Integrated Circulating Fluidized Bed for Light Olefin Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in oil and petroleum refining is to maximize the yield of light olefins in fluidized catalytic cracking units, which is hindered by high regenerator temperatures due to coke deposition, leading to reduced catalyst circulation and conversion of hydrocarbon feedstock into light olefins, and existing methods either deactivate catalysts or require additional heat sinks like catalyst coolers.
Innovation Solution
An integrated circulating fluidized bed process that routes coke-laden catalyst from the hydrocarbon cracking reactor to an ethanol dehydration reactor, where the endothermic dehydration process reduces catalyst temperature, allowing for lower regenerator temperatures and increased catalyst activity, thereby enhancing hydrocarbon conversion and light olefin yields without the need for additional cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a higher reaction temperature is used in the regenerator to burn off coke, then coke removal is improved, but the regenerator temperature increases excessively leading to reduced catalyst circulation and lower light olefin yield
Solution Approach 1:
An intermediary heat exchanger is introduced between the regenerator and the cracking reactor to cool the regenerated catalyst before it enters the cracking zone. This mediator allows the regenerator to operate at high temperature for effective coke combustion while preventing the excessive temperature from reaching the catalyst in the cracking reactor, thus maintaining high catalyst circulation and light olefin yield
Solution Approach 2:
The catalyst circulation system is segmented into distinct temperature zones: a high-temperature regenerator for coke combustion, a cooling section with heat exchanger to reduce catalyst temperature, and a lower-temperature cracking reactor for optimal light olefin production. This segmentation allows each zone to operate at its optimal temperature independently
2Productivity
If a catalyst cooler is used to reduce regenerator temperature, then light olefin yield is improved, but the device complexity increases
Solution Approach 1:
The heat exchanger serves multiple functions simultaneously: it cools the regenerated catalyst to prevent excessive temperature in the cracking reactor, preheats the incoming hydrocarbon feedstock to reduce energy consumption, and recovers heat from the hot catalyst for overall process efficiency. This multi-functionality achieves light olefin yield improvement without proportionally increasing device complexity
Solution Approach 2:
The cooling function is merged with the feed preheating function in a single heat exchanger unit. The hot regenerated catalyst serves as the heating medium for the incoming feed while being cooled itself, combining two thermal management functions into one integrated device rather than requiring separate cooling and preheating systems
3Productivity
If the catalyst to oil ratio is increased to improve light olefin conversion, then conversion is improved, but the regenerator temperature increases due to higher coke deposition
Solution Approach 1:
The system is segmented into independent temperature control zones that allow the cracking reactor to operate with high catalyst to oil ratio for maximum conversion while the regenerator handles the thermal load of coke combustion separately, and the heat exchanger manages the temperature transition between these zones
Solution Approach 2:
The heat exchanger acts as an intermediary that decouples the thermal relationship between the regenerator and cracking reactor, allowing the cracking reactor to maintain high catalyst circulation ratios for improved conversion without directly experiencing the high temperatures generated during coke combustion in the regenerator
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 increases the catalyst-to-oil ratio, reduces coke levels on catalysts, maintains catalyst activity, and maximizes light olefin yields by utilizing excess heat for ethanol dehydration, ensuring higher conversion and flexibility in processing hydrocarbon feedstocks with varying Conradson carbon content.
Implementation Method 1
the endothermic dehydration of ethanol with residue hydrocarbon processing, which results in the utilization of excess heat
Implementation Method 2
burning the coke on the deactivated catalyst in the presence of air or oxygen containing gases at a temperature in a range of 600-700° C.
Implementation Method 3
burning the coke on the deactivated catalyst in the presence of air or oxygen containing gases
Implementation Method 4
cracking of a hydrocarbon feedstock in presence of a regenerated catalyst obtained from a coke combustor
Data Source
AI summary
The present disclosure provides a process for high conversion residue cracking in a circulating fluidized bed reactor while integrating it with the dehydration of ethanol. More particularly, the present disclosure relates to an integrated circulating fluidized bed process for the simultaneous dehydration of ethanol and cracking of a hydrocarbon feedstock. By integrating the cracking reactor with ethanol dehydration reactor, more conradson carbon residue feedstock can be processed in cracking reactor while limiting the coke combustor temperature.