Equilibrium catalyst usually refers to the

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

mix use in

fluid catalytic cracking Fluid catalytic cracking (FCC) is the conversion process used in petroleum refineries to convert the high-boiling point, high-molecular weight hydrocarbon fractions of petroleum (crude oils) into gasoline, alkene gases, and other petroleum produc ...

(FCC), but includes other petrochemical processes that use large amounts (many tons) of catalysts. The catalyst is a

zeolite Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a meta ...

. During the FCC, the catalyst "inventory" is regularly removed from operation and reactivated by combusting the accumulated coke, which is a catalyst poison. Some of the catalyst is irreversibly deactivated by metal contaminants and by degradation of the alumino silicate backbone of the zeolite. To compensate for these changes, some inventory is removed and some fresh catalyst is added. Thus, the inventory consists of a catalytic particles with a range of activities. This mixture is referred to as the equilibrium catalyst. In addition to FCC, equilibrium catalyst concept applies to

hydroprocessing Hydroprocessing is a catalytic term relating to the processes of hydrocracking and hydrotreating. These process are for the removal of sulfur, oxygen, nitrogen and metals from crude oil, this is done in the refining of fuel A fuel is any ma ...

and

hydrocracking In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking ...

Spent catalyst disposal

The disposal of spent catalyst is gaining importance, particularly because of strict environmental regulations and high prices of fresh catalyst.

Landfill A landfill is a site for the disposal of waste materials. It is the oldest and most common form of waste disposal, although the systematic burial of waste with daily, intermediate and final covers only began in the 1940s. In the past, waste was ...

s and approved dumping sites have been predominantly used to get rid of the spent catalyst. Catalysts containing metals (

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

vanadium Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

molybdenum Molybdenum is a chemical element; it has Symbol (chemistry), symbol Mo (from Neo-Latin ''molybdaenum'') and atomic number 42. The name derived from Ancient Greek ', meaning lead, since its ores were confused with lead ores. Molybdenum minerals hav ...

) classified as hazardous are pre-treated before disposal.Cerqueira, H. S.; Caeiro, G.; Costa, L.; Ramoa Ribeiro, F. Journal of Molecular Catalysis A: Chemical 2008, 292, 1-13 Sale of spent catalyst to the cement industry or its reuse in construction sites,

metal casting In metalworking and jewelry making, casting is a process in which a liquid metal is delivered into a mold (usually by a crucible) that contains a negative impression (i.e., a three-dimensional negative image) of the intended shape. The metal is ...

industry, in road building offers immediate disposal solutions but with no economic benefits. Depending upon the quality of the spent catalyst, a specific property/attribute of the ECAT might be desirable in other processes. With some modifications in spent catalyst compositions, it could be reused in less severe processes.

References

{{reflist Oil refining Chemical processes