JPH0336403A - Automatic control of number of boilers including blow instruction operation - Google Patents

Abstract

PURPOSE:To supply stably a required amount of steam without hindrance in copying with load by issuing in due order a blow instruction signal only to a number of boilers which have no effect on a required amount of steam supply even if many boilers reach the time of blow simultaneously. CONSTITUTION:An electrically powered valve 8 for whole blow which is connected to the bottom section of a boiler controls the discharge of boiler water. In order to detect the time of whole blow an electric conductivity sensor 9 is provided in the boiler at its lower section and it judges whether or not the boiler water is too much thickened, or the combustion times are summed up and the sum is compared with the set value to judge the time of whole blow. A soot blow pipe 10 which has many injection holes is installed to face against the heat transfer face of the boiler, and it is connected by an electrically powered valve 11 for soot blowing which controls the supply of a cleaning medium for high pressure water, steam, etc. In order to detect the time of soot blowing the temperature of the exhaust gas is measured by a temperature sensor 13 that is provided in the flue in order to judge the degree of soot attachment. In carrying out the blow operation blow instruction signal is issued to one or a limited number of boilers in due order so that a required amount of steam supply is not affected.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for automatically controlling the number of boilers in a multi-boiler installation system. It includes.

[Conventional technology]

Generally, when a boiler is operated for a long time, the canned water becomes concentrated and carryover occurs, and deposits such as sludge accumulate at the bottom of the can, so it is recommended to periodically perform a full blow operation to drain all the canned water. I have to. Additionally, as the boiler operates, soot adheres to and accumulates on the heat transfer surface, obstructing heat transfer and reducing boiler efficiency. It is also necessary to perform the operations appropriately.

[Problem to be solved by the invention]

However, these blowing operations are usually performed manually by a boiler operation manager, which is cumbersome and time-consuming, making boiler maintenance management complicated. In particular, in a multi-can installation system where multiple boilers are installed, the amount of work increases, placing a considerable burden on the boiler operation manager.

Therefore, it is desirable to automate these blowing operations, but since it is necessary to stop boiler operation when performing blowing operations, in a multi-can installation system, multiple boilers reach the blowing time at the same time and cannot be used for blowing operations. If this is done, the amount of steam will suddenly decrease or stop completely, making it impossible to provide a stable supply of steam.

[Means to solve the problem]

In view of the above-mentioned problems, this invention enables appropriate blowing operations to be performed when automating blowing operations in a multi-boiler installation system. In an automatic number control method that starts and stops combustion according to the load, when any boiler reaches its blowing time, a blow instruction signal is sent to prevent more than a preset number of boilers, including that boiler, from blowing at the same time. It is characterized by suppression.

[Function] According to the present invention, even if a large number of boilers reach their blowing time at the same time, a blow instruction signal can be issued to only one of them or only to a number of boilers that does not affect the amount of steam supplied. , there is no problem in handling the load. Further, by selecting a time period when the amount of steam used is small and issuing the blow instruction signal, it is possible to stably supply steam to the required amount of steam.

〔Example〕

Preferred embodiments of the present invention will be described below with reference to the drawings.

In the figure, (1) is a boiler, each of which is equipped with a combustion device (2) and a blow controller (3), and is connected to a common steam header (5) through a steam pipe (4). This steam header is equipped with a pressure sensor (6) to detect the internal steam pressure, and based on the pressure detection signal, the number controller (7) controls combustion and shutdown of each boiler. It has become. In addition, blow controller (3)
may be incorporated into the number controller (7).

Figure 2 shows the details around the boiler (1). (8) is an electric valve for full blowing connected to the bottom of the boiler, which controls the discharge of canned water. To detect the full blow period, install an electrical conductivity sensor (9) at the bottom of the can to determine whether the can water is overconcentrated, or integrate the combustion time and compare it with a set value. There are methods for determining when it is time for a complete blowout.

00 is a soot blow pipe with a large number of ejection holes, and is placed opposite the heat transfer surface in the boiler, and is equipped with a soot blow electric valve (1) that controls the supply of cleaning media such as high-pressure water and steam.
Connect 0. To detect the soot blow time,
For example, the exhaust gas temperature is measured by a temperature sensor 03) installed in the flue q, and the degree of soot adhesion is determined based on the degree of rise.

FIG. 3 shows an example of automatic number control, where boilers are No. 1, 1. No, 2. It is set to operate preferentially in the order of No. and No. 3. The control pressure is divided into seven steam pressure zones (a-g), and in the lower limit steam pressure zone a, all boilers are in a state of high combustion H, and when the steam pressure in the ladder rises to the steam pressure zone, boiler No. 3 shifts to low combustion, and then stops when the steam pressure rises to the edge of the steam pressure zone, and as the steam pressure increases, the combustion state of all cans changes to HHH-+HHL.
-4HH-+HL→H→L, and at the upper steam pressure zone g, all the vessels are stopped. Also, when the steam pressure decreases, the boiler is No. 1. No, 2. No, 3
The combustion state changes as follows: LH→HL-HH-HHL→HHH. Priorities are rotated as appropriate so that the operating time of the boilers is averaged, and if an abnormal boiler occurs, the next ranked boiler is operated for backup control.

In the above configuration, when each boiler issues a signal indicating that the blowing time has been reached, control is performed as follows. When performing blowing work, it is necessary to stop the boiler, so in order to avoid affecting the amount of steam supplied to the load even if many boilers reach their blowing time at the same time, one boiler or a limited number of boilers may be used. A blow instruction signal is issued only in sequence.

When issuing a blow instruction signal to a boiler that is currently burning, the boiler that is assigned to the blowing operation of that boiler is activated as a backup, or when a boiler with a higher priority reaches its blowing time, after rotation, a boiler with a lower priority is activated. A blow instruction signal is issued when this happens.

In addition, regarding the time period when the blow instruction signal is issued, past boiler operation results are memorized by day of the week and hourly, and the blow instruction signal is issued only during times when the steam usage is low and there is sufficient load. , and select and specify the blow-allowed time period and blow-prohibited time period in advance.

〔Effect of the invention〕

This invention has the above configuration, and even if a large number of boilers reach their blowing time at the same time, a blow instruction signal is sequentially issued to only the number of boilers that does not affect the required amount of steam supply, and Since the blow instruction signal is issued during a time period when the required amount of steam supply is not affected, there is no problem in responding to the load, and it is possible to stably supply steam with respect to the required amount of steam. Therefore, the blowing work can be smoothly automated and the burden on the boiler operation manager can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is an enlarged system diagram of its main parts, and Fig. 3 is a graph showing an example of a change in boiler combustion pattern due to a change in steam pressure in automatic number control. It is. (1)...Boiler (2)...Combustion device (3)...Blow controller (4)...Steam pipe (
5)...Steam header (6)...Pressure sensor (7)...Number of units controller (8)...Electric conductivity sensor (+01...) Soot blow pipe 00...Electric valve for soot blow

Claims (2)

[Claims] (1) Combustion of multiple boilers (1) according to the load amount,
In the method for automatically controlling the number of boilers to be stopped, when any boiler reaches the blowing time, a blowing instruction signal is suppressed so that a preset number or more of boilers including that boiler do not blow at the same time. A method for automatically controlling the number of boilers including instruction operation. (2) Combustion of multiple boilers (1) according to the load amount,
A method for automatically controlling the number of boilers to be stopped, including a blow instruction operation, characterized in that when the boiler reaches its blowing time, a blow instruction signal is issued only during a predetermined time period.