Olefin Production via Circulating Fluidized Bed Regeneration
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Solution Overview
Problem
The circulating fluidized bed process for olefin production faces challenges with low olefin selectivity and high energy consumption due to catalyst deactivation and coke generation, leading to decreased hydrocarbon conversion rates and increased energy costs.
Innovation Solution
The method involves operating the circulating fluidized bed process in the Fast Fluidization Regime with an alumina-type catalyst, maintaining specific temperature and pressure conditions, and optimizing catalyst circulation and regeneration to enhance olefin selectivity and productivity, thereby reducing energy consumption and investment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the circulating fluidized bed process is used to achieve short contact time between hydrocarbon and catalyst, then the hydrocarbon conversion rate increases, but the olefin selectivity becomes very low due to rapid byproduct generation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the fluidization velocity to maintain a specific catalyst volume fraction range (0.02-0.2) in the riser. This parameter optimization ensures that the contact time between hydrocarbon and catalyst is sufficient for high conversion while preventing excessive byproduct formation, thereby achieving both high olefin selectivity and conversion rate simultaneously
2Productivity
If the fixed bed dehydrogenation process is used, then the olefin yield is very good at initial stage, but the hydrocarbon conversion rate and olefin yield decrease and energy consumption increases due to catalyst deactivation and excessive coke generation as time goes
Solution Approach 1:
The patent implements dynamics by transitioning from a static fixed bed system to a dynamic circulating fluidized bed system where catalyst continuously circulates between the riser and regenerator. This dynamic operation allows fresh catalyst to be continuously supplied to maintain high activity and deactivated catalyst to be regenerated, eliminating the gradual performance degradation inherent in fixed bed processes
Solution Approach 2:
The patent applies discarding and recovering by separating the catalyst circulation into two streams: active catalyst is continuously supplied to the riser for dehydrogenation while deactivated catalyst containing coke is continuously withdrawn and sent to the regenerator for coke removal. This separation and recovery process maintains catalyst stability and prevents excessive coke accumulation
3Speed
If the circulating fluidized bed process operates with high catalyst circulation, then the contact time is reduced, but the energy consumption for regeneration process increases
Solution Approach 1:
The patent optimizes the regeneration energy consumption by controlling the catalyst circulation rate and adjusting the regenerator operating parameters accordingly. By maintaining the catalyst volume fraction in the optimal range, the system achieves efficient dehydrogenation with moderate circulation rates, avoiding excessive energy consumption in the regenerator while still preventing catalyst deactivation
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 olefin selectivity and economic efficiency by reducing fuel consumption by 10-15% and compressor energy by 15-20%, lowering investment costs through reduced air flow and equipment requirements.
Implementation Method 1
dehydrogenating it in the presence of an alumina type catalyst
Implementation Method 2
Providing the regenerated catalyst and the hydrocarbon including not less than 90 wt % of LPG into a Riser of Fast Fluidization Regime
Data Source
AI summary
Disclosed is an olefin production method which includes: (a) providing the regenerated catalyst and the hydrocarbon including not less than 90 wt % of LPG into Riser of Fast Fluidization Regime, and dehydrogenating in the presence of an alumina type catalyst; (b) separating an effluent from the dehydrogenation reaction into the catalyst and propylene mixture; (c) stripping to remove the hydrocarbon compound included in the catalyst separated at stage (b); (d) mixing the catalyst stripped at stage (c) with the gas including oxygen, and continuously regenerating it; (e) recycling the catalyst regenerated at stage (d) to stage (a), and providing it again into Riser; and (f) producing propylene product by cooling, compressing and separating propylene mixture of the reaction product separated at stage (b).