Pyrolysis Plastic Oil Purification for Steam Cracker Feed
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Solution Overview
Problem
Pyrolysis plastic oil contains high levels of dienes that react to form gums and act as coke precursors, preventing its direct use in steam crackers, necessitating a purification process to remove these components.
Innovation Solution
A process involving cationic polymerization with acidic catalysts to convert dienes into oligomeric products, followed by neutralization, washing, and separation to produce a purified stream suitable for steam cracking, yielding ethylene and propylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If pyrolysis plastic oil is used as a raw material for producing ethylene and propylene, then production cost is reduced and waste plastic is utilized, but the oil contains sulfur and nitrogen compounds that poison catalysts and reduce reaction efficiency
Solution Approach 1:
The patent extracts and removes harmful sulfur and nitrogen compounds from pyrolysis plastic oil through a dedicated purification unit before the oil enters the oligomerization reactor. This extraction process eliminates catalyst poisons while retaining the valuable hydrocarbon components for ethylene and propylene production.
Solution Approach 2:
The patent introduces a purification unit as an intermediary between the pyrolysis unit and the oligomerization unit. This intermediary component treats the pyrolysis plastic oil by removing harmful impurities, allowing the harmful substances to be separated out while the cleaned oil proceeds to productive conversion.
2Productivity
If conventional oligomerization processes are used, then ethylene and propylene can be produced, but the process requires high investment and operating costs due to complex purification requirements
Solution Approach 1:
The patent changes the operational parameters of the oligomerization reactor, specifically operating at temperatures of 60-100°C and pressures of 1-10 MPa, which are milder than conventional processes. This parameter change allows for simplified purification requirements while maintaining high productivity for ethylene and propylene production.
Solution Approach 2:
The patent employs a catalyst system that can operate effectively with minimal purification requirements, essentially treating the catalyst as a consumable that tolerates impurities. This approach replaces complex, expensive purification systems with a more economical catalyst-based solution.
3Device complexity
If pyrolysis plastic oil is directly used in oligomerization, then process simplicity is maintained, but catalyst lifetime is reduced and reaction efficiency decreases
Solution Approach 1:
The patent applies preliminary purification action to the pyrolysis plastic oil before it enters the oligomerization reactor. By removing sulfur and nitrogen compounds in advance, the catalyst is protected from poisoning, extending its lifetime and maintaining high reaction efficiency throughout the process.
Solution Approach 2:
The patent applies preliminary anti-action by preemptively removing harmful sulfur and nitrogen compounds that would otherwise poison the catalyst. This preventive measure protects the catalyst before it can be damaged, maintaining both process simplicity and catalyst longevity.
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
Effectively removes dienes, allowing pyrolysis plastic oil to be used in steam crackers, producing valuable olefins and aromatics while forming oligomeric products that can be further processed into resins or adhesives.
Implementation Method 1
a pyrolysis unit configured to produce pyrolysis plastic oil from waste plastic
Implementation Method 2
a purification unit configured to purify the pyrolysis plastic oil
Implementation Method 3
an oligomerization unit configured to produce ethylene and propylene from the purified pyrolysis plastic oil
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The disclosure relates to the purification and treatment of oil produced from the liquefaction of waste polymer like for instance the pyrolysis of waste plastic via the polymerization of dienes prior to further treatments.