CN-121975552-A - Preparation method of coal-based high-density fuel

Abstract

The invention discloses a preparation method of coal-based high-density fuel, which comprises a step A alkylation reaction, a step B hydrogenation saturation reaction and a step C isomerism rearrangement reaction, or only comprises the step B hydrogenation saturation reaction and the step C isomerism rearrangement reaction, or only comprises the step C isomerism rearrangement reaction. The invention provides a novel process for preparing coal-based fuel by combining the traditional process with heterogeneous rearrangement, which further regulates and controls the fuel molecules after hydrogenation saturation or alkylation, optimizes the substitution degree, the fusion degree and the configuration of the fuel molecules, and greatly improves the fuel performance. The invention can prepare the coal-based high-density fuel with high density, high heat value, high heat sink, high thermal oxidation stability, low viscosity and low freezing point through the multi-step synergistic process of alkylation, hydrogenation saturation and isomerism rearrangement, breaks through the limitation that the prior art can only optimize single or few performance indexes, and the product can meet the severe use requirements of high-performance aircrafts and engines on special fuels.

Inventors

• LI GUOZHU
• LIU YANG
• ZHANG XIANGWEN

Assignees

• 天津大学

Dates

Publication Date

20260505

Application Date

20260204

Claims (10)

1. 1. The preparation method of the coal-based high-density fuel is characterized by comprising the step A alkylation reaction, the step B hydrogenation saturation reaction and the step C isomerism rearrangement reaction, or only comprising the step C isomerism rearrangement reaction; Wherein: The alkylation reaction is carried out by taking coal-based liquid product as raw material, cycloolefin or cyclic alcohol as alkylating agent, molecular sieve or modified phosphotungstic acid as reaction catalyst, carrying out alkylation reaction, centrifugally filtering the alkylated product, and distilling out light component by atmospheric and vacuum distillation/rectification to obtain alkylated coal-based liquid product; b, carrying out hydrogenation saturation reaction, namely carrying out hydrogenation saturation reaction by taking a coal-based liquid product or the alkylated coal-based liquid product obtained in the step A as a raw material and a supported metal catalyst as a reaction catalyst, and carrying out centrifugal filtration on the product obtained after the hydrogenation saturation reaction to obtain a coal-based liquid product containing multicycloparaffins and alkane; and C, carrying out an isomerism rearrangement reaction by taking the coal-based liquid product or the coal-based liquid product containing the polycyclic alkane and the alkane obtained in the step B as a raw material and an acid catalyst as a reaction catalyst, and filtering and washing the product after the isomerism rearrangement reaction to obtain the fuel product coal-based high-density fuel.
2. 2. The method according to claim 1, wherein in step a, step B, and step C, the coal-based liquid product comprises coal-based diesel, coal-based kerosene, coal tar, and coal direct liquefaction oil.
3. 3. The method according to claim 1, wherein in step a, the aromatic hydrocarbon content in the coal-based liquid mixture is analyzed, and the mass of the alkylating agent to be added is calculated by measuring the molecular structure and content of aromatic hydrocarbon in the coal-based liquid product by a gas chromatograph-mass spectrometer.
4. 4. The method according to claim 1, wherein in the step a, the alkylation reaction catalyst comprises an HY molecular sieve or USY molecular sieve or micropore-mesopore composite molecular sieve or modified phosphotungstic acid having FAU structure.
5. 5. The process of claim 1, wherein in step a, the alkylating agent comprises cyclopentene, cyclohexene, norbornene, norbornadiene, cyclohexanol, cyclopentanol, and norbornyl alcohol.
6. 6. The process of claim 1, wherein in step A, the alkylation reaction is carried out at a temperature of 100-200deg.C and a pressure of 0-4MPa for 1-2h.
7. 7. The method of claim 1, wherein in step B, the catalyst comprises Ru/C or Pd/Al 2 O 3 or raney nickel or Pd/HY.
8. 8. The process according to claim 1, wherein in step B, the hydrogenation is carried out at a temperature of 120-220 ℃ under a pressure of 2-6MPa for 3-18 hours.
9. 9. The method of claim 1, wherein in step C, the acidic catalyst comprises AlCl 3 、AlCl 3 ionic liquid, laY molecular sieve.
10. 10. The process according to claim 1, wherein in the step C, the isomerization rearrangement reaction is carried out under a temperature of 40-220 ℃ and a pressure of 0-6MPa for 1-20 hours.

Description

Preparation method of coal-based high-density fuel Technical Field The invention relates to the technical field of petroleum and chemical engineering, in particular to the field of fuel chemistry and special fuel preparation, and more particularly relates to a preparation method of coal-based high-density fuel. Background With the rapid development of advanced aerospace vehicles, the requirements for high-density fuels are increasing. The greater the energy density of the fuel, the higher the heat released per unit volume of fuel after combustion. Therefore, it is necessary to increase the density of the fuel to increase the volumetric heating value of the fuel, and to ensure a higher mass heating value while ensuring a high volumetric heating value, and also to ensure good thermal oxidation stability and good low temperature performance of the fuel. Compared with alkane and monocycloalkane, the polycyclic alkane has higher density and larger volumetric heat value, is the main component of high-density fuel, and has wide application in the aerospace field. For example, JP-900 is based on decalin and JP-10 is based on pendant tetrahydrodicyclopentadiene. The coal resource reserves in China are rich, the petroleum resources are relatively short, but the existing high-density fuel mainly comes from the petroleum resources. The coal-based liquid product prepared from coal tar and/or coal direct liquefied oil has complex composition, and the main components comprise benzene, indene, naphthalene, acenaphthene, fluorene, phenanthrene, anthracene and the like, and branched chains and hydrogenated derivatives thereof, and after hydrogenation saturation, the viscosity is often higher, the freezing point is higher, the heat value is lower, the thermal oxidation stability is poorer, and the application requirements of aerospace fuel are difficult to reach. The coal-based liquid products, such as coal-based diesel oil, coal-based kerosene, coal tar, direct coal liquefaction oil and other unconventional raw materials, can be used as effective substitutes for petroleum resources to produce high-density fuel and can be used as strategic reserves to ensure national energy safety. Coal-based liquid products such as coal-based diesel oil, coal-based kerosene, coal tar and direct coal liquefaction oil contain a large amount of polycyclic hydrocarbon and polycyclic aromatic hydrocarbon, and aviation and aerospace fuels with high thermal oxidation stability, high heat value and low temperature performance are produced in a hydrogenation saturation mode, however, the density of the fuel produced by hydrofining the coal-based liquid products is about 0.85g/cm 3, and the high energy density requirement is difficult to reach. The method is characterized in that the molecular structure of the coal-based fuel is required to be regulated, the cyclization degree and substitution degree of the coal-based fuel are moderately increased, so that the density of the fuel is improved, for example, the alkylation reaction is carried out on the coal-based molecule, a new ring structure is introduced, then the saturated product is subjected to hydrogenation saturation, and the isomerism rearrangement is carried out on the saturated product to regulate and control the molecular structure of the fuel, so that the coal-based high-density fuel with high density, high heat value, high thermal oxidation stability, low viscosity and low freezing point is prepared. The existing preparation process of the coal-based high-density fuel takes a coal-based liquid product as a raw material and mainly comprises two core processes, namely, directly preparing the fuel by carrying out hydrotreating (including hydrodenitrogenation, hydrofining, hydrogenation saturation and the like) after rectification and cutting, and preparing the high-density fuel by carrying out alkylation reaction on aromatic hydrocarbon in the product and then carrying out hydrogenation saturation reaction after rectification and cutting. The prior art has the problems that firstly, the fuel prepared by the rectification-hydrogenation treatment process has the defects of low density, low heat sink, high freezing point, poor low-temperature performance and poor thermal oxidation stability, and secondly, the rectification-alkylation-hydrogenation saturation process can improve the fuel density, but the product still has the problems of low heat sink, poor thermal oxidation stability and high viscosity, the requirements of high-performance aircrafts and engines cannot be met, in the process, the polycyclic aromatic hydrocarbon (such as indenes, naphthalenes, acenaphthenes, fluorenes and the like) with the ring number more than or equal to 2, which is rich in the coal-based liquid product, has large molecular size, difficult diffusion mass transfer, easy coking and carbon deposition in the reaction, and the traditional ZSM-5, ZSM-35 and other microporous catalysts are difficult to realize high-ef