Pressurized Hot Solvent Circulation for Reactor Polymer Cleaning

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Solution Overview

Problem

Existing methods for cleaning oligomerization reactors are inefficient, leading to prolonged shutdowns, increased costs, and reduced production due to polymer accumulation, which is not effectively addressed by conventional solvent circulation methods.

Innovation Solution

A reactor cleaning method involving pressurizing a washing solvent container to 5 kg/cm² to 40 kg/cm² with a pressurized gas, supplying the solvent to the reactor's lower and side portions, and maintaining a temperature of 115°C to 200°C during solvent circulation to enhance washing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional solvent circulation methods are used to clean the reactor, then the reactor can be washed, but the washing rate is slow and shutdown time is prolonged

Engineering Contradiction:
Improvewashing rateVSAvoidshutdown time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The washing solvent is pre-heated to 115°C to 200°C before being supplied to the reactor. This preliminary heating action ensures that the solvent reaches optimal washing temperature quickly upon contact with the polymer accumulation, significantly accelerating the washing rate and reducing the time required to stop the reactor for cleaning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A pressurized gas is introduced into the washing solvent container to increase the solvent's supply pressure. This pneumatic action enables the hot solvent to be rapidly supplied to the lower and side portions of the reactor, improving circulation efficiency and washing rate while minimizing shutdown time.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If the reactor is stopped for washing, then polymer accumulation is removed, but production is reduced and costs increase

Engineering Contradiction:
Improvereactor cleanlinessVSAvoidproduction
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The washing solvent is pre-heated to optimal temperature before use, ensuring that when the reactor is stopped for washing, the cleaning process occurs rapidly at peak efficiency. This minimizes the duration of production interruption while ensuring thorough removal of polymer accumulation, thus maintaining reactor cleanliness without excessive production loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Pressurized gas is used to enhance solvent circulation speed and penetration into polymer accumulation areas. This pneumatic assistance ensures that the washing process is completed as quickly and thoroughly as possible during the necessary shutdown period, maximizing reactor cleanliness while minimizing production downtime and associated costs.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If solvent is supplied only to the upper reactor, then the circulation system is simple, but washing efficiency is insufficient for polymer accumulation

Engineering Contradiction:
Improvewashing efficiencyVSAvoidsolvent supply system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The solvent supply system is segmented into multiple supply points: the upper reactor and the lower reactor. This segmentation allows the pressurized hot solvent to simultaneously reach different accumulation zones of polymer within the reactor, significantly improving washing efficiency without requiring overly complex distribution mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Pressurized gas is used to drive the solvent circulation system, enabling efficient multi-point supply to both upper and lower reactor portions. The pneumatic pressure ensures adequate solvent flow to all critical areas, achieving high washing efficiency while maintaining a relatively simple overall system architecture through centralized pressurization.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 method significantly improves the washing rate of polymer accumulation in reactors, reducing shutdown time, lowering costs, and enhancing production stability by optimizing solvent circulation conditions.

Implementation Method 1

pressurizing a washing solvent container to 5 kg/cm2 to 40 kg/cm2 with a pressurized gas

Methodology Applied
Scientific EffectPressurisation: Pressurisation

Implementation Method 2

maintaining a temperature of 115°C to 200°C during solvent circulation

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4197658B1Reactor cleaning method
Publication Date: 2026.04.01 LG CHEM LTD
  • EP4197658B1 patent drawingFigure 1
  • EP4197658B1 patent drawingFigure 2
  • EP4197658B1 patent drawingFigure 3

AI summary

The present invention relates to a reactor cleaning method. The method includes pressurizing a washing solvent container to 5 kg/cm2.g to 40 kg/cm2.g using pressurized gas; supplying a washing solvent stream from the washing solvent container to one or more of a lower portion and a side portion of the reactor to fill an inside of the reactor; and circulating the washing solvent stream between the washing solvent container and the reactor while maintaining a temperature of the reactor at 115°C to 200°C.