JPH0676584B2 - Liquefaction method of coal - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for liquefying coal, and more particularly, to a method for hydrogenating coal powder such as brown coal by a so-called two-stage hydrogenation method to obtain an oil component such as naphtha. A method for liquefying coal that effectively utilizes a distillation residue (R) obtained in a primary hydrogenation step, in particular, a solvent used for extracting a heavy liquefaction from a distillation residue (R) is used. The present invention relates to a liquefaction method of coal that is recovered without any problems.

(Prior Art) Conventionally, a coal liquefaction method has been a method in which a mixture containing raw coal, a catalyst and a solvent is first hydrogenated and then distilled to obtain naphtha (N), medium oil (M), ash, etc. Insoluble matter (hereinafter referred to as ash, etc.) and a distillation residue (R) containing heavy liquefaction,
A heavy liquefaction solution is extracted from the distillation residue (R) with a solvent to obtain a heavy liquefaction solution (C), and a slurry (S) containing ash and the like and a heavy liquefaction solution (Cs). While further separating and recovering the solvent from the slurry (S), the heavy liquefaction solution (C) is separated into a solvent and a heavy liquefaction, and the heavy liquefaction is converted to secondary water. It is added and distilled to obtain naphtha and medium oil.

The solvent extraction treatment of the above-mentioned distillation residue (R) is carried out by distillation residue (R)
A solvent is added to the solution to dissolve the heavy liquefaction in the distillation residue (R), and then the ash and the like are allowed to settle, and the slurry (S) in which the ash and the like are concentrated, and a supernatant liquid containing almost no ash and the like, That is, it is carried out by a method of separating into a heavy liquefaction solution (C).

Separation and recovery of the solvent from the slurry (S) and the heavy liquefaction solution (C) are performed by evaporating and vaporizing the solvent. The recovered solvent is reused as a solvent for addition in the solvent extraction process.

The intermediate oil obtained by the primary hydrogenation and the secondary hydrogenation is mixed as a raw material for the primary hydrogenation and finally converted into naphtha.

(Problems to be Solved by the Invention) By the way, when the slurry (S) obtained by the solvent extraction treatment is heated to evaporate and vaporize the solvent and separate and collect it, if the residue is only ash, it will flow. Since it has excellent properties and does not have adhesiveness, it can be easily collected.

However, in the conventional lime liquefaction method, since the slurry (S) obtained by the solvent extraction treatment is stably treated as the slurry (S), it contains a solution (Cs) in which heavy liquefaction is dissolved in addition to ash and the like. It is a waste. Usually, the ash content is 50 wt% or less, and in most cases 20 to 30 wt%, so the weight ratio of the dissolved heavy liquefaction and ash content is relatively high, and the weight ratio is about 1. It has become.

When this slurry (S) is heated to evaporate and vaporize the solvent and to separate and collect it, heavy liquefaction precipitates and remains with ash and the like. The deposited heavy liquefaction is in a softening and melting state at the temperature at which the solvent is vaporized and vaporized, and has a binder action, so that coexisting ash and the like are combined and integrated with ash and the like, and an adhesive substance with poor fluidity. Generate a large amount. As a result, this adhesive substance adheres to the inside of a device or container that heats the slurry (S) to evaporate and vaporize the solvent, and further inside a pipe for separation and recovery. Further, this deposit has the property of becoming a solid solid when the temperature is lowered, and its removal is extremely difficult. Therefore, the coal liquefaction plant cannot operate normally. The conventional coal liquefaction method has such a problem.

The present invention has been made in view of such circumstances, and the purpose is to solve the above-mentioned problems of the conventional one and to recover the solvent from the slurry (S) obtained by the solvent extraction treatment. Suppresses the generation of adhesive substances when
An object of the present invention is to provide a coal liquefaction method capable of preventing adherent substances from adhering to pipes and containers and ensuring normal operation of a coal liquefaction apparatus. Further, it is also an object of the present invention to improve the recovery rate of preasphaltene from the distillation residue (R).

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

That is, in the method described in the first claim, a mixture containing raw coal, a catalyst and a solvent is first hydrogenated and distilled to obtain naphtha (N), medium oil (M), ash, etc. At least a treatment of separating into a distillation residue (R) containing an insoluble matter and a heavy liquefaction, and extracting the heavy liquefaction from the distillation residue (R) by using a native naphtha having an average boiling point of 160 to 220 ° C. as a solvent. Performed once to obtain a heavy liquefaction solution (C) and a slurry (S) containing insoluble matter such as ash and a heavy liquefaction solution (Cs), and separating the solvent from the slurry (S). While recovering, the heavy liquefaction solution (C) is separated into a solvent and a heavy liquefaction,
In the liquefaction method of coal, wherein the heavy liquefact is secondarily hydrogenated and distilled to obtain naphtha and medium oil, the heavy liquefaction solution (Cs) in the slurry (S) obtained by the above solvent extraction treatment. The weight ratio of the heavy liquefied substance dissolved in to the insoluble matter such as ash is 0.
It is a coal liquefaction method characterized in that it is 3 or less.

(Operation) As described above, the coal liquefaction method according to the present invention,
Separates the solvent from the slurry (S) obtained by solvent extraction
When recovering, the weight ratio of the heavy liquefaction dissolved in the heavy liquid liquefaction solution (Cs) in this slurry (S) to the ash etc. (hereinafter referred to as the weight ratio A) is set to 0.3 or less. I am trying to do it. The reason for doing this is based on the findings obtained by various experimental investigations and studies on the influence of the weight ratio A. The details will be described below centering on the action of the weight ratio A.

That is, with respect to the above weight ratio A, when the weight ratio A becomes small, the amount of heavy liquefaction is reduced when the slurry (S) is heated to evaporate and vaporize the solvent and to separate and recover it. The weight ratio between the amount of precipitation and ash (hereinafter referred to as weight ratio B) becomes small. When the weight ratio B becomes small, the heavy liquefaction in the softened and molten state having the binder action causes
Although some ash and the like are combined, the diameter of the particles formed by engagement is small, and if the particle size is small, the adhesiveness is weak, and it is difficult for the particles to adhere to the device, piping or container. Further, even if the particle size becomes a little larger and the adhesive substance is generated, the amount of ash and the like bound is small, so that the amount of the adhesive substance generated is reduced and the amount of the adhesive substance is reduced.

The smaller the weight ratio A, the smaller the amount of the adherent substance generated, and the more the adhered amount. Regarding the quantitative influence of the weight ratio A, when the weight ratio A is set to 0.3 or less, the amount of the adhesive substance generated becomes extremely small with the decrease of the weight ratio A, and the adhesive substance in the pipe or the container is reduced. It is possible to achieve the purpose of preventing adherence of coal and ensure normal operation of the coal liquefaction device. The weight ratio A is 0.3
At this time, the amount of the adherent substance generated is not zero, but the adherent substance hardly adheres to the pipes and the container, and the coal liquefaction device can be operated more stably than in the conventional case. Further, when the weight ratio A is 0.15 or less, the amount of the adherent substance generated becomes zero, the adherent substance does not adhere to the pipes and the container at all, and the stability of the coal liquefaction device is extremely reliable. Become.
Therefore, the weight ratio A is set to 0.3 or less.

Here, the solvent extraction treatment, a solvent is added to the distillation residue, after dissolving the heavy liquefaction in the distillation residue, the ash etc. is allowed to settle, the slurry in which the ash etc. is concentrated, and the ash etc. A method of separating into a supernatant liquid containing almost no liquid, that is, a heavy liquefaction solution (hereinafter referred to as “one-time solvent extraction treatment”), and in most cases, the slurry coexists with the heavy liquefaction solution. , A method in which a solvent is added again to the slurry to separate it into a slurry in which insoluble matter is further concentrated and a supernatant (hereinafter, referred to as twice solvent extraction treatment), and a method in which this is repeated N times (hereinafter, , N times solvent extraction treatment).

In the present invention, this solvent extraction treatment is performed at least once. That is, any of the above-mentioned solvent extraction treatments can be applied and is not limited. It may be selected depending on the solvent extraction treatment conditions such as the solvent used and the desired value of the weight ratio A. However, when the condition and the value of A are the same, the amount of the solvent used in the two-time solvent extraction treatment is much smaller than that in the one-time solvent extraction treatment, which is excellent in economic efficiency. Further, the N times solvent extraction treatment (N is 3 or more) is superior, but its effect is gradually reduced.

With respect to the solvent used in the solvent extraction treatment, if autogenous naphtha having an average boiling point of 160 to 220 ° C. is used, most of the preasphaltene in the distillation residue can be dissolved in this solvent and recovered. Desirably 1 with an average boiling point of 160-180 ° C
It is recommended to use secondary hydrogenated naphtha or secondary hydrogenated naphtha, in which case 100% of the asphaltene in the distillation residue should be used.
% Will be recoverable.

Various methods can be used for separating and recovering the solvent from the slurry (S), but it is preferable to select it according to the kind of the solvent. In this respect, in the case of a solvent having a high evaporation temperature, a method of using a spray dryer, a gas stream dryer or a fluidized bed dryer, which can be operated at a relatively high temperature, is most suitable. If the solvent has a lower evaporation temperature than this case, it is better to use a vacuum dryer. Further, steam distillation has a drawback in that it can be used only in a limited number of cases, but it is a preferable method when it is subjected to N times solvent extraction treatment (N is 2 or more) and the solvent is toluene or the like. .

(Examples) Examples of the present invention will be described below.

First Example A mixture of crushed and dehydrated Victorian lignite, a catalyst and a solvent was subjected to primary hydrogenation under the conditions of a temperature of 430 to 460 ° C., a pressure of 10 to 20 MPa, and hydrogen pressure, and atmospheric distillation and vacuum distillation. It was separated into naphtha, medium oil and distillation residue (R), and the distillation residue (R) separated here was sent once to the step for solvent extraction treatment. As the catalyst, an iron / sulfur-based catalyst, an iron sulfide catalyst, etc. are used, and the distillation residue (R) has a boiling point of 420 ° C. or higher, pyridine-soluble matter 85%, pyridine-insoluble matter 15% (ash content 13%).
%) Is included.

That is, to the distillation residue (R), as a single solvent extraction treatment, 25 times the amount of primary hydrogenated naphtha having an average boiling point of 160 ° C. was added to 250 ° C. to dissolve the heavy liquefaction in the distillation residue. , Ash, etc. were settled and separated into a slurry (S) and a supernatant (C). The solubility of the pyridine-soluble substance in the distillation residue (R) at 250 ° C was about 96%. The separated slurry (S) has a ash concentration of 25% and a weight ratio A of 0.1.
It was 10.

This slurry (S) was steam distilled to separate and collect the solvent. As a result, the solvent could be separated and recovered without any problem, and the ash and the like could be easily recovered as powder. The steam distillation is performed by blowing steam into the slurry (S) to evaporate the solvent together with the steam, cooling the solvent to condense the steam, and separate the solvent. 90%.

In addition, the loss amount of the heavy liquefaction, which is an active ingredient, was 8% with respect to the amount of the distillation residue.

Second Example Solvent Separation from Slurry (S) in the First Example
Recovery was performed by a method using a spray dryer instead of steam distillation. As a result, like the first example, the solvent could be separated and recovered without any problem, and the ash and the like could be easily recovered as powder. The method using the spray dryer is performed by spraying the slurry (S) in a nitrogen stream at 250 ° C. to separate the solvent, and the solvent recovery rate here is 98 to 100%.

Third Example The solvent extraction treatment (one-time solvent extraction treatment) of the distillation residue (R) in the first example was performed twice.

That is, as the first solvent extraction treatment, 4 times the amount of primary hydrogenated naphtha having an average boiling point of 160 ° C. was added to the distillation residue (R),
After heating to 50 ° C and dissolving the heavy liquefaction in the distillation residue (R), the ash etc. is allowed to settle, and the slurry (S1) and the supernatant (C
1) and separated. The solubility of the pyridine-soluble matter in the distillation residue at 250 ° C was almost 100%. The slurry (S1) had an ash concentration of 25% and a weight ratio of heavy liquefaction to ash etc. of 0.53.

The above slurry (S1) has 3 times as the second solvent extraction treatment.
After adding twice the amount of toluene to 250 ° C. to dilute the heavy liquefaction solution, it was separated into a heavy liquefaction solution (C) and a slurry (S). The separated slurry (S) has a concentration of ash, etc. of 25%, and the weight ratio A of heavy liquefaction and ash, etc. is 0.
It was eleven.

This slurry (S) was steam-distilled in the same manner as in the first embodiment to separate and collect the solvent. As a result, no adherent substance was generated, and no adhesion phenomenon to the pipe or the container was observed. The solvent was also separated and recovered from the heavy liquefaction solution (C), and 100% of the used toluene was recovered.

On the other hand, the supernatant liquid (C1) is a heavy liquefied product obtained after the solvent is recovered, using a NiMo catalyst as a catalyst, at a temperature of 360 ° C. and a pressure of 15M.
Secondary hydrogenation was carried out under pressure of Pa and hydrogen, followed by distillation to obtain naphtha and medium oil.

As the solvent for the first solvent extraction treatment, the average boiling point was 16
The primary hydrogenated naphtha at 0 ° C was used for the distillation residue (R).
This is because 100% of the asphaltene is dissolved in this solvent and recovered.

Although toluene was used in the third embodiment as the solvent for the second solvent extraction treatment, the present invention is not limited to this, and the solubility is relatively high and the weight ratio A can be reduced, and the boiling point is low, so that the slurry (S) Any solvent can be used as long as it can be separated.
Desirably, a solvent having a low boiling point and / or a high solubility is used as compared with the solvent for the first solvent extraction treatment. For example, it is preferable to use toluene or primary hydrogenated naphtha.

The amount of the solvent used (the total amount of the primary hydrogenated naphtha and toluene) and the amount of the distillation residue (R) were 5.8 times, which were smaller than those in the first example. This indicates that applying the solvent extraction treatment twice is more economical.

The amount of heavy liquefaction, which is an active ingredient, was 1.2% with respect to the amount of distillation residue. This indicates that applying the solvent extraction treatment twice is advantageous in increasing the recovery rate of the heavy liquefaction.

Fourth Example Coal liquefaction and solvent recovery were performed in the same steps as in the third example, except for the amount of toluene added for the second solvent extraction treatment. That is, by changing the amount of toluene to be added, the weight ratio A of heavy liquefaction and ash etc. in the slurry (S) is
Was set to 0.01 to 0.53.

FIG. 1 shows the results obtained for the relationship between the weight ratio A and the amount of adhering substances generated when the slurry (S) was distilled by steam. Incidentally, it is when the particle size becomes extremely large that it actually adheres to the piping and the like among the particles formed by the heavy liquefied material and the ash and the like and causes a trouble. Therefore, the amount of the adhesive substance generated was measured by measuring the total weight of the particles having a particle size of 3.35 mm or more. Then, the percentage of the total weight of the heavy liquefaction material and the insoluble matter in the slurry (S) was determined, and the value was shown as the amount of the adhesive substance generated on the vertical axis of FIG. The horizontal axis of FIG. 1 is the weight ratio A.

As can be seen from FIG. 1, when the weight ratio A exceeds 0.3, the amount of adhering substances generated sharply increases. This weight ratio A is 0.3
If the amount is below, the amount of adherent substances generated is small, and if it is less than 0.15, no adhesion occurs. From this, it is most desirable that the weight ratio A is 0.15 or less in order to completely prevent the adhesion, but 0.3 or less is practically sufficient.

(Effect of the invention) According to the coal liquefaction method of the present invention, the generation of an adhesive substance when recovering the solvent from the slurry obtained by the solvent extraction treatment is suppressed, and the adhesive substance in the pipe or the container Since the adhesion can be prevented, the normal operation of the coal liquefaction device can be ensured.

Further, there is also an effect that most of the asphaltene in the distillation residue can be recovered.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the weight ratio A and the amount of adhesive substances generated when steam (S) is distilled by steam.
In FIG. 1, the horizontal axis represents the weight ratio A, while the vertical axis represents the amount of adhesive substances generated.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 999999999 Cosmo Oil Co., Ltd. 1-1-1, Shibaura, Minato-ku, Tokyo (72) Inventor Osamu Okuma 1-2-10, Tamondai, Tarumi-ku, Kobe-shi, Hyogo ) Inventor Shuichiro Sumida 9-6, 8-6, Chikushigaoka, Kita-ku, Kobe-shi, Hyogo Prefecture (72) Inventor Tatsuo Hirano 3-3-20-605 Takashi, Takarazuka-shi, Hyogo (72) Inventor Shigeo Tachibana Uozumi-cho, Akashi-shi, Hyogo Nakao 5 (72) Inventor Kaoru Masuda 7-3-5-513 Takamaru, Tarumi-ku, Kobe-shi, Hyogo (72) Inventor Shin-ichi Nagae 2-10-6 Kita-Aoki, Higashinada-ku, Kobe-shi, Hyogo (W6712 (72) Invention) Nobuyuki Okuyama 2-3-1 Nonomachi, Aunt Shinohara, Nada-ku, Kobe City, Hyogo Prefecture

Claims (1)

[Claims] 1. A mixture containing raw coal, a catalyst and a solvent,
Primary hydrogenated and distilled to separate into naphtha (N), medium oil (M), and distillation residue (R) containing insoluble matter such as ash and heavy liquefaction, and the distillation residue (R ) From the heavy liquefaction using an autogenous naphtha having an average boiling point of 160 to 220 ° C. as a solvent at least once, and the heavy liquefaction solution (C) and insoluble components such as ash and heavy liquefaction. Material solution (Cs)
And a slurry (S) containing, and separating and recovering the solvent from the slurry (S), while the heavy liquefaction solution (C) is obtained.
Is separated into a solvent and a heavy liquefaction, the heavy liquefaction is subjected to secondary hydrogenation, and distilled to obtain naphtha and medium oil. In the method of liquefying coal, the slurry ( S)
A method for liquefying coal, wherein the weight ratio of the heavy liquefaction dissolved in the heavy liquefaction solution (Cs) and the insoluble matter such as ash is 0.3 or less.