Waste Plastic Pyrolysis Oil Refining to Prevent Ammonium Salt
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Solution Overview
Problem
Existing methods for producing refined hydrocarbons from waste plastic pyrolysis oil face issues such as the formation of ammonium salt (NH4Cl), which causes reactor corrosion and reduces process efficiency, and the adhesion of impurity particles, leading to operational challenges and reduced durability.
Innovation Solution
A method involving dehydration, hydrotreating, and isomerization processes, including voltage application, water washing, and the use of a molybdenum-based hydrotreating catalyst, to minimize ammonium salt formation and impurity adhesion, while maintaining catalyst activity and refining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If waste plastic pyrolysis oil is hydrotreated with hydrogen in the presence of a hydrotreating catalyst, then impurities such as chlorine, nitrogen, and oxygen are removed, but ammonium salt (NH4Cl) is formed causing reactor corrosion and process issues
Solution Approach 1:
The patent divides the hydrotreating process into two separate stages: first removing chlorine to prevent HCl formation, then removing nitrogen. This segmentation prevents the simultaneous presence of HCl and NH3 that would form corrosive ammonium salt, resolving the contradiction between effective impurity removal and avoiding harmful byproducts
Solution Approach 2:
The patent applies preliminary dechlorination before hydrotreating. By removing chlorine first through adsorption or preliminary treatment, the subsequent hydrotreating process does not generate HCl that would react with nitrogen compounds to form ammonium salt, thus preventing the harmful effect before it occurs
2Manufacturing precision
If conventional hydrotreating is used to remove impurities, then refined oil is produced, but adhesion of impurity particles occurs inside the reactor causing process issues
Solution Approach 1:
The patent performs preliminary filtration and dehydration of waste plastic pyrolysis oil before hydrotreating to remove particles and water that would cause adhesion. This preliminary action prevents impurity adhesion in the reactor while maintaining refining efficiency
Solution Approach 2:
The patent introduces an intermediary filtration system with specific pore size filters between the pyrolysis unit and hydrotreating reactor. This intermediary component captures impurity particles before they enter the reactor, preventing adhesion issues while allowing the refining process to proceed efficiently
3Productivity
If waste plastic pyrolysis oil is blended with high-value fuel, then energy recovery is achieved, but limited blending amount is allowed due to high impurity content
Solution Approach 1:
The patent applies advanced hydrotreating parameters including optimized temperature (300-400°C), pressure (50-150 bar), and hydrogen-to-oil ratio to achieve deep impurity removal. These parameter changes enable production of high-quality refined oil with sufficient blending quantity for high-value fuels
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 reduces impurities like chlorine, nitrogen, and olefins, ensuring stable, long-term operation with high-quality refined hydrocarbons suitable for blending with high-value fuels.
Implementation Method 1
a dehydration operation which includes applying a voltage to a first mixed solution obtained by mixing waste plastic pyrolysis oil, washing water, and a demulsifier to dehydrate the first mixed solution
Implementation Method 2
a hydrotreating operation including hydrotreating a second mixed solution obtained by mixing the dehydrated first mixed solution from the dehydration operation and a sulfur source to produce refined oil from which impurities are removed
Data Source
AI summary
Embodiments of the present disclosure relate to a method and system for producing refined hydrocarbons from waste plastic pyrolysis oil. The method and system for producing refined hydrocarbons from waste plastic pyrolysis oil according to the embodiments of the present disclosure may minimize formation of an ammonium salt (NH4Cl) and may prevent an adhesion phenomenon of impurity particles in a reactor in a refining process of waste plastic pyrolysis oil containing impurities including chlorine and nitrogen. In addition, the method and system for producing refined hydrocarbons according to the embodiments of the present disclosure may have excellent refining efficiency and may implement a long-term operation of a process because deactivation of a catalyst used in the process is prevented, and may produce refined hydrocarbons having a low content of impurities and a low content of olefins from waste plastic pyrolysis oil.