Energy-saving device for hazardous waste incineration flue gas treatment

Abstract

The utility model discloses an energy-saving device for hazardous waste incineration flue gas treatment, which comprises a hazardous waste treatment system and an energy circulation system which are matched with each other, and the hazardous waste treatment system comprises a rotary kiln (1), a secondary combustion chamber (2), a waste heat boiler (3) and a dry deacidification and bag-type dust collector (4), the energy circulation system comprises a flue gas heat collector (5), a wet slag drying system (6), a primary air heater (7), a secondary air heater (8) and a boiler feed water heater (9); an outlet of the bag-type dust collector (4) is connected with the flue gas heat collector (5), a waterway outlet (5a) of the flue gas heat collector (5) is respectively connected with the wet slag drying system (6), the primary air heater (7), the secondary air heater (8) and the boiler feed water heater (9) through four branches, and return water is connected with the flue gas heat collector (5) through a circulating pipe (24). The waste heat recycling device has the advantages that waste heat generated by hazardous waste incineration is effectively recycled, and the hazardous waste disposal cost is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of hazardous waste incineration technology, and in particular relates to an energy-saving device for treating flue gas from hazardous waste incineration. Background Technology

[0002] In the field of hazardous waste incineration, rotary kiln incineration is a commonly used disposal technology. Hazardous waste produces incineration residue in the secondary combustion chamber. Typically, this residue enters a wet slag remover through the hopper inlet at the bottom of the secondary combustion chamber. Cooling water in the slag remover rapidly lowers the residue temperature to below 100°C, and the residue is automatically discharged via a scraper slag remover. The wet slag removal system has excellent cooling performance and, due to its water seal system, effectively prevents flue gas leakage.

[0003] However, since incineration residue is hazardous waste, its disposal cost is high. Furthermore, the residue after passing through a wet scrubbing machine has a moisture content of 30-40%, increasing its weight and further raising disposal costs. On the other hand, in existing hazardous waste incineration flue gas treatment systems, the outlet temperature of baghouse dust collectors is generally 160-180℃. A precooler is typically installed before the wet desulfurization tower to lower the temperature to 70℃. The heat difference in between is not utilized, and the flue gas needs to be reheated after desulfurization, resulting in high energy consumption and wasted energy. Utility Model Content

[0004] The purpose of this invention is to solve the problems of high cost, high energy consumption and inability to recover and utilize energy in the treatment of flue gas in existing hazardous waste incineration. It provides an energy-saving device for treating flue gas from hazardous waste incineration, which can effectively recover and utilize the waste heat from hazardous waste incineration, save energy and reduce emissions, reduce the cost of hazardous waste disposal, and improve economic benefits.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An energy-saving device for treating flue gas from hazardous waste incineration includes a hazardous waste treatment system and an energy recycling system that work together. The hazardous waste treatment system includes a rotary kiln, a secondary combustion chamber, a waste heat boiler, a dry desulfurization system, and a bag filter connected in sequence. The energy recycling system includes a flue gas heat exchanger, a wet slag drying system, a primary air heater, a secondary air heater, and a boiler feedwater heater. The primary air heater is connected to the rotary kiln via a first pipe, the secondary air heater is connected to the secondary combustion chamber via a second pipe, and the boiler feedwater heater is connected to the waste heat boiler via a third pipe.

[0007] The outlet of the bag filter is connected to the flue gas heat exchanger. The flue gas heat exchanger is equipped with a water outlet, a gas outlet and a circulation inlet. The gas outlet is connected to the wet desulfurization and flue gas emission system through pipe four, and the water outlet is connected to the circulation pump through pipe five.

[0008] The slag outlet of the secondary combustion chamber is connected to the wet slag remover, the slag outlet of the wet slag remover is connected to the wet slag drying system, and the wet slag drying system is then connected to the dry slag bin via pipe six.

[0009] Pipeline 5 is connected to four parallel branches: branch 1, branch 2, branch 3, and branch 4. Branch 1 is connected to the wet slag drying system, branch 2 is connected to the primary air heater, branch 3 is connected to the secondary air heater, and branch 4 is connected to the boiler feedwater heater. The circulating water outlet of the primary air heater, secondary air heater, boiler feedwater heater, and wet slag drying system is then connected to the circulating inlet of the flue gas heat exchanger through a circulating pipe.

[0010] Furthermore, a regulating valve is connected to the branch line 1. The high-temperature circulating water heated by the flue gas heat exchanger enters the circulating pump and is pumped into the wet slag drying system after the opening is adjusted by the regulating valve 1. A moisture content monitor is connected to the pipeline 6. The opening size is calculated by the moisture content monitor after collecting data.

[0011] Furthermore, a regulating valve is connected to the second branch. The high-temperature circulating water heated by the flue gas heat exchanger enters the circulating pump and is pumped into the primary air heater after the opening is adjusted by the regulating valve. A first temperature monitoring instrument is connected to the first pipeline, and the opening size is calculated by the data collected by the first temperature monitoring instrument.

[0012] Furthermore, a regulating valve is connected to the third branch. The high-temperature circulating water heated by the flue gas heat exchanger enters the circulating pump and enters the secondary air heater after the opening is adjusted by the regulating valve. A second temperature monitoring instrument is connected to the second pipeline, and the opening size is calculated by the second temperature monitoring instrument after collecting data.

[0013] Furthermore, a regulating valve is connected to the fourth branch. The high-temperature circulating water heated by the flue gas heat exchanger enters the circulating pump and is pumped into the boiler feedwater heater after the opening is adjusted by the regulating valve. A third temperature monitoring instrument is connected to the third pipeline, and the opening size is calculated by the data collected by the third temperature monitoring instrument.

[0014] Furthermore, a pressure regulating tank is connected to the fifth pipeline. The pressure regulating tank is located in front of the circulating pump to dynamically replenish water to the circulating water circuit and maintain the stability of the pipeline pressure.

[0015] Furthermore, a fourth temperature monitoring instrument is connected to the fourth pipe.

[0016] Furthermore, the temperature of the incineration residue in the wet slag drying system is approximately 800~900℃, and the slag discharged from the wet slag remover enters the wet slag drying system.

[0017] In the technical solution of this utility model, by adding an energy-saving system, the moisture content of the incineration residue is reduced to below 4%, thereby reducing the cost of hazardous waste disposal. At the same time, the high-temperature flue gas after bag filter dust collection is utilized for waste heat utilization. All the heat required by the wet residue drying system comes from the heat exchanger. The excess heat can also be supplied to the primary air and secondary air heating systems and the boiler feedwater deoxygenation system, which greatly saves external heat sources, improves efficiency and reduces the overall system disposal cost. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the energy-saving device for treating hazardous waste incineration flue gas according to this utility model. Detailed Implementation

[0019] Example

[0020] To make this utility model clearer, the following description, in conjunction with the accompanying drawings, further illustrates an energy-saving device for treating flue gas from hazardous waste incineration. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this utility model.

[0021] See Figure 1 An energy-saving device for treating flue gas from hazardous waste incineration, comprising a hazardous waste treatment system and an energy recycling system working in tandem, characterized in that:

[0022] The hazardous waste treatment system includes a rotary kiln 1, a secondary combustion chamber 2, a waste heat boiler 3, a dry desulfurization and bag filter 4 connected in sequence. The energy recycling system includes a flue gas heat exchanger 5, a wet slag drying system 6, a primary air heater 7, a secondary air heater 8, and a boiler feedwater heater 9. The primary air heater 7 is connected to the rotary kiln 1 through pipe 10, the secondary air heater 8 is connected to the secondary combustion chamber 2 through pipe 21, and the boiler feedwater heater 9 is connected to the waste heat boiler 3 through pipe 312.

[0023] The outlet of the bag filter 4 is connected to the flue gas heat exchanger 5. The flue gas heat exchanger 5 is provided with a water outlet 5a, a gas outlet 5b and a circulation inlet 5c. The gas outlet 5b is connected to the wet desulfurization and flue gas emission system 14 through pipe 13. The water outlet 5a is connected to the circulation pump 16 through pipe 15.

[0024] The slag outlet of the secondary combustion chamber 2 is connected to the wet slag remover 17, the slag outlet of the wet slag remover 17 is connected to the wet slag drying system 6, and the wet slag drying system 6 is then connected to the dry slag bin 19 through pipe 18.

[0025] Pipeline 515 is connected to four parallel branches: branch 120, branch 21, branch 32, and branch 423. Branch 120 is connected to the wet slag drying system 6, branch 21 is connected to the primary air heater 7, branch 32 is connected to the secondary air heater 8, and branch 423 is connected to the boiler feedwater heater 9. The circulating water outlet of the primary air heater 7, secondary air heater 8, boiler feedwater heater 9, and wet slag drying system 6 is then connected to the circulating inlet 5c of the flue gas heat exchanger 5 via the circulating pipe 24.

[0026] A regulating valve 25 is connected to branch 120. The high-temperature circulating water heated by flue gas heat exchanger 5 enters the circulating pump 16 and is pumped into the wet slag drying system 6 after the opening is adjusted by regulating valve 25. A moisture content monitor 29 is connected to pipeline 618. The opening size is calculated by collecting data from the moisture content monitor 29.

[0027] Branch 21 is connected to regulating valve 26. The high-temperature circulating water heated by flue gas heat exchanger 5 enters the circulating pump 16 and is pumped into the primary air heater 7 after the opening is adjusted by regulating valve 26. Pipe 10 is connected to the first temperature monitor 30. The opening size is calculated by the first temperature monitor 30 after collecting data.

[0028] Branch line 22 is connected to regulating valve 27. The high-temperature circulating water heated by flue gas heat exchanger 5 enters the circulating pump 16 and enters the secondary air heater 8 after the opening is adjusted by regulating valve 27. Pipe 2 11 is connected to a second temperature monitor 31. The opening size is calculated by the second temperature monitor 31 after collecting data.

[0029] Branch line 4 23 is connected to regulating valve 4 28. The high-temperature circulating water heated by flue gas heat exchanger 5 enters the circulating pump 16 and is pumped into the boiler feedwater heater 9 after the opening is adjusted by regulating valve 4 28. Pipeline 3 12 is connected to the third temperature monitoring instrument 32. The opening size is calculated by collecting data from the third temperature monitoring instrument 32.

[0030] In this embodiment, a pressure tank 34 is connected to the pipeline 15. The pressure tank 34 is located in front of the circulating pump 16 to dynamically replenish water to the circulating water circuit and maintain the stability of the pipeline pressure.

[0031] In actual use, the high-temperature flue gas generated by the rotary kiln 1 and the secondary combustion chamber 2 is cooled by the waste heat boiler 3 and enters the dry desulfurization and bag filter 4. The high-temperature flue gas generated by the bag filter 4 enters the flue gas heat exchanger 5. The flue gas heat exchanger 5 is divided into water and gas paths. One path heats the circulating water and enters the circulating pump 16. The other path of flue gas enters the wet desulfurization and flue gas emission system 14 after passing through the fourth temperature monitoring instrument 33 and then meets the emission standards.

[0032] When the hazardous waste incineration line is operating normally, the wet slag drying system 6 operates continuously, and the temperature of the incineration residue is about 800~900℃. The slag discharged from the wet slag remover 17 enters the wet slag drying system 6.

[0033] During energy recovery and utilization, the high-temperature circulating water in the circulating pump 16 is pumped through branch 20 to the wet slag drying system 6 to dry the wet slag. The cooled circulating water then enters the flue gas heat exchanger 5 for heat exchange. Excess hot circulating water is used to heat other equipment through branches. Branch 21 enters the primary air heater 7 after the opening is adjusted by regulating valve 26. Branch 32 enters the secondary air heater 8 after the opening is adjusted by regulating valve 27. Branch 423 enters the boiler feedwater heater 9 after the opening is adjusted by regulating valve 28. The circulating water from the four branches is collected by the circulating pipe 24 and returned to the flue gas heat exchanger 5 for recirculation and heating. The pressure tank 34 dynamically replenishes water to ensure stable pipeline pressure.

[0034] In this embodiment, a 70t / d hazardous waste incineration system is used as an example for analysis. The table below shows the specific parameters of each device in the treatment process:

[0035]

[0036] This invention utilizes a flue gas heat exchanger to recover waste heat from flue gas. The recovered heat is used to dry wet slag, heat primary and secondary air, and boiler feedwater, significantly increasing the combustion temperature of the hazardous waste rotary kiln and secondary combustion chamber, while simultaneously reducing the steam consumption of the deaerator in the waste heat boiler system. The energy-saving system incorporates a flue gas heat exchanger between the bag filter and the wet acid removal system. Circulating water is heated by the flue gas heat exchanger to obtain high-temperature circulating water, which sequentially flows into the wet slag drying system, primary air heater, secondary air heater, and feedwater heater to heat the materials produced in the hazardous waste incineration line, thus achieving heat recovery and utilization. This energy-saving device can increase the temperature of the rotary kiln and secondary combustion chamber in the hazardous waste incineration system, reduce auxiliary fuel consumption, decrease steam consumption of the deaerator in the waste heat boiler system, significantly reduce bottom ash volume, and reduce bottom ash disposal costs. It is of great significance for improving the economic efficiency of enterprises and can achieve good social benefits.

[0037] In addition to the embodiments described above, this utility model may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by this utility model.

Claims

1. An energy-saving device for hazardous waste incineration flue gas treatment, comprising a hazardous waste treatment system and an energy recycling system that cooperate with each other, characterized in that: the hazardous waste treatment system comprises a rotary kiln (1), a secondary combustion chamber (2), a waste heat boiler (3), a dry deacidification and bag dust collector (4) connected in sequence, and the energy recycling system comprises a flue gas heat exchanger (5), a wet slag drying system (6), a primary air heater (7), a secondary air heater (8) and a boiler feed water heater (9); the primary air heater (7) is connected with the rotary kiln (1) through a pipeline I (10), the secondary air heater (8) is connected with the secondary combustion chamber (2) through a pipeline II (11), and the boiler feed water heater (9) is connected with the waste heat boiler (3) through a pipeline III (12); the outlet of the bag dust collector (4) is connected with the flue gas heat exchanger (5), the flue gas heat exchanger (5) is provided with a water outlet (5a), a gas outlet (5b) and a circulating inlet (5c), the gas outlet (5b) is connected with a wet deacidification and flue gas emission system (14) through a pipeline IV (13), and the water outlet (5a) is connected with a circulating pump (16) through a pipeline V (15); the slag outlet of the secondary combustion chamber (2) is connected with a wet slag extractor (17), the slag outlet of the wet slag extractor (17) is connected with the wet slag drying system (6), and the wet slag drying system (6) is further connected with a dry slag bin (19) through a pipeline VI (18); four parallel branch pipes, i.e. a branch pipe I (20), a branch pipe II (21), a branch pipe III (22) and a branch pipe IV (23) are connected with the pipeline V (15) respectively, the branch pipe I (20) is connected with the wet slag drying system (6), the branch pipe II (21) is connected with the primary air heater (7), the branch pipe III (22) is connected with the secondary air heater (8), and the branch pipe IV (23) is connected with the boiler feed water heater (9); the circulating water outlet of the primary air heater (7), the secondary air heater (8), the boiler feed water heater (9) and the wet slag drying system (6) is connected with the circulating inlet (5c) of the flue gas heat exchanger (5) through a circulating pipe (24).

2. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1, characterized in that: the branch pipe I (20) is connected with a regulating valve I (25), the high-temperature circulating water heated by the flue gas heat exchanger (5) enters the circulating pump (16) and is pumped into the wet slag drying system (6) after the opening degree is adjusted by the regulating valve I (25), the pipeline VI (18) is connected with a moisture content monitor (29), and the opening degree is calculated according to the data collected by the moisture content monitor (29).

3. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1 or 2, characterized in that: the branch pipe II (21) is connected with a regulating valve II (26), the high-temperature circulating water heated by the flue gas heat exchanger (5) enters the circulating pump (16) and is pumped into the primary air heater (7) after the opening degree is adjusted by the regulating valve II (26), the pipeline I (10) is connected with a first temperature monitor (30), and the opening degree is calculated according to the data collected by the first temperature monitor (30).

4. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1 or 2, characterized in that: ​ ​ ​ ​ ​ ​ The branch three (22) is connected with regulating valve three (27), the high temperature circulating water after heating by flue gas heat exchanger (5) enters circulating pump (16), and then enters secondary air heater (8) after regulating opening by regulating valve three (27), the pipeline two (11) is connected with second temperature monitor (31), and the opening size is calculated after collecting data by second temperature monitor (31).

5. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1 or 2, characterized in that: The branch four (23) is connected with regulating valve four (28), the high temperature circulating water after heating by flue gas heat exchanger (5) enters circulating pump (16), and then is pumped into boiler feed water heater (9) after regulating opening by regulating valve four (28), the pipeline three (12) is connected with third temperature monitor (32), and the opening size is calculated after collecting data by third temperature monitor (32).

6. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1 or 2, characterized in that: The pipeline five is connected with constant pressure tank, and the constant pressure tank is arranged in the front part of the circulating pump.

7. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1 or 2, characterized in that: The pipeline four (13) is connected with fourth temperature monitor (33).

8. The energy-saving device for hazardous waste incineration flue gas treatment according to claim 1 or 2, characterized in that: The incineration residue temperature of the wet residue drying system (6) is about 800-900 ℃, and the wet residue drying system (6) is entered by the wet residue from the wet residue extractor (17).

Images