JP6804371B2 - How to operate a waste treatment plant and a waste treatment plant - Google Patents

Description

The present invention relates to a waste treatment plant including an incinerator for burning waste and an operation method thereof.

Conventionally, a stoker type incinerator that incinerates waste as waste is known (see, for example, Patent Document 1).
In an incinerator that incinerates waste, it is difficult to stably supply a fixed amount of municipal waste and the like. In addition, when waste of varying quality is burned in an incinerator, the amount of heat generated in the incinerator changes due to changes in the amount of combustion gas generated, the amount of combustion air, the amount of fuel supplied, and the like. When the amount of heat generated in the incinerator changes, the flow rate of steam generated in the incinerator also changes accordingly. In particular, when low-quality waste with a large amount of water is thrown in as waste, the temperature inside the incinerator drops due to the removal of heat from the surroundings when the water evaporates, and the steam generated in the incinerator accordingly. The flow rate of is also reduced.

In such a case, the worker had to judge whether the waste was low quality from the flow rate of steam generated in the incinerator, wait for the low quality waste to burn, and then restart the supply of the waste. .. Therefore, the incinerator lacks the smooth operation, and it takes time to stabilize the operating conditions thereafter. Further, since it is left to the operator to judge whether or not the waste is low quality, there is a problem that the reliability is lowered due to individual differences and the flow rate of steam is not stable.
Patent Document 1 corrects the supply amount of the primary combustion air to the increase side and corrects the target value of the heating temperature of the primary combustion air to the high temperature side when the dust supply efficiency indicating the waste supply amount increases. This is to avoid a decrease in the amount of combustion when condensed and low-breathable waste is supplied.

Japanese Unexamined Patent Publication No. 2004-245517

However, in Patent Document 1, in order to keep the combustion amount constant, the correction factor of the supply amount of the primary combustion air and the correction factor of the heating temperature of the primary air with respect to the dust supply efficiency of the waste are accurately set in advance. It is necessary and requires a lot of design man-hours. In addition, since it is difficult to uniquely identify the properties of waste, even if the correction factor for the supply amount of primary combustion air and the correction factor for the heating temperature of primary air are set in advance, the combustion amount should be kept constant. It is difficult. Therefore, in Patent Document 1, when the amount of heat generated in the incinerator fluctuates due to a change in the properties of waste or the like, the output of the steam turbine and the amount of power generated by the generator fluctuate accordingly.

The present invention has been made in view of such circumstances, and maintains a constant output of the steam turbine even when the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste or the like. It is an object of the present invention to provide a waste treatment plant capable of producing and a method of operating the waste treatment plant.

In order to solve the above problems, the present invention employs the following means.
The waste treatment plant according to one aspect of the present invention is used as power in an incinerator that burns waste to generate steam, a steam turbine driven by the steam generated by the incinerator, and the steam turbine. The targets are a heater that heats the steam, an internal combustion engine that burns fuel to generate driving force, an introduction flow path that guides exhaust gas discharged from the internal combustion engine to the heater, and an output of the steam turbine. A control unit for controlling the amount of heat of the exhaust gas guided from the introduction flow path to the heater so as to be an output is provided.

According to the waste treatment plant according to one aspect of the present invention, the control unit controls the amount of heat of the exhaust gas guided from the introduction flow path to the heater so that the output of the steam turbine becomes the target output. Therefore, even if the amount of heat generated in the incinerator fluctuates due to changes in the properties of garbage and the amount of heat of steam generated in the incinerator fluctuates accordingly, the exhaust gas discharged from the internal combustion engine causes the steam turbine. Is adjusted so that the output of is the target output. Therefore, even when the amount of heat generated in the incinerator fluctuates due to changes in the properties of dust or the like, the output of the steam turbine can be maintained constant.

In the waste treatment plant according to one aspect of the present invention, the control unit may control the output of the internal combustion engine so that the amount of heat of the exhaust gas guided from the introduction flow path to the heater is adjusted.
By controlling the output of the internal combustion engine so that the output of the steam turbine becomes the target output, the output of the steam turbine even when the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste, etc. Can be maintained constant.

The waste treatment plant according to one aspect of the present invention is provided with an introduction adjusting valve which is arranged in the introduction flow path and adjusts the flow rate of the exhaust gas guided to the heater, and the control unit is the introduction flow path. The opening degree of the introduction adjusting valve may be controlled so that the flow rate of the exhaust gas guided from the heater to the heater is adjusted.
When the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste, etc., by adjusting the flow rate of the exhaust gas guided from the introduction flow path to the heater so that the output of the steam turbine becomes the target output. Even if there is, it is possible to maintain the output of the steam turbine constant.

In the waste treatment plant having the above configuration, the steam turbine includes a high-pressure turbine to which the steam generated by the incinerator is supplied and a low-pressure turbine to which the steam discharged from the high-pressure turbine is supplied. the heater, the steam reheater der to heat the steam exhausted from the high pressure turbine is, the flow rate of the flow rate measured value the steam of the steam supplied to the low-pressure turbine from the steam reheater The calorific value of the exhaust gas guided from the introduction flow path to the steam reheater may be controlled so as to compensate for the insufficient flow rate of the steam supplied to the low-pressure turbine when the value is lower than the target value .
By doing so, the steam whose temperature has dropped due to work in the high-pressure turbine is reheated by the steam reheater using the exhaust gas of the internal combustion engine as a heat source, and then supplied to the low-pressure turbine. Then, steam is supplied from the introduction flow path so as to compensate for the insufficient flow rate of the steam supplied to the low pressure turbine when the measured flow rate of the steam supplied from the steam reheater to the low pressure turbine is lower than the target value of the steam flow rate. The amount of heat of the exhaust gas guided to the reheater is controlled.

In the waste treatment plant according to one aspect of the present invention, the internal combustion engine may include a high-pressure turbine and a turbine generator that generates electricity by a driving force transmitted from the low-pressure turbine .
By doing so, steam is generated by the heat generated by the combustion of the waste, and the energy of the steam can be recovered as electric power by the turbine generator. In addition, by controlling the output of the internal combustion engine so that the output of the high-pressure turbine and the steam turbine having the low-pressure turbine becomes the target output, the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste and the like. However, it is possible to maintain a constant power output of the turbine generator.

The waste treatment plant according to one aspect of the present invention may include an internal combustion engine generator that generates electricity by the driving force transmitted from the internal combustion engine.
By doing so, the driving force generated by the combustion of fuel in the internal combustion engine can be recovered as electric power by the internal combustion engine generator.

In the waste treatment plant according to one aspect of the present invention, the internal combustion engine may be a gas engine driven by methane-containing biogas generated from the waste.
Since the methane-containing biogas generated from the waste can be used as fuel for a gas engine which is an internal combustion engine, it is not necessary to use a separate fuel other than waste as fuel for the internal combustion engine. Therefore, the manufacturing cost and the operating cost of the waste treatment plant can be reduced.

The operating method according to one aspect of the present invention includes an incinerator that burns waste to generate steam, a high-pressure turbine to which the steam generated by the incinerator is supplied, and the steam discharged from the high-pressure turbine. A low-pressure turbine to which is supplied, a steam reheater that heats the steam discharged from the high-pressure turbine and supplies it to the low-pressure turbine, an internal combustion engine that burns fuel to generate driving force, and the internal combustion engine. A method of operating a waste treatment plant including an introduction flow path for guiding the exhaust gas discharged from the steam reheater to the steam reheater , and a measured flow rate value of the steam supplied from the steam reheater to the low pressure turbine. a measuring step of measuring, said measuring step such that supplement the flow shortage of the steam which the flow rate measured value measured is supplied to the low-pressure turbine is lower than the target flow rate value of said vapor, said inlet flow A control step for controlling the amount of heat of the exhaust gas guided from the path to the steam reheater is provided.

In the operation method of the waste treatment plant according to one aspect of the present invention, the control step is from the introduction flow path to the heater so that the output of the steam turbine is detected and the detected output of the steam turbine becomes the target output. Controls the amount of heat of the induced exhaust gas. Therefore, even if the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste and the amount of heat of steam generated in the incinerator fluctuates accordingly, the exhaust gas discharged from the internal combustion engine causes the steam turbine. Is adjusted so that the output of is the target output. Therefore, even when the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste or the like, the output of the steam turbine can be maintained constant.

According to the present invention, a waste treatment plant capable of maintaining a constant output of a steam turbine and an operation method thereof even when the amount of heat generated in the incinerator fluctuates due to changes in the properties of waste or the like. Can be provided.

It is a schematic block diagram which shows the waste power generation plant which concerns on 1st Embodiment of this invention. It is the schematic sectional drawing of the incinerator shown in FIG. It is a control block diagram which shows the operation performed by the control apparatus of 1st Embodiment. It is a schematic block diagram which shows the waste power generation plant which concerns on 2nd Embodiment of this invention. It is a control block diagram which shows the operation performed by the control apparatus of 2nd Embodiment. It is a control block diagram which shows the operation performed by the control apparatus of 3rd Embodiment.

[First Embodiment]
The waste power generation plant (waste treatment plant) 1 according to the first embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the waste power plant 1 according to the present embodiment is driven by an incinerator 3 that generates steam by combustion gas generated by burning waste and steam from the incinerator 3. A steam turbine 4, a methane fermenter 5 that generates methane-containing biogas from waste, a gas engine (internal engine) 6 that burns methane-containing biogas from the methane fermenter 5 to generate driving force, and waste. It is provided with a control device 50 that controls the entire physical power plant 1.

Here, the waste is, for example, household waste, and includes solid waste made of paper, plastic, etc., and kitchen waste made of biomass such as leaves and branches. The waste is separated into solid waste to be burned in the incinerator 3 and kitchen waste to be supplied to the methane fermenter 5.

Further, the waste power generation plant 1 is generating power by a first generator (turbine generator) 7 and a second generator (internal engine generator) 8. The rotating shaft of the first generator 7 is connected to the rotating shaft of the steam turbine 4. The first generator 7 generates electricity by the driving force transmitted from the steam turbine 4. Further, the rotating shaft of the second generator 8 is connected to the rotating shaft of the gas engine 6. The second generator 8 generates electricity by the driving force transmitted from the gas engine 6.

The electric power generated by the first generator 7 is supplied to, for example, an electric power system (not shown). The electric power generated by the second generator 8 is used, for example, as power for each facility of the waste power generation plant 1.

The incinerator 3 separates the waste stored in the waste pit 14 and burns the solid waste supplied from the waste supply channel 12 by the combustion air introduced from the combustion air introduction pipe 13.
The incinerator 3 is, for example, the stoker type incinerator shown in FIG. 2, from the charging hopper 3A that receives the waste D, the feeder 3I that supplies the waste D charged into the charging hopper 3A into the furnace, and the feeder 3I. The stalker 3B that transfers the supplied waste D, the primary air supply unit 3C that supplies the primary air from below the stalker 3B, the incinerator body 3D that burns the waste D transferred by the stalker 3B, and the incinerator body. A boiler 3E that generates water vapor from combustion exhaust gas discharged from 3D, a secondary air supply unit 3F that supplies secondary air to the incinerator main body 3D, and a start-up burner 3G that is used when starting the incinerator 3. A temperature sensor 3H for measuring the temperature inside the incinerator main body 3D is provided.
The feeder 3I supplies the waste D loaded on the plate-shaped member to the stoker 3B by moving the plate-shaped member in the horizontal direction.

A secondary air supply nozzle 3Da and a secondary air supply nozzle 3Db are arranged below the incinerator main body 3D. The secondary air supply nozzle 3Da and the secondary air supply nozzle 3Db input the secondary air supplied from the secondary air supply unit 3F into the incinerator main body 3D. The secondary air supply unit 3F supplies the secondary air blown by the push blower 3F to the secondary air supply nozzle 3Da and the secondary air supply nozzle 3Db at a flow rate adjusted by the secondary air flow rate adjusting valve 3Fb. The secondary air supply unit 3F supplies the air in the atmosphere to the incinerator main body 3D as secondary air during the normal operation of the incinerator 3.

In the present embodiment, the waste supplied to the incinerator 3 is solid waste to be incinerated. The separated waste to be fermented with methane is supplied to the methane fermentation tank 5 via the waste supply channel 15.

The combustion gas generated in the incinerator main body 3D exchanges heat with water flowing through a plurality of heat transfer tubes (not shown) installed in the boiler 3E. The combustion gas that has completed heat exchange with the water supply flowing in the heat transfer tube is discharged from the boiler 3E as combustion exhaust gas. As shown in FIG. 1, the combustion exhaust gas discharged from the boiler 3E circulates in the combustion exhaust gas pipe 17, undergoes necessary treatment in the filtration type dust collector 18, and then is exhausted from the chimney 20 to the atmosphere through the fan 19. Will be done.

The heat transfer tube installed in the boiler 3E has a structure in which the heat transfer tube is folded back a plurality of times in the vicinity of the wall portion of the boiler 3E. Water supply circulates inside the heat transfer tube. The upstream end of the heat transfer pipe communicates with the steam supply pipe 21, and the downstream end communicates with the water supply pipe 22. Steam is generated by heat exchange between the water supply flowing in the heat transfer tube and the combustion gas flowing in the boiler 3E.

As shown in FIG. 1, the steam generated by the boiler 3E flows through the steam supply pipe 21 and is introduced into the high-pressure turbine 4A of the steam turbine 4. The steam introduced into the high-pressure turbine 4A rotates the high-pressure turbine 4A. The high pressure turbine 4A is connected to the low pressure turbine 4B via a rotary shaft 4C. The rotating shaft of the first generator 7 is connected to the low-pressure turbine 4B, and the rotation of the high-pressure turbine 4A and the low-pressure turbine 4B drives the first generator 7 to generate electricity. A part of the steam introduced into the low-pressure turbine 4B is supplied to the feed water heater 26 described later via the bleed steam pipe 23.

The steam obtained by rotating the steam turbine 4 is condensed in the condenser 24 to become water. The water generated by the condenser 24 circulates in the water supply pipe 22 and is supplied as water supply to the heat transfer pipe provided in the boiler 3E of the incinerator 3. A feed water heater 26 is provided in the feed water supply pipe 22. In the feed water heater 26, a part of the steam extracted from the steam turbine 4 heats the feed water supplied from the condenser 24. The water or steam after heating the feed water with the feed water heater 26 is returned to the condenser 24 via the discharge pipe 27.

The separated waste to be fermented with methane is supplied to the methane fermentation tank 5 via the waste supply channel 15. In the methane fermentation tank 5, methane-containing biogas is generated from waste that is subjected to methane fermentation treatment. The generated methane-containing biogas is supplied to the gas engine 6 via the biogas supply pipe 28. Further, the sludge generated when the methane-containing biogas is generated is discharged from the methane fermentation tank 5, circulates in the sludge discharge pipe 29, and is collected by the sludge recovery unit (not shown).

The gas engine 6 is driven by burning methane-containing biogas supplied from the biogas supply pipe 28 together with air supplied from an air supply device (not shown). In the gas engine 6, the driven piston (not shown) is converted into rotary motion by the crankshaft (not shown). The rotating shaft of the second generator 8 is connected to the rotating shaft of the gas engine 6, and the second generator 8 is driven by driving the gas engine 6 to generate electricity.

The waste power generation plant 1 of the present embodiment steams the combustion exhaust gas pipe 30 for a gas engine that guides the combustion exhaust gas discharged from the gas engine 6 to the outside of the waste power generation plant 1 and the combustion exhaust gas discharged from the gas engine 6. The exhaust gas introduction pipe (introduction flow path) 31 leading to the reheater (heater) 40 is provided. A part of the combustion exhaust gas discharged from the gas engine 6 passes through the combustion exhaust gas pipe 30 for the gas engine and is exhausted to the atmosphere from the chimney 20. The other part of the combustion exhaust gas discharged from the gas engine 6 flows through the exhaust gas introduction pipe 31 and is guided to the steam reheater 40. The combustion exhaust gas that has passed through the steam reheater 40 is exhausted from the chimney 20 into the atmosphere.

Further, the exhaust gas exhaust gas pipe 30 for a gas engine is provided with an exhaust gas exhaust heat recovery device (for example, an organic Rankine cycle) 16. The exhaust gas exhaust heat recovery device 16 recovers the heat of the combustion exhaust gas by exchanging heat between the combustion exhaust gas circulating in the combustion exhaust gas pipe 30 for the gas engine and the working fluid flowing in the exhaust gas exhaust heat recovery device 16. ing.

Next, the operation of the control device 50 of the present embodiment to control the output of the steam turbine 4 so as to be the target output will be described with reference to the control block diagram of FIG.
Here, the control device 50 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. As an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized.

As shown in FIG. 3, the control device 50 of the present embodiment includes a lower limit limiter 50A, a correction value calculation unit 50B, and a controller 50C as functional blocks.
In FIG. 3, the SSV indicates the target value of the steam flow rate supplied from the steam reheater 40 to the low pressure turbine 4B, and the SPV indicates the measured value of the steam flow rate supplied from the steam reheater 40 to the low pressure turbine 4B. Further, ESV indicates a set value of the output of the gas engine 6, and EPV indicates an actually measured value of the output of the gas engine 6.

As shown in FIG. 3, the control device 50 inputs to the lower limit limiter 50A a value obtained by subtracting the measured value SPV of the steam flow rate supplied to the low pressure turbine 4B from the target value SSV of the steam flow rate supplied to the low pressure turbine 4B. To do. The measured value SPV of the steam flow rate is measured by a flow meter (not shown) provided in the steam reheater 40. The value input to the lower limit limiter 50A becomes a positive value when the measured value SPV is lower than the target value SSV, and the value input to the lower limit limiter 50A is a negative value when the measured value SPV is higher than the target value SSV. It becomes.
As the target value SSV, the target value of the steam flow rate generated in the incinerator 3 itself may be set, or the lower limit value obtained by subtracting a predetermined value from the target value of the steam flow rate generated in the incinerator 3 is set. May be good.

The lower limit limiter 50A outputs the value to the correction value calculation unit 50B when the input value is a positive value, and calculates the correction value of "0" when the input value is a negative value. Output to unit 50B. That is, when the measured value SPV of the lower limit limiter 50A is lower than the target value SSV and it is necessary to heat the steam supplied from the steam reheater 40 to the low-pressure turbine 4B, a positive value is sent to the correction value calculation unit 50B. Output.
When the combustion exhaust gas discharged from the gas engine 6 is constantly flowing to the steam reheater 40, it is necessary to reduce the steam supplied from the steam reheater 40 to the low pressure turbine 4B without using the lower limit limiter 50A. If there is, a negative value may be output to the correction value calculation unit 50B.

The correction value calculation unit 50B calculates an output correction value ECV for correcting the output of the gas engine 6 based on the value input from the lower limit limiter 50A. The output correction value ECV is added to the set value ESV of the output of the gas engine 6. The value obtained by subtracting the measured value EPV of the output of the gas engine 6 from the value obtained by adding the output correction value ECV and the set value ESV is input to the controller 50C.

The output correction value ECV is added to the set value ESV in order to increase the output of the gas engine 6 to heat the steam when the measured value SPV is lower than the target value SSV. Further, the reason why the measured value EPV of the output of the gas engine 6 is subtracted is to give feedback so that the output of the gas engine becomes a value obtained by correcting the set value ESV with the output correction value ECV. The measured value EPV of the output of the gas engine 6 is obtained, for example, by converting the power generation output of the second generator 8 into the output of the gas engine 6.

The controller 50C generates a control command value for controlling the output of the gas engine 6 according to the input value, and outputs the control command value to the gas engine 6 to be controlled. Here, the control command value is, for example, a command value for adjusting the flow rate of the methane-containing biogas burned by the gas engine 6 and the flow rate of the air used for the combustion. The gas engine 6 controls the output of the gas engine 6 by adjusting the biogas supply amount, the combustion air flow rate, and the like of the gas engine 6 based on the control command value input from the controller 50C.

As described above, the control device 50 of the present embodiment is a gas engine so as to make up for the shortage of the steam flow rate supplied to the low-pressure turbine 4B when the measured value SPV is lower than the target value SSV of the steam flow rate. Increase the output of 6. When the output of the gas engine 6 increases, the flow rate of the combustion exhaust gas led from the gas engine 6 to the steam reheater 40 via the exhaust gas introduction pipe 31 increases. Then, as the flow rate of the combustion exhaust gas increases, the temperature of the steam heated by the steam reheater 40 increases, and the output of the steam turbine 4 and the power generation amount of the first generator 7 increase. As described above, the control device 50 of the present embodiment sets the flow rate of the exhaust gas (the amount of heat given to the steam) led from the exhaust gas introduction pipe 31 to the steam reheater 40 so that the output of the steam turbine 4 becomes the target output. Control.

The operation and effect of the waste power generation plant 1 of the present embodiment described above will be described.
According to the waste power plant 1 of the present embodiment, the control device 50 controls the output of the gas engine 6 so that the output of the steam turbine 4 becomes the target output, and from the exhaust gas introduction pipe 31 to the steam reheater 40. Adjust the flow rate of the guided exhaust gas. Therefore, even if the amount of heat generated in the incinerator 3 fluctuates due to changes in the properties of waste and the flow rate of steam generated in the incinerator 3 fluctuates accordingly, the exhaust gas discharged from the gas engine 6 The output of the steam turbine 4 is adjusted to be the target output by adjusting the flow rate of. Therefore, even when the amount of heat generated in the incinerator 3 fluctuates due to a change in the properties of waste or the like, the output of the steam turbine 4 can be maintained constant.

In the waste power generation plant 1 of the present embodiment, the steam turbine 4 comprises a high-pressure turbine 4A to which the steam generated by the incinerator 3 is supplied and a low-pressure turbine 4B to which the steam discharged from the high-pressure turbine 4A is supplied. Have. The steam whose temperature has dropped due to work in the high-pressure turbine 4A is reheated by the steam reheater 40 using the combustion exhaust gas of the gas engine 6 as a heat source, and then supplied to the low-pressure turbine 4B. Then, the amount of heat of the exhaust gas guided from the exhaust gas introduction pipe 31 to the steam reheater 40 is controlled so that the output of the steam turbine 4 becomes the target output.

The waste power generation plant 1 of the present embodiment includes a first generator 7 that generates electricity by a driving force transmitted from a steam turbine 4. By doing so, steam is generated by the heat generated by the combustion of the waste, and the energy of the steam can be recovered as electric power by the first generator 7. Further, by controlling the output of the gas engine 6 so that the output of the steam turbine 4 becomes the target output, even if the amount of heat generated in the incinerator 3 fluctuates due to a change in the properties of waste or the like, the first It is possible to maintain the power generation output of the generator 7 at a constant level.

The waste power generation plant 1 of the present embodiment includes a second generator 8 that generates electricity by a driving force transmitted from the gas engine 6. By doing so, the driving force generated by the combustion of the fuel in the gas engine 6 can be recovered as electric power in the second generator 8.

In the waste power generation plant 1 of the present embodiment, the gas engine 6 is driven by the methane-containing biogas generated from the waste. Since the methane-containing biogas generated from the waste burned in the incinerator 3 can be used as the fuel for the gas engine 6 which is an internal combustion engine, it is necessary to use a separate fuel other than the waste as the fuel for the gas engine 6. Absent. Therefore, the manufacturing cost and the operating cost of the waste power generation plant 1 can be reduced.

[Second Embodiment]
Hereinafter, the waste power generation plant (waste treatment plant) 1A according to the second embodiment of the present invention will be described with reference to the drawings.
This embodiment is a modification of the first embodiment, and is the same as the first embodiment except for a part particularly described below.

In the waste power generation plant 1A of the present embodiment, the combustion exhaust gas pipe 30 for a gas engine that distributes the combustion exhaust gas discharged from the gas engine 6 and the exhaust gas that guides the combustion exhaust gas discharged from the gas engine 6 to the steam reheater 40. It differs from the waste power generation plant 1 of the first embodiment in that the introduction pipe 31 is provided with a valve for adjusting the flow rate of the circulated combustion exhaust gas.

As shown in FIG. 4, the combustion exhaust gas pipe 30 for a gas engine is provided with an emission control valve 30a for adjusting the flow rate of the combustion exhaust gas discharged to the outside of the waste power generation plant 1. Further, the exhaust gas introduction pipe 31 is provided with an introduction control valve 31a for adjusting the flow rate of the combustion exhaust gas to be introduced into the incinerator 3. The discharge control valve 30a and the introduction control valve 31a have a function of adjusting the valve opening degree in response to a control command from the control device 51.

In the present embodiment, the control device 51 associates the opening degree of the discharge adjusting valve 30a with the output of the gas engine 6 and stores them as a table in advance so that the opening degree corresponds to the output of the gas engine 6. The opening degree of the discharge control valve 30a may be determined with reference to the table. Further, the control device 51 may make the opening degree of the discharge adjusting valve 30a always constant regardless of the output of the gas engine 6. Further, the control device 50 may adjust the opening degree of the discharge adjusting valve 30a so as to be inversely proportional to the opening degree of the introduction adjusting valve 31a.
Further, as another aspect, the discharge control valve 30a may not be provided in the combustion exhaust gas pipe 30 for a gas engine.

Next, the operation of the control device 51 of the present embodiment to control the output of the steam turbine 4 so as to be the target output will be described with reference to the control block diagram of FIG.

As shown in FIG. 5, the control device 51 of the present embodiment includes a lower limit limiter 51A, a correction value calculation unit 51B, and a controller 51C as functional blocks.
In FIG. 5, SSV shows the target value of the steam flow rate supplied from the steam reheater 40 to the low pressure turbine 4B, and SPV shows the measured value of the steam flow rate supplied from the steam reheater 40 to the low pressure turbine 4B. Further, VSV indicates a set value of the opening degree of the introduction adjusting valve 31a, and VPV indicates an actually measured value of the opening degree of the introduction adjusting valve 31a.

As shown in FIG. 5, the control device 51 inputs to the lower limit limiter 51A a value obtained by subtracting the measured value SPV of the steam flow rate supplied to the low pressure turbine 4B from the target value SSV of the steam flow rate supplied to the low pressure turbine 4B. To do. The measured value SPV of the steam flow rate is measured by a flow meter (not shown) provided in the steam reheater 40. The value input to the lower limit limiter 51A becomes a positive value when the measured value SPV is lower than the target value SSV, and the value input to the lower limit limiter 51A is a negative value when the measured value SPV is higher than the target value SSV. It becomes.
As the target value SSV, the target value of the steam flow rate generated in the incinerator 3 itself may be set, or the lower limit value obtained by subtracting a predetermined value from the target value of the steam flow rate generated in the incinerator 3 is set. May be good.

The lower limit limiter 51A outputs the value to the correction value calculation unit 51B when the input value is a positive value, and calculates the correction value of "0" when the input value is a negative value. Output to unit 51B. That is, when the measured value SPV of the lower limit limiter 51A is lower than the target value SSV and it is necessary to heat the steam supplied from the steam reheater 40 to the low-pressure turbine 4B, a positive value is sent to the correction value calculation unit 51B. Output.
When the combustion exhaust gas discharged from the gas engine 6 is constantly flowing to the steam reheater 40, it is necessary to reduce the steam supplied from the steam reheater 40 to the low pressure turbine 4B without using the lower limit limiter 51A. If there is, a negative value may be output to the correction value calculation unit 51B.

The correction value calculation unit 51B calculates the opening degree correction value VCV for correcting the opening degree of the introduction adjusting valve 31a based on the value input from the lower limit limiter 51A. The opening degree correction value VCV is added to the set value VSV of the opening degree of the introduction adjusting valve 31a. A value obtained by subtracting the measured value VPV of the opening degree of the introduction adjusting valve 31a from the value obtained by adding the opening degree correction value VCV and the set value VSV is input to the controller 51C.

The reason why the opening correction value VCV is added to the set value VSV is that when the measured value SPV is lower than the target value SSV, the opening of the introduction adjusting valve 31a is increased to heat the steam. Further, the reason why the measured value VPV of the opening degree of the introduction adjusting valve 31a is subtracted is to give feedback so that the opening degree of the introduction adjusting valve 31a is the value obtained by correcting the set value VSV with the opening degree correction value VCV. Is. The measured value VPV of the opening degree of the introduction adjusting valve 31a is obtained, for example, by measuring the flow rate of the combustion exhaust gas flowing through the introduction adjusting valve 31a with a flow meter (not shown) and converting the value into the opening degree.

The controller 51C generates a control command value for controlling the opening degree of the introduction adjusting valve 31a according to the input value, and outputs the control command value to the introduction adjusting valve 31a which is the control target. The introduction adjusting valve 31a adjusts the opening degree of the introduction adjusting valve 31a based on the control command value input from the controller 51C.

As described above, the control device 51 of the present embodiment is introduced and adjusted so as to compensate for the shortage of the steam flow rate supplied to the low-pressure turbine 4B when the measured SPV is lower than the target value SSV of the steam flow rate. Increase the opening degree of the valve 31a. When the opening degree of the introduction adjusting valve 31a increases, the flow rate of the combustion exhaust gas guided from the introduction adjusting valve 31a to the steam reheater 40 via the exhaust gas introduction pipe 31 increases. Then, as the flow rate of the combustion exhaust gas increases, the temperature of the steam heated by the steam reheater 40 increases, and the output of the steam turbine 4 and the power generation amount of the first generator 7 increase. As described above, the control device 51 of the present embodiment determines the flow rate of the exhaust gas (the amount of heat given to the steam) led from the exhaust gas introduction pipe 31 to the steam reheater 40 so that the output of the steam turbine 4 becomes the target output. Control.

As described above, the waste power generation plant 1A of the present embodiment includes an introduction control valve 31a arranged in the exhaust gas introduction pipe 31 and adjusting the flow rate of the combustion exhaust gas guided to the steam reheater 40. Further, the control device 51 controls the opening degree of the introduction adjusting valve 31a so that the flow rate of the combustion exhaust gas led from the exhaust gas introduction pipe 31 to the steam reheater 40 is adjusted.
The control device 51 adjusts the flow rate of the exhaust gas guided from the exhaust gas introduction pipe 31 to the steam reheater 40 so that the output of the steam turbine 4 becomes the target output, and is generated in the incinerator 3 due to a change in the properties of the waste or the like. Even when the amount of heat generated fluctuates, the output of the steam turbine 4 can be maintained constant.

[Third Embodiment]
Hereinafter, the waste power generation plant (waste treatment plant) according to the third embodiment of the present invention will be described with reference to the drawings.
This embodiment is a modification of the first embodiment and the second embodiment, and is the same as the first embodiment and the second embodiment except for a portion particularly described below.

In the waste power generation plant 1 of the first embodiment, when the measured value SPV is lower than the target value SSV of the steam flow rate, the gas engine 6 compensates for the shortage of the steam flow rate supplied to the low pressure turbine 4B. It increased the output. Further, the waste power generation plant 1A of the second embodiment is introduced and adjusted so as to make up for the shortage of the steam flow rate supplied to the low pressure turbine 4B when the measured SPV is lower than the target value SSV of the steam flow rate. The opening degree of the valve 31a was increased.
On the other hand, in the waste power generation plant of the present embodiment, when the measured value SPV is lower than the target value SSV of the steam flow rate, the gas engine 6 so as to make up for the shortage of the steam flow rate supplied to the low pressure turbine 4B. Both the output of the above and the opening degree of the introduction adjusting valve 31a are increased.

The configuration of the waste power generation plant of the present embodiment is the same as the configuration of the waste power generation plant 1A of the second embodiment except for the control device 52. The control device 52 of the third embodiment is different from the control device 51 of the second embodiment in the content of the operation of controlling the output of the steam turbine 4 so as to be the target output.

As shown in FIG. 4, the combustion exhaust gas pipe 30 for a gas engine is provided with an emission control valve 30a for adjusting the flow rate of the combustion exhaust gas discharged to the outside of the waste power generation plant 1. Further, the exhaust gas introduction pipe 31 is provided with an introduction control valve 31a for adjusting the flow rate of the combustion exhaust gas to be introduced into the incinerator 3. The discharge control valve 30a and the introduction control valve 31a have a function of adjusting the valve opening degree in response to a control command from the control device 52.

Next, the operation of the control device 52 of the present embodiment to control the output of the steam turbine 4 so as to be the target output will be described with reference to the control block diagram of FIG.
As shown in FIG. 6, the control device 52 of the present embodiment includes a lower limit limiter 52A, a correction value calculation unit 50B, a controller 50C, a correction value calculation unit 51B, and a controller 51C as functional blocks. Here, the lower limit limiter 52A is the same as the lower limit limiter 50A of the first embodiment and the lower limit limiter 51A of the second embodiment. Further, the correction value calculation unit 50B and the controller 50C are the same as the correction value calculation unit 50B and the controller 50C of the first embodiment. Further, the correction value calculation unit 51B and the controller 51C are the same as the correction value calculation unit 51B and the controller 51C of the second embodiment.

As described in the first embodiment, the controller 50C generates a control command value for controlling the output of the gas engine 6 according to the input value, and outputs the control command value to the gas engine 6 to be controlled. Here, the control command value is, for example, a command value for adjusting the flow rate of the methane-containing biogas burned by the gas engine 6 and the flow rate of the air used for the combustion. The gas engine 6 controls the output of the gas engine 6 by adjusting various valves (not shown) of the gas engine 6 based on the control command value input from the controller 50C.

Further, as described in the second embodiment, the controller 51C generates a control command value for controlling the opening degree of the introduction adjusting valve 31a according to the input value, and the introduction adjusting valve 31a to be controlled. Output to. The introduction adjusting valve 31a adjusts the opening degree of the introduction adjusting valve 31a based on the control command value input from the controller 51C.

As described above, the control device 52 of the present embodiment is a gas engine so as to make up for the shortage of the steam flow rate supplied to the low pressure turbine 4B when the measured value SPV is lower than the target value SSV of the steam flow rate. Both the output of 6 and the opening degree of the introduction control valve 31a are increased. Specifically, the controller 50C increases the output of the gas engine 6 based on the output correction value ECV calculated by the correction value calculation unit 50B. Further, the controller 51C increases the opening degree of the introduction adjusting valve 31a based on the opening degree correction value VCV calculated by the correction value calculation unit 51B.

[Other Embodiments]
In the above description, the gas engine 6 uses the methane-containing biogas produced in the methane fermentation tank 5 as fuel, but other embodiments may be used. For example, another hydrocarbon-based gas containing methane, butane, propane or the like as a main component may be used as the fuel.

Further, in the above description, the steam turbine 4 connects the high pressure turbine 4A and the low pressure turbine 4B via the rotating shaft 4C, but other embodiments may be used. For example, instead of connecting to the same rotating shaft as the high-pressure turbine 4A and the low-pressure turbine 4B, they may be connected to independent and separate rotating shafts. In this case, the driving force of the separate rotating shafts may be transmitted to the same first generator 7. Further, the driving force of the separate rotating shafts may be transmitted to the independent and separate generators.

1,1A Waste power generation plant (waste treatment plant)
3 Incinerator 3A Input hopper 3B Stoker 3C Primary air supply 3D Incinerator body 3E Boiler 3F Secondary air supply 3G Starter burner 3H Temperature sensor 3I Feeder 4 Steam turbine 4A High pressure turbine 4B Low pressure turbine 4C Rotating shaft 5 methane fermenter 6 Gas engine (internal combustion engine)
7 First generator (turbine generator)
8 Second generator (internal combustion engine generator)
12 Waste supply path 13 Combustion air introduction pipe 14 Garbage pit 15 Waste supply path 16 Exhaust gas exhaust heat recovery device 21 Steam supply pipe 22 Water supply supply pipe 24 Water recovery device 26 Water supply heater 28 Biogas supply pipe 29 Sewage discharge pipe 30 Combustion exhaust gas pipe for gas engine 30a Exhaust gas control valve 31 Exhaust gas introduction pipe (introduction flow path)
31a Introduction control valve 40 Steam reheater (heater)
50, 51, 52 Control device (control unit)
D Waste

Claims (7)

It ’s a waste treatment plant,
An incinerator that burns waste to produce steam,
A high-pressure turbine to which the steam generated by the incinerator is supplied , and
A low-pressure turbine to which the steam discharged from the high-pressure turbine is supplied, and
A steam reheater that heats the steam discharged from the high-pressure turbine and supplies it to the low-pressure turbine .
An internal combustion engine that burns fuel to generate driving force,
An introduction flow path that guides the exhaust gas discharged from the internal combustion engine to the steam reheater ,
When the measured flow rate of the steam supplied from the steam reheater to the low pressure turbine is lower than the flow target value of the steam, the shortage of the flow rate of the steam supplied to the low pressure turbine is compensated. A waste treatment plant including a control unit that controls the amount of heat of the exhaust gas guided from the introduction flow path to the steam reheater . The waste treatment plant according to claim 1, wherein the control unit controls the output of the internal combustion engine so that the amount of heat of the exhaust gas guided from the introduction flow path to the steam reheater is adjusted. It is provided with an introduction control valve arranged in the introduction flow path and adjusting the flow rate of the exhaust gas guided to the steam reheater .
The waste treatment plant according to claim 1, wherein the control unit controls the opening degree of the introduction adjustment valve so that the flow rate of the exhaust gas guided from the introduction flow path to the steam reheater is adjusted. The waste treatment plant according to any one of claims 1 to 3 , further comprising the high-pressure turbine and a turbine generator that generates electricity by a driving force transmitted from the low-pressure turbine . The waste treatment plant according to any one of claims 1 to 4 , further comprising an internal combustion engine generator that generates electricity by the driving force transmitted from the internal combustion engine. The waste treatment plant according to any one of claims 1 to 5 , wherein the internal combustion engine is a gas engine driven by methane-containing biogas generated from the waste. And incinerator waste is burned to generate steam, and low pressure turbine and the high-pressure turbine, said steam discharged from said high pressure turbine is supplied to the steam the incinerator has generated is supplied, the high-pressure turbine A steam reheater that heats the steam discharged from the turbine and supplies it to the low-pressure turbine, an internal combustion engine that burns fuel to generate a driving force, and the steam reheater that exhausts exhaust gas discharged from the internal combustion engine . It is an operation method of a waste treatment plant equipped with an introduction flow path leading to
A measurement process for measuring the measured flow rate of the steam supplied from the steam reheater to the low-pressure turbine, and
The steam reheater from the introduction flow path so as to compensate for the insufficient flow rate of the steam supplied to the low-pressure turbine when the measured flow rate value measured by the measurement step is lower than the flow rate target value of the steam. A method of operating a waste treatment plant, comprising a control step of controlling the amount of heat of the exhaust gas guided to.

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