Alkylene Oxide Epoxidation With Catalyst Bed Switching and Heat Control
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Solution Overview
Problem
Existing epoxidation methods face challenges in controlling reaction temperature, leading to reduced selectivity and safety risks due to rapid catalyst deactivation and exothermic reactions, particularly when switching in fresh catalyst beds.
Innovation Solution
A method and system for preparing alkylene oxide that control the inlet temperature of fresh or regenerated catalyst beds using specific formulas based on temperature rises and molar ratios, ensuring the discharge temperature remains below 130°C, thereby stabilizing the reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet temperature of fresh catalyst bed is high to ensure complete conversion of organic peroxide, then the conversion rate improves, but the temperature rise exceeds control values causing side reactions and reduced selectivity
Solution Approach 1:
The reaction system is divided into multiple catalyst beds (first, second, and third beds) connected in series. The first bed uses fresh or regenerated catalyst for high conversion, while subsequent beds use deactivated catalyst to complete the reaction at lower temperatures, preventing side reactions and maintaining selectivity.
Solution Approach 2:
Different catalyst beds are assigned different catalyst states (fresh/deactivated) and operating conditions (temperature ranges) according to their specific functions. The first bed operates at higher temperature for conversion, while later beds operate at lower temperatures for selectivity, creating local optimization throughout the system.
2Manufacturing precision
If the inlet temperature is controlled low to maintain selectivity, then side reactions are reduced, but the conversion rate of organic peroxide decreases and requires larger reactor volume
Solution Approach 1:
The reaction is segmented across multiple catalyst beds with different temperature zones. High conversion occurs in the first bed at higher temperature, while complete conversion is achieved in subsequent beds at lower temperatures, combining the benefits of both high conversion rate and high selectivity.
Solution Approach 2:
The reaction proceeds continuously through multiple catalyst beds, with each bed contributing to the overall conversion. The series arrangement ensures that the organic peroxide undergoes complete conversion through cumulative action across all beds, maintaining continuous productive operation.
3Manufacturing precision
If multiple catalyst beds are used to control temperature, then selectivity is maintained, but the device complexity increases
Solution Approach 1:
The reaction system is segmented into three catalyst beds connected in series, where each bed serves a specific function in the conversion process. This segmentation enables temperature control and selectivity maintenance while distributing the conversion load across multiple units.
4Productivity
If the first catalyst bed is deactivated and replaced with fresh catalyst, then conversion rate improves, but temperature runaway risk increases due to high activity
Solution Approach 1:
The system maintains multiple catalyst beds so that when the first bed is deactivated, it can be replaced with fresh catalyst while the second and third beds continue operating. This segmentation allows catalyst replacement without shutting down the entire system and distributes the temperature control burden.
Solution Approach 2:
The system is designed with subsequent catalyst beds that act as a buffer or cushion. When fresh catalyst is introduced in the first bed, the downstream beds with deactivated catalyst provide a safety margin that prevents temperature runaway, as they can absorb excess heat and continue the reaction at controlled temperatures.
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 the conversion rate and selectivity of alkylene oxide production while preventing temperature runaway and reducing energy consumption.
Implementation Method 1
epoxidation reaction zone provided with at least two catalyst beds connected in series... to carry out an epoxidation reaction
Implementation Method 2
epoxidation reaction is a highly exothermic reaction
Data Source
Figure 1~3
Figure 4~5
AI summary
The present invention discloses a method and system for preparing alkylene oxide. The method comprises feeding a feed comprising an olefin, an alkylbenzene hydroperoxide and an alkylbenzene into a reaction zone comprising at least two catalyst beds connected in series to carry out an epoxidation reaction to obtain a reaction product comprising an alkylene oxide, wherein when the logically first stage catalyst bed is deactivated, it is switched out and a fresh catalyst bed or a regenerated catalyst bed is switched in; wherein the inlet temperature of the feed entering the switched-in fresh catalyst bed or regenerated catalyst bed satisfies the following formula (1) such that the temperature of the discharge leaving the switched-in fresh catalyst bed or regenerated catalyst bed is lower than or equal to 130 °C: 40°C≤TNinlet≤130°C+∑i=1N−1Tioutlet−Tiinlet−1370a1+1.38b1 The system is used for preparing alkylene oxide, and the system comprises a temperature controller, which controls the inlet temperature of the feed to the newly switched-in fresh catalyst bed or regenerated catalyst bed such that the inlet temperature satisfies the formula (1).