Hydrocracking Heavy Distillates Using Supercritical Aromatic Solvent
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Solution Overview
Problem
Conventional hydrocracking processes for upgrading heavy hydrocarbon distillates to high value-added products, such as middle distillates, face challenges including high hydrogen pressure requirements, insufficient conversion efficiency, and coke formation, especially when using conventional supercritical solvents.
Innovation Solution
A hydrocracking process utilizing a supercritical xylene-containing solvent with a hydrogenation catalyst, specifically a mixture of xylene, ethylbenzene, and toluene, at reduced hydrogen pressures, to convert heavy hydrocarbon distillates into low-boiling hydrocarbons like middle distillates, while minimizing coke formation and optimizing catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional supercritical solvents are used for hydrocracking heavy hydrocarbon distillates, then the process can operate at reduced hydrogen pressure, but the conversion efficiency is insufficient and coke formation occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the supercritical solvent from conventional options (water, n-alkanes, cycloalkanes) to an aromatic solvent system containing xylene (30-70 wt%), toluene (10-40 wt%), and ethylbenzene (5-20 wt%). This parameter change in solvent composition enables effective hydrocracking at reduced hydrogen pressure (30-150 bars) while maintaining high conversion efficiency and minimizing coke formation, directly resolving the technical contradiction.
2Ease of operation
If conventional supercritical solvents are used for hydrocracking, then operation conditions can be simplified, but coke formation increases and catalyst performance deteriorates
Solution Approach 1:
The aromatic solvent mixture acts as an intermediary substance that mediates between the heavy hydrocarbon distillate and the hydrogenation catalyst. The solvent's aromatic structure (xylene, toluene, ethylbenzene) provides a chemical environment that prevents coke formation on the catalyst surface while maintaining ease of operation at reduced hydrogen pressure. The solvent intermediates the reaction process, preventing direct harmful interactions between the feedstock and catalyst that would otherwise lead to coke deposition.
3Stress or pressure
If reduced hydrogen pressure is applied, then operational safety and cost improve, but conversion efficiency of heavy distillates decreases
Solution Approach 1:
The patent fundamentally changes the solvent composition parameters to an aromatic-based system (xylene 30-70 wt%, toluene 10-40 wt%, ethylbenzene 5-20 wt%) that maintains high conversion efficiency at reduced hydrogen pressure (30-150 bars). This parameter change in the reaction medium's chemical nature compensates for the reduced hydrogen pressure, enabling both improved safety/cost and maintained productivity simultaneously.
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 process effectively converts heavy hydrocarbon distillates into high value-added products at lower hydrogen pressures, enhancing the selectivity and yield of middle distillates, and reducing coke formation, thus improving the efficiency and economic viability of the hydrocracking process.
Implementation Method 1
a hydrocracking process utilizing a supercritical xylene-containing solvent with a hydrogenation catalyst
Implementation Method 2
with a hydrogenation catalyst, specifically a mixture of xylene, ethylbenzene, and toluene, at reduced hydrogen pressures, to convert heavy hydrocarbon distillates into low-boiling hydrocarbons
Implementation Method 3
to convert heavy hydrocarbon distillates into low-boiling hydrocarbons like middle distillates
Data Source
AI summary
Specific embodiments of the present invention provide a hydrocracking process for converting low value-added heavy hydrocarbon distillates into high value-added hydrocarbon distillates using a supercritical solvent as a medium.