JPH0819418B2 - Liquefaction method of coal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for liquefying coal, and more particularly to a process for hydrogenating coal such as brown coal, a process for distilling a hydrogenated product, and a process for deashing a distillation residue. The present invention relates to a coal liquefaction method including a process.

(Prior Art) A typical hydrogenation method is a liquefaction method of coal. In this method, raw coal is pulverized and mixed with a slurrying solvent and a catalyst to form a slurry, which is then supplied to a primary hydrogenation tower for hydrogenation, and the hydrogenated product is distilled in a distillation tower to produce light oil. First, a primary hydrogenation method of separating into a medium oil and a distillation residue (containing ash and heavy oil as an oil component), and further deashing the distillation residue to reduce the ash content. There are a secondary hydrogenation method of secondary hydrogenation and distillation, and a multistage hydrogenation method of further hydrogenating and distilling the residue of the distillation. The primary hydrogenation catalyst is usually an iron-based catalyst, and the hydrogenation catalysts after the secondary hydrogenation are Ni-Mo-based or Co-
Mo-based catalyst is used.

The above-mentioned deashing treatment is often carried out by a solvent deashing treatment method. As shown in FIG. 2, this deashing treatment method involves mixing the distillation residue with a deashing solvent in a dissolution tank (1), In, the heavy substances in the distillation residue are dissolved to form a solution in which ash and insoluble heavy substances coexist, and the solution is continuously or intermittently supplied to the settling tank (2), and in the settling tank (2) The ash and insoluble heavy substances in the solution are allowed to settle, a slurry-like solution having a high ash concentration (ash concentrated slurry) is formed in the lower part of the settling tank (2), and a solution having a low ash concentration (ash diluted solution) is formed in the upper part thereof. Form, draw out the ash dilution liquid from the upper part of the sedimentation tank (2),
The ash concentrated slurry is extracted from the lower part of the settling tank (2).

The ash-concentrated slurry is fed to an oil evaporation separator through a slurry flow pipe connected to an outlet at the bottom of the settling tank (2) to evaporate the heavy oil and the solvent, and to remove the ash and insoluble heavy substances. It is separated and collected.

In such a deashing method, when the ash concentration of the ash-concentrated slurry in the lower part of the settling tank (2) is high and is about 30% or more, the ash in the slurry is adhered by a sticky heavy substance to form an agglomerate and settle. It adheres to the outlet of the lower part of the tank (2) and the inside of the slurry flow pipe, and is further clogged to cause clogging of the slurry flow pipe and the like. Further, when the ash concentration is low, it implies that the ash is not sufficiently settled in the settling tank (2), and a good ash diluted solution is not obtained. Therefore, the ash concentration target value (predetermined value) of the ash concentrated slurry in the lower part of the settling tank (2) is usually set to 10% or more.

In order to prevent the occurrence of problems such as the above clogging, measure the ash concentration of the ash-concentrated slurry at any time, and adjust the deashing conditions such as the amount of ash-concentrated slurry withdrawn and the temperature of the sedimentation tank according to the concentration. There is a need to. Therefore, it is extremely important to measure the ash concentration of the ash-concentrated slurry.

The ash concentration of the ash concentrated slurry in the lower part of the settling tank (2) is measured by a part of the ash concentrated slurry in the lower part of the settling tank (2) and by the ash analysis method of JIS M-8812.
That is, the method is carried out by placing the sampled slurry in a crucible, heating it to evaporate it to dryness, weighing the residue (residual ash), and determining the proportion of the sampled slurry.

(Problems to be solved by the invention) However, in the conventional coal liquefaction method, in measuring the ash concentration of the ash concentrated slurry in the lower part of the settling tank,
Since it takes a long time (approximately 4 hours) to evaporate and dry the collected slurry, it takes a long time (4 hours) to measure the ash concentration of the ash-concentrated slurry.
It takes more than time). Therefore, at the time when the ash concentration of the ash-concentrated slurry in the lower part of the settling tank (2) actually becomes lower than the predetermined value and the deashing process starts to become abnormal,
The abnormality cannot be grasped at that time at all, and can be recognized as a past thing after a long time has passed.

Therefore, adjustment of the deashing treatment conditions for recovering the ash concentration of the ash-concentrated slurry to the predetermined value cannot be made in time, and countermeasures against abnormal deashing treatment cannot be taken. Therefore, it is not possible to prevent the ash content in the slurry from being agglomerated and the slurry flow pipe from being clogged. In addition, it cannot be clarified whether or not an ash-concentrated slurry having a predetermined high ash concentration is obtained. As described above, there is a problem that the ash concentration useful as feed back information for adjusting deashing conditions such as the amount of ash concentrated slurry withdrawn cannot be measured.

The present invention has been made by paying attention to such a situation, and its object is to solve the above-mentioned problems of the conventional one, and to provide an ash-concentrated slurry at the bottom of the sedimentation tank during deashing treatment. A coal liquefaction method that can measure the ash concentration in a short time and is useful as information on the feed back for adjusting deashing conditions such as the amount of ash concentrated slurry extracted Is to provide.

(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, the coal liquefaction method according to the present invention is a hydrogenation step of hydrogenating coal in the presence of a catalyst and a solvent, a light oil by distilling the hydrogenated product, a medium oil, a heavy oil, and an ash content. A distillation step of separating into a distillation residue containing, and the distillation residue is mixed with a deashing solvent to dissolve a heavy substance to form a solution in which ash and an insoluble heavy substance coexist, and the solution is supplied to a sedimentation tank and settled. Liquefaction of coal including a deashing treatment step in which ash and insoluble heavy substances in the solution are settled in the tank, a solution with a low ash content is extracted from the upper part of the settling tank, and a slurry-like solution with a high ash content is extracted from the upper part of the settling tank. In the method, at the time of the decalcification treatment, γ-rays are irradiated toward the solution inside from the outside of the lower part of the settling tank, and the γ-ray dose that passes through the solution in the lower part of the settling tank and goes out to the outside is measured. Characterized in that the density of the solution is obtained, and the ash concentration of the solution is obtained from the density. This is a coal liquefaction method.

(Operation) As described above, the coal liquefaction method according to the present invention, when performing the deashing process, the γ from the outside of the lower part of the sedimentation tank toward the inside
The density of the solution is determined by irradiating a ray, and the γ-ray amount that passes through the solution in the lower part of the settling tank and goes out to the outside is determined, and the ash concentration of the solution is determined from the density.

The γ-dose (permeation γ-dose) that permeates the above solution, that is, the ash-concentrated slurry in the lower part of the settling tank and goes out, has a negative correlation with the density of the ash-concentrated slurry. The density of the slurry can be determined.

The density of the ash-concentrated slurry thus obtained corresponds to the proportion of ash in the slurry, that is, the ash concentration. Therefore, the ash concentration of the ash-concentrated slurry can be calculated by measuring the density of the ash-concentrated slurry.

As an instrument for irradiating γ-rays as described above and measuring the transmitted γ-ray dose to obtain the density, there is a so-called γ-ray density meter. Will be output.

Thus, the density measurement can be done instantly. Further, if the relationship between the ash concentration and the density of the ash concentrated slurry is obtained in advance, the ash concentration of the ash concentrated slurry can be quickly obtained from the density measurement value. Therefore, the ash concentration of the ash concentrated slurry can be measured in a very short time.

Further, the ash concentration of the ash-concentrated slurry can be accurately measured if the ash concentration is 5% or more, while the predetermined value of the ash concentration of the ash-concentrated slurry is usually 10% or more. There is no. That is, it is possible to confirm whether or not the ash concentration is a predetermined ash concentration, the ash concentration is lower than a predetermined value, and there is an abnormality in the deashing treatment. The accuracy is sufficient.

Therefore, it is possible to measure the ash concentration of the ash-concentrated slurry at the bottom of the settling tank during deashing in a very short time in real time.
Therefore, the ash concentration of the lower ash-concentrated slurry in the sedimentation tank, which is useful as feedback information for adjusting deashing conditions such as the amount of ash-concentrated slurry withdrawn, can be grasped at an early stage.

Therefore, whether or not the ash-concentrated slurry having a predetermined high ash concentration has been obtained can be quickly confirmed at any time.
In addition, when the ash concentration of the ash concentrated slurry in the lower part of the sedimentation tank is low and there is an abnormality in the deashing process, the abnormality can be detected at that time or immediately thereafter. Can be taken into account. For example, it becomes possible to take measures at an early stage such as reducing the amount of ash-concentrated slurry withdrawn, changing the conditions for dissolving heavy substances, and changing the temperature of the sedimentation tank.

Therefore, the ash concentration of the ash-concentrated slurry in the lower part of the settling tank can be easily maintained at a predetermined value, and as a result, troubles such as ash agglomeration, sticking in the pipe, and clogging in the pipe can be prevented.

The ash concentration measurement can be performed continuously and can be simplified without the need to collect an analytical sample solution. Furthermore, automatic measurement is possible.

(Example) The pulverized and dehydrated brown coal is pulverized and mixed with a slurrying solvent, an iron-based catalyst and a molten sulfur catalyst to form a slurry, which is then supplied to a hydrogenation tower for primary hydrogenation, and its hydrogenated product. Was distilled to obtain light oil, medium oil, and distillation residue.

The above-mentioned distillation residue was continuously deashed as follows. That is, after pulverizing the distillation residue, as shown in FIG.
Transfer to a dissolution tank (1), add a deashing solvent to dissolve heavy substances in the distillation residue, stir and mix at 250 ° C to form an ash coexisting solution, and continuously add the solution to the sedimentation tank (2). Ash and insoluble heavy substances are settled in the settling tank (2), an ash concentrated slurry is formed in the lower part of the settling tank (2), and an ash diluting liquid is formed in the upper part of the settling tank (2). The ash diluted liquid was extracted, and the ash concentrated slurry was extracted from the lower part of the sedimentation tank (2).

During the above deashing treatment, a settling tank (2) was used with a γ-ray density meter.
The lower ash concentrated slurry ash concentration was continuously determined. That is, from the outside of the lower part of the settling tank (2), γ-rays are irradiated to the ash-concentrated slurry in the lower part of the settling tank (2) by the γ-ray irradiation means (3), the transmitted γ-dose is counted, and the density is converted into the density. The density of the ash-concentrated slurry was measured by the displaying means (4), and the ash concentration of the ash-concentrating slurry was determined by the displaying means (5) by converting the density into the ash concentration. In addition, with respect to the above-mentioned means (4), calibration for making the transmitted γ dose correspond to the ash-concentrated slurry density is performed in advance,
For the means (5), the relationship between the density and the ash concentration of the ash-concentrated slurry obtained in advance was input and calibrated.

According to such measurement, the time required from γ-ray irradiation to ash concentration display is within 1 second, and the ash concentration can be continuously measured in real time. As a result, it was confirmed that the ash concentration of the ash concentrated slurry in the lower part of the settling tank (2) fluctuates from moment to moment.

Depending on the measured value of the ash concentration, the deashing treatment conditions were adjusted each time. That is, when the measured ash concentration was 10% or more, the deashing conditions were kept constant without adjustment, but when it was less than 10%, the amount of solution supplied to the settling tank (2) immediately after that. The amount of the ash diluted liquid withdrawn from the upper part of the settling tank (2) and the amount of the ash concentrated slurry withdrawn from the lower part of the settling tank (2), and then the mixing ratio of the distillation residue and the deashing solvent and the mixing temperature. Alternatively, the deashing conditions such as the temperature of the sedimentation tank (2) were adjusted to recover the ash concentration of the ash-concentrated slurry in the lower part of the sedimentation tank (2) to 10% or more.

In this way, it is possible to quickly confirm in real time whether the ash concentration of the ash-concentrated slurry in the lower part of the settling tank (2) has reached a predetermined value (10% or more). At some point, I was able to detect the anomaly at that time and take countermeasures early. As a result, the ash concentration of the ash-concentrated slurry could be maintained at a predetermined value at almost all times. Therefore, no trouble such as agglomeration of ash, adhesion to the inside of the pipe, and blockage in the pipe was observed. On the other hand, the ash diluted solution obtained from the upper part of the settling tank (2) had a low ash concentration (200 ppm) and was good.

(Effects of the Invention) According to the coal liquefaction method of the present invention, the ash concentration of the ash concentrated slurry at the bottom of the sedimentation tank during deashing can be measured in an extremely short time, and the ash concentration slurry withdrawal amount and the like can be removed. The ash concentration of the lower ash concentrated slurry in the settling tank, which is useful as feed back information for adjusting ash treatment conditions, can be grasped in real time at an early stage. Further, the above ash concentration measurement can be continuously performed, and it is not necessary to collect an analytical sample solution, which can be simplified. Furthermore, automatic measurement is possible.

Therefore, it becomes possible to always easily and quickly confirm whether or not the ash concentrated slurry having a predetermined high ash concentration is obtained. Also, when the ash concentration in the lower ash concentration slurry of the settling tank is low and abnormalities in deashing process are occurring, the abnormalities can be detected at that time, and therefore countermeasures against abnormalities in deashing process can be taken early. . Therefore, the ash concentration of the ash-concentrated slurry in the lower part of the settling tank can be easily maintained at a predetermined value, and as a result, troubles such as ash agglomeration, sticking in the pipe, and clogging in the pipe can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a flow chart for explaining the deashing process of the coal liquefaction method according to the embodiment of the present invention, and FIG. 2 is the solvent deashing of distillation residue in the coal liquefaction process by the hydrogenation liquefaction method. It is a schematic diagram of a flow chart for explaining a processing method. (1) …… Dissolution tank, (2) …… Settling tank, (3) …… γ-ray irradiation means (4) …… Means for measuring the transmitted γ-dose and displaying the density conversion (5) …… Density for ash concentration Means to convert and display

Claims (1)

[Claims] 1. A hydrogenation step of hydrogenating coal in the coexistence of a catalyst and a solvent, and distilling the hydrogenated product to separate light oil, medium oil, and distillation residue containing heavy substances and ash. Distillation step to, the distillation residue is mixed with a deashing solvent to dissolve heavy substances to form a solution in which ash coexists, and the solution is supplied to a sedimentation tank,
In a liquefaction method of coal including a deashing treatment step of precipitating ash content in the solution in the settling tank, extracting a solution having a low ash content from the upper part of the settling tank, and extracting a slurry-like solution having a high ash content from the lower part of the settling tank, At the time of the decalcification treatment, γ-rays are radiated toward the solution inside the lower part of the settling tank from the outside, and the γ-ray dose that passes through the solution in the lower part of the settling tank and goes out to the outside is measured. A method for liquefying coal, characterized in that the density is obtained and the ash concentration of the solution is obtained from the density.