Reaction between hydrogen sulfide and zinc oxide-titanium oxide sorbents. 1. Single-pellet kinetic studies

Woods, Mark; Gangwal, S.K.; Jothimurugesan, K.; Harrison, Douglas P.

doi:10.1021/ie00103a012

Cited by 89 publications

(80 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of metals including Zn, Fe, Mn, Cu, and Ca have been studied but most of the recent research has focused on Zn-based materials, including ZnO (e.g., Gibson and Harrison 1980), ZnFe 2 O 4 (e.g., Focht et al 1988), and xZnO•TiO 2 (e.g., Woods et al 1990). …”

Section: High Temperature Gas Desulfurizationmentioning

confidence: 99%

High Efficiency Desulfurization of Synthesis Gas

Mukherjee¹,

Yi²,

Podlaha³

et al. 2001

View full text Add to dashboard Cite

Mixed metal oxides containing CeO 2 and ZrO 2 are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv of less H 2 S. The research is justified by recent results in this laboratory that showed that reduced CeO 2 , designated CeO n (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO 2 has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO 2 , and should have similar beneficial effects on CeO 2 desulfurization sorbents.An electrochemical method for synthesizing CeO 2 -ZrO 2 has been developed and the products have been characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO 2 have been prepared. XRD showed the product to be a solid solution at low ZrO 2 contents with a separate ZrO 2 phase emerging at higher ZrO 2 levels. Phase separation did not occur when the solid solutions were heat treated at 700 o C.A flow reactor system constructed of quartz and teflon has been constructed, and a gas chromatograph equipped with a pulsed flame photometric detector (PFPD) suitable for measuring sub-ppmv levels of H2S has been purchased with LSU matching funds. Preliminary desulfurization tests using commercial CeO 2 and CeO 2 -ZrO 2 in highly reducing gas compositions has confirmed that CeO 2 -ZrO 2 is more effective than CeO 2 in removing H 2 S. At 700 o C the product H 2 S concentration using CeO 2 -ZrO 2 sorbent was near the 0.1 ppmv PFPD detection limit during the prebreakthrough period.ii EXECUTIVE SUMMARYThe recently released DOE Vision 21 program requires much more stringent control of H 2 S concentration in coal-derived synthesis gas. Previous target levels of about 20 ppmv H 2 S suitable for electric power generation using an integrated gasification combined cycle process (IGCC) have been replaced by H 2 S targets of 1 ppmv or less required for fuel cell and other catalytic processes.Zinc-based sorbents developed for IGCC applications are not capable of achieving the Vision 21 target at high temperatures. Reduced cerium oxide, CeO n (1.5 < n < 2.0) has recently been shown to be capable of reducing H 2 S to less than 1ppmv at temperatures near 700 o C, but only in gas atmospheres having considerable greater reducing power than typical coal-derived gases. Related research in oxidation catalysis and three-way automotive catalysis has shown that performance has been improved by the addition of ZrO 2 to the CeO 2 . The reasons given for the improved performance, including increased oxygen exchange capacity, should also result in improved desulfurization performance.This research project consists of two major activities -the electrochemical synthesis and characterization of CeO 2 -ZrO 2 materials, and high temperature desulfurization tests using CeO 2 -ZrO 2 sorbents. Nanocrystalline powders of approximately 5 nm grain diameter and containin...

show abstract

Section: High Temperature Gas Desulfurizationmentioning

confidence: 99%

High Efficiency Desulfurization of Synthesis Gas

Mukherjee¹,

Yi²,

Podlaha³

et al. 2001

View full text Add to dashboard Cite

show abstract

“…Because of zinc oxide's potential for reduction (ZnO + H 6 Zn + H O) at >600EC followed by evaporation, a zinc oxide-titanium oxide sorbent, namely 2 2 zinc titanate sorbent, was developed and tested at high temperature and high pressure (Gangwal et al, 1988;Jothimurugesan and Harrison, 1990;Stephanpoulos and Jothimurugesan, 1990;Woods et al, 19990;1991). Zinc titanate is currently one of the leading sorbents.…”

Section: IVmentioning

confidence: 99%

Scale-Up of Advanced Hot-Gas Desulfurization Sorbents

Jothimurugesan¹,

Gangwal²

1998

View full text Add to dashboard Cite

Hot-Gas Desulfurization (HGD) of fuel gas in integrated gasification combined cycle (IGCC) power systems has received a great deal of attention over the past two decades due to the potential for high thermal efficiency (up to 47 %) and low environmental impact of these advanced power systems using HGD. In an IGCC system coal is gasified at elevated pressures, typically 20 to 30 atm, to produce a low-volume fuel gas which is desulfurized prior to burning in a combustion turbine to produce electricity. Higher efficiency and lower cost are achieved by efficient integration of modular designs of the gasification, hot-gas cleanup, and turbine subsystems. Gas cleaning primarily involves removal of particulates and sulfur compounds -mostly H S and some carbonyl sulfide (COS). Sorbents based on zinc oxide, 2 currently the leading candidates, can effectively reduce the H S in coal gas to around 10 ppm 2 levels and can be regenerated for multicycle operation. However, all current first-generation leading sorbents undergo significant loss of sulfidation reactivity and capacity with cycling, as much as 50 % or greater loss in only 25-50 cycles. Stability of the hot-gas desulfurization sorbents over at least one hundred cycles is essential for improved IGCC economics over conventional power plants.iv The objective of this study was to develop advanced regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective was to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high sulfidation activity at temperatures as low as 343 C (650 F).

show abstract

“…Removal of H2S using zinc-based sorbents, particularly zinc titanate, to < 20 ppmv levels has been well established (Lew et al, 1989;Jothimurugesan and Harrison, 1990;Woods et al, 1990;Gupta and Gangwal, 1993,). Previous literature study indicated that catalyst have high activities for NH, decomposition (Knshnan et al, 1988).…”

Section: Disclaimermentioning

confidence: 99%

Simultaneous removal of H{sub 2}S and NH{sub 3} in coal gasification process. Quarterly progress report, October 1--December 31, 1994

Jothimurugesan¹,

Adeyiga²,

Gangwal³

1995

Self Cite

View full text Add to dashboard Cite

DOE Project OfficerReporting Period OBJECTIVESThe objective of this study is to develop advanced high-temperature coal gas desulhrization mixed-metal oxide sorbents with stable ammonia decomposition materials at 550-800" C ( 1022-1472" F). The specific objectives of the project are to:(i) Develop a combined sorbent-catalyst materials shall be capable of removing hydrogen sulfide to less than 20 ppmv and ammonia by at least 90 percent.(ii) Carry out comparative fixed-bed studies of absorption and regeneration with various formulations of sorbent-catalyst systems and select most promising sorbent-catalyst type.(iii) Conduct long-term (at least 30 cycles) durability and chemical reactivity in the fixed-bed with the superior sorbent-catalyst. BACKGROUND INFORMATION

show abstract

Reaction between hydrogen sulfide and zinc oxide-titanium oxide sorbents. 1. Single-pellet kinetic studies

Cited by 89 publications

References 7 publications

High Efficiency Desulfurization of Synthesis Gas

High Efficiency Desulfurization of Synthesis Gas

Scale-Up of Advanced Hot-Gas Desulfurization Sorbents

Simultaneous removal of H{sub 2}S and NH{sub 3} in coal gasification process. Quarterly progress report, October 1--December 31, 1994

Contact Info

Product

Resources

About