Novel energy-saving full-automatic environment-friendly lime kiln capable of reducing nitrogen oxides

Abstract

The utility model discloses a novel full-automatic environment-friendly lime kiln capable of saving energy and reducing nitrogen oxides, which relates to the technical field of lime kilns and comprises a lime kiln, an air inlet pipe of the lime kiln is connected with a shunt pipe in parallel, the shunt pipe is connected with a venturi pipe in series, and a throat pipe part of the venturi pipe is connected with an air suction pipe. The air inlet end of the air suction pipe is communicated with the smoke exhaust pipe, and the Venturi pipe is used for forming negative pressure to suck smoke; the smoke exhaust device further comprises a heat exchanger, the smoke exhaust pipe and the air inlet pipe are connected with a hot flow channel and a cold flow channel of the heat exchanger respectively, the air inlet pipe is connected with an air feeder, and the air feeder is used for introducing air. According to the novel energy-saving full-automatic environment-friendly lime kiln capable of reducing the nitrogen oxides, the oxygen content of supplied air can be controlled under the condition that the air speed is not reduced, so that the generation of the nitrogen oxides is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of lime kilns, and particularly relates to a fully automatic environmental protection lime kiln with novel energy saving and reduced nitrogen oxides. Background Technique

[0002] A lime kiln is a device used for producing lime and is used to complete the calcination process of limestone. During the calcination process, fuel combustion will generate nitrogen oxides that pollute the environment. The generation of its nitrogen oxides mainly includes the following reasons:

[0003] 1. Combustion temperature: When the combustion temperature is lower than 1400 °C, the generation rate of thermal NOx is slower; when the temperature is higher than 1400 °C, the reaction significantly accelerates and the generation amount of NOx significantly increases. 2. Excess air coefficient: That is, the ratio of the actual oxygen supply to the theoretical oxygen demand. When the excess air coefficient decreases, the generation amount of NOx also decreases. This is because in an oxygen-deficient state, the nitrogen volatilized from the fuel competes with carbon and hydrogen for the insufficient oxygen. Since nitrogen lacks competitiveness, the formation of NOx is reduced. 3. Residence time of flue gas in the high-temperature zone: The generation of thermal NOx is also related to the residence time of flue gas in the high-temperature zone. The longer the residence time, the more NOx is generated.

[0004] As can be seen from the above, during the combustion process of a lime kiln, there is a significant mutual influence relationship between the combustion temperature and the oxygen supply. Excessively high oxygen content often leads to overheating of the combustion temperature, which not only affects the combustion efficiency but may also damage the equipment inside the kiln. In order to precisely control the combustion temperature and optimize the combustion efficiency, currently, the method of adjusting the air volume of the blower is generally used to adjust the oxygen content entering the kiln. However, although reducing the air volume of the blower can effectively reduce the oxygen supply, it will correspondingly extend the residence time of the flue gas in the high-temperature zone, which will instead promote the generation of thermal NOx and increase the emission of nitrogen oxides.

[0005] Therefore, it is very necessary to propose a fully automatic environmental protection lime kiln with novel energy saving and reduced nitrogen oxides to solve the above problems. Content of the Utility Model

[0006] (I) Technical Problems to be Solved

[0007] The purpose of the utility model is to provide a fully automatic environmental protection lime kiln with novel energy saving and reduced nitrogen oxides to solve the problems raised in the above background technique.

[0008] (II) Technical Solution

[0009] To achieve the above object, the utility model is realized through the following technical solutions: A new type of fully automatic environmental protection lime kiln for energy conservation and reduction of nitrogen oxides, including a lime kiln. A shunt pipe is connected in parallel to the air inlet pipe of the lime kiln. A Venturi tube is connected in series to the shunt pipe. The throat part of the Venturi tube is connected with an air suction pipe. The air inlet end of the air suction pipe is communicated with the smoke exhaust pipe. The Venturi tube is used to form a negative pressure to suck in the flue gas.

[0010] It also includes a heat exchanger. The smoke exhaust pipe and the air inlet pipe are respectively connected to the heat flow channel and the cold flow channel of the heat exchanger. A blower is connected to the air inlet pipe. The blower is used to introduce air.

[0011] Preferably, an on-line nitrogen oxide detection device is provided on the smoke exhaust pipe of the lime kiln.

[0012] Preferably, a cyclone dust collector and a bag filter are successively connected to the smoke exhaust pipe. The cyclone dust collector and the bag filter are respectively located on the air inlet side and the air outlet side of the heat flow channel of the heat exchanger.

[0013] Preferably, the on-line nitrogen oxide detection device is located on the air outlet side of the bag filter. The air outlet of the bag filter is connected with an induced draft fan.

[0014] Preferably, a buffer tank is connected in series to the smoke exhaust pipe between the cyclone dust collector and the heat exchanger. The air suction pipe is connected with the buffer tank.

[0015] Preferably, a flow regulating valve is provided on the air inlet side of the Venturi tube, and a check valve is provided on the air outlet side of the Venturi tube.

[0016] Preferably, one end of the air inlet pipe located inside the lime kiln is fixedly connected with an air cap.

[0017] Preferably, gas flow sensors are provided on both the air suction pipe and the air inlet pipe.

[0018] (III) Beneficial effects

[0019] Compared with the prior art, the utility model provides a new type of fully automatic environmental protection lime kiln for energy conservation and reduction of nitrogen oxides, which has the following beneficial effects:

[0020] 1. For the new type of fully automatic environmental protection lime kiln for energy conservation and reduction of nitrogen oxides, by arranging a Venturi tube in parallel on the air inlet pipe, using the negative pressure generated by it to suck the flue gas in the smoke exhaust pipe into the air inlet pipe to mix with the air, so as to control the oxygen content in the inlet air, reduce the peak flame temperature and the air excess coefficient, thereby controlling the generation of nitrogen oxides, and at the same time, it can avoid the increase of the residence time of the flue gas in the high-temperature area.

[0021] 2. By using the heat exchanger to preheat the air with the high-temperature flue gas, the heat loss of the lime kiln is reduced, making it more energy-efficient. Brief Description of the Drawings

[0022] Figure 1 This is a schematic flow diagram of the present utility model.

[0023] In the figure: 1, lime kiln; 2, air cap; 3, cyclone dust collector; 4, suction pipe; 5, shunt pipe; 6, buffer tank; 7, heat exchanger; 8, bag filter; 9, on-line NOx detection device; 10, induced draft fan; 11, check valve; 12, Venturi tube; 13, flow regulating valve; 14, forced draft fan. Detailed Embodiments

[0024] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0025] Please refer to Figure 1 As shown, a new type of fully automatic environmental protection lime kiln for energy saving and reducing nitrogen oxides includes a lime kiln 1. A shunt pipe 5 is connected in parallel on the air inlet pipe of the lime kiln 1. A Venturi tube 12 is connected in series on the shunt pipe 5. The throat part of the Venturi tube 12 is connected with a suction pipe 4. The air inlet end of the suction pipe 4 is communicated with the exhaust pipe. The Venturi tube 12 is used to form a negative pressure to suck in the flue gas. It also includes a heat exchanger 7. The exhaust pipe and the air inlet pipe are respectively connected to the heat flow channel and the cold flow channel of the heat exchanger 7. A forced draft fan 14 is connected to the air inlet pipe. The forced draft fan 14 is used to introduce air.

[0026] During operation, the air introduced by the forced draft fan 14 exchanges heat with the high-temperature flue gas through the heat exchanger 7 to preheat the air, improve the air supply temperature, and reduce the heat loss of the lime kiln 1 caused by the air supply. Part of the air is shunted by the shunt pipe 5 and flows through the Venturi tube 12. Under the action of the Venturi tube 12, a negative pressure is formed in the suction pipe 4 to pump the high-temperature flue gas into the shunt pipe 5. The air and the high-temperature flue gas are mixed in the air inlet pipe and enter the lime kiln 1. By circulating part of the high-temperature flue gas into the lime kiln 1, the oxygen concentration in the mixed gas is reduced, and the peak flame temperature is reduced, thereby controlling the generation of nitrogen oxides.

[0027] In order to facilitate the detection of the nitrogen oxide content in the flue gas, an on-line NOx detection device 9 is provided on the exhaust pipe of the lime kiln 1. According to the detected content, the mixing ratio of air and flue gas is adjusted to control the air excess coefficient, avoiding being too large or too small to ensure complete combustion. If the air excess coefficient is too large, the generation amount of nitrogen oxides will increase; if the air excess coefficient is too small, the combustion efficiency will be affected.

[0028] In some embodiments, a cyclone dust collector 3 and a bag filter 8 are successively connected to the exhaust pipe. By providing the cyclone dust collector 3 and the bag filter 8, the dust in the high-temperature flue gas is filtered in stages to reduce environmental pollution. Preferably, the cyclone dust collector 3 and the bag filter 8 are respectively located on the air inlet side and the air outlet side of the heat flow channel of the heat exchanger 7. By arranging the cyclone dust collector 3 on the air outlet side of the heat flow channel of the heat exchanger 7, the dust content is reduced to avoid blockage of the heat exchanger 7. By arranging the bag filter 8 on the air outlet side of the heat flow channel of the heat exchanger 7, the flue gas temperature is reduced to prevent damage to the filter bag.

[0029] To avoid the influence of high temperature and dust on the service life and detection accuracy of the on-line NOx detection device 9, the on-line NOx detection device 9 is located on the air outlet side of the bag filter 8. The air outlet of the bag filter 8 is connected to an induced draft fan 10 for exhausting smoke.

[0030] To reduce the influence of the flue gas flow rate on the negative pressure suction of the Venturi tube 12, a buffer tank 6 is connected in series on the exhaust pipe between the cyclone dust collector 3 and the heat exchanger 7. The suction pipe 4 is connected to the buffer tank 6. By means of the buffer tank 6, the flue gas flow rate is reduced, making the suction through the suction pipe 4 smoother and more uniform.

[0031] To facilitate the control of the oxygen content in the mixed gas, that is, the mixing ratio of air and flue gas, a flow regulating valve 13 is provided on the air inlet side of the Venturi tube 12. By adjusting the flow regulating valve 13, the air ratio entering the shunt pipe 5 is adjusted, the air flow rate flowing through the Venturi tube 12 is controlled, and the magnitude of the negative pressure generated by the Venturi tube 12 is adjusted to realize the regulation of the flue gas suction volume, thereby realizing the regulation of the flue gas ratio. To prevent air from flowing backward in the shunt pipe 5, a check valve 11 is provided on the air outlet side of the Venturi tube 12.

[0032] Specifically, one end of the air inlet pipe located inside the lime kiln 1 is fixedly connected with an air cap 2. By providing the air cap 2, air can be dispersed and conveyed into the lime kiln 1.

[0033] To facilitate the detection of the ratio of air to flue gas, gas flow sensors are provided on both the suction pipe 4 and the air inlet pipe.

[0034] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new type of fully automatic environmental protection lime kiln with energy saving and nitrogen oxide reduction, comprising a lime kiln (1), characterized in that: A shunt pipe (5) is connected in parallel to the air inlet pipe of the lime kiln (1). A Venturi tube (12) is connected in series to the shunt pipe (5). An air suction pipe (4) is connected to the throat part of the Venturi tube (12). The air inlet end of the air suction pipe (4) is communicated with the smoke exhaust pipe. The Venturi tube (12) is used to form a negative pressure to suck in the flue gas; It further includes a heat exchanger (7). The smoke exhaust pipe and the air inlet pipe are respectively connected to the heat flow channel and the cold flow channel of the heat exchanger (7). A blower (14) is connected to the air inlet pipe. The blower (14) is used to introduce air.

2. The fully automatic environmental protection lime kiln for a new type of energy saving and nitrogen oxide reduction according to claim 1, characterized in that: An on-line nitrogen oxide detection device (9) is provided on the smoke exhaust pipe of the lime kiln (1).

3. A novel energy-saving and nitrogen oxide-reducing fully automatic environmental protection lime kiln according to claim 1, characterized in that: A cyclone dust collector (3) and a bag filter (8) are sequentially connected to the smoke exhaust pipe. The cyclone dust collector (3) and the bag filter (8) are respectively located on the air inlet side and the air outlet side of the heat flow channel of the heat exchanger (7).

4. A novel energy-saving and NOx-reducing fully automatic environmental protection lime kiln according to claim 2, characterized in that: The on-line nitrogen oxide detection device (9) is located on the air outlet side of the bag filter (8). The air outlet of the bag filter (8) is connected to a draught fan (10).

5. A novel energy-saving and NOx-reducing fully automatic environmental protection lime kiln according to claim 3, characterized in that: A buffer tank (6) is connected in series to the smoke exhaust pipe between the cyclone dust collector (3) and the heat exchanger (7). The air suction pipe (4) is connected to the buffer tank (6).

6. The fully automatic environmental protection lime kiln for a new type of energy saving and reducing nitrogen oxides according to claim 1, characterized in that: A flow regulating valve (13) is provided on the air inlet side of the Venturi tube (12). A check valve (11) is provided on the air outlet side of the Venturi tube (12).

7. A novel energy-saving and NOx-reducing fully automatic environmental protection lime kiln according to claim 1, characterized in that: One end of the air inlet pipe located inside the lime kiln (1) is fixedly connected to an air cap (2).

8. A novel energy-saving and nitrogen oxide-reducing fully automatic environmental protection lime kiln according to claim 1, characterized in that: Gas flow sensors are provided on both the air suction pipe (4) and the air inlet pipe.

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