JP2019152369A - Boiler system and control device of boiler system - Google Patents

Abstract

To enhance operating efficiency of an once-through boiler.SOLUTION: A control device of a boiler system comprising a first boiler (such as an exhaust gas boiler 112), a second boiler (such as an once-through boiler 121), and a header 130 into which steam generated by the exhaust gas boiler 112 and the once-through boiler 121 is introduced, comprises an once-through boiler operation restraining unit 140 for restraining operation of the once-through boiler 121 depending on at least one of an opening degree of a bypass damper 115 for bypassing exhaust gas to be introduced into the exhaust gas boiler 112, and an opening degree of a steam release valve 116 for releasing the steam of the header 130.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a boiler system having an exhaust gas boiler and a once-through boiler.

  As a boiler system, a boiler system having an exhaust gas boiler that generates steam using exhaust gas generated by a gas turbine and a plurality of once-through boilers that supplement generation of steam by the exhaust gas boiler is known (for example, see Patent Document 1). ). In such a boiler system, when the generated steam is reduced, the number of through-flow boilers according to the degree of the reduction is put into an operating state, so that the generated steam is increased.

JP 2000-274211 A

As a result of observing the operation state of the boiler system as described above in detail, the present inventors have realized that depending on the operation state, each once-through boiler frequently repeats operation, stop, and (start / stop). . In this case, for example, the operating efficiency of the once-through boiler is reduced, and the raw fuel consumption is increased. In view of the above points, the present invention can improve the operation efficiency of the once-through boiler and save energy. The purpose is to be.

In order to achieve the above object, the present invention provides:
A boiler system control device having a first boiler, a second boiler which is a once-through boiler, and a header into which steam generated by the first boiler and the second boiler is introduced,
A second boiler operation that suppresses the operation of the second boiler according to at least one of the degree of restriction of the amount of heat introduced into the first boiler and the opening of the evaporating valve that discharges the steam of the header. A suppression unit is provided.

   Thereby, for example, when the degree of restriction of the amount of heat introduced into the first boiler is greater than or equal to a predetermined level, the second boiler is prevented from being inadvertently operated by suppressing the stage increase control. Can be easily done.

  ADVANTAGE OF THE INVENTION According to this invention, the operating efficiency of a once-through boiler can be improved, energy saving etc. can be aimed at.

It is a block diagram which shows the structure of the boiler system of embodiment. It is a graph which shows the bypass damper opening degree control example of an exhaust gas boiler. It is a graph which shows the example of unit control of a once-through boiler. It is a flowchart which shows the control operation of a boiler system. It is a graph which shows the typical example of the control content of a boiler system.

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

(Boiler system configuration)
As shown in FIG. 1, the boiler system is provided with an exhaust gas boiler device 110 and a plurality of once-through boiler devices 120. Steam generated by these is supplied to the load via the header 130.

  The exhaust gas boiler device 110 includes a GE / GT 111 (gas engine / gas turbine), an exhaust gas boiler 112, an exhaust gas boiler pressure gauge 113, a valve opening control unit 114, and a bypass damper 115. The GE / GT 111 is used for generating steam by generating power with, for example, a gas engine or a gas turbine and introducing the exhaust gas into the exhaust gas boiler 112. The GE / GT 111 and the exhaust gas boiler 112 constitute, for example, a CGS (cogeneration system). The exhaust gas boiler pressure gauge 113 detects the steam pressure P <b> 1 near the outlet of the exhaust gas boiler 112. For example, as shown in FIG. 2, the valve opening control unit 114 controls the amount of exhaust gas introduced from the GE / GT 111 to the exhaust gas boiler 112 by controlling the opening degree of the bypass damper 115 according to the pressure P1. It is like that.

  On the other hand, the once-through boiler device 120 includes a once-through boiler 121 and a once-through boiler unit control unit 122. The once-through boiler 121 is detected by a header pressure gauge 131, for example, as shown in FIG. 3, when the generated steam of the exhaust gas boiler 112 decreases or when the use of steam on the secondary side increases and the load increases. The number of once-through boilers 121 corresponding to the pressure (pressure drop) of the header 130 is operated to generate steam and supply it.

  The header 130 supplies steam generated by the exhaust gas boiler device 110 and the once-through boiler device 120 to the load. The header 130 is provided with, for example, a steaming valve 116 so that the above can be discharged in accordance with the pressure of the steam inside the header 130 or the pressure P1 of the steam near the outlet of the exhaust gas boiler 112. .

  The once-through boiler operation suppression unit 140 is, for example, described in detail below based on the opening detected by a sensor (not shown) of the bypass damper 115 of the exhaust gas boiler device 110 and the pressure P2 of the header 130 detected by the header pressure gauge 131. As described above, when the pressure drop in the header 130 is temporary and sufficient steam is expected to be supplied from the exhaust gas boiler 112 within an allowable range, the operation of the once-through boiler 121 is suppressed. It has become.

(Operation of boiler system)
Hereinafter, an example of a control operation performed by the once-through boiler operation suppressing unit 140 in the boiler system as described above will be described with reference to FIGS. 4 and 5.

  (S101) First, it is determined whether or not the setting for performing the operation suppression control of the once-through boiler 121 is made according to the opening degree of the bypass damper 115 or the like. In other words, the suppression control function as described below may be constantly operated, but the degree of freedom of control can be increased by enabling such a function to be turned ON / OFF. When the operation suppression control is not performed, the process proceeds to (S107), and a unit control instruction is given to the once-through boiler unit control unit 122. Under the control of the once-through boiler unit control unit 122, t0 to t5 in FIG. As shown in the period, the number of operating once-through boilers 121 according to the pressure of the header 130 is controlled. More specifically, for example, when the header pressure P2 falls below a predetermined reference value C at time t1, the number of once-through boilers 121 corresponding to the pressure drop is operated. Eventually, when the header pressure P2 recovers to the reference value C (Pa) at time t2, all the once-through boilers 121 are stopped. Similarly, the number of once-through boilers 121 corresponding to the header pressure P2 is also operated during the period from t2 to t3.

  When it determines with (YES) by said (S101), ie, when suppression control of the once-through boiler 121 is performed, a process transfers to (S102, S103), and shows it in the period of t5-t11 of FIG. Such an operation is performed. Here, the header pressure P2 and the bypass damper opening are not necessarily changed in the same manner if the control normally performed is different between the period from t0 to t5 and the period from t5 to t11. In order to explain the relationship with the number of operating once-through boilers 121 in an easy-to-understand manner, it is assumed that they change in the same way.

  (S102, S103) It is determined whether the GE / GT 111 is in operation and there is no information indicating that the GE / GT 111 is out of order. If these determinations are (NO), the processing is performed as described above. The process proceeds to (S107), where the number control instruction is given to the once-through boiler unit control unit 122, and the number of operating units of the once-through boiler 121 is controlled. That is, when the GE / GT 111 is not in operation or has failed, the increase in steam by the exhaust gas boiler 112 cannot be expected, so control is performed so as to increase the number of operating once-through boilers 121 quickly.

  (S104, S105) If any of the above (S101 to S103) is (YES), then whether or not the opening degree of the bypass damper 115 of the exhaust gas boiler apparatus 110 is larger than a predetermined set value A (%). , And whether the header pressure P2 is higher than the predetermined set value B (Pa). If any of them is (NO), the process proceeds to (S107) and instructs the cross flow boiler unit control unit 122 to control the unit number. The number control of the once-through boiler 121 is performed.

  (S106) On the other hand, if the opening degree of the bypass damper 115 is larger than the set value A (%) and the header pressure P2 is higher than the set value B (Pa), the operating number of the once-through boilers 121 is not increased. However, when the opening degree of the bypass damper 115 is reduced, the pressure P1 in the vicinity of the outlet of the exhaust gas boiler 112 is expected to increase and the header pressure P2 of the header 130 is also expected to increase. After the number control suppression instruction is made to the once-through boiler number control unit 122, the process returns to (S101) and the same processing is repeated.

  Specifically, for example, if the setting for performing the operation suppression control of the once-through boiler 121 is made after time t5 shown in FIG. 5, the opening degree of the bypass damper 115 becomes equal to or less than the set value A (%) at time t6. In such a case, the operation control of the once-through boiler 121 is performed by the once-through boiler number controller 122 according to the header pressure P2. That is, for example, when the header pressure P2 becomes equal to or lower than the predetermined reference value C (Pa) at time t7, the number of once-through boilers 121 corresponding to the pressure drop is operated as in time t1. Even when the opening degree of the bypass damper 115 becomes larger than the set value A (%) at time t8, if the header pressure P2 is equal to or less than the set value B (Pa), the bypass damper 115 is more closed than just closed. In order to increase the header pressure P2 promptly, the process proceeds to (S107) and the number control by the once-through boiler number control unit 122 is performed. However, when the header pressure P2 becomes larger than the set value B (Pa) at time t9, the step-up of the once-through boiler 121 is not performed even when the value is equal to or less than the reference value C (Pa). Similarly, if the opening degree of the bypass damper 115 is larger than the set value A (%) at the time t10 to t11, the number of the once-through boilers 121 even if the header pressure P2 becomes the reference value C (Pa) or less. Control is suppressed.

   When the bypass damper opening is greater than or equal to a predetermined value, such as after the time t9 or at time 10 to t11, and particularly when the header pressure P2 is greater than or equal to the predetermined value, the step-up control of the once-through boiler 121 is suppressed. This makes it difficult for the step-up control and the control of the opening of the bypass damper to interfere with each other, so that inadvertent operation (start / stop) of the once-through boiler 121 can be suppressed and energy saving can be facilitated.

  When the above-described control is performed, the operation start and stop of the once-through boiler 121 is not limited to being performed immediately when those conditions are satisfied, but a so-called ON delay or OFF delay is provided to provide hunting. Alternatively, the once-through boiler 121 may be able to recharge temporarily after the suppression of the exhaust gas or the opening degree of the exhaust gas bypass damper becomes equal to or less than the set value.

  Moreover, although the example in which the operation suppression of the once-through boiler 121 is performed according to the opening degree of the bypass damper 115 has been described in the above example, the present invention is not limited thereto, and the steam valve 116 is used instead of or in conjunction with the bypass damper 115. In the case where it is provided, operation suppression may be performed in accordance with the opening degree of the evaporating valve 116 instead of or in addition to the opening degree of the bypass damper 115.

  In the above example, the GE / GT 111 and the exhaust gas boiler 112 are used. However, the present invention is not limited to this. For example, other unused energy such as waste energy or a boiler derived from natural energy is used. These may be used in combination. In other words, for example, when the amount of heat supplied to the boiler or the amount of discharged steam is restricted, it is possible to easily avoid frequent on / off of the once-through boiler by removing the restriction.

110 Exhaust gas boiler device 111 GE / GT
112 Exhaust Gas Boiler 113 Exhaust Gas Boiler Pressure Gauge 114 Valve Opening Control Unit 115 Bypass Damper 116 Steaming Valve 120 Through-flow Boiler Device 121 Through-flow Boiler 122 Through-flow Boiler Number Control Unit 130 Header 131 Header Pressure Gauge 140 Through-flow Boiler Operation Suppression Unit

Claims (8)

A boiler system control device having a first boiler, a second boiler which is a once-through boiler, and a header into which steam generated by the first boiler and the second boiler is introduced,
A second boiler operation that suppresses the operation of the second boiler according to at least one of the degree of restriction of the amount of heat introduced into the first boiler and the opening of the evaporating valve that discharges the steam of the header. A boiler system control device comprising a suppression unit. The boiler system control device according to claim 1,
The boiler system further includes a second boiler number control unit that controls the number of operating second boilers according to the pressure of the header.
The upper air second boiler operation suppression unit is configured to control the second boiler number control unit. A boiler system control device according to any one of claims 1 and 2,
The second boiler operation suppression unit suppresses the operation of the second boiler when at least one of the degree of restriction of the heat amount and the opening degree of the evaporating valve is equal to or greater than a predetermined value. Control device. The boiler system control device according to any one of claims 2 to 3,
The second boiler operation suppression unit further suppresses the operation of the second boiler when the header pressure is equal to or higher than a predetermined value. The boiler system control device according to any one of claims 1 to 4,
The second boiler operation suppression unit can be set so as not to suppress the operation of the second boiler regardless of at least one of the degree of restriction of the heat amount and the opening degree of the evaporating valve. Boiler system control device. The boiler system control device according to any one of claims 1 to 5,
When the second boiler operation suppression unit includes at least one of information indicating that a device for introducing heat into the first boiler is not operating and information indicating a failure of the device, the heat amount A boiler system control device characterized in that it can be set so as not to suppress the operation of the second boiler regardless of at least one of the degree of restriction and the opening of the evaporative valve. The boiler system control device according to any one of claims 1 to 6,
The first boiler includes at least one of an exhaust gas boiler, a waste energy utilization boiler, and a natural energy utilization boiler.
A control device for a boiler system according to claim 1;
The second boiler operation suppression unit;
The first boiler;
The second boiler,
The header above,
A boiler system characterized by comprising

Images