JPS63290304A - Boiler water feed method - 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] [Field of Industrial Application] The present invention relates to a boiler water supply method that aims to prevent corrosion of an economizer and save power by supplying heat retained in boiler exhaust gas to boiler feed water by heat exchange. The present invention relates to a boiler water supply method that prevents corrosion and saves power by preheating the economizer inlet water supply temperature to about 50 to 60°C in a steam boiler that uses fuel with low sulfur content, such as kerosene or light oil.

[Conventional technology]

In boilers that use fuel containing sulfur, when the gas side pipe wall temperature of the economizer falls below the sulfuric acid dew point temperature of the combustion gas, the sulfur dioxide gas in the exhaust gas combines with water to become sulfuric acid, which reduces heat transfer on the gas side of the economizer. corrodes surfaces. In this case, corrosion can be prevented by raising the temperature of the gas side pipe wall of the economizer above the sulfuric acid dew point temperature.

The sulfuric acid dew point temperature varies depending on the sulfur content in the fuel.

For example, with fuels with low sulfur content such as A-heavy oil, kerosene, and light oil, if the economizer inlet water supply temperature is 50 to 60°C, corrosion of the economizer will hardly occur.

Conventionally, when preheating feed water to about 50 to 60 DEG C., a steam type feed water preheater is generally used, as shown in FIG. That is, water at room temperature from the feed water tank 1 is pressurized by the feed water pump 2 and enters the steam type feed water preheater 3, while steam generated in the boiler 4 is guided to the steam type feed water preheater 3 through the steam piping 5 and is Heat indirectly. The preheated feed water reaches a predetermined temperature and enters the economizer B, exchanges heat with the boiler exhaust gas, becomes even hotter due to the heat retained in the boiler exhaust gas, and enters the boiler 4. On the other hand, in the steam-type feed water preheater 3, the steam loses heat to the feed water, becomes drain, and is discharged to the outside of the system through the drain trap 7. The water supply control is
This is done by driving and stopping the water supply pump 2.

Conventionally, as shown in FIG. 6, a system is known in which an injector is used as an emergency water supply device and is manually operated. That is, the water supplied from the water tank 1 is normally pumped to the boiler 4 by the water pump 2. When the water supply pump 2 is forced to stop for some reason, the water supply pump 2 is stopped, the manual valve 8 is manually fully opened by a person, and the steam generated from the boiler 4 is supplied to the injector 10 through the steam pipe 5. Boiler 4 sucks up the feed water
The water supply is controlled by manually adjusting the manual valve 11 of the water supply pipe while monitoring the water level with a water level gauge (not shown) of the boiler 4. In this way, the injector 10 is used as an emergency water supply device.

[Problem that the invention seeks to solve]

However, in the conventional system shown in Figure 5 above, the steam-type feed water preheater is expensive, and the steam drain is discarded even though it still has about 15% of the heat of the steam. , there is a problem that heat loss cannot be ignored.

Furthermore, in the conventional system shown in FIG. 6 above, the injector is used only in an emergency.

The present invention has been made in view of the above points, and can solve the above problems and further save power, and has a relatively simple configuration in which the injector is used as a normally used water supply device, and is capable of preventing corrosion of the economizer. The purpose of the present invention is to provide a boiler water supply method that can prevent heat loss, prevent heat loss, and save power.

[Means and effects for solving the problem] The boiler water supply method of the present invention will be described with reference to FIG. When preheating the boiler feed water in the steam boiler 4 which has an economizer 6 that supplies water to the boiler and whose boiler feed water is on-off controlled, an injector 10 is provided in the inlet water supply piping of the economizer B, and the steam generated from the boiler 4 is injected into the injector. is supplied via the steam electric valve 12 to preheat the feed water sucked up by the injector,
This preheated boiler feed water is passed through the economizer 6 to the boiler 4.
The boiler water supply is controlled by fully opening and opening the steam electric valve 12.

When the water level in the boiler 4 falls and water needs to be supplied to the boiler, the steam electric valve 12 is fully opened, and the steam generated in the boiler is supplied to the injector 10, and the water supplied from the water tank 1 is sucked up and passed through the economizer 6. to boiler 4,
Supplied. When the water level of the boiler 4 rises and the boiler no longer requires water supply, the steam electric valve 12 is fully closed. Then, the supply of steam, which is a driving source, to the injector 10 is stopped, and the water supply is also stopped.

As described above, the steam supplied to the injector 10 as the power for sucking up the feed water is mixed with the sucked up feed water and supplied to the boiler 4, so the temperature of the feed water increases. When tested with an existing injector, the water supply outlet temperature rose by 30 to 50 degrees Celsius compared to the water supply inlet temperature, resulting in a temperature of 50 to 50 degrees Celsius.
The temperature reached 60℃. Therefore, if the injector is installed on the inlet side of the economizer, it can be used as a corrosion prevention device.

Conventionally, water supply control is controlled by the opening degree of the manual valve 11, but this is set to the boiler maximum capacity or higher, and a steam electric valve 1 is installed in the middle of the drive steam piping that is supplied to the injector.
By fully opening and fully closing this steam electric valve 12, water supply is supplied to the boiler 4 or stopped, and the function is similar to that of driving and stopping a water supply pump.

〔Example〕

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIG. However, unless there is a specific description, the shapes of the components described in this example, their relative positions, etc. are not intended to limit the scope of the present invention to these, but are merely illustrative examples. Only.

4 is a boiler, 6 is an economizer, and an injector 10 is provided in an inlet water supply pipe 13 of the economizer population, and a water supply pipe 14 from a water supply tank 1 is connected to this injector via a manual valve 11. On the other hand, a steam pipe 5 from the boiler 4 is connected to an injector 10 via a steam electric valve 12.

The amount of water supplied to the injector 10 can be adjusted by the opening degree of the manual valve 11, so adjust the opening degree so that it is slightly larger than the maximum amount required for the boiler 4. When water supply is required, the steam electric valve 12 is fully opened, and the steam generated in the boiler is supplied to the injector 10, and the water supply from the water tank 1 is sucked up and supplied to the boiler 4 through the economizer 6.

When the water level of the boiler 4 rises and the boiler no longer requires water supply, the steam electric valve 12 is fully closed. Then, the supply of steam, which is a driving source, to the injector 10 is stopped, and the water supply is also stopped.

Note that when there is no water in the boiler 4, there is no generated steam in the boiler 4, so the injector 10 cannot be driven. For such a case, a water supply pump for filling with water is required. The head and capacity of this water supply pump may be small, and even if water flows into this water supply pump while the water supply pump is stopped, it may be installed in series with the injector as long as there is little resistance.

To explain this with reference to FIG. 2, a water supply pump 15 for filling water is provided in the water supply pipe 14 at the inlet of the injector 10, and this water supply pump 15 is operated only when filling with water, and after filling with water is completed, this water supply pump 15 is stopped. Steam is generated in the boiler 4, and water is then supplied by the injector 10.

FIG. 3 shows another embodiment. In this case, the water filling pump 15 is provided in parallel with the injector 10. Note that 16 is a check valve. The water filling pump 15 may be a pump having the capability of a boiler water supply system as an emergency water supply system in the event of an injector failure.

When the driving steam source is stopped, hot water slowly flows into the injector 10 from the overflow port. If discarding this hot water is an energy saving problem, the overflow pipe 17 may be connected to the inlet side of the manual valve 11 on the inlet side of the injector 10, as shown in FIG.

〔Effect of the invention〕

When using a fuel with low sulfur content such as A heavy oil, kerosene, or light oil in a boiler equipped with an economizer, in order to prevent sulfuric acid corrosion on the boiler exhaust gas side of the economizer,
All you need to do is raise the temperature of the water supply entering the economizer by 30 to 40 degrees Celsius.As described above, the present invention has a relatively simple configuration of arranging and using an injector, and is inexpensive and can be used to increase the water supply. All of the steam is recovered together with the water supplied to the boiler, and there is no need to constantly use a water pump with an electric motor, resulting in the effect of saving power.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an apparatus for implementing the boiler water supply method of the present invention, FIGS. 2 to 4 are explanatory diagrams of main parts showing other examples of the apparatus for implementing the method of the present invention, FIG. 6 is an explanatory diagram of a conventional boiler feed water preheating device. 1... Water supply tank, 2... Water supply pump, 3... Steam type water supply preheater, 4... Boiler, 5... Steam piping,
6...Economizer, 7...Drain trap, 8.
...Manual valve, 10...Injector, 11...Manual valve, 12...Steam electric valve, 13...Inlet water supply piping, 1
4...Water supply piping, 15...Water supply pump for filling water,]
6... Check valve, 17... Overflow piping application Person Kawaju Refrigeration Co., Ltd. Figure C Figure 4

Claims (1)

[Claims] 1 When preheating the boiler feed water in a steam boiler that has an economizer that exchanges heat between the boiler exhaust gas and the boiler feed water to give the heat retained in the boiler exhaust gas to the boiler feed water, and in which the boiler feed water is controlled on and off, the economizer inlet An injector is provided in the water supply piping, and steam generated from the boiler is supplied to this injector via a steam electric valve to preheat the feed water sucked up by the injector, and this preheated boiler feed water is supplied to the boiler via an economizer,
A boiler water supply method characterized in that boiler water supply is controlled by fully opening and fully closing the steam electric valve.