Hydrocarbon Mixture from Plastic Waste via Multi-Stage Pyrolysis
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Solution Overview
Problem
Existing processes for converting plastic waste into hydrocarbon compound mixtures often result in products with high boiling points and significant wax fractions, leading to inefficient pyrolysis and pollution issues during storage and transport.
Innovation Solution
A process involving the conversion of plastic waste into hydrocarbon compound mixtures using a multi-compartment pyrolysis apparatus, where the vapor temperature in the first compartment is set between 400°C and 500°C, and in the second compartment between 350°C and 450°C, with controlled backflow and condensation to achieve a cloud point of ≤15°C and a final boiling point of ≤430°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional single-stage pyrolysis is used to convert plastic waste, then the process is simple, but the product has high boiling point and significant wax fractions causing pollution
Solution Approach 1:
The pyrolysis process is divided into multiple stages with different temperature zones. The first stage operates at higher temperature (400-500°C) to crack long-chain hydrocarbons, while the second stage operates at lower temperature (350-450°C) to condense and separate products. This segmentation allows progressive breakdown of plastic waste into smaller molecules, reducing wax fractions and improving product quality.
2Manufacturing precision
If higher pyrolysis temperature is applied to reduce wax content, then the cloud point improves, but energy consumption increases
Solution Approach 1:
The process uses periodic temperature variation across different stages. The first compartment maintains higher temperature for cracking, while the second compartment uses lower temperature for condensation. This periodic temperature action across stages achieves effective wax reduction and cloud point control while distributing energy consumption efficiently across the process stages.
3Manufacturing precision
If multi-compartment pyrolysis apparatus is used to improve product quality, then cloud point and boiling point improve, but device complexity increases
Solution Approach 1:
The apparatus combines pyrolysis and condensation functions into an integrated multi-compartment system. The first compartment performs high-temperature pyrolysis while the second compartment performs condensation at lower temperature. By merging these functions in sequence within a single apparatus, the system achieves improved product quality without requiring separate independent units for each function.
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
The process produces hydrocarbon compound mixtures with improved properties, such as low cloud point and transparent layers, reducing pollution and enabling efficient use as alternative feedstock in oil refineries and steam crackers.
Implementation Method 1
converting plastic waste materials into liquid hydrocarbon compound mixtures by pyrolysis
Implementation Method 2
the vapor within the first of such compartments having a higher temperature than the vapor within the second compartment
Data Source
Figure 1
AI summary
The invention relates to a hydrocarbon compound mixture having a cloud point of ≤15°C and being transparent in layers of 40 mm in thickness at 20°C in accordance with the relevant standard test method for measuring the cloud point, obtained by a process of converting plastic waste materials into liquid hydrocarbon compound mixtures. The invention further relates to a process for the conversion of plastic waste materials into such liquid hydrocarbon compound mixtures, and to the use of that hydrocarbon compound mixture as feedstock for a refinery crude unit or a steam cracker.