JPH0933001A - Boiler having water-cooled tube arranged in front of burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of NOx and CO by a method wherein a water- cooled tube through which water fed to a boiler forcibly passes is arranged in such a state to approach the combustion part of a burner. SOLUTION: Water tubes through which upper and lower headers 1 and 2 are connected together are coupled together through a fin to form a pair of parallel water tube wall surfaces. A water tube for one thing approaching a burner 5 forms a water- cooled tube 4 and other tubes form a vaporizing tube. Upper and lower headers connected to the water-cooled tube 4 form a water-cooled tube upper header 8 and a water-cooled tube lower header 9, respectively. A steam separator 10 and the upper header 1 are connected together through a steam communication pipe 11 and the steam separator and the lower header 2 are connected together through a downcast pipe 12. A water feed line 3 is connected to the water-cooled tube lower header 9 and the water-cooled tube upper header 8 and the steam separator 10 are connected together through a feed water communication pipe 13. The temperature of combustion gas by a burner 5 is rapidly reduced to approximate 1300 deg.C by the watercooled pipe 4. Since a time in which combustion gas resides at a high temperature is shortened, an amount of generating NOx and CO can be reduced.

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 structure for heating a water pipe by intersecting combustion gas from a burner provided on the side surface of the water pipe group with the water pipe.
The present invention relates to a boiler can structure that enables low x and low CO.

[0002]

2. Description of the Related Art An upper pipe header is arranged at an upper part and a lower pipe header is arranged at a lower part, and a plurality of water pipes are connected between the upper and lower pipe headers. There is a multi-tube once-through boiler in which the combustion gas stays at a high temperature for a short time by keeping the burner and the water pipe close to each other.

In order to suppress the generation of NOx and CO, which have been particularly problematic in recent years, the temperature of the combustion gas is set to 13 at an early stage.
It is necessary to lower the temperature to around 00 ° C. Since the boiler has a water pipe near the burner, the combustion gas temperature can be lowered in a relatively short time.

[0004]

The problem to be solved by the present invention is to heat a water pipe by flowing combustion gas from a burner provided on the side surface of the water pipe group so as to intersect the water pipe group. In NOx, by reducing the flame temperature to the target temperature in a shorter time, NOx
And to provide a boiler capable of reducing the generation of CO.

[0004]

[Means for Solving the Problems] An upper pipe header is arranged at an upper part and a lower pipe header is arranged at a lower part. A plurality of water pipes are connected between the upper and lower pipe headers, and a burner provided on a side surface portion of the water pipe intersects the water pipe. This is a boiler that heats a water pipe by flowing combustion gas in a certain direction.A steam communication pipe is connected between a steam water separator that separates steam and boiling water to extract only steam, and a steam communication pipe is used to separate steam and water. In the multi-tube once-through boiler, in which the boiling water separated by the steam separator is circulated to the lower header by connecting a downcomer between the reactor and the lower header, it is located near the combustion part of the burner. Provide a water cooling pipe that is not in direct communication with the upper and lower pipe drawers, connect the water cooling pipe upper part and the steam separator with a water supply connecting pipe, and connect the water supply line for supplying water to the boiler to the water cooling pipe lower part. , The temperature of the combustion gas is lowered by a water cooling pipe through which water is supplied.

[0005]

When the water pipe provided close to the combustion part of the burner is a normal evaporation pipe, the water inside the evaporation pipe is heated to a high temperature, so the evaporation pipe itself is kept at a relatively high temperature.
The amount of heat absorbed from the flame also decreased, and it took time for the combustion gas temperature to drop to the target temperature.However, the water cooling pipe that forcedly passes the water supplied to the boiler is connected to the burner combustion part. When it is installed close to the water cooling pipe, the water inside the water cooling pipe is sent to the water supply connecting pipe before it reaches a high temperature and is supplied through the steam separator, so the water cooling pipe is kept at a low temperature.
The amount of heat absorbed from the combustion gas increases. Therefore, the temperature of the combustion gas can be lowered to the target temperature at an earlier stage. Further, since the combustion gas temperature is lowered in exchange for raising the feed water temperature, the heat is effectively used and the efficiency is not lowered.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
The upper head 1 and the lower head 2 are provided at the top and
Between the upper header 1 and the lower header 2, a pair of parallel wall surfaces are formed by the water pipe walls that connect the water pipes connected to the upper header 1 and the lower header 2 with fins, and are surrounded by the water pipe wall. A large number of water pipes will be installed in the closed part. At one opening of the water pipe wall, a burner 5 that burns toward a portion surrounded by the water pipe wall to flow the combustion gas in a direction intersecting with the water pipe is provided. Exhaust combustion exhaust gas from the opening.

Of the many water pipes provided, one row of water pipes provided near the burner is referred to as a water cooling pipe 4, and water pipes other than the water cooling pipe 4 are referred to as evaporation pipes 7. Of the upper header 1 and the lower header 2, the portion connected to the water cooling pipe 4 is divided from the other portion, and the upper and lower headers connected to the water cooling pipe 4 are respectively separated into the water cooling pipe upper header 8, The lower part of the water cooling pipe is 9 In the steam separator 10 for separating steam and boiling water, a steam communication pipe 11 is connected to the upper header 1, and a downfall pipe 12 is connected to the lower header. The water supply line 3 is connected to the lower water cooling pipe header 9, and the upper water cooling pipe header 8 and the steam separator 10 are connected to each other by a water supply communication pipe 13.

When the boiler is operated, the combustion gas generated by the combustion in the burner 5 first exchanges heat with the water cooling pipe 4. Since the water cooling pipe 4 is a water pipe forcing a large amount of water to flow, the water temperature does not rise so much and the water cooling pipe 4
Is kept low, the effect of cooling the temperature of the combustion gas is high, and the temperature of the combustion gas is lowered to around 1300 ° C. by the water cooling pipe 4. The combustion gas whose temperature has rapidly dropped by the water cooling pipe 4 subsequently heats the evaporation pipe 7. Steam is generated by heating canned water in the evaporation pipe 7, and the generated steam is sent to the steam separator 10 through the upper header 1 and the steam communication pipe 11 together with the lifted boiling water. Only steam is taken out by the steam separator 10, and the separated boiling water is sent to the lower head 2 through the downfall pipe 12 together with the preheated feed water sent from the feed water connecting pipe 13. The combustion exhaust gas whose temperature has been lowered by heating the evaporation pipe 7 is discharged through the flue 6.

If an adiabatic space is provided between the water cooling pipe 4 and the evaporation pipe 7 and the CO is oxidized by the water cooling pipe until the combustion gas lowered to around 1300 ° C. reaches the evaporation pipe, Occurrence can be further reduced.

[0010]

EFFECTS OF THE INVENTION By carrying out the present invention, it is possible to shorten the time for which the combustion gas temperature stays at a high temperature, and
The amount of x and CO generated can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway vertical sectional view of an embodiment of the present invention.

FIG. 2 is a partially cutaway cross-sectional view of an embodiment of the present invention.

[Explanation of symbols]

 1 Upper pipe head 2 Lower pipe pipe 3 Water supply line 4 Water cooling pipe 5 Burner 6 Flue 7 Evaporation pipe 8 Water cooling pipe Upper pipe header 9 Water cooling pipe Lower pipe header 10 Steam separator 11 Steam connecting pipe 12 Precipitation pipe 13 Water connecting pipe

Claims (2)

[Claims] 1. An upper pipe header is arranged at an upper part and a lower pipe header is arranged at a lower part, and a plurality of water pipes are connected between the upper and lower pipe headers, and a combustion gas is crossed with the water pipe by a burner provided on a side portion of the water pipe. Is a boiler that heats the water pipe by flowing the steam.The steam water separator separates steam from boiling water and extracts only steam. By connecting a water pipe from the water supply line to the lower water pipe by connecting a water pipe to the lower water pipe and connecting the water supply line to the lower water pipe, the boiling water separated by the water water separator is connected to the lower water pipe. In a multi-tube once-through boiler that circulates to the upstream side, a water cooling pipe independent of the upper and lower pipe headers is provided near the combustion part of the burner, and the upper part of the water cooling pipe and the steam separator are connected by a water supply connecting pipe. Connect the water supply line to the boiler to supply water to the boiler, not to the steam separator. Boiler provided with a cooling water pipe before the burner, characterized in that connected to the tube bottom. 2. The boiler according to claim 1, wherein a plurality of water cooling pipes are provided, the upper part of the water cooling pipe is connected to the upper water cooling pipe header, and the lower part of the water cooling pipe is connected to the lower cooling pipe of the water cooling pipe. Connect the upper part of the pipe and the steam separator with the water supply connection pipe,
A boiler equipped with a water cooling pipe in front of a burner, characterized in that the water supply line is connected to the lower part of the water cooling pipe.