JPH0617942A - Ball valve of high-pressure slurry supply pump - Google Patents

Abstract

PURPOSE:To provide a ball valve of a high-pressure slurry supply pump, used in transferring slurry containing solid particles at high pressure, with such a structure that when the slurry is transferred solid rough particles are not retained in the ball valve. CONSTITUTION:In a ball valve of a pump for supplying high-pressure slurry 11, the clearance 13 between a ball 15 and a guide 12 is equal to or greater than the maximum grain size of solid particles contained in the slurry and the rate of the open area of the ball valve as determined by the size of the ball 15 and guide 12 is 45% or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal liquefaction process for promoting a liquefaction reaction of coal in the presence of hydrogen at high temperature and high pressure, for example, to liquefy a coal slurry containing a mixture of coal, a catalyst and a solvent. In order to prevent feed troubles of the high pressure slurry pump to be supplied to the tower, the present invention relates to the modification of the ball valve used for the high pressure slurry supply pump, etc.
It is broadly applicable to processes that include solid particles such as coal in a slurry and require the slurry to be transferred with a plunger type high pressure pump.

The case of a coal liquefaction process will be described below as a typical example.

[0003]

2. Description of the Related Art A coal liquefaction method in a coal liquefaction process is obtained by hydrocracking a slurry prepared by mixing coal, a catalyst and a solvent at a high temperature and a high pressure in the presence of a catalyst by hydrogenation. After depressurizing the liquid substance, it is separated and refined into liquefied oil such as light oil, medium oil and heavy oil.

Of the liquefied oil thus obtained, the heavy oil is subjected to hydrogenation reaction of the solvent by hydrogenation in a solvent hydrogenation reaction tower, and after depressurization, the obtained solvent is liquefied as a circulating solvent. It is returned to the reaction step and used for preparing a coal slurry.

Coal used in the liquefaction reaction usually has a yield of 80% or more of coal particles having a particle size of 150 μm or less in order to facilitate the reaction during the hydrocracking reaction in the liquefaction reaction step. Grind so that

[0006] Coal is crushed by using a crusher such as a rod mill, a ball mill, a vibration mill, and a disc mill. Even if any of these crushers is used, the yield of coal particles having a particle size of 150 μm or less can be obtained. It is difficult to make it 100%, and the pulverized coal also contains relatively coarse particles of 500 μm or more.

On the other hand, a plunger type pump is used as a high pressure slurry pump for sending coal slurry to a liquefaction reaction tower via a heater, and its flow rate is usually 1
It is about 100 to 110 kg / hr.

As shown in FIG. 2, the structure of this plunger type high-pressure slurry pump is such that a portion called a ball valve composed of a ball and a guide is connected in multiple stages. It flows through the gap between the ball and the guide and is supplied to the target device.

The above-mentioned relatively coarse particles (500 μm or more) are present in the coal slurry, and when these particles cannot pass through the gap between the ball and the guide and remain there, further coal particles are generated. They adhere and deposit one after another to form bridges.

As a result, defective operation of the ball valve occurs, making it impossible to supply the high-pressure slurry, and as a result, the plant has been shut down and the high-pressure slurry pump is often washed.

[0011]

DISCLOSURE OF THE INVENTION The present inventors have proposed to prevent such feed trouble of a slurry pump and to carry out a long-term continuous operation of a coal liquefaction plant in a stable state in order to carry out coarse coal particles in a slurry. Attempts were made to use a wire mesh such as a strainer or to apply vibration from the outside of the high-pressure slurry pump using an air hammering device.

However, none of the methods could eliminate the feed trouble of the high-pressure slurry pump.

Therefore, it was studied to fundamentally improve the structure of the ball valve so that the coarse particles of coal do not stay in the ball valve.

The present invention relates to a ball valve of a high-pressure slurry supply pump used when a slurry containing solid particles such as coal is transferred at high pressure so that solid coarse particles do not remain in the ball valve during the slurry transfer. It is intended to be a structure.

[0015]

As a result of intensive studies to improve the above problems, the inventors of the present invention have found that the ball valve of the ball valve can be formed according to the maximum particle size of the solid particles contained in the slurry. To increase the clearance between the ball and the guide, and to determine the open area ratio of the ball valve that is determined by the size of the ball and the guide, that is, the ball and guide at the opening excluding the cross section of the ball and the guide in the ball valve cross section. It was found that the above problems can be fundamentally solved by setting the area ratio for the included cross section to a certain value or more.

That is, the gist of the present invention is that in a ball valve of a high-pressure slurry supply pump, the clearance between the ball and the guide is not less than the maximum particle size of the solid particles contained in the slurry and the size of the ball and the guide. The ball valve of the high pressure slurry supply pump has an open area ratio of 45% or more determined by the ball valve.

The present invention is, for example, a plunger type slurry pump for supplying coal slurry obtained by finely pulverizing coal, adding a catalyst and a solvent to the coal, and slurrying the slurry under high pressure. When the particles pass through the ball valve, the ball valve and the guide are prevented from stagnation and clogging, which prevents the slurry feed trouble due to defective operation of the ball valve. It shows the optimum structure of the ball and the guide.

[0018]

The coal liquefaction process that has led to the present invention will be described below, and the contents of the present invention will be described in detail together with the operation.

FIG. 1 shows the flow of the coal liquefaction process.

The raw material coal is usually pulverized by the pulverizer 1 so that the yield of 150 μm or less is 80% or more in consideration of the properties of the coal slurry or the reactivity during the coal liquefaction reaction.

The crushed coal is mixed with the circulating solvent for coal liquefaction sent from the solvent hydrogenation reaction tower 8 in the slurry adjusting tank 2 to form a slurry.

The slurry concentration is usually adjusted within the range of about 1.0 to 3.0 (solvent / coal).

In order to increase the yield of liquefied oil, iron-based disposable catalysts (synthetic iron sulfide catalysts, natural iron ore catalysts) are mixed and used at the same time, and the addition amount is based on anhydrous, ashless base material coal. It is about 1 to 5%.

The coal slurry thus obtained is pressurized to 150 to 190 kg / cm ² by the high-pressure slurry pump 3 and then reacted with hydrogen gas in the liquefaction reaction tower 4 kept under high temperature and high pressure for a predetermined time to generate hydrogen. Chemically decompose.

The hydrocracking is carried out at a temperature of 430 to 470 ° C.
The pressure is 150 to 190 kg / cm ² and the liquefaction reaction of the raw coal proceeds by the decomposition reaction.

The product after the reaction is decomposed into gas, water and oil (liquefied oil) by the separator 5. Of the separated oils, light oil and medium oil are separated in the distillation facility 6 and are recovered as predetermined product oils.

The remaining heavy oil is vacuum-distilled in the vacuum distillation facility 7, and the one having a boiling point of 538 ° C. or higher is discharged outside the system as a liquefaction residue.

On the other hand, heavy oil having a boiling point fraction of less than 538 ° C. is kept at high temperature and high pressure and is reacted with hydrogen gas in a fixed bed solvent hydrogenation reaction tower 8 filled with a catalyst for a predetermined time. By carrying out a solvent hydrogenation reaction with the use of hydrogen, the hydrogen donating property is enhanced and the solvent is circulated to the slurry adjusting tank 2 as a circulating solvent.

Among these circulation systems, in the high-pressure slurry pump 3 for supplying to the liquefaction reaction tower 4, a relatively large particle (500 μm) among the fine coal particles present in the slurry is used.
High pressure slurry pump 3 due to
Due to the frequent occurrence of feed troubles that made it impossible to supply the coal slurry, the plant was shut down and oil was used for cleaning.

FIG. 2 is a diagram showing the overall structure of the high-pressure slurry pump. As shown in this figure, the coal slurry is sucked and compressed through the gap between the ball of the ball valve and the guide by the action of the plunger, and flows to the discharge side as a piston flow.

In the ball valve on the discharge side, when the slurry is compressed by the plunger, the balls move in the direction of the slurry flow, and when the slurry is sucked by the plunger, the ball moves in the direction of the slurry flow. Moves in the opposite direction.

FIG. 3 is a schematic diagram showing a side view of the ball valve in FIG. 2 when a slurry feed trouble occurs due to defective operation of the ball valve.

When coarse particles of coal are generated in the crushing process, the coarse particles are likely to stay in the gap between the ball and the guide of the high pressure slurry pump, which causes the fine particles in the slurry to adhere and deposit, and eventually. The ball does not move vertically.

As a result, the seal of the ball valve becomes incomplete, the slurry flows back to the suction side, and a feed trouble of the high-pressure slurry pump occurs.

In order to prevent the feed trouble of the high-pressure slurry pump generated by such a mechanism, the present inventors initially captured coarse coal particles existing in the slurry with a strainer of a wire mesh or a ball of the high-pressure slurry pump. An attempt was made to remove the coarse particles of coal deposited in the gap between the ball and the guide by the impact given to the valve part from outside by using an air hammer.

However, even with these methods, the feed trouble of the high-pressure slurry pump could not be improved.

The present inventors have made further detailed investigations,
By adjusting the ball valve open area ratio, which is determined by the size of the coarse particles of crushed coal, the clearance between the ball of the ball valve and the valve guide, and the size of the ball and the guide, We have found that it is possible to eliminate slurry feed troubles due to malfunctions, and have commercialized it.

Table 1 shows the particle size distribution of the finely pulverized coal used in the coal slurry.

The target of the particle size of this coal is to finely pulverize it so that 150 μm or less becomes 80% or more.

On the other hand, however, there are also relatively coarse particles of 150 μm or more, and nearly 2% of particles of 250 μm or more.

A commonly used crusher (rod mill,
(Ball mill, vibration mill, cage mill, disc mill, etc.)
To eliminate these relatively coarse particles, 1
It is extremely difficult to make the thickness 50 μm or less and 100%,
If they dare to do so, it will also significantly increase operating costs.

FIG. 4 shows an example of the dimensional relationship between the ball and the valve guide of a conventionally used ball valve.

In this conventional ball valve, the clearance between the ball and the valve guide is 0.3 mm, and when coal particles having a relatively coarse particle size of 250 μm or more as shown in Table 1 above exist, they pass through the gap. There is a possibility that you will not be able to do so and will stay there.

If there is a stagnation of coarse particles there, as a result, other coal particles are attached one after another with the particles as cores.
If they are deposited and a bridge is formed by coal particles, defective operation of the balls as shown in FIG. 3 will occur, leading to feed trouble of the high pressure slurry pump.

Therefore, as a first step of the modification, the present inventors reduced the thickness of the guide of the ball valve, and the clearance between the ball and the guide was changed from the conventional 0.3 mm to 0.6 m.
It was expanded to m and modified so that even the largest particle of coarse coal particles could pass through.

FIG. 5 shows the dimensional relationship between the modified ball and the valve guide.

By this modification, the number of occurrences of feed troubles in the high-pressure slurry pump was reduced to about half, but it was impossible to completely eliminate the number of troubles.

Therefore, the present inventors further studied, and as the second stage of modification, the width of the guide was reduced from 4 mm to 2 mm, and the open area ratio determined by the size of the ball and the guide was 45% or more. And As a result, it was found that the feed trouble of the high-pressure slurry pump due to coarse coal particles can be reduced to zero.

FIG. 6 shows the dimensional relationship between the modified ball and the valve guide.

As a reason why the feed trouble of the high-pressure slurry pump could not be completely eliminated by the modification to reduce the thickness of the guide shown in FIG.
If the opening area ratio determined by the size of the ball and the guide is small even if a clearance that allows coarse particles of m or more to pass is secured, coal particles with a relatively coarse particle size will be generated in the area between the ball and the guide. It is considered that the probability of attempting to pass through increased, and a bridge was formed with the coarse coal particles that happened to be unable to pass and stagnated as nuclei, causing ball malfunction.

As a means for increasing the open area ratio determined by the size of the ball and the guide, the thickness of this guide is further reduced by modifying the guide as shown in FIG. There is also a way to further increase the guide clearance.

However, in this method, the thickness of the guide is 1.
It must be 4 mm or less, which is not a good idea considering the wear caused by the coal slurry.

Therefore, as shown in FIG. 6, the width of the guide is set to 4 m of the conventional one.
By setting the thickness from m to 2 mm, the open area ratio could be set to 45% or more with the thickness of the guide that does not have to consider wear due to the coal slurry.

[0054]

EXAMPLES Next, the present invention will be described more specifically by way of examples.

The coal slurry prepared in the slurry adjusting tank 2 shown in FIG.
The pressure was increased to kg / cm ² , and this was sent to the liquefaction reaction tower 4.

When the 1T / D coal liquefaction plant was started to operate, feed troubles frequently occurred in the high-pressure slurry pump, and the plant was often shut down.

Therefore, as a first step, from FIG. 4 to FIG.
As a second step, from FIG. 5 to FIG. 6, as described above, the clearance between the ball and the guide of the ball valve was enlarged, the width of the guide was reduced, and the open area ratio of the ball valve was increased. Table 2 shows the history of the modification.

As a result, as shown in FIG. 7, the feed trouble of the high-pressure slurry pump was gradually reduced, and the feed trouble could be completely eliminated by carrying out the second stage modification (FIG. 6).

Thus, long-term continuous operation with the coal slurry can be stably performed without stopping the liquefaction plant, and the operating costs can be reduced.

[0060]

As described above, by modifying the ball valve of the high-pressure slurry pump according to the present invention, it becomes possible to eliminate the feed trouble of the slurry pump.

According to the present invention, not only the coal slurry but also solid particles contained in the slurry may stagnate between the ball of the ball valve and the guide to cause bridging, resulting in malfunction of the pump. To provide a ball valve for a high-pressure slurry supply pump applicable in the above process.

[0062]

[Table 1]

[0063]

[Table 2]

[Brief description of drawings]

FIG. 1 is an overall flow diagram of a coal liquefaction process that is an example of the present invention.

FIG. 2 is a structural diagram of a high-pressure slurry pump including a ball valve.

FIG. 3 is a schematic diagram when the ball valve is not operating properly.

FIG. 4 is a sectional view of a conventional ball valve.

FIG. 5 is a modified view (first stage) of the ball valve according to the present invention.

FIG. 6 is a modified view (second stage) of the ball valve according to the present invention.

FIG. 7 is a diagram showing changes in the occurrence status of feed trouble when a ball valve modified according to the present invention is used in a high-pressure slurry supply pump.

[Explanation of symbols]

 1 Crusher 2 Slurry adjusting tank 3 High pressure slurry pump 4 Liquefaction reaction tower 5 Separator 6 Distillation equipment 7 Vacuum distillation equipment 8 Solvent hydrogenation reaction tower 9 Ball valve 10 Plunger 11 Slurry 12 Guide 13 Clearance 14 Guide width 15 Ball 16 Coal Coarse particles a 4mm b 0.3mm c 4mm d 0.6mm e 2mm f 0.6mm

Front page continued (72) Inventor Kenji Kato 1 Kimitsu, Kimitsu-shi Kimitsu Works, Nippon Steel Corp. (72) Yoshiaki Doi, 1 Kimitsu, Kimitsu-shi Kimitsu Steel, Nippon Steel Corporation In-house (72) Inventor Hisataka Yamamoto 1-6-6 Totsukahigashi, Kawaguchi City, Saitama Prefecture (72) Kenji Iguchi 7-26-1 Makuhari Hongo, Chiba City, Chiba Prefecture

Claims (1)

[Claims] 1. A ball valve of a high-pressure slurry supply pump, wherein the clearance between the ball and the guide is equal to or larger than the maximum particle size of solid particles contained in the slurry, and the opening area of the ball valve is determined by the size of the ball and the guide. A ball valve for a high-pressure slurry supply pump, characterized in that the rate is 45% or more.