Pyrolysis Oil Hydroconversion Process for Refinery Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to find a way to profitably exploit pyrolysis oil from steam cracking units, which is typically used only as fuel due to its high-temperature reaction products and refractory molecular structures like asphaltenes and resins, without complicating existing refinery installations or operating conditions.
Innovation Solution
A hydroconversion process that combines pyrolysis oil with a conventional heavy hydrocarbon feedstock, controlling their feed temperatures to prevent polymerization and fouling, and includes steps like hydrocracking, fractionation, and deasphalting to convert pyrolysis oil into light finished products, stabilizing hydroconversion effluents, and reducing asphaltene precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pyrolysis oil is used as fuel for power generating units, then energy recovery is achieved, but the valuable hydrocarbon components are wasted and environmental impact increases
Solution Approach 1:
The patent converts the harmful aspect of pyrolysis oil (high asphaltene content causing fouling) into a benefit by using it as a feedstock for hydroconversion to produce valuable light hydrocarbon products. The process transforms the problematic heavy molecular structures into useful chemical products through catalytic hydrocracking and hydroisomerization reactions.
Solution Approach 2:
The patent changes the physical and chemical parameters of pyrolysis oil by controlling hydroconversion conditions (temperature, pressure, hydrogen partial pressure, catalyst type) to convert heavy asphaltene-rich feedstock into lighter, more valuable hydrocarbon products with different physical properties and uses.
2Productivity
If pyrolysis oil is processed through hydroconversion, then valuable light products are produced, but the complexity of refinery installations increases
Solution Approach 1:
The patent makes existing refinery units multi-functional by enabling them to process both conventional petroleum feedstocks and pyrolysis oil. The hydroconversion unit is designed to handle variable feedstock compositions, allowing the same infrastructure to produce light products from different feed sources without requiring completely separate dedicated facilities.
Solution Approach 2:
The patent merges the pyrolysis oil processing stream with the existing hydroconversion unit, combining the treatment of conventional heavy hydrocarbons and pyrolysis oil in a unified process flow. This integration allows shared infrastructure for catalyst handling, hydrogen supply, and product separation, reducing overall system complexity.
3Productivity
If pyrolysis oil is fed at high temperature to hydroconversion reactor, then conversion efficiency improves, but polymerization and fouling occur
Solution Approach 1:
The patent optimizes the temperature parameter in the hydroconversion reactor to a specific range (200-400°C) that balances conversion efficiency with preventing polymerization. This parameter optimization ensures that the reaction proceeds sufficiently fast to produce valuable products while staying below the threshold where asphaltene polymerization and fouling become problematic.
Solution Approach 2:
The patent uses hydrogen as an intermediary substance that facilitates the hydroconversion reaction while preventing direct polymerization of asphaltene molecules. The hydrogen atmosphere and catalytic system promote hydrogenation reactions that saturate double bonds and prevent the condensation reactions leading to polymerization and fouling.
4Duration of action of stationary object
If asphaltenes are present in hydroconversion effluent, then process continuity is maintained, but deposit formation occurs in production lines
Solution Approach 1:
The patent changes the chemical composition parameters of the effluent by controlling the hydroconversion to produce products with reduced asphaltene content. The process parameters (temperature, pressure, hydrogen partial pressure, catalyst selection) are optimized to maximize the conversion of asphaltenes into soluble hydrocarbon products, reducing their tendency to precipitate and form deposits in downstream equipment.
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 converts pyrolysis oil into valuable light products while stabilizing hydroconversion unit effluents, preventing fouling, and improving overall process performance without significant modifications to existing refinery infrastructure.
Implementation Method 1
a) a step of hydroconverting said feedstocks in at least one reactor, in the presence of hydrogen and of at least one hydroconversion catalyst
Implementation Method 2
in the presence of hydrogen and of at least one hydroconversion catalyst
Implementation Method 3
b) a step of separating at least a portion of the hydroconverted liquid effluent obtained from step a) into at least a naphtha fraction, a gas oil fraction, a vacuum gas oil fraction and an unconverted residue fraction
Implementation Method 4
c) a hydrocracking step in a fixed-bed reactor in the presence of a catalyst for hydrocracking at least a portion of the vacuum gas oil fraction obtained from step b)
Implementation Method 5
d) a step of fractionating at least a portion of the hydrocracked liquid effluent obtained from step c) into a naphtha fraction, a gas oil fraction and an unconverted vacuum gas oil fraction
Data Source
AI summary
The invention relates to a process for converting a feedstock comprising pyrolysis oil and a heavy hydrocarbon-based feedstock, with:a) a step of hydroconversion in a reactor;b) a step of separating the liquid effluent obtained from step a) into a naphtha fraction, a gas oil fraction, a vacuum gas oil fraction and an unconverted residue fraction;c) a step of hydrocracking of the vacuum gas oil fraction;d) a step of fractionating the hydrocracked liquid effluent obtained from step c) into a naphtha fraction, a gas oil fraction and a vacuum gas oil fraction;e) a step of steam cracking of a portion of the naphtha fraction obtained from step d);f) a step of fractionating at least a portion of the steam-cracked effluent obtained from step e);g) a step in which the pyrolysis oil fraction obtained from step f) is sent into step a).