JP2008224127A - Method for controlling number of boiler group - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boiler group and a method for controlling the number of the boiler group with high economic efficiency including an equipment cost, an operation cost, and the like with respect to a specific load state. <P>SOLUTION: The method for controlling the number of the boiler group comprising a latent heat recovery type boiler and an ordinary type boiler is carried out by supplying a predetermined amount of steam by the latent heat recovery type boiler and supplying an amount of steam exceeding the predetermined amount, by the ordinary type boiler, wherein the predetermined amount of steam may be a minimum usage amount or an average usage amount obtained from a steam use curve indicating the operation time - the amount of steam used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for controlling the number of boiler groups composed of a plurality of boilers having different characteristics.

  Hot water or steam supplied by a boiler is used in various ways, and the use state is various. For this reason, fluctuations in the operating rate of the boiler are large and energy efficiency may be a problem. In such a case, a boiler number control method has been proposed in which a boiler group composed of a plurality of boilers is configured and optimal operation thereof is performed to improve energy efficiency.

  Such a number control method for boilers is often a number control method for a group of boilers composed of boilers of the same specification. For example, Patent Document 1 discloses a boiler control method in a multi-can installation system in which steam is generated by a plurality of boilers, which detects a steam flow rate when the steam pressure is stable, and uses this as a reference steam flow value. A boiler control method has been proposed in which when the steam flow rate increases or decreases with respect to the reference steam flow rate value, the combustion state of each boiler is controlled according to the increased or decreased steam flow rate.

  Further, in Patent Document 2, a mode switching device capable of switching between a simultaneous proportional control mode and a maximum combustion fixed control mode is provided in a method for controlling the number of a plurality of boilers provided with a control mechanism for continuously increasing or decreasing the combustion amount. When the load fluctuation is large, the control mode is changed to the simultaneous proportional control mode by the mode switch, and the combustion amount of all the boilers in combustion is increased or decreased simultaneously by the signal from the unit control device. The mode changer sets the control mode to the maximum combustion fixed control mode, fixes the boiler with the highest startup priority to the maximum combustion, and minimizes the number of boilers that increase or decrease the combustion amount with the signal from the unit control device. A number control method has been proposed.

  On the other hand, a method for controlling the number of boilers constituting a group of boilers having different specifications has also been proposed. For example, Patent Document 3 discloses a boiler unit control method for controlling the number of combustion of a plurality of boilers that generate supply steam to a steam-using facility based on the pressure of the supply steam. A plurality of different boilers different from each other in at least one of the characteristic information including the evaporation ratio, and the plurality of boilers based on the pressure of the supply steam in the control pressure zone, the difference in the characteristic information, and the start or stop sequence A method for controlling the number of boilers that increases or decreases the number of burners is proposed.

  Patent Document 4 discloses a boiler number control method for controlling the number of combustion of a plurality of boilers that generate steam supplied to steam-using equipment, and is a small evaporation having a combustion state with a smaller evaporation amount than other boilers. A boiler with higher load followability than that of other boilers and / or other boilers is included, and the small evaporation boiler and / or boiler with higher load followability are preferentially burned according to the steam load and / or its fluctuation state. A method for controlling the number of boilers whose volume is to be increased or decreased has been proposed.

JP 2006-234359 A Japanese Patent Laid-Open No. 2002-130602 JP 2005-16829 A JP 2005-55014 A

  However, it is not always clear how to control the amount of steam used (load) in such a conventional boiler unit control method, and in what priority order the boilers are operated. It is not clear what to do. Moreover, in the efficient operation of the boiler group, it is necessary to consider not only energy efficiency, which has been a problem in the past, but also comprehensive economics including equipment costs and operating costs.

  An object of the present invention is to propose a method for controlling the number of boiler groups with high economic efficiency, including equipment costs and operating costs with respect to the load state, in consideration of such conventional problems and requirements.

  The number control method of the boiler group according to the present invention is a number control method of a boiler group consisting of a latent heat recovery type boiler and a normal type boiler, wherein a predetermined steam amount is supplied by the latent heat recovery type boiler, and the predetermined steam amount It is carried out by supplying an amount of steam exceeding the normal boiler.

  In the invention of the method for controlling the number of boiler groups, the predetermined steam amount is preferably set to a minimum use amount or an average use amount obtained from a steam use curve representing an operation time-steam use amount.

  According to the method for controlling the number of boiler groups according to the present invention, it is possible to perform an operation with high energy efficiency with respect to a load state, and it is possible to perform an operation with high economic efficiency including equipment expenses and operation expenses. it can.

  Hereinafter, an embodiment of the invention of a method for controlling the number of boiler groups according to the present invention will be described. The number control method of the boiler group according to the present invention is a number control method of a boiler group consisting of a latent heat recovery type boiler and a normal type boiler, and supplies a predetermined steam amount by the latent heat recovery type boiler, and the predetermined steam amount This is a method for controlling the number of boiler groups by supplying an amount of steam exceeding the above with a normal boiler.

  A latent heat recovery type boiler refers to a latent heat recovery type boiler including a boiler with an economizer. Such a latent heat recovery type boiler is generally several percent higher in thermal efficiency than a normal type boiler without a latent heat recovery device. On the other hand, in the latent heat recovery type boiler, the entire equipment becomes large, and the price, installation area, and installation cost of the apparatus itself are more expensive than the normal type boiler. Further, such a latent heat recovery type boiler has a feature that frequent start / stop is not preferable because the thermal inertia load at the start / stop is large.

  On the other hand, a normal boiler refers to a boiler without a latent heat recovery device, and is more compact and less expensive than a latent heat recovery boiler. In both the latent heat recovery type boiler and the normal type boiler, any of a proportional control method, a three-value control method, and the like can be used.

  The method for controlling the number of boiler groups according to the present invention comprises a boiler group from a latent heat recovery type boiler and a normal type boiler having such characteristics, and has high thermal efficiency and is economical including equipment costs and operating costs. It is a method of performing high operation. That is, first, in principle, the latent heat recovery type boiler is always in an operating state to maximize its operating rate. And it is the method of operating a normal type | mold boiler, when only the latent heat recovery type | mold boiler has too much usage-amount of steam and cannot respond to load. In the configuration of this boiler group, the configuration ratio of the latent heat recovery type boiler is preferably 50% or less.

For example, when the load state is a steam use curve A in the graph representing the operation time-steam usage in FIG. 1, the following operation is performed on the boiler group. First, the minimum steam consumption V ₁ or less is to be covered by operating the latent heat recovery boiler. When the excess of steam usage V ₁ was, it operates the latent heat recovery boiler and a normal boiler, performs the operation for supplying steam corresponding to the load by performing the originating stop normal boiler as required. On the other hand, the latent heat recovery type boiler is operated for a steam amount equal to or less than the average steam consumption V ₂ . Then, when exceeding the average steam usage V _2, operate the latent heat recovery boiler and a normal boiler, to perform the operation for supplying steam corresponding to the load by performing the originating stop normal boiler as required It can also be. Note that there can be a plurality of latent heat recovery boilers or normal boilers.

In addition, the following operations can be performed. That is, first, the steam amount equal to or less than the minimum steam consumption V ₁ is provided by operating the latent heat recovery boiler. When the average steam consumption is V ₂ or less, the latent heat recovery boiler and the first normal boiler are operated so as to be able to cope with the load. Further, when the average steam consumption V ₂ is exceeded, the latent heat recovery type boiler and the first and second normal type boilers are operated so as to cope with the load. That is, in the case of this example, a boiler group consisting of three groups of a latent heat recovery boiler group, a first normal boiler group, and a second normal boiler is configured. This is a method of controlling the number of units.

  As an example of the boiler group, a configuration of a boiler group including one latent heat recovery type boiler and two normal type boilers of the same specification is schematically shown in FIG. As shown in FIG. 2, the boiler group 100 includes a latent heat recovery type boiler 10 </ b> A and normal type boilers 10 </ b> B and 10 </ b> C having the same specifications. The load 50 is supplied. The control of each boiler is controlled by the control device 30 based on the output of the sensor 35 that detects the steam pressure or the amount of use provided in the steam header 15.

It is a graph which shows the steam usage condition of load. It is a schematic diagram which shows the structure of a boiler group.

Explanation of symbols

10 (10A, 10B, 10C) Boiler
15 Steam header
30 Control unit
35 sensors
50 load
100 boilers

Claims (2)

  A method for controlling the number of boiler groups comprising a latent heat recovery type boiler and a normal type boiler, wherein a predetermined steam amount is supplied by a latent heat recovery type boiler, and a steam amount exceeding the predetermined steam amount is supplied by a normal type boiler. A method for controlling the number of boiler groups.   2. The method for controlling the number of boiler groups according to claim 1, wherein the predetermined steam amount is a minimum usage amount or an average usage amount obtained from a steam usage curve representing an operation time-steam usage amount.

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