JPH0421091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cleaning soot from a multi-tubular once-through boiler.

Conventionally, both the upper header and the lower header are formed in an annular shape, and the upper and lower headers are connected by a number of vertical water pipes, and these water pipes are arranged as two concentric annular water pipe rows spaced apart in the radial direction. In a multi-tube once-through boiler where a combustion gas passage is formed between the inner annular water tube row and the outer annular water tube row, if soot adheres to the water tubes, the combustion chamber side etc. can be cleaned. However, it had the disadvantage that it was impossible to completely clean the combustion gas passage.

The object of the present invention is to provide a soot cleaning method that eliminates the above-mentioned drawbacks and can also completely clean the combustion gas passage.

Hereinafter, a description will be given based on the drawings. A conventional multi-tube once-through boiler has a configuration shown in FIG. 1. That is, both the upper header 1 and the lower header 2 are annular. These upper and lower headers 1 and 2 are connected to both the upper and lower ends of a large number of vertical water pipes, and these water pipes are arranged in two concentric annular water pipe rows 3 and 4 at intervals in the radial direction. .
A combustion gas passage 5 is formed between the inner annular water tube row 3 and the outer annular water tube row 4, and a combustion device 6 is provided inside the upper header 1. If desired, this combustion device 6 can also be placed in the space formed inside the lower header 2.

In the figure, 7 is a combustion chamber formed inside the inner annular water tube row 3. Both ends of each of the water tubes in the annular water tube rows 3 and 4 become diameter-reduced portions 8, which are fitted and welded into the tube plates of the upper header 1 and the lower header 2, respectively.

In implementation, openings (not shown) extending over the entire length of the tubes are provided in the inner annular water tube row 3 to communicate the combustion chamber 7 and the combustion gas passage 5, and the outer annular water tube row 4 an opening along the entire length of the tube (not shown)
may be provided so that the combustion gas passage 5 and a flue (not shown) communicate with each other so that the combustion gas flows horizontally through the combustion gas passage 5. may also be configured to flow vertically. 9 in the figure is a casing.

In the multi-tubular once-through boiler as described above, the present invention is constructed as shown in FIG. That is, by penetrating the upper plate 1A and lower plate 1B of the upper header 1,
A plurality of guide pipes 10 for inserting soot cleaning means are provided in the combustion gas passage 5. The soot cleaning means consists of a high-pressure water cleaning tool with a nozzle attached to its tip. These guide pipes are usually sealed with appropriate sealing means to prevent combustion gas from escaping to the outside.
Of course, when applying the soot cleaning means from the outside, the seal of the guide pipe is temporarily opened.

Next, to explain the soot cleaning method, operate the soot cleaning means to insert a high-pressure water cleaning tool with a nozzle attached to the tip into the combustion gas passage 5 through the guide pipe 10, and the nozzle cleans the water pipe to be cleaned. The cleaning means is moved up and down along the axial direction of the water pipe so as to face the part, and in this way, the water pipe is entirely cleaned with high pressure water jetted from the nozzle.
In this case, it is desirable that the nozzle be installed so that high-pressure water is sprayed horizontally.

By the way, the guide pipe 10 is caused by combustion gas.
To prevent burnout, as shown in Figure 3,
It is desirable that the wall thickness of the guide pipe 10 is reduced by cutting a portion of the combustion gas passage 5 that is covered with the refractory 11. If you do this, the thermal stress will be concentrated at the boundary between the wall thickness and burn off from there.
Accidents such as damage to parts inside the upper header 1 do not occur.

As explained above, the present invention can provide a method that allows easy cleaning of soot from the combustion gas passage of a multi-tubular once-through boiler, which has been considered impossible in the past.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view, Figure 2 is a partially enlarged sectional view,
FIG. 3 is a further enlarged sectional view. 1... Upper header, 1A... Upper plate, 1B... Lower plate, 2... Lower header, 3... Inner annular water tube row, 4... Outer annular water tube row, 5... Combustion Gas passage, 6... Combustion device, 7... Combustion chamber, 7... Reduced diameter portion of water pipe, 9... Casing, 10... Guide pipe.

Claims (1)

[Claims] 1. A multi-tubular flow through system in which upper and lower annular headers 1 and 2 are connected by two inner and outer annular water tube rows 3 and 4, and a combustion gas passage 5 is formed between these water tube rows 3 and 4. In a boiler, the upper plate 1 of the upper header 1
A and the lower plate 1B, and a plurality of guide pipes 10 whose lower ends reach into the combustion gas passage 5 are installed in a ring shape along the upper header 1, and using such guide pipes 10, A soot cleaning means consisting of a high-pressure water washer equipped with a nozzle is inserted into the combustion gas passage through the guide pipe, and the soot cleaning means is inserted into the water pipe so that the nozzle faces the water pipe section to be cleaned. an operation of moving the pipe up and down along the axial direction of the water pipe, and an operation of cleaning the entire water pipe with high-pressure water from the nozzle during this operation;
and a method for cleaning soot in a multi-tubular once-through boiler, comprising the steps of repeatedly applying each of these operations to each guide pipe 10 over the entire circumference of the combustion gas passage 5.