The Platforming processes, focusing on the semi-regenerative and continuous configurations:
Platforming Process:
A catalytic reforming process used in refineries to convert low-octane naphtha into high-octane reformate, a key gasoline blending component.
The process involves dehydrogenation and isomerization reactions that rearrange the carbon skeletons of the naphtha molecules, producing branched-chain isomers with higher octane numbers.
Semi-regenerative Platforming:
This was the original platforming configuration developed in 1949.
Key features:
Fixed-bed reactors: The process utilizes a series of 2-3 fixed-bed reactors containing a platinum-based catalyst.
Batch regeneration:
Reactors operate continuously for 6-24 months.
The entire unit needs to be shut down periodically for catalyst regeneration.
Regeneration involves burning off coke deposits accumulated on the catalyst during operation.
Limitations:
Requires downtime for regeneration, leading to lower on-stream factors.
Less flexible in adapting to fluctuating market demands.
Continuous Platforming:
Developed later to address the limitations of the semi-regenerative process.
Key features:
Moving-bed reactors:
Utilizes a continuous moving-bed reactor system.
Spent catalyst is continuously removed from the bottom of the reactor and sent to a separate regeneration zone.
Regenerated catalyst is reintroduced at the top of the reactor.
Continuous operation:
Enables continuous reforming without requiring complete unit shutdowns.
Offers greater flexibility in responding to changing feedstock or product requirements.
Higher operating costs:
Requires complex moving-bed reactor systems and additional equipment for catalyst handling and regeneration.
Comparison:
Feature- Semi-regenerative Platforming
Reactor- configuration Fixed-bed
Catalyst -regeneration Batch, requires unit shutdown
On-stream factor- Lower (downtime for regeneration)
Flexibility- Less flexible
Operating costs -Lower
Feature -Continuous Platforming
Reactor configuration- Moving-bed
Catalyst regeneration- Continuous
On-stream factor -Higher (continuous operation)
Flexibility – More flexible
Operating costs Higher
Additional points:
While continuous platforming offers advantages in terms of on-stream time and flexibility, it is also a more complex and expensive process to operate compared to the semi-regenerative version.
The choice between these configurations depends on factors like refinery size, desired production capacity, and economic considerations.
Other platforming variations exist, such as cyclic reforming, which uses a swing reactor to extend on-stream times between regenerations.