JP2005201102A - Combined power generation plant and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combined power generation plant which prevents rapid change of inlet stream temperature of a steam turbine and can continue an operation of a steam turbine type power-generating device, and its control method. <P>SOLUTION: The combined power generation plant comprises a plurality of gas turbine type power-generating devices 300, a waste heat boiler 101, superheaters 104a and 104b disposed on the exhaust side of gas turbines 301a and 301b, respectively, a steam turbine type power-generating device 200, blocking means 106a and 106b for blocking steam flowing into the superheaters 104a and 104b, respectively, trip detecting means 113a and 113b for detecting the trip of each gas turbine type power-generating device 300, and a controller 400 for controlling the operation of the combined power generation plant. The controller 400 is constituted so that, when information related to the trip of each gas turbine type power-generating device 300 is acquired, the blocking means corresponding to the superheater on the gas turbine type power-generating device side having tripped is blocked based on the information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a combined power plant and a control method therefor, in which steam generated from a steam generator such as a waste heat boiler is heated with exhaust gas from a gas turbine and the steam turbine is driven using the superheated steam.

  In general, combined power plants that are applied to waste incinerators, etc. use gas turbine power generators, waste heat boilers that recover waste heat from waste incinerators and generate steam, and waste heat from gas turbines. And a superheater that superheats the steam generated in the waste heat boiler, and a steam turbine generator that is driven by the superheated steam that is superheated in the superheater. With this configuration, the power generation amount is increased and the overall thermal efficiency is increased.

  However, in this combined power plant, when the gas turbine power generator trips and the superheat temperature of the steam supplied to the steam turbine (the steam temperature at the inlet of the steam turbine) changes abruptly, thermal stress is applied to the blades of the steam turbine. May occur and affect the life of the blades. Therefore, when the gas turbine power generator trips, the steam turbine power generator also trips.

  In order to cope with this, in the combined power plant disclosed in Patent Document 1, for example, when a trip of the gas turbine power generation device is detected, the steam temperature at the inlet of the steam turbine is increased by increasing the steam temperature at the outlet of the waste heat boiler. Control is performed so as to suppress the change in temperature within an allowable temperature difference range.

However, in this control method, since the outlet steam temperature of the waste heat boiler is increased, the tube wall temperature of the waste heat boiler may reach the high temperature corrosion region. In addition, when the difference between the temperature rise rate when increasing the outlet steam temperature of the waste heat boiler and the rate of decrease in steam turbine outlet steam temperature due to a trip of the gas turbine power generator is large, the steam temperature at the inlet of the steam turbine is abrupt. The temperature difference may exceed the allowable range.
JP-A-7-119415 (FIG. 1)

  The present invention has been made in view of the above-described circumstances, and provides a combined power generation plant capable of preventing a sudden change in the inlet steam temperature of a steam turbine and continuing the operation of the steam turbine power generator and a control method thereof. For the purpose.

  A combined power plant according to the present invention generates steam by using a plurality of gas turbine power generators, a steam generator for generating steam, and exhaust gas discharged from each gas turbine provided on the exhaust side of each gas turbine. A superheater that superheats steam generated in the apparatus, a steam turbine generator that is driven by superheated steam that is superheated in each superheater, shut-off means that shuts off the steam that flows into each superheater, and each gas turbine Provided with a trip detection means for detecting a trip of each gas turbine type power generation device, and a control device for controlling the operation of the combined power plant. The control device comprises a trip detection means. Obtained information on trips to some of the gas turbine generators from the gas turbine generators To, and is configured to block the blocking means corresponding to the trip gas turbine power generation apparatus of the superheater on the basis of this information.

  According to this configuration, it is possible to avoid supply of steam that is not overheated to the steam turbine by shutting off the steam flowing into the superheater on the gas turbine power generation device side that has tripped by the shut-off means. This makes it possible to avoid a rapid change in the inlet temperature of the steam turbine. As a result, the operation of the steam turbine power generator can be continued.

  In addition, since a plurality of gas turbine power generators are provided, when a part of the gas turbine power generator trips, the blocked steam is distributed to the superheater on the side of the gas turbine power generator that is in operation. Then, it can be heated to a predetermined temperature and supplied to the steam turbine. As a result, the steam flow rate at the inlet of the steam turbine can be brought close to the steam flow rate before the gas turbine power generator trips. As a result, a significant decrease in the amount of power generated by the combined power plant can be suppressed.

  Moreover, the combined power plant according to the present invention includes a turbine bypass passage that bypasses the gas turbine power generator and the steam turbine power generator by communicating the outlet side passage of the steam generator and the outlet side passage of the steam turbine; And a first flow rate adjusting means for adjusting the steam flow rate in the turbine bypass passage interposed in the middle of the turbine bypass passage, wherein the control device shuts off the shut-off means and opens the first flow-rate adjusting means. By controlling the degree, it is preferable that part or all of the steam blocked by the blocking means is discharged to the outlet side passage of the steam turbine through the turbine bypass passage.

  According to this configuration, by controlling the opening degree of the first flow rate adjusting means and discharging part or all of the blocked steam to the outlet side passage of the steam turbine through the turbine bypass passage, the gas that is continuously operated It is possible to suppress excessive steam from flowing into the superheater on the turbine power generator side. Thereby, it is possible to suppress a rapid change in the outlet steam temperature of the superheater, that is, the inlet steam temperature of the steam turbine, and the operation of the steam turbine power generator can be continued.

  The combined power plant according to the present invention further includes a flow rate measuring unit that measures a flow rate of the steam flowing into each superheater, and the control device is a turbine based on flow rate information regarding the steam flow rate obtained from the flow rate measuring unit. It is preferable that the flow rate of the steam to be discharged to the outlet side passage of the steam turbine is calculated through the bypass passage, and the opening degree of the first flow rate adjusting means is controlled based on the calculated flow rate.

  According to this configuration, the flow rate of steam to be discharged to the outlet side passage of the steam turbine through the turbine bypass passage can be accurately calculated. More specifically, the flow rate of steam to be discharged to the outlet side passage of the steam turbine through the turbine bypass passage is the sum of the steam flow rates flowing to each superheater immediately before the gas turbine power generator trips, and the operation is continued. It is calculated from the difference with the sum total of the steam flow rate which can be made to flow through each superheater by the side of the gas turbine type power generating device which is. Based on this flow rate, the opening degree of the first flow rate adjusting means is controlled. Thereby, it is suppressed that excessive steam flows into the superheater on the side of the gas turbine power generator that is continuously operated. As a result, it is possible to suppress a rapid change in the inlet steam temperature of the steam turbine, and it is possible to continue the operation of the steam turbine power generator.

  The combined power plant according to the present invention includes a superheater bypass passage that bypasses the superheater by communicating the outlet side passage of the steam generator and the outlet side passage of the superheater, and is interposed in the middle of the superheater bypass passage. And a second flow rate adjusting means for adjusting the steam flow rate in the superheater bypass passage, and a first flow rate adjusting means after a predetermined time has elapsed from when the control device has transferred the steam to the turbine bypass passage. The steam of the turbine bypass passage is transferred to the superheater bypass passage and supplied to the steam turbine by gradually decreasing the opening of the second flow rate and gradually increasing the opening of the second flow rate adjusting means. Is preferred.

  According to this configuration, the steam discharged to the outlet side passage of the steam turbine through the turbine bypass passage is supplied to the steam turbine through the superheater bypass passage. The steam flow before tripping can be restored. Thereby, the thermal energy of the steam discharged to the outlet side passage of the steam turbine through the turbine bypass passage can be recovered as electric energy using the steam turbine. As a result, a significant decrease in the amount of power generated by the combined power plant can be suppressed.

  At this time, steam that is not superheated is mixed with superheated steam that is supplied to the steam turbine from the superheater on the side of the gas turbine power generation device that is operating continuously, so the steam temperature at the inlet of the steam turbine decreases. However, as described above, after a predetermined time has elapsed since the steam was transferred to the turbine bypass passage, that is, after the operating state (pressure, temperature, flow rate, etc.) of the combined power plant has stabilized, the steam that is not overheated is rapidly increased. However, the steam temperature at the inlet of the steam turbine does not change rapidly. As a result, the operation of the steam turbine can be continued.

  The combined power plant according to the present invention further includes pressure measuring means for measuring the pressure of the steam upstream of the first flow rate adjusting means, and the control device transfers the steam in the turbine bypass passage to the superheater bypass passage. The second flow rate adjustment so that the opening of the first flow rate adjusting means is gradually decreased and the pressure becomes a preset target value based on the information on the steam pressure obtained from the pressure measuring means. It is preferably configured to control the opening of the means.

  According to this configuration, the steam discharged to the outlet side passage of the steam turbine through the turbine bypass passage is supplied to the steam turbine through the superheater bypass passage only by reducing the opening of the first flow rate adjusting means. can do. That is, when the opening degree of the first flow rate adjusting means is gradually reduced, that is, when the steam flow rate in the turbine bypass passage is gradually reduced, the steam pressure upstream of the first flow rate adjusting means increases. When this pressure exceeds a preset target value, the opening degree of the second flow rate adjusting means increases so that this pressure matches the target value. Thereby, the steam of the turbine bypass passage can be transferred to the superheater bypass passage.

  In this configuration, the steam flow rate supplied to the steam turbine through the superheater bypass passage can be adjusted by appropriately setting the speed at which the steam flow rate in the turbine bypass passage is reduced. Thereby, it is possible to avoid a rapid change in the inlet steam temperature of the steam turbine.

  A control method for a combined power plant according to the present invention includes a plurality of gas turbine power generators, a steam generator for generating steam, and exhaust gas discharged from each gas turbine provided on the exhaust side of each gas turbine. A superheater that superheats the steam generated in the steam generator, a steam turbine generator that is driven by the superheated steam superheated by each superheater, and a shut-off means that shuts off the steam that flows into each superheater, and A control method applied to a combined power plant including trip detection means for detecting trips of each gas turbine power generator, wherein the trip detection means is part of a plurality of gas turbine power generators. When it is detected that the power generator has tripped, the shut-off means has tripped to the superheater on the gas turbine power generator side. Having a blocking step of blocking the steam inlet.

  According to this control method, it is possible to avoid supply of steam that is not overheated to the steam turbine by shutting off the steam that flows into the superheater on the gas turbine power generation device side that has tripped by the shutoff means. This makes it possible to avoid a rapid change in the steam temperature at the inlet of the steam turbine. As a result, the operation of the steam turbine power generator can be continued.

  Another combined power plant control method according to the present invention includes a plurality of gas turbine power generators, a steam generator for generating steam, and exhausts from each gas turbine provided on the exhaust side of each gas turbine. A superheater that superheats the steam generated in the steam generator by the exhaust gas, a steam turbine power generator driven by the superheated steam superheated by each superheater, and a shut-off means that shuts off the steam flowing into each superheater. And a trip detection means for detecting a trip of each gas turbine power generator, and a turbine bypass passage communicating the outlet side passage of the steam generator and the outlet side passage of the steam turbine. A control method, wherein the trip detection means includes a part of the plurality of gas turbine generators. When detecting the rip, the shut-off process for shutting off the steam flowing into the superheater on the gas turbine power generator side where the shut-off means has tripped, and the steam shut off by the shut-off means are continued in the turbine bypass passage and the operation. And a first transition step of transitioning to the superheater on the gas turbine power generator side.

  According to this control method, a part or all of the shut-off steam is discharged to the outlet side passage of the steam turbine through the turbine bypass passage, so that excessive steam is supplied to the superheater on the side of the gas turbine generator that is continuously operated. Can be prevented from flowing in. Thereby, it is possible to suppress a rapid change in the outlet steam temperature of the superheater, that is, the inlet steam temperature of the steam turbine, and the operation of the steam turbine power generator can be continued.

  Another combined power plant control method according to the present invention includes a plurality of gas turbine power generators, a steam generator for generating steam, and exhausts from each gas turbine provided on the exhaust side of each gas turbine. A superheater that superheats the steam generated in the steam generator by the exhaust gas, a steam turbine generator that is driven by the superheated steam that is superheated by each superheater, and a shut-off means that shuts off the steam that flows into each superheater. A trip detection means for detecting a trip of each gas turbine power generator, a turbine bypass passage communicating the outlet side passage of the steam generator and the outlet side passage of the steam turbine, and an outlet side passage of the steam generator, A control method applied to a combined power plant including a superheater bypass passage communicating with an outlet-side passage of a superheater. When the detecting means detects that some of the gas turbine power generators have tripped, the steam flowing into the superheater on the gas turbine power generator side where the shut-off means has tripped is detected. A shut-off process for shutting off, a first transition process for transferring the steam shut off by the shut-off means to the turbine bypass passage and the superheater on the side of the gas turbine power generator that is in operation, and when steam is transferred to the turbine bypass passage And a second transition step of gradually transitioning the steam transferred to the turbine bypass passage to the superheater bypass passage after a predetermined time has elapsed.

  According to this control method, since the steam that has been transferred to the turbine bypass passage is gradually transferred to the superheater bypass passage, the change in the steam temperature at the inlet of the steam turbine is suppressed within an allowable range. The operation of the power generation device can be continued. Further, the steam transferred to the turbine bypass passage is gradually transferred to the superheater bypass passage, so that the steam flow rate at the inlet of the steam turbine can be returned to the steam flow rate before the trip of the gas turbine power generator. As a result, a significant decrease in the amount of power generated by the combined power plant can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the rapid change of the inlet steam temperature of a steam turbine can be prevented, and the driving | operation of a steam turbine type electric power generating apparatus can be continued.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a flowchart showing a configuration of a combined power plant according to an embodiment of the present invention. Here, a case where the combined power plant is applied to a known waste incinerator will be described as an example.

  As shown in FIG. 1, the combined power plant includes a publicly known waste incinerator 100 that incinerates municipal waste, a steam turbine power generator 200 that uses waste heat of the waste incinerator 100, a gas turbine power generator 300, And a control device 400 for controlling these devices.

  Although the garbage combustion furnace 100 is not illustrated, the waste incinerator outlet gas pipe line communicates with the chimney through the flue. In the middle of the flue, a waste heat boiler 101 is installed that recovers thermal energy in the exhaust gas discharged from the waste incinerator 100 and generates steam.

  The waste heat boiler 101 communicates with the steam turbine power generation device 200 through a steam supply line 102 in order to supply steam generated in the waste heat boiler 101 to the steam turbine power generation device 200. In the steam supply passage 102, a steam reservoir tank 103 for storing steam in order from the waste heat boiler 101 side, and a No. 1 superheater 104a and a No. 2 superheater 104b described later are installed.

  The steam turbine power generator 200 is obtained by connecting a steam turbine 201 and a generator 202 in series. A steam supply line 102 communicates with an air supply port of the steam turbine 201, and a steam condenser 204 communicates with an exhaust port of the steam turbine 201 through a condensate line 203. A first regulating valve 205 is installed on the upstream side of the air supply port of the steam turbine 201 in the steam supply line 102. Further, a steam turbine bypass pipe 206 is provided that bypasses the steam turbine power generator 200 and communicates the upstream side of the first regulating valve 205 of the steam supply pipe 102 with the condensate pipe 203. A bypass valve 207 is installed in the steam turbine bypass pipeline 206. Thereby, when the steam turbine power generation device 200 breaks down, the steam supplied to the steam turbine 201 can be shut off and the shut off steam can be returned to the steam condenser 204.

  The gas turbine type power generator 300 includes a No. 1 gas turbine type power generator 300a and a No. 2 gas turbine type power generator 300b. A No. 1 gas turbine power generator 300a is obtained by connecting a No. 1 gas turbine 301a, a No. 1 compressor 302a, and a No. 1 generator 303a in series. The exhaust port of the No. 1 gas turbine 301a communicates with a chimney (not shown) through the No. 1 exhaust pipe 304a. The No. 1 exhaust pipe 304a is provided with a No. 1 superheater 104a that recovers thermal energy in the exhaust gas discharged from the No. 1 gas turbine 301a and superheats steam supplied from the waste heat boiler 101 to a predetermined temperature. ing. The No. 2 gas turbine power generator 300b has the same configuration.

  It is desirable that the No. 1 gas turbine type device 300a and the No. 2 gas turbine type power generation device 300b are set so as to have substantially the same capacity. As a result, the incidental facilities such as the No. 1 superheater 104a and the No. 2 superheater 104b can have almost the same capacity and shape, which simplifies the entire facility and leads to cost reduction. Of course, the No. 1 gas turbine power generator 300a and the No. 2 gas turbine power generator 300b may have different abilities. In that case, incidental facilities such as No. 1 superheater 104a and No. 2 superheater 104b are set according to the respective capacities of the No. 1 gas turbine power generator 300a and the No. 2 gas turbine power generator 300b. Here, two gas turbine power generators are provided, but any number of gas turbine power generators may be installed as long as there are two or more.

  Further, the superheat capacity of each superheater 104a, 104b is set with a margin (for example, 20%) with respect to the superheat capacity during normal operation in consideration of fluctuations in the operating conditions of these superheaters 104a, 104b. Therefore, it is possible to flow steam to each superheater 104a, 104b up to a steam flow rate corresponding to this margin. This steam flow rate corresponds to the maximum value G4 of the steam flow rate that can be introduced into each superheater 104a, 104b described later. As a result, when one of the two gas turbine power generators 300a and 300b trips and shuts down the corresponding No. 1 superheater shut-off valve 106a or No. 2 superheater shut-off valve 106b corresponding thereto, as will be described later. In addition, a part of the shut-off steam can be flowed to the superheater corresponding to the gas turbine power generator that is continuously operated.

  The steam supply pipe 102 is branched into two branch pipes 105a and 105b on the downstream side of the steam tank 103, and these branch pipes 105a and 105b are connected to the first superheater 104a and the second superheater 104b. Each communicates. A branch valve 105a on the side of the No. 1 superheater 104a of the steam supply pipe 102 is provided with a No. 1 superheater shut-off valve 106a that shuts off the steam flowing into the No. 1 superheater 104a. Similarly, a No. 2 superheater shut-off valve 106b for shutting off the steam flowing into the No. 2 superheater 104b is installed in the branch pipe 105b on the No. 2 superheater 104b side of the steam supply pipe 102. Steam outlet pipes 105c and 105d communicate with the exhaust sides of the No. 1 superheater 104a and the No. 2 superheater 104b, respectively. These steam outlet pipes 105 c and 105 d are merged on the steam turbine 201 side and communicate with the inlet of the first regulating valve 205. These exhaust pipe lines 105 c and 105 d constitute a part of the steam supply pipe line 102.

  The steam supply pipe 102 is provided with a No. 1 superheater 104 a and a No. 2 superheater 104 b and a turbine bypass pipe 107 that bypasses the steam turbine 201. The turbine bypass pipe 107 is branched from a portion of the steam supply pipe 102 between the steam reservoir tank 103 and the branch pipes 105 a and 105 b, and communicates with the condensate pipe 203. Here, the turbine bypass pipe 107 is branched from a portion of the steam supply pipe 102 between the steam reservoir tank 103 and the branch pipes 105a and 105b. However, the present invention is not limited to this. For example, the turbine bypass pipe 107 may be branched from the upstream portion of the No. 1 superheater shut-off valve 106a and the No. 2 superheater shut-off valve 106b of the branch pipes 105a and 105b.

  The turbine bypass pipe 107 is provided with a turbine bypass shut-off valve 108 and a second adjustment valve 109 for adjusting the flow rate of the steam flowing through the turbine bypass pipe 107 in order from the steam reservoir tank 103 side. The turbine bypass cutoff valve 108 and the second adjustment valve 109 constitute a first flow rate adjusting means. Further, the exhaust gas side of the steam turbine bypass pipe 206 described above communicates with a portion of the turbine bypass pipe 107 between the second adjustment valve 109 and the condensate pipe 203. Thereby, the turbine bypass pipeline 107 constitutes a part of the steam turbine bypass pipeline 206. Of course, the steam turbine bypass pipeline 206 may be provided separately from the turbine bypass pipeline 107 and directly communicated with the condensate pipeline 203.

  The steam supply line 102 is provided with a superheater bypass line 110 that bypasses the No. 1 superheater 104a and the No. 2 superheater 104b. The superheater bypass pipe 110 is branched from a portion of the turbine bypass pipe 107 upstream of the turbine bypass shutoff valve 108 and extends from the confluence of the steam outlet pipes 105c and 105d to the inlet of the steam turbine bypass pipe 206. It communicates with the part between. The superheater bypass pipe 110 is provided with a third adjustment valve (second flow rate adjusting means) 111 for adjusting the flow rate of the steam flowing therethrough. Thereby, the turbine bypass conduit 107 constitutes a part of the superheater bypass conduit 110. Of course, the superheater bypass line 110 may be provided separately from the turbine bypass line 107. That is, the superheater bypass line 110 may be branched directly from the steam supply line 102.

  Further, the steam reservoir tank 103 is provided with a pressure measuring device 112 for measuring the steam pressure therein. The No. 1 gas turbine type power generator 300a is provided with a No. 1 gas turbine trip detector 113a for detecting that the No. 1 gas turbine type power generator 300a has tripped. Similarly, the No. 2 gas turbine power generator 300b is provided with a No. 2 gas turbine trip detector 113b for detecting that the No. 2 gas turbine power generator 300b has tripped. The first superheater for measuring the flow rate of the steam flowing into the first superheater 104a is provided in a portion between the first superheater 104a and the first superheater shutoff valve 106a of the branch pipe 105a on the first superheater 104a side. A functional flow meter 114a is provided. Similarly, the flow rate of the steam flowing into the No. 2 superheater 104b is measured at a portion between the No. 2 superheater 104b and the No. 2 superheater shut-off valve 106b of the branch pipe 105b on the No. 2 superheater 104b side. No. superheater flow rate measuring device 114b is provided.

  Although not shown, the control device 400 includes a control calculation unit, a storage unit, and an input / output unit, and performs monitoring and control of the combined power plant according to the present embodiment. The control device 400 is communicably connected to the pressure measuring instrument 112. The control device 400 is communicably connected to the No. 1 gas turbine trip detector 113a and the No. 2 gas turbine trip detector 113b. The control device 400 is connected to the No. 1 superheater flow rate measuring device 114a and the No. 2 superheater flow rate measuring device 114b so as to communicate with each other. The control device 400 is communicably connected to opening degree measuring devices 109a and 111a that measure the opening degree of the second adjusting valve 109 and the third adjusting valve 111, respectively. And this control apparatus 400 receives the information of the steam pressure from the pressure measuring instrument 112, receives the information regarding the trip of each gas turbine type power generator 300a, 300b from each trip detector 113a, 113b, and each flow measuring instrument 114a, 114b. Information on the flow rate of the steam flowing into each superheater 104a, 104b is received, and information on each opening degree of the second regulating valve 109 and the third regulating valve 111 is received from each opening degree measuring instrument 109a, 111a.

  The control device 400 is communicably connected to the No. 1 superheater cutoff valve 106a, the No. 2 superheater cutoff valve 106b, the turbine bypass cutoff valve 108, the second adjustment valve 109, and the third adjustment valve 111. The control device 400 outputs an opening / closing operation signal to each of the shut-off valves 106a, 106b, 108, and outputs an opening operation signal to each of the adjusting valves 109, 111, respectively.

  Next, a control method for continuing the operation of the steam turbine power generator 200 when one of the two gas turbine power generators 300a and 300b having substantially the same capacity trips will be described.

  First, during normal operation, that is, when the No. 1 gas turbine power generator 300a and the No. 2 gas turbine power generator 300b are respectively operated, the No. 1 superheater shut-off valve 106a and the No. 2 superheater shut-off valve 106b are 1 In order to allow steam to flow into the No. 2 superheater 104a and the No. 2 superheater 104b, respectively, they are opened. At this time, the turbine bypass shut-off valve 108 is closed in order not to let the steam flow out to the turbine bypass conduit 107. The third regulating valve 111 is closed so that steam that is not overheated is not supplied to the steam turbine 201 through the superheater bypass line 110. When one of the two gas turbine generators 300a and 300b trips and the turbine bypass shut-off valve 108 is opened, the second regulating valve 109 causes steam to flow into the turbine bypass conduit 107 at a predetermined flow rate G1 described later. In this way, the opening degree is adjusted.

  More specifically, in this case, since the maximum value of the steam flow rate that can be passed through each of the No. 1 superheater 104a and the No. 2 superheater 104b is almost the same, the control device 400 uses Equation (1). Then, the steam flow rate G1 to be passed through the turbine bypass pipe 107 is calculated.

G1 = (G2 + G3) -G4 (1)
Here, G2 is a measured value of the steam flow rate flowing into the No. 1 superheater 104a immediately before the gas turbine power generator trips, and G3 is a No. 2 superheater 104b just before the gas turbine power generator trips. The measured value of the flow rate of the steam flowing into the tank, G4, is the maximum value of the steam flow rate that can flow into the superheaters 104a and 104b.

  Thereafter, the control device 400 calculates the opening degree of the second adjustment valve 109 based on the steam flow rate G1, and adjusts the opening degree of the second adjustment valve 109 so as to be this opening degree. This adjustment is performed in real time in response to changes in the flow rate of steam flowing into the No. 1 superheater 104a and the No. 2 superheater 104b. Of course, as will be described later, the steam flow rate G1 is calculated at the same time when the gas turbine power generator trips, and the opening degree of the second regulating valve 109 is calculated based on the steam flow rate. 2 You may adjust the opening degree of the adjustment valve 109.

  Here, the capacities of the two gas turbine power generators are substantially the same, but the present invention is not limited to this. For example, if the capacities of two gas turbine generators are not the same, or if three or more gas turbine generators are installed, it is not possible to know how many gas turbine generators will trip. (2) can be used to calculate the steam flow rate G5 that should flow through the turbine bypass pipe 107.

G5 = (G6 + G7 + G8 ...)-(G9 + G10 + ...) (2)
Here, G6, G7, G8... Are measured values of the flow rate of the steam flowing into each superheater immediately before the gas turbine power generator trips, and G9, G10. It is the maximum value of the steam flow rate that can flow into each superheater on the side.

  Thereafter, similarly to the above, the control device 400 calculates the opening degree of the second adjustment valve 109 based on the steam flow rate G5, and adjusts the opening degree of the second adjustment valve 109 so as to be this opening degree. By the way, in this case, since the opening degree of the second regulating valve 109 is not controlled before the gas turbine power generator trips, the turbine bypass cutoff valve 108 can be omitted. This simplifies the equipment.

  When either No. 1 gas turbine type power generator 300a or No. 2 gas turbine type power generator 300b trips from such a state, for example, when No. 1 gas turbine type power generator 300a trips, trip for No. 1 gas turbine The detector 113a detects this trip. The control device 400 receives trip information from the No. 1 gas turbine trip detector 113a. Based on this trip information, the control device 400 closes the No. 1 superheater shut-off valve 106a. At the same time, the turbine bypass shutoff valve 108 is opened. At this time, the second regulating valve 109 maintains the opening when the No. 1 gas turbine power generator 300a trips. This opening is an opening corresponding to the steam flow rate G1 calculated by the above equation (1).

  By this operation, the steam that has flowed into the No. 1 superheater 104a on the No. 1 gas turbine power generator 300a side that has tripped is shut off (blocking step). The steam shut off at the same time is transferred to the turbine bypass pipe 107 and the No. 2 superheater 104b on the side of the No. 2 gas turbine power generation device 300b that is in operation (first transition step). At this time, steam having a flow rate G1 flows into the turbine bypass conduit 107. As a result, since the steam having a flow rate that can be overheated flows through the No. 2 superheater 104b, the outlet steam temperature of the No. 2 heater 104b, that is, the inlet steam temperature of the steam turbine 201 does not rapidly decrease. Thereby, the change of the inlet steam temperature of the steam turbine 201 can be suppressed within an allowable range, and the operation of the steam turbine power generator 200 can be continued.

  After a predetermined time has elapsed after performing the above operation, the second adjustment valve 109 is gradually closed to be fully closed. At the same time, the steam in the turbine bypass pipe 107 is gradually transferred to the superheater bypass pipe 110 by gradually opening the third adjustment valve 111 (second transition process).

  At this time, as a method of gradually opening the third adjustment valve 111, for example, feedback control that operates the third adjustment valve 111 so that the steam pressure in the sump tank 103 substantially matches a preset target value may be adopted. good. More specifically, when the second adjustment valve 109 is gradually closed, the flow rate of the steam flowing out from the sump tank 103 decreases, so that the steam pressure in the sump tank 103 increases. And when this steam pressure exceeds a target value, in order to make this steam pressure substantially coincide with the target value, an operation of increasing the flow rate of the steam flowing out of the steam reservoir tank 103 by opening the third adjustment valve 111 is performed.

  Further, the speed at which the second regulating valve 109 is gradually closed is set so that the change in the inlet steam temperature of the steam turbine 201 falls within an allowable range. More specifically, for example, a temperature measuring device (not shown) for measuring the inlet steam temperature of the steam turbine 201 is provided in the steam supply pipe line 102 and connected to the control device 400 so as to be communicable. Then, a change in the inlet steam temperature of the steam turbine 201 is calculated based on the temperature information obtained from the temperature measuring instrument, and the second regulating valve 109 is closed so that the change falls within an allowable range.

  As described above, the steam discharged to the steam condenser 204 through the turbine bypass pipe 107 is transferred to the superheater bypass pipe 110, whereby the inlet steam flow rate of the steam turbine 201 is changed to No. 1 gas turbine power generator. The steam flow before 300a trips can be restored. By the way, since the steam passing through the superheater bypass pipe 110 is not superheated by the superheater, it is at a lower temperature than the steam superheated by the superheater, but the flow rate of steam passing through the superheater bypass pipe 110 is gradually increased. Therefore, the change in the inlet steam temperature of the steam turbine 201 can be controlled within an allowable range. As a result, the operation of the steam turbine power generator 200 can be continued.

Hereinafter, it explains in full detail based on an Example.
〔Example〕
As shown in FIG. 1, the combined power plant according to the embodiment includes a waste incinerator 100, a steam turbine power generator 200, a No. 1 gas turbine power generator 300a, a No. 2 gas turbine power generator 300b, And a control device 400 for controlling these devices. The No. 1 gas turbine type power generation device 300a and the No. 2 gas turbine type power generation device 300b have substantially the same capacity, and there are auxiliary facilities such as superheaters 104a and 104b corresponding to the respective gas turbine type power generation devices 300a and 300b. Has almost the same ability.
[Operation results and evaluation]
FIG. 2 is a graph showing the operating state of the combined power plant when the No. 1 gas turbine type power generator trips in 300 seconds, (a) shows the change over time in the steam flow rate of the No. 1 superheater, b) shows the change over time of the steam flow rate of the No. 2 superheater, (c) shows the change over time of the steam flow rate in the turbine bypass line, and (d) shows the change over time of the steam flow rate in the superheater bypass line. (E) shows the change with time of the steam temperature at the inlet of the steam turbine, and (f) shows the change with time of the steam flow rate at the inlet of the steam turbine.

  As shown in FIGS. 2 (a) and 2 (b), approximately 30th of steam flows through the No. 1 superheater 104a and approximately 30t / h of steam flows through the No. 2 superheater 104b before 300 seconds. . These correspond to G2 and G3 in the formula (1), respectively.

  When the No. 1 gas turbine power generator 300a trips at 300 seconds, the No. 1 superheater shut-off valve 106a is closed, so that the steam flow rate of the No. 1 superheater 104a is 30 t / s as shown in FIG. From h to 0 t / h. At the same time, by opening the turbine bypass shut-off valve 108, as shown in FIG. 2C, about 20 t / h of the steam (30 t / h) shut off in the turbine bypass pipe 107 flows. This flow rate corresponds to the vapor flow rate G1 calculated from the equation (1). And the opening degree of the 2nd regulating valve 109 is controlled so that it may become this flow. On the other hand, of the blocked steam (30 t / h), the remaining steam (about 10 t / h) is added to the steam (30 t / h) flowing through the No. 2 superheater 104b. As a result, as shown in FIG. 2B, about 40 t / h of steam flows through the No. 2 superheater 104b. This steam flow rate corresponds to G4 in the equation (1).

  Thereafter, by gradually opening the third regulating valve 111 from time 550 seconds, the flow rate of steam passing through the superheater bypass pipe 110 gradually increases as shown in FIG. It becomes about 30 t / h which is the same as the shut-off steam flow rate. At the same time, by gradually closing the second adjustment valve 109, as shown in FIG. 2 (c), the flow rate of the steam passing through the turbine bypass pipe 107 is gradually reduced to about 0 t / h in the vicinity of 700 seconds. Become.

  By the above operation, as shown in FIG. 2 (e), the inlet steam temperature of the steam turbine 201 hardly changes during the time of 300 to 550 seconds, and from 430 ° C. to 380 ° C. during the time of 550 to 700 seconds. It is gradually descending. Thus, the change in the inlet steam temperature of the steam turbine 201 is suppressed within an allowable range. Further, as shown in FIG. 2 (f), the inlet steam flow rate of the steam turbine 201 decreases immediately after the No. 1 gas turbine power generator 300a trips. The steam flow rate (approximately 30 t / h) before the power generator 300a trips is gradually restored.

  As described above, according to this embodiment, it is possible to prevent the steam temperature at the inlet of the steam turbine from changing suddenly and to continue the operation of the steam turbine power generator 200. At the same time, the inlet steam flow rate of the steam turbine 201 can be returned to the flow rate before the gas turbine power generator trips, and a significant decrease in the amount of power generation can be suppressed.

  The above-described embodiment is an example, and various modifications can be made without departing from the spirit of the present invention, and the present invention is not limited to the above-described embodiment.

It is a flowchart which shows the structure of the combined power plant which concerns on one Embodiment of this invention. It is a graph which shows the driving | running state of a combined power plant when a No. 1 gas turbine type power generating device trips in 300 seconds, (a) shows change with time of the steam flow of No. 1 superheater, (b) is 2 (C) shows the change over time in the steam flow in the turbine bypass line, (d) shows the change over time in the steam flow in the superheater bypass line, e) shows the change with time of the inlet steam temperature of the steam turbine, and (f) shows the change with time of the inlet steam flow rate of the steam turbine.

Explanation of symbols

100 ... Waste incinerator
101 ... Waste heat boiler
102 ... Steam supply line
103 ... Steam reservoir tank
104a, 104b ... No. 1 superheater, No. 2 superheater
105a, 105b ... No.1 superheater branch pipe, No.2 superheater branch pipe
106a, 106b ... No.1 superheater shutoff valve, No.2 superheater shutoff valve
107: Turbine bypass pipeline
108: Turbine bypass shut-off valve
109 ... Second adjustment valve
110 ... Superheater bypass line
111 ... Third adjustment valve
113a ... Trip detector for No. 1 gas turbine (trip detection means)
113b ... No. 2 gas turbine trip detector (trip detection means)
200 ... Steam turbine power generator
201 ... steam turbine
300 ... Gas turbine type power generator
301a, 301b ... No. 1 gas turbine, No. 2 gas turbine
400 ... Control device

Claims (8)

A plurality of gas turbine power generators;
A steam generator for generating steam;
A superheater that is provided on the exhaust side of each gas turbine and superheats the steam generated in the steam generator by the exhaust gas discharged from each gas turbine;
A steam turbine power generator driven by superheated steam superheated in each superheater;
Shut-off means for shutting off the steam flowing into each superheater;
Trip detection means provided for each gas turbine power generator, respectively, for detecting a trip of each gas turbine power generator;
A control device for controlling the operation of the combined power plant,
When the control device obtains information on a trip of a part of the plurality of gas turbine power generators from the trip detection means, the gas turbine power generator that has tripped based on this information is obtained. A combined power plant configured to shut off a shut-off means corresponding to an apparatus-side superheater. A turbine bypass passage that bypasses the gas turbine power generator and the steam turbine power generator by communicating the outlet side passage of the steam generator and the outlet side passage of the steam turbine;
A first flow rate adjusting means for adjusting a steam flow rate in the turbine bypass passage interposed in the middle of the turbine bypass passage;
The control device shuts off the shut-off means and controls the opening of the first flow rate adjusting means, whereby a part or all of the steam shut off by the shut-off means passes through the turbine bypass passage and is connected to the outlet side passage of the steam turbine. The combined power plant according to claim 1, wherein the combined power plant is configured to discharge to the outside. It further comprises a flow rate measuring means for measuring the flow rate of steam flowing into each superheater,
The control device calculates the flow rate of steam to be discharged to the outlet side passage of the steam turbine through the turbine bypass passage based on the flow rate information related to the steam flow rate obtained from the flow rate measuring means, and based on the calculated flow rate, The combined power plant according to claim 2, wherein the combined power plant is configured to control an opening degree of the first flow rate adjusting means. A superheater bypass passage that bypasses the superheater by communicating the outlet side passage of the steam generator and the outlet side passage of the superheater;
And a second flow rate adjusting means for adjusting the steam flow rate in the superheater bypass passage interposed in the middle of the superheater bypass passage,
The control device gradually decreases the opening degree of the first flow rate adjusting means and gradually increases the opening degree of the second flow rate adjusting means after a predetermined time has elapsed from when the steam is transferred to the turbine bypass passage. The combined power plant according to claim 2 or 3, wherein the steam in the turbine bypass passage is transferred to the superheater bypass passage and supplied to the steam turbine. Pressure measuring means for measuring the pressure of the steam upstream of the first flow rate adjusting means,
When the steam of the turbine bypass passage is transferred to the superheater bypass passage, the control device gradually decreases the opening of the first flow rate adjusting means and relates to the pressure of the steam obtained from the pressure measuring means. The combined power plant according to claim 4, wherein the opening degree of the second flow rate adjusting means is controlled so that the pressure becomes a preset target value based on the information. A plurality of gas turbine generators, a steam generator for generating steam, and an exhaust gas discharged from each gas turbine provided on the exhaust side of each gas turbine are used to superheat the steam generated in the steam generator. Superheater, steam turbine power generator driven by superheated steam superheated by each superheater, shut-off means for shutting off steam flowing into each superheater, and trip detection of each gas turbine power generator A control method applied to a combined power plant comprising trip detecting means for
When the trip detection means detects that a part of the gas turbine type power generators of the plurality of gas turbine type power generators have tripped, the tripping means trips to the superheater on the gas turbine type power generator side where the trip means has tripped. A control method for a combined power plant, comprising a shut-off process for shutting off inflowing steam. A plurality of gas turbine power generators, a steam generator for generating steam, and an overheat that superheats steam generated in the steam generator by exhaust gas discharged from each gas turbine provided on the exhaust side of each gas turbine. , Steam turbine power generator driven by superheated steam superheated by each superheater, shut-off means for shutting off the steam flowing into each superheater, and detecting trip of each gas turbine power generator A control method applied to a combined power plant comprising trip detection means and a turbine bypass passage communicating the outlet side passage of the steam generator and the outlet side passage of the steam turbine,
When the trip detection means detects that a part of the gas turbine type power generators of the plurality of gas turbine type power generators have tripped, the tripping means trips to the superheater on the gas turbine type power generator side where the trip means has tripped. A shut-off process for shutting off the inflowing steam;
A control method for a combined power plant, comprising: a first transition step in which the steam blocked by the blocking means is transferred to the turbine bypass passage and the superheater on the side of the gas turbine power generator that is operating continuously. A plurality of gas turbine power generators, a steam generator for generating steam, and an overheat that superheats steam generated in the steam generator by exhaust gas discharged from each gas turbine provided on the exhaust side of each gas turbine. , Steam turbine power generator driven by superheated steam superheated by each superheater, shut-off means for shutting off the steam flowing into each superheater, and detecting trip of each gas turbine power generator Trip detection means, turbine bypass passage communicating the outlet side passage of the steam generator and the outlet side passage of the steam turbine, superheater bypass passage communicating the outlet side passage of the steam generator and the outlet side passage of the superheater A control method applied to a combined power plant comprising:
When the trip detection means detects that a part of the gas turbine type power generators of the plurality of gas turbine type power generators have tripped, the tripping means trips to the superheater on the gas turbine type power generator side where the trip means has tripped. A shut-off process for shutting off the inflowing steam;
A first transition step of transitioning the steam blocked by the blocking means to the turbine bypass passage and the superheater on the side of the gas turbine power generator that is operating;
And a second transition step of gradually transitioning the steam transferred to the turbine bypass passage to the superheater bypass passage after elapse of a predetermined time from when the steam is transferred to the turbine bypass passage.

Images