Download or read book Electrochemical Removal of H2S from Fuel Gas Streams written by Steven Ray Alexander and published by . This book was released on 1992 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Electrochemical Separation of H2S from Coal Gasification Process Streams Quarterly Progress Report January 1 1992 March 31 1992 written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide from coal gasification product streams through an electrochemical membrane is being developed. H2S is removed from the syn-gas stream, split into hydrogen, which enriches the syn-gas, and sulfur, which can be condensed from an inert gas sweep stream. The process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. The process is economically attractive by the lack of adsorbents and the lack of a Claus process for sulfur recovery. Research conducted during the present quarter is highlighted, with an emphasis on progress towards the goal of an economically viable H2S removal technology for use in coal gasification facilities providing polished fuel for co-generation coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. Polishing application of this technology to coal gasification synthesis gas has been demonstrated with H2S removals as high as 89.1% recorded. No successful runs with stainless steel housings have yet been achieved. However, since stoichiometric CO2 removal with stainless steel housings has been achieved, H2S removal is achievable.

Download or read book Electrochemical Removal of H2S from Fuel Gas written by Gas Research Institute and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Development work was performed on an electrochemical membrane separation (EMS) process capable of removing H2S from fuel or natural gas as part of the overall upgrading to pipeline quality natural gas. The separation process is based on the reduction of H2S to elemental sulfur and hydrogen across the surface in a single step rather than the conventional two-step absorption-conversion route. The EMS operates at near gasifier temperature and can therefore operate more thermally efficiently than aqueous or organic liquid processes.

Download or read book High Temperature Electrochemical Separation of H Sub 2 S from Coal Gasification Process Streams written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide from coal gasification product streams through an electrochemical membrane is being developed. H2S is removed from the syn-gas stream, split into hydrogen, which enriches the syn-gas, and sulfur, which can be condensed from an inert gas sweep stream. The process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. The process is economically attractive by the lack of adsorbents and the lack of a Claus process for sulfur recovery. Research conducted during the present quarter is highlighted, with an emphasis on progress towards the goal of an economically viable H2S removal technology for use in coal gasification facilities providing polished fuel for co-generation coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. Polishing application of this technology to coal gasification synthesis gas has been demonstrated with H2S removals as high as 89.1% recorded. No successful runs with stainless steel housings have yet been achieved. However, since stoichiometric CO2 removal with stainless steel housings has been achieved, H2S removal is achievable.

Download or read book High Temperature Electrochemical Separation of H2S from Coal Gasification Process Streams Quarterly Progress Report April 1 1992 June 30 1992 written by and published by . This book was released on 1992 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide from coal gasification product streams through an electrochemical membrane is being developed using the funds from this grant. H2S is removed from the syn-gas stream, split into hydrogen, which enriches the syn-gas, and sulfur, which can be condensed from an inert gas sweep stream. The process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. The process is economically attractive by the lack of adsorbents and the lack of a Claus process for sulfur recovery. Research conducted during the present quarter is here highlighted, with an emphasis on progress towards the goal of an economically viable H2S removal technology for use in coal gasification facilities providing polished fuel for co-generation coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities.

Download or read book High Temperature Electrochemical Polishing of H2S from Coal Gasification Process Stream Quarterly Progress Report January 1 1995 March 31 1995 written by and published by . This book was released on 1995 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide (H2S) from coal gasification product streams through an electrochemical membrane is being developed. H2S is removed from the syn-gas stream, split into hydrogen, which enriches the exiting syn-gas, and sulfur, which is condensed from an inert sweep gas stream. The process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. The process is made economically attractive by the lack of need for a Claus process for sulfur recovery. To this extent the project presents a novel concept for improving utilization of coal for more efficient power generation. Past experiments using this concept dealt with identifying removal of 1--2% H2S from gases containing only H2S in N2, simulated natural gas, and simulated coal gas. Data obtained from these experiments resulted in extended studies into electrode kinetics and electrode stability in molten melts. The most recent experiments evaluated the polishing application (removal Of H2S below 10 ppm) using the Electrochemical Membrane Separator (EMS). H2S removal efficiencies over 90% were achieved at these stringent conditions of low H2S concentrations proving the technologies polishing capabilities. Other goals include optimization of cell materials capable of improving cell performance. Once cell materials are defined, cell experiments determining maximum removal capabilities and current efficiencies will be conducted. Also, a model theoretically describing the preferred reduction of H2S, the transport of S2−, and the competing transport of CO2 will be investigated. The model should identify the maximum current efficiency for H2S removal, depending on variables such as flow rate, temperature, current application, and the total cell potential.

Download or read book High Temperature Electrochemical Polishing of H2S from Coal Gasification Process Streams written by and published by . This book was released on 1997 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Electrochemical Membrane Separator (E.M.S.), the focus of experimental work, purges a fuel gas contaminated with H2S. This is done by reducing the most electro-active species in the gas stream. In this case, H2S is reduced by the following: H2S + 2e− --> H2 + S2−. A membrane which contains sulfide ions in a molten salt electrolyte will act to transport the ions across to the anode. If the membrane is impermeable to H2 diffusion from the cathode side, an inert sweep gas can be used to carry the vaporous oxidized sulfur downstream to be condensed. S2−--> 1/2 S2 +2e−. Processes to remove H2S typically rely on low-to-ambient temperature adsorption, followed by sorbent regeneration and Claus plant treatment for conversion of H2S to a salable by-product, sulfur. Although effective, this type of removal is very process- intensive as well as energy-inefficient due to low temperature operation. Gasification streams generally range from 500°C - 1000°C, requiring cooling before and reheating after process gas sweetening. Although these technologies have proven capable of meeting H2S levels required by molten carbonate fuel cell systems, there are several disadvantages inherent to these processes. Alternative high temperature methods are presently available, but process drawbacks including morphological changes in catalytic beds or inefficient molten salt sorbent processes negate savings incurred through energy efficient removal temperatures. An electrochemical membrane separation system for removing H2S from coal gasification product streams is the subject of this investigation. The high operating temperature, flow-through design, and capability of selective H2S removal and direct production of elemental sulfur offered by this process provide several advantages over existing and developmental H2S removal technologies. 17 refs., 21 figs., 1 tab.

Download or read book High Temperature Electrochemical Separation of H2S from Coal Gasification Streams written by and published by . This book was released on 1994 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method of polishing coal synthesis gas by an electrochemical membrane operation is being perfected. The operation takes advantage of an electrochemical potential gradient rather than conventional techniques, separating the H2S from the coal gas stream, leaving only H2 to enrich the exiting fuel gases. Sulfur is the by-product that is carried away by a separate inert sweep gas and condensed downstream. The technology is attractive due to simplicity as well as economics. An analytical model describing the preferred reduction of H2S, the transport of S2−, and the competing transport of CO32− through the removal cell has continued. The main objective is the relation between cell polarization and current efficiency. This has been realized. Recent experiments have focused on removing 100 pm inlet H2S utilizing laboratory fabricated cobalt cathodes.

Download or read book Electrochemical Polishing of Hydrogen Sulfide from Coal Synthesis Gas written by and published by . This book was released on 1995 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process has been developed for the separation of H2S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. H2S is removed from the syn-gas by reduction to the sulfide ion and H at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syn-gas is enriched with the H2. Order-of-magnitude reductions in H2S have been repeatably recorded (100 ppm to 10 ppm H2S) on a single pass through the cell. This process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. Since there are no absorbents used, there is no absorption/regeneration step as with conventional technology. Elemental sulfur is produced as a by-product directly, so there is no need for a Claus process for sulfur recovery. This makes the process economically attractive since it is much less equipment intensive than conventional technology.

Download or read book High Temperature Electrochemical Polishing of H2S from Coal Gasification Process Streams Quarterly Progress Report January 1 1996 March 31 1996 written by and published by . This book was released on 1996 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal may be used to generate electrical energy by any of several processes, most of which involve combustion or gasification. Combustion in a coal-fired boiler and power generation using a steam- cycle is the conventional conversion method; however, total energy conversion efficiencies for this type of process are only slightly over 30%. Integration of a gas-cycle in the process (combined cycle) may increase the total conversion efficiency to 40%. Conversion processes based on gasification offer efficiencies above 50%. H2S is the predominant gaseous contaminant in raw coal gas. Problems arise due to the corrosive nature of H2S on metal components contained in these cycles. Because of this, H2S concentrations must be reduced to low levels corresponding to certain power applications. An advanced process for the separation of hydrogen sulfide (H2S) from coal gasification product streams through an electrochemical membrane is being developed using funds from this grant. Past experiments using this concept dealt with identifying removal of 1-2% H2S from gases containing only H2S in N2, simulated natural gas, and simulated coal gas. Other goals include optimization of cell materials capable of improving cell performance. Once cell materials are defined, cell experiments determining maximum removal capabilities and current efficiencies will be conducted. Also, a model theoretically describing the preferred reduction of H2S, the transport of S2−, and the competing transport of CO2 will be investigated. The model should identify the maximum current efficiency for H2S removal, depending on variables such as flow rate, temperature, current application, and the total cell potential. 21 refs., 10 figs., 9 tabs.

Download or read book High Temperature Electrochemical Separation of H2S from Coal Gasification Process Streams Quarterly Progress Report October 1 1991 December 31 1991 written by and published by . This book was released on 1991 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide from coal gasification product streams through an electrochemical membrane is being developed using the funds from this grant. H2S is removed from the syn-gas stream, split into hydrogen, which enriches the syn-gas, and sulfur, which can be condensed from an inert gas sweep stream. The process allows removal of H2S without cooling the gas stream and with neglible pressure loss through the separator. The process is economically attractive by the lack of adsorbents and the lack of a Claus process for sulfur recovery.

Download or read book High Temperature Electrochemical Polishing of H2S from Coal Gasification Process Streams Quarterly Progress Report October 1 1995 December 31 1995 written by and published by . This book was released on 1995 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide (H2S) from coal gasification product streams through an electrochemical membrane is being developed. H2S is removed from the syn-gas stream, split into hydrogen, which enriches the exiting syn-gas, and sulfur, which is condensed from an inert sweep gas stream. The process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. The process is made economically attractive by the lack of need for a Claus process for sulfur recovery. Membrane manufacturing coupled with full-cell experimentation was the primary focus this quarter. A tape-casted zirconia membrane was developed and utilized in one full-cell experiment (run 25); run 24 utilized a fabricated membrane purchased from Zircar Corporation. Results are discussed.

Download or read book HIGH TEMPERATURE REMOVAL OF H2S FROM COAL GASIFICATION PROCESS STREAMS USING AN ELECTROCHEMICAL MEMBRANE SYSTEM written by and published by . This book was released on 2003 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: A bench scale set-up was constructed to test the cell performance at 600-700 C and 1 atm. The typical fuel stream inlet proportions were 34% CO, 22% CO2, 35% H2, 8% H2O, and 450-2000 ppm H2S. The fundamental transport restrictions for sulfur species in an electrochemical cell were examined. Temperature and membrane thickness were varied to examine how these parameters affect the maximum flux of H2S removal. It was found that higher temperature allows more sulfide species to enter the electrolyte, thus increasing the sulfide flux across the membrane and raising the maximum flux of H2S removal. The results identify sulfide diffusion across the membrane as the rate-limiting step in H2S removal. The maximum H2S removal flux of 1.1 x 10-6 gmol H2S min−1 cm−2 (or 3.5 mA cm−2) was obtained at 650 C, with a membrane that was 0.9 mm thick, 36% porous, and had an estimated tortuosity of 3.6. Another focus of this thesis was to examine the stability of cathode materials in full cell trials. A major hurdle that remains in process scale-up is cathode selection, as the lifetime of the cell will depend heavily on the lifetime of the cathode material, which is exposed to very sour gas. Materials that showed success in the past (i.e. cobalt sulfides and Y{sub 0.9}Ca{sub 0.1}FeO3) were examined but were seen to have limitations in operating environment and temperature. Therefore, other novel metal oxide compounds were studied to find possible candidates for full cell trials. Gd2TiMoO-- and La{sub 0.7}Sr{sub 0.3}VO3 were the compounds that retained their structure best even when exposed to high H2S, CO2, and H2O concentrations.

Download or read book High Temperature Electrochemical Polishing of H2S from Coal Gasification Process Streams Quarterly Report October 1 December 31 1997 written by and published by . This book was released on 1998 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide from coal gasification streams through an electrochemical membrane is being perfected. H2S is removed from a synthetic gas stream, split into hydrogen, which enriches the existing syn-gas, and sulfur, which is condensed downstream from an inert sweep gas stream. The process allows for continuous removal of H2S without cooling the gas stream while allowing negligible pressure loss through the separator. Moreover, the process is economically attractive due to the elimination of the need for a Claus process for sulfur recovery. To this extent the project presents a novel concept for improving utilization of coal for more efficient power generation. This quarter's research focused on fabricating LiCoO2 electrodes and then utilizing them in full cell experiments at 650 C. The cathode showed inefficient porosity to allow mass transfer of the extremely dilute hydrogen sulfide to the electrolyte interface.

Download or read book High Temperature Electrochemical Separation of H2S from Coal Gasification Process Streams Quarterly Progress Report October 1 1993 December 31 1993 written by and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method of polishing coal synthesis gas by an electrochemical membrane operation is being perfected. The operation takes advantage of an electrochemical potential gradient rather than conventional techniques, separating the H2S from the coal gas stream, leaving only H2 to enrich the exiting fuel gases. Sulfur is the by-product that is carried away by a separate inert sweep gas and condensed downstream. The technology is attractive due to simplicity as well as economics when compared to alternatives. An analytical model describing the preferred reduction of H2S, the transport of S2−, and the competing transport of CO32− through the removal cell has continued. The main objective is the relation between cell polarization and current efficiency. This has been realized. Experiments this quarter focused on removing 100 ppM inlet H2S, utilizing laboratory fabricated cobalt cathodes.

Download or read book High Temperature Electrochemical Polishing of H2S from Coal Gasification Process Streams Quarterly Progress Report October 1 1996 December 31 1996 written by and published by . This book was released on 1996 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced process for the separation of hydrogen sulfide H2S from coal gasification product streams through an electrochemical membrane is developed using funds from this grant. H2S is removed from the syngas stream, split into hydrogen, which enriches the exiting syngas, and sulfur, which is condensed from an inert sweep gas stream. The process allows removal of H2S without cooling the gas stream and with negligible pressure loss through the separator. The process is made economically attractive by the lack of need of a Claus process for sulfur recovery. To this extent the project presents a novel concept for improving utilization of coal for more efficient power generation. This quarter focused on replacing the MACOR cell housings with stainless steel, which is more industrially suitable. Three runs were attempted this quarter, with successful results achieved in Run 34. The purpose of these experiments was: (1) test the electrochemical membrane separator's ability to concentrate CO2, (2) test the electrochemical membrane separator's ability to remove H2S; and (3) test stainless steel as an alternative cell housing to MACOR as well as test nickel cathode performance at the reduced temperature.

Download or read book H2S removal Processes for Low BTU Coal Gas written by M. S. Edwards and published by . This book was released on 1979 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: