JP2944502B2 - Garbage incineration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refuse incinerator provided with a combustion type superheater, and more particularly, to a waste heat boiler for recovering waste heat from exhaust gas generated in an incinerator and generating steam, and the generated steam. And a power generator that generates power by driving a turbine according to the present invention, and a combustion type superheater that superheats steam in the path in a steam supply path from the waste heat boiler to the power generator.

[0002]

2. Description of the Related Art In a conventional refuse incinerator, a combustion type superheater is provided for the purpose of increasing the efficiency of a steam turbine by superheating steam generated in a waste heat boiler, and the combustion exhaust gas is preheated by air. A vessel was provided to recover heat and then released outside the system. However, in the above-described refuse incineration apparatus, the refuse to be incinerated may include garbage from households, or may include non-combustible or non-flammable substances. Usually, the amount of generated steam fluctuates due to fluctuations in the combustion state, and when the amount of generated steam in the waste heat boiler decreases, the insufficient steam amount is supplemented by water spray in the combustion type superheater, When the amount increased, the amount of power generation was stabilized by limiting the steam input to the turbine. However, as described above, since the quality of the incinerated material as a combustion heat source is unstable, the heat load of the combustion type superheater fluctuates greatly, and the combustor of the combustion type superheater burns due to excess air supply. While increasing the temperature, the inner surface of the peripheral wall is cooled by air to protect the peripheral wall of the combustion chamber,
The combustion gas is diluted and cooled by the cooling air, and the temperature of the superheating gas is set to, for example, 9 by adjusting the flow rate of the cooling air.
Adjustment to 00 ° C. has been performed.

[0003]

In the above-described conventional refuse incinerator, the amount of fuel required to maintain the temperature of the gas at the outlet of the combustor tends to increase in order to supply excess air to the combustor. There has been a fuel economy problem that the amount of heat (exhaust gas loss) brought out by the released combustion exhaust gas increases as the amount of combustion exhaust gas increases due to excess air supply. In order to reduce this exhaust gas loss, it is considered to use it for preheating the air supplied to the combustor and supply high temperature combustion exhaust gas with high residual oxygen concentration as secondary combustion gas for the incinerator. However, the exhaust gas loss has not been sufficiently recovered. Incidentally, in the conventional refuse incineration apparatus, in order to improve the heat transfer efficiency between the combustion gas and the steam, the cooling air is increased in order to increase the flow rate of the gas passing through the superheat path and to increase the amount of the combustion gas. In order to maintain the temperature of the combustion exhaust gas at the combustor outlet constant, it was necessary to increase the fuel supply amount in order to replenish the calorific value for the cooling. This will increase or alter the excess air ratio in the combustor, which may interfere with maintaining the stability of the combustion conditions, and alter the temperature of the combustion gas at the combustion chamber outlet. As a result, there was a problem of increasing fuel consumption. Accordingly, an object of the present invention is to solve the above-mentioned problems and improve the controllability while maintaining good exhaust gas characteristics of a combustion type superheater, and at the same time reduce the exhaust gas loss, thereby achieving good fuel economy garbage incineration. Equipment.

[0004]

[Operation and effect of first characteristic configuration]

Therefore, according to the first characteristic configuration, when the combustion exhaust gas cooled by superheating the steam is used to cool the combustion gas in the combustion chamber, the temperature of the inlet of the combustion type superheater of the cooling gas and the temperature of the outlet of the combustion type superheater are reduced. There is no difference between the temperature and, therefore, there is no need to heat the cooling gas to the superheater outlet temperature. For example, if the combustor outlet temperature is 300 ° C., 30
When the combustion exhaust gas at 0 ° C. is used as the cooling gas, even if the combustion chamber outlet temperature is 900 ° C., considering only the cooling gas, the inlet temperature and the outlet temperature are both 300 ° C. No heat is required to heat the gas to the combustor exit temperature. However, when using the combustion air as the cooling gas, even if the preheated air preheated to 200 ° C. is used, the cooling gas is heated up to the combustor outlet temperature of 300 ° C., that is, the cooling gas is heated up to 100 ° C. Requires the amount of heat to be heated. Thus, with the above configuration, complete combustion in the combustor can be maintained at a low air ratio, and the amount of heat for heating the cooling gas can be reduced. As a result, the amount of heat carried by the exhaust gas as an exhaust gas loss does not include the amount of heat required to overheat the cooling gas, and the exhaust gas loss can be reduced accordingly. The purpose of maintaining the combustion chamber outlet temperature at, for example, 900 ° C. is one of the objectives to minimize the concentration of carbon monoxide in the exhaust gas at the outlet of the superheater. It is possible to keep the temperature constant. Further, the supply of the cooling gas may not affect the oxygen concentration in the combustion gas, and as a result, the required amount of heating heat per unit flow rate of the cooling gas is reduced. Can be supplied, and the flow velocity of the gas passing through the superheat path can be increased, so that the heat transfer efficiency between the passing gas and the steam in the superheat path can be improved. Therefore, the same superheated steam condition can be satisfied even if the fuel supply amount is reduced as compared with the conventional method, in order to supply the combustion gas at the same temperature to the superheat path at a relatively high flow rate. In other words, by using the exhaust gas of the steam superheater as the cooling gas, it is possible to keep the temperature of the exhaust gas from the combustor constant while preventing the amount of heat supplied to the superheat path from being excessive or insufficient. Further, the improvement of the heat transfer efficiency can improve the responsiveness of the superheater which copes with the fluctuation of the heat input to the waste heat boiler having a large time constant, so that the controllability of the refuse incinerator is improved.

Further , the combustion chamber is divided into a main combustion chamber and a post-combustion chamber, and a combustion gas diffusion mechanism is provided between the combustion chamber and the post-combustion chamber so that the combustion gas in the main combustion chamber and the post-combustion chamber are separated from each other. and recirculating exhaust gases from an exhaust gas circulation passage by mixing the diffusion, because it is constituted such that it made the post-combustion in the post-combustion chamber, wherein it is mixed and circulated exhaust gas and the combustion gas by said combustion gas diffusion mechanism, Even if the excess air coefficient of the air supplied to the combustor provided in the combustion chamber is extremely low, the high-temperature combustion gas in the main combustion chamber is stirred and diluted, and the temperature decreases and the combustion gas before stirring dilution is simultaneously reduced. The unreacted carbon monoxide and the residual oxygen in the combustion gas and the residual oxygen in the circulating exhaust gas make contact with the post-combustion chamber, so that the fuel supplied to the combustion chamber is completely burned. , Combustion chamber outlet It is possible to maintain the burn exhaust gas temperature to a desired temperature. For example, even if the excess air coefficient of the air supplied to the combustor provided in the combustion chamber is 1.1, the combustion gas at 1500 ° C in the main combustion chamber is stirred and diluted with the combustion exhaust gas at 300 ° C. Although the temperature decreases, the carbon monoxide in the combustion gas before the stirring and dilution comes into contact with the residual oxygen to perform post-combustion, so that the temperature of the exhaust gas at the combustion chamber outlet can be maintained at, for example, 900 ° C. The exemplified combustion exhaust gas temperature is a temperature at which the amount of generated carbon monoxide is minimized and the steel pipe used for the superheat path is set so as not to use a special material. In other words, the circulating amount of the circulating exhaust gas is adjusted so as to maintain the combustion chamber outlet temperature of the post-combustion exhaust gas at a predetermined temperature without relying on the cooling of the combustion gas temperature in the main combustion chamber using excess air. The exhaust gas temperature can be controlled by controlling the temperature of the combustion exhaust gas at the outlet of the combustion chamber, so that the fuel supply amount is controlled so as to follow the fluctuation of the steam amount supplied from the waste heat boiler, and the air supply amount is adjusted so as to conform to the fluctuation. Can be reduced. In other words, the amount of exhaust gas from the combustion type superheater to the outside of the system is only the amount corresponding to the fuel supply amount and the supply amount of combustion air supplied along with the fuel supply amount. I will not receive it. As a result, combustion
The controllability of the superheater is improved and the exhaust gas loss is reduced.
Good fuel economy with reduced fuel consumption
Garbage incinerator could be provided.

[Second characteristic configuration and operation and effect] As a second characteristic configuration of the refuse incineration apparatus of the present invention, the supply of the circulating exhaust gas to the inside in the vicinity of the combustion gas diffusion mechanism in the first characteristic configuration is described . It is more preferable that a diffusion exhaust gas path having a portion is provided (corresponding to claim 2 ). In this case, the stirring and mixing of the combustion gas and the circulating exhaust gas by the combustion gas diffusion mechanism is further promoted. As a result, the cooling gas is supplied only to protect the peripheral wall of the main combustion chamber, and while maintaining the flow rate suitable for the combustion gas temperature in the main combustion chamber, the circulating exhaust gas from the diffusion exhaust gas passage is maintained. By adjusting the amount, the temperature of the flue gas at the combustion chamber outlet can be arbitrarily adjusted. Therefore, it becomes easier to control the temperature and flow rate of the superheating combustion gas in accordance with the flow rate of the steam from the waste heat boiler supplied to the steam superheating path of the combustion type superheater. Therefore, the temperature of the combustion exhaust gas at the outlet of the combustion chamber can be kept constant and the temperature of the superheated steam can be stabilized irrespective of a change in the fuel supply amount or other changes within the appropriate range. As a result, it becomes possible to provide a refuse incinerator with good controllability and good fuel economy while maintaining good exhaust gas characteristics of the combustion type superheater in the first characteristic configuration . [Third characteristic configuration and operation and effect] The third characteristic configuration of the refuse incineration apparatus of the present invention is a combustion type.
The flue gas from the superheater is sent to the combustion chamber of the combustion type superheater.
Provide an exhaust gas circulation path to be introduced, the combustion chamber and the main combustion chamber
The main combustion chamber and the post-combustion chamber are formed separately in a post-combustion chamber.
Between the circulation exhaust gas toward the inside of the combustion chamber
Providing a diffusion exhaust gas path with a supply section, said main combustion chamber
Mixed with the exhaust gas from the exhaust gas circuit
So as to perform post-combustion in the post-combustion chamber.
(Corresponding to claim 3). Therefore, the third feature
According to the feature, the supply of the diffusion exhaust gas is
It can contribute to the stirring and to make the temperature uniform. As a result,
At the same time as improving the controllability of the incinerator type superheater,
Good fuel economy with reduced fuel consumption
A good garbage incinerator could be provided.

[Fourth characteristic configuration and operation and effect] As a fourth characteristic configuration of the refuse incinerator of the present invention,
A combustion gas temperature detecting means is provided downstream of the combustion chamber in any one of the first to third characteristic configurations, and a circulating amount of the circulating exhaust gas from the exhaust gas circulation path is determined based on a detection result of the combustion gas temperature detecting means. And means for controlling the amount of exhaust gas circulating to adjust the temperature of the combustion gas from the post-combustion chamber to be introduced into the steam superheating path.
It is even better if the exhaust gas circulation amount adjusting means is linked to the detection result of the combustion gas temperature detecting means, so that the fuel supply amount corresponds to the steam amount from the waste heat boiler supplied to the steam superheating path. The temperature of the combustion gas to the steam superheating path can be controlled by the control means without being affected by the combustion state in the furnace of the refuse incinerator. As a result, while maintaining the exhaust gas characteristics of the combustion type superheater in each of the above-described first characteristic configurations, and maintaining the controllability, the power generation amount of the power generation device that is turbine-driven by the steam from the waste heat boiler is stabilized. A garbage incinerator can be provided.

[Fifth characteristic configuration and operation and effect] Further, as a fifth characteristic configuration of the refuse incineration apparatus of the present invention,
The air supply amount to the combustor of the combustion type superheater is adjusted based on the detection result of the oxygen content in the combustion exhaust gas from the exhaust gas detection means provided in the combustion type superheater according to any one of the first to fourth aspects. It is better if the control means is provided in the control means (corresponding to claim 5). In this case, the amount of oxygen remaining in the combustion exhaust gas of the combustion type superheater can be kept constant. Since the supply of excess air can be suppressed, the exhaust gas loss can be further reduced. Note that this is because the proportion of oxygen remaining in the combustion exhaust gas after complete combustion of the fuel in the combustion chamber depends on the excess air coefficient, and the combustion exhaust gas in the path extending from the combustion chamber outlet to the exhaust gas circulation path. Since the residual oxygen amount is substantially constant, the combustion gas temperature at the combustion chamber outlet is kept constant, and
It is based on the fact that if the excess air coefficient of the air supplied to the combustor is kept constant, the amount of residual oxygen in the combustion exhaust gas will be almost constant, and if the combustion is completely completed in the combustion chamber, Since the predetermined oxygen content is detected by the exhaust gas detecting means, the combustion state in the combustion chamber can be estimated from the detected oxygen content, and a direction for improving the combustion state, or a good combustion state is determined. It is possible to control the air supply amount in a direction to minimize the supply air amount while maintaining it. As a result, it is possible to provide a refuse incinerator that maintains controllability and further improves fuel economy while maintaining the exhaust gas characteristics of the combustion type superheater in each of the above-described first characteristic configurations.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of an embodiment of the refuse incinerator according to the present invention will be described below with reference to the drawings. As shown in FIG. 2, the garbage incinerator includes a stoker-type incinerator 1 for incinerating municipal garbage, an exhaust gas treatment device 2 for purifying exhaust gas generated from the incinerator 1, and heat of the exhaust gas. The power generation device 3 is configured to generate power.

The incinerator 1 includes a hopper H for receiving the incinerated material, a pusher Pu for injecting municipal garbage, which is an incinerated material in the hopper H, from the lower end into the incinerator, and an incinerator charged by the pusher Pu. While stirring and transporting the material, a stoker S is sequentially provided for drying, burning, and incineration with high-temperature primary combustion air supplied from the bottom of the stoker S, and an upper portion of the stoker S is provided to complete the combustion of the unburned gas. A secondary combustion space 7 is formed in the space, and a secondary combustion gas supply unit 9 for supplying a secondary combustion gas to the space 7 is provided facing the space 7 and a downstream side of the space 7 is provided. In space 8,
A waste heat boiler 6 for recovering the thermal energy of the combustion exhaust gas is provided.

The exhaust gas treatment device 2 comprises a bag filter 2a, a smoke washing device 2b, and the like provided in the middle of the flow path from the exhaust gas passage 4 provided downstream of the space 8 to the chimney 5.

The power generator 3 comprises a steam turbine 10 and a generator G connected to an output shaft of the steam turbine 10. Steam of about 6 MPa and 300 ° C. generated from the waste heat boiler 6 is passed through a main steam path. The steam is supplied to the combustion superheater 20 through a certain steam supply path 11, and the steam of 6 MPa superheated to about 500 ° C. by the combustion superheater 20 is supplied to the steam turbine 10, and the generator G is driven to generate electric power. . The steam turbine 1
The steam supplied to the fuel cell 0 and used for power generation is cooled by the condensate cooler 12 through the exhaust steam path 19, collected, and returned to the condensate path 16 circulated to the waste heat boiler 6. A part of the steam supplied to the steam turbine 10 is taken out from the high-pressure side extraction passage 17 and the low-pressure side extraction passage 18 after a part of the energy is supplied to the power generation,
The water is supplied to a water supply preheater 13 provided in the condensate passage 16.

A pressure reducing mechanism 14a using a pressure reducing valve for providing a branch 14 in the steam supply path 11 and reducing a part of the steam generated in the waste heat boiler 6 to about 4 MPa in the branch 14; An accumulator A for accumulating reduced-pressure steam is provided, and an air passage 15 through which the steam from the accumulator A is ventilated is connected to a high-pressure side extraction passage 17 of the turbine 10.

In the waste heat boiler 6, not only does the steam amount of several percent fluctuate frequently in a cycle of several seconds, but also,
When the incineration condition in the incinerator 1 is good (flammable garbage is stably supplied), the amount of steam generated in the waste heat boiler 6 increases as a whole, and the incineration condition deteriorates (moisture content). (A large amount of unburnable refuse is supplied), the steam amount generated in the waste heat boiler 6 is reduced as a whole, and the steam amount fluctuates by several tens of percent in a cycle of tens of minutes. Therefore, when surplus steam is generated in response to a change in steam amount of several tens percent due to a period of tens of minutes, the flow control valve 11 provided in the steam supply path 11 is used.
a is adjusted to accumulate surplus steam in the accumulator A. On the other hand, when the steam generated in the waste heat boiler 6 runs short, the accumulation of steam in the accumulator A is stopped.
The amount of heat supplied to the turbine 10 is effectively used for power generation by squeezing a bleed air amount adjustment valve 17a provided in the high pressure side bleed passage 17 of the turbine 10, and the air flow amount adjustment valve 15a provided in the air passage 15 is opened. And the accumulator A
The steam accumulated in the air is further reduced in pressure (about 2 MPa) and supplied to the high-pressure side extraction passage 17.

The combustion type superheater 20 includes a gas burner 22
The steam from the waste heat boiler 6 passing through the steam flow path is superheated in the superheat path 25 by the heat energy generated by the combustion of the fuel gas supplied from the heater, and the internal side wall of the combustion type superheater 20 is abnormal. A part of its own exhaust gas is circulated through the cooling flow rate control damper 21a and the cooling circulation path 21 as a wall cooling gas for cooling to protect it from damage due to high temperature. This cooling gas is also used as a cooling gas for cooling the combustion gas. still,
The steam heating pipe of the superheating section is constituted by a carbon steel pipe for a boiler.

More specifically, as shown in FIG. 1, a combustion section provided with a gas burner 22, a combustion chamber 23 for burning fuel gas supplied from the gas burner 22, and the exhaust gas burned in the combustion section cause the waste gas to be discharged. A heat exchange section provided with a superheat path 25 for superheating steam from the heat boiler 6, and a part of exhaust gas discharged from the heat exchange section as a cooling gas through the flow control valve 21 a. Combustion chamber 23
And a combustion gas supply path 30 for supplying other exhaust gas as a secondary combustion gas in the incineration path.

The combustion chamber 23 has a peripheral wall and a fuel supply side wall lined with a refractory, and a regular hexagonal plate-like refractory is combined with a combustion gas diffusion mechanism 24 having a regular hexagonal through hole. The main combustion chamber 23a in which the fuel gas supplied from the gas burner 22 burns, and the combustion gas burned in the main combustion chamber 23a is cooled when passing through the through hole of the diffusion mechanism 24. And a post-combustion chamber 23b which is agitated and mixed with the working gas to perform post-combustion. And
In the vicinity of the peripheral wall around the gas burner 22, there are provided 12 front nozzles for blowing and supplying cooling combustion exhaust gas from the exhaust gas circulation path 21 along the peripheral wall.
It is connected to the exhaust gas circulation path 21. In this way, the cooling gas forms a cooling gas flow layer along the peripheral wall of the main combustion chamber 23a, and cools the peripheral wall, and at the same time, avoids the combustion gas from directly contacting the peripheral wall. They are protected from overheating. The cooling gas is mixed with the combustion gas at the outlet of the main combustion chamber 23a to dilute and cool the combustion gas.

Eight side nozzles are provided in the peripheral wall in the vicinity of the diffusion mechanism 24 in the circumferential direction toward the inside of the main combustion chamber 23a, and the diffusion exhaust gas passage branched from the exhaust gas circulation passage 21 is provided. Reference numeral 28 is connected to each of the side nozzles via a flow control valve 28a. The gas burner 22
When the excess air coefficient of the air supplied to the side nozzles is low, the cooling gas forming a gas flow layer is blown inward along the peripheral wall by the exhaust gas for diffusion blown from these side nozzles, and the combustion gas is burned. While mixing and diffusing with the gas, it passes through the through-hole of the diffusion mechanism 24 and
b, and is burned after contact with the residual oxygen in the combustion gas and the oxygen in the circulating exhaust gas as the temperature decreases.

Further, a flow meter 21b for detecting the flow rate of the cooling gas is provided downstream of the branch point of the exhaust gas path 28 for diffusion in the exhaust gas circulation path 21. A flow meter 28b is provided. Further, a superheater inlet steam flow rate detecting means 32 for detecting a steam supply amount from the waste heat boiler 6 is provided at an inlet of the superheat path 25, and a temperature reduction mechanism 25a is provided in the middle of the superheat path 25 and at a subsequent stage. In the preceding stage, a water supply mechanism 25b is provided respectively, and a superheated steam detection means 33 is provided at the outlet thereof.

If there is a shortage in the steam amount based on the detection result of the inlet steam flow detecting means 32, water is supplied to the water supply mechanism 25b through the pre-stage water spray amount control valve, and the water is supplied to the steam turbine 10. At the same time that shortage of supplied superheated steam is not caused, and when it is detected from the detection result of the superheated steam detection means 33 that the superheated steam temperature becomes too high, the temperature of the superheated steam is controlled via the temperature control mechanism water spray amount control valve. Thus, water is supplied to the temperature reducing mechanism 25a to prevent excessive overheating of the superheated steam supplied to the steam turbine 10. Further, based on the flow rate detection result of the superheated steam detection means 33, the gas burner 2
The fuel supply amount is controlled by the fuel adjustment means 22a provided in the fuel supply path to the fuel gas supply line 2, and the excess air coefficient is maintained by the air adjustment means 22b provided in the air supply path to the gas burner 22 according to the fuel supply amount. It is like that. The fuel supply amount is adjusted by proportional control on the opening of the pre-stage water spray amount control valve and the desuperheated water spray amount control valve, and by PID control on the superheated steam temperature.

A combustion gas temperature detecting means 27 for detecting a temperature of the combustion gas at the outlet of the combustion chamber 23 is provided in a flow path of the combustion gas to the superheating path 25, and protects a steam heating pipe constituting a heating section. For this purpose, the supply amount of the exhaust gas for diffusion is adjusted by the flow control valve 28a, and the temperature detected by the detection means 27 is maintained at 900 ° C. or lower. If the temperature of the superheated steam at the outlet of the superheat path 25 is maintained at 500 ° C. while adjusting as described above, the tube wall temperature of the steam heating tube can be suppressed to about 530 ° C. Therefore, it is not necessary to use a special high-temperature material for the steam superheater. At the exhaust gas outlet of the combustion type superheater 20, exhaust gas detecting means 26 for detecting exhaust gas is provided, and the flow rate is set so that the temperature detected by a thermometer 26a included in the exhaust gas detecting means 26 approaches 400 ° C. The control valve 21a is adjusted within a range where the combustion gas temperature can be maintained at approximately 900 ° C. Further, the exhaust gas detecting means 26 is also provided with a component meter 26b for detecting the oxygen concentration in the combustion exhaust gas, and based on the detection result of the component meter 26b, the gas regulating means 22b is used by the air regulating means 22b to optimize the combustion. Adjust the air supply to the system.

In order to optimize each flow rate control described above, a control means C for controlling the controls of the adjusting means 22a and 22b and the valves 21a and 28a is provided. Further, a first exhaust gas supply passage 30a for supplying high-temperature exhaust gas from the combustion type superheater 20 to a secondary combustion region of the incinerator 1
And a second exhaust gas supply path 30b for supplying the secondary combustion area via an air preheater 29 for heating the combustion air to the combustion type superheater 20, and an exhaust gas flow rate adjusting means 31.

In the following, a computer for controlling the target steam flow to be generated by the waste heat boiler 6 as Q and the target temperature of the steam output from the combustion type superheater 20 as T is used. The operation of the control means C is shown in FIG.
This will be described in detail based on the flowchart shown in FIG. The steam flow rate X is measured by the flow rate sensor 32 provided at the steam input section of the combustion type superheater 20 <# 1>, and the steam fluctuation amount ΔQ = X−
Q is calculated, and the subsequent step is selected based on the steam fluctuation amount ΔQ <# 2>. If the steam fluctuation amount ΔQ is negative, the water supply mechanism 25b adjusts the opening of the pre-stage water spray amount control valve (not shown in FIG. 1) to increase and control the steam amount <# 3>. The opening degree of the fuel supply control valve as the fuel adjusting means 22a is adjusted in conjunction with the opening degree adjustment of the preceding-stage water spray amount control valve. <# 4> Subsequently, the process proceeds to step <# 5>. If the steam fluctuation amount ΔQ is 0, that is, if the target value is not satisfied, the process proceeds to step <# 8> described later. Steam fluctuation Δ
If Q is positive, the process proceeds to step <# 5> without changing the fuel supply amount. For example, when the steam fluctuation amount ΔQ is positive, the valve 15a is closed, and the pressure reducing valve 14a is opened to store excess steam in the accumulator A. When the steam fluctuation amount ΔQ is negative, water is sprayed and then overheated. The amount of fuel supply is increased by increasing the opening of the two control valves 22a and 22b in order to increase the required amount of heat. In addition, the detected temperature Tg from the combustion gas temperature detecting means 27 is compared with a set combustion gas temperature Ts (900 ° C. in this example), and is compared with <# 6>,
The opening degree of the flow control valve 21a is adjusted by feedback control <# 7>. It is to be noted that the temperature of the peripheral wall of the combustion chamber 23 is prevented from being abnormally high due to being heated by the combustion gas (for example, 1600 ° C.) from the circulating exhaust gas amount adjusted in the step <# 7> (in this example, 1200 ° C
A temperature controller (not shown) for detecting the peripheral wall temperature is provided so as to supply the cooling gas for suppressing the temperature through the front nozzle, and the flow rate is controlled by the flow rate control valve 28a. . Here, flow meters 21b and 28b are provided in both exhaust gas flow paths,
The detection results of b and 28b are fed back to adjust the opening of the two flow control valves 21a and 28a. The superheated steam temperature Y was measured by a superheated steam temperature detector 33 provided at the outlet of the combustion type superheater 20 <# 8>, and the temperature difference Δ
T = Y−T is calculated, and the transition step is selected based on the temperature difference ΔT <# 9>. That is, if the temperature difference ΔT is 0, the process proceeds to step <# 12>. Temperature difference Δ
If T is positive, the degree of opening of the temperature control mechanism water spray amount control valve (not shown in FIG. 1) in the temperature reduction mechanism 25a is adjusted based on the result of the water spray amount calculation <# 10>. <# 11> after the steam temperature is lowered to the target steam temperature T by <1>, the process proceeds to step <# 12>. If the temperature difference ΔT is negative, the flow returns to step <# 4>, and the amount of fuel to be supplied to the gas burner 22 and the amount of combustion air are again adjusted to increase.
5> The subsequent operations are repeated. Further, the oxygen concentration in the combustion exhaust gas is measured by a component meter 26b provided in the exhaust gas detecting means 26 <# 12>, and a target value (for example, 1.1) calculated from an air excess coefficient (for example, 1.1) in the gas burner 22 is set in advance. For example, it is compared with a dry base oxygen concentration of 2.10% <# 13>. As a result, if the measured oxygen concentration (for example, a dry base converted value) is within a range that can be satisfied with respect to the target value, the step <#
1>, and repeat the above-mentioned control of step <# 1> and the subsequent steps to repeat the above-mentioned measured oxygen concentration (for example, a dry base converted value).
Is out of the range that can be satisfied with respect to the target value, the opening degree of the air control valve 22b is adjusted according to the deviation, and the process returns to the step <# 1>, and returns to the step <# 1>.
# 1> The following control is repeated. That is, when the measured oxygen concentration exceeds the target value, the opening degree of the air control valve 22b is reduced, the air supply amount is slightly reduced, and the excess air rate is substantially reduced. If the concentration does not reach the target value, the degree of opening of the air control valve 22b is increased to slightly increase the air supply <# 14>. The opening adjustment amount of the air control valve 22b is calculated based on the degree of deviation of the measured oxygen concentration from the target value.

That is, based on the detection values from the exhaust gas detecting means 26 and the combustion gas temperature detecting means 27, the flow control valve 21 in the exhaust gas circulating path 21 is controlled by the control means C.
a, controlling the combustion exhaust gas temperature by adjusting the supply amount of the circulating exhaust gas by adjusting the flow control valve 28a of the diffusion exhaust gas passage 28, and simultaneously adjusting the supply amounts of the fuel and air to the gas burner 22 by controlling the combustion type. The exhaust gas loss from the superheater 20 is kept constant, and the exhaust gas loss is minimized. Since the exhaust gas loss depends on the exhaust gas temperature and the exhaust gas amount, and the latter greatly depends on the excess air coefficient, the exhaust gas temperature is controlled so as to suppress the exhaust gas temperature and to minimize the air supply amount.

Further, the control means C calculates the steam fluctuation amount Δ
If Q is negative, it is determined that the combustion state of the incinerator 1 has decreased, and the combustion type superheater of the combustion exhaust gas with a low residual oxygen concentration (about 2-3%) from the combustion type superheater 20 20
The surplus for the circulating supply to the first exhaust gas supply path 3
By adjusting the exhaust gas flow rate adjusting means 31 so as to supply the exhaust gas to the secondary combustion area of the incinerator 1, a high temperature exhaust gas of about 300 ° C. is supplied as a stirring gas. Conversely, if the steam fluctuation amount ΔQ is positive or zero, it is determined that the combustion state of the incinerator 1 is good, and the exhaust gas energy is reduced to reduce the fuel consumed by the combustion superheater 20. The exhaust gas from the combustion type superheater 20 is supplied to the second exhaust gas supply passage 30b by adjusting the exhaust gas flow rate adjusting means 31 for use.
The exhaust gas that has passed through 9 and has dropped to about 150 ° C. is supplied to the secondary combustion zone of the incinerator 1 as a gas for stirring. That is, the control means C also controls the recovery of the waste heat of the combustion type superheater 20. The control means C controls not only the combustion exhaust gas circulation system of the combustion type superheater 20 but also the exhaust gas flow control. It is configured as a control means for optimizing the operation of the refuse incinerator including the control of the means 31.

Next, another embodiment of the present invention will be described. <1> In the above-described embodiment, an example has been described in which the diffusion mechanism 24 is provided in the combustion chamber 23 and divided into the main combustion chamber 23a and the post-combustion chamber 23b. The combustion chamber 23 may be provided solely for uniformity, and may be configured as a single unit and disposed at the outlet thereof. In this case, the combustion gas may be agitated by supplying the exhaust gas for diffusion. <2> The diffusion mechanism 24 may be omitted. In this case, the supply of the exhaust gas for diffusion may contribute to agitation of the combustion gas and uniformization of its temperature. <3> The exhaust gas passage for diffusion 28 may be omitted, and the exhaust gas for cooling and the combustion gas may be mixed and diffused only by the diffusion mechanism 24 to make the temperature of the combustion gas uniform. Further, in controlling the outlet temperature of the combustion chamber 23, only the flow rate of the circulating exhaust gas as the cooling gas may be adjusted. The temperature of the combustion chamber 23 outlet was 9
The temperature was set to 00 ° C. for the superheat path 25 made of carbon steel tubes for boilers.
To prevent heat damage, and also because the bleeding steam turbine is used in the power generation device, the steam superheat temperature may be 500 ° C., and both the combustion chamber outlet temperature and the steam superheat temperature The temperature is not limited to the above-mentioned temperature, and should be appropriately set according to the configuration of the refuse incinerator. In addition, even when the reheat steam turbine is used in the power generation device, the steam superheat temperature of 500 ° C. is sufficient. <4> An example is shown in which 12 front nozzles are provided to supply circulating exhaust gas from the exhaust gas circulation path 21 to the combustion chamber 23 so as to blow them along the peripheral wall of the main combustion chamber 23a. It is optional, and the installation position and direction are also optional. For example, a front nozzle may be provided to penetrate the peripheral wall. In this case, a guide for guiding the exhaust gas supplied from the front nozzle along the peripheral wall may be provided. <5> The diffusion exhaust gas path 28 may be provided facing the downstream side of the diffusion mechanism 24, and the number of the side nozzles is arbitrary. Also, the blowing direction of the exhaust gas for diffusion may be directed inward as shown in the above embodiment, and may be provided to be inclined forward of the combustion chamber 23. With such an arrangement, a motion direction component against the flow of the combustion gas is generated, so that the effect of stirring the combustion gas is increased. <6> Although the exhaust gas detecting means 26 is shown as comprising a thermometer and a component meter, the component meter is not limited to oxygen concentration detection, and may be, for example, a device for detecting carbon monoxide concentration. Alternatively, a plurality of oxygen / carbon dioxide / carbon monoxide gases may be detected. If a plurality of components are detected, the combustion state can be grasped more accurately. <7> The operation of the control unit C described in the above embodiment is an example, and the operation is not limited to the above example. In other words, the control means C may simply supplement the operation of the instrumentation device of the combustion type superheater. For example, it may simply supplement the control relating to the excess air coefficient. For example, the control valve 21 may
1, the control valve 28a performs feedback control based on the flow rate of the diffusion exhaust gas passage 28, and the air control valve 22b performs proportional control with the fuel control valve 22a. Control means for setting may be used. This control means C may set only the reference value of the feedback control of the exhaust gas circulation amount, as long as it can control at least the combustion gas temperature at the outlet of the combustion chamber 23, and further as described above. The control means may be constituted only by a group of automatic controllers. <8> The thermometer 26 provided in the exhaust gas detecting means 26
The exhaust gas temperature may be measured by a, and the opening degree of the flow control valve 21a may be finely adjusted according to the difference from the target exhaust gas temperature (for example, about 300 ° C.). That is, if the exhaust gas temperature is higher than the target exhaust gas temperature, the opening of the flow rate control valve 21a is somewhat reduced, and if the exhaust gas temperature is lower than the target exhaust gas temperature, the opening of the flow rate control valve 21a is slightly increased. The exhaust gas temperature may be adjusted while maintaining the combustor outlet temperature. <9> The arrangement of the flow control valve 21a is not limited to the position shown in FIG. 1 and may be arranged downstream of a branch point with the exhaust gas passage 28 for diffusion, and is arranged at a position where the exhaust gas circulation amount can be adjusted. It would be fine. For example, in the case where the exhaust gas circulation passage for diffusion 28 is provided, it is sufficient that the combustion exhaust gas circulated and supplied to the combustion chamber 23 can be adjusted. preferable. <10> It is a preferred embodiment that the air to the gas burner 22 is preheated air, and air at normal temperature may be supplied. Further, it is a preferred embodiment that the combustor 22 is a gas burner, and the burner 22 is not limited to this, and may be a burner that burns a liquid fuel such as a heavy oil burner or a light oil burner. An external combustion type combustion facility that burns and introduces the combustion gas into the superheat path may be used. In short, the combustor according to the present invention is one that supplies a high-temperature gas to a superheat path, and may be a gas introduction path that introduces a high-temperature gas. <11> The operation of the control means C described above is a preferable example, and the acquisition position / time / content of the measurement value, the control priority, the step shift options, the selection conditions thereof, and the like are determined by the refuse incineration apparatus. It can be changed as appropriate depending on the configuration, and it may be configured by a plurality of control means, and may be configured to be controlled independently or in connection with each other. <12> The combustion gas temperature detecting means 27 provided in the combustion type superheater 20 described in the above embodiment is not
5, the temperature detecting means 27 may be located at any position capable of detecting the temperature of the combustion gas. For example, the temperature detecting means 27 may be provided at the outlet of the combustion chamber 23 or in the vicinity thereof. There may be.

[0027]

[Example 2]

(B) Fuel supply amount 1.73 Nm3 / h [1 hour cumulative measured amount] (g) Air supply amount 22.83 Nm3 / h [1 hour cumulative measured amount] (Air excess coefficient 1.20) (s) Superheater outlet Gas amount 52.16 Nm3 / h [1 hour cumulative measured amount] (C) Exhaust gas circulation amount 27.60 Nm3 / h [(S)-(SO)] (SO) Exhaust gas amount 24.56 Nm3 / h [1 hour cumulative measured amount (T) Heat input 17196 Kcal / h [Calculated value (S) x 9940] (H) Exhaust gas temperature 151 ° C [Average measured over 1 hour] (T) Calculated exhaust gas loss heat 1222 Kcal / h [(S) x (H) × 0.3295] (T) Exhaust gas loss 7.1% [(T) × 100 / (T)] [Comparative example] (D) Fuel supply amount 1.73 Nm3 / h [Hourly cumulative measurement amount] (D) Air supply Amount 50.43 Nm3 / h [1 hour cumulative measured amount] (Air excess coefficient 2.65) (N) Superheater outlet gas amount 52.16 Nm3 / h [1 hour cumulative measured amount] (D) Exhaust gas circulation amount 0 00Nm3 / h [(nu)-(no)] (no) Exhaust gas amount 52.16 Nm3 / h [1 hour cumulative measurement amount] (c) Heat input amount 17196 Kcal / h [calculated value (te) x 9940] (e) Exhaust gas Temperature 150 ° C [1 hour average] (F) Calculated heat loss of exhaust gas 2578 Kcal / h [(NO) x (HI) x 0.3295] (F) Exhaust gas loss 15.0% [(HI) x 100 / (HI) As described above, it is clear that the waste gas loss decreases with the increase in the amount of waste gas circulation for the same fuel supply amount, but the increase in the amount of waste gas circulation also increases. As a result, the gas flow rate at the superheater outlet also increased, and as a result, the gas temperature at the combustor outlet was constant, so the amount of heat supplied to the superheat path increased. Since the efficiency was also improved, a generator output that could be judged to be able to increase the supplied superheated steam amount was obtained. The heat efficiency of the heater was 87%, which could be measured with a small combustion heater at the demonstration plant.

[0028]

As described above, according to the present invention,
The controllability of the combustion type superheater in the garbage incinerator can be improved, and at the same time, the exhaust gas loss can be reduced, and at the same time the fuel consumption can be reduced.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a main part showing an example of a garbage incinerator according to the present invention.

FIG. 2 is an explanatory view showing an example of a garbage incinerator according to the present invention.

FIG. 3 is a flowchart.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incinerator 3 Power generator 6 Waste heat boiler 10 Steam turbine 11 Steam supply path 20 Combustion type superheater 21 Exhaust gas circulation path 22 Combustor 23 Combustion chamber 23a Main combustion chamber 23b Rear combustion chamber 24 Combustion gas diffusion mechanism 25 Steam superheat path 26 Exhaust gas detecting means 27 Combustion gas temperature detecting means 28 Diffusion exhaust gas path

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-174202 (JP, A) JP-A-6-193805 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23G 5/46 ZAB F23G 5/50 ZAB F22B 1/18 F22G 1/16 F22G 5/02-5/04

Claims (5)

(57) [Claims] A waste heat boiler (6) for recovering waste heat from exhaust gas generated in an incinerator (1) to generate steam and a power generator (3) for driving a turbine (10) with the generated steam to generate power. And a refuse incinerator provided with a combustion type superheater (20) for superheating steam in a steam supply path (11) from the waste heat boiler (6) to the power generator (3). Te, the combustion superheater the flue gas from (20) fired superheater exhaust gas circulation path for introducing (20) of the combustion chamber (23) (21) is provided, the combustion chamber (23) main combustion Chamber (23a) and post combustion chamber
(23b) and the main combustion chamber (23a) and the after-combustion chamber (23b).
A combustion gas diffusion mechanism (24) is provided between the main combustion chamber (23a) and the exhaust gas circulation path.
After mixing and diffusing the circulating exhaust gas from (21),
Garbage burning with post combustion in the combustion chamber (23b)
Device. 2. A refuse incineration apparatus according to claim 1, further comprising a diffusion exhaust gas passage provided with the circulation exhaust gas supply section inward near the combustion gas diffusion mechanism. 3. Waste heat from exhaust gas generated in the incinerator (1)
Waste heat boiler (6) that collects and generates steam, and its generation
A power generation device that generates power by driving a turbine (10) with steam
(3) and the power generation from the waste heat boiler (6).
Superheat the steam in the steam supply passage (11) to the device (3)
Garbage incinerator equipped with a combustion type superheater (20)
I, the combustion flue gas from the combustion superheater (20)
Exhaust gas introduced into the combustion chamber (23) of the superheater (20)
An annular path (21) is provided, and the combustion chamber (23) is divided into a main combustion chamber (23a) and a post-combustion chamber.
(23b) and the main combustion chamber (23a) and the after-combustion chamber (23b).
In the meantime, the circulation exhaust gas is directed toward the inside of the combustion chamber (23).
A diffusion exhaust gas path (28) provided with a gas supply section, and a combustion gas in the main combustion chamber (23a) and the exhaust gas circulation path.
After mixing and diffusing the circulating exhaust gas from (21),
Garbage burning with post combustion in the combustion chamber (23b)
Device. 4. A combustion gas temperature detecting means (27) is provided downstream of the combustion chamber (23), and the combustion gas temperature from the exhaust gas circulation path (21) is determined based on the detection result of the combustion gas temperature detecting means (27). An exhaust gas circulation amount adjusting means for adjusting the circulation amount of the circulation exhaust gas, and a control means (C) capable of adjusting the temperature of the combustion gas from the after-combustion chamber (23b) introduced into the steam superheating path (25). The refuse incineration device according to claim 1. 5. The combustor (2) of the combustion type superheater (20) based on the detection result of the oxygen content in the combustion exhaust gas from an exhaust gas detection means (26) provided in the combustion type superheater (20).
The refuse incinerator according to any one of claims 1 to 4, wherein the control means (C) is provided with an adjusting means for adjusting an air supply amount to 2).