JPH0480510A - Low nox combustion device - Google Patents

Abstract

PURPOSE:To get NOx reducing effect by a method wherein a combustion device is formed by an upper combustion pipe and a lower combustion pipe in which a plurality of combustion pipes having their upper surfaces acted as flame hole surfaces are alternatively arranged in a vertical direction, both sides of the upper combustion pipes are provided with a drawn portion extending outwardly and a passage between the adjoining upper combustion pipes is narrowed. CONSTITUTION:An upper combustion pipe 1 and a lower combustion pipe 2 are provided with pressure reducing walls 5 and 6 forming an auxiliary flame at each of both sides. Part of each of the walls is extended outwardly and drawn portions 7 and 8 are provided. A metering part 7 of a pressure reducing wall 5 of the upper combustion pipe 1 narrows a passage 9 between it and the metering part 7 disposed at a pressure reducing wall 5 of the upper combustion wall 5 of the adjoining upper combustion pipe 1. Then, a flow speed of combustion gas and a flow speed of secondary air in the lower combustion pipe 2 passing in the passage 9 are made fast. With such an arrangement, mixing with combustion gas and secondary air in the lower combustion pipe 2 is made superior and at the same time the combustion gas and the secondary air are accelerated at the passage 9 under a drawing action with the drawn part 7 and pass fast through a flame high temperature region, resulting in that occurrence of NOx is reduced. A part of the discharged gas in the lower combustion pipe 2 acts against the flame in the upper combustion pipe to become a low oxygen combustion to cause a flame temperature to be reduced and then a NOx reducing effect is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a low NOx combustion device designed to reduce nitrogen oxides (hereinafter referred to as NOx).

(Prior Art and Problems) Conventionally, exhaust gas recirculation (hereinafter referred to as EGR) has been known as one of the methods for reducing NOx. (For example, see Japanese Patent Publication No. 57-54681.) However, this type of EGR type combustion device requires an exhaust gas recirculation passage, which has the problem of making the device complicated and expensive.

The present invention improves the above problems, has a simple configuration, does not require a recirculation passage, and reduces NOx emissions close to that of conventional EGR combustion devices.
Low N that provides a reduction effect.

The purpose is to provide an X combustion device.

(Means for Solving the Problems) In order to achieve the above object, the present invention uses a flame hole surface as the upper surface! IWi, a combustion device is formed by an upper combustion tube and a lower combustion tube in which two combustion tubes are arranged vertically and alternately, and a constriction part protruding outward is provided on both sides of the upper combustion tube, and the upper combustion tube is connected to the adjacent upper combustion tube. The structure is such that the passage between them is narrowed.

(Function) Since the passage between the throttle part of the upper combustion tube is narrowed, the combustion gas and secondary air in the lower combustion tube are mixed well, and the passage is accelerated by the throttle action. can pass through and leave the high temperature area of the flame quickly, NO
The occurrence of x can be reduced.

In addition, because the combustion tubes are arranged above and below, a portion of the exhaust gas from the lower combustion tube acts on the flame in the upper combustion tube, resulting in low oxygen combustion and lowering the flame temperature, resulting in a NOx reduction effect. Combined with the NOx reduction effect due to the throttling action described above, it is possible to achieve low NOx as a whole.

(Example) FIG. 1 is a sectional view of a main part showing an example of the present invention.
υ is the upper combustion tube, (2) is the lower combustion tube, and both have flame holes (3) and (4) on the upper surface, and multiple upper combustion tubes (1) and lower combustion tubes (2) are arranged vertically. They are alternately arranged in parallel to form a combustion device.

The upper combustion pipe (1) and the lower combustion tube (2J) are provided with pressure reducing walls (5) and (6) on both sides, respectively, which form supplementary flames. Parts of the pressure reducing wall (7) and (8) are provided by extending outward, and the reducing pressure wall (7) of the pressure reducing wall (5) of the upper combustion pipe (1) is connected to the pressure reducing wall (7) of the adjacent upper combustion pipe (1). The passage (9) between the passage (9) and the constriction part (7) provided in the lower combustion pipe (2) is narrowed, and the flow velocity of the combustion gas and secondary air in the lower combustion pipe (2) passing through this passage (9) is increased.

In order to narrow the passage (9), as shown in Fig. 2, the upper end of the pressure reducing wall αQ is bent outward to form a protruding 1-throttle portion συ, which is connected to the narrowed portion αυ of the adjacent pressure reducing wall GO. The passageway (12) between them may be narrowed. In addition to this, the third
As shown in the figure, the lower end of the pressure reducing wall 0 may be bent outward to form the constricted part a<, or as shown in FIG. Alternatively, another part may be attached to the side surface of the combustion tube or the pressure reducing wall to form the constriction part.

In short, it is only necessary to narrow the passage formed between the upper combustion tube and the adjacent upper combustion tube, and it is sufficient that the flow of combustion gas in the lower combustion tube is accelerated by the constricted portion.

With the above-mentioned configuration, the present invention improves the mixing of the combustion gas in the lower combustion pipe and the secondary air, and the throttle action of the throttle part (7) accelerates the flame through the passage (9), increasing the flame height. N because it passes through the temperature range quickly.

Reduces the generation of X.

In addition, a part of the exhaust gas from the lower combustion pipe (2) acts on the flame of the upper combustion pipe, resulting in low oxygen combustion and lowering the flame temperature.
Produces an Ox reduction effect.

(Effects of the Invention) As described above, according to the present invention, the combustion products passing through the passage are further accelerated by the throttling action of the restricting portion, and leave the high temperature region of the flame quickly, so that the generation of NOx can be reduced. Since the combustion tubes are arranged vertically and alternately, the exhaust gas from the lower combustion tube mixes with the flame from the upper combustion tube, resulting in low-oxygen combustion, which lowers the flame temperature and reduces the generation of NOx.
Overall, NOx can be significantly reduced with a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part showing one embodiment of the present invention, Figs. 2 and 3 are sectional views of the main part showing other embodiments of the throttle part of the pressure reducing wall, and Fig. 4 is a sectional view of the main part showing the throttle part of the pressure reducing wall. FIG. 3 is a sectional view of a main part showing an example in which a constricted portion is formed. (1), (2), (5), (7), (9), upper combustion pipe, lower combustion pipe, pressure reducing wall, throttle section, passage

Claims (1)

[Claims] A combustion device is formed by an upper combustion tube and a lower combustion tube in which a plurality of combustion tubes with the upper surface as a flame hole surface are arranged vertically and alternately in parallel, and a constriction part protruding outward is provided on both sides of the upper combustion tube. A low NOx combustion device characterized in that a passage between adjacent upper combustion pipes is narrowed.