JP2006214723A - Controller of heat source system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a heat source system of high tracking property to load fluctuation. <P>SOLUTION: The controller of the number of heat source systems has a plurality of heat source apparatuses B1, B2, B3 and B4 transferring to combustion after each of them scavenges the inside of a furnace, and a number setting means 4 for manually varying the number of heat source apparatuses to be put into a scavenge state in a combustion apparatus for combusting a required number of heat source apparatuses B1, B2, B3 and B4 according to a load amount. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a heat source system having a plurality of boilers and other heat source devices that shift to combustion after scavenging in a furnace, and that burns and stops a required number of heat source devices according to the load amount. .

  For example, in a boiler system having a plurality of boiler units, activation is performed sequentially in accordance with a predetermined activation sequence. In such a system, since scavenging (purging) is generally required for each startup of each boiler unit, there is a problem that the system does not follow the load variation. As a solution to this problem, in Japanese Patent Laid-Open No. 63-238303, a combustion start signal is supplied to a certain boiler according to the startup sequence, and at the same time, a pre-purge standby signal is sent to a boiler that is to be shifted to combustion next. A method for supplying the water has been proposed.

  However, in this proposal, the number of boilers that are on standby for pre-purge is basically limited to one, so that in systems where sudden load fluctuations are expected, the followability to load fluctuations is not sufficient. There was a problem. Further, in this proposal, when a combustion start signal is given to a certain boiler, a pre-purge standby signal is always supplied to the boiler to be shifted to the next combustion state and pre-purge is started, that is, one boiler is always Since waiting for the pre-purge, unnecessary purge is performed, which causes a problem of thermal loss.

  The present invention has been made to solve the above-described problem, and has a plurality of heat source devices each of which moves to combustion after scavenging in the furnace, and the required number of units according to the load amount. An apparatus for burning a heat source device is characterized by comprising a number setting means for manually changing the number of heat source devices in a scavenged state.

According to the present invention, the number of heat source devices to be in the scavenging state can be manually set. Therefore, when the load fluctuation of the system is large, the number of heat source devices to be in the scavenging state is increased, so that the load fluctuation can be increased. Many heat source devices can be promptly shifted to a combustion state, and a control device for a heat source system with good followability to load fluctuations can be provided. In addition, when the load fluctuation of the system is not large, the effect of reducing the heat loss due to scavenging is great by reducing the number of heat source devices in the scavenging state.

(Embodiment)
As an embodiment of the present invention, there are a plurality of heat source devices that each move to combustion after scavenging in the furnace, and the scavenging device is configured to burn the required number of heat source devices according to the load amount. It is assumed that a number setting means for manually changing the number of heat source devices to be in a state is provided.

  This embodiment will be described in detail below. Heat source equipment includes steam boilers, hot water boilers, etc. that supply heat to loads that require heat in the form of steam, hot water, etc. The heat source equipment is a scavenging (also called purge, ventilation) of the furnace, that is, the combustion furnace. Transition to combustion. This scavenging is usually a scavenging that is at least four times the furnace volume for safety and is a continuous scavenging, but is not limited to this if allowed for safety, and may be intermittent scavenging. .

The heat source device can take a stopped state, a scavenging state, and a combustion state, and preferably, the combustion state can take a multi-stage combustion state such as low combustion, medium combustion, and high combustion. . In addition, the present invention is applied to a system having two or more heat source devices. When the heat source equipment is a steam boiler, the load amount can be detected by detecting the steam pressure or steam temperature of the common steam header to which the output side steam pipe of each boiler unit is connected. It can be detected by detecting the amount of air supply (supplied steam) with a flow sensor or by detecting the operating status of the steam load equipment.

  In addition, when the heat source equipment is a hot water boiler, the load amount is ascertained by the difference between the tapping temperature supplied to the load and the set temperature, the difference between the temperature of hot water returning from the load and the set temperature, the flow rate, etc. It is determined appropriately according to the type of heat source device. Desirably, according to this load amount, each heat source device starts combustion sequentially according to a predetermined order by a unit control means (system control means) for controlling the combustion state and the number of units, and stops according to a predetermined order. Be controlled. The order of stopping the heat source devices is desirably the reverse of the order of starting combustion, but is not limited thereto.

  Further, the control for setting the heat source device to the scavenging state is performed by the number control means, and the combustion start signal is not yet supplied by the number control means at the current load amount, and the combustion start signal is output when the load increases. A scavenging operation is instructed to the heat source device so that the heat source device in the order of supply is continuously scavenged. In this scavenging, after a predetermined amount of scavenging has been completed, it is desirable to reduce the amount of blown air compared to the normal scavenging.

  The number setting means for setting the number of heat source devices to be in the scavenging state is to set the number of heat source devices to be in the scavenging state to one or a plurality of two or more. Accordingly, when the combustion start signal is not yet supplied and the load increases, the scavenging signal is supplied only to the heat source device to which the combustion start signal is supplied next. In the case of two units, the combustion start signal is not yet supplied according to the state of the load, and when the load increases, the heat source device to which the combustion start signal is supplied next, and then the combustion start signal The scavenging signal is supplied only to the heat source device to which the gas is supplied. Here, the number of scavenging is set by the number setting means, but when the number of heat source devices not in the combustion state is less than the set number (for example, two) (for example, one or zero), only the heat source device capable of scavenging operation is used. Is the target of the scavenging instruction.

  The number setting method is a manual setting method in which the number is set manually. This manual setting method is configured such that the system controller is provided with a number setting means, and the system supplier or user can vary the set number by judging the state of the load for installing the system.

  Hereinafter, examples corresponding to the embodiment in which the heat source device is a steam boiler and the number setting means is a manual number setting method will be described with reference to the drawings. In the figure, B1, B2, B3, and B4 are first to fourth boilers installed in a plurality of units, and are in an operation stop state (a state in which neither combustion nor scavenging is performed), a low combustion state, and a high combustion state. This so-called three-position control is possible, and scavenging (also referred to as purging) in a furnace (not shown) is performed before shifting to low combustion and after stopping combustion. The priority of combustion start of each boiler is in the order of B1, B2, B3, B4, and the order of stop is the opposite.

  The steam output pipes A1, A2, A3, and A4 of each boiler are connected to a common steam header (steam collecting section) 1. The steam header 1 is provided with a pressure detector 2 that detects the internal steam pressure and detects the load state. The load amount is detected on the basis of the detected pressure signal of the pressure detector 2, and the start sequence (which may be determined in advance or in accordance with the control procedure as shown in FIG. In accordance with a predetermined combustion control pattern, the required number of boilers are combusted and stopped, a predetermined number of scavenging operations are performed, and control is performed so as to follow the load fluctuation.

The number controller 3 includes a microcomputer (not shown) and software for controlling the operation thereof, and FIG. 6 shows an outline of a part of the software. Specifically, the control by the number controller 3 is based on the combustion control pattern shown in FIGS. 4 and 5, that is, the control by the stop number control pattern and the control by the start number control pattern shown in FIGS. 2 and 3. Each boiler can be controlled to stop, continuous scavenging (continuous P) (hereinafter simply referred to as scavenging), low combustion, and high combustion according to the detected pressure band (P1 to P2), and the number of set numbers can be manually input Control is performed so that the number of units set by the setting means 4 is scavenged. Here, in the pressure range where the set number of scavenging units cannot be secured, the number of boilers less than the set number are scavenged. Further, in the control of FIG. 3, when a sudden load increase fluctuation occurs and it becomes necessary to shift a certain boiler from scavenging to high combustion, in order to obtain a substantially high combustion state, 2 in the scavenging state transiently. One boiler is shifted to low combustion, then one is shifted to high combustion, and the other is shifted to scavenging. The control for quickly generating this substantially high combustion state is similarly applied even when the number of scavenging is three or more.

  The number control (operation control) by the number controller 3 of this embodiment will be described in detail below with reference to FIGS. Now, suppose that the user sets the set number to one by the number setting means 4 and starts the system (starts operation), assuming that the load fluctuation is not so much. In FIG. 6, it is determined in step S1 that the system is activated. In this case, the process proceeds to step S2 due to YES. In step S2, the combustion control pattern is selected according to the number of scavenging units set by the unit setting means 4. Subsequently, the process proceeds to step S3, where it is determined whether or not the required number of combustion NQ (determined from FIG. 2) with respect to the steam pressure is equal to the number of currently burned NG. If YES, the process stops at step S3. In this case, the process proceeds to step S4 with NO, and it is determined whether the required number of combustion NQ is larger than the current number of combustion NG. In this case, NO is determined and the process proceeds to step S6. In step S6, according to the control pattern selected in step S2, that is, the activation pattern of FIG. 2, one scavenging (continuous P) is instructed to each of the boilers B1 to B4, and the boilers are sequentially one by one. After starting, the process proceeds to step S7, where it is determined whether or not there is an operation stop request for the entire system, and the process returns to step S3. Thus, S3 → S4 → S6 → S7 → S3 in each step is repeated until YES is determined in step S4.

  As shown in FIG. 2, the boiler B1 is first scavenged (state C1), then the boiler B1 is low burned, the boiler B2 is scavenged (state C2), the boiler B1 is then high burned, and the boiler B2 is scavenged. As in (State C3), start-up control is performed to sequentially control the boilers B1 to B4 to scavenging, low combustion, and high combustion. If YES is determined in step S4 in this way, one scavenging is instructed and one of the boilers B1 to B4 is sequentially stopped according to the stop pattern of FIG.

  Next, a case where the user determines that the load fluctuation is large and sets the set number to two by the number setting unit 4 will be described below. In FIG. 6, it is determined in step S1 that the system has been activated. In this case, the process proceeds to step S2 due to YES, and a combustion control pattern corresponding to two set units is selected. In step S3, it is determined whether the required number of combustion NQ (determined from FIG. 3) with respect to the steam pressure is equal to the number of currently burned NG. If the determination is YES, the process stops at step S2. In this case, the process proceeds to step S4 with NO, and it is determined whether the required number of combustion NQ is larger than the current number of combustion NG. In this case, NO is determined and the process proceeds to step S6. In step S6, in accordance with the activation pattern of FIG. 3, two scavenging units are instructed to each of the boilers B1 to B4, the boilers are sequentially activated one by one, the process proceeds to step S7, and the operation of the entire system is stopped. It is determined whether there is a request, and the process returns to step S3. Thus, S3 → S4 → S6 → S7 → S3 in each step is repeated until YES is determined in step S4.

As shown in FIG. 3, the boilers B1 and B2 are first scavenged (state E1), and then the boiler B1
Are set to low combustion, boilers B2 and B3 are scavenged (state E2), boiler B1 is then highly combusted, and boilers B2 and B3 are scavenged (state E3). Start-up control is performed to control low combustion and high combustion. If YES is determined in step S4 in this manner, two scavenging units are instructed according to the stop pattern of FIG. 5, and each of the boilers B1 to B4 is stopped one by one.

  As described above, according to the control in FIG. 3 in which the number of scavenging is two, the followability to the load fluctuation is better than in the case of the control in FIG. That is, for example, if the load suddenly increases in the state E3 and the operation state of the state E5 becomes necessary, as shown in FIG. 7, the scavenged boilers B1 and B2 are set to low combustion transiently, and then the boiler B2 is made high. It is set as combustion, boiler B3 is returned to scavenging, and boiler B4 is scavenging. Therefore, a predetermined pre-purge time is not required to shift the boiler B2 to the high combustion, and it can be made the same as the state in which the boiler B2 is immediately shifted to the high combustion in the transient state. Good sex. On the other hand, in the conventional example in which scavenging is not provided, the boiler B2 shifts from pre-purge → low combustion → high combustion, so that pre-purge time is required and the boiler B2 is in a low combustion state in a transient state (immediately). Therefore, the followability to load fluctuation is poor. Further, in the control of FIG. 2, the boiler B2 shifts from low combustion to high combustion, and therefore, the boiler B2 has a low combustion state in a transient state, so that the followability to the load fluctuation is inferior compared with the control of FIG. .

It is a figure which shows schematic structure of one Example of this invention. The number control pattern of starting when the number of scavenging of one Example of this invention is set to 1 is shown. The number control pattern of starting when the scavenging number of one Example of this invention is set to 2 is shown. The number control pattern of a stop when the scavenging number of one Example of this invention is set to 1 is shown. The number control pattern of a stop when the scavenging number of one Example of this invention is set to 2 is shown. It is a flowchart figure which shows the control procedure of one Example of this invention. It is operation | movement explanatory drawing of one Example of this invention.

Explanation of symbols

B1, B2, B3, B4 boiler (heat source equipment)
4 Number setting means

Claims (1)

Each unit has multiple heat source devices that shift to combustion after scavenging in the furnace, and burns the required number of heat source devices according to the amount of load. A heat source system control device comprising a number setting means that can be varied according to the above.

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