Waste Plastic Pyrolysis with Alkaline Earth Amendment
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Solution Overview
Problem
Current methods for recycling waste plastics are inefficient in converting them into purified hydrocarbon oil products, particularly when the plastics contain halide compounds or heteroatoms from contamination sources.
Innovation Solution
A system and method that involves pre-melting waste plastic feedstock using a mixing, heating, and compacting apparatus, followed by pyrolysis in a reactor where an amendment comprising alkaline earth oxides and/or hydroxides, oxides of iron, and/or oxides of aluminum is used to remove halide compounds and heteroatoms, resulting in a hydrocarbon gas stream that is then condensed into a purified hydrocarbon oil product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If waste plastics containing halide compounds or heteroatoms are directly pyrolyzed, then the conversion process is simpler, but the resulting hydrocarbon oil product contains contaminants and is not purified
Solution Approach 1:
The patent applies preliminary action by pre-melting and densifying the waste plastic feedstock in a mixing, heating, and compacting apparatus before introducing it to the pyrolysis reactor. This preliminary processing step prepares the feedstock in a controlled manner, ensuring consistent physical properties that facilitate subsequent pyrolysis and improve the purity of the resulting hydrocarbon oil product while managing system complexity through staged processing.
Solution Approach 2:
The patent introduces an amendment comprising alkaline earth oxides and/or hydroxides, oxides of iron, and/or oxides of aluminum as an intermediary substance. This amendment interacts with halide compounds and heteroatoms during pyrolysis, facilitating their removal from the hydrocarbon gas stream. The amendment acts as a mediator that enables the separation of contaminants from the desired hydrocarbon products, thereby achieving purified oil without significantly increasing overall system complexity.
2Productivity
If waste plastics are pre-melted and processed through mixing, heating, and compacting apparatus, then the pyrolysis efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single mixing, heating, and compacting apparatus. This integrated device performs feedstock preparation, melting, amendment mixing, and densification in one unit, thereby improving pyrolysis efficiency through consistent feedstock quality while minimizing the increase in overall device complexity by combining rather than separating these functions into multiple independent apparatus.
3Manufacturing precision
If an amendment is added to remove halide compounds and heteroatoms, then the purity of hydrocarbon oil product is improved, but the loss of substance increases due to amendment consumption
Solution Approach 1:
The patent optimizes the composition and dosage parameters of the amendment to achieve effective contaminant removal while minimizing amendment consumption. By carefully adjusting the chemical composition (alkaline earth oxides/hydroxides, iron oxides, aluminum oxides) and quantity of amendment added, the system achieves high purity hydrocarbon oil products while reducing material loss through optimized stoichiometric ratios and enhanced reaction efficiency.
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 method effectively converts waste plastics into purified hydrocarbon oil products, removing contaminants like halide compounds and heteroatoms, and producing a clean, refined oil that can be readily stored, transported, and refined into fuel or other materials.
Implementation Method 1
a pyrolysis reactor configured to receive the densified melt of plastic material including the amendment, pyrolyze the densified melt of plastic material including the amendment
Implementation Method 2
heats the pre-melted feedstock such that the feedstock transitions into a vapor (e.g., one or more gases) for further processing
Implementation Method 3
one or more condensers may be provided to condense out a hydrocarbon oil product from the hydrocarbon gas stream output from the pyrolysis reactor
Implementation Method 4
The solid residue stream including a substantial portion of the halide compounds or heteroatoms of the waste plastic based feedstock via interaction of the halide compounds or heteroatoms with the amendment
Data Source
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Figure 2
AI summary
Systems and methods for processing waste plastics are provided. One method includes mixing, heating and compacting a supply of the waste plastic based feedstock having an appreciable amount of halide compounds or heteroatoms from one or more sources of contamination; providing an amendment comprising alkaline earth oxides and/or hydroxides, oxides of iron, and/or oxides of aluminum to be mixed, heated and compacted with the waste plastic based feedstock to form a densified melt of plastic material including the amendment; and pyrolyzing the densified melt of plastic material including the amendment within a pyrolysis reactor. Another method includes pyrolyzing a supply of the waste plastic feedstock within a pyrolysis reactor to generate a hydrocarbon gas stream and a solids residue stream; condensing out a tars product from the hydrocarbon gas stream output from the pyrolysis reactor with a quenching apparatus; and pyrolyzing the tars product within a supplemental pyrolysis reactor.