A NOVEL MEMBRANE REACTOR FOR DIRECT HYDROGEN PRODUCTION FROM COAL

Doong, Shain ; Ong, Estela ; Atroshenko, Mike ; Lau, Francis ; Roberts, Mike

Gas Technology Institute

关键词: Coal Gasification;    Hydrogen Production;    Flowsheets;    Membranes;    08 Hydrogen;   

DOI  :  10.2172/842713
RP-ID  :  NONE
RP-ID  :  FC26-03NT41851
RP-ID  :  842713

美国|英语

来源: UNT Digital Library

【 摘 要 】

Gas Technology Institute is developing a novel concept of membrane reactor coupled with a gasifier for high efficiency, clean and low cost production of hydrogen from coal. The concept incorporates a hydrogen-selective membrane within a gasification reactor for direct extraction of hydrogen from coal-derived synthesis gases. The objective of this project is to determine the technical and economic feasibility of this concept by screening, testing and identifying potential candidate membranes under high temperature, high pressure, and harsh environments of the coal gasification conditions. The best performing membranes will be selected for preliminary reactor design and cost estimates. Hydrogen permeation data for several perovskite membranes BCN (BaCe{sub 0.9}Nd{sub 0.1}O{sub 3-x}), SCE (SrCe{sub 0.9}Eu{sub 0.1}O{sub 3}) and SCTm (SrCe{sub 0.95}Tm{sub 0.05}O{sub 3}) have been successfully obtained for temperatures between 800 and 950 C and pressures from 1 to 12 bar in this project. However, it is known that the cerate-based perovskite materials can react with CO{sub 2}. Therefore, the stability issue of the proton conducting perovskite materials under CO{sub 2} or H{sub 2}S environments was examined. Tests were conducted in the Thermo Gravimetric Analyzer (TGA) unit for powder and disk forms of BCN and SCE. Perovskite materials doped with zirconium (Zr) are known to be resistant to CO{sub 2}. The results from the evaluation of the chemical stability for the Zr doped perovskite membranes are presented. During this reporting period, flowsheet simulation was also performed to calculate material and energy balance based on several hydrogen production processes from coal using high temperature membrane reactor (1000 C), low temperature membrane reactor (250 C), or conventional technologies. The results show that the coal to hydrogen process employing both the high temperature and the low temperature membrane reactors can increase the hydrogen production efficiency (cold gas efficiency) by more than 50% compared to the conventional process. Using either high temperature or low temperature membrane reactor process also results in an increase of the cold gas efficiencies as well as the thermal efficiencies of the overall process.