Service (NTIS)

The apparent observation of atomic sulfur ions below 86 km in the ionosphere stimulates an interest in their possible production and loss processes. Toward this end we have measured the following reactions at 300K: S(+) + NO goes to NO(+) + S, for k = 4.2...

F. C. Fehsenfeld E. E. Ferguson

1972-01-01

240

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

Microsoft Academic Search

Progress on development of the Solid Supported Molten Salt (SSMS) Process is reported. Absorption and regeneration reaction rate data were obtained using a gravimetric technique. Durability and salt impregnation tests were also performed on a number of commercially available and custom fabricated ceramic samples. Results to date indicate that lithium aluminate, magnesium oxide, and zirconium oxide may all be suitable

Stegen

1980-01-01

241

The effect of heavy aromatic sulfur compounds on sulfur in cracked naphtha  

Microsoft Academic Search

The scope of the present study was to elucidate the effect of heavy sulfur compounds, commonly found in the gas oils, on the percentage of sulfur in gasoline range during the Fluid Catalytic Cracking (FCC) process. Five model sulfur compounds commonly found in the gas oils were studied: benzothiophene, 2-methyl-benzothiophene, 3-decyl-thiophene, dibenzothiophene and 4,6-dimethyl-dibenzothiophene. In order to maintain a realistic

J. A. Valla; E. Mouriki; A. A. Lappas; I. A. Vasalos

2007-01-01

242

SULFUR POLYMER ENCAPSULATION  

Microsoft Academic Search

Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature

2001-01-01

243

Continuous Crystallization of Sulfur Formed by the Liquid-Phase Reaction of Hydrogen Sulfide and Sulfur Dioxide.  

National Technical Information Service (NTIS)

The crystallization of elemental sulfur is a unit operation in a process being developed to remove hydrogen sulfide from industrial gas streams. The sulfur is formed by the irreversible, liquid-phase reaction of hydrogen sulfide (H(sub 2)S) and sulfur dio...

C. A. Stevens S. Lynn

1989-01-01

244

The continuous crystallization of sulfur formed by the liquid-phase reaction of hydrogen sulfide and sulfur dioxide  

Microsoft Academic Search

The crystallization of elemental sulfur is a unit operation in a process being developed to remove hydrogen sulfide from industrial gas streams. The sulfur is formed by the irreversible, liquid-phase reaction of hydrogen sulfide (HS) and sulfur dioxide (SO). Low-temperature sulfur solubility data in triethylene glycol dimethyl ether (Triglyme) and diethylene glycol methyl ether (DGM) were collected. The effects of

C. A. Stevens; S. Lynn

1989-01-01

245

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, January-March 1982. [P-hydroxymercuribenzoate (HMB) titrant  

SciTech Connect

This is the second quarterly report on work performed under contract renewed on September 30, 1981. Task 1. Methods development for the speciation of the polysulfides. Polysulfides were found to rearrange to longer average chain lengths during titration with p-hydroxymercuribenzoate (HMB). Such rearrangement was relatively rapid and reproducible for a given pH, producing tetrasulfide at pH14. The reaction of cyanide and HMB was investigated, yielding approximate thermodynamic assignments. Task 2. Methods development for the speciation of dithionite and polysulfides. The literature on the voltammetry of the moieties S/sub 2/O/sub 4//sup -2/, S/sub 2/O/sub 6//sup -2/, S/sub 3/O/sub 6//sup -2/, S/sub 4/O/sub 6//sup -2/, S/sub 5/O/sub 6//sup -2/ is reviewed. These moieties exhibit different half-wave potentials, on the basis of which speciation might be feasible. Analytically viable diffusion controlled currents have also been reported for a majority of the moieties. Carefully controlled conditions must be maintained (buffers, supporting electrolytes) in order to suppress anomalies (maxima, etc.) and obtain well defined limiting current domains. Task 3. Total accounting of the sulfur balance in representative samples of synfuel process streams. Work is scheduled to begin on April 1, 1982.

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

1982-04-01

246

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

247

Sulfur tolerant anode materials  

SciTech Connect

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

Not Available

1987-02-01

248

CATALYST EVALUATION FOR A SULFUR DIOXIDE-DEPOLARIZED ELECTROLYZER  

SciTech Connect

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

Hobbs, D; Hector Colon-Mercado, H

2007-01-31

249

Sulfur rate control system  

SciTech Connect

A sulfur rate control system is described for substantially optimizing particulate removal performance of an electrostatic precipitator in fluid communication with a flue carrying combustion products of a fossil fuel, comprising: an electrostatic precipitator having an inlet for receiving a flue gas: means for injecting sulfur trioxide into a flue for mixing with said flue gas at a location preceding entry of said flue gas into said electrostatic precipitator, said injection of sulfur trioxide being varied responsive to a proportional control signal; and, control means coupled to both said flue and said sulfur trioxide injection means for generating said proportional control signal, said control means including (1) means for measuring a sulfur dioxide concentration quantity in said flue gas at a location preceding said sulfur trioxide injection means, (2) means for measuring a flow rate of particulates in said flue gas at a location preceding said sulfur trioxide injection means, and (3) a controller for calculating a ratio between said sulfur dioxide concentration quantity and said flow rate of particulates, said ratio calculating controller having a first input coupled to said sulfur dioxide measuring means and a second input coupled to said particulate flow rate measuring means for generating said proportional control signal in proportion to a difference between a predetermined value and said ratio between said sulfur dioxide concentration quantity and said flow rate of particulates, said ratio controller having an output coupled to said sulfur trioxide injection means for maximizing particulate removal efficiency of said electrostatic precipitator.

Bell, T.A.; Mullendore, M.G.; Kleinfeldt, T.E.; Walker, H.G. Jr.

1993-07-20

250

A study on carbothermal reduction of sulfur dioxide to elemental sulfur using oilsands fluid coke.  

PubMed

Experiments and reaction equilibrium calculations were carried out for the SO2 gas and oilsands fluid coke system. The goal was to develop a coke-based sulfur-producing flue gas desulfurization (SP-FGD) process that removes SO2 from flue gases and converts it into elemental sulfur. The conversion of SO2 to elemental sulfur proceeded efficiently at temperatures higher than 600 degrees C, and the sulfur yield reached a maximum (> 95%) at about 700 degrees C. An increase of temperature beyond 700 degrees C enhanced the reduction of product elemental sulfur, resulting in the formation of reduced sulfur species (COS and CS2), which lowered the sulfur yield at 900 degrees C to 90%. Although equilibrium calculations suggest that a lower temperature favors the conversion of SO2 as well as the yield of elemental sulfur, experiments showed no formation of elemental sulfur at 600 degrees C and below, likely due to hindered kinetics. Faster reduction of SO2 was observed at a higher temperature in the range of 700-1000 degrees C. A complete conversion of SO2 was achieved in about 8 s at 700 degrees C. Prolonging the product gas--coke contact, the yield of elemental sulfur decreased due to the formation of COS and CS2 while the SO2 conversion remained complete. Equilibrium calculations suggest that the ultimate yield of elemental sulfur maximizes at the C/SO2 ratio of 1, which represents the stoichiometry of SO2 + C-->CO2 + S. For the C/SO2 ratio < 1, equilibrium calculations predict elemental sulfur and CO2 being major products, suggesting that SO2 + C-->CO2 + S is the predominant reaction if SO2 is in excess. Experiments revealed that elemental sulfur and CO2 were only major products if the conversion of SO2 was incomplete, which is in agreement with the result of the equilibrium modeling. PMID:11349295

Bejarano, C A; Jia, C Q; Chung, K H

2001-02-15

251

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

252

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

SciTech Connect

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

Kalb, Paul

2007-05-31

253

Low-Sulfur Fuel Oil from Coal.  

National Technical Information Service (NTIS)

A high-sulfur bituminous coal suspended in coal tar was hydrodesulfurized by continuous processing through a fixed bed of pelletized cobalt molybdate on alumina catalyst, under conditions of highly turbulent flow of hydrogen to prevent obstruction of the ...

P. M. Yavorsky S. Akhtar S. Friedman

1971-01-01

254

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

255

Tribological behavior of near-frictionless carbon coatings in high- and low-sulfur diesel fuels  

Microsoft Academic Search

The sulfur content in diesel fuel has a significant effect on diesel engine emissions, which are currently subject to environmental regulations. It has been observed that engine particulate and gaseous emissions are directly proportional to fuel sulfur content. With the introduction of low-sulfur fuels, significant reductions in emissions are expected. The process of sulfur reduction in petroleum-based diesel fuels also

M. F. Alzoubi; O. O. Ajayi; O. L. Eryilmaz; O. Ozturk; A. Erdemir; G. Fenske

2000-01-01

256

Phase Equilibria for Separation of Organic Sulfur Compounds for Cleaner Fuels  

Microsoft Academic Search

The infinite dilution activity coefficients (??) of sulfur compounds in hydrocarbons are very important in the reliable design of sulfur removal processes producing cleaner gasoline. We determined 23 ?? of sulfur compounds from vapor-liquid equilibrium (VLE) binary systems measurements with recirculation still and 7 infinite dilution activity coefficients of systems containing different sulfur compounds in selected hydrocarbons with comparative ebulliometers.

Erlin Sapei; Piia Haimi; Anna Zaytseva; Petri Uusi-Kyyny; Kari I. Keskinen; Juhani Aittamaa

257

Effect of Water Transport on the Production of Hydrogen and Sulfuric Acid in a PEM Electrolyzer  

Microsoft Academic Search

The thermochemical cycle involving the interconversion between sulfur dioxide and sulfuric acid is a promising method for efficient, large-scale production of hydrogen. A key step in the process is the oxidation of sulfur dioxide to sulfuric acid in an electrolyzer. Gaseous SO2 fed to a proton exchange membrane PEM electrolyzer was previously investigated and was shown to be a promising

John A. Staser; John W. Weidner

2009-01-01

258

Io - Geochemistry of sulfur  

NASA Astrophysics Data System (ADS)

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.

1982-04-01

259

H2S(g) removal using a modified, low-ph liquid redox sulfur recovery (LRSR) process with electrochemical regeneration of the Fe catalyst couple.  

PubMed

A modified pH 1.0 liquid redox sulfur recovery (LRSR) process, based on reactive absorption of H(2)S((g)) in an acidic (pH 1.0) iron solution ([Fe(III)] = 9-8 g L(-1), [Fe(II)] = 1-2 g L(-1)) and electrochemical regeneration of the Fe(III)/Fe(II) catalyst couple, is introduced. Fe(II) was oxidized in a flow-through electrolytic cell by Cl(2(aq)) formed on a Ti/RuO(2) anode. pH 1.0 was applied to retard the potential precipitation of predominantly jarosite group Fe(III) species. At pH 1.0, the presence of chloride ions at [Cl(-)] = 30 g L(-1) allows for both efficient (indirect) electrochemical oxidation of Fe(II) and efficient H(2)S((g)) reactive absorption. The latter observation was hypothesized to be associated with higher concentrations of Fe(III)-Cl complexes that are more highly reactive toward H(2)S((aq)) than are free Fe(III) ions and Fe-SO(4) complexes that otherwise dominate pH 1.0 Fe(III) solutions in the absence of a significant Cl(-) concentration. At the described operational conditions the rate of Fe(II) oxidation in the experimental system was 0.793 kg Fe h(-1) per m(2) anode surface area, at a current efficiency of 58%. Electricity cost within the electrochemical step was approximated at $0.9 per kg H(2)S((g)) removed. PMID:19924962

Gendel, Youri; Levi, No'omi; Lahav, Ori

2009-11-01

260

Relationship between corrosion and the biological sulfur cycle: A review  

SciTech Connect

Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numbers and types of sulfur-related organisms and the probability or rate of corrosion, Determination of specific mechanisms for corrosion caused by microbiologically mediated oxidation and reduction of sulfur and sulfur compounds is complicated by the variety of potential metabolic-energy sources and by-products; the coexistence of reduced and oxidized sulfur species; competing reactions with inorganic and organic compounds; and the versatility and adaptability of microorganisms in biofilms. The microbial ecology of sulfur-rich environments is poorly understood because of the association of aerobes and anaerobes and the mutualism or succession of heterotrophs to autotrophs. The physical scale over which the sulfur cycle influences corrosion varies with the environment. The complete sulfur cycle of oxidation and reduction reactions can take place in macroenvironments, including sewers and polluted harbors, or within the microenvironment of biofilms. In this review, reactions of sulfur and sulfur compounds resulting in corrosion were discussed in the context of environmental processes important to corrosion.

Little, B.J.; Ray, R.I.; Pope, R.K.

2000-04-01

261

Oxidation of sulfur by oxygen in presence of hydrogen chloride  

SciTech Connect

It is believed that sulfur trioxide is formed first during the combustion of sulfur, because the change of Gibbs energy during its formation has a larger negative value than its change during formation of sulfur dioxide. Subsequently the SO/sub 3/ decomposes under the influence of high temperature, or interacts with sulfur to form sulfur dioxide. In order to prevent these undesirable processes it was recommended to cool the combustion gases or to introduce a substance binding sulfur trioxide into the reaction mixture, thereby preventing its interaction with sulfur. Hydrochloric acid, which can form chlorosulfonic acid with sulfur trioxide, was used for this purpose. We accordingly examined the thermodynamics and studied the kinetics of sulfur oxidation by oxygen in presence of HCl in wide ranges of temperature, component concentrations, and reaction time. The influence of HCl on the yield of sulfur trioxide during oxidation of sulfur by oxygen is not determined by simple interaction of SO/sub 3/ with HCl, but involves formation of CL/sub 2/, which oxidizes the SO/sub 2/ formed to sulfonyl chloride at the stage of cooling of the reaction mixture; the sulfonyl chloride is then hydrolyzed by water to H/sub 2/SO/sub 4/ and HCl. In order to raise the SO/sub 3/ yield, oxidation of sulfur in presence of HCl must be conducted in presence of a catalyst active in the reaction of CL/sub 2/ formation.

Filatov, Yu.N.; Igin, V.V.; Varshavskaya, L.M.; Ryzhkova, A.A.

1988-11-20

262

The sulfur cycle and clouds of Venus  

NASA Astrophysics Data System (ADS)

The clouds of Venus play a central role in governing its meteorology and climate. These clouds contain concentrated sulfuric acid and an ultraviolet absorbing material which is probably elemental sulfur; their existence depends on the working of complex chemical cycles on the planet. In this paper, the overall chemical cycle responsible for the maintenance of significant amounts of the lithophilic element sulfur in the atmosphere, and the photochemical and thermochemical reactions involved in formation and destruction of the cloud particles themselves are elucidated. The susceptibility of these processes to change (e.g., due to episodic volcanism) with concomitant feedacks to the Venusian climate is emphasized.

Prinn, R. G.

263

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

264

ENGINEERING/ECONOMIC ANALYSES OF COAL PREPARATION WITH SO2 CLEANUP PROCESSES FOR KEEPING HIGHER SULFUR COALS IN THE ENERGY MARKET  

EPA Science Inventory

For purposes of this study, higher sulfur coals from the Northern Appalachian and Eastern Interior Regions were selected since they have been shown to have reasonable physical cleaning potential. Then, possible users of these coals in the electric power generating industry were e...

265

Generation of Sulfur-rich, Sulfur-undersaturated Basaltic Melts in Oxidized Arc Sources.  

NASA Astrophysics Data System (ADS)

Although sulfur is a minor element in the Earth, it has a disproportionate impact because it commonly occurs as sulfide. Sulfides largely control the behavior of chalcophile (e.g., Cu, Ni) and highly siderophile elements (Ru, Rh, Pd, Re, Os, Ir, Pt, and Au) that are of interest because either they are economically important or because they provide valuable information about geochemical processes. Island arc basalts are more oxidized than basalts from other tectonic settings and therefore, in these settings, sulfur maybe present not as sulfide but as sulfate. In addition to the impact on the behavior of chalcophile and siderophile elements, sulfur speciation as sulfate may have a role on the occurrence of sulfur-rich explosive volcanism, which has been linked to significant short-term variations in global climate. However, little is known about the range in oxygen fugacity for the transition from solubility as sulfide to solubility as sulfate. We used experimental data on the solubility of sulfur in basaltic melts saturated with either sulfide or sulfate at different oxygen fugacities to model this transition. Our model shows that the ten-fold increase in the solubility of sulfur (from 0.14 wt.% to 1.5 wt.%) observed experimentally occurs at oxygen fugacities between FMQ+1 and FMQ+2, conditions under which many arc magmas are thought to be generated. The increase in the solubility of sulfur with increasing oxygen fugacity implies that in oxidized arc sources very low degrees of partial melting are sufficient to generate basaltic melts that are simultaneously sulfur-rich and sulfur-undersaturated. In the absence of sulfides, oxides and metallic alloys may influence the behavior of some (but not all) the highly siderophile elements whereas the chalcophile and some siderophile elements become incompatible. As a consequence, melting of oxidized sources in which sulfides are not stable would favor incorporation of metals such as Cu, Ni, Au and Pd in the melts and increase the ability of those melts to generate Au-rich and Pd-rich ore deposits. In addition, partitioning of sulfur into a hydrous phase upon decompression and mixing of a sulfur-rich basaltic melt with water-rich felsic magmas provides a feasible mechanism to explain the sulfur-rich degassing observed in some volcanoes. We emphasize the importance of accounting for the oxidation state of sulfur when modeling magmatic processes in which sulfur is a key component, specially in arc magmas where sulfur is likely to be present both as sulfide and sulfate.

Jugo, P. J.; Luth, R. W.; Richards, J. P.

2003-12-01

266

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

267

Regional river sulfur runoff  

SciTech Connect

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

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

1985-01-20

268

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

269

The fate of sulfur during rapid pyrolysis of scrap tires.  

PubMed

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

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

2014-02-01

270

Sulfur Recovery in a Coal Gasification Plant.  

National Technical Information Service (NTIS)

For the western coal feed, the combination of a non-selective Selexol process for acid gas removal, FMC Double Alkali process for flue gas cleanup, and a Stretford process for sulfur recovery, was the most economical among the cases studied. For the easte...

W. S. Chia F. A. Todd

1978-01-01

271

Sulfur-assisted synthesis of nitride nanocrystals.  

PubMed

A series of nitrides (TiN, ZrN, BN, AlN) were prepared by using the corresponding elements (Ti, Zr, B, Al), NaN(3) and sulfur as starting materials in a stainless steel autoclave at 250 degrees C. Sulfur was used to facilitate the exothermic reaction between NaN(3) and sulfur (at 250 degrees C) and the final formation of nitrides. The treatment temperature affected the growth of the nitride crystals, for example, diversified morphologies of TiN nanocrystals were formed in different temperature ranges: grain and truncated octahedron (250 degrees C), octahedron (>300 degrees C), and dendrite (>400 degrees C). Through similar processes, other nitrides (for example, TiN, AlN, Si(3)N(4)) could also be produced by employing NaNH(2) and additives (such as iodine or N-aminothiourea instead of sulfur) in low temperatures. PMID:20200712

Yang, Lishan; Yu, Hongxiao; Xu, Liqiang; Ma, Qiang; Qian, Yitai

2010-03-21

272

Transposon Mutagenesis in Purple Sulfur Photosynthetic Bacteria: Identification of hypF, Encoding a Protein Capable of Processing [NiFe] Hydrogenases in , , and Subdivisions of the Proteobacteria  

Microsoft Academic Search

A random transposon-based mutagenesis system was optimized for the purple sulfur phototrophic bacte- rium Thiocapsa roseopersicina BBS. Screening for hydrogenase-deficient phenotypes resulted in the isolation of six independent mutants in a mini-Tn5 library. One of the mutations was in a gene showing high amino acid sequence similarity to HypF proteins in other organisms. Inactivation of hydrogen uptake activity in the

BARNA FODOR; GABOR RAKHELY; AKOS T. KOVACS; KORNEL L. KOVACS

2001-01-01

273

Effect of solution flow rate and direction on copper electrodeposition process from sulfuric acid electrolyte on porous electrode with high electric conductivity  

Microsoft Academic Search

The effect of solution flow direction and rate on the dynamics of copper electrodeposition onto a premetallized coal-graphite\\u000a VINN-250 material from a dilute copper sulfate sulfuric acid solution is experimentally studied in the direct-flow mode. A\\u000a light effect of solution supply on the copper deposit final mass for high and low solution flow rates is found, while the\\u000a effect of

A. Zh. Medvedev; A. F. Zherebilov; A. I. Masliiy; N. P. Poddubnyi

2008-01-01

274

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

275

Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction  

SciTech Connect

A pre-combustion coal desulfurization process at 120{degree}C using perchloroethylene (PCE) to remove up to 70% of the organic sulfur has been developed by the Midwest Ore Processing Co. (MWOPC). However, this process has not yet proven to be as successful with Illinois coals as it has for Ohio and Indiana coals. The organic sulfur removal has been achieved only with highly oxidized Illinois coals containing high sulfatic sulfur. A logical explanation for this observation is vital to successful process optimization for the use of Illinois coals. In addition, the high levels of organic sulfur removals observed by the MWOPC may be due to certain errors involved in the ASTM data interpretation; this needs verification. For example, elemental sulfur extracted by the PCE may be derived from pyrite oxidation during coal pre-oxidation, but it may be interpreted as organic sulfur removed by the PCE using ASTM analysis. The goals of this research are: (1) to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization process reported by the MWOPC, (2) to verify the forms-of-sulfur determination using the ASTM method for the PCE process evaluation, and (3) to determine the suitability of Illinois coals for use in the PCE desulfurization process. This project involves the Illinois State Geological Survey (ISGS), Eastern Illinois University (EIU), the University of Illinois-Urbana/Champaign (UI-UC), and the University of Kentucky, Lexington (UK). This is the first year of a two-year project.

Chou, M.I.M.

1991-01-01

276

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

SciTech Connect

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

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

2007-07-01

277

Kinetics of decomposition of manganese slimes by sulfur dioxide  

SciTech Connect

Lean manganese ores, and slimes obtained during mechanical beneficiation of Chiatura manganese ores, have been treated by the sulfite process, by saturation of suspensions with sulfur dioxide. The kinetics of saturation of the suspensions with sulfur dioxide, and transfer of manganese into solution was studied. Manganese was leached out by passing sulfur dioxide through the slime suspension. The sulfur dioxide dissolved in water to form the weakly dissociated sulfurous acid in equilibrium with its anhydrides. The leaching was conducted without access of air at room temperature. An equation for determination of the rate of sulfur dioxide adsorption by a manganese-containing slurry and for calculation of the degree of manganese extraction into solution was developed from the experimental results. The reaction order and the control regime of the processes were determined.

Dzhaparidze, P.I.; Kelbakiani, N.V.

1982-02-20

278

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

279

Impact of the preparation conditions in the sulfur distribution of a new sulfurized porous adsorbent  

SciTech Connect

Fibrous natural silicates (sepiolite), instead of more conventional active carbon, have been sulfurized to be used as remover agents of mercury vapors from contaminated industrial waste gases. The Claus reaction, 2nH[sub 2]S + nSO[sub 2] [r arrow] (3n/x)S[sub x] + 2nH[sub 2]O, at low temperature (<400 K) and reactant concentration (2--3% molar) has been used as the sulfur source, thus being an additional way of eliminating SO[sub 2] from metallurgical processes and urban areas. The process has been carried out in a fluidized bed reactor of the semicontinuous type, and various homogeneous materials with sulfur contents in the range 3--40% S were generated. Sulfur condensation results in catalyst deactivation but, prior to its stabilization as monoclinic sulfur, also acts as cocatalyst of the reaction contributing to its overall kinetics. A study of the operating conditions, temperature, reactant concentration, and textural properties of the solid on the yield of sulfur deposited has been made. Different pore-plugging mechanisms have been applied, and from them, the influence of temperature in sulfur distribution has been concluded. In this paper, TA, N[sub 2] adsorption at 77 K, and mercury-intrusion porosimetry were used to characterize the resulting adsorbents.

Guijarro, M.I.; Mendioroz, S. (CSIC, Madrid (Spain). Inst. Catalisis y Petroleoquimica); Munoz, V. (U.N.E.D., Madrid (Spain). Dept. de Quimica Inorganica y Quimica Tecnica)

1994-02-01

280

Engineering design of a thermochemical water-splitting cycle. Final report. [Sulfuric acid--sulfur oxide--sulfide cycle  

Microsoft Academic Search

In consultation with Los Alamos Scientific Laboratory, the LASL baseline sulfuric acid-sulfur-oxide-sulfide cycle for thermochemical hydrogen production was selected for preliminary engineering design. Using LASL data, or values estimated in collaboration with LASL where data were incomplete, process conditions for all primary reactions were established. Conceptual solutions for separation and recycle processes were developed and combined with the primary reactions

J. De Graaf; L. Halvers; J. Porter; J. Russell

1976-01-01

281

Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Final technical report, 1 September, 1992--31 August, 1993  

SciTech Connect

The Midwest Ore Processing Co. (MWOPC) has reported a precombustion coal desulfurization process using perchloroethylene (PCE) at 120 C to remove up to 70% of the organic sulfur. The purposes of this research were to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization and to verify the ASTM forms-of-sulfur determination for evaluation of the process. An additional goal was to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. A laboratory scale operation of the MWOPC PCE desulfurization process was demonstrated, and a dechlorination procedure to remove excess PCE from the PCE-treated coal was developed. The authors have determined that PCE desulfurization removed mainly elemental sulfur from coal. The higher the level of coal oxidization, the larger the amount of elemental sulfur that is removed by PCE extraction. The increased elemental sulfur during short-term preoxidation is found to be pH dependent and is attributed to coal pyrite oxidation under acidic (pH < 2) conditions. The non-ASTM sulfur analyses confirmed the hypothesis that the elemental sulfur produced by oxidation of pyrite complicates the interpretation of analytical data for PCE process evaluations when only the ASTM forms-of-sulfur is used. When the ASTM method is used alone, the elemental sulfur removed during PCE desulfurization is counted as organic sulfur. A study using model compounds suggests that mild preoxidation treatment of coal described by MWOPC for removal of organic sulfur does not produce enough oxidized organic sulfur to account for the amounts of sulfur removal reported. Furthermore, when oxidation of coal-like organosulfur compounds does occur, the products are inconsistent with production of elemental sulfur, the product reported by MWOPC. Overall, it is demonstrated that the PCE process is not suitable for organic sulfur removal.

Chou, M.I.M.; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Frost, J.K. [Illinois State Geological Survey, Champaign, IL (United States); Buchanan, D.H. [Eastern Illinois Univ., Charleston, IL (United States); Stucki, J.W. [Univ. of Illinois, Urbana, IL (United States); Huffman, G.P.; Huggins, F.E. [Univ. of Kentucky, Lexington, KY (United States)

1993-12-31

282

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

NASA Astrophysics Data System (ADS)

We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H 2SO 4), sulfuric acid monohydrate (H 2SO 4H 2O), and sulfuric acid tetrahydrate (H 2SO 44H 2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H 2O, SO 2, (S 2O 3) x, H 3O +, HSO4-, and SO42-. At high radiation doses, we find that H 2SO 4 molecules are destroyed completely and that H 2SO 4H 2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H 2SO 4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H 2SO 4 or H 2SO 4H 2O, the loss of H 2SO 44H 2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa's surface, we speculate that the variations in SO 2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

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

2011-09-01

283

Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and Its Relevance to Europa  

NASA Technical Reports Server (NTRS)

We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4 H2O), and sulfuric acid tetrahydrate (H2SO4 4H2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4(exp -), and SO4(exp 2-). At high radiation doses, we find that H2SO4 molecules are destroyed completely and that H2SO4 H2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H2SO4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H2SO4 or H2SO4 H2O, the loss of H2SO4 4H2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa s surface, we speculate that the variations in SO2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

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

2011-01-01

284

The Hybrid Sulfur Cycle for Nuclear Hydrogen Production  

Microsoft Academic Search

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

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

2005-01-01

285

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

286

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

287

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

288

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

289

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

290

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?molL-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 sulfurpolysulfide 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 zerovalent 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.

2014-01-01

291

Geochemistry of sulfur in the Florida Everglades; 1994 through 1999  

USGS Publications Warehouse

In this report, we present data on the geochemistry of sulfur in sediments and in surface water, groundwater, and rainwater in the Everglades region in south Florida. The results presented here are part of a larger study intended to determine the roles played by the cycling of carbon, nitrogen, phosphorus, and sulfur in the ecology of the south Florida wetlands. The geochemistry of sulfur in the region is particularly important because of its link to the production of toxic methylmercury through processes mediated by sulfate reducing bacteria. Sediment cores were collected from the Everglades Agricultural Area (EAA), Water Conservation Areas (WCAs) 1A and 2A, from Lake Okeechobee, and from Taylor Slough in the southern Everglades. Water collection was more widespread and includes surface water from WCAs 1A, 2A, 3A, 2B, the EAA, Taylor Slough, Lake Okeechobee, and the Kissimmee River. Groundwater was collected from The Everglades Nutrient Removal Area (ENR) and from WCA 2A. Rainwater was collected at two month intervals over a period of one year from the ENR and from WCA 2A. Water was analyzed for sulfate concentration and sulfate sulfur stable isotopic ratio (34S/32S). Sediment cores were analyzed for total sulfur concentration and/or for concentrations of sulfur species (sulfate, organic sulfur, disulfides, and acid volatile sulfides (AVS)) and for their stable sulfur isotopic ratio. Results show a decrease in total sulfur content (1.57 to 0.61 percent dry weight) with depth in two sediment cores collected in WCA 2A, indicating that there has been an increase in total sulfur content in recent times. A sediment core from the center of Lake Okeechobee shows a decrease in total sulfur content with depth (0.28 to 0.08 percent dry weight). A core from the periphery of the lake (South Bay) likewise shows a decrease in total sulfur content with depth (1.00 to 0.69 percent dry weight), however, the overall sulfur content is greater than that near the center at all depths. This suggests input of sulfur in recent times, especially near the lake margins. Sediments show a general decrease in sulfur concentration with depth, probably because of increases in sulfur input to the marshes in recent times. Regional differences in the concentrations and stable isotopic ratios of sulfate sulfur in surface water show that sulfur contamination to the northern Everglades likely originates from canals draining the EAA.

Bates, Anne L.; Orem, W. H.; Harvey, J. W.; Spiker, E. C.

2000-01-01

292

Biological and Abiological Sulfur Reduction at High Temperatures  

PubMed Central

Reduction of elemental sulfur was studied in the presence and absenc of thermophilic sulfur-reducing bacteria, at temperatures ranging from 65 to 110C, in anoxic artificial seawater media. Above 80C, significant amounts of sulfide were produced abiologically at linear rates, presumably by the disproportionation of sulfur. These rates increased with increasing temperature and pH and were enhanced by yeast extract. In the same medium, the sulfur respiration of two recent thermophilic isolates, a eubacterium and an archaebacterium, resulted in sulfide production at exponential rates. Although not essential for growth, sulfur increased the cell yield in both strains up to fourfold. It is suggested that sulfur respiration is favored at high temperatures and that this process is not limited to archaebacteria, but is shared by other extreme thermophiles.

Belkin, Shimshon; Wirsen, Carl O.; Jannasch, Holger W.

1985-01-01

293

Biological and abiological sulfur reduction at high temperatures  

SciTech Connect

Reduction of elemental sulfur was studied in the presence and absence of thermophilic sulfur-reducing bacteria, at temperatures ranging from 65 to 110/sup 0/C, in anoxic artificial seawater media. Above 80/sup 0/C, significant amounts of sulfide were produced abiologically at linear rates, presumably by the disproportionation of sulfur. These rates increased with increasing temperature and pH and were enhanced by yeast extract. In the same medium, the sulfur respiration of two recent thermophilic isolates, a eubacterium and an archaebacterium, resulted in sulfide production at exponential rates. Although not essential for growth, sulfur increased the cell yield in both strains up to fourfold. It is suggested that sulfur respiration is favored at high temperatures and that this process is not limited to archaebacteria, but is shared by others extreme thermophiles.

Belkin, S.; Wirsen, C.O.; Jannasch, H.W.

1985-05-01

294

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

295

Microbial stabilization of sulfur-landen sorbents; Technical report, September 1--November 30, 1993  

SciTech Connect

Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spent sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species requires additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide, sulfite, or various polythionate species serve as growth substrates for sulfur-oxidizing bacteria, which have the potential to convert all sulfur to sulfate. This quarter, efforts focused on determining the combined effects of dibasic acids (DBA) and Ca{sup +2} concentration on several strains of neutrophilic thiobacilli, including Thiobacillus neapolitanus ATCC 23639 and ATCC 23641, and an isolate, TQ1, which was obtained from a commercial sulfur dioxide scrubber that utilizes DBA.

Miller, K.W. [Illinois State Univ., Normal, IL (United States)

1993-12-31

296

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.

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

1982-01-01

297

Electron Collision Data: Sulfur Hexafluorine  

NSDL National Science Digital Library

Tables of electron interaction cross sections, electron transport parameters, and information about references, uncertainties, and data needs regarding sulfur hexafluorine (SF-6) are provided here by the Electronics and Electronic Engineering Laboratory (EEEL) of the National Institute of Standards and Technology (NIST). These data come out of NIST's mission to provide a complete set of reliable electron collision data for gases used in the plasma processing of semiconductor devices. Along with the tables are color graphs of electron energy vs. cross section and electron transport coefficients for SF-6.

298

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

299

Determination of Sulfur Trioxide in Oleum/Nitric Acid Mixtures.  

National Technical Information Service (NTIS)

A method of analysis is described for determination of the sulfur trioxide content of oleum/nitric acid mixtures found in the low temperature continuous TNT process. This method consists of the indirect determination of sulfur trioxide, via the water cons...

R. Manno C. Ribaudo

1974-01-01

300

Method for removal of sulfur compounds from a gas stream  

SciTech Connect

This invention relates to a process for the removal of sulfur compounds from a gas stream. More specifically, this invention relates to an improvement in the iron oxide method of sulfur removal from a gas stream through the use of hydrogen peroxide.

Frech, K.J.; Tazuma, J.J.

1982-01-19

301

Method for removal of sulfur compounds from a gas stream  

Microsoft Academic Search

This invention relates to a process for the removal of sulfur compounds from a gas stream. More specifically, this invention relates to an improvement in the iron oxide method of sulfur removal from a gas stream through the use of hydrogen peroxide.

K. J. Frech; J. J. Tazuma

1982-01-01

302

Removal of sulfur compounds in fluidized bed carbonaceous solids gasification  

Microsoft Academic Search

This patent describes a process for gasifying sulfur containing carbonaceous feed solids in a single bed maintained fluidized by fluidizing gas introduced through a perforated sloping bed support grid within a single gasification reactor having a density\\/size selective solids withdrawal conduit at a base portion of the bed with upflowing withdrawal gas. It comprises: introducing sulfur containing carbonaceous feed solids

1989-01-01

303

40 CFR 60.104 - Standards for sulfur oxides.  

Code of Federal Regulations, 2013 CFR

...a flare of process upset gases or fuel gas that is released to the...cause the discharge of any gases into the atmosphere from any Claus sulfur recovery plant containing...volume of reduced sulfur compounds and 10 ppm by volume...

2013-07-01

304

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

SciTech Connect

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

Attar, A.

1983-05-01

305

Sodium-sulfur thermal battery  

SciTech Connect

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 sulfur and fluid sodium polysulfides therethrough during operation of the thermal battery to form a mixed polysulfides electrolyte gradient within the separator.

Ludwig, F.A.

1990-12-11

306

Effect of different types of elemental sulfur on bioleaching of heavy metals from contaminated sediments.  

PubMed

The application of two different types of elemental sulfur (S0) was studied to evaluate the efficiency on bioleaching of heavy metals from contaminated sediments. Bioleaching tests were performed in suspension and in the solid-bed with a heavy metal contaminated sediment using commercial sulfur powder (technical sulfur) or a microbially produced sulfur waste (biological sulfur) as substrate for the indigenous sulfur-oxidizing bacteria and thus as acid source. Generally, using biological sulfur during suspension leaching yielded in considerably better results than technical sulfur. The equilibrium in acidification, sulfur oxidation and metal solubilization was reached already after 10-14 d of leaching depending upon the amount of sulfur added. The metal removal after 28 d of leaching was higher when biological sulfur was used. The biological sulfur added was oxidized with high rate, and no residual S0 was detectable in the sediment samples after leaching. The observed effects are attributable to the hydrophilic properties of the biologically produced sulfur particles resulting in an increased bioavailability for the Acidithiobacilli. In column experiments only poor effects on the kinetics of the leaching parameters were observed replacing technical sulfur by biological sulfur, and the overall metal removal was almost the same for both types of S0. Therefore, under the conditions of solid-bed leaching the rate of sulfur oxidation and metal solubilization is more strongly affected by transport phenomena than by microbial conversion processes attributed to different physicochemical properties of the sulfur sources. The results indicate that the application of biological sulfur provides a suitable means for improving the efficiency of suspension leaching treatments by shortening the leaching time. Solid-bed leaching treatments may benefit from the reuse of biological sulfur by reducing the costs for material and operating. PMID:16054192

Seidel, Heinz; Wennrich, Rainer; Hoffmann, Petra; Lser, Christian

2006-03-01

307

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

NASA Technical Reports Server (NTRS)

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

Moses, Julianne I.; Nash, Douglas B.

1991-01-01

308

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

NASA Astrophysics Data System (ADS)

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

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

1991-02-01

309

Development of industrial methods of analysis of sulfur compounds in coal process streams. Tenth quarterly technical progress report, January-March 1980  

SciTech Connect

The concept of molar distribution coefficients (MDC) has been adapted to computerized estimation of aqueous sulfur moiety concentrations in complex mixtures, as a function of pH, redox potential and temperature. The electrooxidation of tetrathionate was ascertained to proceed with 100% current efficiency at a rotated glassy carbon disk anode. The reaction of hydroxymercury benzoate (HMB) with polysulfides was investigated by thermometric enthalpy titrations. Differential pulse voltammetry at a rotated glassy carbon disk anode has been successfully applied to selectively identify and accurately quantitate dibenzothiophene (DBT) in a DOE-NSF surrogate analysis sample, consisting of SRC II products blended to simulate No. 2 fuel oil. The relevant DBT content was 0.14%.

Jordan, J.

1980-04-01

310

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

311

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.-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.

Jin, Yun (Peking, CN); Yu, Qiquan (Peking, CN); Chang, Shih-Ger (El Cerrito, CA)

1996-01-01

312

Sulfur in achondritic meteorites  

NASA Astrophysics Data System (ADS)

The sulfur abundances of samples of nearly 50 achondrites were examined to enlarge the database on the sulfur contents of various categories of achondrites. The study covered eucrites, howardites, diogenites, shergottites, chassignites, nakhilites, aubrites and three unique specimens. The study was spurred by the possibility that the S abundances could help identify the meteorites as originating on Mars or Venus. The S abundances and distributions varied widely, but confirmed that the data were valid indicators of the brecciation and thermal metamorphic history of each meteorite.

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

1985-09-01

313

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

314

Sulfur Concrete for Polar Construction.  

National Technical Information Service (NTIS)

Experimental studies on sulfur concrete in the laboratory and at McMurdo Station, Antarctica are described. Sulfur concrete mixtures showed high tensile, flexural, and compressive strengths as well as high Young's Modulus in the laboratory.

J. R. Keeton

1972-01-01

315

Microbial stabilization of sulfur-laden sorbents. Final technical report, September 1, 1992--August 31, 1993  

SciTech Connect

Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spent sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species requires additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide or sulfite can serve as growth substrates for sulfur-oxidizing bacteria, which convert all sulfur to sulfate. The goals of this project are the following: (1) to optimize conditions for sulfate generation from sulfide, thiosulfate, and sulfite; (2) to test and optimize the effectiveness of microbial processing on spent sorbents from flue gas desulfurization, coal gasification, and fluidized bed combustion; (3) to search for hyperalkalinophilic thiobacilli, which would be effective up to pH 11.

Miller, K.W. [Illinois State Univ., Normal, IL (United States); Hillyer, D.

1993-12-31

316

Reduction of sulfur in Indiana coal by washability techniques. Environmental study II  

Microsoft Academic Search

Fifteen 1-ton bulk samples of Indiana coal were studied in detail by the Indiana Geological Survey in an attempt to reduce the sulfur content. Laboratory techniques of crushing, screening, and making separations based on specific gravity simulated the cleaning processes used in modern industry-operated coal preparation plants. Sulfide, sulfate, organic sulfur, and total sulfur were determined for each fractional sample

C. E. Wier; H. C. Hutchison

1977-01-01

317

The preferential growth of pyrite films prepared by thermal sulfuration of Fe 2O 3 films  

Microsoft Academic Search

Pyrite thin films were prepared by the solgel dip coating process and sulfuration treatment. The evolution of crystal orientation for the pyrite films was investigated as a function of sulfuration temperature. And the effect of crystal orientation on the electrical and optical properties was studied. It was found that films show (111) preferred orientation after sulfurized at low temperature. However,

Z. J. Luan; L. Y. Huang; F. Wang; L. Meng

318

Sulfuric acid in the Venus clouds.  

NASA Technical Reports Server (NTRS)

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

Sill, G. T.

1972-01-01

319

Development of the Hybrid Sulfur Thermochemical Cycle.  

National Technical Information Service (NTIS)

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 baselin...

W. A. Summers J. L. Steimke

2005-01-01

320

Study of Sulfur Recovery from Coal Refuse.  

National Technical Information Service (NTIS)

During coal preparation, a coal refuse of no commercial value is produced and discarded in piles. As rainfall percolates through the piles, acid waters are formed. A feasibility study has been performed on a process producing sulfur from such coal refuse....

P. J. LaRosa H. J. Michaels

1971-01-01

321

Hot-Gas Desulfurization with Sulfur Recovery  

SciTech Connect

The objective of this study is to develop a second generation HGD process that regenerates the sulfided sorbent directly to elemental sulfur using SO{sub 2}, with minimal consumption of coal gas. The goal is to have better overall economics than DSRP when integrated with the overall IGCC system.

Portzer, Jeffrey W.; Damle, Ashok S.; Gangwal, Santosh K.

1997-07-01

322

Atmospheric Sulfur and Fossil Fuel Combustion  

Microsoft Academic Search

Sulfate-chloride ratios in ice samples from the Greenland ice sheet indicate that the combustion of fossil fuels is now introducing slightly more sulfur into the atmosphere than such natural processes as volcanism and the oxidation of hydrogen sulfide derived from organic matter. The amount of sulfate co-varies with the amount of lead in the recent glacial strata, which fact suggests

Minoru Koide; Edward D. Goldberg

1971-01-01

323

Formation of insoluble, nonhydrolyzable, sulfur-rich macromolecules via incorporation of inorganic sulfur species into algal carbohydrates  

NASA Astrophysics Data System (ADS)

The process of sulfur incorporation into organic matter was simulated in the laboratory by sulfurization of cell material of the prymnesiophyte alga Phaeocystis in sea water with inorganic polysulfides at 50C. Flash pyrolysis of the residue, obtained after extraction and several hydrolysis steps, yielded mainly C 1-C 4 alkylbenzenes and C 1-C 4 alkylphenols and, in contrast to control and blank experiments, relatively high amounts of C 0-C 4 alkylthiophenes. The distribution of the thiophenes is very similar to that in pyrolysates of type II-S kerogens. The formation of high-molecular-weight sulfur-rich macromolecules co-occurs with a marked drop in the content of hydrolyzable carbohydrates. This indicates that sulfurization results in the preservation of algal carbohydrate carbon in a macromolecular structure composed of (poly)sulfidic cross-linked carbohydrate skeletons, which upon pyrolysis yields alkylthiophenes. Sulfurization of glucose under similar conditions resulted in the formation of a nonhydrolyzable, solid material, which yielded high amounts of organic sulfur compounds upon pyrolysis, mainly short-chain alkylthiophenes, although with a different distribution than that in the pyrolysate of the sulfurized algal material. The carbon numbers of these organic sulfur compounds extend beyond six, indicating that the length of the carbon skeleton of the pyrolysis products is not limited by the length of the carbon skeleton of the substrate. These results suggest that the sulfurization of carbohydrates may be an important pathway in the preservation of organic matter in euxinic depositional environments.

Kok, Marika D.; Schouten, Stefan; Sinninghe Damst, Jaap S.

2000-08-01

324

Adventures in Organic Sulfur Chemistry  

Microsoft Academic Search

On several occasions, SULFUR REPORTS has invited persons who have done outstanding work in sulfur chemistry to summarize highlights of their research career in a semiautobiographical review. The present account is from a distinguished chemist who has contributed importantly for nearly 50 years to medicinal and organic aspects of sulfur chemistry. Ernest E. Campaigne (who prefers simply E. Campaigne) was

E. Campaigne

1990-01-01

325

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

326

Sulfur Dioxide Detector.  

National Technical Information Service (NTIS)

A composition is provided for detecting the presence of sulfur dioxide by changing color. One type of composition is prepared by mixing a small amount of finely ground potassium permanganate with finely powdered activated silica gel to produce a lilac col...

J. A. Amy H. C. Huber

1980-01-01

327

CONTROLLING SULFUR OXIDES  

EPA Science Inventory

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

328

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...

329

Thermophilic Carbon-Sulfur-Bond-Targeted Biodesulfurization  

PubMed Central

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

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

1997-01-01

330

Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Technical report, December 1, 1991--February 29, 1992  

SciTech Connect

A pre-combustion coal desulfurization process at 120{degree}C using perchloroethylene (PCE) to remove up to 70% of the organic sulfur has been developed by the Midwest Ore Processing Co. (MWOPC). However, this process has not yet proven to be as successful with Illinois coals as it has for Ohio and Indiana coals. In addition, the high levels of organic sulfur removals observed by the MWOPC may be due to certain errors involved in the ASTM data interpretation; this needs verification. For example, elemental sulfur extracted by the PCE may be derived from pyrite oxidation during coal preoxidation, but it may be interpreted as organic sulfur removed by the PCE using ASTM analysis. The purposes of this research are to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization process reported by the MWOPC and to verify the forms-of-sulfur determination using the ASTM method for the PCE process evaluation.

Chou, M.I.M; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Frost, J.K. [Illinois State Geological Survey, Champaign, IL (United States); Buchanan, D.H. [Eastern Illinois Univ., Charleston, IL (United States); Stucki, J.W. [Illinois Univ., Urbana, IL (United States); Huffman, G.; Huggins, F.E. [Kentucky Univ., Lexington, KY (United States)

1992-09-01

331

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

2013-06-01

332

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

2013-06-01

333

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

334

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, October-December 1981. [P-hydroxymercuribenzoate  

SciTech Connect

The reaction between thiosulfate and p-hydroxymercuribenzoate (HMB) was investigated because it can interfere with the determination of HS/sup -/ and the polysulfides by thermometric titration. The following approximate assignments were obtained: ..delta..H/sup 0/' = -13.7 kJ/mole and ..delta..G/sup 0/' = -10.1 kJ/mole at 25/sup 0/C. The literature on the chemistry of the moieties S/sub 2/O/sub 4//sup 2 -/, S/sub 2/O/sub 6//sup 2 -/, S/sub 3/O/sub 6//sup 2 -/, S/sub 4/O/sub 6//sup 2 -/, S/sub 5/O/sub 6//sup 2 -/, S/sub 6/O/sub 6//sup 2 -/ is reviewed critically as the basis for new analytical methods development. The various moieties exhibit salient differences in behavior related to sulfur chain length. Properties affected include precipitation, cleavage, and electron transfer reactivities, which may have analytical significance.

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

1982-01-01

335

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--March 31, 1996  

SciTech Connect

During the tenth quarter of the project, bench scale experiments were performed to investigate the adsorption ability of different kinds of materials within sulfur vapor environment. Four kinds of adsorbents have been tested. The experimental results indicated that activated carbon was the best of four adsorbents tested. In addition to the baseline tests, several designs of activated carbon feed system have been tested. Under an inert environment, bench scale experiments were performed to investigate the characteristics and efficiency of activated carbon passing through the Co-Mo-Alumina catalyst bed. The results showed that activated carbon powder could easily be transported through the catalytic bed. The adsorption process may be applicable to promote conversion of H{sub 2}S in the H{sub 2}S and CO{sub 2} reaction system.

Gong, S.Y.; Jiang, X.; Khang, S.J.; Keener, T.C.

1996-12-31

336

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

SciTech Connect

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

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

1983-07-01

337

ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY.  

National Technical Information Service (NTIS)

This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In th...

A. L. Ortiz D. P. Harrison F. R. Groves J. D. White S. Zhang

1998-01-01

338

Method for removal of sulfur compounds from a gas  

SciTech Connect

This invention relates to a process for the removal of sulfur compounds from a gas stream which consists of contacting said gas stream with alkali metal salts of sulfonamides or resins containing sulfonamide functionalities.

Frech, K.J.; Tazuma, J.J.

1981-08-11

339

Method for removal of sulfur compounds from a gas  

Microsoft Academic Search

This invention relates to a process for the removal of sulfur compounds from a gas stream which consists of contacting said gas stream with alkali metal salts of sulfonamides or resins containing sulfonamide functionalities.

K. J. Frech; J. J. Tazuma

1981-01-01

340

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

NASA Astrophysics Data System (ADS)

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: 4H 2O + 4S 0 ? 3H 2S + SO 42- + 2H +In the present study, stable oxygen isotope fractionation during formation of sulfate via this reaction was experimentally investigated for a pure culture (Desulfocapsa thiozymogenes) and an enrichment culture ("Kuhgraben") at 28C. Synthetic FeCO 3 and FeOOH were used as scavengers for hydrogen sulfide to keep the disproportionation reaction exergonic and to suppress polysulfide formation and isotope exchange between elemental sulfur and hydrogen sulfide. Compared to water, dissolved sulfate was enriched in 18O by +17.4 0.1 ( Desulfocapsa thiozymogenes) and +16.6 0.5 (Kuhgraben) at cell specific sulfur disproportionation rates of 10 -15.4 0.4 mol S cell -1 h -1 and 10 -14.4 0.9 mol S cell -1 h -1, respectively. Oxygen isotope fractionation was not influenced by the type of iron-bearing scavenger used, corroborating earlier findings that H 2S oxidation by FeOOH yields elemental sulfur as the dominant oxidation product. Sulfite is suggested to be formed as a metabolic intermediate to facilitate isotope exchange with water. Due to bacterial disproportionation, dissolved sulfate was also enriched in 34S compared to elemental sulfur by +11.0 to +18.4 ( D. thiozymogenes) and +12.7 to +17.9 (Kuhgraben). FeS was depleted in 32S compared to elemental sulfur by -3.7 to -5.3 ( D. thiozymogenes).

Bttcher, M. E.; Thamdrup, B.; Vennemann, T. W.

2001-05-01

341

Human impact on the atmospheric sulfur balance  

NASA Astrophysics Data System (ADS)

The paper reviews the development in our understanding of the atmospheric part of the global sulfur cycle, including the role played by C.-G. Rossby and his colleagues in the 1950s, and presents a brief assessment of the current knowledge. Measurements of the concentrations of sulfur compounds in air, precipitation, ice cores and sea water during the past 25years, together with recent development in three-dimensional tracer transport modeling, have resulted in a reasonably consistent picture of the burdens and fluxes of the main sulfur compounds in the atmosphere. It is clear that man's activities, in particular the burning of fossil fuels, are having a large impact on the atmospheric sulfur balance. Even on a global scale, the man-made emissions of gaseous sulfur compounds are likely to be two to three times as large as the natural sources. In and around the most heavily industrialized regions this ratio exceeds ten over extended areas. Nevertheless, there are several important issues that need to be resolved. Some of these are directly linked to the urgent problem of reducing the uncertainty in the estimate of direct and, in particular, indirect climate forcing due to man-made sulfate aerosols. One such issue is the magnitude of the wet scavenging of SO2 and aerosol sulfate during upward transport into and within the free troposphere in connection with convective and frontal cloud systems which has a decisive influence on the sulfate concentrations in the upper troposphere. Another uncertain process is the rate of oxidation of SO2 in cloud droplets and on aerosol particles. A fundamental question that remains to be answered is to what degree man-made sulfur emissions have increased the number of aerosol particles that can act as cloud condensation nuclei.

Rodhe, Henning

1999-02-01

342

Human impact on the atmospheric sulfur balance  

NASA Astrophysics Data System (ADS)

The paper reviews the development in our understanding of the atmospheric part of the global sulfur cycle, including the role played by C.-G. Rossby and his colleagues in the 1950s, and presents a brief assessment of the current knowledge. Measurements of the concentrations of sulfur compounds in air, precipitation, ice cores and sea water during the past 25years, together with recent development in three-dimensional tracer transport modeling, have resulted in a reasonably consistent picture of the burdens and fluxes of the main sulfur compounds in the atmosphere. It is clear that man's activities, in particular the burning of fossil fuels, are having a large impact on the atmospheric sulfur balance. Even on a global scale, the man-made emissions of gaseous sulfur compounds are likely to be two to three times as large as the natural sources. In and around the most heavily industrialized regions this ratio exceeds ten over extended areas. Nevertheless, there are several important issues that need to be resolved. Some of these are directly linked to the urgent problem of reducing the uncertainty in the estimate of direct and, in particular, indirect climate forcing due to man-made sulfate aerosols. One such issue is the magnitude of the wet scavenging of SO2 and aerosol sulfate during upward transport into and within the free troposphere in connection with convective and frontal cloud systems which has a decisive influence on the sulfate concentrations in the upper troposphere. Another uncertain process is the rate of oxidation of SO2 in cloud droplets and on aerosol particles. A fundamental question that remains to be answered is to what degree man-made sulfur emissions have increased the number of aerosol particles that can act as cloud condensation nuclei.

Rodhe, Henning

1999-01-01

343

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

344

Sulfur in the atmosphere  

Microsoft Academic Search

In unpolluted areas sulfur occurs primarily in three compounds, SO\\/sup 2 -\\/ in aerosols and SO and HS in gas. Sources of SO\\/sup 2 -\\/ are the ocean, the soil, and the oxidation of the gaseous compounds. A considerable fraction of the SO is of anthropogenic origin. As measurements in polluted and unpolluted areas indicate, most of the HS seems

C. E. Junge

1960-01-01

345

Sulfur and primary production in aquatic environments: an ecological perspective.  

PubMed

Sulfur is one of the critical elements in living matter, as it participates in several structural, metabolic and catalytic activities. Photosynthesis is an important process that entails the use of sulfur during both the light and carbon reactions. Nearly half of global photosynthetic carbon fixation is carried out by phytoplankton in the aquatic environment. Aquatic environments are very different from one another with respect to sulfur content: while in the oceans sulfate concentration is constantly high, freshwaters are characterized by daily and seasonal variations and by a wide range of sulfur concentration. The strategies that algal cells adopt for energy and resource allocation often reflect these differences. In the oceans, the amount and chemical form of sulfur has changed substantially during the course of the Earth's history; it is possible that sulfur availability played a role in the evolution of marine phytoplankton communities and it may continue to have appreciable effects on global biogeochemistry and ecology. Phytoplankton is also the main biogenic source of sulfur; sulfur can be released into the atmosphere by algal cells as dimethylsulfide, with possibly important repercussions on global climate. These and related matters are discussed in this review. PMID:16307310

Norici, Alessandra; Hell, Ruediger; Giordano, Mario

2005-12-01

346

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

347

Development of the Hybrid Sulfur Thermochemical Cycle  

Microsoft Academic Search

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

William A. Summers; John L. Steimke

2005-01-01

348

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

349

Elemental sulfur analysis  

NASA Astrophysics Data System (ADS)

Elemental sulfur as total zerovalent sulfur, S(0), is frequently measured in anoxic and/or sulfidic waters, and at the interface of oxic and anoxic waters. Examples of bodies of water with oxic-anoxic interfaces are the Black Sea, Kau Bay, the Cariaco Trench, the northern Chesapeake Bay, Saanich inlet, Framvaren fjord and the brines at the bottom of the Mediterranean Sea. The sampling and analytical procedures commonly used are given below. Samples are obtained from Go-Flo bottles off the CTD rosette system. The Go-Flo bottles are attached to a N2 cylinder to maintain N2 over the water during collection. A positive pressure is maintained so that water from the bottles would be able to be filtered hermetically through 0.2 ?m Nuclepore filters directly into polypropylene or glass syringes. The syringes are equipped with three way stopcocks so that the lines from the Go-Flo bottles can be purged of air during sampling. This insures that no O2 can enter the syringe or the filter device and cause sulfide oxidation resulting in elemental sulfur formation. The syringes are stored in N2 filled glove bags or ziploc bags for subsequent analysis.

Luther, George W., III

350

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

351

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

352

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

353

The fate of sulfur in mild gasification liquids  

SciTech Connect

This investigation addresses the determination of sulfur distribution in mild gasification liquids produced from untreated coal and from modified in two ways to reduce sulfur in the products: (a) physical mixing with a sulfur scavenger (CaO), and (b) pretreatment with aqueous alkali followed by mixing with CaO. Coal pyrolysis in the presence of CaO has previously been investigated, (3,5) showing that CaO can be effective in reducing the sulfur content of the fuel gas, and possibly that of the product liquids. Pretreatment of coals with alkaline chemicals has also been studied,(6,7) showing reduced sulfur and other changes in the liquid products.(8) Data on sulfur distribution in the liquid products could be useful for understanding the chemistry of alkali pretreatment and CaO interaction with coal sulfur during pyrolysis. In this work, a pyrolysis-gas chromatography (Py-GC) technique that simulates mild gasification on a milligram scale was used in conjunction with a carbon-specific flame ionization detector (FID) and a sulfur-specific flame photometric detector (FPD) to determine the sulfur distribution in oils/tars from Illinois No. 6 coal. A low-resolution packed GC column was employed to resolve oils/tars by carbon number, with ranges selected to approximate distillation fractions which might be recovered from a commercial mild gasification process. Oils/tars up to C{sub 18} were also collected from the pyro-probe effluent into dichloromethane for off-line study using a high-resolution GC with atomic emission detector (GC/AED) and with GC-mass spectrometry (GC/MS) to measure specific sulfur compounds. 9 refs., 1 tab.

Knight, R.A.; Koncar, G.J.; Babu, S.P.

1991-01-01

354

Identification of sulfur fumed Pinelliae Rhizoma using an electronic nose  

PubMed Central

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

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

2014-01-01

355

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

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

2014-01-01

356

Recovery of Zinc and Sulfur from Sphalerite Concentrates by Reaction with Sulfuric Acid.  

National Technical Information Service (NTIS)

The Bureau of Mines constructed a process research unit (PRU) to demonstrate new technology for extracting zinc from sphalerite concentrates. Up to 9 kg/hr of sphalerite (ZnS) concentrate was reacted at ambient pressure in the PRU with 80 pct sulfuric aci...

A. A. Cochran H. H. Dewing S. E. Lay

1982-01-01

357

Quadruple sulfur isotope constraints on the origin and cycling of volatile organic sulfur compounds in a stratified sulfidic lake  

NASA Astrophysics Data System (ADS)

We have quantified the major forms of volatile organic sulfur compounds (VOSCs) distributed in the water column of stratified freshwater Fayetteville Green Lake (FGL), to evaluate the biogeochemical pathways involved in their production. The lake's anoxic deep waters contain high concentrations of sulfate (1216 mmol L?1) and sulfide (0.12 ?mol L?1 to 1.5 mmol L?1) with relatively low VOSC concentrations, ranging from 0.1 nmol L?1 to 2.8 ?mol L?1. Sulfur isotope measurements of combined volatile organic sulfur compounds demonstrate that VOSC species are formed primarily from reduced sulfur (H2S/HS?) and zero-valent sulfur (ZVS), with little input from sulfate. Thedata support a role of a combination of biological and abiotic processes in formation of carbonsulfur bonds between reactive sulfur species and methyl groups of lignin components. These processes are responsible for very fast turnover of VOSC species, maintaining their low levels in FGL. No dimethylsulfoniopropionate (DMSP) was detected by Electrospray Ionization Mass Spectrometry (ESI-MS) in the lake water column or in planktonic extracts. These observations indicate a pathway distinct from oceanic and coastal marine environments, where dimethylsulfide (DMS) and other VOSC species are principally produced via the breakdown of DMSP by plankton species.

Oduro, Harry; Kamyshny, Alexey; Zerkle, Aubrey L.; Li, Yue; Farquhar, James

2013-11-01

358

Sulfuric acid as autocatalyst in the formation of sulfuric acid.  

PubMed

Sulfuric acid can act as a catalyst of its own formation. We have carried out a computational investigation on the gas-phase formation of H(2)SO(4) by hydrolysis of SO(3) involving one and two water molecules, and also in the presence of sulfuric acid and its complexes with one and two water molecules. The hydrolysis of SO(3) requires the concurrence of two water molecules, one of them acting as a catalyzer, and our results predict an important catalytic effect, ranging between 3 and 11 kcalmol(-1) when the catalytic water molecule is substituted by a sulfuric acid molecule or one of its hydrates. In these cases, the reaction products are either bare sulfuric acid dimer or sulfuric acid dimer complexed with a water molecule. There are broad implications from these new findings. The results of the present investigation show that the catalytic effect of sulfuric acid in the SO(3) hydrolysis can be important in the Earth's stratosphere, in the heterogeneous formation of sulfuric acid and in the formation of aerosols, in H(2)SO(4) formation by aircraft engines, and also in understanding the formation of sulfuric acid in the atmosphere of Venus. PMID:23198746

Torrent-Sucarrat, Miquel; Francisco, Joseph S; Anglada, Josep M

2012-12-26

359

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

360

The Use of Nahcolite Ore and Bag Filters For Sulfur Dioxide Emission Control  

Microsoft Academic Search

This paper describes some technical and economic aspects of the nahcolite ore injection process for the simultaneous removal of fly ash and sulfur oxides from stack gases. The process is capable of removing greater than 99% of the particulate matter and greater than 70% of the sulfur oxides present in such gases. In the process, nahcolite ore, a naturally occurring

J. M. Genco; H. S. Rosenberg; M. Y. Anastas; E. C. Rosar; J. M. Dulin

1975-01-01

361

Sulfur Compounds in Comets. (Abstract Only)  

National Technical Information Service (NTIS)

Cometary atmospheres exhibit abundant sulfur and sulfur compounds, which are absent in planetary atmospheres. Sulfur compounds were also detected in interstellar media, including SO, SO2, CS, etc., but excluding S2 which was identified only in IRAS-Araki-...

S. Kim M. Ahearn

1989-01-01

362

21 CFR 184.1095 - Sulfuric acid.  

Code of Federal Regulations, 2013 CFR

...sulfur dioxide (SO2 ) with oxygen and mixing the resultant sulfur trioxide (SO3 ) with water, or by reacting nitric oxide (NO) with sulfur dioxide and water. (b) The ingredient meets the specifications of the Food...

2013-04-01

363

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

SciTech Connect

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

Robert C. Brown; Maohong Fan

2001-12-01

364

Partial oxidation of sulfur-containing solid carbonaceous fuel  

Microsoft Academic Search

This patent describes a process for the simultaneous partial oxidation and desulfurization of a sulfur and silicate-containing comminuted solid carbonaceous fuel comprising, basis solid fuel, 0.2 to 6.0 wt. % sulfur and 0.1 to 30 wt. % of silicate compounds including iron silicate. The improvements consist of (1) reacting in the free-flow unobstructed down-flowing vertical refractory lined reaction zone of

M. S. Najjar; R. J. Corbeels

1989-01-01

365

Threshold dependence in the electronic sputtering of condensed sulfur  

SciTech Connect

An apparent threshold is found for ejection of neutral sulfur from condensed sulfur due to electronic energy deposited by fast, light ions. This effect is important for understanding experiments on electronically stimulated sputtering (desorption) of large molecules. The threshold is determined by the density of ''ionization'' events deposited in the solid, and the nature of the threshold measured is affected by a material alteration process.

Torrisi, L.; Coffa, S.; Foti, G.; Johnson, R.E.; Chrisey, D.B.; Boring, J.W.

1988-07-15

366

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

367

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

368

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

369

Sulfur specific chromatography using hydrogenalysis  

SciTech Connect

A totally sulfur specific chromatographic detector is described based on the differential colorimetry of lead acetate tape. Its output is linear with concentration, and has no response to compounds other than sulfur compounds. These characteristics are particularly advantageous when analyzing hydrocarbon gases and light hydrocarbon liquids for low part per million and part per billion concentrations of sulfur compounds. As each particular sulfur species is eluted from a chromatograph column it is mixed with hydrogen and swept into a tube furnace. In the furnace, this sulfur peak is changed into a corresponding hydrogen sulfide peak. The corresponding hydrogen sulfide peak is detected by a lead acetate tape based hydrogen sulfide analyzer. Theory of operation, performance characteristics, and applicability of this type of detector are discussed.

Szinyei, W.J. (Tracor Atlas, Inc., 9441 Baythorne Dr., Houston, TX (US))

1988-01-01

370

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

371

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, III, W. C.; Jackson, M. C.

1993-01-01

372

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

Various arylsulfur pentafluorides, ArSF(5), have long been desired in both academic and industrial areas, and ArSF(5) compounds have attracted considerable interest in many areas such as medicines, agrochemicals, and other new materials, since the highly stable SF(5) 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 ZnF(2), 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

Umemoto, Teruo; Garrick, Lloyd M; Saito, Norimichi

2012-01-01

373

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

SciTech Connect

Task 1. Methods development for the speciation of the polysulfides. The chemistry of polysulfides is reviewed in the context of coal-liquefaction condensates. Rearrangements of polysulfides (condensation to longer chain lengths, cleavage and disproportionation) are accounted for by the bifunctional nature of polysulfides as Lewis acids and bases. Classical analytical methods are also reviewed. Task 2. Methods development for the speciation of dithionite and polythionates. A polarographic procedure has been developed for the determination of tetrathionate and pentathionate in the presence of each other. The method is based on measuring diffusion currents (at the dropping mercury electrode) at two discrete potentials. Task 3. Total accounting of the sulfur balance in representative samples of synfuel process streams. Preliminary data are reported on the analysis of two new samples, viz., a gasifier condensate (G-1) and a three year old SRC-II aqueous effluent (L-1). No sulfide or polysulfides were found in either sample. Thiosulfate was detected in L-1. 9 figures, 5 tables.

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

1983-04-01

374

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

375

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

376

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

377

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

378

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...

379

Sulfur developments: low b.t.u. gas for power plants  

Microsoft Academic Search

Direct combustion of high-sulfur coal presents problems. An alternative ; is the production of low Btu gas from coal. Two advantages of this process are: ; that the gas is produced under reducing conditiona, with the result that sulfur ; is converted to HS, which can readily be removed by well-proven absorption ; processes: and aecondly, the gas can be

Conn

1973-01-01

380

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

381

Development of instrumental methods of analysis of sulfur compounds in coal-process streams. Quarterly progress report, July-September 1981. [P-hydroxymercuribenzoate (HMB) titrant  

SciTech Connect

This report covers the eighth 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 as previously reported in DOE/ET/10482--T1 (1981). Task 2: voltammetric methods development. The polarography of mixtures containing HS/sup -1/, S/sub 4//sup -2/ and S/sub 5//sup -2/ was investigated at the dropping mercury electrode in aqueous supporting electrolytes of pH 8.7 and 9.4. Cathodic waves were obtained which exhibited a large polarographic maximum, followed by a well-defined limiting current region. The limiting current was proportional to the sum of (S/sub 4//sup -2/) + (S/sub 5//sup -2/). An anomaly that interfered at pH 12, viz., a dip in the limiting current spanning half a volt, was minimized at pH < 9. Task 3: enthalpimetric methods development. Thermochemical data collection, storage, and analysis have been fully computerized. Thermometric enthalpy titration curves (TET) were computer corrected to yield an enthalpogram in terms of net heats of chemical reactions plotted versus time. The latter represents a measure of volume of titrant added, because the titrant was delivered at constant rate. Non-idealities such as heat capacity changes and extraneous heat losses were automatically compensated. The reagent p-hydroxymercuribenzoate (HMB) used as a titrant yielded thermometric endpoints from which discrete estimates of sulfide and polysulfide content were obtained. Task 4: application and technology transfer to coal conversion plants. A thermochemical method for determining polysulfides, utilizing HMB as a titrant, has been validated in an aqueous coal liquefaction process stream. Polysulfides can be detected in up to a 50-fold excess of HS/sup -/.

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

1981-10-01

382

Novel Sulfur-Tolerant Anodes for Solid Oxide Fuel Cells  

SciTech Connect

One of the unique advantages of SOFCs over other types of fuel cells is the potential for direct utilization of hydrocarbon fuels (it may involve internal reforming). Unfortunately, most hydrocarbon fuels contain sulfur, which would dramatically degrade SOFC performance at parts-per-million (ppm) levels. Low concentration of sulfur (ppm or below) is difficult to remove efficiently and cost-effectively. Therefore, knowing the exact poisoning process for state-of-the-art anode-supported SOFCs with Ni-YSZ cermet anodes, understanding the detailed anode poisoning mechanism, and developing new sulfur-tolerant anodes are essential to the promotion of SOFCs that run on hydrocarbon fuels. The effect of cell operating conditions (including temperature, H{sub 2}S concentration, cell voltage/current density, etc.) on sulfur poisoning and recovery of nickel-based anode in SOFCs was investigated. It was found that sulfur poisoning is more severe at lower temperature, higher H{sub 2}S concentration or lower cell current density (higher cell voltage). In-situ Raman spectroscopy identified the nickel sulfide formation process on the surface of a Ni-YSZ electrode and the corresponding morphology change as the sample was cooled in H{sub 2}S-containing fuel. Quantum chemical calculations predicted a new S-Ni phase diagram with a region of sulfur adsorption on Ni surfaces, corresponding to sulfur poisoning of Ni-YSZ anodes under typical SOFC operating conditions. Further, quantum chemical calculations were used to predict the adsorption energy and bond length for sulfur and hydrogen atoms on various metal surfaces. Surface modification of Ni-YSZ anode by thin Nb{sub 2}O{sub 5} coating was utilized to enhance the sulfur tolerance. A multi-cell testing system was designed and constructed which is capable of simultaneously performing electrochemical tests of 12 button cells in fuels with four different concentrations of H{sub 2}S. Through systematical study of state-of-the-art anode-supported SOFC button cells, it is seen that the long-term sulfur poisoning behavior of those cells indicate that there might be a second-stage slower degradation due to sulfur poisoning, which would last for a thousand hour or even longer. However, when using G-18 sealant from PNNL, the 2nd stage poisoning was effectively prohibited.

Lei Yang; Meilin Liu

2008-12-31

383

Refractory sulfur compounds in gas oils  

Microsoft Academic Search

Five heavy straight run gas oils from different crude oils were analyzed by sulfur and carbon sensitive high resolution capillary gas chromatography. Gas oils also were hydrotreated in a fixed bed gas-phase reactor. Model substances, representing refractory sulfur compounds, were converted in a CSTR slurry reactor. Sulfur concentration profiles of the original oils were calculated and showed the sulfur concentration

H Schulz; W Bhringer; F Ousmanov; P Waller

1999-01-01

384

Chemical desulfurization of petroleum fractions for ultra-low sulfur fuels  

Microsoft Academic Search

An improved desulfurization process for removing sulfur from hydro treated diesel oil based on the oxidation of thiophenic type sulfur-containing compounds with H2O2 and acetic acid (AcOH) using H2SO4 as catalyst has been studied. The experimental results show that the sulfone content in the oxidation product increased rapidly with an increase in acetic acid and sulfuric acid ratios from 1:0

Mohammad Farhat Ali; Abdullah Al-Malki; Shakil Ahmed

2009-01-01

385

Photodissociation Studies of Sulfur Oxides.  

National Technical Information Service (NTIS)

The detailed reaction dynamics of several gas phase polyatomic systems has been established in this research at the Department of Chemistry at the University of Puerto Rico. Real time dynamics of sulfur monoxide photoelimination reactions have been studie...

B. R. Weiner

1996-01-01

386

Sodium Sulfur Technology Program NASTEC.  

National Technical Information Service (NTIS)

The NaSTEC program focuses on developing currently available sodium sulfur cells for use in space applications and investigating the operational parameters of the cells. The specific goals of the program are to determine the operational parameters and ver...

B. Highley W. A. Somerville

1992-01-01

387

Potential Antimalarial Organic Sulfur Compounds.  

National Technical Information Service (NTIS)

In an attempt to develop useful antimalarial medicinal agents, a series of twenty two organic sulfur compounds were synthesized which were analogous in structure to 4,4'-diaminodiphenyl sulfone an effective antimalarial. Fifteen of these compounds were N-...

K. K. Andersen J. Bhattacharyya S. K. Mukhopadhyay

1969-01-01

388

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 (H2SO4H2O), and sulfuric acid tetrahydrate (H2SO44H2O) 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

389

Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report, July-September 1983. [Thermometric enthalpy titration of trisulfide and tetrasulfide with thallous nitrate; coulometry of polythionates  

SciTech Connect

Task 1. Methods development for the speciation of the polysulfides. Thermometric enthalpy titration of a mixture of HS/sup -/, trisulfide and tetrasulfide with thallous nitrate yielded a single endpoint corresponding to the sum (HS/sup -/) + (S/sub 3//sup 2 -/) + (S/sub 4//sup 2 -/). The heat evolved (..delta..H/sub obs/ = -138 kJ/mol of thallium) was the weighted average of the heats of the reactions: 2Tl/sup +/ + HS/sup -/ + OH/sup -/ = Tl/sub 2/S(s) + H/sub 2/O; 2Tl/sup +/ + S/sub 3//sup 2 -/ = Tl/sub 2/S/sub 3/(s); 2Tl/sup +/ + S/sub 4//sup 2 -/ = Tl/sub 2/S/sub 4/(s). Task 2. Methods development for the speciation of dithionite and polythionates. In a solvent consisting of 40% ethanol and 60% water, coulometric current-time integrals substantiated the occurrence of the following electrode reactions: S/sub 3/O/sub 6//sup 2 -/+ 2e = S/sub 2/O/sub 3//sup 2 -/ + SO/sub 3//sup 2 -/; S/sub 4/O/sub 6//sup 2 -/ + 2e = 2S/sub 2/O/sub 3//sup 2 -/; S/sub 5/O/sub 6//sup 2 -/ + 4e + 2H/sub 2/O = 2S/sub 2/O/sub 3//sup 2 -/ + H/sub 2/S + 2OH/sup -/. Corresponding polarographic diffusion currents are amenable to the analysis of mixture of polythionates. Task 3. Total accounting of the sulfur balance in representative samples of synfuel process streams. Analyses of three aqueous liquefaction specimens, a Disposable Catalyst Development (DCD) process effluent from Pittsburgh, PA, and two effluents generated by three separate process units from Wilsonville, AL, were undertaken. The Wilsonville effluents resulted from sampling at different wastewater treatment steps. Thiosulfate and sulfate were observed in the Wilsonville effluents. The DCD process effluent contained only hydrogen sulfide and polysulfides. 8 references, 2 figures, 5 tables.

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

1983-10-01

390

Emission of sulfur from Lake Ontario sediments  

Microsoft Academic Search

Calculations indicate that about 6.0 x 10⁵ kg of sulfur is released annually from Lake Ontario sediments. This constitutes about 1% of the annual sulfur input into the sediments and is insignificant compared to the total sulfur that cycles annually through the lake. The sulfur released from the sediments is enriched in ³²S with the result that the sulfur in

J. O. Nriagu; R. D. Coker

1976-01-01

391

Disproportionation of elemental sulfur by haloalkaliphilic bacteria from soda lakes.  

PubMed

Microbial disproportionation of elemental sulfur to sulfide and sulfate is a poorly characterized part of the anoxic sulfur cycle. So far, only a few bacterial strains have been described that can couple this reaction to cell growth. Continuous removal of the produced sulfide, for instance by oxidation and/or precipitation with metal ions such as iron, is essential to keep the reaction exergonic. Hitherto, the process has exclusively been reported for neutrophilic anaerobic bacteria. Here, we report for the first time disproportionation of elemental sulfur by three pure cultures of haloalkaliphilic bacteria isolated from soda lakes: the Deltaproteobacteria Desulfurivibrio alkaliphilus and Desulfurivibrio sp. AMeS2, and a member of the Clostridia, Dethiobacter alkaliphilus. All cultures grew in saline media at pH 10 by sulfur disproportionation in the absence of metals as sulfide scavengers. Our data indicate that polysulfides are the dominant sulfur species under highly alkaline conditions and that they might be disproportionated. Furthermore, we report the first organism (Dt. alkaliphilus) from the class Clostridia that is able to grow by sulfur disproportionation. PMID:24030483

Poser, Alexander; Lohmayer, Regina; Vogt, Carsten; Knoeller, Kay; Planer-Friedrich, Britta; Sorokin, Dimitry; Richnow, Hans-H; Finster, Kai

2013-11-01

392

Evaluation of sulfur-reducing microorganisms for organic desulfurization  

SciTech Connect

Because a substantial portion of the sulfur in Illinois coal is organically bound sulfur, microbial desulfurization of sulfidic and thiophenic functionalities holds great potential for complementing pyritic sulfur removal. The release of H{sub 2}S from anaerobic systems such as the gut, sewage, and marine and freshmwater sediments, is a common occurrence and the role of microorganisms in this process has long been recognized. The principal goals of our project are: to obtain anaerobic microbial cultures that produce H{sub 2}S from compounds representative of the organosulfur functionalities in coal; to optimize this activity; to evaluate the effectiveness of using these cultures to remove organic sulfur from Illinois coal. Our immediate objectives for this year are the following: to obtain additional cultures from coal mine waste and municipal sewage sludge, two environments previously unexplored by our laboratory; to continue optimizing activity in cultures that desulfurize model compounds, including identification of individual microbial species; to expand coal desulfurization experiments to include additional coals; and, to address the recently discovered problem of sulfide sorbing to coal. This quarter we report on: (1) comparative results from sulfide sorption studies for IBC-101, IBC-108, and a North Dakota lignite; (2) calculation of Gibb's free energies for dissimilatory reduction of selected model compounds; (3) results from experiments in which elemental sulfur was used as a co-reductant to encourage microbial reduction of dibenzothiophene-sulfur to H{sub 2}S. 41 figs., 2 tabs.

Miller, K.W.

1991-01-01

393

Sulfur metabolism in Beggiatoa alba.  

PubMed Central

The metabolism of sulfide, sulfur, and acetate by Beggiatoa alba was investigated under oxic and anoxic conditions. B. alba oxidized acetate to carbon dioxide with the stoichiometric reduction of oxygen to water. In vivo acetate oxidation was suppressed by sulfide and by several classic respiratory inhibitors, including dibromothymoquinone, an inhibitor specific for ubiquinones. B. alba also carried out an oxygen-dependent conversion of sulfide to sulfur, a reaction that was inhibited by several electron transport inhibitors but not by dibromothymoquinone, indicating that the electrons released from sulfide oxidation were shuttled to oxygen without the involvement of ubiquinones. Intracellular sulfur stored by B. alba was not oxidized to sulfate or converted to an external soluble form under aerobic conditions. On the other hand, sulfur stored by filaments of Thiothrix nivea was oxidized to extracellular soluble oxidation products, including sulfate. Sulfur stored by filaments of B. alba, however, was reduced to sulfide under short-term anoxic conditions. This anaerobic reduction of sulfur was linked to the endogenous oxidation of stored carbon and to hydrogen oxidation.

Schmidt, T M; Arieli, B; Cohen, Y; Padan, E; Strohl, W R

1987-01-01

394

METHOD TO PREVENT SULFUR ACCUMULATION INSIDE MEMBRANE ELECTRODE ASSEMBLY  

SciTech Connect

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

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

2009-06-22

395

ENGINEERING EVALUATION OF HOT-GAS DESULFURIZATION WITH SULFUR RECOVERY  

SciTech Connect

Engineering evaluations and economic comparisons of two hot-gas desulfurization (HGD) processes with elemental sulfur recovery, being developed by Research Triangle Institute, are presented. In the first process, known as the Direct Sulfur Recovery Process (DSRP), the SO{sub 2} tail gas from air regeneration of zinc-based HGD sorbent is catalytically reduced to elemental sulfur with high selectivity using a small slipstream of coal gas. DSRP is a highly efficient first-generation process, promising sulfur recoveries as high as 99% in a single reaction stage. In the second process, known as the Advanced Hot Gas Process (AHGP), the zinc-based HGD sorbent is modified with iron so that the iron portion of the sorbent can be regenerated using SO{sub 2} . This is followed by air regeneration to fully regenerate the sorbent and provide the required SO{sub 2} for iron regeneration. This second-generation process uses less coal gas than DSRP. Commercial embodiments of both processes were developed. Process simulations with mass and energy balances were conducted using ASPEN Plus. Results show that AHGP is a more complex process to operate and may require more labor cost than the DSRP. Also capital costs for the AHGP are higher than those for the DSRP. However, annual operating costs for the AHGP appear to be considerably less than those for the DSRP with a potential break-even point between the two processes after just 2 years of operation for an integrated gasification combined cycle (IGCC) power plant using 3 to 5 wt% sulfur coal. Thus, despite its complexity, the potential savings with the AHGP encourage further development and scaleup of this advanced process.

G.W. ROBERTS; J.W. PORTZER; S.C. KOZUP; S.K. GANGWAL

1998-05-31

396

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...

397

Understanding the role of different conductive polymers in improving the nanostructured sulfur cathode performance.  

PubMed

Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies because of their high theoretical specific energy, but their wide-scale implementation has been impeded by a series of challenges, especially the dissolution of intermediate polysulfides species into the electrolyte. Conductive polymers in combination with nanostructured sulfur have attracted great interest as promising matrices for the confinement of lithium polysulfides. However, the roles of different conductive polymers on the electrochemical performances of sulfur electrode remain elusive and poorly understood due to the vastly different structural configurations of conductive polymer-sulfur composites employed in previous studies. In this work, we systematically investigate the influence of different conductive polymers on the sulfur cathode based on conductive polymer-coated hollow sulfur nanospheres with high uniformity. Three of the most well-known conductive polymers, polyaniline (PANI), polypyrrole (PPY), and poly(3,4-ethylenedioxythiophene) (PEDOT), were coated, respectively, onto monodisperse hollow sulfur nanopsheres through a facile, versatile, and scalable polymerization process. The sulfur cathodes made from these well-defined sulfur nanoparticles act as ideal platforms to study and compare how coating thickness, chemical bonding, and the conductivity of the polymers affected the sulfur cathode performances from both experimental observations and theoretical simulations. We found that the capability of these three polymers in improving long-term cycling stability and high-rate performance of the sulfur cathode decreased in the order of PEDOT > PPY > PANI. High specific capacities and excellent cycle life were demonstrated for sulfur cathodes made from these conductive polymer-coated hollow sulfur nanospheres. PMID:24127640

Li, Weiyang; Zhang, Qianfan; Zheng, Guangyuan; Seh, Zhi Wei; Yao, Hongbin; Cui, Yi

2013-01-01

398

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

399

Hydration of pure and base-Containing sulfuric acid clusters studied by computational chemistry methods  

NASA Astrophysics Data System (ADS)

The formation of hydrates of small molecular sulfuric acid clusters and cluster containing both sulfuric acid and base (ammonia or dimethylamine) has been studied by means of computational chemistry. Using a combined ab initio/density functional approach, formation energies of clusters with up to four sulfuric acid molecules, and up to two base molecules, have been calculated. Consequences for the hydration level of the corresponding clusters have been modelled. While the majority of pure sulfuric acid cluster are comparatively strongly hydrated, base containing cluster were found to be less hydrophilic. Dimethylamine is particularly effective in lowering the hydrophilicity of the cluster. Implications of the hydration profiles on atmospheric processes are discussed.

Henschel, Henning; Ortega, Ismael K.; Kupiainen, Oona; Olenius, Tinja; Kurtn, Theo; Vehkamki, Hanna

2013-05-01

400

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

SciTech Connect

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

Frost, J.W.

1991-12-31

401

Photopolymerization and Mass-Independent Sulfur Isotope Fractionations in Carbon Disulfide  

PubMed

Irradiation of gaseous carbon disulfide [CS2(g)] at 313 nanometers produces a dark brown aerosol of (CS2)x. Its thermal decomposition products include disulfur (S2), carbon monosulfide (CS), and (CS)x. The photopolymerization process is accompanied by a large mass-independent isotopic fractionation of sulfur (a 5 to 10 per mil sulfur-33 excess and a 61 to 84 per mil sulfur-36 deficit). Excess sulfur-33 has been observed in several classes of meteorites. Photochemical production of (CS2)x may be important in the origin and evolution of cosmochemical environments such as the presolar nebula, meteorites, asteroids, and planetary atmospheres. PMID:8670412

Colman; Xu; Thiemens; Trogler

1996-08-01

402

Photopolymerization and Mass-Independent Sulfur Isotope Fractionations in Carbon Disulfide  

NASA Astrophysics Data System (ADS)

Irradiation of gaseous carbon disulfide [CS2(g)] at 313 nanometers produces a dark brown aerosol of (CS_2)_x. Its thermal decomposition products include disulfur (S_2), carbon monosulfide (CS), and (CS)_x. The photopolymerization process is accompanied by a large mass-independent isotopic fractionation of sulfur (a 5 to 10 per mil sulfur-33 excess and a 61 to 84 per mil sulfur-36 deficit). Excess sulfur-33 has been observed in several classes of meteorites. Photochemical production of (CS_2)_x may be important in the origin and evolution of cosmochemical environments such as the presolar nebula, meteorites, asteroids, and planetary atmospheres.

Colman, Jonah J.; Xu, Xianping; Thiemens, Mark H.; Trogler, William C.

1996-08-01

403

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

404

Hydrogen and sulfur recovery from hydrogen sulfide wastes  

DOEpatents

A process is described for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is [dis]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, J.B.L.; Gorski, A.J.; Daniels, E.J.

1993-05-18

405

Control of Sulfur Dioxide Emissions from Copper Smelters: Volume II. Hydrogen Sulfide Production from Copper Concentrates.  

National Technical Information Service (NTIS)

A laboratory investigation has been made of a modified copper smelting process which provides a solution to the sulfur dioxide air pollution problem. Preliminary economic evaluation of the process appears favorable with good prospects for further improvem...

C. A. Rohrmann H. T. Fullam

1974-01-01

406

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

PubMed Central

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

2012-01-01

407

ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY  

SciTech Connect

This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500C to 700C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent durability was indicated in a twenty-five-cycle test. The sorbent was exposed for 58 consecutive days to temperatures between 600C and 800C and gas atmospheres from highly reducing to highly oxidizing without measurable loss of sulfur capacity or reactivity. In the process analysis phase of this study, a two-stage desulfurization process using cerium sorbent with SO2 regeneration followed by zinc sorbent with dilute O2 regeneration was compared to a single-stage process using zinc sorbent and O2 regeneration with SO2 in the regeneration product gas converted to elemental sulfur using the direct sulfur recovery process (DSRP). Material and energy balances were calculated using the process simulation package PRO/II. Major process equipment was sized and a preliminary economic analysis completed. Sorbent replacement rate, which is determined by the multicycle sorbent durability, was found to be the most significant factor in both processes. For large replacement rates corresponding to average sorbent lifetimes of 250 cycles or less, the single-stage zinc sorbent process with DSRP was estimated to be less costly. However, the cost of the two-stage cerium sorbent process was more sensitive to sorbent replacement rate, and, as the required replacement rate decreased, the economics of the two-stage process improved. For small sorbent replacement rates corresponding to average sorbent lifetimes of 1000 cycles or more, the two-stage cerium process was estimated to be less costly. In the relatively wide middle range of sorbent replacement rates, the relative economics of the two processes depends on other factors such as the unit cost of sorbents, oxygen, nitrogen, and the relative capital costs.

A. LOPEZ ORTIZ; D.P. HARRISON; F.R. GROVES; J.D. WHITE; S. ZHANG; W.-N. HUANG; Y. ZENG

1998-10-31

408

Maturation of cytosolic and nuclear iron-sulfur proteins.  

PubMed

Eukaryotic cells contain numerous cytosolic and nuclear iron-sulfur (Fe/S) proteins that perform key functions in metabolic catalysis, iron regulation, protein translation, DNA synthesis, and DNA repair. Synthesis of Fe/S clusters and their insertion into apoproteins are essential for viability and are conserved in eukaryotes. The process is catalyzed in two major steps by the CIA (cytosolic iron-sulfur protein assembly) machinery encompassing nine known proteins. First, a [4Fe-4S] cluster is assembled on a scaffold complex. This step requires a sulfur-containing compound from mitochondria and reducing equivalents from an electron transfer chain. Second, the Fe/S cluster is transferred from the scaffold to specific apoproteins by the CIA targeting complex. This review summarizes our molecular knowledge on CIA protein function during the assembly process. PMID:24314740

Netz, Daili J A; Mascarenhas, Judita; Stehling, Oliver; Pierik, Antonio J; Lill, Roland

2014-05-01

409

The sulfur-iodine thermochemical water-splitting cycle  

NASA Astrophysics Data System (ADS)

Experimental work was carried out on process improvement concepts, resulting in an advanced process for treatment of the lower phase (H2O-HI-I2) and a liquid HI decomposition process utilizing homogeneous catalysis. Bench scale testing of design improvements was successfully carried out. A flowsheet for a solar thermal powered sulfur iodine water splitting process was developed and a cost estimate for hydrogen production completed.

Besenbruch, G. E.; Norman, J. H.; Brown, L. C.; Okeefe, D. R.; Endo, M.; Allen, C. L.

1982-12-01

410

LASL thermochemical hydrogen program status on October 31, 1977. [Cycles using sulfuric acid as an intermdiate  

Microsoft Academic Search

The LASL Hydrogen Program is continuing its investigation of practical schemes to decompose water thermochemically for hydrogen production. Efforts were and are being devoted to process improvements in cycles that use sulfuric acid as an intermediate. Sulfuric acid-hydrogen bromide cycles are being studied as a means of overcoming the heat penalty in drying acid solutions. An alternate approach involves the

K. E. Cox; M. G. Bowman

1977-01-01

411

Bioenergetic studies of sulfur reduction in the hyperthermophilic archaebacteria Pyrodictium brockii and Pyrococcus furiosus  

Microsoft Academic Search

The central focus of this work was the investigation of the central energy generating pathways of two hyperthermophilic sulfidogenic archaebacteria, Pyrodictium brockii and Pyrococcus furiosus. A potential application of these organisms in the desulfurization of coals was investigated. An effective ;means of removing elemental sulfur (S[degrees]) was developed. Analytical and processing applications are discussed. The rates of sulfur removal by

Schicho

1992-01-01

412

Sulfur polymer cement as a low-level waste glass matrix encapsulant.  

National Technical Information Service (NTIS)

Sulfur polymer cement (SPC) is being considered as a matrix encapsulant for the Hanford low-level (activity) waste glass. SPC is an elemental sulfur polymer-stabilized thermoplastic that is fluid at 120 (degrees)C to 140(degrees)C. The candidate process w...

P. Sliva Y. B. Peng D. K. Peeler

1996-01-01

413

Understanding the effects of sulfur on mercury capture from coal-fired utility flue gases  

Microsoft Academic Search

Coal combustion continues to be a major source of energy throughout the world and is the leading contributor to anthropogenic mercury emissions. Effective control of these emissions requires a good understanding of how other flue gas constituents such as sulfur dioxide (SO2) and sulfur trioxide (SO3) may interfere in the removal process. Most of the current literature suggests that SO2

Eric A. Morris; Kazuki Morita; Charles Q. Jia

2010-01-01

414

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

415

Volcanogenic Sulfur on Earth and Io: Composition and Spectroscopy  

USGS Publications Warehouse

The causes of Io's variegated surface, especially the roles of sulfur, and the geochemical history of sulfur compounds on Io are not well understood. Suspecting that minor impurities in sulfur might be important, we have investigated the major and trace element chemistry and spectroscopic reflectance of natural sulfur from a variety of terrestrial volcanic-hydrothermal environments. Evidence suggests that Io may be substantially coated with impure sulfur. On Earth, a few tenths of a percent to a few percent of chalcophile trace elements (e.g., As and Se) comonly occur in sulfur and appear to stabilize material of yellow, brown, orange, and red hues, which may persist even at low temperatures. Percentage levels of chalcophile impurities are reasonably expected to occur on Io in vapor sublimate deposits and flows derived from such deposits. Such impurities join a host of other mechanisms that might explain Io's reds and yellows. Two-tenths to two percent opaque crystalline impurities, particularly pyrite (FeS2), commonly produces green, gray, and black volcanic sulfur on Earth and might explain areas of Io having deposits of these colors. Pyrite produces a broad absorption near 1 ??m that gradually diminishes out to 1.6 ??m - similar but not identical to the spectrum of Io seen in Galileo NIMS data. Percentage amounts of carbonaceous impurities and tens of percent SiO2 (as silicates) also strongly affect the spectral properties of Earth's sulfur. Io's broad absorption between 0.52 and 0.64 ??m remains unexplained by these data but could be due to sodium sulfides, as suggested previously by others, or to As, Se, or other impurities. These impurities and others, such as P and Cl (which could exist on Io's surface in amounts over 1% that of sulfur), greatly alter the molecular structure of molten and solid sulfur. Minor impurities could impact Io's geology, such as the morphology of sulfur lava flows and the ability of sulfur to sustain high relief. We have not found any natural sulfur containing significant Na beyond that attributable to silicate inclusions. In sum, the unique physical-chemical properties of S-rich systems and the strong affinity of certain elements for S may have broad implications for the appearance, spectroscopic interpretation, and geologic processes of Io. Identification of impurities in sulfur may be helpful in tracing the geochemical evolution of surface deposits on Io. Perhaps foretelling of new areas of investigation, Cl has recently been reported in the Io torus (M. Kueppers and N. M. Schneider 1999, Eos Trans.80, 5207), suggesting the presence on Io of either salts, such as halite, or sulfur chlorides. Further evidence of minor iogenic impurities should be sought in Io's neutral cloud and plasma torus as well as in further scrutiny of Io's reflectance spectra. ?? 1999 Academic Press.

Kargel, J. S.; Delmelle, P.; Nash, D. B.

1999-01-01

416

Sulfur capture in combination bark boilers  

SciTech Connect

A review of sulfur dioxide emission data for eight combination bark boilers in conjunction with the sulfur contents of the fuels reveals significant sulfur capture ranging from 10% to over 80% within the solid ash phase. Wood ash characteristics similar to activated carbon as well as the significant wood ash alkali oxide and carbonate fractions are believed responsible for the sulfur capture. Sulfur emissions from combination bark-fossil fuel firing are correlated to the sulfur input per ton of bark or wood residue fired.

Someshwar, A.V.; Jain, A.K. (National Council of the Paper Industry for Air and Stream Improvement, Gainesville, FL (United States))

1993-07-01

417

Images of Jupiter's Sulfur Ring.  

PubMed

Images of the ring of singly ionized sulfur encircling Jupiter obtained on two successive nights in April 1979 show that the ring characteristics may change dramatically in approximately 24 hours. On the first night the ring was narrow and confined to the magnetic equator inside Io's orbit. On the second it was confined symmetrically about the centrifugal symmetry surface and showed considerable radial structure, including a "fan" extending to Io's orbit. Many of the differences in the ring on the two nights can be explained in terms of differences in sulfur plasma temperature. PMID:17809102

Pilcher, C B

1980-01-11

418

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

419

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

420

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

SciTech Connect

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

Miller, K.W.

1994-09-01

421

Standard test method for trace quantities of total sulfur (Wickbold and Beckman combustion apparatus)  

SciTech Connect

This method covers the determination of total sulfur primarily in the range from 2 to 25 ppM in volatile, normally liquid organic materials. The method may be extended to liquid materials with higher sulfur concentration and to viscous liquids and solids by using appropriate solvents. Samples should not contain more than 100 ppM of halogens, 2 ppM of barium, or 0.1 ppM of lead or appreciable ashforming substances. For the determination of total sulfur in liquefied petroleum gases see ASTM Method D 2784, Test f