Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Get Book Here
Book Description
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.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Successful development of regenerable mixed-metal oxide sorbents for removal of reduced sulfur species (such as H[sub 2]S and COS) from coal-derived fuel gas streams at high=temperature, high-pressure (HTHP) conditions is a key to commercialization of the integrated-gasification-combined-cycle (IGCC) power systems. Among the various available coal-to-electricity pathways, IGCC power plants have the most potential with high thermal efficiency, simple system configuration, low emissions of SO[sub 2], NO[sub x] and other contaminants, modular design, and low capital cost. Due to these advantages, the power plants of the 21st century are projected to utilize IGCC technology worldwide. Sorbents developed for sulfur removal are primarily zinc oxide-based inorganic materials, because of their ability to reduce fuel gas sulfur level to a few parts-per-million (ppm). This project extends the prior work on the development of fluidizable zinc titanate particles using a spray-drying technique to impart high reactivity and attrition resistance. Specific objectives are to develop highly reactive and attrition-resistant zinc titanate sorbents in 40- to 150-[mu]m particle size range for transport reactor applications using semicommercial- to full commercial-scale spray dryers, to transfer sorbent production technology to private sector, and to provide technical support for Sierra Pacific's Clean Coal Technology Demonstration plant and METC's hot-gas desulfurization process development unit (PDU), both employing a transport reactor system.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
This project extends the prior work on the development of fluidizable zinc titanate particles using a spray-drying technique to impart high reactivity and attrition resistance. The specific objectives are: (1) To develop highly reactive and attrition-resistant zinc titanate sorbents in 40- to 150-[micro]m particle size range for transport reactor applications; (2) To transfer sorbent production technology to private sector; and (3) To provide technical support to Sierra Pacific Clean Coal Technology Demonstration plant and FETC's Hot-Gas Desulfurization Process Development Unit (PDU), both employing a transport reactor system.
Author: Dushyant Shekhawat
Publisher: Elsevier
ISBN: 0444535640
Category : Technology & Engineering
Languages : en
Pages : 569
Get Book Here
Book Description
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
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 101
Get Book Here
Book Description
Advanced integrated gasification combined cycle (IGCC) power systems require the development of high-temperature desulfurization sorbents capable of removing hydrogen sulfide from coal gasifier down to very low levels. The objective of this investigation was to identify and demonstrate methods for enhancing the long-term chemical reactivity and mechanical strength of zinc ferrite, a leading regenerable sorbent, for fluidized-bed applications. Fluidized sorbent beds offer significant potential in IGCC systems because of their ability to control the highly exothermic regeneration involved. However, fluidized beds require a durable, attrition-resistant sorbent in the 100--300 [mu]m size range. A bench-scale high-temperature, high- pressure (HTHP) fluidized-bed reactor (7.6-cm I.D.) system capable of operating up to 24 atm and 800°C was designed, built and tested. A total of 175 sulfidation-regeneration cycles were carried out using KRW-type coal gas with various zinc ferrite formulations. A number of sorbent manufacturing techniques including spray drying, impregnation, crushing and screening, and granulation were investigated. While fluidizable sorbents prepared by crushing durable pellets and screening had acceptable sulfur capacity, they underwent excessive attrition during multicycle testing. The sorbent formulations prepared by a proprietary technique were found to have excellent attrition resistance and acceptable chemical reactivity during multicycle testing. However, zinc ferrite was found to be limited to 550°C, beyond which excessive sorbent weakening due to chemical transformations, e.g., iron oxide reduction, was observed.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
Get Book Here
Book Description
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.
Author: Aysel T. Atimtay
Publisher: Springer Science & Business Media
ISBN: 9783540647263
Category : Nature
Languages : en
Pages : 432
Get Book Here
Book Description
Proceedings of the NATO Advanced Study Institute on Desulfurization of Hot Coal with Regenerable Metal Oxide Sorbents: New Developments, held in Kusadasi, Turkey, July 1996
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 16
Get Book Here
Book Description
This contract focuses on the development of sorbents and processes for removal of H2S from hot coal gas with the product of sorbent regeneration being elemental sulfur. TDA Research's process uses a regenerable tin(IV) oxide-based (SnO2) sorbent as the first sorbent and zinc ferrite (or zinc titanate) as a second sorbent.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 9
Get Book Here
Book Description
The objective of this study is to determine the feasibility of manufacturing highly reactive and attrition-resistant zinc titanate sorbents by spray drying, suitable for bubbling (conventional) as well as transport-type fluidized-bed reactor systems.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750.degree. C. to about 950.degree. C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 .mu., and about 1 part titanium dioxide having a median particle size of less than about 1 .mu. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.
