JPH0354719B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for handling slurry fuel formed by mixing pulverized solid fuel such as coal with a liquid such as water.

Slurry fuel (hereinafter simply referred to as "slurry"), which is produced by pulverizing solid fuel such as coal and mixing this pulverized solid fuel with liquid such as water, allows solid fuel to be transported through pipes, and Recently, it has been attracting a lot of attention because it is easy to control combustion. However, the following problems have been pointed out, and improvements are desired. The following problems are explained, solid content is coal,
Taking slurry fuel with water as the liquid as an example, (1) Since the mixing ratio of coal and water was kept constant from the time the slurry was stored to the time it was combusted, there was no problem in at least one of the slurry storage or combustion stages. It was happening. That is, (a) When the concentration of coal is high, the viscosity becomes high, and although it is possible to prevent the coal from settling during storage, it causes clogging in the pipes, especially in the parts that receive heat.

(b) On the other hand, if the concentration of coal is low, the viscosity will be low and clogging in the pipes can be prevented, but on the other hand, the coal will settle and solidify during storage, resulting in so-called hard packs. For this reason, it is necessary to periodically remove the hard bag from the bottom of the storage tank.

(2) Due to the reason mentioned in (1), the concentration of the slurry is kept low to prevent solidification in the pipes, and a stabilizer is added to the slurry to prevent coal from settling during storage of this low concentration slurry. A method has also been proposed in which the compound is mixed in, but this method has the following problems.

(a) The price of the slurry itself increases because the stabilizer is expensive.

(b) Acetic acid, calcium chloride (CaCl ₂ ), etc. are used as stabilizers, but the components in the stabilizers may damage the combustion equipment, and especially when calcium chloride is used, severe Corrosion occurs.

(c) Incorporation of stabilizers also worsens the atomization characteristics of the slurry and reduces combustion efficiency.

An object of the present invention is to provide a slurry fuel handling method that can eliminate the problems of the prior art described above.

In short, this invention provides a method for storing coal-water slurry fuel and delivering the stored fuel to a combustion device, in which the viscosity is reduced during storage of the slurry fuel.
This slurry fuel handling method is characterized by maintaining the slurry fuel at 2000 CP or more and adding water to the slurry fuel to reduce the slurry fuel to 2000 CP or less when feeding the slurry fuel from the slurry fuel storage section to the combustion section.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the results of the inventors' measurements of the relationship between the coal concentration and the viscosity of slurry fuel in a mixed fuel of pulverized coal and water. As shown in the figure, the viscosity increases rapidly as the coal concentration increases, for example, when the concentration is 70%
In the case of
It was confirmed that the number increased by two times. The inventors conducted tests on slurry transportation and storage using slurries of different viscosities. As a result, it was confirmed that when transporting slurry, there is almost no clogging when the slurry is less than 2000 CP, and when the slurry is more than 2000 CP, there is almost no hard packing in the storage tank. . In other words, if we express this in terms of coal concentration, it means that if the concentration is below about 74%, it is suitable for transportation, and if the concentration is higher than that, it is suitable for storage.

FIG. 2 shows a first embodiment of a slurry fuel handling method constructed based on the tests described above. In the figure, coal 1 and water 2 are produced in a slurry manufacturing device 3 to form a highly concentrated slurry (for example, a coal concentration of 74%).
The above slurry becomes 4) and is stored in the storage means 5. In this case, as described above, the viscosity of the highly concentrated slurry 4 is maintained at approximately 2000 CP or more, so that hard packs due to coal settling and solidification do not occur.
The highly concentrated slurry 4 leaving the storage means 5 is transferred to the transportation means 6
and then reaches the storage means 7. Here, water 8 is supplied to reduce the concentration of the slurry, resulting in a low viscosity slurry 9 whose viscosity is reduced to 2000 CP or less. The low viscosity slurry 9 is atomized in a burner 10 and combusted in a combustion device 11 . burner 10
Since a low viscosity slurry is supplied to
The atomization characteristics of the slurry in the burner are improved and the combustion efficiency is increased, and the controllability of combustion is also improved because the flow rate is better controlled.

FIG. 3 shows a second embodiment. In this embodiment, the highly concentrated slurry 4 and water 8 are mixed downstream of the temporary storage means 7. In this embodiment, there is no need to provide a mixing and stirring device for the temporary storage means 7. However, since there is a risk of the slurry solidifying near the burner 10, it is desirable to mix it with water 8 as close to the temporary storage means 7 as possible to form a low-concentration slurry 9 as soon as possible.

FIG. 4 shows a third embodiment. In the case of this embodiment, a service tank 13 that specializes in mixing high concentration slurry 4 and water 8 is arranged between the temporary storage means and the burner 10 to reduce the concentration of the slurry and temporarily store it. The means 7 is intended to be used purely as a flow rate adjusting means.

In the above embodiments, a stabilizer may be added to the high concentration slurry as long as it does not deteriorate the atomization characteristics during combustion or cause corrosion to the combustion device.

By practicing this invention, no or only a small amount of stabilizers are used.
Solids such as coal do not settle or solidify during slurry storage.

Furthermore, since the viscosity of the slurry is low during slurry feeding and combustion, clogging in the piping does not occur, and the atomization characteristics of the slurry are improved, among other effects.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between coal concentration and viscosity of slurry fuel, Fig. 2 is a system diagram of slurry fuel handling showing the first embodiment of this invention, and Fig. 3 is a diagram showing the second embodiment. FIG. 4 is a system diagram showing the third embodiment. 4...High concentration slurry, 8...Water, 9...Low concentration slurry.

Claims (1)

[Claims] 1. A method for storing coal-water slurry fuel and feeding the stored fuel to a combustion device, wherein the viscosity is maintained at 2000 CP or more during storage of the slurry fuel,
A method for handling slurry fuel, characterized in that when the slurry fuel is fed from the slurry fuel storage section to the combustion section, water is added to the slurry fuel to reduce the concentration to 2000 CP or less. 2. Reduce the solid content concentration of slurry fuel to approximately 74% during storage.
The method for handling slurry fuel according to claim 1, characterized in that the solid content concentration during feeding is approximately 47% or less.