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Title: Kinetics of MN based sorbents for hot coal gas. Quarterly report, September--December 1996

Abstract

Manganese-based sorbents have been investigated for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot coal gases prior to its use in combined cycle turbines. Four formulations of Mn-based sorbents were tested in an ambient-pressure fixed-bed reactor to determine steady state H{sub 2}S concentrations, breakthrough times and effectiveness of the sorbent when subjected to cyclic sulfidation and regeneration testing. In a previous report, the sulfidation results were presented. Manganese-based sorbents with molar ratios > 1:1 Mn:Substrate were effective in reducing the H{sub 2}S concentration in simulated coal gases to less than 100 ppmv over five cycles. Actual breakthrough time for formulation C6-2-1100 was as high as 73% of breakthrough time based on wt% Mn in sorbent. In this report, the regeneration results will be presented. Regeneration tests determined that loaded pellets can be fully regenerated in air/steam mixture at 750{degrees}C with minimal sulfate formation. 16 refs., 9 figs., 5 tabs.

Publication Date:
Research Org.:
Minnesota Univ., Minneapolis, MN (United States)
Sponsoring Org.:
USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
OSTI Identifier:
463546
Report Number(s):
DOE/PC/94212-T10
ON: DE97051627
DOE Contract Number:
FG22-94PC94212
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1996
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; ADSORBENTS; CHEMICAL REACTION KINETICS; COAL GAS; DESULFURIZATION; PROGRESS REPORT; MANGANESE COMPOUNDS; HYDROGEN SULFIDES; EXPERIMENTAL DATA

Citation Formats

NONE. Kinetics of MN based sorbents for hot coal gas. Quarterly report, September--December 1996. United States: N. p., 1996. Web. doi:10.2172/463546.
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NONE. Kinetics of MN based sorbents for hot coal gas. Quarterly report, September--December 1996. United States. doi:10.2172/463546.
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NONE. Tue . "Kinetics of MN based sorbents for hot coal gas. Quarterly report, September--December 1996". United States. doi:10.2172/463546. https://www.osti.gov/servlets/purl/463546.
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@article{osti_463546,
title = {Kinetics of MN based sorbents for hot coal gas. Quarterly report, September--December 1996},
author = {NONE},
abstractNote = {Manganese-based sorbents have been investigated for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot coal gases prior to its use in combined cycle turbines. Four formulations of Mn-based sorbents were tested in an ambient-pressure fixed-bed reactor to determine steady state H{sub 2}S concentrations, breakthrough times and effectiveness of the sorbent when subjected to cyclic sulfidation and regeneration testing. In a previous report, the sulfidation results were presented. Manganese-based sorbents with molar ratios > 1:1 Mn:Substrate were effective in reducing the H{sub 2}S concentration in simulated coal gases to less than 100 ppmv over five cycles. Actual breakthrough time for formulation C6-2-1100 was as high as 73% of breakthrough time based on wt% Mn in sorbent. In this report, the regeneration results will be presented. Regeneration tests determined that loaded pellets can be fully regenerated in air/steam mixture at 750{degrees}C with minimal sulfate formation. 16 refs., 9 figs., 5 tabs.},
doi = {10.2172/463546},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 31 00:00:00 EST 1996},
month = {Tue Dec 31 00:00:00 EST 1996}
}
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Technical Report:
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DOI:  10.2172/463546
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  • Manganese-based sorbents have been investigated for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot coal gases prior to its use in combined cycle turbines. Four formulations of Mn-based sorbents were tested in an ambient-pressure fixed-bed reactor to determine steady state H{sub 2}S concentrations, breakthrough times and effectiveness of the sorbent when subjected to cyclic sulfidation and regeneration testing. In a previous report, the sulfidation results were presented. Manganese-based sorbents with molar ratios > 1:1 Mn:Substrate were effective in reducing the H{sub 2}S concentration in simulated coal gases to less than 100 ppmv over five cycles. Actualmore » breakthrough time for formulation C6-2-1100 was as high as 73% of breakthrough time based on wt% Mn in sorbent. In this report, the regeneration results will be presented. Regeneration tests determined that loaded pellets can be fully regenerated in air/steam mixture at 750{degrees}C with minimal sulfate formation. 16 refs., 9 figs., 5 tabs.« less

  • Currently, the Morgantown Energy Technology Center, Department of Energy (DOE/METC) is actively investigating alternative hot fuel gas desulfurization sorbents for application to the Integrated Gasification Combined Cycle (IGCC). A sorbent must be highly active towards sulfur at high temperatures and pressures, and under varying degrees of reducing atmospheres. Also, it must regenerate nearly ideally to maintain activity over numerous cycles. Furthermore, regeneration must yield a sulfur product which is economically recoverable directly or indirectly. Several metal oxides have been investigated as regenerable sorbents for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot fuel gases. MnO wasmore » shown to have an intrinsic reaction rate approximately one order of magnitude greater than the rate or reaction with either CaO or ZnO and two orders of magnitude greater than the reaction rate with V{sub 2}0{sub 3}. Manganese also shows desulfurization potential in the temperature range of 600-700{degrees}C where metal oxides currently known to be reactive with H{sub 2}S are unsatisfactorily. In response to stability difficulties of single and binary metal oxide sorbents, increasing effort is being directed towards incorporation of an inert component into sorbent formulation as witnessed by the various Zn-titanates. Primarily, the inert component increases pore structure integrity while stabilizing the active metal oxide against reduction. This report will address testing of Mn-based sorbents in an ambient pressure fixed-bed reactor. Steady-state H{sub 2}S concentrations and breakthrough times will be presented.« less

  • ;
    Currently, the Morgantown Energy Technology Center, is actively investigating alternative hot fuel gas desulfurization sorbents for application to the Integrated Gasification Combined Cycle (IGCC). A sorbent must be highly active towards sulfur at high temperatures and pressure`s, and under varying degrees of reducing atmospheres. Thus, high conversion of the metal oxide and low hydrogen sulfide exit partial pressures. Also, it must regenerate nearly ideally to maintain activity over numerous cycles. Furthermore, regeneration must yield a sulfur product which is economically recoverable directly or indirectly. This cyclic process requires a holistic approach as any one criteria may eliminate a candidate sorbentmore » from further consideration. Over fifty induration campaigns have been conducted among the fifteens Mn-based sorbent formulations. All indurated sorbents has been tested for crush strength and chemical analysis. Also, fifteen sorbent formulations have been tested in a TGA for at least on e induration condition. Subsequently described are the three main groups of formulations tested. They are the MnCO{sub 3} supported with TiO{sub 2} (with or without bentonite), MnCO{sub 3} supported with Al{sub 2}O{sub 3} (with or without porosity enhancers), and MnO{sub 2} ore supported with alundum (with and without bentonite).« less

  • ;
    The Morgantown Energy Technology Center (METC) of the U.S. Department of Energy (DOE) is actively pursuing the development of reliable and cost-effective processes to clean coal gasifier gases for application to integrated gasification combined cycle (IGCC) and molten carbonate fuel cell (MCFC) power plants. A large portion of gas cleanup research has been directed towards hot gas desulfurization using Zn-based sorbents. However, zinc titanate sorbents undergo reduction to the metal at temperatures approaching 700{degrees}C and lose reactivity because of volatilization. In addition, sulfate formation during regeneration leads to spalling of reactive surfaces. Because of these problems with zinc-based sorbents, METCmore » has shown interest in formulating and testing manganese-based sorbents. Currently, many proposed IGCC processes include a water quench prior to desulfurization. This quench is required for two reasons; limitations in the process hardware (1000{degrees}C), and excessive Zn-based sorbent loss (about 700{degrees}C). With manganese, the water quench is not necessary to avoid sorbent loss, since Mn-based sorbents have been shown to retain reactivity under cyclic testing at 900{degrees}C. This advantage of manganese over zinc has potential to increase thermal efficiency as the trade-off of increasing the equilibrium H{sub 2}S over-pressure obtainable with a manganese sorbent. In the work which is reported here, lower loading temperatures (as low as 400{degrees}C) are studied. Also formulations containing titania rather then alumina are studied to attempt to improve performance.« less

  • Manganese ore as well as manganese carbonate, precipitated from aqueous solutions, combined with alumina to form indurated pellets hold promise of being a high-effective, inexpensive, regenerable sorbent for hot fuel gases. Although the thermodynamics for sulfur removal by manganese predicts somewhat higher hydrogen sulfide over-pressures (i.e. poorer degree of desulfurization) than can be accomplished with zinc-based sorbents, zinc tends to be reduced to the metallic state under coal gasification conditions resulting in loss of capacity and reactivity by volatilization of reactive surfaces. This volatilization phenomenon limits the temperatures for which desulfurization can be effectively accomplished to less than 550 Cmore » for zinc ferrite and 700 C for zinc titanate; whereas, manganese-based sorbents can be utilized at temperatures well in temperatures exceeding 700 C. Also the regeneration of manganese-based pellets under oxidizing conditions may be superior to that of zinc titanate since they can be loaded from a simulated reducing coal-derived gas and then be regenerated at higher temperatures (up to 1,300 C). The topics that will be addressed by this study include: preparation of an effective manganese-based sorbent; thermodynamics and kinetics of sulfur removal from hot fuel gases by this sorbent; analysis of kinetics and mechanisms by which sulfur is absorbed by the sorbent (i.e., whether by gaseous diffusion, surface-controlled reaction, or pore diffusion); and cyclic sulfidation and regeneration of the sorbent and recovery of the sulfur. 38 refs.« less