Ebullated Bed Hydroconversion for Plastic Pyrolysis Oil
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Solution Overview
Problem
The treatment of plastic pyrolysis oils and SRF pyrolysis oils is hindered by their high impurity content, leading to operability issues such as corrosion, coking, and catalytic deactivation in fixed-bed hydrotreating units.
Innovation Solution
A process involving the hydroconversion of a feedstock comprising a minor fraction of plastic pyrolysis oil and/or SRF pyrolysis oil, combined with a fossil-based heavy hydrocarbon fraction, in an ebullated bed or hybrid ebullated-entrained bed reactor, allowing for the scavenging of impurities and the production of higher-quality, lower-boiling point materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plastic pyrolysis oil and SRF pyrolysis oil are treated in fixed-bed hydrotreating units, then fuel and chemical products can be produced, but operability issues occur due to high impurity content causing corrosion, coking, and catalytic deactivation
Solution Approach 1:
The patent introduces an ebullated-bed hydroconversion unit as an intermediary process between pyrolysis oil production and fixed-bed hydrotreating. This intermediate step converts heavy pyrolysis oil into lighter hydrocarbons and removes impurities (silicon, chlorine, sulfur, nitrogen) before the feedstock enters fixed-bed hydrotreating units, thereby preventing corrosion, coking, and catalyst deactivation while enabling fuel and chemical production
Solution Approach 2:
The patent performs preliminary hydroconversion and impurity removal in an ebullated-bed reactor before the feedstock reaches fixed-bed hydrotreating units. By pre-converting heavy pyrolysis oil into lighter fractions and scavenging impurities in advance, the system avoids operability issues in downstream fixed-bed units while maintaining productivity
2Manufacturing precision
If plastic pyrolysis oil is co-treated with heavy hydrocarbon fraction in ebullated bed reactor, then impurity content is reduced and downstream processing is facilitated, but the process complexity increases
Solution Approach 1:
The patent designs the ebullated-bed hydroconversion reactor to perform multiple functions simultaneously: (1) hydroconversion of heavy pyrolysis oil into lighter hydrocarbons, (2) removal of impurities (silicon, chlorine, sulfur, nitrogen) through catalyst interaction, and (3) production of feedstock suitable for fixed-bed hydrotreating. This multi-functionality achieves impurity reduction without proportionally increasing process complexity
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 process effectively reduces the content of impurities such as silicon and chlorine in the hydroconverted effluent, facilitating easier processing in downstream steps like fixed-bed hydrotreatment, while maintaining the stability of the unconverted fraction.
Implementation Method 1
a first step of hydroconversion of said feedstock in the presence of hydrogen in said first hydroconversion section to obtain a first hydroconverted effluent
Implementation Method 2
hydroconversion of a feedstock comprising a minor fraction of plastic pyrolysis oil and/or SRF pyrolysis oil, combined with a fossil-based heavy hydrocarbon fraction
Implementation Method 3
a step of fractionating all or some of said first hydroconverted effluent from step (b) or of said second hydroconverted effluent from step (d), in a fractionation section, to produce at least one heavy liquid product
Implementation Method 4
allowing for the scavenging of impurities and the production of higher-quality, lower-boiling point materials
Implementation Method 5
This process effectively reduces the content of impurities such as silicon and chlorine in the hydroconverted effluent
Data Source
AI summary
The present invention relative to a process for the hydroconversion of a feedstock including a fraction of less than 50% by weight of plastic and/or SRF pyrolysis oil (102) and a heavy hydrocarbon fraction (101) containing a portion of at least 50% by weight with a boiling point of at least 300° C. and containing sulfur and nitrogen. The hydroconversion uses one or more ebullated bed or hybrid ebullated-entrained bed reactors (20), and preferably two successive hydroconversion steps. The process according to the invention allows the production of higher-quality, lower-boiling materials, for example for the production of fuels or chemical compounds for the petrochemical industry, with improved yields of certain cuts and while allowing facilitated processing of the hydroconverted products in downstream steps such as fixed-bed hydrotreatment and while maintaining good stability of the unconverted fraction.