Regeneration of reforming catalyst

In order to recycle the expensive reforming catalyst, it is necessary to restore the activity and selectivity of the deactivated catalyst, which is called catalyst regeneration. For the semi-regenerative catalytic reforming unit, regeneration can only be carried out after the unit is shut down. When the catalyst should be regenerated is usually determined by the following factors: ① The operating reactor temperature has been raised to the limit temperature; ② Liquid yield drops to the limit of economic yield. In addition, regeneration should also be carried out if the catalyst is severely deactivated by sulfur contamination or if the water chlorine balance is severely disturbed. Catalyst regeneration is carried out in the following three steps:

1）Burn charcoal. The carbon deposits on the catalyst were burned at an appropriate oxygen concentration (0.3%~0.8%). It is necessary to increase the burning speed to shorten the burning time and not to make the temperature too high to ensure that the catalyst structure is not damaged.

2）Fill with chlorine. The chlorine lost in the combustion of coke should be supplied to the catalyst, the platinum fused during the reaction and combustion should be dispersed. Usually, dichloroethane and trichloroethane are added to fully oxidize the metals at high temperature to form compounds that can move freely. The purpose is to disperse the gathered active metals evenly again, and to supplement the lost chlorine components, so as to improve the performance of the catalyst.

3）Reduction. The chlorinated oxidation state catalyst was reduced to metal state catalyst and metal crystallization and dispersion was achieved. The reducing agent is hydrogen. In addition, if the catalyst is contaminated with sulfur, it must be desulfurized by a hydrogen system before burning the charcoal.