WO2017181548A1

WO2017181548A1 - Rotary kiln combustion chamber

Info

Publication number: WO2017181548A1
Application number: PCT/CN2016/091987
Authority: WO
Inventors: 胡俊杰; 李彦文; 付明录; 祁卫玺; 肖述兵; 何德成; 孙明; 朵国良
Original assignee: 朱小涛
Priority date: 2016-04-18
Filing date: 2016-07-28
Publication date: 2017-10-26
Also published as: CN205718426U

Abstract

A rotary kiln combustion chamber comprising a combustion chamber body (10) and an inlet (11) and an outlet (12) connected at two different ends of the combustion chamber body (10), said combustion chamber body (10) having barrier walls (13) projecting into the airflow path from the internal wall thereof; by means of the barrier walls (13) projecting from the inner wall of the combustion chamber body (10), passing airflow may be impeded in the airflow path. Airflow colliding with a corresponding barrier wall (13) generates reversals, lengthening the airflow flow path and lowering flow speed, increasing the combustion rate of not fully combusted volatiles in the flue gas and dust in the airflow; this also increases the degree of precipitation in the combustion chamber body (10), decreasing deposition effects in the waste heat boiler.

Description

Rotary kiln combustion chamber

Technical field

The invention relates to the technical field of rotary kiln, in particular to a rotary kiln combustion chamber.

Background technique

In the electrolytic aluminum carbon system, the raw material enters from the kiln tail, and the material calcined at a high temperature in the kiln enters the cooling machine from the kiln head through the moving chute. In the process, relying on the negative pressure of the induced draft fan, the unburned volatiles in the flue gas and part of the dust are transferred to the post-kiln combustion chamber for secondary combustion, and then enter the waste heat boiler.

The raw material is fully burned into a calcined coke, and if the dust and volatile matter in the combustion chamber cannot be fully burned or deposited, it will enter the waste heat boiler, causing the boiler to easily accumulate too much dust, causing the boiler differential pressure to be too large, affecting safe operation, resulting in the boiler stopping. When the rotary kiln was forced to stop the kiln, the lining life was damaged.

At present, in the design of the rotary kiln body, the sedimentation chamber is used after the small and medium-sized rotary kiln, and the sedimentation chamber can fully realize the dust deposition, but it is difficult to realize the re-burning of the volatile matter in the flue gas, and the utilization efficiency of the waste heat cannot be improved. The combustion chamber is usually used after the large rotary kiln, and the combustion chamber can realize secondary combustion of volatiles in the flue gas, increase the temperature of the flue gas, improve the utilization efficiency of waste heat, and realize waste heat power generation.

However, the direct combustion chamber behind the large rotary kiln is the patented technology of Metso Kiln. The technical principle of the combustion chamber is that the dust and the unburned volatiles are both burned in the combustion chamber. The U-shaped combustion chamber is lower than the Metso kiln combustion chamber. In actual production, since the dust flows through the flue gas, although some dust and volatile matter can be fully burned in the U-shaped combustion chamber, there is still a lot of dust passing through. The flue gas flow enters the waste heat boiler, resulting in serious accumulation of ash in the waste heat boiler. The shortest one takes 1 month to stop the kiln and clear the ash. This has led to an increase in the number of starts and stops of the rotary kiln, which has a great impact on the entire production balance and even the lining of the rotary kiln.

Summary of the invention

In view of the deficiencies of the prior art, the present invention provides a rotary kiln combustion chamber, which can reduce the deposition effect in the waste heat boiler, ensure the boiler pressure difference and its normal operation and protect the rotary kiln lining.

In order to achieve the above object, the present invention adopts the following technical solutions:

A rotary kiln combustion chamber comprising a combustion chamber body and two respectively connected to the combustion chamber body At the same end of the inlet and outlet, the combustion chamber body protrudes from the inner wall toward the air flow passage with a barrier wall.

Wherein, the combustion chamber body is formed by at least three stages of bending, and the inlet and the outlet are respectively disposed at both ends of the combustion chamber body.

Alternatively, the combustion chamber body is of a straight cylinder type.

Wherein the barrier wall is perpendicular to the direction of the airflow.

Wherein at least one of the barrier walls is inclined toward the outlet direction.

Wherein, the barrier wall is plural, and at least one of the barrier walls has a height different from that of the other barrier walls.

Wherein the rotary kiln combustion chamber comprises a barrier wall located in the middle of one inner wall and a barrier wall on both sides of the barrier wall in the middle portion and adjacent to the inlet and the outlet respectively, the central barrier wall having the lowest height .

Wherein, at least two inner walls on both sides of the airflow direction of the combustion chamber body are provided with the barrier wall.

Wherein, the barrier walls on the opposite inner walls of the combustion chamber body are spaced apart and alternately arranged in the direction of the air flow.

Wherein the barrier walls on the opposite inner walls of the combustion chamber body are staggered in a direction perpendicular to the direction of the air flow.

By extending a barrier wall on the inner wall of the combustion chamber body, the airflow passage can block the passing airflow, and the airflow collides with the corresponding barrier wall to generate a foldback, which increases the flow path of the airflow and reduces the flow speed thereof. The combustion rate of unburned sufficient volatiles in the flue gas and dust in the airflow and the degree of precipitation in the combustion chamber body are improved, and the deposition effect in the waste heat boiler is reduced.

DRAWINGS

1 is a schematic view showing the structure of a combustion chamber according to Embodiment 1 of the present invention.

2 is a comparison of parameters of a combustion chamber according to Embodiment 1 of the present invention before and after a barrier wall is provided on a bottom wall of a horizontal section of a U-shaped combustion chamber body.

Figure 3 is a schematic view showing the structure of a combustion chamber according to Embodiment 2 of the present invention.

Figure 4 is a schematic view showing the structure of a combustion chamber according to Embodiment 3 of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

Referring to Fig. 1, the rotary kiln combustion chamber of the present embodiment includes a combustion chamber body 10 and an inlet 11 and an outlet 12 respectively connected at two different ends of the combustion chamber body 10, and the combustion chamber body 10 protrudes from the inner wall toward the air flow passage with a barrier wall 13 .

Wherein, the combustion chamber body 10 of the present embodiment is U-shaped, including a horizontal section 10a fixed on a support portion such as the ground and a vertical inlet section 10b, an outlet section 10c, an inlet 11 and a top portion of the horizontal section 10a. The outlets 12 are respectively connected to the inlet section 10b and the outlet section 10c at both ends of the combustion chamber body 10. The flue gas and part of the dust discharged from the rotary kiln enter the combustion chamber from the inlet section 10b, and are discharged from the outlet section 10c after the secondary combustion through the horizontal section 10a. It is discharged to the waste heat boiler, and by increasing the temperature of the flue gas, the utilization efficiency of waste heat can be increased.

Wherein, there are a plurality of barrier walls 13, each barrier wall 13 is perpendicular to the airflow direction X of the corresponding section thereof, so that the airflow has the most direct blocking effect, and the blocked airflow is mostly perpendicular to the barrier wall 13 The flow forms convection with the inflowing airflow behind, reducing the flow rate of the airflow. Further, the height of the at least one barrier wall 13 is different from the other barrier walls 13. Here, the horizontal section 10a of the rotary kiln combustion chamber includes a barrier wall 13 in the middle of one inner wall and a barrier wall 13 on both sides of the barrier wall 13 in the middle and adjacent to the inlet 11 and the outlet 12, respectively, and the central barrier wall 13 has the lowest height. The barrier wall 13 at both ends is higher than the intermediate barrier wall 13 so that the airflow at both ends can be blocked by the barrier wall just after entering the horizontal section 10a. After the barrier wall 13 near the inlet 11 and the inner wall of the end are folded back, the airflow flows through The central barrier wall 13 and the central barrier wall 13 have the lowest velocity, so that the gas accelerates and collides to the barrier wall 13 near the outlet 12, and then accelerates and folds back, and the rear airflow again forms a sharp collision deceleration, increasing the flow path of the airflow and slowing down the flow rate. At the same time, it also prolongs the time of secondary combustion and improves the combustion efficiency. At the same time, each of the barrier walls 13 can produce a reentry function, and can function to block the precipitated flue gas and the particulate matter in a part of the dust to float again.

Wherein, the height of the barrier wall 13 in the middle is 1.3 m, the height of the barrier wall 13 near the inlet 11 and the outlet 12 is 2.5 m, and the end of the horizontal section 10a near the inlet 11 is provided with a 24 cm thick refractory brick layer, and the barrier wall 13 is A 37 cm thick refractory brick layer, the barrier wall 13 near the inlet 11 is about 3.8 m from its nearest end, and the barrier wall 13 near the outlet 12 is about 3.5 m from its nearest end.

FIG. 2 is a comparison of parameters before and after the barrier wall 13 is disposed on the bottom wall of the horizontal section 10a of the U-shaped combustion chamber body 10. According to the chart, after the barrier wall is set, the temperature of the A and the kiln head is lowered, and the temperature of the calcination zone is lowered. The control is stable, and the exit temperature of the combustion chamber is significantly reduced by 50-1000C, both within the design value. B. The vacuum pressure control of the kiln head and the kiln tail is stable, and the frequency of the main induced draft fan is reduced by about 10HZ. It is stable before operation and has obvious power saving. C. The amount of dust in the flue gas is significantly reduced, and the ash accumulation of the waste heat boiler economizer is greatly reduced. It is once cleaned every two months and reduced to at least four months of cleaning.

This embodiment only shows the case where the inner wall of the lower portion of the horizontal section 10a of the U-shaped combustion chamber body 10 is provided with the barrier wall 13. It can be understood that the inlet section 10b and the outlet section 10c of the U-shaped combustion chamber body 10 can also be disposed. There is a corresponding barrier wall 13. The barrier wall 13 is also applicable to other shapes of the combustion chamber body, such as "S" shape, "Z" shape, "W" shape, "V" shape, and straight type.

Example 2

As shown in Fig. 3, unlike the first embodiment, at least one of the barrier walls 13 of the present embodiment is inclined toward the outlet 12. For example, the barrier wall 13 near the inlet 11 is inclined toward the inlet 11, and the top portion thereof forms a constricted space with the adjacent inner wall of the end portion, and the airflow flowing in from the inlet 11 enters the constricted wall along the barrier wall 13 and the detour path is extended again. Similarly, the inclination of the barrier wall 13 near the outlet 12 can also form a space for the constriction with the adjacent barrier wall 13 or the end inner wall adjacent thereto, extending the path of the corresponding portion, indirectly prolonging the combustion and precipitation time.

Example 3

As shown in Fig. 4, unlike the first embodiment, the inner walls of the horizontal section 10a of the airflow direction X of the combustion chamber body 10 of the present embodiment are each provided with a barrier wall 13. In addition, the inner walls of the inlet section 10b and the outlet section 10c may also be provided with a barrier wall 13.

Here, the barrier walls 13 on the upper and lower walls of the horizontal section 10a are spaced apart and alternately arranged in the direction of the airflow X, i.e., the barrier walls 13 on both are staggered in the direction of the airflow X. Wherein, the barrier walls 13 on the two inner walls are staggered in a direction perpendicular to the airflow direction X, that is, the barrier walls 13 on the two partially overlap in the extending direction to form a circuitous path, increasing the number of collisions between the airflow and the barrier wall 13 and The number of collisions between airflow and airflow.

By extending a barrier wall on the inner wall of the combustion chamber body, the airflow passage can block the passing airflow, and the airflow collides with the corresponding barrier wall to generate a foldback, which increases the flow path of the airflow and reduces the flow speed thereof. The combustion rate of unburned sufficient volatiles in the flue gas and dust in the airflow and the degree of precipitation in the combustion chamber body are improved, and the deposition effect in the waste heat boiler is reduced. The The technology is universal in U-shaped combustion chamber application, suitable for all large rotary kiln combustion chambers. It can be used by carbon enterprises and electrolytic aluminum enterprises in China to build large-scale rotary kiln. It can also be used in similar occasions in other industries. Good promotion value.

The above description is only a specific embodiment of the present application, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present application. It should be considered as the scope of protection of this application.

Claims

A rotary kiln combustion chamber, comprising a combustion chamber body and an inlet and an outlet respectively connected at two different ends of the combustion chamber body, the combustion chamber body projecting a barrier wall from the inner wall toward the air flow passage.
The rotary kiln combustion chamber according to claim 1, wherein said combustion chamber body comprises at least three stages of bending, and said inlet and said outlet are respectively provided at both ends of said combustion chamber body.
The rotary kiln combustion chamber according to claim 1, wherein the combustion chamber body is of a straight cylinder type.
A rotary kiln combustion chamber according to claim 1 wherein said barrier wall is perpendicular to the direction of the gas flow.
A rotary kiln combustion chamber according to claim 1, wherein at least one of said barrier walls is inclined toward said outlet direction.
A rotary kiln combustion chamber according to claim 1, wherein said barrier wall is plural, and at least one of said barrier walls has a height different from that of the other barrier walls.
A rotary kiln combustion chamber according to claim 6, comprising a barrier wall located in the middle of one inner wall and a barrier wall on both sides of said central barrier wall and adjacent to said inlet and said outlet, respectively, said central portion The barrier wall has the lowest height.
The rotary kiln combustion chamber according to claim 6, wherein at least two inner walls of both sides of the gas flow direction of the combustion chamber body are provided with the barrier wall.
A rotary kiln combustion chamber according to claim 8, wherein said barrier walls on opposite inner walls of said combustion chamber body are spaced apart and alternately arranged in the direction of the air flow.
A rotary kiln combustion chamber according to claim 9, wherein said barrier walls on opposite inner walls of said combustion chamber body are staggered in a direction perpendicular to the direction of the gas flow.
The rotary kiln combustion chamber according to claim 2, wherein said barrier wall is plural, and at least one of said barrier walls has a height different from that of the other barrier walls.
A rotary kiln combustion chamber according to claim 11, comprising a barrier wall in the middle of one inner wall and a barrier wall on both sides of said central barrier wall and adjacent to said inlet and said outlet, respectively, said central portion The barrier wall has the lowest height.
The rotary kiln combustion chamber according to claim 11, wherein the combustion chamber body has an air flow The barrier wall is provided on at least two inner walls of both sides of the direction.
A rotary kiln combustion chamber according to claim 13, wherein said barrier walls on opposite inner walls of said combustion chamber body are spaced apart and alternately arranged in the direction of the air flow.
A rotary kiln combustion chamber according to claim 14, wherein said barrier walls on opposite inner walls of said combustion chamber body are staggered in a direction perpendicular to the direction of the gas flow.
A rotary kiln combustion chamber according to claim 5, wherein said barrier wall is plural, and at least one of said barrier walls has a height different from that of the other barrier walls.
A rotary kiln combustion chamber according to claim 16, comprising a barrier wall in the middle of one inner wall and a barrier wall on both sides of said central barrier wall and adjacent to said inlet and said outlet, respectively, said central portion The barrier wall has the lowest height.
The rotary kiln combustion chamber according to claim 16, wherein at least two inner walls of both sides of the gas flow direction of the combustion chamber body are provided with the barrier wall.
A rotary kiln combustion chamber according to claim 18, wherein said barrier walls on opposite inner walls of said combustion chamber body are spaced apart and alternately arranged in the direction of the air flow.
A rotary kiln combustion chamber according to claim 19, wherein said barrier walls on opposite inner walls of said combustion chamber body are staggered in a direction perpendicular to the direction of the gas flow.