High Pressure Reactor Fouling Reduction via Segmented Temperature Control

Solution Overview

Problem

High pressure polymerization reactors face issues with fouling due to polymer deposition on internal walls, leading to reduced cooling efficiency, reactor contamination, and potential 'decomp' reactions, which are not effectively addressed by current methods.

Innovation Solution

A method to determine the liquid-liquid equilibrium boundary and critical polymer concentration using equation of state models like Sanchez-Lacombe or PC-SAFT, allowing for the generation of phase diagrams to optimize operating conditions and maintain polymer dissolution in the liquid phase, thereby preventing fouling and improving heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high temperature difference between reactants and cooling medium is used to achieve highest conversion, then productivity is improved, but polymer precipitation and fouling on internal walls increases

Engineering Contradiction:

ImproveconversionVSAvoidfouling

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the temperature parameter profile along the reactor length, using higher temperature differences in the first region for conversion and lower temperature differences in the second region to prevent polymer precipitation and fouling, thus resolving the contradiction between productivity and fouling

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The reactor is segmented into at least two regions with different temperature profiles: a first region with higher temperature difference for maximum conversion and a second region with lower temperature difference to maintain polymer dissolution and prevent fouling, allowing simultaneous optimization of both objectives

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If cooling capacity is increased to prevent polymer deposition, then fouling is reduced, but heat transfer efficiency decreases due to impaired cooling

Engineering Contradiction:

Improvepolymer depositionVSAvoidcooling efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The invention dynamically adjusts the temperature profile along the reactor length, using higher temperature differences in the first region for conversion and lower temperature differences in the second region to maintain polymer dissolution and prevent fouling, thus resolving the contradiction between productivity and fouling

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the temperature parameter profile along the reactor length, using higher temperature differences in the first region for conversion and lower temperature differences in the second region to prevent polymer precipitation and fouling, thus resolving the contradiction between productivity and fouling

Inventive Principle:

Principle #35Parameter changes

3Productivity

If reactor operating time is extended to improve productivity, then productivity is improved, but polymer deposits accumulate and require cleaning

Engineering Contradiction:

Improveoperational timeVSAvoidpolymer deposits

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The reactor is segmented into at least two regions with different temperature profiles: a first region with higher temperature difference for maximum conversion and a second region with lower temperature difference to maintain polymer dissolution and prevent fouling, allowing simultaneous optimization of both objectives

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention maintains continuous polymer dissolution throughout the reactor by ensuring the temperature profile in the second region keeps the polymer in dissolved state, enabling extended operational time without accumulation of deposits that would require cleaning

Inventive Principle:

Principle #20Continuity of useful action

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 extends reactor run time between cleanings, maintains product quality, and prevents decomposition by ensuring polymer remains dissolved, enhancing heat transfer and operational safety.

Implementation Method 1

modeling experimental or literature data for the liquid liquid equilibrium using an equation of state model

Methodology Applied

Scientific EffectLiquid-liquid equilibrium: Phase Change

Implementation Method 2

heat transfer from the reaction to the cooling jacket is impaired

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

deposition of polymer on the internal reactor wall

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS9663591B2Reduction of fouling in high pressure reactors

Publication Date: 2017.05.30 NOVA CHEM (INT) SA

AI summary

The Application of equations of state to experimental and literature data permits the formation of a model and phase diagram(s) that show under what conditions polyethylene is likely to precipitate out of a high pressure solution of polyethylene in supercritical ethylene. This then permits a better definition to run a high pressure reactor to reduce the likelihood of phase separation, loss of cooling and potentially decomposition of the reactor contents.