JPS61173004A - Method of controlling coal burning heat-accumulation boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for controlling a coal-fired thermal storage boiler.

[Conventional technology]

In a typical boiler, fuel and water are supplied in proportion to the required amount of evaporation to maintain a constant water level and constant pressure.

Therefore, a typical boiler cannot supply steam exceeding its rated evaporation amount.

Furthermore, coal-fired boilers have the disadvantage that it is difficult to change the amount of combustion compared to oil- or gas-fired boilers, and they are susceptible to load fluctuations.

In addition, the boiler and the steam generator are integrated, and the pressure and water level are raised so that they are not operated as a boiler and are controlled in the same way as the boiler described above, and when a large amount of steam is required, the water supply is turned off. Regenerative boilers are known which are shut down and operated as an accumulator to generate large amounts of steam.

However, conventionally known thermal storage boilers are fired with heavy oil or gas, and therefore the amount of combustion can be highly controlled.

Therefore, thermal storage boilers are suitable for coal-fired combustion rather than oil- or gas-fired combustion because they can be operated with a substantially constant combustion volume or with a gradual fluctuation in a long-period fluctuation cycle. An optimal control method for coal-fired heat storage boilers has not yet been proposed.

[Problem that the invention seeks to solve]

The purpose of the present invention is to solve the above-mentioned drawbacks of the conventional technology and to provide a control method suitable for a high-performance coal-fired heat storage boiler that has the performance of an accumulator that generates much more steam than the rated value. It is something to do.

[Means for solving problems]

Therefore, the gist of the present invention is to maintain combustion substantially constant or to vary it slowly, to vary the amount of water supplied in inverse proportion to the amount of evaporation, and to supply a large amount of water during light loads. This causes the water level to rise along with the pressure to store energy, and when a large amount of steam is required, the amount of water supplied is reduced to release the energy and release a large amount of steam.

[Effect]

By configuring it as described above, it is possible to provide the same capacity as if an accumulator were built in, and it is now possible to supply more than twice the rated evaporation amount, and also to achieve the original maximum efficiency as a boiler. You will be able to demonstrate your abilities.

〔Example〕

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

1 and 2 are a cross-sectional front view and a cross-sectional side view showing one embodiment of a coal-fired heat storage boiler according to the present invention, and FIG.
The cross-sectional side view, piping system and control circuit diagram, and FIG. 4 are graphs showing the relationship between the amount of steam generated and the amount of water supplied.

In Figures 1 and 2, 1 is the front mirror plate, 2 is the body plate, 3 is the rear mirror plate, 4 is the small smoke chamber, 5.5 is the side smoke pipe, 6.6 is the water-cooled wall pipe,
7.7 is a downcomer pipe, 8.8 is a header, 9 is a fixed grate, 1
0 is the water level gauge connection port, 11 is the pressure gauge connection port, 12 is the safety valve connection port, 13 is the main steam valve connection port, 14 is the blowout valve connection port, 15 is the manhole, 16.16 is the lifting fitting, 17
is the flue, 18 is the economizer, 19 is the motor, 20 is the suction ventilator, 21 is the damper, 22 is the chimney, the eel is the base, U is the stoker surface, 5 is the side flue, 26 is the water These components are an application of a known heat storage boiler to a coal-fired heat storage boiler.

The combustion gas of the coal is then transferred to the stoker surface U by the suction fan 20 operated by the rotation of the motor 19.
From there, through the side flue 5 and the small smoke chamber 4, a plurality of side smoke pipes 5.
5, passes through a flue 17, an economizer 18, a suction fan 20, and is sent to a chimney 22.

The mizudate is heated by the combustion gas of the coal and generates steam. The water level can be changed from the high water level 26a to the low water level 2 by adjusting the water supply as described below.
Adjustment is controlled within a range of 6d.

Hereinafter, a method of controlling a coal-fired heat storage boiler according to the present invention will be explained using the water supply piping system and its control diagram shown in FIG. 3.

In Figure 3, the nail, 28 is the steam valve, 4 is the steam flow rate needle, 30 is the water supply flow rate needle, 31.31' is the totalizer, 32 is the microcomputer, blades, 34 and 35 are the motor valves, A, 37 is Float switch 38 is a boiler pressure needle.

First, the output signal of the steam flow rate plan is set at a certain period, for example, 1
The totalization is performed every ~5 minutes using the totalizer 31, and the amount of evaporation (tons per hour) is calculated using the microcomputer.

The output signal of the water supply flow rate needle 30 is integrated by the totalizer 31' in the same way as in the steam flow rate plan described above, and the water supply amount (tons per hour) is calculated by the microcomputer.

Next, the microcomputer 32 controls the motor valve 3 so that water is supplied in inverse proportion to the amount of steam flow generated.
3. Appropriately control the opening degree.

As a result, when the boiler generates a lot of steam, less water is supplied, and when less steam is generated, a large amount of water is supplied.

That is, the amount of water supplied to the boiler increases or decreases in inverse proportion to load fluctuations, and the boiler also plays the role of an accumulator, so even if the load fluctuates significantly, the amount of coal burned can be kept constant.

When the water level in the boiler reaches the highest water level 26a, the float switch is activated and the motor valve 34 is closed. Also, when the water level drops to 26b, the motor valve is opened.

When the water level in the boiler reaches the dangerous low water level of 26d, the motor valve opens to prevent dry firing, and when the water level rises to 26c, the motor valve closes, ensuring that the evaporation area in the boiler is below a certain allowable value. Water supply will be cut off to prevent this from happening.

When the water level is intermediate between the highest and lowest water levels, the motor valve 33 maintains an appropriate opening degree according to instructions from the microcomputer 32, and water is supplied appropriately according to the increase or decrease in steam generation.

The reading of the boiler pressure gauge 38 is sent to the microcomputer 32.
In addition to the steam flow rate plan and the data from the feed water flow meter 30, correction calculations are performed based on the boiler pressure.

That is, if the boiler pressure gauge 38 rises above the set value, the water supply amount is increased. Also, if the boiler pressure needle falls below the set value, the water supply amount is reduced.

FIG. 4 is a graph showing the relationship between the amount of steam generated and the amount of water supplied, in which the broken line shows the amount of water supplied and the solid line shows the change in the amount of steam.

According to the present invention, water supply is reduced in inverse proportion to the amount of evaporation when there is an overload such as on a ridge, and a large amount of water is supplied when the load is light, thereby reducing the large amount of heat retained in the boiler body that operates as an Akiemulator. Depending on the amount of water, it is possible to quickly respond to large and sudden changes in load, and during this time combustion is always kept approximately constant, allowing the boiler to exhibit its original maximum efficiency.

〔Effect of the invention〕

Since the present invention is structured like a ridge, it is possible to provide a control method suitable for a high-performance coal-fired heat storage boiler that has the performance of an accumulator that generates much more steam than the rated value. It is something.

Note that the configuration of the present invention is not limited to the embodiment on the ridge, and the shape, dimensions, etc. of each component can be freely changed within the scope of the purpose of the present invention, and the present invention It encompasses all of the above.

[Brief explanation of drawings]

1 and 2 are a cross-sectional front view and a cross-sectional side view showing one embodiment of a coal-fired heat storage boiler according to the present invention, FIG. 3 is a cross-sectional side view, piping system and control circuit diagram thereof, and FIG. is a graph showing the relationship between the amount of steam generated and the amount of water supplied.

Claims (1)

[Claims] A control method for a coal-fired thermal storage boiler, characterized in that combustion is always kept constant, water is supplied in approximately inverse proportion to the required evaporation amount, and steam is supplied in immediate response to load fluctuations.