A flue gas heat extraction device for a mixed-burning lime shaft kiln

Abstract

The present invention discloses a heat extraction device for a mixed-burned lime vertical kiln. The heat extraction device for a mixed-burned lime vertical kiln comprises a newly added annular steel sleeve and an annular flue gas duct in the kiln body. The sleeve penetrates into the kiln body at a position about 400°C below the material surface, and the sleeve and the inner wall of the vertical kiln form a cavity. The flue gas rising along the inner wall of the kiln body passes through the cavity upward into the annular flue provided on the uppermost layer, and then is connected to the kiln body through two pipes. The newly added hot flue gas duct is mixed with the original kiln body's flue gas duct to raise the flue gas temperature to 240-280°C, which meets the high-temperature environment for the normal use of the denitrification catalyst, avoids the high energy required for additional heating, and saves production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas denitrification, in particular to a flue gas heat extraction device for a mixed-burning lime shaft kiln. Background Art

[0002] Currently, flue gas denitrification methods primarily include SCR, SNCR, and combined SCR / SNCR technologies. Denitrification catalysts are the core and key to these treatment systems. For example, SCR denitrification uses ammonia, CO, or hydrocarbons as reducing agents in the presence of oxygen, reducing NO in the flue gas to N2. Suitable reducing agents for the SCR reaction include NH3, CO, H2, as well as methane, ethylene, propane, and propylene.

[0003] The operating temperature of conventional denitrification catalysts currently on the market is 180-600°C. However, the flue gas temperature at the top of the mixed-burning lime shaft kiln is 120-200°C. If the flue gas enters the denitrification device directly, no matter which denitrification process is used, it cannot meet the temperature conditions for the normal use of the denitrification catalyst. If the temperature conditions cannot be met, the denitrification catalyst will not be able to play a catalytic role, which will have a significant impact on the denitrification work. However, if the flue gas temperature is increased by additional heating, the corresponding heating device must be established first, and a large amount of heat source or gas is also required. This heating method will incur huge operating expenses, resulting in a sharp increase in production costs, making it unsuitable for large-scale use in factories. Summary of the Invention

[0004] The object of the present invention is to provide a flue gas heat extraction device for a mixed-burning lime shaft kiln to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a hot flue gas extraction device for a mixed-burning lime vertical kiln, comprising a sleeve and a hot flue gas annular pipe, wherein the sleeve is installed in the inner cavity of the lime kiln, and the sleeve extends below the material surface to form an annular cavity with the inner wall of the lime kiln. The annular cavity is used as a hot flue gas annular pipe on the top of the refractory bricks inside the kiln body. After being led out of the kiln body through two hot flue gas branch pipes, it is merged into a hot flue gas main pipe at the top of the kiln and connected to the mixed flue gas pipe together with the existing kiln top flue gas main pipe, and then connected to a cyclone dust collector to remove large particles of smoke, thereby providing flue gas with low dust content and temperature that meets the requirements for the subsequent desulfurization and denitrification system.

[0006] Preferably, the sleeve extends into the area 400°C below the material surface in the lime kiln, and the sleeve and the inner wall of the lime kiln form an annular cavity, which is used to achieve uniform heat extraction.

[0007] Preferably, the annular cavity is connected to a hot flue gas ring pipe installed on the top of the refractory layer.

[0008] Preferably, the hot flue gas is directly mixed with the existing flue gas.

[0009] Preferably, electric regulating valves are provided on the hot flue gas main and the existing kiln top flue gas main, and a temperature sensor is provided on the mixed flue gas pipe to control the temperature of the mixed flue gas within the range of 240-280°C.

[0010] Preferably, a cyclone dust collector is installed on the pipeline of the mixed flue gas pipe to ensure the stable operation of the subsequent desulfurization and denitrification system.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. The hot flue gas extraction device for the mixed-burning lime shaft kiln utilizes a sleeve, an annular cavity, a hot flue gas annular pipe, a hot flue gas branch pipe, and a hot flue gas main pipe. The sleeve extends into the kiln material layer at a temperature of approximately 400°C. The sleeve and the kiln inner wall form a cavity, through which the hot flue gas flows upward into the annular flue before exiting the kiln through the hot flue gas branch pipe. Finally, it mixes with the flue gas from the existing kiln roof flue gas main pipe in the mixed flue gas pipe. This mixing raises the flue gas temperature, meeting the high-temperature requirements for normal operation of the denitrification catalyst, while also avoiding the high energy required for additional heating and saving production costs.

[0013] 2. The flue gas heat extraction device for the mixed lime shaft kiln utilizes a temperature sensor, electric control valve, and thermometer to raise the flue gas temperature after mixing. After large dust particles are removed by a cyclone dust collector, the flue gas enters the medium-temperature SCR denitrification system through a pipeline. The temperature sensor and electric control valve output the reading of the thermometer in the pipe and flexibly adjust the opening of the electric control valve according to the temperature requirements of the subsequent system, controlling the flue gas flow in the pipeline to ensure that the mixed flue gas temperature meets the required level. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention.

[0015] Figure 2 It is the front view of the present invention.

[0016] In the figure: 1. Sleeve; 2. Annular cavity; 3. Hot flue gas ring pipe; 4. Hot flue gas branch pipe; 5. Hot flue gas main pipe; 6. Electric regulating valve; 8. Existing kiln top flue gas main pipe; 10. Mixed flue gas pipe; 11. Lime kiln; 12. Cyclone dust collector; 13. Temperature sensor. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] See also Figure 1-2 The present invention provides a technical solution: a hot flue gas extraction device for a mixed-burning lime shaft kiln, comprising a sleeve 1 and a hot flue gas ring pipe 3. The sleeve 1 is installed in the inner cavity of the lime kiln 11, and the sleeve 1 extends below the material surface to form an annular cavity 2 with the inner wall of the lime kiln 11. The annular cavity 2 is used as a hot flue gas ring pipe 3 on the top of the refractory bricks inside the kiln body. After being led out of the kiln body through two hot flue gas branch pipes 4, it merges into a hot flue gas main pipe 5 at the top of the kiln and is connected to a mixed flue gas pipe 10 together with the existing kiln top flue gas main pipe 8, and then connected to a cyclone dust collector 12 to remove large particles of smoke, thereby providing flue gas with low dust content and temperature that meets the requirements for the subsequent desulfurization and denitrification system.

[0019] In this embodiment, the flue gas generated in the lime kiln 11 continuously moves upward along the kiln body. Part of the flue gas is discharged along the existing flue gas pipe on the top of the kiln body of the lime kiln 11, and part of the flue gas enters the hot flue gas ring pipe 3 along the annular cavity 2, and then enters the hot flue gas main pipe 5 through the confluence of the hot flue gas branch pipe 4, and finally enters the mixed flue gas pipe 10 together with the flue gas in the existing kiln top flue gas main pipe of the kiln body to be mixed. After mixing, the flue gas temperature is increased to meet the high temperature environment for normal use of the denitrification catalyst, and the high energy required for additional heating is avoided, thereby saving production costs.

[0020] Furthermore, the sleeve 1 extends into the area 400°C below the material surface in the lime kiln 11, and the sleeve 1 and the inner wall of the lime kiln 11 form an annular cavity 2, which is used to achieve uniform heat extraction.

[0021] Furthermore, the annular cavity 2 is connected to the hot flue gas ring pipe 3 installed on the top of the refractory layer.

[0022] Furthermore, the hot flue gas is directly mixed with the existing flue gas.

[0023] Furthermore, electric regulating valves 6 are provided on the hot flue gas main pipe 5 and the existing kiln top flue gas main pipe 8, and a temperature sensor 13 is provided on the mixed flue gas pipe 10 to control the temperature of the mixed flue gas within the range of 250-280°C.

[0024] Furthermore, a cyclone dust collector 12 is installed on the pipeline of the mixed flue gas pipe 10 to ensure the temperature operation of the subsequent desulfurization and denitrification system. The temperature sensor and the electric regulating valve can output the reading of the thermometer in the pipe and flexibly adjust the opening of the electric regulating valve according to the temperature requirements of the subsequent system to control the flue gas flow in the pipeline, so that the temperature of the mixed flue gas meets the requirements.

[0025] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A hot flue gas extraction device for a mixed-burning lime shaft kiln, comprising a sleeve (1) and a hot flue gas annular pipe (3), characterized in that: The sleeve (1) is installed in the inner cavity of the lime kiln (11), and the sleeve (1) extends below the material surface to form an annular cavity (2) with the inner wall of the lime kiln (11). The annular cavity (2) is used as a hot flue gas ring pipe (3) on the top of the refractory brick inside the kiln body. After being led out of the kiln body through two hot flue gas branch pipes (4), it merges into a hot flue gas main pipe (5) at the top of the kiln and is connected to the mixed flue gas pipe (10) together with the existing kiln top flue gas main pipe (8), and then connected to a cyclone dust collector (12) to remove large particles of smoke dust, thereby providing flue gas with low dust content and temperature that meets the requirements for the subsequent desulfurization and denitrification system.

2. The heat extraction flue gas device for a mixed-burning lime shaft kiln according to claim 1, characterized in that: The sleeve (1) extends into a region 400°C below the material surface in the lime kiln (11), and the sleeve (1) and the inner wall of the lime kiln (11) form an annular cavity (2), which is used to achieve uniform heat extraction.

3. The heat extraction flue gas device for a mixed-burning lime shaft kiln according to claim 1, characterized in that: The annular cavity (2) is connected to a hot flue gas annular pipe (3) installed on the top of the fireproof layer.

4. The heat extraction flue gas device for a mixed-burning lime shaft kiln according to claim 1, characterized in that: Electric regulating valves (6) are respectively provided on the hot flue gas main pipe (5) and the existing kiln top flue gas main pipe (8), and a temperature sensor (13) is provided on the mixed flue gas pipe (10) to control the temperature of the mixed flue gas within the range of 240 to 280°C.

5. The heat extraction flue gas device for a mixed-burning lime shaft kiln according to claim 1, characterized in that: A cyclone dust collector (12) is installed on the mixed flue gas pipe (10) to ensure the stable operation of the subsequent desulfurization and denitrification system.

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