CERAMIC MEMBRANES FOR HYDROGEN PRODUCTION FROM COAL

Gavalas, George R.

California Institute of Technology (United States)

关键词: Coal;    Water Vapor;    Membranes;    08 Hydrogen;    01 Coal, Lignite, And Peat;   

DOI  :  10.2172/812539
RP-ID  :  NONE
RP-ID  :  FG26-00NT40817
RP-ID  :  812539

美国|英语

来源: UNT Digital Library

【 摘 要 】

The objective of this project is to develop ceramic membranes for hydrogen separation from fuel gas or synthesis gas at temperatures 400-500 C. The membrane chosen for this purpose consists of a dense silica layer coated on a porous support by chemical vapor depositrion (CVD). The support used during the reporting period was zeolite silicalite grown on macroporous alumina tubes. Chemical vapor deposition was carried out using alternating exposure of the support to silicon tetrachloride (SiCl{sub 4}) and water vapor at 400-500 C. Under these conditions it takes about twenty-five reaction cycles to narrow down the pores of the zeolite support sufficiently for separation of hydrogen from other gases. The membranes were characterized by gas adsorption for pore size distribution, scanning electron microscopy, and EDAX for elemental composition. The permeance of H{sub 2}, N{sub 2}, CO{sub 2}, n-C{sub 4}H{sub 10}, and i-C{sub 4}H{sub 10} was measured in the temperature range 100-250 C. At 150 C, the H{sub 2}:N{sub 2} permeance ratio was in the range 100-200 at a hydrogen permeance of 5-10x10{sup -8} mol/m{sub 2}-s-Pa.