Plastics Depolymerization Viscosity Reduction via Crude Oil Solvent
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Solution Overview
Problem
Existing depolymerization methods face challenges in efficiently introducing heat into plastics materials, particularly with larger quantities, due to high viscosity and poor heat conductivity, limiting reactor size and economic operation.
Innovation Solution
Adding a fraction of crude oil as a solvent to the molten plastics melt reduces viscosity, improving heat introduction and allowing for larger-scale, economically viable depolymerization without catalysts, using residual oil from the crude oil processing industry, pre-heated to 150-300°C, and recirculating the plastics melt to enhance mixing and heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-temperature pyrolysis methods are used to depolymerize plastics material, then the depolymerisation temperature is high enough to break down plastics, but the energy consumption is very high and the process requires extreme temperatures of 600 to 1,000° C.
Solution Approach 1:
The patent changes the temperature parameter from high-temperature pyrolysis (600-1000°C) to low-temperature depolymerisation (300-450°C), making the process more energy-efficient while still achieving effective plastics breakdown through modified chemical reactions
Solution Approach 2:
The patent replaces thermal energy input with chemical catalysts to achieve depolymerisation, substituting the mechanical/thermal system with a chemical system that operates at lower temperatures and consumes less energy
2Use of energy by moving object
If low-temperature depolymerisation methods are used with plastics melt, then the energy consumption is reduced, but the heat introduction is difficult due to high viscosity and poor heat conductivity of plastics
Solution Approach 1:
The patent introduces a solvent as an intermediary substance that mixes with the plastics melt to reduce its viscosity and improve heat conductivity, enabling effective heat introduction at low temperatures without direct thermal contact issues
Solution Approach 2:
The patent creates a composite system by combining plastics melt with solvent to form a homogeneous mixture, where the solvent component provides improved thermal properties while the plastics component maintains the depolymerisation substrate
3Reliability
If small depolymerisation reactors with turnover volume up to 6,000 tonnes per year are created, then the heat introduction problems are manageable, but the economic operation is hardly possible due to limited capacity
Solution Approach 1:
The solvent acts as a mediator that enables scaling up reactor capacity by improving heat transfer properties of the plastics mixture, allowing large-volume reactors to maintain effective heat introduction that was previously only achievable in small reactors
4Stability of the object's composition
If the plastics melt has high viscosity, then the plastics maintain their structural integrity, but the pumpability and heat introduction into the plastics material is difficult
Solution Approach 1:
The patent changes the viscosity parameter of the plastics melt by adding solvent, reducing it to improve pumpability and heat introduction while maintaining the plastics' structural integrity through the solvent-plastics mixture
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 enables reliable and efficient thermal depolymerization of plastics materials on a larger scale, reducing energy consumption, minimizing overheating risks, and eliminating the need for stirring devices, while achieving a turnover volume of over 6,000 tonnes per year.
Implementation Method 1
adding a fraction obtained from crude oil as a solvent to the plastics melt, thereby lowering the viscosity of the plastics melt solution supplied to the depolymerisation reactor
Implementation Method 2
the plastics material is molten to form a plastics melt and degassed before being passed to a depolymerisation reactor having a heating device
Implementation Method 3
The depolymerisation of the plastics material is thus carried out by thermal cracking and not by catalytic cracking
Implementation Method 4
recirculating the plastics melt to enhance mixing and heat distribution
Data Source
AI summary
Method for the depolymerization of plastics material (1), in particular pre- or post-consumer plastics wastes, by means of heat introduction, wherein the plastics material (1) is molten to form a plastics melt and degassed before being passed to a depolymerization reactor (3), adding a fraction obtained from crude oil as a solvent (6) to the plastics melt, thereby lowering the viscosity of the plastics melt solution supplied to the depolymerization reactor (3) relative to the viscosity of the plastics melt.