JPH02106607A - Radiant gas burner - Google Patents

Abstract

PURPOSE:To reduce thermal NOX through slow combustion by forming a secondary fuel-distributing chamber in the fixing means and by providing a plurality of secondary fuel nozzles extending from the secondary fuel-distributing chamber and along the outer side of the main body of a gas burner and having nozzle openings near the ejection openings of the gas burner in a setup to diffuse the secondary fuel as it is ejected from the nozzle openings. CONSTITUTION:When primary fuel A is blown into an outer end opening 6b from a primary fuel nozzle 16, primary air B is drawn in by the ejector action at a venturi tube section 6. The primary fuel A and the primary air B are preliminarily mixed to form a fuel-air premix C, which is ejected into the furnace 10 through ejection openings 8 in a primary gas nozzle 5 to form a stabilized flat flame. The air drawn in amounts to 80 to 90% of the total of the air required for the primary and the secondary fuel. The combustion is thinly supplied with fuel so that the formation of thermal NOX is suppressed. The secondary fuel D in a secondary fuel-distributing chamber 13 flows through secondary fuel nozzles 20 to the openings 22 of the respective secondary gas tips 21 and is diffused into the periphery of the primary gas nozzle 5. The secondary fuel D is ejected in a manner of diffusion without being premixed with air and made to burn slowly. The combustion is slow and stabilized, free from peaks in temperature, and results in the reduction of thermal NOX.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a diffusion type radiant gas burner that can be used in an ethylene cracking furnace, an ethylene dichloride cracking furnace, etc., and can perform stable combustion at a low air ratio.

Conventional technology The gas burners used in ethylene cracking furnaces and ethylene dichloride cracking furnaces have traditionally been used for the purpose of uniformly heating the heating tubes.
A radiant gas burner that forms a flat flame is used. This radiant gas burner is generally of a natural ventilation type and is configured as a premixed gas burner using an ejector. That is, as shown in FIG.
The gas nozzle portion 3 is disposed inside and outside the furnace through a through hole 32 formed in the furnace wall 31, and is fixed to the outside surface of the furnace wall via a member 33.
5 and a venturi tube portion 37 protruding outside the furnace 36. The gas nozzle portion 35 has a closed end 35a, and a plurality of slit-like jets 038 are formed at equal intervals around the entire circumference of the pipe wall near the closed end. A gas ejection nozzle 40 attached to the free end of the fuel gas supply pipe 39 is arranged opposite to the opening 37a of the venturi pipe section 37 outside the furnace 36.

According to such a conventional configuration, by ejecting the fuel gas G from the gas ejection nozzle 40 toward the opening 37a,
An ejector is generated in the venturi pipe section 37 to draw in primary air H from the outside, and the fuel gas G and primary air H are mixed while flowing to form a premixture I. The premixture I that has entered the gas nozzle section 35 is ejected from the jet port 38 to form a flat flame, which is burned along the inner surface of the furnace wall 31. ) gives heat to At that time, secondary air J is supplied through a through hole 41 formed in the member 33 during the installation.

Problems to be Solved by the Invention According to the conventional system as described above, since a premixture I of fuel gas G and primary air H is supplied and combusted, this premixture I is mixed with secondary air J. The mixture is good, combustion occurs quickly, and combustion is completed quickly, resulting in stable combustion. However, on the other hand, there is a problem that thermal NOx cannot be generated. In recent years, both domestically and internationally, NO8 value regulations have begun to be tightened not only for new furnaces but also for existing furnaces, and countermeasures for existing burners have become necessary, so it is important that NOx is easily generated. That's a problem.

The purpose of the present invention is to provide a radiant gas burner that can be installed not only in new furnaces but also in existing furnaces with a slight modification, and that enables a significant reduction in NO8 without reducing combustion efficiency. At the point.

Means for Solving the Problems In order to achieve the above objects, the radiant gas burner of the present invention is arranged inside and outside the furnace through a through hole formed in the furnace wall, and is fixed to the outside surface of the furnace wall through a member. A radiant gas burner, which has a gas burner body whose inner end is closed, has a plurality of jet ports formed around the entire circumference of the tube wall near the closed end, and has a primary fuel nozzle facing the frontage of the outer end of the gas burner body. At the same time, the ejector action caused by the injection of primary fuel is configured to draw in a smaller amount of air than the amount of air required for the total fuel, and the mounting forms a secondary fuel distribution chamber on the member side, and the secondary fuel distribution chamber is A plurality of secondary fuel nozzles communicating with a secondary fuel distribution chamber open through the outside of the gas burner body near the spout.

According to the configuration of the present invention, the premixture mixed within the gas burner main body is ejected from the ejection port into the furnace, forming a stable flat flame and combusting. At that time, since the amount of air is smaller than the amount of air required for all the fuel, the premixture ensures a stable flame while burning lean fuel, resulting in thermal NOx
The occurrence of is suppressed. On the other hand, the secondary fuel (raw gas) flowing from the secondary fuel distribution chamber into the secondary fuel nozzle is diffused and ejected through the opening and is combusted, but at this time there is a lack of air near the gas ejection part. As a result, a combustion delay occurs, and the gas becomes over-rich, causing slow combustion and reducing thermal N08.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

Reference numeral 1 denotes a gas burner body, which is disposed inside and outside the furnace through a through hole 3 formed in a furnace wall 2, and is fixed to the outer surface of the furnace wall 2 via a member 4. This gas burner body 1 is
It is constructed by integrating a gas nozzle portion 5 protruding into the furnace interior 10 and a venturi tube portion 6 protruding to the outside of the furnace 11 using a screw connection 7 or the like. The gas nozzle portion 5 has a closed end 5aL, and a plurality of slit-shaped jet ports 8 are formed at equal intervals around the entire circumference of the pipe wall near the closed end 5aL.

The mounting member 4 is a base plate portion 1 fixed to the furnace wall 2.
2, an intermediate member 14 that forms an annular secondary fuel distribution chamber 13 by being applied to this base plate portion 12, and a pressing member 15 that is applied to this intermediate member 14,
A primary fuel nozzle 16, which fixes the gas burner main body 1 through the large-diameter portion 6a of the venturi pipe portion 6 and is disposed opposite the outer end opening 6b of the venturi pipe portion 6, communicates with a fuel pipe 17. A secondary fuel pipe 18 branched from the fuel pipe 17 communicates with the secondary fuel distribution chamber 13. A plurality of secondary fuel nozzles 2 connected to the secondary fuel distribution chamber 13 by screwing 19 to the base plate portion 12, etc.
0 are provided, and these secondary fuel nozzles 20 are disposed through the outside of the gas burner body 1 within the through hole 3. A secondary gas tip 21 located close to the ejection port 8 is attached to the tip of each secondary fuel nozzle 20, and a plurality of openings 22 are formed in the secondary gas tip 21.

In the above-mentioned radiant gas burner, when primary fuel A is blown from the primary fuel nozzle 16 toward the outer end opening 6b, the primary air B is sucked by the ejector action in the venturi pipe section 6. The primary fuel A and the primary air B are premixed and ejected as a premixed mixture C from the jet port 8 of the primary gas nozzle portion 5 into the furnace interior 10, forming a stable flat flame and combusting. At this time, 80 to 90% of the amount of air required for the primary and secondary fuel is sucked in by the ejector action. Therefore, the premixture C ensures fuel-lean combustion while ensuring a stable flame, and the generation of thermal NO is suppressed. A portion of the fuel being pumped through the fuel pipe 17 is branched into the secondary fuel pipe 18 to become secondary fuel, and enters the secondary fuel distribution chamber 13. The secondary fuel in the secondary fuel distribution chamber 13 flows through each secondary fuel nozzle 20 and is diffused through the opening 22 of the secondary gas tip 21 to the periphery of the primary gas nozzle section 5 or to the inner surface of the burner tile. At this time, the secondary fuel is not premixed with air and is combusted as a diffused jet.

At that time, the secondary fuel will have a combustion delay due to lack of air near the gas ejection part, and the gas will become over-rich.
The premixture C burns slowly along the gas flow.

In this way, diffusion combustion is slow and stable combustion, and no temperature peak occurs, so it also reduces thermal NOx.

The distribution ratio between primary fuel A and secondary fuel is 5Q: 50-60
:40. In terms of reducing N08, it has been experimentally proven that primary fuel A and secondary fuel B are more effective, but in practice, a ratio of 50:50 is the maximum, and if this is exceeded, stable combustion will be lacking.

The above-described secondary fuel nozzle 20 can be installed in all burners of this type by modifying a part of the combustion port of the existing burner, that is, by modifying the member 4 and the like.

Effects of the Invention According to the present invention having the above configuration, the premixed mixture in the gas burner main body can be injected into the furnace from the jet nozzle to form a stable flat flame and be combusted, and at that time, the air Since the amount of air is smaller than the amount of air required for all the fuel, the premixture can ensure a stable flame while burning the fuel lean.
Generation of thermal NO8 can be suppressed. In addition, the secondary fuel (raw gas) that flows through the secondary fuel nozzle and is diffused and ejected through the opening has a combustion delay due to the lack of air near the gas ejection part, resulting in gas over-concentration and slow combustion. Therefore, thermal NO8 can be reduced as well. Due to these factors, a bias effect can be expected, and the generation of thermal NOx can be significantly reduced. The radiant gas burner of the present invention can be installed not only in new furnaces but also in existing furnaces with a slight modification.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 show an embodiment of the present invention, Fig. 1 is a longitudinal sectional view, Fig. 2 is a partial longitudinal sectional view of the secondary fuel part, and Fig. 3 is a longitudinal sectional view of a conventional example. It is. DESCRIPTION OF SYMBOLS 1... Gas burner body, 2... Furnace wall, 3... Through hole, 4... Mounting member, 5... Gas nozzle part, 5a
...Closure, 6...Venturi pipe section, 6b...Outer end opening, 8...Ejection port, 12...Base plate section, 1
3...Secondary fuel distribution chamber, 14...Intermediate member, 16.
...Primary fuel nozzle, 17... Fuel pipe, 18... Secondary fuel pipe, 20... Secondary fuel nozzle, 21... Secondary gas tip, 22... Opening, A... Primary fuel, C.
... Premixture, D... Secondary fuel. Agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. A radiant gas burner that is installed inside and outside of the furnace through a through hole formed in the furnace wall and fixed to the outside of the furnace wall via a mounting member, near the closed end of the gas burner main body whose inner end is closed. A plurality of jet ports are formed around the entire circumference of the pipe wall, and a primary fuel nozzle is arranged opposite to the opening at the outer end of the gas burner body, and an ejector action by blowing the primary fuel reduces the amount of air required for the total fuel. A secondary fuel distribution chamber is formed on the mounting member side, and a plurality of secondary fuel nozzles communicating with the secondary fuel distribution chamber are connected to the gas burner body through the outside of the gas burner body. A radiant gas burner characterized by opening near the spout.