Dual Fluid Catalytic Cracking Zones for Balanced Regenerator Heat
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Solution Overview
Problem
The production of light olefins such as ethylene and propylene is challenging due to insufficient heat from coke in fluid catalytic cracking processes, requiring supplemental fuels or expensive catalyst cooling systems, and existing processes are limited by the availability and processing requirements of hydrocarbon feeds.
Innovation Solution
A method involving two reaction zones with different hydrocarbon feeds and a common regenerator, using whole crude oil and gas condensate feeds to balance coke production and heat load without supplemental fuels or catalyst coolers, employing a common regenerator to regenerate spent catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heavy hydrocarbon feeds are used in FCC processes, then coke production increases providing sufficient heat, but the feed supply is limited and processing complexity increases
Solution Approach 1:
The FCC process is divided into two separate reaction zones, each receiving different hydrocarbon feeds (heavy and light). This segmentation allows each zone to be optimized for its specific feed type while both contribute to the common regenerator, resolving the contradiction between heat provision and feedstock availability.
Solution Approach 2:
Two different feed streams (heavy and light hydrocarbons) are merged into a single common regenerator system. This combining approach allows the system to utilize diverse feedstocks while achieving balanced coke production and heat supply, eliminating the need for supplemental fuels or catalyst coolers.
2Adaptability or versatility
If light hydrocarbon feeds are used in FCC processes, then feedstock availability increases, but coke production is insufficient requiring supplemental fuels
Solution Approach 1:
The FCC process is divided into two separate reaction zones, each receiving different hydrocarbon feeds (heavy and light). This segmentation allows each zone to be optimized for its specific feed type while both contribute to the common regenerator, resolving the contradiction between heat provision and feedstock availability.
Solution Approach 2:
Two different feed streams (heavy and light hydrocarbons) are merged into a single common regenerator system. This combining approach allows the system to utilize diverse feedstocks while achieving balanced coke production and heat supply, eliminating the need for supplemental fuels or catalyst coolers.
3Reliability
If coke is combusted in the regenerator, then catalyst is regenerated and heated, but excessive coke requires expensive catalyst cooling systems
Solution Approach 1:
The system changes the operational parameters by introducing two different feed types with distinct coke production characteristics. This parameter change balances the total coke load in the regenerator, preventing overheating and eliminating the need for catalyst cooling systems while maintaining reliable catalyst regeneration.
Solution Approach 2:
The system converts the potentially harmful effect of excessive coke (which would require cooling systems) into a beneficial balance by using light hydrocarbon feeds that produce less coke. This balanced approach eliminates the need for catalyst coolers while maintaining effective catalyst regeneration.
4Use of energy by moving object
If supplemental fuels are used in the regenerator, then heat supply is sufficient, but operating costs increase
Solution Approach 1:
The system achieves self-service by using the coke produced from the hydrocarbon feeds themselves to provide the necessary heat in the regenerator. By balancing the coke production from heavy and light feeds, the system eliminates the need for external supplemental fuels, reducing operating costs while maintaining sufficient heat supply.
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
Achieves balanced coke production and heat supply, eliminating the need for supplemental fuels and catalyst coolers, while utilizing widely available and minimally processed hydrocarbon feeds to enhance the production of light olefins.
Implementation Method 1
a feedstock is reacted in the presence of a catalyst, which forms coke on the surface of the catalyst
Implementation Method 2
The coked catalyst is passed to a regenerator where the coke is combusted to regenerate and heat the catalyst
Implementation Method 3
The hot, regenerated catalyst is then passed back to the reactor where it provides heat for endothermic cracking reactions
Data Source
AI summary
Embodiments are directed to a method for operating a fluidized catalytic cracker comprising: reacting a heavy hydrocarbon feed and a first catalyst to produce a first cracked effluent and a first spent catalyst with coke deposited thereon; reacting a light hydrocarbon feed and a second catalyst to produce a second cracked effluent and a second spent catalyst with coke deposited thereon; regenerating the first spent catalyst and the second spent catalyst in a common regenerator, by combusting coke deposited on the first spent catalyst and the second spent catalyst, thereby forming fresh catalyst, which is passed back to the first reaction zone as the first catalyst and to the second reaction zone as the second catalyst, wherein: the first reaction zone and the second reaction zone are each fluidized catalytic cracking zones operated at high severity conditions; and the common regenerator is operated without supplemental fuel or catalyst coolers.