Regenerating a Long-Life Zinc Oxide-Based Sorbent for Moving Bed Reactors

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ISBN 13 :
Total Pages : 31 pages
Book Rating : 4.:/5 (113 download)

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Book Synopsis Regenerating a Long-Life Zinc Oxide-Based Sorbent for Moving Bed Reactors by : Robert J. Copeland

Download or read book Regenerating a Long-Life Zinc Oxide-Based Sorbent for Moving Bed Reactors written by Robert J. Copeland and published by . This book was released on 1998 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Long Life ZnO-TiO2 and Novel Sorbents

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ISBN 13 :
Total Pages : 13 pages
Book Rating : 4.:/5 (684 download)

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Book Synopsis Long Life ZnO-TiO2 and Novel Sorbents by :

Download or read book Long Life ZnO-TiO2 and Novel Sorbents written by and published by . This book was released on 1996 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combined cycles (combinations of a gas turbine and a steam bottoming cycle) are the most efficient power generation technology, while coal is the lowest cost fuel. Therefore, the combination of Coal Gasifiers and Combined Cycles is predicted to be the lowest cost source of baseload electric power in the next decade. In a GCC, the sulfur and particulates are removed from the gasifier gases before they enter the turbine combuster. While H2S (and COS/CS2) can be removed effectively by cooling hot gases down to near room temperature and scrubbing them with an aqueous amine solution, removing the H2S without cooling the gases (i.e., hot gas cleanup) is more advantageous. The leading hot gas sulfur absorbent uses a regenerable zinc oxide (ZnO) based sorbent, zinc titanate (Zn2TiO4 and/or ZnTiO3), to remove the H2S and other sulfur compounds from the hot coal gases. The zinc absorbs H2S, forming zinc sulfide (ZnS); ZnS is then regenerated with oxygen (air), releasing the sulfur as a concentrated stream of SO2. The SO2 can be converted into sulfuric acid, sulfur, or reacted with calcium carbonate to form calcium sulfate (gypsum). The sorbent may be operated in a fluidized bed reactor, transport reactor, or moving bed reactor. Both the fluidized-bed and the transport reactor use two separate reactors; one absorbs H2S COS and CS2 and converts the ZnO to ZnS; the second bed regenerates the sorbent with air converting the ZnS back to ZnO and producing SO2 (Figure 1); the sorbent moves between the two reactors to carry sulfur out of the absorber and return regenerated sorbent. Fluidized bed and transport reactors circulate very small particles at high gas velocity. The high gas-solid contact area of very small particles rapidly transfers both heat and mass within the reactor. The fluidized bed and transport reactor hot gas cleanup desulfurization systems are very similar and the sorbent particles are also of the same size (i.e., 50 to 400 micron). While there are several differences between the two reactors, the one which most affects the sorbent is the operation of the regenerator: fluidized bed reactors operate with diluted air while transport reactors operate with undiluted air.

Durable Zinc Oxide-Based Regenerable Sorbents for Desulfurization of Syngas in a Fixed-Bed Reactor

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Total Pages : 13 pages
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Book Synopsis Durable Zinc Oxide-Based Regenerable Sorbents for Desulfurization of Syngas in a Fixed-Bed Reactor by :

Download or read book Durable Zinc Oxide-Based Regenerable Sorbents for Desulfurization of Syngas in a Fixed-Bed Reactor written by and published by . This book was released on 2002 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fixed-bed regenerable desulfurization sorbent, identified as RVS-1 and developed by researchers at the U.S. Department of Energy's National Energy Technology Laboratory, was awarded the R & D 100 award in 2000 and is currently offered as a commercial product by Sued- Chemie Inc. An extensive testing program for this sorbent was undertaken which included tests at a wide range of temperatures, pressures and gas compositions both simulated and generated in an actual gasifier for sulfidation and regeneration. During these desulfurization tests, the RVS-1 sorbent maintained an effluent H2S concentration of 5 ppmv at temperatures from 260 to 600 C (500-1100 F) and pressures of 203-2026 kPa(2 to 20 atm) with a feed containing 1.2 vol% H2S. The types of syngas tested ranged from an oxygen-blown Texaco gasifier to biomass-generated syngas. The RVS-1 sorbent has demonstrated high crush strength and attrition resistance, which, unlike past sorbent formulations, does not decrease with extended testing at actual operating conditions. The sulfur capacity of the sorbent is roughly 17 to 20 wt.% which has been shown to remain constant during extended testing (25 cycles). In addition to H2S, the RVS-1 sorbent has also demonstrated the ability to remove dimethyl sulfide and carbonyl sulfide from syngas. It was also possible to obtain sulfur levels in the parts per billion by volume range with the modified RVS-1 sorbent. During regeneration, the RVS-1 sorbent has been regenerated with dilute oxygen streams (1 to 7 vol% O2) at temperatures as low as 370 C (700 F) and pressures of 304-709 kPa(3 to 7 atm). Although regeneration can be initiated at 370 C (700 F), regeneration temperatures in excess of 538 C (1000 F) were found to be optimal. The presence of steam, carbon dioxide or sulfur dioxide (up to 6 vol%) did not have any visible effect on regeneration or sorbent performance during either sulfidation or regeneration.

A Low Cost, Long Life Zinc Oxide Based Sorbent

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ISBN 13 :
Total Pages : 11 pages
Book Rating : 4.:/5 (113 download)

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Book Synopsis A Low Cost, Long Life Zinc Oxide Based Sorbent by : Robert J. Copeland

Download or read book A Low Cost, Long Life Zinc Oxide Based Sorbent written by Robert J. Copeland and published by . This book was released on 1996 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Durable Zinc Oxide Containing Sorbents for Moving Bed and Fluid-Bed Applications

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ISBN 13 :
Total Pages : 16 pages
Book Rating : 4.:/5 (395 download)

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Book Synopsis Durable Zinc Oxide Containing Sorbents for Moving Bed and Fluid-Bed Applications by : Ranjani V. Siriwardane

Download or read book Durable Zinc Oxide Containing Sorbents for Moving Bed and Fluid-Bed Applications written by Ranjani V. Siriwardane and published by . This book was released on 1998 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

A Long Life Zinc Oxide

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ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (113 download)

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Book Synopsis A Long Life Zinc Oxide by : Robert J. Copeland

Download or read book A Long Life Zinc Oxide written by Robert J. Copeland and published by . This book was released on 1995 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Chemical Abstracts

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ISBN 13 :
Total Pages : 2710 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Chemical Abstracts by :

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2710 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Highly Attrition Resistant Zinc Oxide-Based Sorbents for H2S Removal by Spray Drying Technique

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Total Pages : 5 pages
Book Rating : 4.:/5 (684 download)

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Book Synopsis Highly Attrition Resistant Zinc Oxide-Based Sorbents for H2S Removal by Spray Drying Technique by :

Download or read book Highly Attrition Resistant Zinc Oxide-Based Sorbents for H2S Removal by Spray Drying Technique written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Primary issues for the fluidized-bed/transport reactor process are high attrition resistant sorbent, its high sorption capacity and regenerability, durability, and cost. The overall objective of this project is the development of a superior attrition resistant zinc oxide-based sorbent for hot gas cleanup in integrated coal gasification combined cycle (IGCC). Sorbents applicable to a fluidized-bed hot gas desulfurization process must have a high attrition resistance to withstand the fast solid circulation between a desulfurizer and a regenerator, fast kinetic reactions, and high sulfur sorption capacity. The oxidative regeneration of zinc-based sorbent usually initiated at greater than 600 C with highly exothermic nature causing deactivation of sorbent as well as complication of sulfidation process by side reaction. Focusing on solving the sorbent attrition and regenerability of zinc oxide-based sorbent, we have adapted multi-binder matrices and direct incorporation of regeneration promoter. The sorbent forming was done with a spray drying technique that is easily scalable to commercial quantity.

Long Life Moving-Bed Zinc Titanate Sorbent

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Total Pages : pages
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Book Synopsis Long Life Moving-Bed Zinc Titanate Sorbent by :

Download or read book Long Life Moving-Bed Zinc Titanate Sorbent written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Development of Durable Mixed-metal Oxide Sorbents for High-temperature Desulfurization of Coal Gases in Moving-bed Reactors

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ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Development of Durable Mixed-metal Oxide Sorbents for High-temperature Desulfurization of Coal Gases in Moving-bed Reactors by :

Download or read book Development of Durable Mixed-metal Oxide Sorbents for High-temperature Desulfurization of Coal Gases in Moving-bed Reactors written by and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed-metal oxide sorbents, particularly zinc ferrite and zinc titanate, are being developed for use in hot gas cleanup of coal gas in the integrated gasification combined-cycle (IGCC). For the case of moving-bed systems, the pelletized sorbent moves between the absorber and regenerator as it absorbs H2S from coal gas and is regenerated under diluted air. Therefore a mechanically strong and chemically active sorbent is necessary for proper long-term operation of the system. These desired properties depend on the active components in the sorbent, the type and concentration of the binder material, and the sorbent preparation procedure. In the current program, several zinc titanate sorbent formulations have been prepared using a new rounding fabrication procedure, and varying the types of additives/binders (e.g., bentonite and molybdenum) and calcination temperature (1450-1800 °F, 788-982 °C). Comparison with baseline cylindrical formulations was made by measuring attrition resistance, crush strength, thermogravimetric reactivity and bench-scale reactor performance.

Fixed Bed Testing of Durable, Steam Resistant Zinc Oxide Containing Sorbents

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ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (683 download)

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Book Synopsis Fixed Bed Testing of Durable, Steam Resistant Zinc Oxide Containing Sorbents by :

Download or read book Fixed Bed Testing of Durable, Steam Resistant Zinc Oxide Containing Sorbents written by and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The US Department of Energy is currently developing Integrated Gasification combined Cycle (IGCC) systems for electrical power generation. It has been predicted that IGCC plants with hot gas cleanup will be superior to conventional pulverized coal-fired power plants in overall plant efficiency and environmental performance. Development of a suitable regenerable sorbent is a major barrier issue in the hot gas cleanup program for IGCC systems. This has been a challenging problem during the last 20 years, since many of the sorbents developed in the program could not retain their reactivity and physical integrity during repeated cycles of sulfidation and regeneration reactions. Two promising sorbents and (METC6), which were capable of sustaining their reactivity and physical integrity during repeated sulfidation/regeneration cycles, have been developed at the Morgantown Energy Technology Center (METC) during the past year. These sorbents were tested (sulfided) both in low-pressure (260 kPa/37.7 psia) and high-pressure (1034 kPa/150 psia) fixed-bed reactors at 538°C (1000°F) with simulated KRW coal gas. High-pressure testing was continued for 20 cycles with steam regeneration. There were no appreciable changes in sulfidation capacity of the sorbents during the 20-cycle testing. The crush strength of the sorbent actually improved after 20 cycles and there were no indications of spalling or any other physical deterioration of the sorbents. In testing to date, these sorbents exhibit better overall sulfur capture performance than the conventional sorbents.

A Kinetic Study of the Sulfidation-regeneration of Zinc Oxide Sorbent

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ISBN 13 :
Total Pages : 300 pages
Book Rating : 4.:/5 (361 download)

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Book Synopsis A Kinetic Study of the Sulfidation-regeneration of Zinc Oxide Sorbent by : Oreoluwa Abimbola Sofekun

Download or read book A Kinetic Study of the Sulfidation-regeneration of Zinc Oxide Sorbent written by Oreoluwa Abimbola Sofekun and published by . This book was released on 1996 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Bench-scale Testing of Fluidized-bed Sorbents -- ZT-4

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ISBN 13 :
Total Pages : pages
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Book Synopsis Bench-scale Testing of Fluidized-bed Sorbents -- ZT-4 by :

Download or read book Bench-scale Testing of Fluidized-bed Sorbents -- ZT-4 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc oxide-based mixed metal-oxide sorbents for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluidized-bed reactor. Specific objectives of this study are the following:[sm-bullet] Investigating various manufacturing methods to produce fluidizable zinc ferrite and zinc titanate sorbents in a particle size range of 50 to 400[mu]m; Characterizating and screening the formulations for chemical reactivity, attrition resistance, and structural properties; Testing selected formulations in an HTHP bench-scale fluidized-bed reactor to obtain an unbiased ranking of the promising sorbents; Investigating the effect of various process variables, such as temperature, nature of coal gas, gas velocity, and chemical composition of the sorbent, on the performance of the sorbent; Life-cycle testing of the superior zinc ferrite and zinc titanate formulations under HTHP conditions to determine their long-term chemical reactivity and mechanical strength; Addressing various reactor design issues; Generating a database on sorbent properties and performance (e.g., rates of reaction, attrition rate) to be used in the design and scaleup of future commercial hot-gas desulfurization systems; Transferring sorbent manufacturing technology to the private sector; Producing large batches (in tonnage quantities) of the sorbent to demonstrate commercial feasibility of the preparation method; and Coordinate testing of superior formulations in pilot plants with real and/or simulated coal gas.

Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications

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ISBN 13 :
Total Pages : 12 pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications by :

Download or read book Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications written by and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical reactivity was determined at GECRD by measuring sorbent sulfur loading (defined as grams of sulfur absorbed per 100 g of fresh sorbent) in fresh and in cycled samples from a bench-scale reactor. Only formulations that exhibited a good balance of chemical and mechanical performance as fresh pellets were selected for further cyclic testing in the benchscale reactor system. Details of the bench-scale reactor and procedures have been given before (Ayala, 1991). The important aspect of the benchscale testing is that both absorption and regeneration were conducted in a packed-bed reactor simulating the time/temperature environment to which the sorbent would be exposed in a typical cycle of the full-scale moving-bed system. Absorption was carried out at 1000[degrees]F using any of three gas compositions, all having a deliberately high H[sub 2]S concentration (1 %) to accelerate testing. The oxidative regeneration was carried out between 1000 and 1250[degrees]F and 1--21% oxygen during the early phases of regeneration, and at 1400[degrees]F during the final phase simulating the temperature rise of the sorbent bed. Sixteen zinc titanate formulations were prepared as cylindrical extrudates. For all formulations, the calcination time was held constant at 2 hours. The following results were obtained: Formulations containing a 0.8 Zn:Ti ratio produced mixtures of several stoichiometric titanates: Zn[sub 2]Ti[sub 3]O[sub 8], ZnTiO[sub 3], and Zn[sub 2]TiO[sub 4], with the relative amount of each depending on temperature. Formulations containing a 2.0 Zn:Ti ratio exhibited exclusively the Zn[sub 2]TiO[sub 4] structure. The higher calcination temperature of 1800[degrees]F significantly reduced the porosity available for chemical reactivity, while the lower calcination temperature of 1400[degrees]F produced, in some cases, formulations with traces of residual unreacted zinc oxide and anatase titanium dioxide.

Fluidized-bed Sorbents

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ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (873 download)

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Download or read book Fluidized-bed Sorbents written by and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc oxide-based mixed metal-oxide sorbents for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluidized-bed reactor. In this program, regenerable ZnO-based mixed metal-oxide sorbents are being developed and tested. These include zinc ferrite, zinc titanate, and Z-SORB sorbents. The Z-SORB sorbent is a proprietary sorbent developed by Phillips Petroleum Company (PPCo).

Energy Research Abstracts

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ISBN 13 :
Total Pages : 526 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis Energy Research Abstracts by :

Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-04 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Coal Abstracts

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ISBN 13 :
Total Pages : 880 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Coal Abstracts by :

Download or read book Coal Abstracts written by and published by . This book was released on 1993 with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt: