Title of Invention

A PROCESS FOR THE PREPARATION OF HYDROGEN RICH GAS

Abstract

(57) Abstract: The invention relates to a process for the preparation of hydrogen rich gas from a feed stock. It consists of the dimethyl ether and steam, in which the dimethyl ether is reacted with steam in presence of an ether hydration catalyst selected from the group of solid acids preferably from zeolitic material, alumina silicate, silica alumina, alumina and mixtures thereof and a methanol decomposition catalyst of Cu-Zn-alumina in a weight ratio of between 1:5 and 5:1 is arranged in physical admixture in a fixed bed reactor. PRICE: THIRTY RUPEES

Full Text

) The present invention relates to a process for the preparation of hydrogen rich gas. More particular, the invention is a process for the preparation of such gas from a feed stock consisting of dimethyl ether (DME). Decomposition of DME to hydrogen proceeds by a two step reaction. In a first reaction the ether is hydrated to methanol by the reaction: (1) and methanol produced during hydration of DME is in a second step decomposed to carbon oxides and hydrogen; (2) (3) Both reactions may take place in gas and liquid phase. Reaction (1) proceeds in the presence of weak acids at a very low reaction rate and the reaction is thermodynamically unfavorable to methanol. Methanol decomposition by the above reactions (2) and (3) is known to be catalyzed by a solid catalyst, usually based on copper, zinc and aluminum oxides. Thermodynamically it is favoured by high temperature, low pressure and high steam concentration. It has now been found that the reaction rate during hydration of DME to methanol by reaction (1) is much improved when carrying out the reaction in presence of a solid acid. It has furthermore been observed that the overall reaction of DME to hydrogen rich gas by the following reaction : (4) proceeds at reasonable reaction rates and at high product yield and selectivity for the formation of hydrogen and carbon oxides, when overcoming the equilibrium limitations of DME hydration reaction (1) by removing produced methanol as it forms through the reaction of methanol to hydrogen and carbon oxides according to the above reactions (2) and (3). Accordingly the present invention provides a process for the preparation of hydrogen rich gas from a feed stock consisting of the dimethyl ether and steam, wherein the dimethyl ether is reacted with steam in presence of an ether hydration catalyst selected from the group of solid acids preferably from zeolitic material, alumina silicate, silica alumina, alumina and mixtures thereof and a methanol decomposition catalyst of Cu-Zn-alumina in a weight ratio of between 1:5 and 5:1 being arranged in physical admixture in a fixed bed reactor. A suitable catalyst for the hydration of dimethyl ether is any of the solid acids. Preferably, the hydration catalyst comprises acidic zeolites, most preferably ZSM-5 in its H-form. The DME hydration catalyst is physically admixed with the methanol decomposition catalyst of, preferably, Cu-Zn-alumina in a weight ratio of between 1:5 and 5:1 as supplied from Haldor Topsoe A/S. Prior to contact with the feed gas, the catalysts are brought in their active form, which for the hydration catalyst is the hydrogen form obtained by ion exchange of the catalyst with a proton donating solution. The methanol ent temperatures as specified below in Table 1. WE CLAIM : 1. A process for the preparation of hydrogen rich gas from a feed stock consisting of the dimethyl ether and steam, wherein the dimethyl ether is reacted with steam in presence of an ether hydration catalyst selected from the group of solid acids preferably from zeolitic material, alumina silicate, silica alumina, alumina and mixtures thereof and a methanol decomposition catalyst of Cu-Zn-alumina in a weight ratio of between 1:5 and 5:1 being arranged in physical admixture in a fixed bed reactor. 2. The process as claimed in claim 1, wherein the dimethyl ether hydration catalyst comprises ZSM-5 in its hydrogen form and/or aluminosilicates material with the Boehmite structure. 3. The process as claimed in claim 1, wherein the reaction is carried out at a temperature between 200-400°C and a pressure from 2-50 bar. 4. A process for the preparation of hydrogen rich gas, substantially as hereinabove described and exemplified.

Documents:

1196-mas-1996 abstract.pdf

1196-mas-1996 claims.pdf

1196-mas-1996 correspondence others.pdf

1196-mas-1996 correspondence po.pdf

1196-mas-1996 description (complete).pdf

1196-mas-1996 form-2.pdf

1196-mas-1996 form-26.pdf

1196-mas-1996 form-4.pdf

1196-mas-1996 form-6.pdf

1196-mas-1996 others.pdf

1196-mas-1996 petition.pdf