Polymerisation Reactor Wall Thickness Optimization

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Solution Overview

Problem

The efficiency of heat removal in loop reactors is limited by the thickness of the reactor wall, which is constrained by the need to withstand internal and external pressures, leading to suboptimal production rates and potential for reactor failure due to hydrostatic pressure.

Innovation Solution

Reducing the design pressure of the cooling jacket while maintaining the reactor wall's ability to withstand internal pressures, allowing for a thinner reactor wall without changing the construction material, and optimizing the reactor wall thickness based on ASME Boiler and Pressure Vessel code calculations to minimize thermal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the reactor wall thickness is reduced to improve heat transfer efficiency, then the heat transfer coefficient increases and cooling efficiency improves, but the reactor wall may fail to withstand the hydrostatic pressure of the cooling fluid

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidresistance to hydrostatic pressure
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent changes the design pressure parameter of the cooling jacket from a conventional high value to a reduced value (Pj < 0.0018 × Pr² + 2.25), which allows the reactor wall to be thinner while still maintaining sufficient strength to withstand the reduced hydrostatic pressure of the cooling fluid, thereby improving heat transfer efficiency without compromising structural integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies prior cushioning by designing the cooling jacket with a reduced pressure system that inherently limits the hydrostatic pressure before it can cause damage. The design pressure formula creates a built-in safety margin that prevents the wall from experiencing excessive pressure loads, allowing for thinner walls while maintaining safety

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the reactor wall thickness is reduced to enhance heat transfer, then the thermal resistance decreases and cooling efficiency improves, but the risk of plastic deformation and elastic buckling increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidplastic deformation and elastic buckling risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By changing the design pressure parameter to a reduced value, the patent enables thinner wall construction that improves thermal conductivity and heat transfer efficiency while the reduced pressure environment prevents plastic deformation and elastic buckling that would occur with conventional thicker walls under high pressure

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the design pressure of the cooling jacket is reduced to allow thinner wall construction, then heat transfer efficiency improves and material costs decrease, but the cooling system must operate at lower pressures which may affect cooling capacity

Engineering Contradiction:
Improveproduction rateVSAvoidcooling system operating pressure
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent optimizes the design pressure parameter to a specific reduced range that balances heat transfer efficiency with adequate cooling capacity. The formula Pj < 0.0018 × Pr² + 2.25 determines the optimal pressure level that enables thinner walls for improved heat transfer while maintaining sufficient pressure for effective cooling operation

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2242569B1Polymerisation reactor with heat exchange jacket
Publication Date: 2016.10.05 INEOS MANUFACTURING BELGIUM NV

AI summary

A tubular reactor for use in polymerisation reactions is described, having a design pressure PR of 40-65 barg, at least a portion of which is oriented vertically and at least part of which vertical portion is surrounded by a concentric jacket for the passage of cooling fluid, wherein the design pressure in barg of the jacket PJ is less than 0.0018.PR 225. Another aspect of the invention concerns a tubular reactor for use in polymerisation reactions having a design pressure PR of 40-65 barg, at least a portion of which is oriented vertically and at least part of which vertical portion is surrounded by a concentric jacket for the passage of cooling fluid, wherein the actual thickness of the reactor wall is either no more than 2mm greater and/or no more than 10% greater than the minimum wall thickness required to withstand the design pressure PR as calculated according to the ASME Boiler and Pressure Vessel code.