Pyrolysis Oil Purification via Char Adsorption
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Solution Overview
Problem
Pyrolysis oil produced from mixed plastics contains substantial contaminants like chlorides, which cause fouling and corrosion in equipment during further processing, making removal costly, difficult, and time-consuming.
Innovation Solution
The process involves mixing pyrolysis oil with char derived from the pyrolysis of plastic to remove chloride compounds, forming a purified pyrolysis oil that can be cracked to produce olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pyrolysis oil is diluted with naphtha at high dilution ratio to reduce contaminant effects, then equipment fouling and corrosion are decreased, but processing cost and complexity increase
Solution Approach 1:
The patent extracts and removes chloride contaminants from pyrolysis oil through a dedicated purification step using activated carbon or hydroxide treatment before cracking, rather than diluting the oil. This extraction approach eliminates the harmful chlorides while maintaining the concentration and value of the pyrolysis oil, avoiding the complexity of high-ratio dilution processes.
Solution Approach 2:
The patent applies preliminary purification treatment to remove chlorides from pyrolysis oil before the cracking process. By performing this cleanup action in advance, the oil is prepared for cracking without requiring subsequent dilution, thereby simplifying the overall process while protecting equipment from fouling and corrosion.
2Object-affected harmful factors
If hydrotreatment is applied to convert chlorinates into HCL for removal, then chloride contamination is reduced, but processing time and cost increase
Solution Approach 1:
The patent employs activated carbon or hydroxide as a disposable purification medium that can be easily added to the pyrolysis oil, performs rapid chloride removal, and then discarded or regenerated. This approach replaces time-consuming hydrotreatment with a simpler, faster purification step using readily available materials.
Solution Approach 2:
The patent changes the purification approach from chemical hydrotreatment to physical adsorption or neutralization using activated carbon or hydroxide. This parameter change in the purification method dramatically reduces processing time while achieving effective chloride removal, avoiding the lengthy hydrotreatment process.
3Productivity
If pyrolysis oil containing chlorides is directly cracked, then processing efficiency is maintained, but equipment reliability deteriorates due to fouling and corrosion
Solution Approach 1:
The patent introduces an intermediary purification step using activated carbon or hydroxide between pyrolysis oil production and cracking. This intermediary treatment removes harmful chlorides while preserving the oil's cracking potential, allowing efficient processing to continue without compromising equipment reliability.
Solution Approach 2:
The patent performs preliminary chloride removal before cracking to protect equipment. By preparing the oil in advance through purification, the subsequent cracking process can proceed efficiently without interruptions from equipment fouling or corrosion, maintaining both productivity and reliability.
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 removes at least 20 wt.% of chlorides from pyrolysis oil, producing a purified oil that can be safely cracked to produce high-value chemicals like olefins, thereby reducing equipment damage and processing costs.
Implementation Method 1
mixing the pyrolysis oil with char derived from pyrolysis of plastic and thereby remove at least some material from the pyrolysis oil
Implementation Method 2
Pyrolysis of plastics (e.g., mixed waste plastics) is a process that involves subjecting the plastics to high temperature such that the plastic decomposes to form pyoil
Data Source
AI summary
Systems and methods for removing contaminants from pyrolysis oil are disclosed. The removal of the contaminants, such as chlorides, involves mixing the pyrolysis oil with char, in a mixing unit, wherein the char was formed as a by-product of the pyrolysis of plastic to produce pyoil.