JPH07268367A - Production of paste composed of coal and water and apparatus therefor - Google Patents

Abstract

PURPOSE:To provide a production process for coal paste which is composed of coal and water and can be continuously fed because of its stabilized properties, and the apparatus for production thereof. CONSTITUTION:Moisture meter 14 continuously detects the moisture in the coal in a metering feeder 13. A weighing machine 15 continuously detects the weight of the coal in the metering feeder 13. Controller 16 adjusts the opening of a water-feeding valve 17 attached to a kneader 19 based on the inputted signals from the moisture meter 14 and the weighting machine 15 so that the water feed is controlled to keep the weight ratio of coal to water constant in the paste.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention burns a solid fuel such as coal in a pressurized fluidized bed, drives a steam turbine by the generated steam, and further drives a gas turbine by high-pressure and high-temperature combustion gas to raise the temperature. The present invention relates to a combustion furnace of a pressurized fluidized bed boiler combined cycle power plant that efficiently obtains electric power, and more particularly to a method and an apparatus for producing a paste made of a mixture of coal and water supplied to the combustion furnace.

[0002]

2. Description of the Related Art A pressurized fluidized bed boiler as described above can generate energy with high efficiency because it can obtain energy from steam and high-pressure combustion gas. However,
One of the challenges is to continuously and stably supply solid coal particles into a pressurized combustion furnace. Conventionally, as a method of supplying coal to a fluidized bed combustion furnace, coal particles and water are mixed to form a paste-like fluid (hereinafter simply referred to as “paste”), and the paste is pressurized and pumped by a spray nozzle. There is a wet supply system (for example, the invention described in JP-A No. 62-155433). The paste supply method does not require pretreatment such as drying and is low in cost, as compared with a dry supply method, for example, a method in which the pressure is increased by a lock hopper and then pneumatic transportation is performed.

[0003]

However, in the above-mentioned conventional paste supply method, it is important to minimize the amount of water added to coal in order to maintain the power generation efficiency at a high level. However, since the paste has a high viscosity and a chemical agent for dispersing coal particles is not added in order to reduce the production cost, the fluidity becomes extremely poor.

Further, since the paste has a maximum diameter of 4 to 10 mm and a weight average diameter of 1 to 2 mm and has a high viscosity, a particle size constitution containing a considerable amount of fine particles is required to obtain a paste having a low water content. That is, the coal particles in the paste are characterized in that they exist in a wide range of particle diameters from fine particles of several tens of μm to coarse particles of maximum 10 mm.

In order to produce a stable paste under the above constraints, the viscosity of the paste is 5 Pas to 20 Pa.
It is desirable to adjust to the range of s. When the viscosity of the paste is 20 Pas or more, the paste is clogged and dehydrated at the suction port of the pump, which causes a problem that the pump cannot be transported. On the other hand, when the viscosity of the paste is as low as 5 Pas, there is a problem that coarse particles settle and block in the pipe. The viscosity of the paste is mainly correlated with the coal concentration in the paste. That is, when the coal concentration is high, the viscosity of the paste increases, and conversely, when the coal concentration is low, the viscosity decreases. Therefore, the method of controlling the coal concentration in the paste is the most effective method for adjusting the viscosity of the paste. From such a viewpoint, it is necessary to accurately control the coal concentration of the paste.

However, in the conventional paste manufacturing method,
As in the invention disclosed in Japanese Patent Application Laid-Open No. 62-155433, the water content in the raw coal is not controlled, so that there is a problem that the coal concentration in the paste, that is, the viscosity is large.

As described above, the conventional paste manufacturing method has a problem in that the amount of water contained in the raw coal and the crushed coal varies, and a stable paste having good fluidity cannot be manufactured.

[0008] Therefore, an object of the present invention is to provide a method and an apparatus for producing a paste composed of coal and water, which can continuously supply a paste having stable properties.

[0009]

A paste production apparatus comprising coal and water according to the present invention comprises a raw coal supply device, a raw coal pulverizer, and pulverized coal pulverized by the pulverizer is mixed with water. In a device for producing a paste consisting of coal and water having a kneading device, means for continuously detecting the water content and weight of crushed coal, and water supply with the goal that the weight ratio of coal and water in the paste is constant. And means for adjusting the amount.

The apparatus for producing a paste of coal and water according to the present invention comprises a raw coal supply device, a raw coal crusher, and a kneading device for mixing the crushed carbon crushed by the crusher with water. In a paste manufacturing apparatus comprising coal and water,
It is preferable to have means for continuously detecting the water content and weight of the crushed coal, and means for adjusting the water supply amount and the crushed coal flow rate with the goal of keeping the weight ratio of the coal and water in the paste constant.

Further, the apparatus for producing a paste composed of coal and water of the present invention is provided with a mixer for mixing pulverized coal and coarse coal in a dry process before the step of measuring the water content and the weight of the pulverized coal. preferable.

Further, the apparatus for producing a paste of coal and water according to the present invention preferably uses at least one of a microwave type moisture meter and an infrared type moisture meter for measuring the moisture content of crushed coal.

On the other hand, the method for producing a paste of coal and water according to the present invention comprises a raw coal supply device, a raw coal pulverizer, and a kneading device for mixing the pulverized coal pulverized by the pulverizer with water. In the method for producing a paste consisting of coal and water used,
It is characterized in that the water content and the weight of the crushed coal are continuously detected, and the water supply amount is adjusted with the goal of keeping the weight ratio of the coal and water in the paste constant.

The method for producing a paste of coal and water according to the present invention comprises a raw coal supply device, a raw coal crusher, and a kneading device for mixing the crushed carbon crushed by the crusher with water. In the method for producing a paste consisting of coal and water,
It is preferable to continuously detect the water content and weight of the crushed coal and adjust the water supply amount and the crushed coal flow rate with the goal of keeping the weight ratio of the coal and water in the paste constant.

Further, in the method for producing a paste composed of coal and water of the present invention, it is preferable to provide a step of mixing pulverized coal and coarse coal in a dry process before the step of measuring the water content and the weight of pulverized coal. .

Further, in the method for producing a paste of coal and water according to the present invention, it is preferable to use at least one of a microwave type moisture meter and an infrared type moisture meter for measuring the moisture content of crushed coal.

[0017]

The present inventors have conducted extensive studies on a method for producing a paste composed of coal and water in a pressurized fluidized bed, and as a result, in order to produce the paste having stable fluidity, the ratio of coal to water is required. It was experimentally found that it is important to keep constant. Here, it has become clear that the fluctuation of water content in coal is actually 3 to 14%, which is larger than expected. When converted to the coal concentration in the paste, a fluctuation of 20% or more will occur.

The water content of the paste is generally 20 to 30%. However, the water content of raw coal varies within the range of 3 to 14%. Further, the weight measurement of raw coal in the step of producing the paste is performed in a state of containing water. Therefore, by measuring the amount of water contained in coal, the amount of coal and the amount of water supply can be controlled at the same time, and the concentration of coal in the paste can be controlled.

Thus, in the method and apparatus for producing a paste of coal and water of the present invention, the amount of water contained in the paste is continuously detected by continuously detecting the water content and weight of raw coal and crushed coal. Since the amount of water supply is adjusted so that the temperature is always constant, the paste having stable properties can be continuously supplied.

[0020]

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

FIG. 1 is a system diagram showing an apparatus for producing a paste composed of coal and water according to an embodiment of the present invention. First,
The main configuration of this device will be described. The raw coal bunker 1, the quantitative feeders 2, 3, the vibrating screen 4 and the screen 5 form a supply device of the raw coal A. The coarse crusher 6 is a crusher for crushing the raw coal A into the coarse coal B, and the fine crusher 8 is a crusher for crushing the raw coal A into the fine coal C.
Further, the mixer 12, the quantitative feeder 13, and the kneader 19
Is coarse coal B crushed by the coarse crusher 6 or the fine crusher 8.
And a kneading device for mixing pulverized coal C and water D.

The water content meter 14 continuously detects the water content in the coal in the fixed quantity feeder 13, and the weighing machine 15 continuously detects the weight of the coal in the fixed quantity feeder 13. Furthermore,
The controller 16 uses the moisture meter 1 input by the controller 23.
4 and the signal from the measuring device 15, based on the kneading device 19
The opening degree of the water supply valve 17 installed at is adjusted so that the weight ratio of the coal and the water in the paste is constant.

Next, the detailed configuration and operation of this embodiment will be described. The raw coal A in the raw coal bunker 1 is supplied to a vibrating screen 4 by a fixed-quantity feeder 2. Vibration sieve 4
A screen 5 is installed on the screen, and the raw coal A on the screen 5 is
Is crushed by the coarse crusher 6 and returned to the vibrating screen 4 again. Coarse coal B passed through screen 5 with vibrating screen 4
Are transferred to the distributor 12 by the conveyor 7. On the other hand, the raw coal bunker 1 is further provided with a quantitative feeder 3, and the raw coal A cut out by the quantitative feeder 3 is pulverized by a fine crusher 8
Is pulverized to produce pulverized coal C.

The pulverized coal C is transferred to the mixer 12 by the conveyor 7 simultaneously with the pulverized coal B produced by the coarse pulverizer 6. The pulverized coal C and the pulverized coal B, which are stirred and mixed by the mixer 12, are transferred to the quantitative feeder 13 again. The metering feeder 13 is provided with a moisture meter 14 and a coal meter 15,
The moisture in the coal and the weight of the coal in the quantitative feeder 13 are continuously detected.

The signal of the moisture meter 14 is sent to the control device 23 together with the signal of the measuring instrument 15. A signal from the control device 23 is connected to the controller 16 that adjusts the opening degree of the water supply valve 17 installed in the kneader 19. In the kneader 19, pulverized coal C and coarse coal B which are coal cut out by the quantitative feeder 13, water D supplied from the water supply valve 17 and limestone E cut out by the limestone feeder 26 are charged.
Stirring and mixing produce a paste consisting of coal and water. The paste produced by the kneader 19 is temporarily stored in the storage tank 21.

The moisture meter 14 installed in the quantitative feeder 13 is preferably a non-contact type far infrared ray type or microwave type. Further, as the coal measuring device 15, a measuring device using a general strain gauge is used.

On the other hand, one of the features of this embodiment is that a pulverized coal and coarse coal mixer 12 is installed in front of the quantitative feeder 13 in order to improve the accuracy of the infrared or microwave moisture meter. There is. When the particle size and bulk density of coal change, the reliability of the moisture meter decreases significantly. When measuring the water content with an infrared moisture meter, measure the water content of the coal only on the surface of the quantitative feeder. Therefore, when the particle size of coal is different, the water film thickness on the surface of the coal particles changes, which causes malfunction of the moisture meter. On the other hand, the measured value of water content by a microwave moisture meter is affected by the bulk density of coal. When the bulk density is large, the water content value is large, and when the bulk density is small, the water content value is small.

Therefore, it is important for the quantitative feeder to improve the accuracy of the moisture meter that the particle size distribution and bulk density of coal are uniform. Therefore, by installing the pulverized coal and coarse coal mixer 12 in front of the quantitative feeder 13, the particle size distribution and bulk density of the coal can be made uniform. That is, the accuracy of the moisture meter can be improved by installing the mixer 12.

Next, a method of controlling the amount of water supplied to the kneader 19 will be described. First, the water content in the coal and the flow rate of the coal are detected from the signals of the coal weighing device 15 and the moisture meter 14, respectively. In general, the optimum coal concentration is determined depending on the type of coal. On the other hand, since the coal concentration in the paste is represented by coal / (coal + water supply + water contained in coal), the amount of water supply for making the coal concentration constant can be determined from this. When limestone is used, limestone is regarded as a solid like coal, and the coal concentration can be defined by (coal + limestone) / (coal + limestone + water supply + water contained in coal). Also in the above case, the limestone E is the limestone feeder 2
The required water supply can be easily calculated because it is measured in 6.

As a result, the apparatus for producing a paste of coal and water according to this embodiment continuously detects the water content and weight of raw coal and crushed coal, and keeps the amount of water contained in the paste constant. Since the amount of water supply and the amount of coal can be adjusted so that a stable paste having a constant coal concentration and viscosity can be supplied, and as a result, the clogging of the paste transport pipe is eliminated and reliability is improved. Some pressurized fluidized bed boilers can also be provided.

[0031]

As described above, according to the present invention, the amount of water supplied can be adjusted so that the weight ratio of coal and water in the paste composed of coal and water is constant. It is possible to provide a method and an apparatus for manufacturing the paste, which can supply the stable and stable paste.

[Brief description of drawings]

FIG. 1 is a system diagram showing an apparatus for producing a paste composed of coal and water according to an embodiment of the present invention.

[Explanation of symbols]

 1 Raw coal bunker 2 Quantitative feeder 3 Quantitative feeder 4 Vibrating screen 5 Screen 6 Coarse crusher 7 Conveyor 8 Fine crusher 9 Meter 10 Meter 11 Control device 12 Mixer 13 Quantitative feeder 14 Moisture meter 15 Meter 16 controller 17 Water supply valve 18 Flowmeter 19 Kneader 20 Limestone bunker 21 Storage tank 22 Limestone feeder 23 Controller 24 Stirrer A Raw coal B Coarse coal C Fine coal D Water E Limestone F Paste

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Uemura 6-9 Takaracho, Kure-shi, Hiroshima Babcock Hitachi Kure Factory (72) Inventor Kodai Nonaka 6-9 Takaracho, Kure-shi, Hiroshima Babcock Hitachi Stock Company Kure Factory

Claims (8)

[Claims] 1. An apparatus for producing a paste composed of coal and water, comprising a raw coal supply device, a raw coal pulverizer, and a kneading device for mixing pulverized coal pulverized by the pulverizer with water.
Coal and water characterized by having means for continuously detecting the water content and weight of the crushed coal, and means for adjusting the water supply amount with the goal that the weight ratio of the coal and water in the paste is constant. Paste manufacturing equipment. 2. An apparatus for producing a paste composed of coal and water, comprising a raw coal supply device, a raw coal pulverizer, and a kneading device for mixing pulverized coal pulverized by the pulverizer with water.
Characterized in that it has means for continuously detecting the water content and weight of the crushed coal, and means for adjusting the water supply amount and the crushed coal flow rate with the goal that the weight ratio of the coal and water in the paste is constant. An apparatus for producing a paste composed of coal and water. 3. The apparatus for producing a paste composed of coal and water according to claim 1 or 2, wherein the pulverized coal and the pulverized coal are mixed in a dry state before the step of measuring the water content and the weight of the pulverized coal. An apparatus for producing a paste composed of coal and water, characterized by being provided with. 4. The apparatus for producing a paste composed of coal and water according to claim 1, 2 or 3, wherein at least one of a microwave moisture meter and an infrared moisture meter is used to measure the moisture content of the crushed coal. An apparatus for producing a paste composed of coal and water, characterized by using. 5. A method for producing a paste composed of coal and water using a raw coal supply device, a raw coal pulverizer, and a kneading device for mixing pulverized coal pulverized by the pulverizer with water,
Manufacture of a paste composed of coal and water, which is characterized by continuously detecting the water content and weight of crushed coal and adjusting the water supply amount with the goal that the weight ratio of coal and water in the paste is constant. Method. 6. A method for producing a paste composed of coal and water, comprising a raw coal supply device, a raw coal crusher, and a kneading device for mixing crushed carbon crushed by the crusher with water.
From the coal and water characterized by continuously detecting the water content and weight of the crushed coal and adjusting the feed water amount and the crushed coal flow rate with the goal that the weight ratio of the coal and water in the paste will be constant. Of making paste. 7. The method for producing a paste composed of coal and water according to claim 5 or 6, wherein a step of mixing pulverized coal and coarse coal in a dry process is performed before the step of measuring the water content and weight of the pulverized coal. A method for producing a paste composed of coal and water, which is characterized by being provided. 8. The method for producing a paste composed of coal and water according to claim 5, 6 or 7, wherein at least one of a microwave moisture meter and an infrared moisture meter is used for measuring the moisture content of the crushed coal. A method for producing a paste composed of coal and water, characterized by using.