Propene Epoxidation Oxygen Stripping
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Solution Overview
Problem
Existing processes for recovering non-reacted propene from epoxidation reactions suffer from oxygen enrichment in the vapor phase, leading to safety concerns and efficiency losses due to the need for inert gas addition, which increases condenser size and reduces propene recovery efficiency.
Innovation Solution
A process involving the stripping of the liquid reaction mixture with an inert gas in a counter-current column to create an oxygen-depleted stream, allowing for propene recovery through absorption in a solvent without recompression or refrigeration, thereby avoiding the formation of explosive vapor mixtures and enhancing propene reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If distillation or condensation is used to recover non-reacted propene from the liquid reaction mixture, then propene recovery is achieved, but oxygen enriches in the vapor phase leading to safety concerns and requiring extra safety measures
Solution Approach 1:
The patent extracts oxygen from the liquid reaction mixture before distillation/condensation by contacting it with an inert gas in a stripping column. This removes the harmful oxygen component that would otherwise enrich in the vapor phase during subsequent separation steps, preventing explosive mixture formation while allowing efficient propene recovery.
Solution Approach 2:
The patent performs oxygen removal as a preliminary step before the main propene recovery operation. By stripping oxygen from the liquid reaction mixture beforehand, the subsequent distillation or condensation can proceed safely without oxygen enrichment issues, eliminating the need for extra safety measures during propene recovery.
2Reliability
If inert gas is added to prevent explosive vapor mixtures during condensation, then safety is improved, but condenser size increases and propene recovery efficiency decreases
Solution Approach 1:
The patent removes oxygen from the liquid reaction mixture using an inert gas stripping column before condensation. This eliminates the need to add inert gas during condensation to prevent explosive mixtures, thereby maintaining high propene recovery efficiency without compromising safety.
Solution Approach 2:
The patent performs oxygen removal as a preliminary step before condensation. By eliminating oxygen beforehand, the condensation process can operate efficiently without requiring additional inert gas addition, avoiding both safety risks and efficiency losses.
3Loss of substance
If multiple compression stages are used to compress propene vapor for absorption, then propene recovery is improved, but energy consumption and device complexity increase
Solution Approach 1:
The patent performs oxygen removal as a preliminary step before absorption. By eliminating oxygen that would interfere with absorption and reduce efficiency, the process achieves high propene recovery in a single absorption step without requiring multiple compression stages, thereby reducing device complexity and energy consumption.
Solution Approach 2:
The patent uses the stripped liquid reaction mixture (now oxygen-free) as feed for the absorption column. This feedback loop ensures that the absorption process receives optimal feed composition, achieving high propene recovery efficiency without additional compression requirements.
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 effectively recovers non-reacted propene while minimizing energy consumption and equipment size, ensuring safety by maintaining low oxygen concentrations in the strip gas stream and improving propene oxide yields without significant propene loss.
Implementation Method 1
stripping liquid reaction mixture from step a) with an inert gas in a counter-current stripping column to provide an oxygen depleted stripped liquid reaction mixture and a strip gas stream
Implementation Method 2
separating non-reacted propene from the strip gas stream obtained in step b) and recycling it to step a)
Data Source
AI summary
In a process for the epoxidation of propene, comprising continuously reacting a propene feed with hydrogen peroxide in the presence of an epoxidation catalyst in a reaction step, using propene in excess to hydrogen peroxide, to provide a liquid reaction mixture comprising non-reacted propene, extra safety measures caused by the presence of oxygen during work-up of the liquid reaction mixture of the epoxidation reaction can be avoided by stripping liquid reaction mixture from step a) with an inert gas to provide an oxygen depleted stripped liquid reaction mixture and a strip gas stream, selecting the amount of inert gas to provide an oxygen concentration in the strip gas stream in the range of from 0.1 to 10% by weight, separating non-reacted propene from the strip gas stream and recycling it to the reaction step, and separating propene oxide from the stripped liquid reaction mixture.