Waste Plastic Pyrolysis with Hot Filter and Recycle Loop
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Solution Overview
Problem
The challenge lies in producing refined hydrocarbons from waste plastics while addressing the high content of impurities, particularly chlorine, which leads to equipment corrosion and abnormal reactions during the hydrodesulfurization process, and achieving a high yield of light hydrocarbons and solid coke.
Innovation Solution
A method involving pretreatment of waste plastics, pyrolysis in a reactor, lightening process using a hot filter filled with beads, and coking, where the condensed liquid is re-introduced into the reactor, with a temperature gradient formed by external heaters, to produce high-value-added pyrolysis oil with a high proportion of light hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pyrolysis oil is used as fuel without pretreatment, then energy production is achieved, but air pollutants (SOx, NOx, HCl) are emitted causing environmental harm and equipment corrosion
Solution Approach 1:
The patent applies preliminary action by implementing a pretreatment process before the pyrolysis oil is used as fuel. The pretreatment unit removes impurities including sulfur, nitrogen, and chlorine components from the pyrolysis oil, preventing subsequent pollution and corrosion issues while maintaining energy production capabilities
2Manufacturing precision
If pyrolysis oil with high chlorine content is introduced to hydrodesulfurization process, then sulfur removal is achieved, but equipment corrosion and abnormal reactions occur due to excessive HCl production
Solution Approach 1:
The patent applies preliminary action by removing chlorine components during the pretreatment stage before the pyrolysis oil enters the hydrodesulfurization process. This preliminary chlorine removal prevents excessive HCl production during hydrodesulfurization, thereby avoiding equipment corrosion and abnormal reactions while maintaining effective sulfur removal
Solution Approach 2:
The patent applies the extraction principle by specifically targeting and removing harmful impurities (sulfur, nitrogen, chlorine) from the pyrolysis oil through the pretreatment unit. This selective extraction of harmful components allows the subsequent hydrodesulfurization process to operate reliably without the complications caused by high chlorine content
3Productivity
If waste plastics are directly pyrolyzed without pretreatment, then pyrolysis oil is produced quickly, but the oil contains large amounts of impurities requiring complex post-treatment
Solution Approach 1:
The patent applies preliminary action by performing impurity removal during the pretreatment stage before pyrolysis. This approach maintains high productivity by avoiding complex post-treatment processes while ensuring the pyrolysis oil has sufficiently low impurity content for direct use as fuel or chemical feedstock
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 method effectively reduces impurities, improves pyrolysis oil yield, and produces refined hydrocarbons with a high proportion of light hydrocarbons and solid coke, enhancing process efficiency and economic feasibility.
Implementation Method 1
producing pyrolysis gas by introducing the waste plastics pretreated in the pretreatment process into a pyrolysis reactor
Implementation Method 2
producing in a lightening process pyrolysis oil by introducing the pyrolysis gas into a hot filter
Implementation Method 3
A temperature gradient may be formed in the hot filter. The temperature gradient may be formed by providing at least two heaters outside the hot filter
Data Source
AI summary
A method and associated system for producing refined hydrocarbons from waste plastics. The method and system provide for: pretreating waste plastics; producing pyrolysis gas by introducing the waste plastics pretreated in the pretreatment process into a pyrolysis reactor; producing in a lightening process pyrolysis oil by introducing the pyrolysis gas into a hot filter; and a coking process of coking the pyrolysis oil, wherein a liquid condensed in the hot filter is re-introduced into the pyrolysis reactor. The system produces refined hydrocarbons from the waste plastics.