JPS6150996B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for liquefying coal, and in particular, it is possible to obtain liquefied coal oil in high yield by hydrogenating and liquefying a raw material slurry consisting of coal powder and a solvent at high temperature and high pressure in the presence or absence of a catalyst. Concerning a coal liquefaction method. Generally, when producing coal liquefied oil from coal by the solvent extraction hydrogenation liquefaction method, a solvent is first added to coal powder to form a slurry, and this raw material slurry is mixed with hydrogen or a catalyst is further added and preheated. After that, the coal is introduced into a reaction tank and subjected to a hydrogenation reaction at high temperature and pressure to produce liquefied coal oil. However, in this conventional method, the raw material slurry, which has been preheated to around 200°C, is rapidly heated and pressurized to 300-650°C and 50-750°C atmospheric pressure in the reaction tank, so the reaction progresses rapidly and the coal molecules Chemical bonds that are easily thermally decomposed, such as ether bonds, carboxyl bonds, and carbonyl bonds, are cleaved almost simultaneously, but some of these radicals cannot be combined with hydrogen because the diffusion rate of hydrogen is slower than the rate of generation of the radicals. Many coals cannot be combined and instead react with nearby hydrocarbons, becoming heavier, resulting in the problem that the yield of solid coal liquefied material is higher than that of liquid material at room temperature. Moreover, once the bonds are broken and the hydrocarbons bond together, they become stronger than before, making liquefaction difficult. The present invention solves these problems and provides a method for liquefying coal that can efficiently conduct a hydrogenation and liquefaction reaction to obtain coal liquefied oil with a high yield. In producing coal liquefied oil by hydrogenating and liquefying raw material slurry at high temperature and high pressure in the presence or absence of a catalyst, two or more hydrogenation and liquefaction reactors connected in series are used, and the operating temperature of each reaction tank is adjusted. The chemical bonds in the coal molecules are broken in stages by setting a higher value in stages from the front to the rear, and causing the raw material slurry to flow sequentially from the front reaction tank to the rear reaction tank. A method for liquefying coal, characterized by carrying out a hydrogenation and liquefaction reaction. In other words, the present invention provides that the chemical structure of a coal molecule is such that aromatic hydrocarbons such as a benzene nucleus, naphthalene, and anthracene are sterically crosslinked via an alkyl group, an ether group, a carboxyl group, a carbonyl group, etc. We focused on the fact that the chemical bonds formed by these groups have different thermal cutting temperatures depending on the presence or absence of unsaturated bonds and the difference in atoms. By carrying out the hydrogenation and liquefaction reaction in stages, hydrogen is reliably bonded to the radicals generated by thermal decomposition. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an explanation will be given with reference to drawings showing an example of a hydrogenation and liquefaction reactor used to carry out the method of the present invention. First, raw coal powder is mixed with a solvent, mixed and stirred in a slurry tank 1 with or without the addition of a catalyst, for example, iron oxide, to form a slurry. After dehydration, the pressure is increased by a pump 2 and the mixture is pumped together with hydrogen to a preheater 3, where it is preheated to 150 to 250°C by exchanging heat with a combustion heater or a high-temperature fluid. After this preheated raw material slurry is further pressurized with hydrogen, it is subjected to a hydrogenation and liquefaction reaction, but according to the present invention, this hydrogenation and liquefaction reaction tank is in the first reaction tank 4a.
and the second reaction tank 4b... nth reaction tank 4n are connected in series, and the operating temperature of each reaction tank 4a, 4b... 4n is lower than the temperature of the first reaction tank 4a.
The higher the value, the higher the value is set. In addition, for large-scale processing, each reaction tank may be arranged in parallel or in series, and there may be two or more tanks with the same temperature.Also, the pressures may be kept constant or may be operated at different pressures. You can also do this. The operating temperature and operating pressure of the reaction tanks 4a, 4b...4n are determined by the reactive groups decomposed in each tank, and are generally within the range of 300 to 650°C and 50 to 750 atm, and may be set arbitrarily to satisfy the above conditions. is set to The preheated raw material slurry is introduced into the first reaction tank 4a, where the bonds that are easily broken by heat, such as ether bonds, in the coal molecules are cut to cause a hydrogenation and liquefaction reaction, and then the slurry is introduced into the second reaction tank 4b. in the third reaction tank, and the alkyl group in the third reaction tank.
In the fourth reaction tank, the aromatic ring cleavage reaction is carried out in sequence, starting with the one decomposed at a lower temperature. The coal liquefaction product thus produced is supplied to the gas-liquid separator 5, and hydrogen, water and
The vapor containing the solvent and the slurry are separated, and the slurry containing the hydrogenated and liquefied reactant is collected from the lower part of the gas-liquid separator 5, and is sent to the solid-liquid separator 6 via the pressure reducing valve 5, where it is separated into vapor containing the solvent and slurry. The ash content in the coal liquefaction product is separated and discharged from the bottom of the system, and the liquid content is removed using a conventional method.
Co―Mo/Al ₂ O ₃ , Ni―Mo/Al ₂ O ₃ , Ni―W/
A secondary hydrogenation and liquefaction reaction may be performed using a catalyst such as Al ₂ O ₃ to obtain liquefied coal oil. As described above, in carrying out hydrogenation under high temperature and high pressure according to the present invention, two or more reaction vessels connected in series are used, and their operating temperatures are set by changing them in stages according to the reactive group to be decomposed. As a result, the polymerization reaction due to insufficient diffusion of hydrogen during the hydrogenation reaction is suppressed, and light coal liquefied oil can be obtained in high yield. Example Australian Morwell lignite and creosote oil were mixed at a weight ratio of 1:3 to form a raw material slurry, and to this was added 2% powder catalyst (Fe 2 O ₃ ) and 5% powdered catalyst (Fe ₂ O 3 ) to the anhydrous ashless raw coal. of hydrogen, set the three reaction tanks connected in series under the following conditions, and caused the hydrogenation and liquefaction reaction to flow from the first reaction tank to the third reaction tank with an average residence time of 20 minutes each. The coal liquefaction product discharged from the third reactor was analyzed. The results are shown in Table 1. [Reaction tank operating conditions]

【table】

[Table] As a comparative example, the operating conditions of the above three reaction vessels are
Table 1 also shows the results when the same conditions were set as 430°C and 150 atm. As is clear from the above table, the yield of liquid products is more than twice as high in the sequential reaction method according to the present invention, and therefore, the yield of liquid products is more than twice as high as that of the sequential reaction method according to the present invention. Significant effects are expected, such as reduced loads and milder design conditions.

[Brief explanation of the drawing]

The figure is a system diagram of a hydrogenation and liquefaction reactor to which the method of the present invention is applied. 3 ~ Preheater, 4a, 4b,...4n ~ Reaction tank, 5
~ Gas-liquid separator.

Claims (1)

[Claims] 1. In producing coal liquefied oil by hydrogenating and liquefying a raw material slurry consisting of coal powder and a solvent at high temperature and high pressure in the presence or absence of a catalyst, two or more water bodies connected in series are used. Using a liquefaction reaction tank, the operating temperature of each reaction tank is set to be higher in stages from the front to the rear, and the raw material slurry is sequentially flowed from the front to the rear reaction tank. A coal liquefaction method characterized by stepwise breaking of chemical bonds in coal molecules to cause a hydrogenation and liquefaction reaction. 2. The method according to claim 1, wherein hydrogen is mixed into the raw material slurry at the inlet of each reaction tank. 3. The method according to claim 1, wherein the entire amount of hydrogen required for the hydrogenation and liquefaction reaction is mixed into the raw material slurry at the inlet of the foremost reaction tank. 4. The method according to any one of claims 1 to 3, wherein the raw material slurry is preheated before being introduced into the foremost reaction tank. 5. The method according to any one of claims 1 to 3, wherein the raw material slurry is preheated before being introduced into each reaction tank. 6. The method according to any one of claims 1 to 5, wherein the hydrogenation and liquefaction reaction is carried out by varying the operating pressure of each reaction tank.