Dual Riser FCC Process with Segregated Separation for Propylene Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Fluid Catalytic Cracking (FCC) processes face challenges in maximizing propylene yield without significantly increasing capital and utility costs, as reducing reactor pressure or recycling light naphtha to a conventional reactor riser either incurs high costs or offers limited economic benefits.
Innovation Solution
A dual riser-dual separation section flow scheme is employed, where the effluent from the second riser reactor is directed to a segregated separation section, allowing for increased propylene yield with reduced capital and utility costs compared to dual riser systems with common separation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dual reactor system is used to maximize propylene yield, then propylene production is improved, but capital costs increase
Solution Approach 1:
The patent combines the product recovery systems of two reactors into a single integrated system. The first and second reactors share common separation equipment including distillation columns and heat exchangers. This merging approach maintains the productivity benefits of dual reactors while reducing capital costs by eliminating redundant equipment.
Solution Approach 2:
The common separation system serves multiple functions: it processes effluent from both reactors, performs product separation for both streams, and provides heat exchange services to both reactor systems. This multi-functionality reduces the overall equipment inventory and capital investment while maintaining high propylene yield.
2Productivity
If light naphtha is recycled to a conventional reactor riser to increase propylene yield, then propylene production is improved, but utility costs increase
Solution Approach 1:
The patent implements continuous recycling of light naphtha from the product recovery system back to the reactor system. This continuous recycle stream maintains high propylene production rates by continuously converting light naphtha to propylene, while the integrated heat exchange network recovers energy to minimize utility costs.
Solution Approach 2:
The patent optimizes operating parameters including temperature, pressure, and recycle ratios to maximize propylene yield while minimizing energy consumption. The product recovery system operates at optimized conditions to facilitate efficient light naphtha recycle with reduced utility requirements.
3Productivity
If reactor pressure is reduced to maximize propylene yield, then propylene production is improved, but capital costs increase
Solution Approach 1:
The patent utilizes reduced reactor pressure as an operating parameter to maximize propylene yield. The integrated product recovery system is designed to handle the effluent at these optimized pressure conditions, eliminating the need for additional pressure management equipment and minimizing capital costs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances propylene yield economically by minimizing capital and utility costs, achieving higher propylene production with less dilution of the hydrocarbon feed and reduced recirculation of C4+ material, thereby improving process economics.
Implementation Method 1
The wash column is in downstream communication with the second reactor and in upstream communication with the first reactor. The wash column may include a pump-arounds to increase the heat recovery but no reboiler.
Implementation Method 2
In another process embodiment, the subject invention involves vaporizing a portion of the first cracked products to provide the second hydrocarbon feed.
Implementation Method 3
Fluid catalytic cracking (FCC) is a catalytic hydrocarbon conversion process accomplished by contacting heavier hydrocarbons in a fluidized reaction zone with a catalytic particulate material.
Implementation Method 4
Fluid catalytic cracking (FCC) is a catalytic hydrocarbon conversion process accomplished by contacting heavier hydrocarbons in a fluidized reaction zone with a catalytic particulate material.
Implementation Method 5
A high temperature regeneration with oxygen within a regeneration zone operation burns coke from the spent catalyst which may have been stripped.
Data Source
AI summary
A process is disclosed for catalytically converting two feed streams. The feed to a first catalytic reactor may be contacted with product from a second catalytic reactor to effect heat exchange between the two streams and to transfer catalyst from the product stream to the feed stream. The feed to the second catalytic reactor may be a portion of the product from the first catalytic reactor.