JP2782414B2 - Multi-tube type once-through boiler with multiple upper headers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-tube once-through boiler having a plurality of upper headers.

[0002]

2. Description of the Related Art In a multi-tube once-through boiler comprising a large number of water pipes and upper and lower headers, boiling water is heated when the water pipes are heated, and part of the boiling water together with the steam is transferred to a steam separator. As a result, it is not overheated even in a portion higher than the water level at the top of the water pipe. However, when the heat load factor is low, the boiling height is low, and the boiling water may not reach the upper part of the water pipe, and the upper part of the water pipe is overheated.
When there is a water pipe with a different heat load factor, the water pipe water level is the same, so that a water pipe with a high heat load will carry over, and a water pipe with a low heat load will generate water pipe overheating. In the case of a multi-tube once-through boiler, all of the heating pipes need to be riser pipes, but if the heat load rates of the water pipes are different, the boiling water boiled in the water pipe with the higher heat load rate will be replaced by water with a lower heat load rate. It is necessary to set the water level to a position lower than the ideal water level to prevent overheating of the water pipes and to suppress boiling, since the water pipes that are sent into the pipes and the heat pipes with a low heat load rate may become downcomers may be generated. there were.

[0003]

An object of the present invention is to provide a boiler having an arrangement in which the heat load factors of water tubes are different from each other. The purpose of the present invention is to prevent overheating of the upper portion and the occurrence of carryover from a water pipe having a high heat load rate, and to prevent internal circulation of boiling water from a water pipe having a high heat load rate to a water pipe having a low heat load rate.

[0004]

A number of water pipes connecting the upper and lower headers are arranged between an upper header and a lower header, and water is supplied from a water supply pipe connected to the lower header to the upper header. The steam and boiling water are sent to the steam inlet of the steam separator by the connected pipe, and only the steam after the gas-liquid separation is taken out.The boiling water is returned to the lower header, and the steam / bore separator and the lower header are connected. A multi-tube once-through boiler provided with a water level detection device between them, in a case where the heat load factor of the water pipes is different, when a plurality of upper headers are provided according to the difference of the heat load factor with respect to the water pipes, A steam-water separator with steam inlets of different heights in the number of upper headers is provided near the header on the smaller side, and the connection is connected to the upper header on the water pipe side with a high heat load factor. Pipe to upper steam inlet, upper header on water pipe side with low heat load factor Connected communication tube is connected to a lower portion of the steam inlet.

[0005]

[Function] A group of water tubes having different heat load factors is divided into different headers according to the magnitude of the heat load factor, and each of the headers is connected to a steam separator, so that there is a difference in boiling for each divided water tube. . In a water pipe with a high heat load and a large boiling point, a large amount of water reaches the upper header and the amount of water-water mixed fluid and the water content flowing from the header into the steam separator increase. On the contrary, when the heat load ratio is low, the passing pressure difference becomes small accordingly. When a water level detection device is provided between the steam separator and the lower header and the reference water level is set in the steam separator, the pressure in the upper header is large due to the pressure difference caused by the amount of water-water mixed fluid and the water content. When the water pipe water level is low, the water pipe water level rises when the pressure in the upper header is low, and the water pipe water level is autonomously adjusted to an appropriate water level. By dividing the upper header according to the load factor, all the water pipes can be constantly adjusted to a constant boiling level, thereby preventing overheating and carryover of the water pipes.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a boiler. One lower header (1) and two upper headers AB (2A) and (2B).
The vertical water pipe group (3) is installed between the upper and lower headers. The water supplied to the lower header is turned into steam and boiling water by the water pipe being heated by the burner (4), and is passed through the connecting pipe A (5A) or the connecting pipe B (5B) to form a steam-water separator. It is sent to (6) where it is gas-liquid separated and only the vapor is taken out, and the boiling water is returned to the lower header. The water level detection device (7) is connected to the steam separator and the lower header, and controls the water supply so that the water level becomes constant.

A connecting pipe A is connected to an upper header A connected to a group of water pipes near the burner, and a connecting pipe B is connected to an upper header B connected to a group of water pipes far from the burner. . The steam separator is installed near the upper header B, and the steam inlets A (8A) and B (8
B), the steam reaching the upper header A is introduced into the steam separator from the steam inlet A (8A) by the connecting pipe A, and the steam reaching the upper header B is connected to the connecting pipe B. Is introduced into the steam separator through the steam inlet B (8B).

When heating is performed, the heat load factor on the side near the burners of the water tube group is high, the water tubes boil violently, and a lot of boiling water is lifted to the upper header A (2A), and the burners of the water tube group are burned. Since the heat load factor is low on the side farther away, the amount of evaporation is small, and the amount of boiling water lifted to the upper header B is small. In the case of the upper header A, the boiling water is sent to the steam separator through the connecting pipe A (5A), but the height difference between the upper header and the steam separator is large, and the steam separator is used. The amount of boiling water sent to the furnace is reduced. In addition, when heating was performed, the upper header A
A pressure difference is generated between the upper header B and the upper header B, and the water level connected to the upper header A side where the pressure is increased has a low water level, and the water level connected to the lower header B side having a low pressure is equal to the water level. Get higher.

[0009]

By implementing the present invention, it is possible to set a water level according to the heat load rate for each water pipe even in a boiler having a different heat load rate of the water pipes, thereby preventing carryover. Water tube overheating can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower header 2A Upper header A 2B Lower header B 3 Vertical water pipe group 4 Burner 5A Communication pipe A 5B Communication pipe B 6 Steam separator 7 Water level detector 8A Steam inlet A 8B Steam inlet B

Claims (1)

(57) [Claims] 1. A plurality of water pipes for connecting upper and lower headers are disposed between an upper header and a lower header, and a water supply pipe is connected to the lower header and water is supplied to the upper header, and a connecting pipe is connected to the upper header. This is a multi-tube once-through boiler in which steam containing boiling water is sent to the steam inlet of the gas-water separator, and only the steam after gas-liquid separation is taken out. In this case, multiple upper headers shall be provided according to the difference in the heat load factor for the water pipes, and a steam separator shall be installed near the upper header on the water pipe side with the lower heat load factor. The long connecting pipe connected to the upper header on the water pipe side with the higher heat load factor is connected to the upper steam inlet port and to the upper header on the water pipe side with the lower heat load rate. Upper header, characterized by a short connecting pipe connected to the lower steam inlet Multi-tube type once-through boiler with multiple.