Waste heat recovery boiler system, control method for waste heat recovery boiler system, program

Abstract

Reduce plant startup time. [Solution] The control method for the waste heat recovery boiler system includes the step of receiving input of a start command for the combined plant, and when the input of the start command is received, operating the low-pressure feedwater pump and the medium- and high-pressure feedwater pump to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel.

Description

Technical Field

[0001] The present disclosure relates to an exhaust heat recovery boiler system, a control method for an exhaust heat recovery boiler system, and a program.

Background Art

[0002] A combined plant equipped with a steam turbine and a prime mover such as a gas turbine includes a heat recovery steam generator (HRSG). The heat recovery steam generator generates steam used in the steam turbine by the heat contained in the exhaust gas from the prime mover. Patent Document 1 discloses a heat recovery boiler provided with a fuel economizer that heats feed water using exhaust gas, a steam drum into which the feed water heated by the fuel economizer flows, and an evaporator connected to the steam drum, in each of a high-pressure system, a medium-pressure system, and a low-pressure system.

[0003] In such a heat recovery boiler, at the time of starting the combined plant, it is necessary to pre-fill water in the steam drum and the fuel economizer of the heat recovery boiler. For this reason, Patent Document 1 describes a configuration in which water filling is performed in the order of the high-pressure system, the medium-pressure system, and the low-pressure system. Also, at the time of starting the combined plant, water filling is sometimes performed in the order of the low-pressure system, the medium-pressure system, and the high-pressure system.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the configuration in which water filling is sequentially performed in the high-pressure system, the medium-pressure system, and the low-pressure system as described in Patent Document 1, it takes a long time to fill water in a steam drum having a particularly large capacity, which has been an obstacle to shortening the startup time of the combined plant.

[0006] This disclosure was made to solve the above-mentioned problems and aims to provide a waste heat recovery boiler system, a control method for the waste heat recovery boiler system, and a program that can shorten the plant startup time. [Means for solving the problem]

[0007] To solve the above problems, the waste heat recovery boiler system according to the present disclosure is a waste heat recovery boiler system used in a combined plant, comprising: a low-pressure feedwater pump for supplying water; a low-pressure economizer for heating the water supplied from the low-pressure feedwater pump; a low-pressure steam drum connected to the low-pressure economizer via a low-pressure feedwater line; a medium-high pressure feedwater pump connected via a branch line branching from the low-pressure feedwater line for increasing the pressure of the water heated by the low-pressure economizer; a medium-pressure steam drum connected to the medium-high pressure feedwater pump via a medium-pressure feedwater line; and a device provided in the middle of the medium-pressure feedwater line for increasing the pressure of the medium-high pressure feedwater pump. The plant comprises a medium-pressure economizer for heating the supplied water, a high-pressure steam drum connected to the medium- and high-pressure feedwater pump via a high-pressure feedwater line, a high-pressure economizer installed in the middle of the high-pressure feedwater line for heating the water pressurized by the medium- and high-pressure feedwater pump, and a control device. The control device includes an information acquisition unit for receiving input of a start command for the combined plant, and a control unit that, upon receiving input of a start command for the combined plant, operates the low-pressure feedwater pump and the medium- and high-pressure feedwater pump to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel.

[0008] The control method for a waste heat recovery boiler system according to this disclosure is a control method for a waste heat recovery boiler system as described above, and includes the steps of: receiving input of a start command for the combined plant; and, upon receiving input of the start command, operating the low-pressure feedwater pump and the medium- and high-pressure feedwater pump to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel.

[0009] The program relating to this disclosure causes the control device of the waste heat recovery boiler system described above to execute a process that includes the steps of receiving input of a start command for the combined plant, and, upon receiving input of the start command, operating the low-pressure feedwater pump and the medium- and high-pressure feedwater pump to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel. [Effects of the Invention]

[0010] According to the waste heat recovery boiler system, control method for the waste heat recovery boiler system, and program of this disclosure, plant startup time can be shortened. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows the configuration of a waste heat recovery boiler system according to an embodiment of the present disclosure. [Figure 2] This figure shows the hardware configuration of a control device according to an embodiment of the present disclosure. [Figure 3] This figure shows the functional configuration of a control device according to an embodiment of the present disclosure. [Figure 4] This flowchart shows the procedure for a control method of a waste heat recovery boiler system according to an embodiment of the present disclosure. [Figure 5] This figure shows a state in which water is being supplied in parallel to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in a waste heat recovery boiler system according to an embodiment of the present disclosure. [Figure 6] This figure shows the state in which the water supply to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum is stopped in the waste heat recovery boiler system according to the embodiment of this disclosure. [Modes for carrying out the invention]

[0012] The following describes, with reference to the attached drawings, the heat recovery boiler system, the control method for the heat recovery boiler system, and the embodiments for implementing the program according to this disclosure. However, this disclosure is not limited to these embodiments. (Configuration of a waste heat recovery boiler system) As shown in Figure 1, the waste heat recovery boiler system 1 mainly comprises a low-pressure feedwater pump 10, a low-pressure economizer 11, a low-pressure steam drum 12, a medium- and high-pressure feedwater pump 13, a medium-pressure steam drum 14, a medium-pressure economizer 15, a high-pressure steam drum 16, a high-pressure economizer 17, and a control device 2. Such a waste heat recovery boiler system 1 is installed in a combined plant 5 equipped with a steam turbine (not shown) and a gas turbine (not shown). The waste heat recovery boiler system 1 generates steam using waste heat from the gas turbine. The steam generated by the waste heat recovery boiler system 1 is supplied to the steam turbine to drive the steam turbine. Hereinafter, the configuration of the combined plant 5 equipped with the waste heat recovery boiler system 1 in this embodiment is not limited in any way.

[0013] The low-pressure feedwater pump 10 supplies water from the condenser 3, which condenses steam that has passed through the steam turbine of the combined plant 5, to the low-pressure economizer 11. The condenser 3 and the low-pressure economizer 11 are connected via a feedwater line 101. The low-pressure feedwater pump 10 is installed in the middle of the feedwater line 101.

[0014] The low-pressure economizer 11 heats the water supplied from the condenser 3 through the feed line 101 by the low-pressure feedwater pump 10 through heat exchange with the waste heat from the gas turbine (not shown).

[0015] The low-pressure economizer 11 is connected to the low-pressure steam drum 12 via a low-pressure water supply line 102. The low-pressure steam drum 12 stores the water heated in the low-pressure economizer 11. An on-off valve 102v is provided in the middle of the low-pressure water supply line 102, and by opening and closing the on-off valve 102v, the supply of water from the low-pressure economizer 11 to the low-pressure steam drum 12 can be intermittently controlled. The water in the low-pressure steam drum 12 is connected to a steam turbine (low-pressure steam turbine: not shown) via a low-pressure steam supply line 103. An evaporator (not shown) is provided in the middle of the low-pressure steam supply line 103 to evaporate the water from the low-pressure steam drum 12 and generate steam. The generated steam is fed to the steam turbine through the low-pressure steam supply line 103.

[0016] The medium-high pressure feed water pump 13 is connected to the low-pressure economizer 11 via a branch line 104 branching from the low-pressure feed water line 102. The branch line 104 branches from a portion between the low-pressure economizer 11 and the on-off valve 102v in the low-pressure feed water line 102 and is connected to the medium-high pressure feed water pump 13. The medium-high pressure feed water pump 13 boosts the pressure of the water heated by the low-pressure economizer 11. In addition, the waste heat recovery boiler system 1 in this embodiment is provided with a bypass line 111 that bypasses the low-pressure economizer 11 and the low-pressure steam drum 12. One end of the bypass line 111 is connected to the feed water line 101 between the low-pressure feed water pump 10 and the low-pressure economizer 11. The other end of the bypass line 111 is connected to the branch line 104. The bypass line 111 bypasses the low-pressure economizer 11 and the low-pressure steam drum 12 and connects the low-pressure feed water pump 10 and the medium-high pressure feed water pump 13. A low-pressure economizer bypass valve 111v is provided in the middle of the bypass line 111.

[0017] A medium-pressure feed water line 105 and a high-pressure feed water line 106 are connected to the medium-high pressure feed water pump 13. That is, the water pressurized by the medium-high pressure feed water pump 13 branches and is fed to the medium-pressure feed water line 105 and the high-pressure feed water line 106.

[0018] The medium-pressure steam drum 14 is connected to the medium-high pressure feed water pump 13 via the medium-pressure feed water line 105. A medium-pressure economizer 15 is provided in the middle of the medium-pressure feed water line 105. The medium-pressure economizer 15 heats the water pressurized by the medium-high pressure feed water pump 13 through heat exchange with the waste heat from a gas turbine (not shown).

[0019] The medium-pressure steam drum 14 stores water heated by the medium-pressure economizer 15. An on-off valve 105v is provided in the middle of the medium-pressure feed water line 105. By opening and closing the on-off valve 105v, the feeding of water from the medium-pressure economizer 15 to the medium-pressure steam drum 14 can be intermittent.

[0020] The water in the medium-pressure steam drum 14 is connected to a steam turbine (medium-pressure steam turbine: not shown) via the medium-pressure steam supply line 108. An evaporator (not shown) is provided in the middle of the medium-pressure steam supply line 108 to evaporate the water from the medium-pressure steam drum 14 to generate steam. The generated steam is fed to the steam turbine through the medium-pressure steam supply line 108.

[0021] The high-pressure steam drum 16 is connected to the medium-high pressure feed water pump 13 via the high-pressure feed water line 106. A high-pressure economizer 17 is provided in the middle of the high-pressure feed water line 106. The high-pressure economizer 17 heats the water pressurized by the medium-high pressure feed water pump 13 by heat exchange with the exhaust heat from a gas turbine (not shown).

[0022] The high-pressure steam drum 16 stores water heated by the high-pressure economizer 17. An on-off valve 106v is provided in the middle of the high-pressure feed water line 106. By opening and closing the on-off valve 106v, the feeding of water from the high-pressure economizer 17 to the high-pressure steam drum 16 can be intermittent.

[0023] The water in the high-pressure steam drum 16 is connected to a steam turbine (high-pressure steam turbine: not shown) via the high-pressure steam supply line 109. An evaporator (not shown) is provided in the middle of the high-pressure steam supply line 109 to evaporate the water from the high-pressure steam drum 16 to generate steam. The generated steam is fed to the steam turbine through the high-pressure steam supply line 109.

[0024] Each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 is equipped with liquid level gauges 12s, 14s, and 16s that detect the feed water levels (liquid levels) of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16.

[0025] (Control device configuration) Figure 2 is a diagram showing the hardware configuration of a control device according to an embodiment of the present disclosure. The functions of the control device 2 will be described in detail below. As shown in Figure 2, the control device 2 is a computer equipped with a processor 61 such as a CPU (Central Processing Unit), ROM 62 (Read Only Memory), RAM 63 (Random Access Memory), storage 64, and a signal transmission / reception module 65.

[0026] The processor 61 is responsible for controlling the overall operation of the control device 2. The various functions of the processor 61 will be described later.

[0027] The signal transmission / reception module 65 is a communication interface for communicating with the higher-level computer that controls the combined plant 5 and with the various parts of the waste heat recovery boiler system 1.

[0028] Figure 3 is a diagram showing the functional configuration of the control device according to the embodiment of this disclosure. As shown in Figure 3, the processor 61 functionally comprises an information acquisition unit 31 and a control unit 32 by operating based on a predetermined program. The predetermined program may be for realizing a part of the functions to be performed by the control device 2. For example, the program may perform its functions in combination with other programs already stored in the storage 64, or in combination with other programs implemented in other devices.

[0029] The information acquisition unit 31 acquires various information for controlling the waste heat recovery boiler system 1. It receives input from the higher-level computer that controls the entire combined plant 5, including start commands for starting the combined plant 5 and stop commands for stopping the combined plant 5. The information acquisition unit 31 also receives detection data of the feedwater levels in the low-pressure steam drum 12, medium-pressure steam drum 14, and high-pressure steam drum 16 from the liquid level gauges 12s, 14s, and 16s.

[0030] Based on the information acquired by the information acquisition unit 31, the control unit 32 controls the water supply operation to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in the waste heat recovery boiler system 1. In this embodiment, when the control unit 32 receives a start command input for the combined plant 5, it activates the low-pressure feedwater pump 10 and the medium- and high-pressure feedwater pump 13 to supply water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0031] (Procedure for controlling a waste heat recovery boiler system) Figure 4 is a flowchart showing the procedure for a control method of a waste heat recovery boiler system according to an embodiment of the present disclosure. As shown in Figure 4, the control method S10 of the waste heat recovery boiler system 1 according to the embodiment of this disclosure includes the steps of: receiving a start command input S11; supplying water S12; detecting the water supply level S13; stopping the water supply S14; receiving a stop command input S15; supplying water S16; detecting the water supply level S17; and stopping the water supply S18.

[0032] In step S11, which accepts the input of a startup command, the information acquisition unit 31 checks whether or not a startup command has been input from the higher-level computer that controls the entire complex plant 5 when starting up the complex plant 5. If a startup command for the complex plant 5 has been input (step S11: Yes), the information acquisition unit 31 accepts the input of the startup command. If no startup command has been input (step S11: No), step S11 is repeated at predetermined time intervals.

[0033] Figure 5 shows a state in which water is being supplied in parallel to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in a waste heat recovery boiler system according to an embodiment of the present disclosure. If a start command is received in step S11, in step S12, which involves supplying water, the control unit 32 opens the on-off valves 102v, 105v, and 106v as shown in Figure 5, and operates the low-pressure feedwater pump 10 and the medium-high pressure feedwater pump 13. At this time, the low-pressure economizer bypass valve 111v of the bypass line 111 is also opened. As a result, a portion of the water from the condenser 3, after passing through the low-pressure feedwater pump 10 and the low-pressure economizer 11, is supplied to the low-pressure steam drum 12 through the low-pressure feedwater line 102. The remaining water after passing through the low-pressure feedwater pump 10 and the low-pressure economizer 11 is pressurized by the medium-high pressure feedwater pump 13 and then branches off into the medium-pressure feedwater line 105 and the high-pressure feedwater line 106. In the medium-pressure feedwater line 105, the water after passing through the medium-high pressure feedwater pump 13 is heated by the medium-pressure economizer 15 and then supplied to the medium-pressure steam drum 14. In the high-pressure water supply line 106, water that has passed through the medium- and high-pressure water supply pump 13 is heated in the high-pressure economizer 17 before being supplied to the high-pressure steam drum 16. In this way, the supply of water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 is carried out in parallel.

[0034] In step S13, which detects the water supply level, after the start of water supply in step S12, the information acquisition unit 31 acquires the water supply levels (liquid levels) of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, as detected by the liquid level gauges 12s, 14s, and 16s. The control unit 32 determines whether the water supply levels in each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, as acquired by the information acquisition unit 31, have reached a first target level. Here, the first target level is set for the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, respectively.

[0035] Figure 6 shows the state in which the water supply to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum is stopped in the waste heat recovery boiler system according to the embodiment of this disclosure. Step S14 is executed when the feedwater level in each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 reaches the first target level set for each. In step S14, which stops the feedwater supply, as shown in Figure 6, when the feedwater level in each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 reaches the first target level set for each, the on-off valves 102v, 105v, and 106v are closed to stop the feedwater supply. Specifically, when the feedwater level in the low-pressure steam drum 12 reaches the first target level, the on-off valve 102v is closed. When the feedwater level in the medium-pressure steam drum 14 reaches the first target level, the on-off valve 105v is closed. When the feedwater level in the high-pressure steam drum 16 reaches the first target level, the on-off valve 106v is closed. When the feedwater level in all three—the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16—reaches the first target level, the low-pressure feedwater pump 10 and the medium- and high-pressure feedwater pump 13 are stopped. This completes the supply of water (filling) to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16. Subsequently, steam is generated using water supplied from the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, and the combined plant 5 is put into operation by starting the steam turbine.

[0036] In step S15, which accepts the input of a stop command, the information acquisition unit 31 checks whether or not a stop command has been input from the higher-level computer that controls the entire complex plant 5 when stopping the complex plant 5. If a stop command for the complex plant 5 has been input (step S15: Yes), the information acquisition unit 31 accepts the input of the stop command. If no stop command has been input (step S15: No), step S15 is repeated at predetermined time intervals.

[0037] If a stop command is received in step S15, step S16, which involves supplying water, is executed. In step S16, which involves supplying water, water is supplied to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in preparation for the evaporation of water in the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 while the combined plant 5 is stopped. To do this, the control unit 32 opens the on-off valves 102v, 105v, and 106v, and operates the low-pressure feedwater pump 10 and the medium-high pressure feedwater pump 13. As a result, in the same manner as in step S12, water is supplied to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0038] In step S17, which detects the water supply level, after the start of water supply in step S16, the information acquisition unit 31 acquires the water supply levels (liquid levels) of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 at liquid level gauges 12s, 14s, and 16s. The control unit 32 determines whether the water supply levels in each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, acquired by the information acquisition unit 31, have reached a second target level. Here, the second target level is set higher than the first target level. Note that the second target level may be the same as the first target level. The second target level is set for the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, respectively.

[0039] In step S18, which involves stopping the water supply, when the water supply level in each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 reaches the second target level set for each, the shut-off valves 102v, 105v, and 106v are closed to stop the water supply. When the water supply level in all of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 reaches the second target level, the low-pressure feedwater pump 10 and the medium-high pressure feedwater pump 13 are stopped. This completes the supply of replenishment water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in preparation for evaporation while the combined plant 5 is shut down. After this, the entire combined plant 5 is shut down.

[0040] Subsequently, the series of steps S11 to S18 are repeated in accordance with the startup and shutdown of the combined plant 5.

[0041] (Effects and Benefits) In the waste heat recovery boiler system 1 and control method S10 of the waste heat recovery boiler system 1 with the above configuration, the plant startup time can be shortened by supplying water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0042] Conventionally, after completing the water supply (water filling) to the low-pressure economizer 11 and the low-pressure steam drum 12, water was supplied to the intermediate-pressure steam drum 14 and the high-pressure steam drum 16 in sequence. In order to supply water to the intermediate-pressure steam drum 14 and the high-pressure steam drum 16, it is necessary to start the medium-high pressure feedwater pump 13 that supplies water to the intermediate-pressure steam drum 14 and the high-pressure steam drum 16. In order to start the medium-high pressure feedwater pump 13, it is necessary to stabilize the inlet pressure of the medium-high pressure feedwater pump 13 by completing the water supply to the low-pressure steam drum 12, using the pressure (water head) of the water stored in the low-pressure steam drum 12. For this reason, the inlet pressure of the medium-high pressure feedwater pump 13 was stabilized by completing the water supply to the low-pressure steam drum 12 and using the pressure of the water stored in the low-pressure steam drum 12. In contrast, the waste heat recovery boiler system 1 with the above configuration is provided with a bypass line 111 that bypasses the low-pressure economizer 11 and the low-pressure steam drum 12. Therefore, if the low-pressure economizer bypass valve 111v is opened, when the low-pressure feedwater pump 10 supplies water to the low-pressure steam drum 12, water is supplied from the low-pressure feedwater pump 10 to the inlet of the medium-high pressure feedwater pump 13 through the bypass line 111, increasing the inlet pressure of the medium-high pressure feedwater pump 13. As a result, the medium-high pressure feedwater pump 13 can be started to supply water to the medium-pressure steam drum 14 and to the high-pressure steam drum 16 in parallel.

[0043] Furthermore, according to the configuration of the above embodiment, when the water supply level to each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 reaches a first target level, the water supply is stopped. This makes it possible to supply a predetermined amount of water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0044] Furthermore, according to the configuration of the above embodiment, when the combined plant 5 is shut down, water is supplied to each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 up to a second target level, which is higher than the first target level. This makes it possible to store an amount of water that will be used to compensate for the decrease in water level inside the steam drums due to evaporation while the combined plant 5 is shut down.

[0045] (Modified version of the embodiment) In the above embodiment, when the combined steam plant 5 is stopped, in step S18, water is supplied to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 to a second target level in preparation for evaporation in the drums while the combined steam plant 5 is stopped. However, due to water evaporation while the combined steam plant 5 is stopped, the water supply levels in the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 may drop excessively when the combined steam plant 5 is restarted. Therefore, when a start command is received in step S11, the feedwater levels of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 may be checked before executing step S12, and water may be supplied to those whose feedwater levels have dropped excessively. Alternatively, while the combined plant 5 is shut down, the feedwater levels of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 may be checked periodically, and water may be supplied to those whose feedwater levels have dropped excessively. In this case, it is preferable to supply water up to a third target level, which is set lower than the first target level.

[0046] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.

[0047] Furthermore, a program to implement all or part of the functions of the control device 2 may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed to perform processing by each functional unit. Here, "computer system" includes hardware such as the OS and peripheral devices. Also, if a WWW system is used, "computer system" also includes the homepage provisioning environment (or display environment). Furthermore, "computer-readable recording medium" refers to portable media such as CDs, DVDs, USBs, and storage devices such as hard disks built into the computer system. In addition, if this program is distributed to the control device 2 via a communication line, the control device 2 that receives the program may unpack it into storage 64, etc., and execute the above processing. Furthermore, the above program may be for implementing only a part of the functions described above, and may also be able to implement the above functions in combination with a program already recorded in the computer system.

[0048] <Note> The waste heat recovery boiler system 1, the control method for the waste heat recovery boiler system 1, and the program described in the embodiment can be understood, for example, as follows.

[0049] (1) The waste heat recovery boiler system 1 according to the first embodiment is a waste heat recovery boiler system 1 used in a combined plant 5, comprising: a low-pressure feedwater pump 10 for supplying water; a low-pressure economizer 11 for heating the water supplied from the low-pressure feedwater pump 10; a low-pressure steam drum 12 connected to the low-pressure economizer 11 via a low-pressure feedwater line 102; a medium-high pressure feedwater pump 13 connected via a branch line 104 branching from the low-pressure feedwater line 102 for increasing the pressure of the water heated in the low-pressure economizer 11; a medium-pressure steam drum 14 connected to the medium-high pressure feedwater pump 13 via a medium-pressure feedwater line 105; and a pump provided in the middle of the medium-pressure feedwater line 105 for increasing the pressure of the water heated in the medium-high pressure feedwater pump 13 The complex plant 5 comprises an intermediate pressure economizer 15 for heating pressurized water, a high-pressure steam drum 16 connected to the intermediate-high pressure water supply pump 13 via a high-pressure water supply line 106, a high-pressure economizer 17 installed in the middle of the high-pressure water supply line 106 for heating water pressurized by the intermediate-high pressure water supply pump 13, and a control device 2, an information acquisition unit 31 for receiving input of a start command for the complex plant 5, and a control unit 32 that, upon receiving input of a start command for the complex plant 5, operates the low-pressure water supply pump 10 and the intermediate-high pressure water supply pump 13 to supply water to the low-pressure steam drum 12, the intermediate-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0050] This waste heat recovery boiler system 1 can shorten plant startup time by simultaneously supplying water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16.

[0051] (2) The waste heat recovery boiler system 1 according to the second embodiment is the waste heat recovery boiler system 1 of (1), further comprising a bypass line 111 that bypasses the low-pressure economizer 11 and the low-pressure steam drum 12 and connects the low-pressure feedwater pump 10 and the medium- and high-pressure feedwater pump 13.

[0052] As a result, when the low-pressure feedwater pump 10 supplies water to the low-pressure steam drum 12, water is supplied from the low-pressure feedwater pump 10 to the inlet of the medium- and high-pressure feedwater pump 13 through the bypass line 111, increasing the inlet pressure of the medium- and high-pressure feedwater pump 13. Consequently, it becomes possible to start the medium- and high-pressure feedwater pump 13 and supply water to the medium-pressure steam drum 14 and the high-pressure steam drum 16 in parallel.

[0053] (3) A control method for the waste heat recovery boiler system 1 according to the third embodiment is a control method for the waste heat recovery boiler system 1 according to (1) or (2), comprising: step S11 of receiving input of a start command for the combined plant 5; and step S12 of operating the low-pressure feedwater pump 10 and the medium- and high-pressure feedwater pump 13 when the input of the start command has been received, and supplying water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0054] This allows for the simultaneous supply of water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, thereby shortening the plant startup time.

[0055] (4) A control method for the waste heat recovery boiler system 1 according to a fourth embodiment is the control method for the waste heat recovery boiler system 1 according to (3), further comprising: a step S13 for detecting the feedwater level in each of the low-pressure steam drum 12, the intermediate-pressure steam drum 14, and the high-pressure steam drum 16; and a step S14 for stopping the feedwater supply to each of the low-pressure steam drum 12, the intermediate-pressure steam drum 14, and the high-pressure steam drum 16 when the feedwater level reaches a first target level set for each of the low-pressure steam drum 12, the intermediate-pressure steam drum 14, and the high-pressure steam drum 16.

[0056] With this configuration, the water supply to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 is stopped when the water supply level to each of them reaches a first target level. This allows for the supply of a predetermined amount of water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0057] (5) A control method for the waste heat recovery boiler system 1 according to the fifth embodiment is the control method for the waste heat recovery boiler system 1 according to (4), further comprising: step S15 of receiving input of a stop command for the combined plant 5; step S16 of operating the low-pressure feedwater pump 10 and the medium- and high-pressure feedwater pump 13 when the input of the stop command is received, to supply water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, respectively; and step S18 of stopping the supply of water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16, respectively, when the feedwater level reaches a second target level that is higher than the first target level set for each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16.

[0058] With this configuration, when the combined plant 5 is shut down, water is supplied to each of the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 up to a second target level, which is higher than the first target level. This allows for the storage of an amount of water that will be needed to compensate for the decrease in water level in the steam drums due to evaporation while the combined plant 5 is shut down.

[0059] (6) The program according to the sixth embodiment causes the control device 2 of the waste heat recovery boiler system 1 of (1) or (2) to execute a process including: step S11 of receiving input of a start command for the combined plant 5; and step S12 of operating the low-pressure feedwater pump 10 and the medium- and high-pressure feedwater pump 13 when the input of the start command is received, and supplying water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16 in parallel.

[0060] This allows the control device 2 to perform a process that shortens the plant startup time by simultaneously supplying water to the low-pressure steam drum 12, the medium-pressure steam drum 14, and the high-pressure steam drum 16. [Explanation of symbols]

[0061] 1…Waste heat recovery boiler system 2…Control device 3. Condenser 5…Combined plant 10... Low-pressure water supply pump 11... Low-pressure economizer 12... Low-pressure steam drum 12s, 14s, 16s…Liquid level gauge 13…Medium- and high-pressure water supply pump 14…Medium-pressure steam drum 15…Medium-pressure carbon reducer 16... High-pressure steam drum 17… High-pressure economizer 31…Information acquisition department 32…Control Unit 61… Processor 62...ROM 63...RAM 64... Storage 65...Signal transmission and reception module 101...Water supply line 102... Low-pressure water supply line 102V, 105V, 106V... Shut-off valves 103... Low-pressure steam supply line 104... Branch line 105...Medium-pressure water supply line 106... High-pressure water supply line 108...Medium-pressure steam supply line 109... High-pressure steam supply line 111... Bypass Line 111V... Bypass valve

Claims

1. A waste heat recovery boiler system used in a combined plant, A low-pressure water supply pump that delivers water, A low-pressure economizer that heats the water supplied from the low-pressure water supply pump, A low-pressure steam drum connected to the low-pressure economizer via a low-pressure water supply line, A medium-high pressure water supply pump is connected via a branch line that branches off from the low-pressure water supply line, and pressurizes the water heated by the low-pressure economizer. A medium-pressure steam drum connected to the aforementioned medium- and high-pressure water supply pump via a medium-pressure water supply line, A medium-pressure economizer is installed in the middle of the aforementioned medium-pressure water supply line and heats the water pressurized by the aforementioned medium- and high-pressure water supply pump, A high-pressure steam drum connected to the aforementioned medium- and high-pressure water supply pump via a high-pressure water supply line, A high-pressure economizer is installed in the middle of the aforementioned high-pressure water supply line and heats the water pressurized by the aforementioned medium- and high-pressure water supply pump, A control device is provided, The control device is An information acquisition unit that receives input for the startup command of the aforementioned complex plant, The system includes a control unit that, upon receiving a startup command for the combined plant, activates the low-pressure feedwater pump and the medium- and high-pressure feedwater pump to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel. Waste heat recovery boiler system.

2. The system further comprises a bypass line that bypasses the low-pressure economizer and the low-pressure steam drum, and connects the low-pressure feedwater pump and the medium- and high-pressure feedwater pump. The waste heat recovery boiler system according to claim 1.

3. A control method for a waste heat recovery boiler system according to claim 1 or 2, The steps include receiving input for a start command for the aforementioned combined plant, The process includes, upon receiving the aforementioned start command, activating the low-pressure feedwater pump and the medium- and high-pressure feedwater pump to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel. A control method for a waste heat recovery boiler system.

4. A step of detecting the feedwater level in each of the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum, The further step includes stopping the water supply to each of the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum when the water supply level reaches a first target level set for each of the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum, A control method for a waste heat recovery boiler system according to claim 3.

5. The steps include receiving input for a stop command for the aforementioned combined plant, When the stop command is received, the low-pressure feedwater pump and the medium- and high-pressure feedwater pump are activated to supply water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum, respectively. The step further includes stopping the water supply to each of the low-pressure steam drum, the intermediate-pressure steam drum, and the high-pressure steam drum when the water supply level reaches a second target level higher than the first target level set for each of the low-pressure steam drum, the intermediate-pressure steam drum, and the high-pressure steam drum, A control method for a waste heat recovery boiler system according to claim 4.

6. The control device of the waste heat recovery boiler system according to claim 1 or 2: The steps include receiving input for a start command for the aforementioned combined plant, When the input of the aforementioned start command is received, the system will execute a process that includes the step of operating the low-pressure feedwater pump and the medium- and high-pressure feedwater pump, and supplying water to the low-pressure steam drum, the medium-pressure steam drum, and the high-pressure steam drum in parallel. program.

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