Waste Plastic Pyrolysis Oil Chlorine Reduction

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Solution Overview

Problem

The production of waste plastic pyrolysis oil is hindered by high chlorine content and moisture, which requires costly pretreatment and refinery processes, leading to equipment corrosion and inefficient process efficiency.

Innovation Solution

A method involving pyrolysis of waste plastic feeds with 1 to 25 parts by weight of moisture at 400 to 600°C in a non-oxidizing atmosphere, without pretreatment, to minimize chlorine content and eliminate the need for drying and inert gas purge processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If waste plastic pyrolysis oil is produced using conventional refinery processes, then chlorine is removed through hydrogenation, but equipment corrosion and abnormal reactions occur due to excessive HCl generation

Engineering Contradiction:
Improvechlorine removal efficiencyVSAvoidequipment corrosion
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of moisture into a beneficial function by using water vapor generated during pyrolysis to suppress HCl generation from chlorine decomposition. The moisture that was previously considered a contaminant causing equipment corrosion is now utilized to neutralize chlorine, converting it into harmless H2O and Cl2, thereby preventing corrosion while maintaining efficient chlorine removal

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the operating parameters of the pyrolysis process by controlling the heating rate (5-20°C/min) and holding temperature (400-600°C) to optimize chlorine removal. By adjusting these parameters, the system achieves efficient chlorine decomposition while the water vapor atmosphere suppresses excessive HCl generation, resolving the contradiction between chlorine removal efficiency and equipment corrosion prevention

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If moisture-containing waste plastic is used directly in pyrolysis, then pretreatment costs are reduced, but pyrolysis oil purity decreases and impurity removal efficiency is lowered

Engineering Contradiction:
Improveprocess simplicityVSAvoidpyrolysis oil purity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of moisture into a beneficial function by utilizing water vapor generated during pyrolysis to suppress HCl generation from chlorine decomposition. The moisture that was previously considered a contaminant causing equipment corrosion is now used to neutralize chlorine, converting it into harmless H2O and Cl2, thereby preventing corrosion while maintaining efficient chlorine removal

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system uses the moisture inherently present in the waste plastic feedstock to serve the dual purpose of suppressing HCl generation and facilitating chlorine removal. The water vapor generated from the moisture-containing plastic itself creates the protective atmosphere, eliminating the need for external water addition or pretreatment processes

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If drying facilities are installed to remove moisture from waste plastic, then pyrolysis oil purity is improved, but equipment costs and utility consumption increase

Engineering Contradiction:
Improvepyrolysis oil purityVSAvoidequipment cost
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes the water vapor generated during pyrolysis of moisture-containing waste plastic to create a protective atmosphere that suppresses HCl generation. By taking out the water vapor that would otherwise be considered a contaminant and using it as a protective medium, the system eliminates the need for separate drying facilities while maintaining pyrolysis oil purity and preventing equipment corrosion

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses the moisture inherently present in the waste plastic feedstock to serve the dual purpose of suppressing HCl generation and facilitating chlorine removal. The water vapor generated from the moisture-containing plastic itself creates the protective atmosphere, eliminating the need for external water addition or pretreatment processes

Inventive Principle:
Principle #25Self-service

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 results in high-yield pyrolysis oil with reduced chlorine content, lowering equipment costs and improving economic and process efficiency by omitting pretreatment and purge processes, while effectively removing chlorine from the pyrolysis oil.

Implementation Method 1

a second step of performing pyrolysis of the feed at 400 to 600° C.

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentUS20250019596A1Method for producing waste plastic pyrolysis oil with reduced chlorine
Publication Date: 2025.01.16 SK INNOVATION CO LTD

AI summary

The present disclosure provides a method for producing waste plastic pyrolysis oil with reduced chlorine, the method including: a first step of preparing a feed containing 1 to 25 parts by weight of moisture based on 100 parts by weight of waste plastic; and a second step of performing pyrolysis of the feed at 400 to 600° C.