CN218972677U - Tail gas incinerator - Google Patents

Abstract

The utility model relates to a tail gas incineration device, which aims to reduce thermal nitrogen oxides generated in the initial stage of incineration in the tail gas incineration device, wherein the tail gas incineration device comprises a hearth; a cooling device having a cooling channel; the cooling channel is communicated with the bottom of the hearth, and the tail gas enters the hearth after being cooled by the cooling channel. The tail gas incineration device can form lower flame center temperature in the incineration process, so that thermal nitrogen oxides generated in the initial stage of the incineration are reduced.

Description

Tail gas incinerator

Technical Field

The present utility model relates to a tail gas incinerator.

Background

In the process of melting and incinerating organic wastes, H-containing substances are generated ₂ And combustible tail gases of CO, which are required to be sent to an incinerator for incineration treatment. The incineration process is also accompanied by the production of nitrogen oxides. These nitrogen oxides can be classified into thermal type, transient type and fuel type according to the cause of the generation. Wherein the thermal nitrogen oxides are generated by the reaction of nitrogen and oxygen at a temperature higher than 1500 ℃, and the content of the thermal nitrogen oxides increases with the temperature. The thermal nitrogen oxides can cause the pressure of subsequent flue gas purification, and the reaction for forming the nitrogen oxides can compete for H ₂ And oxygen required for CO combustion.

In order to avoid the production of thermal nitrogen oxides, the temperature in the furnace needs to be controlled. The first way is to increase the air intake to control the furnace temperature, which increases the throughput of the subsequent tail gas; in the second mode, a hearth is constructed by using water cooling walls, and partial heat of the hearth is taken away in a water cooling heat exchange mode to realize temperature control. However, the temperature of the tail gas generated by melting the organic waste is already up to 1200-1400 ℃, so that the temperature in the flame center of the hearth is high, partial thermal nitrogen oxides are already formed in the initial stage of burning, and the mode of increasing the air inlet quantity and heat exchange of the furnace wall cannot effectively reduce the nitrogen oxides generated in the initial stage of burning.

Disclosure of Invention

The main purpose of the utility model is to reduce the thermal nitrogen oxides generated in the initial stage of burning in the tail gas burning device.

In order to achieve the above object, a first aspect of the present utility model provides an exhaust gas incineration device, including a furnace, further including:

a cooling device provided with a cooling channel,

the cooling channel is communicated with the bottom of the hearth, and the tail gas enters the hearth after being cooled by the cooling channel.

In some embodiments of the first aspect of the present utility model, the cooling device is a first ash cooling hopper, the first ash cooling hopper is connected to the bottom of the furnace chamber, and a tail gas inlet is formed on a side wall of the first ash cooling hopper.

In some embodiments of the first aspect of the utility model, the exhaust gas treatment device further comprises an inlet channel connected obliquely downward to the exhaust gas inlet.

In some embodiments of the first aspect of the utility model, the inlet channel is disposed opposite at least one cooling surface within the first cold ash bucket.

In some embodiments of the first aspect of the present utility model, the cooling system further comprises an inlet channel connected to the cooling channel, wherein the inlet channel is formed by a water wall.

In some embodiments of the first aspect of the present utility model, the vertical type first flue and the vertical type second flue are included, the top of the first flue is connected with the furnace, the bottom of the first flue is connected with the bottom of the second flue, the flue gas of the furnace is discharged through the first flue and the second flue in sequence, the bottoms of the first flue and the second flue are jointly provided with the second ash cooling hopper, and the furnace, the first flue and the second flue are all composed of water cooling walls.

In some embodiments of the first aspect of the present utility model, bottoms of the first flue and the second flue have a conical ash outlet for collecting fly ash, and bottoms of the ash outlets are connected with the second ash cooling hopper.

In some embodiments of the first aspect of the utility model, SNCR lances are disposed in the first flue.

In some embodiments of the first aspect of the present utility model, the water cooling wall further comprises a steam drum and a water circulation pipeline, wherein the water cooling wall is communicated with the steam drum through the water circulation pipeline, and the water circulation pipeline forms a frame structure for supporting outside the hearth, the first flue and the second flue.

In some embodiments of the first aspect of the present utility model, an air inlet mechanism is disposed on the furnace, an outlet of the second flue gas channel is connected with a flue gas purifying device, the flue gas purifying device is connected with the air inlet mechanism through the flue gas channel, and clean flue gas purified by the flue gas purifying device is sent into the air inlet mechanism through the flue gas channel.

The tail gas incineration device can form lower flame center temperature in the incineration process, so that thermal nitrogen oxides generated in the initial stage of the incineration are reduced.

Drawings

Fig. 1 is a schematic view of a structure of an incinerator.

In the figure: 1-inlet channel, 2-furnace, 3-steam drum, 4-emergency discharge chimney, 6-primary air bellows, 7-first flue, 8-secondary air bellows, 9-second ash cooling hopper, 10-second flue, 11-ash outlet, 13-burner, 14-SNCR spray pipe, 16-first ash cooling hopper, 17-cooling surface, 18-first water-cooled wall, 19-second water-cooled wall, 20-downcomer, 21-riser, 22-steam-water separation pipe, 23-primary air inlet.

Detailed Description

In order to solve the problem that flame center temperature is too high when tail gas burns, forms thermal type nitrogen oxide at the initial stage of burning, this application provides a tail gas burns device, aims at being able to reduce the center temperature of flame at the burning in-process, and it mainly includes furnace, still includes cooling device, has cooling channel in the cooling device, and tail gas receives the cooling in cooling channel, and cooling channel and furnace bottom communicate, and tail gas gets into furnace by the bottom after cooling channel's cooling.

Compared with the method of directly introducing the tail gas generated by the melting furnace into the incinerator for burning by utilizing the heat of the tail gas, the burning device of the application enables the tail gas to be cooled to a certain extent in advance before entering the hearth. The temperature of the tail gas influences the central temperature of flame during combustion, and the central temperature of flame is reduced along with the reduction of the temperature of the tail gas, so that the thermal nitrogen oxides generated at the initial stage of combustion can be reduced. Therefore, no matter how much the temperature of the tail gas is reduced before entering the hearth, the thermal nitrogen oxides generated in the initial stage of burning can be relatively reduced. Compared with the method that the hearth temperature and the outlet temperature are focused to reduce the nitrogen oxides generated in the middle section and the tail section of the incineration process in the prior art, the method is focused on the nitrogen oxides generated in the initial process of the incineration, and therefore the method can be used as a supplement to the prior nitrogen oxide reduction method.

A preferred way of cooling the flue gases to be burnt in the furnace is to use a cold ash bucket. The first ash cooling hopper is connected to the bottom of the hearth, and a tail gas inlet is formed in the side wall of the first ash cooling hopper. The first ash cooling hopper is used as a cooling device, so that the ash collecting function can be achieved, and the benefit is self-evident. Further, an inlet channel may be connected at the tail gas inlet of the first cold ash bucket and connected obliquely downwards to the tail gas inlet. The advantage of doing so lies in that by the entering passageway guide tail gas in the first cold ash bucket of slope decurrent direction to let the tail gas form a decurrent motion process that goes up again in first cold ash bucket, in order to increase the time of tail gas in cold ash bucket, improve the cooling effect. Ash carried in the exhaust gas, on the other hand, can slide down the downward inlet channel into the first ash cooling hopper, preventing ash build-up in the inlet channel from clogging. The inlet channel can be arranged opposite to at least one cooling surface in the first ash cooling hopper, and after the tail gas enters the first ash cooling hopper, the tail gas is blown onto the opposite cooling surface for heat exchange and cooling, and ash slag in the tail gas slides along the cooling surface. To further increase the cooling effect, the inlet channel may also be constituted by a water cooled wall.

The tail gas incinerator further comprises a vertical first flue and a vertical second flue. The top of first flue with furnace be connected, the bottom of first flue is connected with the bottom of second flue, and furnace's flue gas is discharged through first flue and second flue in proper order, and the bottom of first flue and second flue is provided with the cold ash bucket of second jointly, furnace, first flue and second flue constitute by the water-cooled wall. The adoption of the water-cooled wall as the furnace wall of the furnace is an improvement relative to the existing adiabatic furnace. The wall body of the adiabatic furnace is generally constructed by refractory bricks, the wall thickness is generally more than 200mm, and the center temperature and the outlet temperature of the furnace are controlled by introducing a large amount of cold air into the adiabatic furnace, so that the adiabatic furnace has larger volume, higher manufacturing cost and more occupied area. Compared with an adiabatic hearth, the hearth structure of the furnace has the following advantages: a. the temperature of the hearth can be directly regulated by the water-cooled wall, no additional cooling air is needed, and the diameter of the hearth can be reduced by 12-15%; b. the thickness of the refractory material layer of the lining can be reduced to 50mm, the temperature of the refractory material under the cooling action of the water-cooled wall is lower, the thermal vibration is smaller, the refractory material is not easy to damage, and the replacement frequency is reduced; c. the thickness of the refractory material layer is reduced, the temperature of the hearth rises faster, the starting time is shorter, the consumed combustion-supporting gas amount is less, and the operation cost is lower. When the flue gas is burnt in the hearth, a part of heat is taken away by the water cooling wall of the hearth so as to adjust the temperature of the hearth and the outlet of the hearth, and the first flue and the second flue take away the residual heat of the flue gas generated by partial burning so as to reduce the temperature of the flue gas. The water cooling wall can be communicated with the steam drum through a water circulation pipeline, so that the waste heat can be utilized to produce steam, and the produced steam can be further used for heating other process sections.

The bottoms of the first flue and the second flue are provided with conical ash outlets for collecting fly ash, and the bottoms of the ash outlets are connected with the second ash cooling hopper. In the process of passing through the first flue and the second flue, the carried ash is further cooled and settled, and the ash is guided by an ash outlet and falls into a second ash cooling hopper to be further collected.

An SNCR lance is disposed in the first flue. The flue gas generated by incineration firstly enters the first flue, the water-cooled wall of the first flue can cool the flue gas, ammonia water or urea and the like sprayed by the SNCR spray gun are contacted with tail gas to perform denitration reaction, and particles in the tail gas are settled into the ash bucket.

The tail gas incineration device further comprises a steam drum and a water circulation pipeline, the water cooling wall is communicated with the steam drum through the water circulation pipeline, and the water circulation pipeline forms a supporting frame structure outside the hearth, the first flue and the second flue. The frame structure that the hydrologic cycle pipeline formed can play the effect of fixed whole incineration device, and whole tail gas incineration device need not to set up additional bearing structure for overall structure is compacter, and construction cost is also lower.

The specific structure of the hearth generally comprises an air inlet mechanism and an ignition mechanism, wherein the air inlet mechanism is used for feeding air to provide oxygen for incineration, the air inlet mechanism consists of an air box and an air distribution pipe, after the air enters the air box, the air is fed into the hearth through the air distribution pipe, the ignition mechanism ignites at the beginning of incineration, and the subsequent tail gas automatically and stably combusts by means of the combustible components of the tail gas and the air inlet of the air inlet mechanism, so that the ignition mechanism is not required to work. In order to further reduce the temperature of the flame center during incineration so as to reduce the thermal nitrogen oxides generated in the initial stage of incineration, the subsequent purified flue gas can be introduced into an air inlet mechanism through a pipeline to be mixed with air and then fed into a hearth, and the incineration temperature can be reduced by reducing the concentration of oxygen in the air inlet. For example, when the first air inlet mechanism and the second air inlet mechanism are sequentially arranged at the bottom of the hearth from bottom to top, clean flue gas and air can be selectively introduced from the first air inlet mechanism which is closer to the inlet position of the hearth, so that the flame temperature of the incineration center is reduced, and the mixed clean flue gas generally accounts for 5% -10% of the total amount of the mixed gas.

The outlet of the second flue can be connected with a flue gas purifying device to realize flue gas purification, and purified flue gas is sent into an air inlet mechanism through a flue gas pipeline to be mixed with air. The flue gas purification device can be designed conventionally according to the process requirement, for example, a deacidification tower and a dust removal tower can be arranged in sequence, and the white removal device can be used for purifying the flue gas.

In the aspect of the tail gas incineration method, the tail gas is cooled in advance, so that the content of the thermal nitrogen oxides in the initial stage of the incineration is reduced. Furthermore, the mixed gas containing clean flue gas and air can be introduced, and the mixed gas is used as primary air for incineration to reduce the concentration of oxygen, so that the reduction of the temperature of the flame center in the incineration can be assisted, and the generation of nitrogen oxides can be reduced. Finally, the temperature of the flue gas at the outlet of the hearth is controlled to be lower than 1200 ℃, so that components such as dioxin, nitrogen oxides and the like of the flue gas in the subsequent treatment process can be avoided.

Fig. 1 shows a three-section folded channel structure of a specific tail gas incinerator, which comprises a hearth 2, a first flue 7 and a second flue 10 from left to right. The main structure of the hearth 2 is a vertical square channel-shaped hearth formed by enclosing water-cooled walls, one side of the water-cooled walls in the hearth is coated with refractory materials with the thickness of 50mm, the lower part of the hearth 2 is sequentially provided with a first air distribution mechanism 6, a burner 13 and a second air distribution mechanism 8 from bottom to top, a first ash cooling hopper 16 is connected below the hearth 2, one side of the first ash cooling hopper 16 is connected with a declining inlet channel 1, the declining angle of the inlet channel 1 is 30 degrees, a cooling surface 17 opposite to the inlet channel 1 is arranged in the first ash cooling hopper 16, and the declining angle of the cooling surface is 60 degrees. The first flue 7 is a vertical square channel formed by water-cooled walls, the top of the first flue is communicated with the top of the hearth, a refractory material with the thickness of 50mm is laid at the communication position of the first flue, and a plurality of SNCR spray pipes 14 are arranged in the first flue, wherein one side of the first flue 7 adjacent to the hearth 2 shares a first water-cooled wall 18 so as to make the structure compact. The second flue 10 is a vertical square channel formed by water-cooled walls, the second flue 10 is communicated with the first flue 7 at the bottom, one side of the first flue 7 adjacent to the second flue 10 shares the same second water-cooled wall 19 so as to enable the structure to be compact, the bottoms of the first flue 7 and the second flue 10 are provided with a second ash cooling hopper 9 together, and the top of the second flue 10 is provided with an outlet. In addition to this, an emergency exhaust stack 4 is provided at the top of the furnace 2 in order to ensure the safety of the furnace 2.

The water-cooled walls at all positions are membrane-type water-cooled walls formed by carbon steel pipes with phi 51 and 6mm steel plate membranes, and the carbon steel pipes are communicated through circulating pipes and then are led into a steam drum 3 to realize waste heat utilization and continuous circulating cooling. The specific communication mode can refer to fig. 1, the circulating pipe comprises a rising pipe 21, a falling pipe 20 and a steam-water separation pipe 22, water-cooling pipelines on the water-cooling wall are respectively communicated with the rising pipe 21 and the falling pipe 20 so as to realize water circulation between the water-cooling walls and the steam drum, a steam-water mixture is formed after the water-cooling walls absorb heat and enters the steam drum through the rising pipe 21 to carry out steam-water separation, the produced steam is sent into other process sections through the steam-water separation pipe 22 to supply heat, and the cooled water in the steam drum is sent back to the cold wall through the falling pipe to carry out heat exchange, so that circulation is realized.

The first air distribution mechanism 6 and the second air distribution mechanism 8 in the hearth all adopt the existing structure. Taking the first air distribution mechanism 6 as an example. The first wind distribution mechanism 6 comprises an annular wind box and a plurality of wind distribution pipes distributed along the circumference of the inner ring of the wind box, a primary wind inlet 23 is formed in the wind box, and the outlet of the wind distribution pipe is inserted into the hearth 2, so that wind can be uniformly distributed in the hearth 2. The outlet of the second flue is connected with a flue gas purifying device to realize flue gas purification (not shown in the figure), and the purified flue gas is sent into an air inlet mechanism through a flue gas pipeline to be mixed with air. Air and clean flue gas can be sent into the bellows of the first air distribution mechanism through an air pipeline and a flue gas pipeline to form mixed gas, the clean flue gas accounts for 5% -10% of the total amount of the mixed gas, and oxygen is supplied into the hearth through an air distribution pipe for incineration.

The tail gas from the plasma incinerator at 800-1400 ℃ is led into a first ash cooling hopper 16 through an inlet channel 1 to be cooled, particles in the tail gas are cooled and settled in the ash cooling hopper 16, then the tail gas rises, the tail gas enters a hearth 2 to be incinerated, the tail gas firstly reaches the position of a first air distribution mechanism 6 to be contacted and mixed with primary air mixed with clean flue gas and air, and is continuously combusted after being ignited by a combustor 13, as the tail gas is cooled by the ash cooling hopper before being combusted, and the central temperature of flame is reduced along with the reduction of the oxygen concentration in the primary air, the amount of nitrogen oxides generated in the initial stage is reduced, the second air distribution mechanism 8 further helps combustible gas in the tail gas to burn out, the incineration temperature of the hearth exceeds 1200 ℃, the residence time of the tail gas is about 2 seconds, the flue gas at the periphery of the hearth is absorbed by a certain incineration heat, the flue gas temperature at the top of the hearth is controlled to be lower than 1200 ℃, the flue gas generated by the top of the hearth enters a first flue 7, the water cooling wall of the first flue 7 is further cooled, urea solution sprayed out by an SNCR spray pipe 14 is fully contacted with flue gas to be subjected to denitration reaction, the nitrogen oxides in the flue gas reach the first flue gas to be cooled to about 10% and the bottom of the flue gas, the flue gas reaches about 10% and the first flue gas is cooled to reach about 500%, and the second flue gas is further settled to reach the bottom of the first flue gas, and reaches the first flue gas is cooled to be about 500%, and the bottom is cooled to reach the first flue gas is cooled to reach the bottom of the first dust in the flue gas is about 10, and is cooled to reach the bottom is cooled down, and is about 9, and is cooled down in the flue gas is cooled down to reach about 5. And then the flue gas can be sent to a subsequent flue gas purification device from the outlet of the second flue 10 for purification treatment, and part of the treated clean flue gas can be sent to the first part of mechanism through a pipeline for mixing with air to form mixed gas, wherein the content of the flue gas can be 5-10% of the total amount of the mixed gas.

The examples of the present utility model are intended to be illustrative only and not to limit the scope of the claims, and other substantially equivalent substitutions will occur to those skilled in the art and are intended to be within the scope of the present utility model.

Claims (10)

1. Tail gas incineration device, including furnace, its characterized in that still includes:

a cooling device provided with a cooling channel,

the cooling channel is communicated with the bottom of the hearth, and the tail gas enters the hearth after being cooled by the cooling channel.

2. The incinerator of claim 1, wherein said cooling device is a first ash cooling hopper connected to the bottom of the furnace, and a tail gas inlet is provided on the side wall of the first ash cooling hopper.

3. An incineration device according to claim 2, further comprising an inlet channel, which inlet channel is connected obliquely downwards to the exhaust gas inlet.

4. A tail gas incineration device as claimed in claim 3, characterised in that the inlet channel is arranged opposite at least one cooling surface in the first cold ash bucket.

5. The tail gas incineration device according to claim 1, further comprising an inlet channel connected to the cooling channel, said inlet channel being constituted by a water cooled wall.

6. The tail gas incineration device as claimed in claim 1, comprising a vertical first flue and a vertical second flue, wherein the top of the first flue is connected with the furnace, the bottom of the first flue is connected with the bottom of the second flue, the flue gas of the furnace is discharged through the first flue and the second flue in sequence, the bottoms of the first flue and the second flue are jointly provided with a second ash cooling hopper, and the furnace, the first flue and the second flue are all composed of water cooling walls.

7. The tail gas incinerator of claim 6, wherein the bottoms of said first flue and said second flue have a conical ash outlet for collecting fly ash, and the bottom of said ash outlet is connected to said second ash cooling hopper.

8. The exhaust gas incinerating device according to claim 6, wherein an SNCR lance is disposed in the first flue.

9. The tail gas incinerator of claim 6, further comprising a steam drum and a water circulation pipeline, wherein the water cooling wall is communicated with the steam drum through the water circulation pipeline, and the water circulation pipeline forms a frame structure for supporting in the hearth, the first flue and the second flue.

10. The tail gas incinerator according to claim 6, wherein an air inlet mechanism is arranged on the hearth, an outlet of the second flue gas channel is connected with the flue gas purifying device, the flue gas purifying device is connected with the air inlet mechanism through the flue gas channel, and clean flue gas purified by the flue gas purifying device is sent into the air inlet mechanism through the flue gas channel.

Images