Waste Plastic Pyrolysis Oil Refining to Prevent Ammonium Salt
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Solution Overview
Problem
Conventional methods for refining 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.
Innovation Solution
A method involving dehydration, hydrotreating, and distillation processes, including voltage application, use of a demulsifier, and a molybdenum-based hydrotreating catalyst, to minimize ammonium salt formation and maintain catalyst activity, while removing impurities like chlorine, nitrogen, and olefins.
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 applies preliminary action by introducing a sulfur source into the pyrolysis oil before hydrotreating begins. This sulfur source preemptively reacts with hydrogen to form H2S, which then reacts with nitrogen compounds to form sulfur-containing nitrogen compounds instead of ammonium salt. This preventive measure eliminates the harmful ammonium salt formation before it can occur during the main hydrotreating process.
Solution Approach 2:
The patent converts the potentially harmful interaction between hydrogen and nitrogen (which forms corrosive ammonium salt) into a beneficial reaction by introducing sulfur. The sulfur transforms the harmful nitrogen-hydrogen reaction into a sulfur-mediated reaction that produces non-corrosive sulfur-containing nitrogen compounds, effectively converting a harmful process into a beneficial one.
2Manufacturing precision
If conventional hydrotreating is performed 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 applies preliminary action by adding a sulfur source before the hydrotreating process begins. This sulfur source preemptively reacts with metal impurities and other particles that would otherwise adhere to the reactor walls during the heating and reaction process. By treating these particles in advance, the patent prevents adhesion issues and maintains reactor operation stability throughout the refining process.
3Device complexity
If waste plastic pyrolysis oil is directly refined, then the process is simple, but catalyst activity decreases rapidly due to impurity content
Solution Approach 1:
The patent applies preliminary action by introducing a sulfur source into the pyrolysis oil before it enters the hydrotreating reactor. This preliminary sulfur addition protects the catalyst from rapid deactivation by reacting with impurities first, thereby extending catalyst activity duration without adding complex pre-treatment units or multiple processing stages.
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 produces high-quality refined hydrocarbons with low impurity content, maintaining catalyst activity for a long duration and preventing particle adhesion, thus enhancing process efficiency and stability.
Implementation Method 1
a dehydration operation 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 hydrotreating a second mixed solution obtained by mixing the first mixed solution dehydrated in a dehydration operation and a sulfur source to produce refined oil from which impurities are removed
Implementation Method 3
a method of performing dechlorination, denitrification, and deoxygenation by reacting waste plastic pyrolysis oil with hydrogen in the presence of a hydrotreating catalyst
Implementation Method 4
a distillation operation distilling the refined oil from which impurities are removed in the hydrotreating operation
Data Source
AI summary
The present disclosure relates 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 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 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 reduced or prevented, and may produce refined hydrocarbons having a low content of impurities and a low content of olefins from waste plastic pyrolysis oil.