JP2970677B2 - Coal liquefaction method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for liquefying coal, and more particularly to a method for hydrogenating and distilling raw coal such as lignite to obtain an oil component, and further to obtain a distillate residue oil component. A method for liquefying coal.

(Conventional technology) As a conventional coal liquefaction method, an extraction hydrogenation method is typical. In this method, the raw coal is hydrogenated and liquefied, and the liquefied product is distilled to separate it into naphtha, an oil such as a medium oil, and a residual residue, and the residue is treated with a solvent having a relatively low boiling point, such as naphtha. It is subjected to a demineralization treatment to separate it into an oil solution and an insoluble concentrate slurry. As the solvent, for example, naphtha having an average boiling point of 155 to 220 ° C is used.

Oil solution after demineralization treatment (hereinafter referred to as solution)
Means that after recovering the solvent by distillation etc., the dissolved heavy components
It is often lightened by secondary hydrogenation and recovered as an oil by distillation. On the other hand, the insoluble content concentrated slurry is composed of an insoluble content (ash content, etc.) and a solution, and is used for separating and recovering a solvent for deashing treatment from the solution. Generally, the separation and recovery
Insoluble matter concentrated slurry is introduced into a distillation column, and the distillation is performed by a distillation method utilizing a difference in boiling points of the components of the slurry.

(Problems to be Solved by the Invention) By the way, the solution in the above-mentioned slurry still contains a large amount of heavy liquefied substances that can become oil components. The heavy liquefied product is composed of various components, and includes components that can be distilled even at a high boiling point and components that are difficult to distill. Based on whether or not it is soluble in benzene, the benzene-soluble component is the former and the benzene-insoluble component is the latter.

When the slurry is distilled at a relatively low temperature, the solvent having a relatively low boiling point in the slurry evaporates and is recovered from the top of the distillation column. Collected from the department. However, high boiling components such as the heavy liquefied products cannot be separated from insolubles. In order to separate and recover such high-boiling components from insolubles, it is necessary to further raise the distillation temperature.

However, when the distillation temperature is increased, the heavy liquefied material melts at a high temperature and is composed of a substance that easily undergoes polycondensation. In addition, there is a problem that fluidity is lost due to polycondensation, and furthermore, carbonization is partially performed, and extraction and transport from the bottom of the column become extremely difficult.

As a countermeasure, a method in which the boiling point of the components in the heavy liquefied product is reduced by increasing the degree of vacuum in the distillation column, and distillation is performed in a temperature range (relatively low temperature) where the loss of fluidity does not occur. However, such a method does not significantly increase the separation and recovery rate of the solution, and has a problem that it is difficult to substantially recover heavy liquefied matter.

Although attempts have been made to recover solvents,
The recovery rate was not always high enough.

The present invention solves the above-mentioned problems of the prior art, and can perform separation and recovery of the solution from the slurry at a high recovery rate,
Accordingly, it is an object of the present invention to provide a method for liquefying coal, which can improve the yield of liquefied oil and can recover particularly a solvent at an extremely high recovery rate.

(Means for Solving the Problems) In order to achieve the above object, a coal liquefaction method according to the present invention has the following configuration.

That is, the method according to claim 1 hydrogenates the raw coal,
Distillation to separate the oil and residual residue, the residue is subjected to a solvent demineralization treatment to separate into an oil solution and an insoluble concentrate slurry, and the coal is recovered from the slurry by separating the solution from the insoluble matter and recovering the solution. A liquefaction method, wherein the slurry in a high-speed fluidized bed using porous particles heated to 400 to 650 ° C. is sprayed, and the solvent in the slurry is evaporated and then condensed and taken out as a liquid. A coal liquefaction method comprising separating and recovering heavy liquefied matter dissolved in coal.

The method according to claim 2, wherein the porous particles of the fluidized bed are
The coal liquefaction method according to claim 1, wherein the coal is liquefied and heated to 400 to 550C.

The method according to claim 3 is the method according to claim 1, wherein the porous particles of the fluidized bed are amorphous alumina or zeolite having a particle size of 100 to 300 µm.

The method according to claim 4, wherein the moving speed of the fluidized bed is 5 or less.
The method for liquefying coal according to claim 1, wherein the pressure is -20 cm / sec.

The method according to claim 1, wherein the slurry is subjected to distillation at a normal pressure or reduced pressure at a temperature of 300 ° C. or less at a low boiling point to concentrate insolubles in the slurry, and then sprayed on the fluidized bed. It is a coal liquefaction method of the description.

(Operation) As described above, the method for liquefying coal according to the present invention employs a method of separating and recovering a solution from slurry at 400 to 650 ° C.
Since the slurry is sprayed onto a high-speed fluidized bed using porous particles heated to a low temperature, the slurry is heated, and the solution in the slurry is instantaneously evaporated. This evaporate can be condensed and removed as a liquid. Thus, the solution in the slurry can be recovered. Here, since the heating temperature of the porous particles is set to 400 to 650 ° C. as described above, the solvent used for demineralization can be completely recovered, and dissolved in the solvent and contained in the heavy liquefied product. The recovery of distillable components can be very high,
Further, a part of the insoluble component which is difficult to recover by distillation can be thermally decomposed to improve the recovery rate.

When the concentration of the insolubles in the slurry is low, it is also possible to evaporate and recover the light boiling components in the solvent at a temperature of 300 ° C. or lower under normal pressure or reduced pressure, further concentrate the insolubles, and then spray the fluidized bed.

On the other hand, the residue after evaporation of the solution (evaporation residue) is adsorbed to the particles of the fluidized bed in a partially molten state, but since the particles are porous and each of them is flowing at a high speed, the particles are porous. No agglomeration of the particles occurs. Therefore, the fluidized bed particles to which the evaporation residue has been adsorbed can be easily recovered without any problem. The evaporation residue is a mixture of ash and heavy liquefied material (ash-containing heavy material), and the latter heavy liquefied material melts and has a binder effect, but does not clump. This is based on the fact that the porous particles adsorb to the inside of the particles, the amount of heavy liquefied material on the particle surface is small, and the particles flow at high speed.

Therefore, without any trouble as described above,
The solution can be separated and recovered from the slurry at a high recovery rate, and a part of the heavy liquefied material that has been discharged together with the insoluble matter is recovered, so that the liquefied oil yield can be improved. Note that the collected evaporation residue adsorption particles contain at least a benzene-insoluble component, and when the particles are heated at a high temperature and thermally decomposed, a pyrolysis oil (tar oil) and a pyrolysis gas (C _{1 to} C ₄
Hydrocarbon, H ₂ , CO, CO ₂ ). By doing so, the liquefied oil yield can be further improved, and useful resources such as H ₂ and CO can be obtained.

The heating temperature of the porous particles of the fluidized bed is operable for a time in the range of 300 to 650 ° C., but when the temperature is less than 400 ° C., the slurry heating temperature is reduced, and the liquefied oil yield is reduced. From the point where the recovery rate of the solvent decreases, 400 to 650
It must be in the range of ° C. At this time, if the temperature exceeds 500 ° C., a part of the solvent in the slurry and the heavy liquefied material is thermally decomposed, and the recovery rate as the solvent or the heavy liquefied material is reduced. . At this time, even if it is thermally decomposed, it is recovered as H ₂ and CO ₂ .

When using a low-speed fluidized bed instead of the high-speed fluidized bed,
The particles are adhered to each other by the melt evaporation residue, and the particles are agglomerated, which makes it difficult to operate the fluidized bed. In order to prevent this, a high-speed fluidized bed is used.

It is desirable that the moving speed of the high-speed fluidized bed be 5 to 20 cm / sec. Below 5 cm / sec, agglomeration of particles occurs, 20 c
If it exceeds m / sec, the heating temperature of the slurry decreases, the amount of evaporation decreases, and the liquefied oil yield decreases.

As the porous particles of the fluidized bed, amorphous alumina or zeolite can be used, and the particle size is desirably 100 to 300 μm. If it is less than 100 μm, the particles are too fine and the fluidization rate per unit bed height is low, so the particles move out of the fluidized bed and the function as a high-speed fluidized bed is deteriorated.
Above, the specific surface area is small, and the fluidization rate per unit bed height is high, which makes it difficult to control the bed surface of the bed, reduces the efficiency of heat transfer, and makes it difficult for instantaneous evaporation of the solvent in the slurry to occur. is there.

The coal liquefaction method according to the present invention is not limited to the one-stage liquefaction method, but may be applied to a two-stage liquefaction method or a three- or more-stage liquefaction method.

(Example) Example 1 FIG. 1 shows a schematic diagram of a process flow for separating and recovering a solution from a slurry according to Example 1.

First, a mixture of milled and dehydrated Morwell lignite, a catalyst and a solvent was first hydrogenated and distilled to separate naphtha, a medium oil and a distillation residue.

To the distillation residue, a decalcification solvent was added, and the temperature was raised to 250 ° C. and 50 atm. It was obtained by separating into an ash-enriched slurry and a supernatant. The ash-concentrated slurry contained 53% of a deashing solvent and 47% of ash-containing heavy substances. The ash-enriched slurry is introduced into the raw material storage tank (1).

The ash-enriched slurry was sprayed from a raw material storage tank (1) through a pressure reducing valve (9) at a pressure of 20 kg / cm ² onto a high-speed fluidized bed (3) at normal pressure. 50 to 50 porous particles in the fluidized bed (3)
200 μm amorphous alumina, heated. This heating, heating send N ₂ gas to boost the blower (2) by a preheater (8), followed by by introducing into the fluidized bed (3).

The sprayed slurry comes into contact with the heated porous particles, and the solvent in the slurry evaporates instantaneously. The evaporated solution (solvent and heavy liquefied matter) is discharged out of the system together with some fluidized particles, and introduced into the cyclone (4) in a heated atmosphere.

In the cyclone (4), only particles are collected. The evaporated solution is introduced into the condenser (5) and condensed, and then enters the condensed oil receiver (6) and is collected.

The fluidized particles adsorbed with the evaporation residue (unevaporated heavy liquefied material) having a slightly increased particle diameter are extracted outside the system from the lower part (7) of the fluidized bed.

The heating temperature of the porous particles is 300, 400, 500, 600
° C. The moving speed of the fluidized bed is 10cm / sec
I made it.

As a result, when the heating temperature of the porous particles was 300,400 ° C, some agglomeration of the particles in the fluidized bed was observed.However, agglomeration was achieved by evaporating a part of the solvent in advance and increasing the concentration of the solid matter in the slurry. It was suppressed and became operational. At 500 and 600 ° C, continuous operation of the fluidized bed could be stabilized without any trouble such as agglomeration of particles. That is, 500,60
At 0 ° C., the particles adsorbed with the evaporation residue were powdery and excellent in fluidity, so that the particles could be easily recovered from the fluidized bed. In the case of 600 ° C., partial decomposition of the heavy liquefied product occurred, and generation of H ₂ and CO ₂ was recognized.

Table 1 shows the composition and recovery rate of the separated and recovered solvent.
When the heating temperature of the porous particles is 500 ° C., the solvent recovery rate is 100
%, The solvent in the solution was 77%, and the heavy liquefaction was 23%. The recovery rate as heavy liquefied material was 30%. The recovery rate as a benzene-soluble component was 64%. These recovery rates are extremely high as compared with the recovery rates in the case of the conventional low-temperature distillation method (distillation method in which the distillation temperature is lowered to prevent the above-mentioned trouble).

When the heating temperature of the porous particles is 600 ° C, the solution recovery rate,
The solution composition was the same as that at 500 ° C., but the recovery as a heavy liquefied product was 28%, and the recovery as a benzene-soluble component was 60%, which was lower than at 500 ° C. This is due to the decomposition of the heavy liquefied material.

(Effect of the Invention) According to the coal liquefaction method of the present invention, when obtaining oil from an insoluble matter concentrated slurry obtained from a distillation residue, a high recovery rate can be obtained without causing operational troubles such as a conventional distillation method. The solution can be separated and recovered from the slurry, so that the liquefied oil yield can be improved, and the solvent can be recovered almost completely.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a process flow for separating and recovering a solvent from a slurry according to the first embodiment. (1) ... raw material storage tank, (2) ... booster blower, (3) ...
... high-speed fluidized bed, (4) ... cyclone, (5) ... condenser, (6) ... condensed oil receiver, (7) ... fluidized bed lower part,
(8) ... preheater, (9) ... pressure reducing valve.

──────────────────────────────────────────────────続 き Continuing on the front page (73) Patent holder 999999999 Cosmo Oil Co., Ltd. 1-1-1, Shibaura, Minato-ku, Tokyo (74) One of the above-mentioned sub-attorneys Patent Attorney Kan Akita (72) Inventor Osamu Okuma 1-272 Tamondai, Tarumizu-ku, Kobe, Hyogo (72) Inventor Tatsuo Hirano 3-3-20-605 Takashi, Takarazuka-shi, Hyogo No. 9 (72) Inventor Noriyuki Okuyama 2-3-1 Shinohara Auntoyamayamacho, Nada-ku, Kobe City, Hyogo Prefecture (72) Inventor Shinichi Nagae 2--10-6, Kita-Aoki, Higashinada-ku, Kobe City, Hyogo Prefecture Osamu Sato (56) References JP-A-61-163990 (JP, A) JP-A-62-127390 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10G 1/04, 1/06

Claims (5)

(57) [Claims] 1. A raw coal is hydrogenated, distilled and separated into an oil and a distillation residue, and the residue is subjected to a solvent demineralization treatment to separate an oil solution and an insoluble concentrated slurry. A coal liquefaction method for separating and recovering a solution from insolubles,
The slurry is sprayed on a high-speed fluidized bed using porous particles heated to 400 to 650 ° C., and the solvent in the slurry is evaporated and then condensed to be taken out as a liquid. A method for liquefying coal, comprising separating and recovering liquefied matter. 2. The method according to claim 1, wherein the porous particles of the fluidized bed are heated to 400 to 550 ° C. 3. The fluidized bed according to claim 1, wherein the porous particles have a particle size of 100 to 300.
2. The amorphous alumina or zeolite of .mu.m.
4. A method for liquefying coal as described in 1. above. 4. The coal liquefaction method according to claim 1, wherein the moving speed of the fluidized bed is 5 to 20 cm / sec. 5. The coal according to claim 1, wherein the slurry is concentrated under reduced pressure at a normal pressure or reduced pressure at a temperature of 300 ° C. or lower to remove insolubles in the slurry and then sprayed on the fluidized bed. Liquefaction method.