Catalysts gradually lose their catalytic activity, usually through structural changes, poisoning, overheating or the deposition of extraneous material such as coke. A catalyst is “spent” when it no longer exhibits the necessary activity or specificity required by the user. Depending primarily upon the chemical and structural changes in the catalyst during use, the user may have a number of options for dealing with the spent catalyst, which include:
- Regeneration and reuse of the material
- Use of the material in another process
- Recovery of some or all of the components in the material
- Disposal of the material
Spent fluid catalytic cracking (FCC) catalysts
Fluid catalytic cracking (FCC) catalysts are principally composed of silica/alumina zeolite. In most cases, these cannot be re-used in reused in catalyst applications but may be recovered for use in other applications. Attention needs to be given to the appropriate handling and waste legislation.