JP4362577B2 - Waste incineration equipment - Google Patents

Description

  The present invention relates to a waste incineration facility that performs incineration processing of waste such as municipal waste.

Some waste incineration facilities that incinerate waste such as municipal waste are provided with a gas cooling chamber that cools exhaust gas by spraying cooling water onto exhaust gas generated by combustion of waste (for example, (See Patent Document 1). An example of the equipment provided with such a gas cooling chamber is shown in FIG. In this waste incineration facility, a fluidized bed 2 composed of a fluidized medium layer is formed at the bottom of the incinerator 1, and a certain amount of fluidized air (primary combustion air) that causes the fluidized medium to flow and waste that is input to the incinerator 1. The amount of secondary combustion air corresponding to the properties of the air is blown into the incinerator 1 to burn the waste. The flowing air is blown into the incinerator 1 from the primary blower 3 and the secondary combustion air is blown from the secondary blower 4 through the blow passages 5 and 6, respectively.
JP 2004-278819 A

  A gas cooling chamber 7 is provided immediately above the incinerator 1, and cooling water is sprayed from the water spray device 8 to the exhaust gas in the gas cooling chamber 7 to cool the exhaust gas. The cooled exhaust gas flows into a discharge pipe 9 connected to the gas cooling chamber 7, passes through a primary air preheater 10 provided in the middle of the discharge pipe 9, and is discharged outside the facility. Then, in order to prevent the preheater 10 from being overheated by the exhaust gas and to ensure the amount of heat recovered by the preheater 10, water spray is performed so that the exhaust gas temperature measured by the thermometer 11 at the inlet of the discharge pipe 9 becomes the set temperature. The amount of gas cooling water spraying is adjusted by changing the opening degree of the valve 13 attached between the device 8 and the water pump 12.

  Further, in the incinerator 1, the amount of secondary combustion air required for stable combustion varies depending on the properties of the input waste, so that two dampers 14, 15 are arranged in parallel in the secondary combustion air blowing path 6. The first damper 14 is controlled so that the oxygen concentration measured by the oxygen concentration meter 16 at the outlet of the incinerator 1 becomes a set value, or the incinerator measured by the radiation thermometer 17 at the center of the incinerator 1 An appropriate amount of secondary combustion air is always blown into the incinerator 1 by controlling the second damper 15 based on the frame brightness within 1, or by controlling these two dampers 14 and 15 simultaneously. Like that.

  By the way, in this kind of waste incineration equipment, the calorific value of the input waste usually varies greatly depending on its properties, so the design of the incinerator is based on high-quality waste such as paper and plastic with a large calorific value. It is carried out. Therefore, in particular, when the gas cooling chamber is provided directly above the incinerator as shown in FIG. 2, if a large amount of low-quality waste with a small calorific value, such as those containing a large amount of soot and moisture, is introduced into the incinerator, The combustion state tends to become unstable due to the influence of cooling water. In other words, when low-quality waste is charged, the amount of heat generated from the gas cooling water is reduced to a certain extent because the amount of heat generated is small. Since the amount of water is greatly reduced, the evaporation time becomes longer due to a decrease in the gas flow rate, and the action of entraining the droplets is lowered. It will be reduced to inhibit stable combustion.

  On the other hand, if the amount of secondary combustion air injected is constant regardless of the properties of the waste, the reduction in the amount of exhaust gas when low-quality waste is charged can be suppressed, but the secondary combustion air injected more than necessary Since the temperature in the furnace is lowered, the combustion state is also unstable.

  An object of the present invention is to stabilize a combustion state of an incinerator by preventing a decrease in furnace temperature due to gas cooling water in a waste incineration facility in which a gas cooling chamber is provided immediately above an incinerator.

  In order to solve the above problems, the present invention provides a gas cooling chamber immediately above an incinerator for burning waste, and sprays cooling water onto the exhaust gas generated by the combustion of the waste in the gas cooling chamber. In the waste incineration facility that cools the air, a part of the air that is branched from this air passage and is sent from the secondary air blower upstream of the air passage in the middle of the air passage that blows secondary combustion air into the incinerator A branch for blowing into the gas cooling chamber is provided, and the total amount of air supplied to the incinerator and the gas cooling chamber by the secondary blower is made constant, and the supply amount of the air to the incinerator and the supply to the gas cooling chamber The amount distribution rate can be adjusted according to the properties of the waste to be put into the incinerator.

  That is, a part of the air supplied by the secondary blower can be blown into the gas cooling chamber as gas cooling air, and the total amount of air supply by the secondary blower is kept constant, and the required amount of secondary combustion air is small When low-quality waste is thrown in, most of the air sent from the secondary blower is blown into the gas cooling chamber, and the exhaust gas discharged from the incinerator is cooled with this gas cooling air, and sprayed in the gas cooling chamber. The amount of cooling water was reduced to prevent the cooling water from flowing into the incinerator, so that the furnace temperature could be maintained properly at all times. On the other hand, when high-quality waste is introduced, as in the prior art, most of the air from the secondary blower may be blown into the incinerator as secondary combustion air. At this time, the gas cooling water cannot be reduced, but the amount of exhaust gas generated increases, so that the cooling water hardly flows into the incinerator.

  In the above configuration, if the air blowing position from the branch of the blower passage to the gas cooling chamber is the inlet of the gas cooling chamber, the exhaust gas discharged from the incinerator is cooled more effectively with the gas cooling air. The amount of gas cooling water spray can be further reduced.

  The air supplied from the secondary blower to the incinerator and the gas cooling chamber is supplied to the incinerator with the required amount of secondary combustion air corresponding to the properties of the waste, and the remainder is supplied to the gas cooling chamber. It is good to distribute so that.

  In the waste incineration facility of the present invention, the total amount of air supply by the secondary blower is made constant, and the distribution rate of the supply amount of the air to the incinerator and the supply amount to the gas cooling chamber according to the property of the waste This makes it possible to adjust the amount of air supplied to the gas cooling chamber (the amount of gas cooling air) to reduce the gas cooling water and prevent the furnace temperature from falling when low-quality waste is introduced. The combustion state of the incinerator can be stabilized. Further, since the fluctuation of the amount of exhaust gas due to the property of the waste can be reduced as compared with the conventional case, the pressure in the furnace is stabilized, and this can also stabilize the combustion state.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. Since the basic configuration of this waste incineration facility is the same as that of the conventional facility shown in FIG. 2, members having the same function are denoted by the same reference numerals, and the description thereof is omitted. Will be described.

  As shown in FIG. 1, the air passage 6 for secondary combustion air is provided with a branch passage 6 a that branches in the middle of the air passage 6 and reaches the inlet of the gas cooling chamber 7, and is sent from the secondary blower 4. Part of the air is blown into the gas cooling chamber 7 as gas cooling air through the branch 6a. The air blowing direction from the branch path 6 a to the gas cooling chamber 7 is a direction along the inner wall of the gas cooling chamber 7. This is to reduce the amount of dust adhering to the gas cooling chamber 7 and prevent the combustion state from becoming unstable due to the dust lump falling into the incinerator 1.

  Further, like the conventional equipment, the incinerator 1 is supplied with the required amount of secondary combustion air from the secondary blower 4 according to the properties of the waste. Then, the flow rate is measured by the flow meter 18 upstream of the branch point of the secondary combustion air blowing passage 6 with the branch passage 6a, and the opening degree of the valve 19 attached to the branch passage 6a is adjusted. The total amount of air supplied to the incinerator 1 and the gas cooling chamber 7 by the secondary blower 4 is controlled to be constant (approximately 1.1 times the amount of secondary combustion air required when high-quality waste is charged). .

  Specifically, when high-quality waste is charged, the amount of heat generated in the incinerator 1 increases, so that the opening degree of at least one of the two dampers 14 and 15 of the secondary combustion air blowing passage 6 is increased for incineration. While increasing the secondary combustion air supply amount Qb to the furnace 1 and reducing the opening of the valve 19 of the branch 6a to reduce the gas cooling air supply amount Qa to the gas cooling chamber 7, the secondary blower 4 The supply air total amount Q (= Qa + Qb) is kept constant. On the other hand, when low-quality waste is introduced, the amount of generated heat is reduced, so that at least one damper opening is reduced to reduce the air supply amount Qb to the incinerator 1 and the opening of the valve 19 of the branch 6a. The air supply amount Qa to the gas cooling chamber 7 is increased to increase the total supply air amount Q of the secondary blower 4.

  That is, the total amount of air sent from the secondary blower 4 is constant, the required amount of secondary combustion air according to the properties of the waste is supplied to the incinerator 1, and the remainder is supplied to the gas cooling chamber 7. Therefore, when low-quality waste with a small amount of secondary combustion air is introduced, most of the air sent from the secondary blower 4 is blown into the gas cooling chamber 7 inlet as gas cooling air, and the incinerator 1 The exhaust gas discharged from the air will be cooled. As a result, the amount of gas cooling water sprayed is reduced.

  Next, Table 1 shows an example of calculating the amount of gas cooling water spray for each waste property. This calculation example is for an incinerator having an incineration capacity of 20 ton / 16h.

  In the calculation example of Table 1, the gas cooling water spray amount becomes 0 kg / h when low-quality waste is charged, so there is no possibility that the furnace temperature decreases due to the influence of the gas cooling water as in the conventional case. In addition, the amount of exhaust gas when low-quality waste is charged is about 50% of the conventional equipment when high-quality waste is charged, whereas this equipment is about 80% when high-quality waste is charged. Fluctuation in the amount of exhaust gas due to is greatly reduced.

  This waste incineration equipment is configured as described above, and when low-quality waste is thrown in, the amount of air supplied to the gas cooling chamber 7 is increased to reduce the amount of gas cooling water spray. A decrease in furnace temperature due to inflow can be prevented, and a stable combustion state can be obtained regardless of the properties of the waste. In addition, the variation in the amount of exhaust gas due to the properties of the waste is greatly reduced as compared with the conventional case, and the furnace pressure is stabilized. This also stabilizes the combustion state.

  In addition, this invention is applicable not only to the fluid bed type waste incineration equipment like embodiment but to a stoker type incineration equipment. Moreover, if the present invention is applied to an incinerator of a type in which the gas cooling chamber and the incinerator are separated, there will be no effect on the temperature in the furnace, but dust adhesion due to cooling water in the gas cooling chamber or the gas cooling chamber Troubles such as an ash transport device due to the wetness of the precipitated ash discharged from the ash can be prevented.

Schematic of the waste incineration facility of the embodiment Schematic of an example of conventional waste incineration equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incinerator 2 Fluidized bed 3, 4 Blower 5, 6 Blower path 6a Branch 7 Gas cooling chamber 8 Water spray apparatus 9 Discharge pipe 10 Primary air preheater 11 Thermometer 12 Water pump 13 Valves 14, 15 Damper 16 Oxygen meter 17 Radiation thermometer 18 Flow meter 19 Valve

Claims (2)

A gas cooling chamber is provided immediately above the incinerator for burning waste, and cooling water is sprayed on the exhaust gas generated by the combustion of waste in the gas cooling chamber to cool the exhaust gas, which is discharged from the gas cooling chamber. In the waste incineration facility that adjusts the spray amount of the cooling water so that the temperature of the exhaust gas becomes the set temperature, the air is branched from this air passage in the middle of the air passage that blows secondary combustion air into the incinerator. A branch passage for blowing a part of the air sent from the secondary blower upstream of the road into the gas cooling chamber is provided, and the total amount of air supplied to the incinerator and the gas cooling chamber by the secondary blower is made constant, Distributing the air supplied by the secondary blower so that the required amount of secondary combustion air according to the properties of the waste is supplied to the incinerator and the remainder is supplied to the gas cooling chamber. Waste incineration equipment. The waste incineration facility according to claim 1, wherein an air blowing position from a branch of the air passage to the gas cooling chamber is an inlet portion of the gas cooling chamber.

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