JP5842492B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system that controls combustion of a plurality of steam boilers by a number controller.

  Steam boilers concentrate in long-term operation. As described in Patent Document 1, etc., can water is blown according to the accumulated combustion time so that the concentration does not proceed excessively.

  The inventor of this application has found that there is the following problem when the blow according to the accumulated combustion time is applied to a boiler system that controls the combustion of a plurality of steam boilers by a number controller.

  That is, each steam boiler burns by a combustion instruction signal from the number controller based on the pressure in the steam header (first pressure), but the pressure (second pressure) in the can body of each steam boiler is the first pressure. If it is lower than that, since there is no outflow of steam from each steam boiler to the steam header, that is, although the can water is not concentrated, combustion is performed, so that it is counted as an integrated combustion time of blow control. For this reason, blow is performed more than necessary, resulting in an increase in thermal loss and insufficient concentration of the can water.

No. 7-49208

  The problem to be solved by the present invention is to prevent blowing more than necessary, reduce thermal loss, and prevent insufficient concentration of canned water.

This invention was made in order to solve the above-mentioned subject, and the invention according to claim 1 includes a plurality of steam boilers, and a steam collecting portion where steam of each steam boiler gathers from each steam boiler. A boiler controller that is provided in each steam boiler and controls the blow of canned water according to its accumulated combustion time; and a number controller that controls combustion by transmitting a combustion instruction signal to each of the boiler controllers. The number controller is configured to control combustion by transmitting a combustion instruction signal to each boiler controller according to a first pressure of the steam collecting portion, and each boiler controller is in combustion a is, when the outflow of steam into the steam collecting unit determines that the not a comparison between the second pressure and the first pressure of the can body of the steam boiler, counted as the integrated burn time for the blow control It is characterized by not .

According to the first aspect of the present invention, even when the steam boilers are in combustion, while the steam does not flow out from the steam boilers, the accumulated combustion time is not counted. Is done. In addition, since it is possible to determine that there is no outflow of steam by each of the boiler controllers by detecting the first pressure and the second pressure, the system configuration is compared with that detected by the flow sensor. There is an effect that can be simplified.

Before Symbol determines the outflow of steam due to absence each boiler controller, the second pressure of the can body of the steam boiler is made between lower than the first pressure.

  According to this invention, blow more than necessary can be prevented, thermal loss can be reduced, and insufficient concentration of canned water can be prevented.

It is a schematic block diagram of embodiment of the boiler system which implemented this invention. It is a flowchart figure explaining the control program of the embodiment.

(Configuration of the embodiment)
Hereinafter, a boiler system 1 according to an embodiment of the present invention will be described in detail with reference to the drawings. The boiler system 1 includes a plurality of (three in this embodiment) steam boilers (hereinafter simply referred to as boilers) 2A, 2B, and 2C that are capable of controlling the amount of evaporation at stepwise combustion positions. A common steam header 3 for connecting the boilers 2A, 2B, 2C with steam pipes (not shown), a pressure detector 4 for detecting the steam pressure inside the steam header 3, and detection by the first pressure detector 4 In accordance with the pressure (first pressure) P1, a required number of boilers are combusted and stopped in accordance with a preset startup sequence based on a previously stored number control program, and control is performed so as to follow a change in steam load. A number controller 5 is provided. The steam header 3 is a steam collecting part where steam from the boilers 2A, 2B, 2C of the present invention is collected, and is connected to the steam using device 6 by a steam pipe (reference numeral omitted).

  Each boiler 2A, 2B, 2C has a can 7A, 7B, 7C that generates steam by combustion of a burner (not shown), and a second pressure that detects the pressure in each can 7A, 7B, 7C. Second pressure detectors 8A, 8B, 8C, 8A, 8B, 8C, drainage channels (blow lines) 10A, 10B, 10C having valves 9A, 9B, 9C for blow control, and a control program stored in advance. Boiler controllers 11A, 11B, and 11C that control valves (blow valves) 9A, 9B, and 9C based on signals such as the detected pressure (second pressure) P2 of 8C are provided.

  The control program by each boiler controller 11A, 11B, 11C includes concentration blow control in addition to combustion control and water level control. The enrichment blow control is a well-known control. Based on the combustion instruction signal from the number controller 5, the time when the boilers 2A, 2B, 2C are burned is measured, the combustion time T is integrated, and this integrated combustion time T Based on the above, the concentration of the can water in the can bodies 7A, 7B, 7C is calculated, and when the calculated concentration exceeds a predetermined value, the concentration blow amount is calculated and the concentration blow is executed. In addition, when performing concentration blow, each boiler controller 11A, 11B, 11C opens each valve 9A, 9B, 9C for the time corresponding to the calculated enrichment, and drains 10A, Discharge through 10B and 10C.

  The present invention is characterized in the control for calculating the integrated combustion time T in the concentrated blow control, and calculates the concentrated blow amount based on the integrated combustion time T, that is, the longer the integrated combustion time T, the larger the concentrated blow amount. If so, it does not matter how to calculate the concentration blow amount and control the concentration blow by the concentration blow amount.

The feature of the calculation control of the integrated combustion time T is that combustion is being performed by an instruction signal from the number controller 5, and there is no outflow of steam from each boiler 2A, 2B, 2C to the steam header 3. When it is determined, it is not counted as the cumulative combustion time T for blow control, and when it is determined that there is steam outflow, it is counted as the cumulative combustion time T for blow control.

  And in this embodiment, each boiler controller 11A, 11B, 11C is performing combustion by an instruction | indication signal, Comprising: It is performed by the comparison with the 2nd pressure P2 in the can body of each steam boiler, and the 1st pressure P1. . Specifically, if the state where the second pressure P2 of each boiler 2A, 2B, 2C is lower than the first pressure P1 continues for a set time (for example, 5 seconds), it is determined that “there is no outflow of steam”. When the second pressure P2 is higher than the first pressure P1, it is determined that “there is steam outflow”. An example of calculation control of this integrated combustion time T is shown in FIG.

  The number control program by the number controller 5 is a well-known control, and is a combustion number control corresponding to the load amount. The required number of combustion is determined by the first pressure signal, and each boiler controller 11A, 11B, This is a control for outputting a combustion instruction or combustion stop (including combustion standby) signal to 11C.

  The number control is, for example, control as disclosed in Japanese Patent Publication No. 6-92804, but is not limited thereto. The combustion control system of each boiler 2 is not limited to the three positions of the stop state, the low combustion state (first combustion position) L, and the high combustion state (second combustion position) H. It can be a control method. In addition, a stepless control method such as a three-position control can be used.

(Operation of the embodiment)
Next, the concentration blow operation of this embodiment will be described with reference to FIG. Now, it is assumed that only the boiler 2 </ b> A is combusting based on a preset starting order (starting priority order) based on a combustion instruction signal from the number controller 5. Then, it is assumed that an increase in the steam load is detected by the first pressure detector 4 and a combustion instruction signal is newly issued to the boiler 2B on standby for combustion.

  Referring to FIG. 2, boiler controller 11B of boiler 2B determines YES in step S1 (hereinafter, step SN is simply referred to as SN), and boiler 2B starts combustion. And it transfers to S2 and it is determined whether the 2nd pressure P2 is smaller than the 1st pressure P1. In the case of P2> P1, since the steam is flowing out from the can 7B of the boiler 2B toward the steam header 3, the process proceeds to S3 and is counted as an integrated combustion time T for the concentrated blow control.

  P1> P2 occurs at the time of startup (cold startup) in a state where the boiler 2B has stopped combustion for a while. If P1> P2 continues for a predetermined time, YES is determined in S2, and the process proceeds to S4. In S4, the accumulated combustion time T is not counted even though the boiler 2B is burning. Note that P1> P2 also occurs during pressure holding control, which is one of standby control based on an instruction signal from the number controller 5. The standby control is control for keeping each boiler in a state where the load followability is good, and the pressure holding control is control for the purpose of enhancing the responsiveness as a warm-up state in advance with a pressure that does not contribute to steam supply.

  In this way, in the state of P1> P2, the steam in the can 7B does not flow to the steam header 3 although the boiler 2B is combusting, that is, no concentration of the can water has occurred. The cumulative combustion time T that determines the amount is not counted. As a result, even if P1> P2, the cumulative combustion time T is not increased more than necessary as compared with the case where the cumulative combustion time T is counted. As a result, it is possible to prevent the concentration blow from being performed more than necessary. And since unnecessary discharge of can water is prevented, thermal loss can be reduced and insufficient concentration of can water can be prevented.

  The present invention is not limited to the above-described embodiment, and the determination that “there is no outflow of steam” by each of the boiler controllers 11A, 11B, and 11C is from the number controller 5 in the above-described embodiment. While the combustion is performed by the instruction signal, the second pressure P2 of each boiler 2A, 2B, 2C is lower than the first pressure P1, but this is not a limitation, and each boiler 2A, 2B, 2C can A flow rate sensor (not shown) for detecting the flow of steam is provided in the pipe line (not shown) from the bodies 7A, 7B, 7C to the steam header 3, so that “no steam outflow” is judged by this flow rate sensor. Can be configured.

2A, 2B, 2C Steam boiler (boiler)
3 Steam header (steam collecting part)
4 First pressure detector 5 Number controller 8A, 8B, 8C Second pressure detector

Claims (1)

Multiple steam boilers,
A steam collecting portion where the steam of each steam boiler gathers from each steam boiler;
A boiler controller that is provided in each steam boiler and controls the blow of canned water according to its accumulated combustion time;
A unit controller for controlling combustion by transmitting a combustion instruction signal to each of the boiler controllers,
The number controller is configured to control combustion by transmitting a combustion instruction signal to the boiler controllers according to a first pressure of the steam collecting portion,
Each boiler controller, a combustion, when the outflow of steam into the steam collecting unit determines that the not a comparison between the second pressure and the first pressure of the can body of the steam boiler, blow A boiler system that is not counted as an integrated combustion time for control.

Images