Fluidized Bed Epichlorohydrin Oxidation for Full Peroxide Conversion
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Solution Overview
Problem
Existing epichlorohydrin production methods, such as the propylene high-temperature chlorination, propylene acetate, and glycerine methods, suffer from low yield, high wastewater generation, and environmental pollution, while direct oxidation using a continuous stirred-tank reactor faces incomplete hydrogen peroxide conversion, safety risks, and rapid catalyst deactivation.
Innovation Solution
A process utilizing a liquid-solid circulating fluidized bed reactor for directly oxidizing chloropropene with hydrogen peroxide, involving a reactor system with specific components and catalyst regeneration, achieving complete hydrogen peroxide conversion and efficient epichlorohydrin production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous stirred-tank reactor is used for direct oxidation of chloropropene with hydrogen peroxide, then the reaction can proceed continuously, but hydrogen peroxide conversion is incomplete and safety risks increase
Solution Approach 1:
The continuous stirred-tank reactor is segmented into multiple CSTRs connected in series. This segmentation allows the reaction to proceed through multiple stages, with each reactor contributing to incremental conversion of hydrogen peroxide. The multi-stage configuration ensures complete conversion while maintaining continuous operation, thereby resolving the contradiction between productivity and reliability.
2Productivity
If a continuous stirred-tank reactor is used for direct oxidation, then continuous operation is achieved, but residence time is relatively long leading to rapid catalyst deactivation
Solution Approach 1:
By dividing the reactor into multiple CSTRs in series, the overall residence time is distributed across multiple stages. Each stage operates at optimized conditions that minimize catalyst exposure to deactivating factors while maintaining continuous flow. This segmentation reduces the cumulative damage to the catalyst compared to a single long-residence-time reactor, thereby extending catalyst lifetime while preserving continuous operation.
3Productivity
If a continuous stirred-tank reactor is used for direct oxidation, then continuous production is enabled, but side reactions increase and epichlorohydrin selectivity decreases
Solution Approach 1:
The multi-CSTR configuration allows each reactor stage to be optimized for specific reaction conditions. By controlling residence time, temperature, and reagent addition in each stage, the main oxidation reaction is promoted while side reactions are suppressed. This staged approach enables continuous production while maintaining high epichlorohydrin selectivity, resolving the contradiction between productivity and manufacturing precision.
4Ease of manufacture
If propylene high-temperature chlorination method is used, then epichlorohydrin can be produced through a established process, but chlorine atom utilization rate is low and environmental pollution is severe
Solution Approach 1:
The process transitions from high-temperature chlorination to oxidation under milder conditions. By changing the reaction parameters (from chlorination to oxidation, from high temperature to moderate temperature), the process achieves high chlorine atom utilization rate (84%) and minimal wastewater generation (5% of conventional methods), while maintaining ease of manufacture through the standardized multi-CSTR configuration.
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
The process achieves a hydrogen peroxide conversion rate of 99.9%, an effective utilization rate of 96.0%, and epichlorohydrin selectivity of 99.0%, significantly improving reaction efficiency and reducing reaction time compared to continuous stirred-tank reactors.
Implementation Method 1
directly oxidizing chloropropene with hydrogen peroxide to produce epichlorohydrin
Implementation Method 2
liquid-solid circulating fluidized bed reactor
Data Source
AI summary
A process for preparing epichlorohydrin is by directly oxidizing chloropropene with hydrogen peroxide using a liquid-solid circulating fluidized bed reactor. The liquid-solid circulating fluidized bed reactor has a reactor, a liquid-solid separator, a liquid extractor, a spent material inclined tube, a regenerator, a catalyst bin, a regeneration inclined tube, etc. In the process, the liquid-solid circulating fluidized bed reactor is used to replace a traditional stirred tank reactor, such that the heat and mass transfer rate between liquid and solid phases is enhanced in the reactor, the back mixing degree in the reactor is reduced, the reaction rate is greatly increased, the reaction time is shortened, side reactions are inhibited, and the effective utilization rate of hydrogen peroxide and the selectivity of epichlorohydrin are increased.