Catalyst carrier is a special part of solid catalyst, which is the dispersant, binder and supporter of active components of catalyst, and sometimes plays a role of Co catalyst or catalyst assistant. Catalyst carrier, also known as the support, is one of the components of the supported catalyst. Generally, porous material has a certain specific surface area. The active components of the catalyst are often attached to it. The carrier is used to support the active component first, so that the catalyst has specific physical properties, and the carrier does not have catalytic activity. The content of catalyst component is large. In view of its effect, the related personnel of Naite Aluminum and trade combined with their years of work experience, have introduced the effect of catalyst carrier as follows, and quickly learn more about it!
Requirements for catalyst carrier
1. Can dilute the density of active components, especially precious metals
2. Can be prepared into a certain shape
3. It can prevent sintering between active components to a certain extent
4. Can resist poison
5. It can have mutual effect with active components and effect with main catalyst.
The effect of catalyst carrier
1. Reduce catalyst cost
2. Improve mechanical strength of catalyst
3. Improve the thermal stability of catalyst
4. Activity and selectivity of catalyst addition
5. Extend catalyst life
Introduction of several primary carriers
1. Active alumina: the most used carrier for industrial catalyst. It is cheap, high in heat resistance and good in affinity of active components.
2. Silica gel: the chemical composition is SiO2. It is generally produced by acidizing water glass (Na2SiO3). Silicate is formed after the effect of water glass and acid; silicic acid polymerizes and contracts to form polymer with uncertain structure.
SiO2 is a carrier used more, but it is less than Al2O3 in industry. This is due to the difficulties in preparation, weak affinity with active components, easy sintering under the coexistence of water vapor.
3. Diatomite: natural SiO2. The pore structure and specific surface of metal oxides and organic matter vary with the origin. Acid treatment is required before use. One is to improve SiO2 content, increase specific surface, specific pore volume and primary hole radius; second, to improve thermal stability, after acid treatment, the specific surface can be further increased. Diatomite is used to prepare fixed bed catalyst.
4. Activated carbon: the primary ingredient is C, containing a small number of H, O, N, s and ash. The activated carbon has irregular grinding structure, and the surface has carbonyl, quinone, hydroxyl and carboxyl groups. Activated carbon has developed pores and large surface area, and is stable and stable.
5. TiO2: it has anatase, titanite and rutile. Anatase is difficult to synthesize due to instability; anatase is formed at a lower temperature with a relative density of 3.84 and a larger specific surface area; anatase becomes rutile when heated at 600-1000 ° C. the relative density of rutile is 4.22, and the specific surface area is small.
6. Silicon carbide: the melting point of carbide ceramics is higher than 2000 ° C, which has high heat conductivity, high hardness, strong heat resistance and impact resistance, but it is simply oxidized in oxygen atmosphere. Therefore, SiC is often used as the carrier of high temperature environmental catalyst.
7. Molecular sieve: a crystalline silicate or aluminate, a channel and cavity system composed of a silica tetrahedron or an aluminum oxygen tetrahedron connected by an oxygen bridge bond. It has high thermal stability, hydrothermal stability and acid and alkali resistance