JP4557445B2 - Method of operating fluidized bed boiler device and fluidized bed boiler device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for operating a fluidized bed boiler apparatus and a fluidized bed boiler apparatus suitable for achieving uniform temperature distribution in a fluidized bed when combustible waste is burned in a fluidized bed boiler.
[0002]
[Prior art]
In a fluidized bed boiler apparatus, coal is combusted in a fluidized bed boiler, and the heat generated from the combustion heats a heat transfer tube installed in the boiler to generate steam in the heat transfer tube. In a fluidized bed boiler, it is necessary to make the temperature distribution in the fluidized bed uniform so that the heat transfer tube does not burn out due to local combustion of fuel. Generally, the fuel supplied to the fluidized bed boiler has a characteristic that it is difficult to disperse in the horizontal direction. For this reason, a plurality of fuel supply devices are arranged in the horizontal direction. The number of fuel supply devices is generally proportional to the cross-sectional area of the fluidized bed boiler.
[0003]
The supplied fuel is made into a paste by mixing coal and water so as not to burn before being dispersed in the fluidized bed, and is supplied to the fluidized bed boiler by a fuel supply pump. The amount of fuel supplied is controlled so that the temperature in the fluidized bed becomes a predetermined value in order to keep the generated steam in the heat transfer tube constant.
[0004]
The combustion air for burning the fuel uses the flowing air that is input to form the fluidized bed, and is supplied from the lower part of the boiler. The residual oxygen concentration in the combustion gas is measured by an oxygen concentration meter installed at the boiler outlet. The supply amount of the combustion air is controlled so that the residual oxygen concentration becomes a specified value, that is, the air-fuel ratio (ratio between the fuel flow rate and the combustion air flow rate) is constant.
[0005]
[Problems to be solved by the invention]
By the way, when burning garbage with a fluidized bed boiler, if only garbage is burned as fuel, the amount of heat generated fluctuates because garbage is mixed with non-burnable garbage such as garbage, and the amount of evaporation in the heat transfer tube Is difficult to keep constant.
[0006]
For this reason, it becomes indispensable to burn garbage in a fluidized bed boiler in combination with a fuel such as coal having a stable calorific value. However, if different types of coal and garbage are burned by such a combustion method, it is difficult to achieve a proper combustion state for each.
[0007]
An object of the present invention is to solve the above-described problems of the prior art and provide a fluidized bed boiler apparatus operating method and a fluidized bed boiler apparatus capable of stably burning garbage in a fluidized bed boiler. .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the fluidized bed boiler operating method according to the present invention comprises a paste-like fuel obtained by kneading coal and water, combusting and mixing combustible waste, and mixing the mixed fuel. It is characterized by being supplied to a fluidized bed boiler and combusted.
[0009]
Further, the fluidized bed boiler operating method of the present invention is such that when the paste-like fuel obtained by kneading coal and water is burned in the fluidized bed boiler, the combustible waste that has been pulverized is compressed with compressed air. The mixed fuel is supplied to a fluidized bed boiler and burned.
[0010]
In a fluidized bed boiler, pulverized combustible waste (garbage) mixed with paste fuel obtained by mixing coal and water and supplied to the fluidized bed, combustible waste mixed with paste fuel Things spread evenly in the fluidized bed. As a result, local combustion is avoided in the fluidized bed, and combustion occurs uniformly. In this case, paste-like fuel mixed with combustible waste may be supplied to the lower part of the fluidized bed. In this way, it is possible to secure a residence time necessary for combustion of combustible waste, and it is possible to completely burn both coal and combustible waste.
[0011]
Dispersed air (compressed air) is supplied when mixing pulverized combustible waste with fuel in which coal and water are mixed in a paste. In this way, a space is formed in the paste-like fuel by the dispersed air, and the combustible waste pulverized pieces are replaced in the space, and good mixing with the paste-like fuel becomes possible. FIG. 2 shows a case where combustible waste is supplied to the paste-like fuel together with the dispersed air.
[0012]
Moreover, it is good to measure the temperature of several places in a fluidized bed, and to adjust the mixing amount of a combustible waste based on the measurement result. For example, the temperature of the fluidized bed is measured at a plurality of locations in the vicinity of each fuel supply device, the measured value is compared with the target value, and the mixing amount of the combustible waste to be supplied is adjusted. This makes it possible to adjust the combustion characteristics due to the difference in the calorific value of the combustible waste.
[0013]
Further, the fluidized bed boiler apparatus of the present invention is connected to a fluidized bed boiler, and a main fuel supply system for supplying paste-like fuel obtained by kneading coal and water to the fluidized bed boiler; A secondary fuel supply system connected to the middle of the fuel supply system and configured to supply pulverized combustible waste and compressed air to the main fuel supply system. Combustible waste supplied from a fuel supply system and compressed air are mixed, and the mixed fuel is supplied to the fluidized bed boiler through the main fuel supply system and burned. In addition, you may supply compressed air to the paste-like fuel obtained by mixing coal and water beforehand.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall system of a fluidized bed boiler apparatus according to the present invention. As shown in FIG. 1, in the fluidized bed boiler 1, combustion air 2 is introduced from the lower part, and the fuel supplied from the fuel supply device 3 is burned in the fluidized bed 4. The flow rate of the combustion air 2 is measured by an air flow meter 1A. The fluidized bed boiler 1 is provided with a heat transfer tube 5 in which water flows, and the water in the heat transfer tube 5 is heated by combustion in the fluidized bed 4 to generate steam. The generated steam drives the steam turbine 6, and the steam turbine 6 further drives the generator 7.
[0015]
The fuel supplied from the fuel supply device 3 is supplied to the lower part of the fluidized bed 4 as a paste-like fuel by mixing water 9 with the coal 8 so as not to burn before being dispersed in the fluidized bed 4. . A fuel supply pipe 11 having a fuel supply pump 10 is connected to the fuel supply apparatus 3 on the way, and the paste-like fuel is pressurized by the fuel supply pump 9 and is supplied to the fuel supply apparatus 3 via the fuel supply pipe 11. Being transported. The flow rate of the pasty fuel is measured by a fuel flow meter 8A. A plurality of fuel supply devices 3 are installed below the fluidized bed boiler 1.
[0016]
A plurality of bed thermometers 12 for measuring the temperature in the fluidized bed 4 are provided below the fluidized bed boiler 1. The fuel supply from the fuel supply device 3 is controlled so that the temperature detected by the bed thermometer 12 becomes a specified temperature, and thereby the generated steam in the heat transfer tube 5 is kept constant. An oxygen concentration meter 14 for measuring the residual oxygen concentration in the combustion gas 13 is provided at the boiler outlet. The inflow amount of the combustion air 2 is controlled so that the residual oxygen concentration becomes a specified value.
[0017]
When the garbage 17 which is combustible waste is burned in the fluidized bed boiler 1, the received garbage 17 is sent to the garbage pretreatment facility 16 and pretreated so as to be combustible in the fluidized bed boiler. The garbage pretreatment facility includes a bag breaker 18, a primary magnetic separator 19, a primary crusher 20, a dryer 21, a secondary magnetic separator 22, an aluminum magnetic separator 23, a wind separator 24, and a secondary pulverizer 25. Yes.
[0018]
The garbage 17 received by the garbage pretreatment facility 16 is generally packed in a bag, so that it is broken by the bag breaking machine 18 to remove foreign matters contained in the garbage 17. Then, iron that is inappropriate for combustion is removed by the primary magnetic separator 19 and further crushed by the primary crusher 20. By crushing the garbage, the drying efficiency in the dryer 21 is improved, and the non-combustible material can be easily removed in the downstream sorting process. Then, after iron, aluminum, and incombustible materials are removed by the secondary magnetic separator 22, the aluminum magnetic separator 23, and the wind separator 24, respectively, the waste is pulverized by the secondary pulverizer 25. The secondary pulverizer 25 pulverizes to about 1/3 or less of the inner diameter of the fuel supply device 3 so as not to cause clogging in the fuel supply system. Water 9 is poured into the crushed waste, and the waste is mixed with water to form a paste.
[0019]
The process from the bag breaking to the secondary pulverization is the same as the general solid waste fuel production process, but a part of the equipment can be deleted depending on the nature of the accepted waste. In another apparatus, waste in the form of solid fuel can be used.
[0020]
One end of a pulverized waste transport pipe 27 is connected to the secondary pulverizer 25, and the other end of the pulverized waste transport pipe 27 is connected to the fuel supply pipe 11. Then, the paste-like pulverized waste is pumped by the pulverized waste supply pump 28 provided in the middle of the pulverized waste transport pipe 27 and supplied to the fuel supply pipe 11. In this case, dispersed air 29, which is compressed air, is injected into the pulverized waste transport pipe 27 on the downstream side of the pulverized waste supply pump 28.
[0021]
In the fuel supply pipe 11, paste-like fuel in which coal 8 and water 9 are mixed is present. When paste-like pulverized waste is supplied to the fuel supply pipe 11 together with the dispersed air 29, the dispersed air 29 A space is formed in the paste-like fuel, and crushed garbage is replaced in the space. Thereby, good mixing of the paste-like fuel and the pulverized waste becomes possible. In the present embodiment, an example is shown in which the dispersed air 29 is injected into the pulverized waste transport pipe 27. However, the dispersed air is injected into the fuel supply pipe 11 to form a space in the pasty fuel in advance. It is also possible to mix pulverized waste with the pasty fuel.
[0022]
The mixed fuel of coal and waste is uniformly supplied from the fuel supply device 3 to the lower part of the fluidized bed 4, and does not burn locally but burns uniformly in the fluidized bed 4. Moreover, by supplying from the fuel supply device 3 provided in the lower part of the fluidized bed boiler 1, a residence time required for combustion can be ensured, and the supplied waste can be completely burned.
[0023]
Garbage 17 consists of various combustible wastes, such as garbage, and the calorific value changes. Therefore, in order to keep the evaporation amount in the heat transfer tube 5 constant, the amount of the waste 17 to be supplied is 10% of the coal amount in consideration of the influence degree of the fluctuation of the heat input amount to the boiler due to the fluctuation of the heat generation amount of the waste. It is good to make it about% or less.
[0024]
In the fluidized bed boiler 1, since it is necessary to make the temperature distribution in the fluidized bed 4 uniform so that the heat transfer tube 5 does not burn out due to local combustion of the fuel, a plurality of fuel supply devices 3 are arranged in a horizontal plane. ing. At this time, by adjusting the mixing amount of the waste 17 to be supplied so that the temperature of the bed thermometer 12 installed in the vicinity of each fuel supply device 3 becomes a specified temperature, the combustion characteristics due to the difference in the heat generation amount of the waste Can be adjusted.
[0025]
In the present embodiment, the fuel supply pump 10, the fuel supply pipe 11, and the fuel supply device 3 constitute a main fuel supply system, and the pulverized garbage transport pipe 27 and the pulverized garbage supply pump 28 constitute an auxiliary fuel supply system. Yes.
[0026]
Further, in this embodiment, paste-like pulverized waste and dispersed air are supplied to one of the fuel supply pipes 11, but paste-like pulverized garbage and dispersed air are supplied to a plurality of fuel supply pipes 11. Thus, the bed temperature in the fluidized bed 4 can be kept uniform by the same control.
[0027]
【The invention's effect】
As described above, according to the present invention, in the fluidized bed boiler, it is possible to mix the waste with the fuel so that it can be burned uniformly and completely.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an entire system of a fluidized bed boiler apparatus according to the present invention.
FIG. 2 is an explanatory view showing the principle of mixing pulverized waste with paste-like fuel.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fluidized bed boiler 3 Fuel supply apparatus 4 Fluidized bed 5 Heat transfer pipe 8 Coal 9 Water 10 Fuel supply pump 11 Fuel supply piping 12 Bed thermometer 14 Oxygen concentration meter 16 Waste pretreatment equipment 27 Ground waste conveyance piping 28 Ground waste supply pump 29 Dispersed air

Claims (5)

  When the paste-like fuel obtained by kneading coal and water is burned in the fluidized bed boiler, the combustible waste and the paste-like fuel are mixed with compressed air and the mixed fuel is supplied to the fluidized bed boiler. And operating the fluidized bed boiler device.   The operation method of a fluidized bed boiler apparatus according to claim 1, wherein the mixed fuel is supplied to a lower part of the fluidized bed.   The fluidized bed boiler apparatus operating method according to claim 1, wherein the temperature of a plurality of locations in the fluidized bed is measured, and the mixing amount of the combustible waste is adjusted based on the measurement result. Operation method of the layer boiler device.   A main fuel supply system connected to a fluidized bed boiler for supplying paste fluid obtained by kneading coal and water to the fluidized bed boiler, and connected in the middle of the main fuel supply system and pulverized. A combustible waste and a secondary fuel supply system for supplying compressed air to the main fuel supply system, and the combustible waste supplied from the secondary fuel supply system to the paste-like fuel in the main fuel supply system And the compressed air are mixed, and the mixed fuel is supplied to the fluidized bed boiler through the main fuel supply system and burned. It is connected to the fluidized bed boiler, the fuel supply pipe and pasty fuel obtained by mixing the coal with water compressed air you supplied to the fluidized bed boiler is connected to the middle of the fuel supply pipe and ground A transfer pipe for supplying combustible waste to the fuel supply pipe , the compressed air is injected into the paste-like fuel in the fuel supply pipe, and the transfer pipe is supplied to the paste-like fuel into which the compressed air is injected A fluidized bed boiler apparatus comprising: mixing flammable waste supplied from a fuel supply unit;

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