Industrial catalysts

Industrial catalysts can be broadly grouped into three categories

1. Bulk catalysts: When the entire catalyst consists of the catalytically active substance then the solid catalyst is called a bulk catalyst.  Examples include silica- alumina catalysts for catalytic cracking; Iron- molybdate for oxidation of methanol to formaldehyde; iron doped with alumina and potassium oxide for the synthesis of ammonia.

2. Supported catalysts: In supported catalysts, the catalytically active materials are dispersed over the high surface area support material. For example hydrodesulphurization is carried over molybdenum oxide supported on alumina.

3. Mixed agglomerates: These catalysts are agglomerated mixture of active substance and support. These type of catalysts are used less frequently.

 

Fig. 1. Basic unit operations in solid catalyst preparation