WO2021027094A1 - Combustion apparatus for upper combustion chamber of sleeve kiln - Google Patents

Abstract

A combustion apparatus for an upper combustion chamber (1) of a sleeve kiln comprising an upper combustion chamber (1), a combustor (2), and a second coal gas nozzle (3). A furnace wall channel (101) is provided at the upper combustion chamber (1) and communicates the combustor (2) with the upper combustion chamber (1). The combustor (2) is installed on an outer wall of the upper combustion chamber (1). An outlet of the combustor (2) communicates with an inlet of the furnace wall channel (101). A space defined by the furnace wall channel (101) and the outlet of the combustor (2) forms a flue. The second coal gas nozzle (3) passes through a furnace wall of the upper combustion chamber (1), and communicates with the upper combustion chamber (1). The combustor (2) comprises a first coal gas nozzle (201) and a combustion air sleeve (202). A coal gas inlet (2011) is provided at one end of the first coal gas nozzle (201). The combustion air sleeve (202) is concentrically sleeved on an outer side of the first coal gas nozzle (201). The combustion air sleeve (202) is sleeved on the other end of the first coal gas nozzle (201) located away from the coal gas inlet (2011). An air inlet (2021) is provided at an end of the combustion air sleeve (202) near the coal gas inlet (2011). The combustion apparatus resolves the issues of serious damage to a refractory material caused by high temperature in the upper combustion chamber (1) of the sleeve kiln, low burnout rate, and high CO and NOx content in flue gas.

Description

Combustion device of combustion chamber on sleeve kiln Technical field

The invention relates to the technical field of combustion equipment, in particular to a combustion device of a combustion chamber on a sleeve kiln.

Background technique

With the development of lime production technology and the increasing requirements of various manufacturers for energy saving and cost reduction, the annular sleeve kiln is widely used because of its small footprint, high activity of the finished lime, high porosity, and low burnout rate. Lime production enterprises in the fields of metallurgy, chemicals and building materials.

The calcining process of the sleeve kiln determines that the upper combustion chamber of the sleeve kiln is under-oxygen combustion and the lower combustion chamber is over-oxygen combustion. The oxygen-deficient combustion in the upper combustion chamber can control the fuel burn rate in the upper combustion chamber by adjusting the air distribution rate, and then control the combustion temperature to not exceed 1250～1300℃ to protect the refractory materials; on the other hand, the incomplete combustion gas enters the material. After the layer, it is mixed with the mixed flue gas containing a large amount of air in the lower part, and is further burned in the material layer to form a countercurrent calcination zone.

In the actual engineering case, the mixed flue gas that has not been completely combusted, after being combusted in the countercurrent calcination zone, part of it enters the preheating zone, the other part enters the upper inner sleeve, and then is drawn to the exhaust system by the induced draft fan. There is still a large amount of flue gas CO exists and the concentration can reach 2000～3000mg/Nm ³ or even higher. In order to effectively reduce the emission of CO concentration, the effective way is to increase the fuel burnt degree in the upper combustion chamber. However, due to the use of oxygen-deficient combustion, as the air distribution coefficient increases, the temperature of the combustion chamber will inevitably increase, which will cause serious damage to the refractory materials. The damage, greatly shortening the service life of refractory materials.

At the same time, although low-nitrogen combustion has been adopted in the combustion process of the annular sleeve kiln, including the under-oxygen combustion in the upper combustion chamber and the over-oxygen combustion in the lower combustion chamber, it belongs to the category of air classification and gas classification. The flue gas is injected to form a flue gas circulation, which reduces the combustion temperature and oxygen content of the lower combustion chamber, which belongs to the flue gas circulation low-nitrogen combustion technology. However, with the further improvement of environmental protection requirements, sleeve kiln flue gas emissions are facing more stringent requirements. Through the process optimization of the burner, further reducing the emission of nitrogen oxides is of great significance.

Summary of the invention

In order to solve the above technical problems, the present invention provides a combustion device for the upper combustion chamber of the sleeve kiln, which solves the problem that the high temperature of the upper combustion chamber of the sleeve kiln will cause serious damage to the refractory material, low burning rate, and the content of CO and NO _{x in the} flue gas. On the high side.

The technical scheme of the present invention is as follows:

A combustion device for an upper combustion chamber of a sleeve kiln, which is characterized in that it comprises an upper combustion chamber, a burner and a plurality of second gas nozzles, the upper combustion chamber is provided with a furnace wall channel, and the burner is installed in the The outer wall of the upper combustion chamber, the outlet of the burner communicates with the furnace wall channel and forms a flue; the second gas nozzle passes through the furnace wall of the upper combustion chamber and communicates with the upper combustion chamber; The burner includes a first gas nozzle and a combustion air sleeve, one end of the first gas nozzle is provided with a gas inlet, the combustion air sleeve is sleeved outside the first gas nozzle, and the combustion air sleeve Located at the end of the first gas nozzle away from the gas inlet, the combustion-supporting air sleeve is provided with an air inlet at one end close to the gas inlet.

The combination of the burner and the second gas nozzle changes the centralized combustion of the fuel in the combustion chamber of the original sleeve kiln to the staged combustion of fuel. By controlling the ratio of air and gas, the burner produces a first-stage combustion, which is complete combustion. Then, the mixed flue gas in the flue is injected into the upper combustion chamber and the secondary gas passed through the second gas nozzle produces a second-stage combustion, because Part of the oxygen is consumed during the primary combustion, so the mixed combustion of mixed flue gas and secondary gas is incomplete combustion. Because the secondary gas can significantly reduce the temperature of the refractory material in the upper combustion chamber, due to the decrease in the temperature of the refractory material, it is possible to appropriately increase the air ratio coefficient of the upper combustion chamber and increase the burning rate within the temperature range that the refractory material can withstand. Reduce CO concentration due to incomplete combustion. In addition, passing secondary gas can form a strong reducing atmosphere and reduce NO _x production.

Preferably, the second gas nozzle is evenly arranged along the circumferential direction of the central axis of the burner.

The beneficial effect of adopting this step is to further ensure the effective reduction of the refractory temperature of the upper combustion chamber.

Preferably, the end of the combustion-supporting air passage is provided with a swirling sheet, the air outlet end of the combustion-supporting air sleeve is provided with a swirling sheet, and the air outlet end of the first gas nozzle is connected with a diverging premixing tube, The pre-mixing shrinking tube is located in the air outlet end of the combustion-supporting air sleeve, and the expanded diameter section of the pre-mixing shrinking tube has circumferentially spaced vents.

The beneficial effects of adopting this step are: the swirl vane and the premixing shrink tube ensure that the air and the primary gas can be better mixed, and the sufficiency of the primary combustion is ensured.

Preferably, the burner further includes an observation tube which is sleeved concentrically in the first gas nozzle.

The beneficial effect of adopting this step is that the observation tube facilitates the observation of the fuel combustion in the upper combustion chamber.

Preferably, it further comprises a flange which is sleeved on the outer side of the combustion air sleeve and connected with the outer wall of the upper combustion chamber.

Preferably, a plurality of mounting holes for installing the second gas nozzle are evenly distributed on the concentric circumference of the flange, and a plurality of through holes matching the mounting holes are provided around the furnace wall channel.

The beneficial effect of adopting this step is that the installation parts are reduced, and the burner and multiple second gas nozzles can be installed in the upper combustion chamber only through the flange, which is convenient for installation and disassembly.

The beneficial effects of the present invention:

1. The present invention provides a combustion device for the upper combustion chamber of a sleeve kiln, which mainly includes a burner and a plurality of second gas nozzles, which changes the centralized combustion of fuel in the upper combustion chamber of the original sleeve kiln to a staged fuel combustion . Passing secondary gas into the second gas nozzle can significantly reduce the temperature of the refractory material in the upper combustion chamber. Therefore, under the condition of ensuring the normal use temperature of the refractory material, the air distribution coefficient can be appropriately increased, thereby increasing the burning rate and reducing the upper combustion chamber. The concentration of CO. In addition, the secondary gas passed through the second gas nozzle can form a strong reducing atmosphere and reduce the production of NO _x .

2. In the present invention, the burner includes a first gas nozzle and a combustion-supporting air sleeve. The gas outlet end of the combustion-supporting air sleeve is provided with a swirling fin. The gas outlet end of the first gas nozzle is provided with a premixing tube, and the premixing tube is located at The air outlet end of the combustion-supporting air sleeve improves the mixing effect of primary gas and air and ensures the adequacy of combustion.

3 In the present invention, an observation tube is concentrically sleeved in the first gas sleeve, and the observation tube is convenient to observe the fuel combustion in the upper combustion chamber.

Description of the drawings

Figure 1 is a schematic diagram of the structure of a combustion device of a combustion chamber on a sleeve kiln according to an embodiment of the present invention;

Figure 2 is a schematic diagram of the structure of the burner in an embodiment of the present invention

among them:

1- upper combustion chamber; 2- burner; 3- second gas nozzle; 4- flange;

101- Furnace wall channel;

201-the first gas nozzle; 202-combustion-supporting air casing; 203-observation tube; 204-swirl vane; 205-premixed shrink tube;

2011-gas import; 2021-air import.

detailed description

The embodiments of the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and therefore are only used as examples, and cannot be used to limit the protection scope of the present invention.

It should be noted that, unless otherwise specified, the technical or scientific terms used in this application shall have the usual meaning understood by those skilled in the art to which the present invention belongs.

In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inner", "outer", "front", "rear", "circumferential", and "central axis" The orientation or positional relationship of other indications is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the pointed device or element must have a specific orientation and The azimuth structure and operation cannot be understood as a limitation of the present invention. In addition, in the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , Or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present invention can be understood according to specific circumstances.

Referring to Figure 1, the present invention provides a combustion device for the upper combustion chamber of a sleeve kiln, which includes an upper combustion chamber 1, a burner 2 and a second gas nozzle 3. The upper combustion chamber 1 is provided with a furnace wall channel 101 for The burner 2 communicates with the upper combustion chamber 1, wherein the burner 2 is installed on the outer wall of the upper combustion chamber 1, and the outlet of the burner 2 communicates with the inlet of the furnace wall channel 101, and the furnace wall channel 101 and the burner 2 outlet constitute A flue is formed in the space of the burner 2, and the primary combustion of the burner 2 is mainly carried out in the flue; the second gas nozzle 3 passes through the furnace wall of the upper combustion chamber 1 and communicates with the upper combustion chamber 1. Normally, the first The outlet of the second gas nozzle 3 is flush with the outlet of the furnace wall channel 101, which ensures that the second gas nozzle 3 is wrapped in the refractory material and prevents the high temperature in the upper combustion chamber 1 from damaging the second gas nozzle 3. The service life of the second gas nozzle 3 is prolonged, and the secondary gas introduced by the second gas nozzle 3 is mixed with the flue gas produced by the first-stage combustion to produce incomplete combustion.

When the sleeve kiln is running, the second gas nozzle 3 continuously feeds secondary gas into the upper combustion chamber 1. The secondary gas can significantly reduce the temperature of the refractory material in the upper combustion chamber 1. Therefore, under the condition of ensuring the normal use temperature of the refractory material , The air distribution coefficient can be appropriately increased, thereby increasing the burning rate, while reducing the CO concentration in the upper combustion chamber 1. In addition, the incoming secondary gas can also form a strong reducing atmosphere, reducing NO _x production.

Referring to Figure 2, the burner 2 includes a first gas nozzle 201 and a combustion air sleeve 202,

Among them, one end of the first gas nozzle 201 is provided with a gas inlet 2011, a combustion air sleeve 202 is sleeved concentrically on the outside of the first gas nozzle 201, and a combustion air sleeve 202 is sleeved on the first gas nozzle 201 away from the gas inlet At the other end of 2011, an air inlet 2012 is provided at one end of the combustion-supporting air sleeve 202 close to the gas inlet 2011. The outlet end of the first gas nozzle 201 is located in the outlet end of the combustion-supporting air sleeve 202, and the other end of the first gas nozzle 201 is outside the combustion-supporting air sleeve 202. 202 long.

In an embodiment, in order to further ensure that the temperature of the secondary gas to the refractory material is significantly reduced, there are multiple second gas nozzles 3, and the multiple second gas nozzles 3 are along the burner 2 (or furnace wall channel 101). The circumferential direction of the central axis is evenly arranged on the upper combustion chamber 1. Generally, 4-8 are better. The specific number and location of the second gas nozzle 3 need to be set according to the combustion process requirements of the sleeve kiln.

In an embodiment, in order to enhance the mixing of air and primary gas, the gas outlet end of the combustion-supporting air sleeve 202 is provided with a swirl fin 204, and the gas outlet end of the first gas nozzle 201 is connected to a divergent premixing shrinking tube 205, and the premixing The shrinking tube 205 is located in the combustion-supporting air sleeve 202, and the expanded diameter section of the premixing shrinking tube 205 has vent holes distributed at intervals in the circumferential direction. The structure of the pre-mixing shrink tube 205 is as shown in FIG. 2. A cavity is formed between the air outlet end of the combustion-supporting air sleeve 202 and the air outlet end of the first gas nozzle 201, and the premixing shrink tube 205 is arranged in the cavity. The angle of the swirl plate 204 can be set according to the specific requirements of the sleeve kiln combustion process, and generally can be set to 30-45°. The swirling fin 204 makes the air in the combustion-supporting air sleeve produce a swirling flow at the outlet end, and can wrap the primary gas for mixing. The expanded diameter section of the premixing shrinking tube 205 reduces the cross-sectional area of the combustion-supporting air channel and can speed up the air. Or the negative pressure entrainment can be formed by the high-speed air flow from the primary gas. Part of the air passes through the through hole of the expanded diameter section of the premixing tube 205 to produce negative pressure entrainment. The gas is first mixed or the gas generates negative pressure to suck in some air through the through hole. Mixing, and then mixing with the speed-up air, this is more conducive to full combustion.

In an embodiment, the burner 2 further includes an observation tube 203, and the observation tube 203 is sleeved concentrically in the first gas nozzle 201. Observe the combustion situation in the upper combustion chamber through the front end of the observation tube 203.

In an embodiment, the burner 2 is fixedly connected to the upper combustion chamber 1 through a flange 4, which is sleeved on the outside of the air outlet end of the combustion-supporting air sleeve 202, and is connected to the upper combustion chamber by other conventional methods such as connectors. 1 is connected, the outlet of the burner 2 is matched with the inlet of the furnace wall channel 101.

In an embodiment, the second gas nozzle 3 is also connected to the upper combustion chamber through a flange 4. The specific structure of the flange 4 is the central circular hole used to sleeve the combustion-supporting air sleeve 202. A plurality of mounting holes for installing the second gas nozzle 3 are opened around the concentric circumference of the, and the positions of the mounting holes match the positions of the through holes opened on the outer periphery of the furnace wall channel 101.

Regarding the position and quantity of the installation holes and the through holes, and the position and quantity of the second gas nozzles, they are all set according to the specific sleeve kiln combustion process requirements; burner 2, second gas nozzle 3 and burner The installation of components such as the first gas nozzle 201, the combustion-supporting air sleeve 202, the observation tube 203, the swirl plate 204, and the premixing shrink tube 205 in 2 are all conventional means in the technical field, and therefore will not be described in detail.

The present invention is fuel staged combustion. By controlling the ratio of gas and air, the complete combustion produced by the burner 2 is one-stage combustion, and the first-stage combustion is mainly carried out in the flue formed by the outlet of the burner 2 and the furnace wall channel 101; The incomplete combustion produced by the secondary gas nozzle 3 is secondary combustion, and the secondary combustion zone is located outside the primary combustion zone.

The combustion process of a certain embodiment:

The first gas nozzle 201 is connected to the gas conveying equipment through the gas inlet 2011, and the combustion-supporting air sleeve 202 is connected to the air pipeline through the air inlet 2021. When air and gas are respectively passed into the combustor 2, the air outlet end of the combustion-supporting air sleeve 202 is provided with a swirling fin 204, and the air swirls at the outlet end of the combustion-supporting air sleeve 202 and wraps the gas to rotate and mix; and combustion; A recirculation zone is formed at the exit of the burner 2, and the hot smoke generated can be drawn to the exit of the burner to participate in combustion again.

The gas outlet end of the first gas nozzle 201 is connected with a divergent premixing shrinking tube 205. The premixing shrinking tube 205 reduces the cross-sectional area of the combustion-supporting air sleeve 202, so that the air speed is increased, which is more conducive to the mixing of air and gas. Since the expansion section of the premixing shrink tube 205 is provided with a through hole, part of the air passes through the through hole of the premixing shrink tube 205 to produce negative pressure and entrains the gas first to mix or the gas produces negative pressure to suck in part of the air through the through hole to mix first, and then It is then mixed with the speed-up air to make the mixing effect better and further ensure full combustion.

The second coal gas nozzle 3 is connected with the coal gas conveying equipment. During the combustion process of the upper combustion chamber 1, coal gas is continuously introduced for secondary combustion, and the coal gas and the hot flue gas of the primary combustion are incompletely combusted. Since the second gas nozzle 3 is fed with gas, the temperature of the refractory material in the upper combustion chamber 1 can be significantly reduced, so under the premise of ensuring that the refractory material is at the normal use temperature, the air distribution coefficient can be appropriately increased, the burning rate can be increased, and the burning rate can be reduced. The concentration of CO.

For example: the temperature of the upper combustion chamber is generally required to be controlled below 1250°C. For traditional burners, the air distribution coefficient can only be 0.5 and exceeds 0.5. The temperature of the upper combustion chamber exceeds 1250°C. When the air distribution coefficient is 0.55, the temperature of the upper combustion chamber reaches 1280～1300℃; When the air distribution coefficient is 0.6, the temperature of the combustion chamber reaches about 1300～1350℃, and the refractory material in the sleeve kiln is overheated.

By adopting the combined structure of the burner and the secondary gas nozzle of the present invention, the air distribution coefficient can be increased to 0.6, and the temperature can be controlled below 1250°C.

In addition, the ignition of the upper combustion chamber 1 mainly relies on the combustion of the lower combustion chamber to make the temperature of the furnace and the upper combustion chamber reach the ignition temperature of the fuel. At this time, gas and air are injected to achieve ignition and combustion.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: It is still possible to modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention range.

Claims (6)

1. A combustion device for an upper combustion chamber of a sleeve kiln, which is characterized in that it comprises an upper combustion chamber, a burner and a plurality of second gas nozzles, the upper combustion chamber is provided with a furnace wall channel, and the burner is installed in the The outer wall of the upper combustion chamber, the outlet of the burner communicates with the furnace wall channel and forms a flue; the second gas nozzle passes through the furnace wall of the upper combustion chamber and communicates with the upper combustion chamber; The device includes a first gas nozzle and a combustion air sleeve, one end of the first gas nozzle is provided with a gas inlet, the combustion air sleeve is sleeved outside the first gas nozzle, and the combustion air sleeve is located The end of the first gas nozzle far away from the gas inlet, and the end of the combustion-supporting air sleeve close to the gas inlet is provided with an air inlet.
2. The combustion device of the upper combustion chamber of the sleeve kiln according to claim 1, wherein the second gas nozzle is evenly arranged along the circumferential direction of the central axis of the burner.
3. The combustion device of the upper combustion chamber of the sleeve kiln according to claim 1, wherein the air outlet end of the combustion-supporting air channel is provided with a swirling fin, and the air outlet end of the first gas nozzle is connected to a gradually expanding pre A mixing tube, the pre-mixing tube is located in the air outlet end of the combustion-supporting air sleeve, and the expanded diameter section of the pre-mixing tube has vent holes distributed at intervals in the circumferential direction.
4. The combustion device of the upper combustion chamber of the sleeve kiln according to claim 1, wherein the burner further comprises an observation tube, and the observation tube is sleeved concentrically in the first gas nozzle.
5. The combustion device of the upper combustion chamber of the sleeve kiln according to any one of claims 1 to 4, further comprising a flange, the flange is sleeved on the outside of the combustion air sleeve and is in contact with the The outer wall of the upper combustion chamber is connected.
6. The combustion device of the upper combustion chamber of the sleeve kiln according to claim 5, wherein a plurality of installation holes for installing the second gas nozzle are evenly distributed on the concentric circumference of the flange, and the furnace wall A plurality of through holes matched with the mounting holes are arranged around the channel.

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