JPS6339985A - Cooled coarse grain separation apparatus of slurry - Google Patents

Abstract

PURPOSE:To stabilize the operation of a coarse grain remover through the prevention of coal particles and water from separating from each other in the coarse grain remover, by providing a closed cycle means for cooling a high-temp. coal-water slurry at the outlet of a pulverizer with a cooling medium comprising a low-temp. slurry on the downstream side of the coarse grain remover. CONSTITUTION:A cooled coarse grain separation apparatus of a slurry having the following structure. Coal 1, water 2 and an additive 17 are mixed and, at the same time, pulverized in a pulverizer 3 to prepare a coal-water slurry. Coarse grains contained in the slurry 4 are removed in a coarse grain remover 7 provided on the downstream side of the pulverizer 3, and the slurry 4 as a slurry product 8 is then fed into a storage tank 10. In the above-described process, a closed cycle means is provided to cool the high-temp. slurry 4 at the outlet of the pulverizer 3 with a cooling medium comprising a low-temp. slurry (fed through a transport pipe 12 from the storage tank 10) on the downstream side of the coarse grain remover 7 (by utilizing e.g., a heat exchanger 14).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling coarse particle separation device for slurry, particularly for coal-
The present invention relates to a cooling coarse particle separation device for a coal-water slurry suitable for stably and efficiently adjusting the particle size of coal particles in a water slurry to produce a coal-water slurry that does not pose a problem in transportation and combustion.

[Conventional technology]

Conventionally, an example of a coal-water slurry production-combustion system is shown in the fourth example.
In FIG. 4, coal 1, water 2, and a small amount of additive 17, which are fed into the pulverizer 3, are mixed and pulverized in the pulverizer 3 at the same time to form a coal-water slurry (CWM). The chemical slurry 4 enters the Banfa tank 5, passes through the coarse particle remover 7 by the chemical slurry pump 6, and is sent to the storage tank IO as a product slurry 8, and the separated coarse particle slurry 9 is returned to the crusher 3. and then re-ground. A combustion slurry 12 is supplied from the storage tank IO to a combustion burner 13 by a product slurry pump 1) and used as energy.

In the production of CWM using this method, each substance is supplied to the crusher 1) 13 at room temperature, but due to the change in thermal energy given to the crusher 3 as crushing power, the material is heated to 50 to 70°C at the outlet of the crusher 3. becomes a hot coal-water slurry.

[Problem that the invention seeks to solve]

In the conventional coal-water slurry production-combustion system described above, the crusher 3
This is a cooling system that does not require any operation on the downstream side. Therefore, the coal-water slurry at 50 to 70'C, which is approximately the same temperature as the CWM at the outlet of the crusher 3, enters the coarse particle remover 7 on the outlet side of the crusher 3. However, in the coarse particle remover 7, since the passage area of the sieve openings is not large relative to the coal particle diameter, the particles of the coal 1 are attracted to the coarse particle remover element 18 of the coarse particle remover 7, as shown in FIG. The fluidization of the slurry has a great effect on its ability to pass through the narrow passages between the cracks and prongs. In particular, when the temperature of the slurry is high, the viscosity of water, which is a medium for fluidizing coal particles, decreases, and only the water passes through the gaps in the coarse particle remover element 18 to pass between the particles of coal 1. The problem is that the slurry concentration as a product after passing through the coarse grain remover element 18 becomes low due to the remaining particles left behind, and the particles of coal 1 caught in the coarse grain remover element 18 lose fluidity and cause agglomeration inside. was there.

The purpose of the present invention is to solve the problems of the prior art described above,
It is possible to prevent separation of coal particles and water in the coarse grain remover, enable stable operation of the coarse grain remover, and keep the concentration of the product slurry taken out from the coarse grain remover within a predetermined range. The present invention relates to a cooling coarse particle separation device for coal-water slurry.

[Means for Solving the Problems] The above object is achieved by a closed cycle means for cooling the high-temperature slurry to be cooled at the outlet of the crusher using the low-temperature slurry inside the coarse particle remover as a cooling medium.

[Effect]

The temperature of the slurry introduced into the coarse particle remover can be maintained within a predetermined range. Therefore, the separation phenomenon between coal particles and water in the slurry is avoided, and the coal particles pass through the element in the coarse particle remover with water present on the surface, improving the passage rate of the slurry and This prevents the agglomeration of coal particles and stabilizes the operation of the coarse particle remover. The high-temperature slurry to be cooled is cooled and the slurry is heated again and introduced into a combustion device such as a burner.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 1 is a system diagram showing one embodiment of the present invention. 1st
In the figure, a heat exchanger 14 is installed in the middle of a coal-water slurry transport pipe that connects a buffer tank 5 and a coarse particle remover 7. Combustion slurry is supplied to the heat exchanger 14 from the storage tank IO via the combustion slurry transport pipe 12, and product slurry that has passed through the combustion slurry transport pipe 12 is supplied to the combustion burner 13. There is.

A bypass pipe 15 of the combustion slurry transport pipe 12 is provided to the heat exchanger 14, and a flow I1) regulating valve 16 is installed in the middle of the bypass pipe 15. This flow ttW regulating valve I6 is located downstream of the heat exchanger 14 and at the coarse particle remover 7.
It operates based on a signal from a temperature controller 20 installed upstream of the temperature controller 20. Further, a stirring 1) 19 is provided for applying a shearing force to the slurry in the coarse grain remover before passing through the coarse grain remover 18.

Note that the constituent parts in FIG. 1 other than those mentioned above are substantially the same as those in the conventional diagram shown in FIG.
Detailed explanation will be omitted.

Next, the operation of the coal-water slurry cooling coarse particle separation apparatus constructed as described above will be explained.

The slurry 4 at a high temperature of about 50 to 70°C from the crusher 3 is temporarily stored in a buffer tank 5 and then passed through a heat exchanger before being introduced into a coarse particle remover 7 via a raw slurry pump 6. It is cooled at L4.

The product slurry, which has a relatively low temperature due to atmospheric heat dissipation on the downstream side of the coarse particle remover 7, is supplied to the heat exchanger 14 via the combustion slurry transport pipe 12. A part of this product slurry is directly introduced into the combustion burner 13 via the bypass pipe 15 without being supplied to the heat exchanger 14 .

Therefore, the flow rate of the product slurry supplied to the heat exchanger 14 is determined by the flow rate 1Jf4 regulating valve 16 installed in the bypass pipe 15.
Controlled by adjusting the opening. The opening degree of the flow rate adjustment valve 16 is adjusted by measuring the temperature of the chemical slurry before it is introduced into the coarse particle remover 7 by the temperature controller 20, and adjusting the flow rate based on the deviation between this measured value and the set temperature value of the chemical slurry. An opening control signal is output to the regulating valve 16.

The slurry thus cooled to a predetermined temperature is introduced into the coarse particle remover 7. In the coarse particle remover 7, the viscosity of coal particles and water in the slurry is prevented from increasing excessively.

The agitator 19 installed in the coarse grain remover 7 applies shearing force to the slurry before it passes through the coarse grain remover element 18, which reduces the apparent viscosity of the slurry having thixotropic properties during passage. This is effective and improves the permeability and processing capacity of the coarse particle remover element 1B.

Means for applying shearing force to the slurry are not limited to the inside of the coarse particle remover; (1) providing a line mixer on the piping system; (2)
The same effect can be achieved by adopting measures such as providing an agitator in the buffer tank 5 or (3) selecting a pump that applies high shear in the slurry processing system.

The passage behavior of the CWM in the grit remover element 18 can be understood by the phenomena during flow of the slurry and its constituent coal/water. Figure 2 shows an example of the pseudoplastic flow characteristics of a non-diniton fluid as a general flow characteristic of CWM.
-4b is initial shear increase, b→C is constant shear, C-4d
shows the situation when the shear is reduced after that. This characteristic indicates a tendency for the viscosity to decrease over time at the same shear rate (thixotropic property), and in this kind of slurry, it takes as much time as possible before passing through the coarse particle remover element 1B. Applying shear to the slurry reduces its viscosity, allowing it to pass through the slurry more easily.

Next, Figure 3 shows the passage rate P of coal in the slurry with respect to temperature T.
If the temperature is low, the slurry may freeze or the viscosity of the slurry may be high.
If it is difficult for the slurry to pass through the coarse particle remover element 1B, and if the temperature is too high, the viscosity of the slurry will decrease, but the viscosity of water will also decrease at the same time, so only water will selectively pass through the coarse particle remover element 1B.
The passing rate is poor because the coal particles are left behind.In the end, there is an optimum temperature value where the passing rate is maximum in a certain range A, and the temperature of the slurry must be adjusted so that it falls within this range. This makes it possible to prevent water separation or coal particle aggregation within the coarse particle remover element 18.

This temperature range A varies depending on the type of slurry, etc., but in the case of coal-water slurry, it is 20 to 60 °C, preferably 30 to
The temperature is 50°C.

Further, the slurry at the outlet of the crusher 3 is cooled to a predetermined temperature range by the low-temperature slurry downstream of the coarse particle remover 7 on the downstream side of the crusher 3 and on the upstream side of the coarse particle remover 7. Cooling-
Adopts a heating self-closing cycle. Therefore, it is not necessary to use a cooling medium for slurry cooling from another equipment system, and in the heat exchanger 14, the slurry used for cooling the slurry at the outlet of the crusher 3 is Since it is heated again to almost the same temperature as the slurry and then supplied to the combustion burner 13, it is possible to improve the ignitability during combustion and the efficiency through heat recovery.

In the above-mentioned embodiments, the coarse particle separation and combustion burner systems in the CWM production facility were shown as systems in direct communication, but the present invention also provides
It can also be applied to systems whose purpose is to separate coarse particles in slurry. Further, the slurry is not limited to coal-water slurry, but can also be used for other solid-liquid mixtures.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to improve the processing capacity of the slurry when it passes through the element in the coarse particle remover, and to prevent the phenomenon of separation of solid particles and water and the phenomenon of agglomeration of solid particles.

Therefore, it is possible to improve the quality (t1 degree) of the product slurry and to stably operate the slurry manufacturing system.

[Brief explanation of drawings]

1st)! 1 is a system diagram showing an embodiment of the slurry cooling coarse particle separation device according to the present invention, FIG. 2 is a flow characteristic diagram of slurry, FIG. 3 is a correlation diagram showing element passage rate with respect to slurry temperature, and FIG. is a system diagram of conventional slurry manufacturing equipment, No. 5
The figure is an explanatory diagram showing a slurry passage situation in a cross section of an element in a slag remover. 3...Crusher, 5...Banpha tank, 7...Coarse particle remover, 10...Storage tank, 13... Combustion burner, 14...
・Heat exchanger, 15...Bypass pipe, 16...
... Flow rate adjustment valve, 18 ... Coarse particle remover element, 19 ... Stirrer, 20 ... Temperature controller. Agent Patent Attorney Masaru Nishimoto - Figure 1, Figure 2, Figure 3, Figure 3, T-

Claims (2)

[Claims] (1) A crusher that crushes and manufactures a mixture of solid and liquid;
This pulverizer is equipped with a coarse particle remover on the downstream side for separating and removing coarse particles in the slurry obtained by the pulverizer,
A slurry cooling coarse particle separation apparatus, characterized in that a closed cycle means is provided for cooling the high temperature slurry to be cooled at the outlet of the crusher using the low temperature slurry downstream of the coarse particle remover as a cooling medium. (2) A heat exchanger between the slurry to be cooled and a cooling medium, a cooling medium system that bypasses this heat exchanger, and means for adjusting the flow rate of the cooling medium to the heat exchanger side are provided. A cooling coarse particle separation device for slurry according to claim (1), (3) a means for applying shearing force to the slurry inside or on the upstream side of the coarse particle remover is provided. ) A cooling coarse particle separation device for slurry as described in item 2.