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Durable Zinc Oxide Containing Regenerable Desulfurization Sorbents For Both Low And High Temperature Applications
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Book Synopsis Durable Zinc-Oxide-Containing Regenerable Desulfurization Sorbents for Both Low- and High-Temperature Applications by : Ranjani V. Siriwardane
Download or read book Durable Zinc-Oxide-Containing Regenerable Desulfurization Sorbents for Both Low- and High-Temperature Applications written by Ranjani V. Siriwardane and published by . This book was released on 2000 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 2001 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fixed-bed regenerable desulfurization sorbent, identified as RVS-land 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. This testing has demonstrated that 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 high crush strength and attrition resistance, which, unlike past sorbent formulations, does not decrease with extended testing at actual at operating conditions. The sulfur capacity of the sorbent is roughly 17 to 20 wt.% and also remains 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. 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 number of commercial tests involving RVS-1 have been either conducted or are planned in the near future. The RVS-1 sorbent has been tested by Epyx, Aspen Systems and McDermott Technology (MTI), Inc for desulfurization of syngas produced by reforming of hydrocarbon liquid feedstocks for fuel cell applications. The RVS-1 sorbent was selected by MTI over other candidate sorbents for demonstration testing in their 500-kW ship service fuel cell program. It was also possible to obtain sulfur levels in the ppbv range with the modified RVS-1 sorbent.
Book Synopsis Durable Zinc Oxide-containing Sorbents for Coal Gas Desulfurization by :
Download or read book Durable Zinc Oxide-containing Sorbents for Coal Gas Desulfurization written by and published by . This book was released on 1994 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel as a matrix material, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.
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.
Download or read book Spokane's Golden Jubilee written by and published by . This book was released on 1931 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fuel Cells: Technologies for Fuel Processing by : Dushyant Shekhawat
Download or read book Fuel Cells: Technologies for Fuel Processing written by Dushyant Shekhawat and published by Elsevier. This book was released on 2011-03-18 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel Cells: Technologies for Fuel Processing provides an overview of the most important aspects of fuel reforming to the generally interested reader, researcher, technologist, teacher, student, or engineer. The topics covered include all aspects of fuel reforming: fundamental chemistry, different modes of reforming, catalysts, catalyst deactivation, fuel desulfurization, reaction engineering, novel reforming concepts, thermodynamics, heat and mass transfer issues, system design, and recent research and development. While no attempt is made to describe the fuel cell itself, there is sufficient description of the fuel cell to show how it affects the fuel reformer. By focusing on the fundamentals, this book aims to be a source of information now and in the future. By avoiding time-sensitive information/analysis (e.g., economics) it serves as a single source of information for scientists and engineers in fuel processing technology. The material is presented in such a way that this book will serve as a reference for graduate level courses, fuel cell developers, and fuel cell researchers. - Chapters written by experts in each area - Extensive bibliography supporting each chapter - Detailed index - Up-to-date diagrams and full colour illustrations
Book Synopsis Advanced Hot-Gas Desulfurization Sorbents by :
Download or read book Advanced Hot-Gas Desulfurization Sorbents written by and published by . This book was released on 1997 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrated gasification combined cycle (IGCC) power systems are being advanced worldwide for generating electricity from coal due to their superior environmental performance, economics, and efficiency in comparison to conventional coal-based power plants. Hot gas cleanup offers the potential for higher plant thermal efficiencies and lower cost. A key subsystem of hot-gas cleanup is hot-gas desulfurization using regenerable sorbents. Sorbents based on zinc oxide are currently the leading candidates and are being developed for moving- and fluidized- bed reactor applications. Zinc oxide sorbents can effectively reduce the H2S in coal gas to around 10 ppm levels and can be regenerated for multicycle operation. However, all current first-generation leading sorbents undergo significant loss of reactivity with cycling, as much as 50% or greater loss in only 25-50 cycles. Stability of the hot-gas desulfurization sorbent over 100's of cycles is essential for improved IGCC economics over conventional power plants. This project aims to develop hot-gas cleanup sorbents for relatively lower temperature applications, 343 to 538°C with emphasis on the temperature range from 400 to 500°. Recent economic evaluations have indicated that the thermal efficiency of IGCC systems increases rapidly with the temperature of hot-gas cleanup up to 350°C and then very slowly as the temperature is increased further. This suggests that the temperature severity of the hot-gas cleanup devices can be reduced without significant loss of thermal efficiency. The objective of this study is to develop attrition-resistant advanced hot-gas desulfurization sorbents which show stable and high sulfidation reactivity at 343°C (650°F) to 538°C(1OOO°F) and regenerability at lower temperatures than leading first generation sorbents.
Book Synopsis Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications. Option 2 Program by :
Download or read book Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications. Option 2 Program written by and published by . This book was released on 1993 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most advantageous configurations of the integrated gasification combined cycle (IGCC) power system is coupling it with a hot gas cleanup for the more efficient production of electric power in an environmentally acceptable manner. In conventional gasification cleanup systems, closely heat exchangers are necessary to cool down the fuel gases for cleaning, sometimes as low as 200--300°F, and to reheat the gases prior to injection into the turbine. The result is significant losses in efficiency for the overall power cycle. High-temperature coal gas cleanup in the IGCC system can be operated near 1000°F or higher, i.e., at conditions compatible with the gasifier and turbine components, resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for IGCC power systems in which mixed-metal oxides are currently being used as desulfurization sorbents. The objective of this contract is to identify and test fabrication methods and sorbent chemical compositions that enhance the long-term chemical reactivity and mechanical durability of zinc ferrite and other novel sorbents for moving-bed, high-temperature desulfurization of coal-derived gases. Zinc ferrite was studied under the base program of this contract. In the next phase of this program novel sorbents, particularly zinc titanate-based sorbents, are being studied under the remaining optional programs. This topical report summarizes only the work performed under the Option 2 program. In the course of carrying out the program, more than 25 zinc titanate formulations have been prepared and characterized to identify formulations exhibiting enhanced properties over the baseline zinc titanate formulation selected by the US Department of Energy.
Book Synopsis Development of Advanced Hot-gas Desulfurization Sorbents. Final Report by :
Download or read book Development of Advanced Hot-gas Desulfurization Sorbents. Final Report written by and published by . This book was released on 1997 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project was to develop hot-gas desulfurization sorbent formulations for relatively lower temperature application, with emphasis on the temperature range from 343--538 C. The candidate sorbents include highly dispersed mixed metal oxides of zinc, iron, copper, cobalt, nickel and molybdenum. The specific objective was to develop suitable sorbents, that would have high and stable surface area and are sufficiently reactive and regenerable at the relatively lower temperatures of interest in this work. Stability of surface area during regeneration was achieved by adding stabilizers. To prevent sulfation, catalyst additives that promote the light-off of the regeneration reaction at lower temperature was considered. Another objective of this study was to develop attrition-resistant advanced hot-gas desulfurization sorbents which show stable and high sulfidation reactivity at 343 to 538 C and regenerability at lower temperatures than leading first generation sorbents.
Book Synopsis Enhanced Durability of Desulfurization Sorbents for Fluidized-bed Applications by :
Download or read book Enhanced Durability of Desulfurization Sorbents for Fluidized-bed Applications written by and published by . This book was released on 1992 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: To extend the operating temperature range and further improve the durability of fluidizable sorbents, zinc titanate, another leading regenerable sorbent, was selected for development in the later part of this project. A number of zinc titanate formulations were prepared in the 50 to 300 [mu]m range using granulation and spray drying methods. Important sorbent preparation variables investigated included zinc to titanium ratio, binder type, binder amount, and various chemical additives such as cobalt and molybdenum. A number of sorbents selected on the basis of screening tests were subjected to bench-scale testing for 10 cycles at high temperature, high pressure (HTHP) conditions using the reactor system designed and constructed during the base program. This reactor system is capable of operation either as a 2.0 in. or 3.0 in. I.D. bubbling bed and is rated up to 20 atm operation at 871[degrees]C. Bench-scale testing variables included sorbent type, temperature (550 to 750[degrees]C), gas type (KRW or Texaco gasifier gas), steam content of coal gas, and fluidizing gas velocity (6 to 15 cm/s). The sorbents prepared by spray drying showed poor performance in terms of attrition resistance and chemical reactivity. On the other hand, the granulation method proved to be very successful. For example, a highly attrition-resistant zinc titanate formulation, ZT-4, prepared by granulation exhibited virtually no zinc loss and demonstrated a constant high reactivity and sulfur capacity over 10 cycles, i.e., approximately a 60 percent capacity utilization, with Texaco gas at 750[degrees]C, 15 cm/s fluidizing velocity and 15 atm pressure. The commercial potential of the granulation method for zinc titanate manufacture was demonstrated by preparing two 80 lb batches of sorbent with zinc to titanium mol ratios of 0.8 and 1.5.
Book Synopsis Desulfurization of Hot Coal Gas by : Aysel T. Atimtay
Download or read book Desulfurization of Hot Coal Gas written by Aysel T. Atimtay and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: Economic and environmental requirements for advanced power generating systems demand the removal of corrosive and other sulfurous compounds from hot coal gas. After a brief account of the world energy resources and an overview of clean coal technologies, a review of regenerable metal oxide sorbents for cleaning the hot gas is provided. Zinc oxide, copper oxide, calcium oxide, manganese oxide based as well as supported and mixed metal oxide sorbents are treated. Performance analysis of these sorbents, effects of various parameters on the desulfurization efficiency, kinetics of sulfidation and regeneration reactions, sulfiding and regeneration mechanisms are discussed. Two chapters present recent results in the direct production of elemental sulfur from regeneration or SO2-rich gases.
Book Synopsis Enhanced Durability of High-temperature Desulfurization Sorbents for Fluidized-bed Applications. [Zinc Titanate]. by :
Download or read book Enhanced Durability of High-temperature Desulfurization Sorbents for Fluidized-bed Applications. [Zinc Titanate]. written by and published by . This book was released on 1992 with total page 15 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 ferrite and zinc titanate sorbents to be employed for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluid-bed reactor. The sorbent formulation specified for study during the base period of this project was zinc ferrite. Zinc titanate sorbents are being studied under two options to the base contract. Specific objectives of the zinc titanate sorbent development work are the following: The effect of following process variables was investigated o the performance of zinc titanate sorbents: Method of sorbent preparation, Composition of fuel gas, Zn to Ti ratio of the sorbent, Sulfidation temperature, and Superficial gas velocity. The effect of first three variables has been covered in RTI's 1991 paper (Gupta and Gangwal, 1991b), while the effect of temperature and superficial gas velocity is described here.
Book Synopsis Bench-scale Testing of Novel High-temperature Desulfurization Sorbents by :
Download or read book Bench-scale Testing of Novel High-temperature Desulfurization Sorbents written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Extrudates of regenerable mixed-metal oxide sorbents including zinc ferrite, copper-modified zinc ferrite, zinc titanate, copper aluminate, copper-iron aluminate, and copper manganate were prepared and tested for their potential to remove hydrogen sulfide (H/sub 2/S) from coal gasifier gas in a high-temperature high-pressure (HTHP) fixed-bed reactor. The zinc containing sorbents were found to be more promising than those containing combinations of copper, aluminum, iron, and manganese. Reductions in H/sub 2/S concentration were achieved depending on sorbent, reactor temperature, and steam concentration. The copper-modified zinc ferrite sorbent reduced the H/sub 2/S concentration to less than 1 ppmv at up to 1100/degree/F with 20 volume % steam in the gas. The zinc ferrite sorbent showed no apparent loss in capacity over 15 sulfidation-regeneration cycles but underwent significant strength reduction in a coal-derived gas with 15% or less steam due to soot formation. Zinc titanate exhibited excellent strength and capacity retention at steam levels as low as 5% and temperatures as high as 1350/degree/F. 13 refs., 64 figs., 75 tabs.
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.
Book Synopsis Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications. Base Program by :
Download or read book Enhanced Durability of High-temperature Desulfurization Sorbents for Moving-bed Applications. Base Program written by and published by . This book was released on 1991 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this contract was to identify and test fabrication methods and sorbent chemical compositions that enhance the long-term chemical reactivity and mechanical strength of zinc ferrite and other novel sorbents for moving-bed, high-temperature desulfurization of coal-derived gases. Desired properties to be enhanced for moving-bed sorbent materials are: (1) high chemical reactivity (sulfur absorption rate and total sulfur capacity), (2) high mechanical strength (pellet crush strength and attrition resistance), and (3) suitable pellet morphology (e.g., pellet size, shape, surface area, and average specific pore volume). In addition, it is desired to maintain the sorbent properties over extended cyclic use in moving- bed systems.
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:
Book Synopsis Advanced Sorbent Development Program Development of Sorbents for Moving-Bed and Fluidized-Bed Applications by :
Download or read book Advanced Sorbent Development Program Development of Sorbents for Moving-Bed and Fluidized-Bed Applications written by and published by . This book was released on 2000 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 C (900-1000 F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 C (650 F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 C (650-1000 F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost assessment and a market plan for large-scale fabrication of sorbents were developed. As an optional task, long-term bench-scale tests of the best moving-bed sorbents were conducted. Starting from thermodynamic calculations, several metal oxides were identified for potential use as hot gas cleanup sorbents using constructed phase stability diagrams and laboratory screening of various mixed-metal oxide formulations. Modified zinc titanates and other proprietary metal oxide formulations were evaluated at the bench scale and many of them found to be acceptable for operation in the target desulfurization temperature range of 370 C (700 F) to 538 C (1000 F) and regeneration temperatures up to 760 C (1400 F). Further work is still needed to reduce the batch-to-batch repeatability in the fabrication of modified zinc titanates for larger scale applications. The information presented in this Volume 1 report contains the results of moving-bed sorbent development at General Electric's Corporate Research and Development (GE-CRD). A separate Volume 2 report contains the results of the subcontract on fluidized-bed sorbent development at the Institute of Gas Technology (IGT).
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