JP3397292B2 - Boiler economizer cleaning equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiler economizer cleaning device.

[0002]

2. Description of the Related Art A boiler economizer is installed in a flue of a boiler and preheats feed water to the boiler by heat of combustion exhaust gas emitted from the boiler. Since the combustion exhaust gas contains soot, the soot of the combustion exhaust gas adheres to the surface of the economizer in contact with the combustion exhaust gas, and the adhered soot causes a decrease in the heat exchange rate and causes corrosion. Need to do. For this reason, inside the flue, an injection pipe for injecting can water is placed on the surface of the economizer located in the flue, and this ejection pipe and the boiler can are connected by a connecting pipe having an on-off valve in the middle. Before cleaning, the on-off valve was opened, the boiler can water was led to the injection pipe through the connecting pipe, and the can water was injected as cleaning water into the economizer for a predetermined period of time.

The cleaning of the economizer is adjusted by adjusting the time of spraying the cleaning water. If the spraying time is shortened, the cleaning becomes insufficient, and if the spraying time is lengthened, a large amount of can water is used. Therefore, the problems described below occur. When the amount of injection of canned water increases and the water level in the boiler decreases, the temperature of the canned water decreases when a large amount of water is supplied, and the temperature of the wash water injected to the economizer also decreases, so it is used for evaporation. The amount of heat generated is reduced and the amount of steam generated is reduced. If the water level in the boiler drops significantly due to lack of water supply, the boiler will stop due to an abnormal water level. Further, when the inside of the flue is cooled by the sprayed cleaning water, the combustion exhaust gas sent through the flue is often condensed and corroded in some cases.

[0004]

The problem to be solved by the present invention is to significantly reduce the amount of steam generated when the economizer is cleaned and to stop abnormally due to a large decrease in the water level in the boiler. And to prevent increased flue gas cooling from increasing flue gas condensation and corrosion.

[0005]

[Means for Solving the Problems] In an economizer cleaning device provided in a flue of a boiler, a cleaning water pipe having an opening / closing control valve in the middle and injecting can water in the boiler onto the surface of the economizer, If it is necessary to clean the economizer with a counting device that counts the opening and closing times of the open / close control valve and the number of times the open / close control valve is opened for a predetermined time
There is provided control means for performing the cleaning of the economizer in a divided manner by repeating the control for opening and closing the cleaning water pipe for the set cleaning time t12 and closing it for the set cleaning stop time t22 a predetermined number of times.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic explanatory view schematically showing an embodiment of the present invention,
FIG. 2 is a flowchart in one embodiment, and FIG. 3 is a time chart in one embodiment. Reference numeral 1 is a boiler, 2 is a boiler can body provided therein, 3 is a combustion device for heating the can body, 4 is a blower for supplying air to the combustion device,
The saturated steam generated in the can body 2 by the heating of the combustion device 3 is supplied to a predetermined supply point from a steam extraction pipe 5 having a steam stop valve Vl.

A flue 6 communicates with the lower part of the boiler 1, and the combustion exhaust gas that heats the can body rises in the flue 6 and is discharged. An economizer 7 is provided in the flue, and the water supplied to the can body 2 is pressurized by a water supply pump P and is preheated by exchanging heat with the combustion exhaust gas rising in the flue when flowing through the economizer. , Is pushed into the bottom of the boiler can through the water supply pipe 8. A normally open U-shaped drain pipe 9 is provided at the bottom of the flue 6.

In the flue 6, above the economizer 7, an injection pipe 11 for injecting cleaning water is provided on the surface of the economizer, and this injection pipe and the lower part of the can body are provided with an opening / closing control valve V in the middle thereof.
It connects with the connecting pipe 12 which has 2. The jet pipe and the connecting pipe constitute the wash water pipe 10. When the boiler is operated, the combustion exhaust gas that has heated the can body 2 enters the flue 6 from the boiler and rises in the flue. Soot adheres to the inner wall surface of the flue and the surface of the economizer 7. It is necessary to perform cleaning with the water pipe 10.

A pressure gauge 13 for detecting the pressure inside the can body 2 is provided outside the boiler, and the pressure gauge outputs the pressure value inside the can body to the control device 14. The control device 14 is the opening / closing control valve V2.
Is also connected, and controls the opening / closing of the opening / closing control valve V2 to control the cleaning of the economizer.

The control device 14 controls each part as shown in the flow chart of FIG. 2 to clean the economizer 7.
First, the combustion time T, which is the time during which the combustion device 3 is operating
1 is counted, and the combustion time T1 is the combustion set time T2
It is determined whether (for example, 8 hours) has been reached. In this determination, if the combustion time T1 is less than the combustion set time T2, cleaning is not performed until the combustion time T1 reaches the combustion set time T2. If the combustion time T1 is the combustion set time T2 or more, the cleaning output is The cleaning process is started. Before actually starting the cleaning, it is determined based on the output of the pressure gauge 13 whether or not the vapor pressure P1 is equal to or higher than the cleaning pressure P2 (for example, 4 kg / cm2) (step ST1). If the vapor pressure P1 is equal to or higher than the cleaning pressure P2, then it is determined whether the combustion device is burning (step ST2). If the steam pressure P1 is less than the cleaning pressure P2 or if the combustion device has not combusted in the determinations in steps ST1 and ST2, and if the cleaning water is being injected, the opening / closing control valve V2 is closed (step ST3). After resetting the cleaning time t11 (step ST4) and waiting, if the steam pressure P1 is equal to or higher than the cleaning pressure P2 and combustion is being performed, the opening / closing control valve V2 is opened to clean the economizer 7 (step ST5).

The cleaning of the economizer 7 will now be described. The opening / closing control valve V2 of the cleaning water pipe 10 is opened,
Cleaning is performed by injecting the cleaning water for the set cleaning time t12 and then closing the opening / closing control valve V2 for the set cleaning stop time t22 a predetermined number of times. At the same time when the opening / closing control valve V2 is opened in step ST5, the counting of the cleaning time t11 is started by a built-in counting device (step ST5).
6), the cleaning time t11 is the set cleaning time t12 (for example, 10
Second) is determined (step ST7). If the cleaning time t11 is less than the set cleaning time t12 in the determination of step ST7, if the steam pressure P1 is equal to or higher than the cleaning pressure P2 and combustion is performed, cleaning is performed until the cleaning time t11 reaches the set cleaning time t12. When the cleaning time t11 becomes equal to or longer than the set cleaning time t12, the opening / closing control valve V2 is closed and the cleaning is stopped (step ST8), and the cleaning time t11 is reset (step ST9).

Next, the cleaning frequency t31 is counted (+1) (step ST10), and it is determined whether or not the cleaning frequency t31 has reached the set cleaning frequency t32 (3 times in this embodiment) (step ST11). . If the number of washings t31 has reached the set number of washings t32 in the determination in step ST11, the combustion time T1 and the number of washings t31 are reset (step ST15).
Then, the cleaning is completed, and if the set number of times of cleaning is less than t32, the cleaning process is continued.

Even when the cleaning process is continued, the opening / closing control valve V2 is closed in step ST8, so that the cleaning water injection is stopped and the cleaning stop time t21 is the set cleaning stop time t22 (for example, 5 minutes). Continue to stop washing until reaching. In step ST12, counting of the cleaning stop time t21 is started, and it is determined whether or not the cleaning stop time t21 has reached the set cleaning stop time t22 (step ST13).
The set cleaning stop time t22 is set to the time until the cleaning water sprayed to the economizer is discharged from the drain pipe 9, the cleaning water adhering to the surface of the economizer is also evaporated, and the inside of the flue returns to the normal state. Keep it. This step ST13
If the cleaning stop time t21 is less than the set cleaning stop time t22, the cleaning is stopped until the cleaning stop time t21 reaches the set cleaning stop time t22, and if the cleaning stop time t21 is the set cleaning stop time t22 or more, the cleaning is stopped. The stop time t21 is reset (step ST14), the process returns to step ST1 and the cleaning process is performed again.

As described above, the washing stop step is provided in the middle of the economizer washing step, and the washing water is sprayed in a plurality of times, so that a large amount of can water is not used at one time. It is possible to prevent the temperature of the water in the can and the water level in the can from dropping significantly. Further, since the cooling by the cleaning liquid in the flue is also suppressed, it is possible to prevent the combustion exhaust gas from condensing in the flue to increase and to cause corrosion.

Since the economizer is cleaned while the combustion device 3 and the blower 4 are operating, the combustion exhaust gas from the boiler is sent during the cleaning process, and the cleaning wastewater injected to the economizer is discharged from the boiler. To prevent you from getting inside,
Further, since the combustion exhaust gas is sent, the cleaning water adhering to the surface of the economizer is blown off from the economizer surface. Therefore, it is possible to prevent corrosion of the boiler can and the economizer due to the cleaning drainage of the economizer.

[0016]

EFFECTS OF THE INVENTION By carrying out the present invention, a large amount of canned water is used while performing sufficient cleaning, the temperature of the canned water is lowered, and the amount of steam generated is greatly reduced. Prevents the boiler from stopping abnormally due to a large drop in the water level, and prevents the flue gas from being cooled by the injected cleaning water, causing the condensation of the combustion exhaust gas sent to the flue gas to increase and to cause corrosion. can do.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of the operating condition of the boiler according to the present invention.

FIG. 3 is a time chart of an example of the operating condition of the boiler according to the present invention.

[Explanation of symbols]

1 boiler 2 boiler cans 3 Boiler combustion device 4 blower 5 Steam extraction pipe V1 steam extraction pipe steam stop valve 6 flue 7 Economizer installed in the flue 8 water supply pipe 9 Drain pipe 10 Washing water piping 11 Cleaning water pipe injection pipe 12 Connecting pipe for cleaning water piping V2 Wash water pipe opening / closing control valve 13 Pressure gauge (pressure detection means) 14 Control device (control means)

Claims (2)

(57) [Claims] 1. A cleaning device for an economizer provided in a flue of a boiler, which has an opening / closing control valve in the middle thereof, and a cleaning water pipe for injecting can water in the boiler onto the surface of the economizer,
When the opening / closing time of the opening / closing control valve and the number of times the opening / closing control valve is opened for a predetermined time are counted, and when the economizer needs to be cleaned, the opening / closing control valve of the cleaning water pipe is set to the cleaning time t12. And a control means for performing the cleaning of the economizer in a divided manner by repeating the control of opening for a predetermined time and closing for the set cleaning stop time t22 a predetermined number of times.
The set cleaning stop time t22 is the economizer.
The cleaning water sprayed to the part is discharged, and the surface of the economizer is discharged.
The cleaning water that had adhered also evaporates and returns the flue to its normal condition.
The cleaning device for the boiler economizer, which is characterized by the time it takes to reach the end . 2. The boiler economizer according to claim 1,
In the cleaning device, is the combustion device of the boiler burning?
Cleaning the economizer by providing a means to determine whether or not
Sometimes a step is needed to determine if the combustion device is burning.
If the combustion device is not burning,
Of the boiler, which is characterized by not being washed
Cleaning device for economizer.