Continuous Plastic-VGO Melting Unit for Homogeneous Feed Mixing
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Solution Overview
Problem
The conversion of waste plastics into fuel and circular chemicals is challenging due to the variety of plastic types with unique thermal dynamics, mixing issues, and the presence of organic and inorganic impurities, leading to operational complications such as agglomeration and impurity accumulation.
Innovation Solution
A continuous processing unit with internal baffles, radial impellers, and overhead mixers is used to melt and dissolve waste plastics into petroleum feeds like VGO, controlling the process based on viscosity measurements and adjusting inputs to maintain optimal mixing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If waste plastics are melted and mixed with VGO, then homogeneous liquid product is achieved, but melted plastic tends to agglomerate and stick to surfaces
Solution Approach 1:
The mixing system is divided into multiple zones with different impeller types (radial flow impellers for bulk mixing, axial flow impellers for surface agitation). This segmentation allows each zone to address specific mixing challenges - radial impellers prevent agglomeration in the bulk while axial impellers prevent surface sticking and promote uniform distribution.
Solution Approach 2:
A baffle system is introduced as an intermediary element between the impellers and the tank wall. The baffles disrupt the flow patterns that cause plastic to stick to surfaces, redirecting the flow to prevent agglomeration and surface adhesion while maintaining mixing efficiency.
2Productivity
If waste plastics containing impurities are processed, then fuel and chemicals are produced, but impurities accumulate inside the mixing tank
Solution Approach 1:
A bottom discharge mechanism with specialized geometry is designed to extract accumulated impurities from the mixing tank. The discharge opening and flow patterns are configured to selectively remove heavy impurities that settle at the bottom while retaining the homogeneous plastic-VGO mixture for further processing into fuel and chemicals.
Solution Approach 2:
The system utilizes temperature control and flow rate adjustments to change the physical parameters of the mixture. By controlling viscosity and flow dynamics, impurities are kept in suspension during mixing but can be selectively removed during discharge, preventing accumulation while maintaining productivity.
3Adaptability or versatility
If multiple plastic types with unique thermal dynamics are mixed, then diverse waste plastic is processed, but mixing uniformity is compromised
Solution Approach 1:
The system employs dynamically adjustable mixing parameters including variable speed impellers and controllable residence time. Different plastic types can be processed by adjusting the rotational speed of radial and axial impellers to match their specific thermal dynamics, ensuring uniform mixing while maintaining versatility in handling diverse plastic materials.
Solution Approach 2:
The mixing system is designed with multi-functional impellers that can operate in different modes. The radial and axial flow impellers work together to handle various plastic types with different thermal properties, providing universal mixing capability while maintaining composition uniformity through coordinated operation of multiple mixing elements.
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 effectively melts and dissolves waste plastics into petroleum feeds, producing a homogeneous liquid product suitable for further treatment, reducing operational issues and enhancing the production of high-quality fuel and chemical products.
Implementation Method 1
Waste plastic is added to hot VGO in the processing unit
Implementation Method 2
The residence time for the VGO and plastic in the processing unit is sufficiently long to melt the plastic
Implementation Method 3
one or more radial impellers
Implementation Method 4
one or more overhead mixers with impellers
Data Source
AI summary
A novel process and associated equipment for effectively melting and dissolving waste plastics into petroleum feeds such as VGO are provided. The process can continuously generate a stream of blended plastic and VGO liquids that can be further treated or purified to meet fluid catalytic cracking (FCC) feedstock specifications. The entire stream can then be sent to an FCC unit to convert waste plastics into high quality gasoline fuel. The associated equipment comprises a continuous processing unit with minimum maintenance requirement.