JPH0125878Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a combustion device, and particularly to a CWM (slurry-like mixture of pulverized coal and water or other liquid medium is abbreviated herein) combustion device. Regarding CWM combustion equipment that prevents clogging.

[Prior art]

As a coal combustion device, the average particle size is
It is known that pulverized coal that has been crushed to a size of about 50 microns is conveyed by air and continuously supplied into a furnace. This type of combustion apparatus has the drawbacks of increasing transportation costs because the coal is handled as a solid, and requiring a vast coal storage area. Furthermore, the problem of spontaneous combustion in coal storage areas,
Expenses were needed to deal with safety and environmental regulations, such as the issue of soot and dust scattering. Furthermore, unlike liquid fuel, it is difficult to automate the handling of this type of fuel, and it requires a large amount of manpower. Furthermore, with conventional techniques, it is difficult to measure flow rates, etc., and expensive measuring instruments are required. As described above, coal combustion according to the prior art is more expensive than gas or liquid fuels, and even if coal, which is advantageous in price, is used, the overall economic efficiency is low. In order to eliminate these drawbacks of the conventional technology, pulverized coal is mixed with a liquid medium such as water to form a slurry.
A technology has been developed that allows it to be handled in the same way as liquid fuel. This slurry-like mixture of pulverized coal and liquid medium is named CWM. Physically, CWM is simply a mixture of pulverized coal and a liquid medium such as water, so if the piping that transports CWM remains stationary for a long period of time, the pulverized coal will settle and some of it will dissolve. There is a problem that it becomes solid. Furthermore, water (liquid medium) controls the fluidity of CWM.
has a tendency to evaporate when heated, which is the CWM
This will promote solidification. That is, conventional
CWM combustion equipment has a problem in that clogging in the piping reduces the operational reliability of the combustion equipment.

[Purpose of invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, prevent clogging due to solidification in CWM piping, and obtain a safe and reliable CWM combustion device.

According to the present invention, a storage tank for storing CWM, a CWM supply pipe including a pump for pumping CWM,
A CWM combustion apparatus includes a burner gun connected to a CWM supply pipe, and at least one return pipe is provided, the return pipe including a classifier and a wet mill for re-grinding coarse CWM. provided.

According to the present invention, the above-mentioned drawbacks of the prior art are eliminated, and a CWM combustion device capable of highly efficient combustion and highly safe and reliable can be obtained.

It is possible to prevent deterioration of CWM quality and significantly improve the operational reliability of combustion equipment.

Further, according to the present invention, at least one purge device is connected to the CWM supply pipe, and the CWM in the supply pipe can be replaced by the purge fluid.
CWM combustion equipment is provided.

[Example of idea]

Hereinafter, preferred embodiments of the present invention will be described in detail as illustrated in the accompanying drawings to clarify the functions and effects of the present invention.

Figure 1 shows the basic structure of the CWM combustion device according to the present invention. CWM stored in a storage tank 1 is separated from coarse powder by a front strainer 2, pressurized by a pump 3, and further coarsened by a rear strainer 4. After the grain powder is separated and removed, it is supplied to a burner gun (not shown) via a CWM manifold 5 and a CWM supply branch pipe 6, and is burned. Drain pipes 7, 8, 910 are provided in the storage tank 1, front strainer 2, rear strainer 4, and manifold 5, respectively,
Each drain is connected to the storage tank 1 via a wet mill 11 and piping 12. Note that in FIG. 1, flow meters, valves, etc. are not shown. According to the apparatus shown in FIG. 1, coarse powder separated by a strainer,
The drained CWM is reformed by the wet mill 11 and returned to the storage tank.
CWM quality is maintained well. In addition, CWM
There is also concentrated water at the bottom and sides of storage tank 1.
CWM tends to occur easily, tank drain pipe 7
also has the function of discharging and reforming such concentrated CWM.

FIG. 2 shows an embodiment of the present invention, in which a classifier 13 is installed in the return pipe before the wet mill 11, and only coarse powder and solidified CWM are sent to the wet mill 11. The fine powder that has passed through the classifier 13 is combined with the fine powder CWM that has passed through the wet mill 11 and is returned to the storage tank 1. This arrangement is wet mill 1
It has the advantage of having a small capacity of 1 and preventing clogging of pipes.

In CWM, the viscosity characteristics change depending on the fine powder of about 10 μm or less, and the more fine powder there is, the better the quality. By re-grinding with a wet mill,
New bridges are created between CWM particles, making it difficult for CWM to settle. Note that in the wet mill 11, additives may be added to promote the formation of crosslinks between particles.

The present invention is applicable not only to CWM in which the medium fluid is water, but also to CWM including a medium fluid with low viscosity, such as methyl alcohol.

According to the present invention, it is possible to achieve a CWM utilization rate of nearly 100%. Note that even if CWM of poor quality is temporarily supplied to the storage tank 1, its quality can be improved. Furthermore, re-grinding improves the viscosity properties of CWM, which can improve combustion efficiency. In addition,
It is possible to prevent clogging of the CWM supply device, increasing safety and reliability.

FIG. 3 shows another embodiment of the invention, but the classifier and wet mill in the return line are omitted.
CWM supply system includes storage tank 1, pump 3,
Strainer 4, heater/header 5', branch piping 6,
A burner gun 15 is provided, and the CWM injected into the furnace 17 forms a flame 16 and burns.
As CWM return piping, a return piping 9 from the strainer 4, a piping 10 from the header 5', indicated by broken lines,
Return piping 1 from piping 6 or burner gun 15
0' is shown. These return pipes may be returned to the storage tank 1 separately as shown, but they may also be a common pipe as shown in FIG. 1 or 2, or a wet mill or classifier may be provided. In this embodiment, in addition to the above, a purge device is provided.
The purge device includes a purge fluid source 18, purge pipes 19, 20, 21, 22, and the like. Under normal operating conditions, the CWM is combusted by the burner gun 15 through the piping shown by the solid line. When the operation is stopped, it is heated in the heater/header 5'.
When CWM stops flowing, it tends to separate into an upper layer with a lot of water and a lower layer with a lot of pulverized coal, and the CWM concentration in the bottom layer increases and solidification occurs. Therefore, when the operation is stopped, it is necessary to stop the heating operation of the heater/header and return it to the CWM storage tank 1 via the return pipe 10 of the heater/header 5' as quickly as possible. Furthermore, in the case of the burner gun 15, it is susceptible to heat radiation from the furnace 17 and reaches a high temperature, so if CWM remains, it will solidify. Therefore, it is necessary to inject the CWM in the burner gun 15 into the furnace and replace it with purge fluid. For this purpose, purge fluid is supplied from the supply source 18 to the burner gun 15 via the piping 22. Note that water, air, _N2 gas, fuel oil, etc. are used as the purge fluid.

In order to prevent CWM from solidifying and clogging the CWM supply piping, a purge fluid supply piping is provided at a location where clogging tends to occur, and the purge fluid is returned to the storage tank 1 via a return piping. In the embodiment shown in FIG. 3, the pump 3 and strainer 4 are also provided with purge fluid supply piping 19, 20 and return piping 9. This arrangement is also effective as a countermeasure against failures of the pump 3 and strainer 4.

Figure 4 shows the relationship between CWM concentration and viscosity. This property varies somewhat depending on the particle size distribution of CWM due to differences in coal properties, additives, or manufacturing methods, but it is important to note that this property varies somewhat depending on the particle size distribution of CWM due to differences in coal properties, additives, or manufacturing methods.
Above), the viscosity tends to increase rapidly and solidification tends to occur. In the case of CWM combustion equipment, if the OWM concentration decreases, an excessive amount of water will be fed into the furnace, which inherently tends to increase latent heat loss due to water.
is desirable. However, if the concentration becomes too high, solidification will occur, so the concentration of CWM is limited to a fairly narrow range, and even a change in concentration of 4 to 5% will cause solidification.

The medium of the CWM (pulverized coal slurry) according to the present invention is not limited to water, but can also be applied to a pulverized coal slurry using a lower alcohol such as methyl alcohol as a medium. Lower alcohols vaporize more easily than water, and solidify the slurry more quickly. The present invention is particularly effective in such cases as well.

The invention is equally applicable to oil and pulverized coal slurries (commonly named COM). In the case of COM, the viscosity decreases when heated, and the area at the tip of the burner gun that receives heat radiation tends to become caulked, but the present invention is similarly applicable.

[Effect of idea]

According to the present invention, clogging in the piping can be effectively prevented and high safety and reliability can be obtained.
Furthermore, according to the present invention, even if clogging occurs, it is possible to return the CWM in the CWM piping before and after the clogging to the storage tank, and therefore maintenance and repair are easy. By returning the CWM in the piping to the storage tank, the utilization rate of pulverized coal can be increased and fuel can be saved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the basic structure of the CWM combustion device of the invention, Fig. 2 is a schematic system diagram showing an embodiment of the invention, and Fig. 3 shows another embodiment of the invention with some parts omitted. The schematic system diagram shown in FIG. 4 is a diagram illustrating the relationship between the concentration and viscosity of CWM. 1... Storage tank, 2... Front strainer, 3...
... Pump, 4 ... Rear strainer, 5 ... Manifold, 5' ... Heater and header, 6 ... CWM supply branch pipe, 7, 8, 9, 10, 10' ... Drain pipe,
11... Wet mill, 13... Separator, 15... Burner gun, 17... Furnace, 18... Purge fluid source, 19, 20, 21, 22... Purge fluid supply pipe.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) At least one system in a CWM combustion device including a storage tank for storing CWM, a CWM supply pipe including a pump for pumping CWM, and a burner gun connected to the CWM supply pipe. A return pipe is provided, and the return pipe connects the classifier and coarse particles.
A CWM combustion device comprising: a wet mill for re-grinding CWM; (2) The CWM combustion according to claim (1), characterized in that at least one system of purge equipment is connected to the CWM supply pipe, and the CWM in the supply pipe can be replaced by the purge fluid. Device. (3) Connect the purge fluid supply piping from the purge fluid source to the
3. The CWM combustion apparatus according to claim 2, wherein the CWM combustion apparatus is provided so as to be led to each element in the CWM supply piping, such as a pump and a strainer.