JPS6160788A - Solid fuel/water slurry - Google Patents

Abstract

PURPOSE:The title slurry with excellent stability, prepd. by mixing and dispersing a colloidal particle comprising a minute particle of coal, petroleum coke, clay mineral, a desulfurizing agent, etc. in a solid fuel/water slurry. CONSTITUTION:A solid fuel raw material A such as coal or petroleum coke sent to a bunker 3 by a conveyer 2 is roughtly crushed into about 7-mesh particles by a rough crusher 4, and the more than 90wt% thereof is supplied via a pipe line 5 to a tube mill 11 and not roll than 10wt% thereof is sent via a pipe line 6 to a stirred mill 9. On the other hand, water 16 and an additive 17 such as an anionic surfactant are supplied respectively via pipe lines 8 and 7 to the mills 9 and 11. A colloidal slurry wet milled in the stirred mill 9 and contg. a large amt. of minute particles is supplied via a pipe line 10 to the tube mill 11. A high-concn. solid fuel/water slurry obtd. by mixing in the mill 11 with the roughly crushed fuel, etc. previously supplied by means of wet milling is sent to a slurry tank 12 and then supplied via a pipe line 13 to a boiler plant or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a solid fuel-water slurry, and more particularly to the composition of the slurry.

[Electricity of invention]

Recently, coal has been increasingly used in place of petroleum, mainly in thermal power plants. However, solid fuels such as coal are difficult to handle, and transportation costs have a large impact on coal prices.

BACKGROUND ART There is active development of technology for turning coal into a slurry so that it can be handled as a fluid. Also.

Petroleum coke is used as a fuel for industrial boilers because it is cheap, and its fluidization technology is also attracting attention because it easily turns into slurry.

One of the coal fluidization technologies is COM (Coal and Oil Mixture), which is a mixture of heavy oil and coal.
There is e).

However, in the case of COM, the weight ratio of heavy oil and coal is approximately 1:1, so it cannot be said to be a completely petroleum-free fuel, and there is little merit in terms of price.Methacol, which is a mixture of methanol and coal, is also expensive. It is expensive and has not yet reached the practical stage.

On the other hand, CWM (Coa) is a mixture of coal and water.
L and L/Ajar Mix® is quite practical in terms of price and has been attracting attention recently.

To produce this CWM, a method is used in which water is added to one coal and wet pulverization is performed. However, if the proportion of water in the CWM is high, the thermal efficiency during combustion will decrease, and if the proportion of moisture is low, the viscosity of the CWM will increase, resulting in a large pressure loss during transportation. Furthermore, since CWM is composed of coal particles and water, there is a storage problem in that the coal particles settle and separate from the water after 9 hours.

In order to eliminate these drawbacks, attempts have been made to produce a slurry with high coal concentration, low viscosity, and good stability by adjusting the particle size distribution of coal particles and adding a dispersant. However, if the coal is highly hydrophobic, the cohesive force between the particles will be large, leading to storage problems such as poor stability.

In addition, 1 petroleum coke has very strong hydrophobicity and is produced by wet grinding of petroleum coke and water.
leu+w and l1ater Mixture)
It is also desired to develop a method to improve the stability of .

On the other hand, since CWM, especially PWM, has a high sulfur content, the concentration of sulfur oxides (SOx) produced by combustion increases.

It is also necessary to revise the method of reducing it.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and provide a highly stable solid fuel-water slurry.

[Outline of the invention]

To achieve the above object, the present invention is characterized in that by mixing colloidal particles in the slurry, the cohesive force between particles of solid fuel having strong hydrophobicity is weakened, and as a result, the stability of the slurry is improved. It is something to do.

In the present invention, coal, petroleum coke, viscosity, desulfurization agent, etc. are used as the colloid particles.

The viscosity mentioned above includes kaolin group and mica group such as sericite, and the desulfurization agent includes NaO in addition to calcium desulfurization agent.
H, Na: SO: +, Ni:! SOz.

NHJ OH, Mg(OH) 3, etc. can be applied.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The manufacturing process of solid a-water slurry according to the basic concept of the present invention is shown in FIG. 1. 2 in FIG. 1 is a conveyor.

3 is a bunker, 4 is a coarse grinder, 5 to 8 are pipes, 9 is a start mill, 10 is a pipe, 11 is a tube mill, 12 is a slurry tank, 13 is a slurry pipe, 14 is a distribution pipe, I5 is a classification Vessel, 16 is water! 7 is an additive (surfactant).

[lFA] of fuel such as coal or petroleum coke sent to bunker 3 by conveyor 2.

After being coarsely crushed to 7 meshes by the coarse crusher 4, the pipe j13
From 5.6, tube mill 11 and start mill 9, respectively.
(Robert H, Parry, Cacil H.

Chil Seon “Che＋＊1cal Engine
ers' )Isndbook″5jhed.

p8-29-30. NevYork, 1973) for wet milling. At this time, water 16 and additive (surfactant) 17 are supplied from pipes 7 and 8 into the respective mills 9 and 11. A colloidal slurry containing many fine particles wet-pulverized in the start mill 9 is supplied into the mill from the entrance side of the tube mill 11 through a pipe 10, wet-pulverized and mixed, and then passed through the pipe as a highly concentrated coal-water slurry. Sent out from 13.

It is supplied to a boiler device (not shown).

The start mill 9 is manufactured by UnionPro in the United States.
cess's attritor ("Chemica &!
Engineer's Handbook", 5
thed, p 8-29-30.

NevYork, 1973) and West Germany's Drai
There are permills manufactured by S Company, and tower mills (Tower Mill, written by Kawabata'g1M, Powder and Kogyosha, 1972), which provide the same effect as Start Mill 9, are also applicable.

In addition to this example, colloidal particles discharged from the start mill 9 can also be introduced from the outlet of the tube mill 11.

@2 Figure shows another example, in this case.

This example differs from the previous example in that the slurry from the start mill 9 and the slurry from the tube mill 11 are mixed in a tank 12.

In addition to this example, a part of the slurry discharged from the start mill 9 is supplied from the inlet side or the outlet side of the tube mill 1,
Another part can also be supplied to the tank 12.

Figure 3 shows yet another example, in which 1 fuel raw material A such as coal or petroleum coke is used in bunker 3.
It was put into the! It is pulverized by n-pulverization 8!4 and supplied to the tube mill 11. On the other hand, colloidal raw material B, which becomes colloidal particles, is put into a bunker 3a, is crushed by an i-pulverizer 4a, and then turned into a slurry containing colloidal particles by a start mill 9, and is supplied to a tube mill 11. Figure 4 shows yet another example; in this example,
After pulverizing fuel raw material A such as coal or petroleum coke with coarse pulverization fi4, a part of it is introduced into tube mill 11 to form colloidal particles, and then pulverization Ia4
It is supplied to the tube mill 9 together with the pulverized powder produced from the pulverized powder.

Figure 5 shows yet another example; in this example,
A fuel raw material A such as coal or petroleum coke and a colloidal raw material B that becomes colloidal particles are each processed in @I crusher 4.
, 4a, and then supplied to a tube mill 11 for pulverization and mixing. stop.

The slurry discharged from the tube mill 11 is sent to a classifier 15 such as a vibrating screen, and only the coarse particles separated by sieving are supplied to a start mill 9 to be pulverized into fine particles and then supplied to the tube mill 11 again. It has become.

FIG. 5 shows still another example. In this example, fuel raw material A such as 2 coal or petroleum coke is coarsely crushed in a coarse crusher 4 and then supplied to a tube mill 11, while colloidal particles The colloidal raw material B is processed by the coarse crusher 4a.
After being coarsely pulverized, the material is supplied to the tube mill 11, and while being pulverized, the coarsely pulverized colloidal raw material is further pulverized into fine particles to become a colloid, which is mixed in the slurry.

Figure 7 shows another example. In this example, 1
A fuel raw material A such as coal or petroleum coke is coarsely pulverized by a coarse pulverizer 4 and supplied to a tube mill 11, and the resulting slurry is led to a distributor 14 and a portion is put into a start mill 9 to remove particles in the slurry. The structure is such that it is turned into a colloid and then supplied to the tube mill 11 again.

Rather than coarsely pulverizing the raw material to become colloid particles and then feeding it directly to the start mill 9, as shown in Figs. It is possible to form a colloid more efficiently by supplying it to the mill 9.

A specific embodiment of the present invention will be described in detail below.

Example 1 Coal A (HGI: 3
6. 11.7% ash) and natural kaolin mineral B (H
GI is 80). The kaolin mineral B is wet-pulverized (solid concentration 50%, dry base) using a starter mill to form a colloid, and then the weight ratio of the kaolin mineral B is 10% or more of the total solid amount.

(preferably 10 to 15%) was supplied together with coal A from the inlet of the tube mill, and uniformly mixed and dispersed by the tube mill. However, 0.3% of anionic surfactant was added to Coal A in the tube mill.

The stability of the thus obtained coal-water slurry and a conventional coal-water slurry without the addition of colloid particles were compared and studied. In other words, each slurry was put into a cylinder with an inner diameter of 50 m+ and a height of 300 m.

Its stability was investigated by allowing it to stand still. One way to check stability is to place a slurry in a cylinder filled with slurry.
A glass rod with a length of 370 m and a diameter of 5 am was penetrated, and when the glass rod fell under its own weight and came to rest, the thickness of the hardback that settled and formed at the bottom of the cylinder was measured. The results are shown in Figure 8.

In each slurry, the amount of surfactant added was 0.3%, and the viscosity of the slurry was 800 to 1000 ep. In Figure 0, white circles are slurries without colloid particles, and black circles are slurries with colloid particles added.

As is clear from this figure, the conventional slurry without the addition of colloidal particles reached a hardback height of 16C11 after 01100 days, whereas the slurry according to the present invention had a hardback height of 16C11 even after 100 days of standing. It was found that the slurry was extremely stable with a diameter of 0.5 cm. Obtaining such a stable slurry expands the types of coal that can be produced as CWM and reduces troubles in storing and transporting the slurry.

Furthermore, the amount of colloidal particles added and the stability of CWM were investigated using the same method. FIG. 9 shows the influence on the stability of CWM when the weight ratio of colloidal particles supplied into the tube mill to the total solid amount was varied from 0 to 20%. In this test as well, the amount of surfactant added was 0.3% t', and the characteristics were shown after full lubrication. This figure shows that if the amount of colloidal particles added is 10% by weight or more, hardly any hardback is generated even after 100 days.

Example 2 Petroleum coke (HGI: 70, sulfur content: 5) was used instead of coal A.
．． 8%) and calcium-based desulfurization agent (8%) instead of kaolin mineral.
A coal-water slurry was produced in the same manner as in Example 1, using each of the coal-water slurries having an HGI of 75.

The stability of the product was measured in the same manner as in Example 1, and the results are shown in Figure 10. In Figure 1, the white circles are those without the addition of colloidal particles (calcium, nium-based desulfurization agent), and the black circles are As is clear from this figure, which shows the slurry containing colloidal particles (calculum desulfurization agent), the hardback height of the slurry of the present invention after 100 days of standing was 0.
3 am, whereas the conventional slurry had a hardback height of 23 am after 100 days of standing. Like this.

By adding colloidal particles, it was possible to improve the stability of PWM, which is easy to form into a slurry but generates hard back in a few hours.

Furthermore, the combustion characteristics of this PWM were studied. The concentration of sulfur oxides in flue gas was measured by sampling in the buried tunnel. The PWM of the present invention to which colloidal particles of a calcium-based desulfurization agent were added and the PWM produced by the conventional method (desulfurization agent addition amount: 0%) were burned, and the concentration of sulfur oxides contained in the flue gas was determined as follows: Shown below.

Petroleum coke has a higher sulfur content than coal.

When using petroleum coke, it is important to remove the sulfur content. By adding a colloidal desulfurizing agent to the slurry in an amount of 10% or more (preferably 10 to 15%) as in the present invention, the desulfurization rate can be increased. is 90% or more, which shows that the present invention is also effective in preventing environmental pollution.

Example 3 In the manufacturing process using only the tube mill shown in FIG. 6, petroleum coke A (HGI: 70, sulfur content: 5.
8%) to the mill per hour, I&ffi 2
Wet grinding (solid concentration 7) as 0 kg (45% of conventional method)
The stability of the PWM thus obtained was compared with the conventional one in the same manner as in Example 1.2. Compared to the conventional method, the stability of the PWM produced in this example was good, with the hardback height being 6f#' after 40 days of standing. This is thought to be due to the fact that by lowering the loading amount of petroleum coke, the residence time in the mill becomes longer and colloidal particles of 10 μm or less are produced. Colloidal particles are interposed between particles with strong cohesive force,
[Effect of the invention] With conventional methods, it was difficult to improve the stability of solid fuels, which are particularly hydrophobic and have a large cohesive force between particles. By adding rad particles, colloidal particles are interposed between solid twisted particles with strong coagulation force, weakening the cohesive force between particles and providing a highly stable solid fuel-water slurry. can.

[Brief explanation of the drawing]

Figures 1, 2, 3, 4, 5, 6 and 7 are flowcharts 1 and 8 explaining the manufacturing process of solid fuel-water slurry according to the present invention. 9 and 10 are characteristic diagrams of the stability of the slurry of the present invention and the conventional slurry.
The figure is a characteristic diagram showing the relationship between the amount of colloidal particles added and the stability of the slurry, and FIG. 11 is a characteristic diagram showing the relationship between the amount of desulfurizing agent added and the desulfurization rate. 4... Coarse crusher, 9... Start mill, 11... Tube mill, A... Coal or petroleum coke, B... Colloidal raw material. Figure 1 Figure 2 Figure 3 Figure 4 Figure wi S Figure 6 Figure w! J 7 Figure 8 Figure 9

Claims (8)

[Claims] (1) A solid fuel-water slurry characterized by mixing and dispersing colloidal particles. (2) In claim (1), the addition rate of the colloidal particles is about 10% by weight based on the total solid amount.
A solid fuel-water slurry characterized by the above. (3) The solid fuel-water slurry according to claim (1), wherein the solid fuel is coal. (4) The solid fuel-water slurry according to claim (1), wherein the solid fuel is petroleum coke. (5) The solid fuel-water slurry according to claim 1, wherein the colloidal particles are fine particles of coal. (6) A solid fuel-water slurry as set forth in claim (1), wherein the colloidal particles are fine particles of petroleum coke. (7) A solid fuel-water slurry according to claim (1), wherein the colloidal particles are fine particles of clay mineral. (8) The solid fuel-water slurry according to claim (1), wherein the colloidal particles are fine particles of a desulfurizing agent.