Patent ID: 7560090

Claim:
A process for producing hydrogen using a permselective membrane reactor comprising the steps of: providing a permselective membrane reactor that includes a reactor tube that has a gas inlet at one end and a gas outlet at the other end, a separator tube disposed in the reactor tube, a permselective membrane selectively permeable to hydrogen on a surface thereof, a discharge outlet for passing separated gas through the permselective membrane, and a layer comprising a reforming catalyst that promotes reforming of ethanol, wherein β defined by the following equation is in a range of 0.05 to 20: β=a/b, wherein a denotes the volume of the reforming catalyst layer [cm 3 ] in the permselective membrane reactor, and b denotes the area of the permselective membrane [cm 2 ] in the permselective membrane reactor; supplying a raw material gas containing ethanol from the gas inlet of the reactor tube; producing a gas mixture containing hydrogen, carbon monoxide, and carbon dioxide by a catalytic reaction; recovering hydrogen from the discharge outlet of the separator tube, hydrogen passing through the permselective membrane into the separator tube and thereby being separated from the gas mixture; and discharging other gas components that do not pass through the permselective membrane from the gas outlet of the reactor tube; wherein the hydrogen is produced under conditions where a hydrogen recovery rate defined by the following equation is in a range of 60% to 99%: Hydrogen recovery rate=100×{ A /( A+B )} wherein A denotes the amount of hydrogen that passes through the permselective membrane (the amount of permeated hydrogen) [ml/min], and B denotes the amount of hydrogen that does not pass through the permselective membrane (the amount of non-permeated hydrogen) [ml/min], and wherein α defined by the following equation is at least 0.6: α={(CO 2 )/(CO) 2 }/K wherein (CO 2 ) denotes the partial pressure of carbon dioxide at the gas outlet of the reactor tube, (CO) denotes the partial pressure of carbon monoxide at the gas outlet of the reactor tube, and K denotes the equilibrium constant of the disproportionation reaction of carbon monoxide at the internal temperature of the reactor tube.