Liquefied Waste Plastic Purification With pH-Controlled Heat Treatment

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Solution Overview

Problem

Existing methods for purifying liquefied waste plastics (LWP) suffer from inefficiencies in impurity removal, particularly with high acidity LWP, leading to poor purification efficiency and excessive waste water production.

Innovation Solution

A method involving heat treatment (HT) of LWP with an aqueous solution containing a basic substance, where the amount of basic substance is calculated based on the LWP's total acid number and water-oil ratio to achieve a target pH level in the aqueous phase, with pH monitoring and readjustment to maintain optimal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If common purification procedures are used for LWP, then the process is simple to operate, but purification efficiency is poor and waste water production is excessive

Engineering Contradiction:
Improvepurification efficiencyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the pH parameter of the aqueous solution to a high alkaline range (pH 12-14) and maintains it within a specific range (pH 10-12) during processing. This parameter optimization significantly improves purification efficiency for high acidity LWP while managing waste water production through controlled chemical reactions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements pH monitoring and readjustment mechanisms to maintain optimal pH levels during the purification process. This feedback control ensures consistent purification efficiency and prevents excessive waste water generation by adjusting the basic substance addition based on real-time pH measurements.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the amount of basic substance is increased to improve impurity removal, then purification efficiency improves, but waste water production increases

Engineering Contradiction:
Improveimpurity removal efficiencyVSAvoidwaste water production
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The invention optimizes the concentration of basic substance in the aqueous solution and controls the pH within a specific range (pH 10-12) rather than using excessive amounts. This parameter optimization achieves effective impurity removal while minimizing waste water production by preventing over-neutralization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses an aqueous solution that can be regenerated and reused after treatment. The washing water can be neutralized and recycled, reducing the overall production of waste water while maintaining effective impurity removal capabilities through repeated use.

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If high acidity LWP is processed without pH optimization, then the process is straightforward, but purification efficiency deteriorates

Engineering Contradiction:
Improvepurification efficiencyVSAvoidoperational simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention addresses high acidity LWP by optimizing the pH parameter of the aqueous solution to alkaline ranges (pH 12-14 initial, maintained at pH 10-12). This parameter change enables effective neutralization and purification of high acidity feeds while providing clear operational guidelines for maintaining optimal conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements pH monitoring and readjustment procedures that provide clear feedback mechanisms for operators. This ensures consistent purification efficiency for high acidity LWP while simplifying operation through standardized pH control protocols and automated monitoring where applicable.

Inventive Principle:
Principle #23Feedback

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

Enhances purification efficiency and reduces waste water production by optimizing the use of basic substances, ensuring consistent pH levels and improved impurity removal, particularly from LWP with high acidity.

Implementation Method 1

heat treatment (HT) of LWP with an aqueous solution containing a basic substance

Methodology Applied
Scientific EffectNeutralization reaction: Chemical Bonding

Implementation Method 2

heat treatment (HT) of LWP with an aqueous solution

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

followed by phase separation to result in at least a treated LWP material and an aqueous phase

Methodology Applied
Scientific EffectPhase separation: Density Gradient

Data Source

PatentUS20250346733A1Improved method for processing liquefied waste plastics
Publication Date: 2025.11.13 NESTE OYJ

AI summary

An improved method for processing liquefied waste plastics includes providing a liquefied waste plastic (LWP) feedstock for heat treatment (HT processing) with an aqueous solution containing a basic substance, subjecting the LWP feedstock to the heat treatment with the aqueous solution, followed by phase separation to result in at least a treated LWP material and an aqueous phase, determining the quality of the LWP feedstock by measuring at least one property of the LWP feedstock, the at least one property including at least the total acid number (TAN) of the LWP feedstock, and calculating an amount of the basic substance to be added in HT processing to reach a target pH level of the aqueous phase based on the at least one property of the LWP feedstock and the water-oil-ratio, and adding the calculated amount of basic.