Dividing-Wall Distillation for Propylene Oxide–Styrene Co-Production
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Solution Overview
Problem
Existing processes for co-producing propylene oxide and styrene monomer face challenges in increasing capacity and efficiency, necessitating improvements that can be implemented in existing facilities using commonly used equipment and techniques.
Innovation Solution
The use of a dividing-wall column (DWC) replaces a cascade of two conventional distillation columns, facilitating the co-production process by introducing multiple feed streams and enabling the separation of high-purity products, thereby reducing capital and operating costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cascade of two conventional distillation columns is used to process recycle streams, then the separation performance is achieved, but the capital cost and operating cost are higher
Solution Approach 1:
The patent combines two separate distillation columns into a single dividing-wall column (DWC) that performs the same separation function. The DWC integrates the functionality of two columns by using a vertical partition wall to divide the column into two sections, allowing simultaneous separation of multiple components (ethylbenzene and methylbenzyl alcohol) in one unit, thereby reducing capital cost while maintaining separation performance
Solution Approach 2:
The dividing-wall column uses a vertical partition wall to segment the single column into two functional sections (feed side and product side), each handling different separation tasks. This segmentation allows the DWC to achieve the separation performance of two conventional columns while operating as a single integrated unit, reducing overall device complexity and cost
2Manufacturing precision
If a cascade of two conventional distillation columns is used to process recycle streams, then the separation performance is achieved, but the operating cost is higher
Solution Approach 1:
The patent merges two distillation columns into one dividing-wall column, which reduces the total number of reboilers and condensers needed. This integration decreases energy consumption by eliminating redundant heating and cooling equipment, thereby reducing operating costs while maintaining the same separation performance through the partitioned column design
3Productivity
If existing facilities are retrofitted to increase capacity and efficiency, then production capability is improved, but the complexity of implementation increases
Solution Approach 1:
The dividing-wall column is designed to perform multiple separation functions within a single unit, making it a universal equipment that can handle different recycle streams and separation requirements. This multi-functionality allows existing facilities to increase capacity and efficiency through retrofitting with a single versatile DWC rather than adding multiple specialized columns, reducing retrofit complexity
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 DWC provides equivalent performance to conventional systems while lowering capital and operating costs, making it suitable for new or retrofitted facilities, and enhancing the efficiency of propylene oxide and styrene monomer production.
Implementation Method 1
Distillation conditions are implemented in the DWC to facilitate withdrawal of an overhead product stream, an intermediate product stream, and a bottoms product stream
Data Source
AI summary
Disclosed is the use of a dividing-wall column in a process for co-producing propylene oxide and styrene monomer. Feed streams to a dividing-wall column comprise a bottoms product produced in recovering crude propylene oxide from an epoxidation reaction product, a hydrogenated byproduct styrene monomer production, and a light fraction of a bottoms product withdrawn from the dividing-wall column. Products from the dividing-wall column comprise an overhead product comprising ethylbenzene for recycle to an oxidation zone, an intermediate product comprising methylbenzyl alcohol and acetophenone as feed to a dehydration zone to produce styrene monomer, and a bottoms product comprising methylbenzyl alcohol and heavy materials.