JPH08312902A - Starting method and device for steam prime plant having a plurality of boilers - Google Patents

Abstract

PURPOSE: To prevent the generation of white smoke by a method wherein the outlet steam temperature of an already operating boiler is reduced to a predetermined temperature upon beginning the parallel operation of a newly started boiler to warm a communicating steam pipe up by the steam of the newly strated boiler, in a steam prime plant consisting of a plurality of boilers provided in parallel. CONSTITUTION: Upon starting a waste heat boiler 1' during the stationary condition operation of another waste heat boiler 1, the pressure of the waste heat boiler 1' is increased at first and, on the other hand, the temperature reducer 4 of the already operating waste heat boiler 1 is provided with a command to lower a control temperature so that an outlet steam temperature is reduced to an allowable temperature at the inlet port of a turbine. After the increase of the pressure of waste heat boiler 1' is finished, a main steam stop valve 17' is opened slightly when the internal pressure of the waste heat boiler 1' has become equal to that of a main steam pipeline 6' to conduct generated steam into the main steam pipeline 6'. According to this method, the pipeline 6' is warmed up and when a steam temperature in the pipeline 6' has become the same level as the operating temperature of an operating steam receiver 11, steam is supplied from the waste heat boiler 1 in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for starting a steam power plant having a plurality of boilers, and more particularly, a plurality of steam generating equipments represented by a municipal solid waste incineration plant for power generation ( It is applied to a plant in which at least one series of turbine power generation equipment is installed, and one or more boilers are newly started and newly started. It is suitable to reduce unnecessary heat loss by shortening the combined time when steam from the boiler is mixed into the turbine, and also to reduce excessive facility load due to temperature difference due to the above. The present invention relates to a control method and apparatus for a steam power plant having a plurality of boilers.

[0002]

2. Description of the Related Art As a typical example of a plant having a plurality of steam generating facilities for one series of steam turbine generators, a power generation process of a general waste incineration plant for power generation consisting of two incinerators will be described with reference to FIG. To do. The steam generating facility, that is, the waste heat boiler 1 utilizes the sensible heat (fuel input heat in the combustion boiler) in the exhaust gas of the municipal waste incinerator generated from the incinerator 2 to generate steam (usually superheated steam).
The generated steam passes through the main steam pipe 6 and usually a steam receiver 1 for the purpose of effectively distributing the steam to other equipment.
1 is supplied. The steam receiver 11 also serves to effectively mix steam supplied from different sources when supplying steam generated by a plurality of boilers to the steam turbine 13 of one series. Steam receiver 11
The steam from is continuously supplied to the steam turbine 13 through the turbine inlet main steam pipe 12, is supplied to the power generation, and then is condensed in the condenser 14. After that, the water is supplied to the waste heat boiler 1 again as boiler water supply with some water supply for makeup.

On the other hand, when the waste heat boiler 1 is operating at a rated load, the waste heat boiler 1'is started by the demand for increasing the amount of waste incinerated, the increase in power generation demind, and other demands other than the above. When the generated steam of the above is introduced into the steam turbine 13 in addition to the boiler startup time due to the normal pressurization process, the boiler outlet main steam pipe 6, the receiver 11, the turbine inlet main that constitute the steam line in operation are To absorb the difference between the temperature of the steam pipe 12 and the steam temperature from the waste heat boiler newly entering, so that excessive thermal stress is not applied to the steam lines 6, 11, 12 and the steam turbine 13 that have been operated, Further, in order to prevent the drain from being generated in the steam due to the temperature difference and carrying the drain to the steam turbine 13, a so-called warm pipe work is required.

However, the steam generated from the newly started waste heat boiler 1'is usually used for this warm pipe. That is, after the completion of pressurization, the steam from the waste heat boiler 1'that has entered the load operation is immediately operated in the steam line (steam receiver 11).
Rather than being combined with the main steam line 6 ', the main steam line 6'at the outlet of the boiler 1'is heated, and the atmospheric release line 16' is kept until the temperature difference at the point of parallel entry to the main steam line in operation is within the allowable value.
Is discharged to the outside of the system by waste water or treated by a blow line. Therefore, the waste heat boiler 1'during hot pipe operation
Vapor generated from the steam is wasted and wasted, and not only heat energy is lost, but also treatment for white smoke when the steam is released to the atmosphere is required.

Particularly in recent plants for high-efficiency power generation thinking, although the time required for the warm-up pipe work tends to basically become longer due to the increase in the main steam temperature, an appropriate operation method for shortening the main work time is required. As for the equipment, it has not been considered yet.

[0006]

The above-mentioned prior art is a method of shortening the warm-up time of pipes and the like which is required when a new boiler (or a plurality of boilers) is being operated while another one is being started up. Therefore, there is a problem that steam released to the atmosphere (or steam discarded as drain) during the warm pipe work is wastefully discarded, and heat energy is lost.

In addition, especially in a refuse incineration plant, in order to reduce the environmental burden on local residents and the like, thorough measures are taken against white smoke generated from the plant even with steam. Therefore, even for this purpose, the time to discharge the steam by the warm pipe should be shortened as much as possible. An object of the present invention is to remove the heat loss due to steam discharge in the conventional warm pipe work described above and to reduce the environmental load due to white smoke generated. A method and an apparatus for starting a steam power plant having a plurality of boilers. To provide.

[0008]

In order to achieve the above object, the invention claimed in the present application is as follows. (1) In a method for starting a steam engine plant that supplies steam from a plurality of boilers to at least one steam turbine through a main steam supply system, steam of a predetermined temperature is shared by one or more boilers. During generation of power to be supplied to the steam turbine via the steam supply system, one or more boilers are newly started to supply steam from the newly started boiler to the steam turbine via the main steam supply system. When entering, the outlet steam temperature of the boiler that is already in operation is reduced from the predetermined temperature to continue the operation of the steam turbine, and the steam generated by starting a new start boiler supplies the common main steam to the boiler. Perform a warming of the connecting steam pipe with the system, and when the boiler outlet steam temperature reaches the temperature at which it can be combined with the already operating boiler outlet steam temperature, insert a new startup boiler together. Starting the steam motive plant with a plurality of boilers to symptoms.

(2) A plurality of boilers each having a superheater and a steam temperature control device for controlling the steam temperature at the outlet of the superheater, a steam receiver for receiving steam from the boilers, and steam in the receivers having a main steam pipe. And one or more steam turbines supplied via the steam generator, and when supplying steam at a predetermined temperature to the steam turbine from an already-operated boiler, newly starts and joins the boiler, and starts a steam power plant having a plurality of boilers. In the apparatus, the steam turbine inlet steam temperature detecting means during operation, and the heater outlet steam temperature of the operating boiler is set to the predetermined temperature so that the wetness of the turbine outlet steam becomes an allowable value based on the value detected by the means. The means for controlling the following reduced temperature, the means for starting a new boiler to be inserted together and raising the outlet steam temperature to the reduced temperature, and the new boiler outlet steam temperature for the reduced temperature A means for detecting that it has reached a near distance and is ready for co-merging, a means for coordinating the outlet steam of the new boiler to the steam receiver based on the detection result, and a means for co-merging with the already-operated boiler. A starting device for a steam engine plant having a plurality of boilers, comprising: a means for raising an outlet steam temperature of the combined boiler to the predetermined temperature.

[0010]

[Operation] The allowable steam temperature at the turbine inlet is not generally determined by the turbine specifications, structure, materials, etc., but generally it is possible to keep the wetness within the allowable range as the steam condition at the turbine outlet. It becomes the inlet steam temperature.

[0011]

[Formula 1] t min = f (exhaust gas wetness) t min: turbine inlet allowable steam temperature As an example, the current inlet steam condition is as follows.
If there is a steam turbine power generation facility that can achieve 000 kW, the outlet steam pressure will be an exhaust condensing turbine of 0.5 ata. Since the exhaust wetness of this equipment is about 2% to 3%, if the wetness is acceptable up to 10%, the inlet steam temperature can be reduced to about 290 ° C.

Inlet steam condition: 40 ata × 400 ° C. Swallowed steam flow rate: 19 t / h On the other hand, in the steam generating facility (waste heat boiler 1), the superheater is used to control the temperature of the outlet steam of the superheater to a constant temperature. The desuperheater 4 is installed. During normal operation, this desuperheater controls the temperature by detecting the steam temperature at the outlet of the superheater with the temperature detector 5. Since the temperature is controlled by the temperature setting converter, a function to change the contact is added.

Now, in a power plant comprising two series of boilers equipped with a superheater desuperheater 4 having this function,
A method of newly starting another boiler in series while the boiler is operating will be described below with reference to FIG. While the waste heat boiler 1 is operating at the rated load, when the waste heat boiler 1'is started up from the cold can, the burner installed in the furnace first starts the boosting work. As shown in FIG. 1, after the waste heat boiler 1 ′ has started the boosting work, the waste heat boiler 1 already in operation
A signal for reducing the steam temperature is transmitted from the temperature setting converter. Based on this signal, the steam temperature of the waste heat boiler 1 is reduced by the superheater desuperheater 4. In this work, a sudden change in the steam temperature causes an excessive thermal stress to the steam turbine 13, so contact adjustment is performed so as to perform a reduction work while ensuring a certain transition time (usually about 5 ° C./min). It is a sequence. Since it is important to strictly control the steam temperature at the turbine inlet from the viewpoint of turbine protection, a steam temperature detection contact 18 is provided at the turbine inlet, and the temperature from this detector 18 is constantly fed back during the temperature reduction work. Control. By this process, the waste heat boiler 1 in the already operated state reduces the main steam temperature from the rated temperature to the lower limit value of the steam temperature at the turbine inlet by the time the pressure of the newly started waste heat boiler 1'is completed. In the above-described example, the main steam temperature is reduced to 290 ° C. before the pressurization of the waste heat boiler 1 ′, which is newly activated by the waste heat boiler 1 operating at the rated temperature of 400 ° C., is completed.

After the pressure of the newly started waste heat boiler 1'is completed, as soon as the internal pressure of the waste heat boiler 1'and the pressure of the main steam pipe 6'become the same, the main steam stop valve 17 'is opened slightly and the temperature is continuously raised. Become a process. At this point in time, as described above, the operating temperature of the boiler 1 already in operation has already reached the lower limit temperature of the turbine inlet (290 ° C. in the above example).
Since the warming process that originally needed to raise the temperature to the rated temperature (400 ° C. in the above example) can be done by raising it to the turbine inlet lower limit temperature (290 ° C. in the above example).
It is possible to shorten the time required for the generated steam to be released into the atmosphere, which is required for the warm pipe.

In order to solve the above-mentioned problems of the prior art, a starting method is proposed in which the heat release time is shortened as much as possible to eliminate heat loss and the white smoke generation time due to the steam release is reduced. Normal steam generation facility (Fig. 1
According to this, a superheater desuperheater 4 is installed in the waste heat boiler 1, 1 ') to control the generated steam temperature to a set planned temperature. The desuperheater 4 operates to detect the steam temperature at the outlet of the superheater during normal operation and control the main temperature to a constant planned temperature, but in addition to this function, central operation (central operation room)
The temperature contact is changed by a command from the temperature setting converter, etc. so that the temperature can be controlled and changed to any temperature.

On the other hand, if the steam temperature at the turbine 13 inlet is within a certain range of wetness of the steam at the turbine outlet,
It can be lowered unless a sudden temperature change is made. Therefore, it is possible to shorten the time required for warming up the newly started steam generation facility by lowering the steam temperature during the operation to the turbine inlet allowable temperature by the function of the superheater desuperheater 4 described above. Becomes

[0017]

EXAMPLES Examples of the present invention will be described in detail below. FIG. 1 shows a power generation system for a municipal waste incinerator in which one series of turbine generators is installed for two series of waste heat boilers provided with a warm pipe system consisting of a superheater desuperheater 4 and an atmospheric discharge line 16 according to the present invention The system of equipment is shown.

The exhaust gas generated from the municipal waste burned in the incinerator 2 is introduced into the waste heat boiler 1, and steam is generated in the waste heat boiler 1 by the sensible heat of the exhaust gas. When the generated steam is normally used for the purpose of power generation, it is superheated in the superheater 3 in order to improve the power generation output. A desuperheater 4 is installed in the superheater so that the temperature of the superheated steam becomes a constant design value. During normal operation, the superheater outlet steam temperature is detected by the same temperature, and the controller 5 detects the steam temperature to keep the steam temperature constant. It is a mechanism to control. on the other hand,
The desuperheater 4 includes a steam temperature detection at the outlet of the superheater and a controller 5
Separately, a mechanism for changing the control temperature by a signal from the temperature setting converter is provided, and when the waste heat boiler 1'is started from the cold can state, the steam temperature controlled by the signal of the temperature setting converter is designed. The mechanism will allow the temperature to be lowered from the rated temperature to the lower limit temperature allowable at the steam turbine inlet. Further, a detector 18 for detecting the steam temperature at the turbine inlet is provided at the inlet of the steam turbine 13 so that the steam temperature at the turbine inlet is always fed back during the operation for reducing the above-mentioned superheated steam temperature. Shall be set so that it does not fall below the turbine inlet temperature allowable value.

The main steam pipe 6 from the waste heat boiler 1 is introduced into the steam receiver 11, and the steam generated in the main receiver 11 is mixed and supplied to other equipment including the steam turbine 13. Has become. Atmosphere discharge lines 16 and 16 'are provided near the main steam pipes 6 and 6'intake ports of the steam receiver 11 for the purpose of warming the main steam pipes. During the 1-series steady operation, the boiler 1, the boiler outlet main steam pipe 6, the steam receiver 11, the turbine inlet main steam pipe 12 and the steam turbine 13 are at the facility temperature based on the rated steam temperature. Therefore, the waste heat boiler 1 is newly added. ′
When starting, the steam cannot be mixed in until the generated steam reaches the same level as the rated temperature. Therefore, when the steam system of another line is newly started, the air release line 16 'is opened and the steam receiver 1'is discharged from the waste heat boiler 1'.
A system to warm up the steam lines up to 1 is prepared.

In this case, if the waste heat boiler 1 already in operation is taken as a countermeasure, the atmosphere discharge line 16 'is used.
Had to be kept open until the newly started piping equipment 6 ′ reached the rated temperature. However, if a measure is taken in advance to lower the temperature of the superheated steam generated from the boiler 1 which is already in operation to the turbine allowable value as described above, it is possible to significantly reduce the atmospheric release time.

In FIG. 1, when the waste heat boiler 1'is started while the waste heat boiler 1 is operating in a steady state, first, the waste heat boiler 1'starts up the pressure. While increasing the pressure of the waste heat boiler 1 ', a command is issued to the desuperheater 4 of the waste heat boiler 1 which is already in operation to lower the control temperature so as to lower the outlet steam temperature to an allowable temperature at the turbine inlet. After the pressure rise of the waste heat boiler 1'is completed, the main steam stop valve 17 'is opened slightly as soon as the internal pressures of the waste heat boiler 1'and the main steam pipe 6'become the same, and the generated steam flows through the boiler outlet main steam pipe 6'. Flowing. The main steam pipe 6 '
In the state in which the drain is sufficiently cooled, part of the generated steam becomes drain, so the drain valve 7'is open until the main drain is no longer generated, and the drain that is generated is discharged from here to the outside of the piping. . The drain valve 7'is closed as soon as the pipe 6'is warmed up and the drainage is stopped, and the atmosphere discharge valve 9'is opened instead. Generated steam is released into the atmosphere line 1
Boiler outlet main steam pipe 6'while being discharged from 6 '
Is heated. As soon as the steam temperature in the main steam pipe 6'becomes the same level as the operating temperature of the steam receiver 11 in operation, the atmosphere release valve 9'will be closed, and instead the steam receiver inlet stop valve 10 'will be opened and the waste heat boiler will be opened. Steam from 1'is admitted.

However, at this point in time, as the preceding operation, the outlet steam temperature of the waste heat boiler 1 which has been already operated is lowered as much as possible as described above, and therefore the steam is released after the atmosphere release valve 9'is opened. The time until it is inserted into the receiver 11 can be shortened compared to the case where the waste heat boiler 1 that is already in operation is operated without any countermeasure. FIG. 3 shows a conventional time schedule at startup, and FIG. 4 shows a time schedule when the present invention is adopted. When started by the conventional start method A
Steam corresponding to the area surrounded by BCD is released,
When the present invention is adopted, it is only necessary to discharge the vapor corresponding to the area surrounded by A'B'C'D '.

[0023]

According to the present invention, the time required to release the atmosphere required for the temperature rising process of the steam generator 1'which is newly started up is shortened, so that the heat energy wasted as an atmospheric release is reduced. Is possible. According to the present invention, not only is waste heat loss due to atmospheric air emission of vapor reduced, but also white smoke emission time due to vapor emission (white smoke prevention measures such as vapor cooling or forced diffusion by a fan or the like). It is possible to reduce the countermeasure time).

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of an municipal solid waste power generation plant according to the present invention.

FIG. 2 is a system diagram of a conventional municipal waste power generation plant.

FIG. 3 is a diagram showing a time schedule of activation according to a conventional technique.

FIG. 4 is a diagram showing a time schedule of activation according to the present invention.

[Explanation of symbols]

1, 1 '... Waste heat boiler 2, 2' ... Incinerator 3, 3 '...
Superheater 4, 4 '... Superheater desuperheater 5, 5' ... Superheater outlet steam temperature detector 6, 6 '... Boiler outlet main steam pipe,
7, 7 '... Drain valve, 8 ... Atmospheric emission silencer,
9, 9 '... Atmosphere release valve, 10 10' ... Steam receiver stop valve, 11 ... Steam receiver, 12 ... Turbine inlet main steam piping, 13 ... Steam turbine, 14 ... Condenser, 15 ... Condensate tank, 16 , 16 '... Atmospheric release line, 17, 17'
… Main steam stop valve, 18… Turbine inlet steam temperature detector.

Claims (2)

[Claims] 1. A method of starting a steam engine plant, wherein steam from a plurality of boilers is supplied to at least one steam turbine through a main steam supply system, and steam having a predetermined temperature is shared by the one or more boilers. During the generation of power to be supplied to the steam turbine via the main steam supply system, one or more boilers are newly started, and steam from the newly started boiler is supplied to the steam turbine via the main steam supply system. When the supply is mixed, the outlet steam temperature of the boiler in operation is reduced from the predetermined temperature to continue the operation of the steam turbine, and the steam generated by starting the new start boiler causes the boiler and the common main Warm up the connecting steam pipe with the steam supply system, and when the boiler outlet steam temperature reaches the temperature at which it can be combined with the boiler outlet steam temperature in operation, insert a new start boiler. A method for starting a steam engine plant having a plurality of boilers, characterized in that. 2. A plurality of boilers each having a superheater and a steam temperature control device for controlling the steam temperature at the outlet of the superheater, a steam receiver for receiving steam from the boilers, and steam in the receivers through a main steam pipe. A starter for a steam engine having a plurality of boilers, which is equipped with one or more steam turbines supplied via In the steam turbine inlet steam temperature detecting means in operation, the heater outlet steam temperature of the operating boiler is equal to or lower than the predetermined temperature so that the wetness of the turbine outlet steam becomes an allowable value based on the value detected by the means. Means for controlling to the reduced temperature of the new boiler, means for activating a new boiler to be inserted together and raising the outlet steam temperature to the reduced temperature, and the new boiler outlet steam temperature near the reduced temperature. Means to detect that it has reached the point where it can be merged, and means to merge the outlet steam of the new boiler to the steam receiver based on the detection result; A starting device for a steam engine plant having a plurality of boilers, comprising: a means for raising an outlet steam temperature of the boiler to the predetermined temperature.