Catalyst for steam reforming of hydrocarbons

Abstract

An improved catalyst is described which comprises a normally cylindrical refractory support having gas passages communicating from end to end and oriented parallel to its axis and having gas passages in the shape of segments of circles (pie-shaped), square, hexagonal, circular, oval or sinusoidal. The exterior and interior surfaces are coated with catalytic compositions. The length of the refractory support is significantly less than the diameter. Further, there is a definite ratio of height to effective internal diameter (H:ID) of each of the gas passages. These catalysts are especially effective for endothermal reactions because both the internal and external surfaces of the support are coated with catalysts and are more efficiently heated. This is especially true for the internal surfaces of the support (i.e., the walls of the axially oriented gas passages) which heretofore have been shielded from the infra-red rays radiating from the tubes of the catalytic reactor. Thus, heat transfer to the catalyst surface is more effective in maintaining the interior surface at the desired elevated reaction temperature. The structures are especially effective for the steam-hydrocarbon reforming reaction, particularly when the hydrocarbon is in the boiling range of naphtha or below.

We claim: 
     
       1. A .[.hydrocarbon reforming.]. catalyst, comprising a .[.cylindrical.]. .Iadd.cylindrical .Iaddend.refractory support .[.selected from the group consisting of aluminum oxide, magnesium oxide, calcium oxide and metal aluminate spinels, and.]. having two or more gas passages extending axially therethrough from one end to the other and a catalytically-active metal comprising nickel or cobalt oxide deposited thereon .[.in a concentration of 6% to 30% by weight, expressed as the metal oxide.]., said catalyst having a Relative Activity Coefficient Factor (ACF.[.®.]..Iadd. R  .Iaddend.) and a Relative Pressure Factor (PF.[.®.]..Iadd. R  .Iaddend.) being in excess of that when compared to a standard ring, said ACF.[.®.]..Iadd. R  .Iaddend.being in excess of .[.1.]. .Iadd.1.15 .Iaddend.and the ratio of ACF.[.®.]..Iadd. R  .Iaddend.to said PF.[.®.]..Iadd..sup. R .Iaddend.being in excess of .[.1:1.]. .Iadd.1.25:1, .Iaddend.the Height (H) of said support bearing a relationship to the effective internal diameter of each of said gas passages (ID), the ratio of H:ID being less than 4:1. 
     
     
       2. A .[.hydrocarbon reforming.]. catalyst, as defined in claim 1, in which said .[.cylindrical.]. .Iadd.cylindrical .Iaddend.refractory support is in the form of a spoked wheel, having a peripheral rim, a centrally-located hub and a plurality of radially-extending spokes, defining pie-shaped gas passages. 
     
     
       3. A .[.hydrocarbon reforming.]. catalyst, as defined in claim 1, in which said support has a surface area in the range of from 0.5 to 55 m 2  /gm. .Iadd.4. A catalyst, as defined in claim 1, in which said catalytically-active metal is nickel oxide..Iaddend. .Iadd.5. A catalyst, as defined in claim 1, in which said catalytically-active metal is cobalt oxide..Iaddend. .Iadd.6. A catalyst, as defined in claim 1, in which said catalytically-active metal is present in a concentration of from 6% to 30% by weight, expressed as the metal oxide..Iaddend. .Iadd.7. The catalyst, as defined in claim 1, in which said refractory support consists essentially of aluminum oxide..Iaddend.