Propene Recovery Scrubbing Solvent Water Mixture
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Solution Overview
Problem
Current processes for separating propene from propane in the production of propylene oxide are energy-intensive and require multiple distillation stages, making them economically inefficient.
Innovation Solution
A process using a suitable entraining agent in a scrubber to separate propene and propane, allowing for the recovery of propene and recycling it back into the process, while eliminating propane, thereby reducing the need for multiple distillation stages and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low temperature and/or high-pressure distillation is used to separate propene from propane, then separation is achieved, but energy consumption increases significantly
Solution Approach 1:
An entraining agent (water or water-miscible organic solvent) is introduced as an intermediary substance to facilitate the separation of propene from propane. The entraining agent selectively interacts with propene through absorption or solvation, enabling separation at milder conditions without requiring extreme temperatures or pressures, thus reducing energy consumption while maintaining separation purity
Solution Approach 2:
The invention changes the separation mechanism from purely thermal distillation to a combined approach using absorption/solvation parameters. By adjusting parameters such as solvent type, temperature, and pressure within moderate ranges, the process achieves effective propene-propane separation without the excessive energy demands of conventional low-temperature/high-pressure distillation
2Manufacturing precision
If multiple distillation stages are used to separate propene from propane, then separation efficiency improves, but device complexity and capital costs increase
Solution Approach 1:
The entraining agent acts as a mediator that enhances the relative volatility between propene and propane in a single or reduced number of distillation stages. By selectively absorbing propene, the entraining agent creates a more favorable separation scenario that reduces the need for multiple complex distillation columns while maintaining high separation efficiency
Solution Approach 2:
The invention extracts propene from the propene-propane mixture using an entraining agent in an extraction column before the distillation step. This pre-extraction removes a portion of the separation burden, allowing the subsequent distillation stage to operate more efficiently with fewer stages required to achieve the desired separation purity
3Quantity of substance
If conventional distillation is used to separate propene, then propene recovery is achieved, but propylene oxide loss increases due to entrainment
Solution Approach 1:
The entraining agent serves as a selective intermediary that preferentially interacts with propene over propylene oxide. Through selective absorption or solvation, it captures propene while leaving propylene oxide in the distillate phase, thereby achieving propene recovery without significant loss of the valuable propylene oxide product
Solution Approach 2:
The process creates local quality differences by using an entraining agent with specific affinity for propene. This selective interaction occurs in the extraction zone where the entraining agent is introduced, creating a localized environment that favors propene uptake while minimizing propylene oxide involvement, thus reducing product loss
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 enables efficient and simple separation of propene and propane, reducing energy consumption and the number of required stages, making the process more economically advantageous.
Implementation Method 1
separating propane from the stream S1 in a separation zone, comprising subjecting the stream S1 to washing conditions in a scrubber, wherein a solvent mixture comprising organic solvent and water is added as entraining agent
Implementation Method 2
separating propene and propane from the effluent stream by distillation, comprising subjecting the effluent stream to distillation conditions in a distillation unit
Data Source
AI summary
The invention relates to a process for preparing propylene oxide, comprising (i) providing a stream comprising propene, propane, hydrogen peroxide or a source of hydrogen peroxide, water, and an organic solvent; (ii) passing the liquid feed stream provided in (i) into an epoxidation zone comprising an epoxidation catalyst comprising a titanium zeolite, and subjecting the liquid feed stream to epoxidation reaction conditions in the epoxidation zone, obtaining a reaction mixture comprising propene, propane, propylene oxide, water, and the organic solvent; (iii) removing an effluent stream from the epoxidation zone, the effluent stream comprising propene, propane, propylene oxide, water, and the organic solvent; (iv) separating propene and propane from the effluent stream by distillation, comprising subjecting the effluent stream to distillation conditions in a distillation unit, obtaining a gaseous stream (S1) which is enriched in propene and propane compared to the effluent stream subjected to distillation conditions, and a liquid bottoms stream (S2) which is enriched in propylene oxide, water and organic solvent compared to the effluent stream subjected to distillation conditions; (v) separating propane from the stream (S1) in a separation zone, comprising subjecting the stream (S1) to washing conditions in a scrubber, wherein a solvent mixture comprising organic solvent and water is added as entraining agent, obtaining a bottoms stream (S3), which comprises organic solvent, water and at least 70 weight-% of the propene comprised in (S1); and a gaseous top stream (S4), which comprises at least 5 weight-% of the propane comprised in stream (S1).