Recycling Hydrogen-Donating Solvent for Direct Coal Liquefaction
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Solution Overview
Problem
Existing recycling solvents for direct coal liquefaction face challenges such as high hydrogen consumption, severe process conditions, insufficient hydrogen-donating capacity, and complex technological processes.
Innovation Solution
A method for preparing a recycling hydrogen-donating solvent involves first fractionating direct coal liquefaction oil into medium and heavy oils, followed by staged hydrogenation reactions in suspended and fixed bed reactors, and subsequent fractionation to blend medium-temperature and high-temperature solvent oils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep hydrogenation treatment is performed on recycling solvent to improve hydrogen-donating capacity, then hydrogen-donating capacity is improved, but hydrogen consumption increases and process conditions become more severe
Solution Approach 1:
The invention changes the chemical composition parameters of the recycling solvent by controlling the ratio of aromatic hydrocarbons to hydrogenated aromatic hydrocarbons (specifically setting aromatic carbon ratio between 0.35-0.55 and hydrogen-donating index between 18-25). This parameter optimization allows the solvent to achieve adequate hydrogen-donating capacity without requiring excessive deep hydrogenation treatment, thereby reducing hydrogen consumption while maintaining reliable hydrogen donation function.
2Reliability
If deep hydrogenation treatment is performed on recycling solvent to improve hydrogen-donating capacity, then hydrogen-donating capacity is improved, but process conditions become more severe
Solution Approach 1:
The invention optimizes the solvent's chemical parameters (aromatic carbon ratio and hydrogen-donating index) to achieve the desired hydrogen-donating capacity without subjecting the solvent to excessively severe hydrogenation conditions. By carefully controlling these composition parameters, the process can operate at moderate temperatures and pressures while still producing a solvent with adequate hydrogen donation ability.
3Reliability
If conventional deep hydrogenation methods are used to prepare recycling solvent, then hydrogen-donating capacity is improved, but technological process becomes more complex
Solution Approach 1:
The invention focuses on optimizing the chemical composition parameters of the recycling solvent (aromatic carbon ratio and hydrogen-donating index) rather than implementing complex multi-stage hydrogenation processes. This parameter-based approach simplifies the technological process flow while still achieving the target hydrogen-donating capacity, avoiding the need for elaborate process equipment and operations.
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 approach results in a recycling solvent with enhanced hydrogen-donating capacity, reduced hydrogen consumption, and simplified process flow, improving the efficiency and stability of direct coal liquefaction processes.
Implementation Method 1
the solvent used is a mixed oil of medium-temperature oil and high-temperature oil produced by direct coal liquefaction itself in a certain ratio, called recycling solvent... the important chemical effects of providing hydrogen to the pyrolysis products of coal and stabilizing the low molecular pyrolysis products
Implementation Method 2
the solvent not only has physical effects of slurrying the solid coal powder so as to improve the transportation and thermodynamic properties of a material and dissolving the pyrolysis products of coal
Data Source
AI summary
The invention provides a recycling hydrogen-donating solvent for direct coal liquefaction and a preparation method therefor and use thereof, the recycling hydrogen-donating solvent provided by the preparation method of the invention can be used for obtaining the recycling hydrogen-donating solvent with good hydrogen-donating capacity through a relatively simple process flow. The preparation method comprises the following steps: 1) carrying out first fractionation on a direct coal liquefaction oil to obtain liquefied medium oil and liquefied heavy oil; 2) feeding the liquefied heavy oil into a first hydrogenation reactor and carrying out a first-stage hydrogenation reaction; 3) feeding the liquefied medium oil and the liquefied heavy oil subjected to the first-stage hydrogenation reaction in the step 2) into a second hydrogenation reactor, and carrying out a second-stage hydrogenation reaction to obtain hydrogenated product oil; 4) performing second fractionation on the hydrogenated product oil to obtain medium-temperature solvent oil and high-temperature solvent oil; and 5) mixing the medium-temperature solvent oil and the high-temperature solvent oil to prepare the recycling hydrogen-donating solvent.