Polyether Polyol Production Heat Removal via Parallel Cooling
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Solution Overview
Problem
Continuous processes for producing polyether polyols using double metal cyanide (DMC) catalysts are limited by the rate of heat removal in reactors, leading to capacity constraints without affecting product quality.
Innovation Solution
Implementing a system with a continuous reactor and water-cooled heat exchangers to efficiently remove heat generated during the exothermic oxyalkylation reaction, utilizing recirculation and parallel heat exchangers to manage heat effectively and increase space-time yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous processes for producing polyether polyols using DMC catalysts are used, then product quality is maintained with low unsaturation and low polydispersity, but plant capacity is limited by heat removal rate
Solution Approach 1:
The cooling system is segmented into multiple parallel heat exchangers rather than using a single heat exchanger. This segmentation allows the total cooling capacity to be distributed across multiple units, enabling higher overall heat removal rates while maintaining effective cooling of the reaction mixture.
Solution Approach 2:
Multiple heat exchangers are merged into a parallel configuration where cooling water flows through multiple heat exchangers simultaneously. This merging of cooling pathways increases the total heat transfer surface area and capacity, allowing the system to handle higher reaction rates and improve plant capacity.
2Productivity
If heat removal rate is increased to improve plant capacity, then productivity increases, but system complexity increases
Solution Approach 1:
The parallel heat exchanger system serves multiple functions simultaneously: it provides enhanced cooling capacity for high-rate reactions, offers redundancy for reliable operation, and allows flexible adjustment of cooling capacity by controlling flow distribution. This multi-functionality justifies the increased system complexity.
Solution Approach 2:
The continuous parallel cooling system maintains constant effective cooling throughout the reaction process, ensuring that heat removal keeps pace with heat generation at high reaction rates. This continuous effective action enables sustained high productivity without temperature excursions.
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 plant capacity by effectively utilizing the energy from the exothermic reaction, increasing space-time yields by up to 30% while maintaining product quality and reducing energy usage for steam generation.
Implementation Method 1
continuously removing heat from the polyether polyol by utilizing a water-cooled heat exchanger
Implementation Method 2
water-cooled heat exchanger comprises: (1) a cooling water inlet in fluid communication with a source of cooling water; and (2) a cooling water outlet in fluid communication with a boiler system
Implementation Method 3
The foregoing oxyalkylation in the presence of a DMC catalyst is an exothermic reaction
Data Source
Figure 1
AI summary
Disclosed are processes and systems for producing polyether polyols and for the recovery of heat generated during such polyether polyol production.