Waste activated carbon regeneration tail gas secondary combustion device

Abstract

The utility model provides a waste activated carbon regeneration tail gas secondary combustion device, and relates to the technical field of waste activated carbon regeneration. The waste activated carbon regeneration tail gas secondary combustion device comprises a secondary combustion chamber, a combustible gas supply module, a secondary combustion chamber outlet flue, a recycled flue gas flue, a discharged flue gas flue, an oxygen-enriched air supply module and a combustion-supporting air supply module. The flue gas recycling flue and the flue gas discharging flue are both connected with the secondary combustion chamber outlet flue, so that part of flue gas is discharged, part of flue gas is recycled, the flue gas recycling flue and the oxygen-enriched air supply module are both connected with the combustion-supporting air supply module, the combustion-supporting air supply module and the combustible gas supply module are both connected with the secondary combustion chamber, and the combustible gas supply module is connected with the secondary combustion chamber. The oxygen-enriched air and the recycled flue gas are mixed and then enter the secondary combustion chamber through the combustion-supporting air supply module, direct utilization of high-temperature flue gas heat is achieved, the two streams of gas are directly mixed instead of dividing wall type heat exchange through a heat exchanger, and the utilization rate of flue gas waste heat is high.

Description

Technical Field

[0001] This utility model relates to the field of waste activated carbon regeneration technology, and in particular to a waste activated carbon regeneration tail gas secondary combustion device. Background Technology

[0002] In the waste activated carbon regeneration process, the secondary combustion chamber is located at the rear end of the rotary kiln. Its main function is to ensure the complete combustion of the regeneration tail gas desorbed from the rotary kiln, eliminating harmful substances in the tail gas. According to the relevant requirements of the "Standard for Pollution Control of Hazardous Waste Incineration" (GB18484-2020), the flue gas temperature in the secondary combustion chamber should not be lower than 1100℃, and the flue gas residence time should be greater than or equal to 2 seconds. At this temperature, dioxins synthesized in the previous stage can also be completely decomposed, and harmful substances in the tail gas are fully oxidized to form CO. 2 The presence of water vapor and a flue gas residence time of 2 seconds or more ensures a high decomposition rate.

[0003] In the conventional process, a waste heat boiler is installed at the high-temperature flue gas outlet of the secondary combustion chamber to recover a portion of the flue gas waste heat to reduce the flue gas temperature, while generating steam for the final activation and regeneration of waste activated carbon in the rotary kiln; then the flue gas enters the quench tower, where the flue gas temperature drops to below 200°C within 1 second, reducing the residence time of the flue gas at 200~500°C and reducing the formation of dioxins from the source.

[0004] To better utilize the heat from the high-temperature flue gas at the outlet of the secondary combustion chamber, a partitioned heat exchange is typically used to transfer the combustion air, thereby increasing the combustion air temperature and saving some natural gas consumption. However, due to limitations in heat exchange efficiency, the heat from the high-temperature flue gas at the outlet of the secondary combustion chamber is not fully utilized, resulting in some energy waste. This application addresses these shortcomings. Utility Model Content

[0005] The purpose of this invention is to provide a secondary combustion device for waste activated carbon regeneration tail gas, which can make full use of its own flue gas waste heat, reduce natural gas consumption, and solve the problem that the heat of high-temperature flue gas cannot be fully utilized.

[0006] To address the aforementioned problems, this utility model provides a secondary combustion device for waste activated carbon regeneration tail gas, comprising a secondary combustion chamber, a combustible gas supply module, a secondary combustion chamber outlet flue, a reused flue gas flue, an exhaust flue, an oxygen-enriched air supply module, and an auxiliary combustion air supply module. The reused flue gas flue and the exhaust flue are both connected to the secondary combustion chamber outlet flue, allowing some flue gas to be discharged and some to be reused. The reused flue gas flue and the oxygen-enriched air supply module are both connected to the auxiliary combustion air supply module. The auxiliary combustion air supply module and the combustible gas supply module are both connected to the secondary combustion chamber. After mixing, the oxygen-enriched air and the reused flue gas enter the secondary combustion chamber via the auxiliary combustion air supply module. The secondary combustion chamber is connected to a rotary kiln, enabling direct utilization of the heat from the high-temperature flue gas. The two gases are directly mixed, rather than through a heat exchanger, resulting in a higher utilization rate of waste heat from the flue gas.

[0007] According to one embodiment of the present invention, the waste activated carbon regeneration tail gas secondary combustion device further includes a sensor module, and the sensor module further includes a secondary combustion chamber temperature measurement module. The secondary combustion chamber temperature measurement module is used to measure the highest flue gas temperature at the center of the secondary combustion chamber and control it to ensure that the flue gas temperature is greater than or equal to 1100℃. The secondary combustion chamber temperature measurement module can be an infrared thermometer.

[0008] According to one embodiment of the present invention, the sensor module further includes a combustion air oxygen concentration sensor for measuring the oxygen concentration of the combustion air and ensuring that the oxygen concentration of the combustion air is between 27% and 30%.

[0009] According to one embodiment of the present invention, the sensor module further includes an oxygen-enriched air oxygen concentration sensor, used to measure the oxygen concentration at the outlet of the oxygen-enriched air supply module and control the oxygen concentration between 39% and 2%.

[0010] According to one embodiment of the present invention, the sensor module further includes a reclaimed flue gas oxygen concentration sensor to control the oxygen concentration at around 6% to 10% to ensure that the regenerated exhaust gas is fully combusted.

[0011] According to one embodiment of the present invention, the oxygen-enriched air supply module includes a membrane oxygen-enriching device. The membrane oxygen-enriching device can preferably be a skid-mounted standard module of model ZOE12-1K. Under certain operating conditions, when the pressure of the oxygen-enriched gas produced by a single standard module is 300 kPa, the oxygen-enriched flow rate is about 550 Nm3 / h and the oxygen-enriched concentration reaches 39%.

[0012] According to one embodiment of the present invention, the waste activated carbon regeneration tail gas secondary combustion device further includes a control module, wherein the sensor module is electrically connected to the control module, and the control module is used to control the oxygen concentration of the combustion air.

[0013] According to one embodiment of the present invention, the control module includes a fan assembly and a valve body assembly. The fan assembly may be a variable frequency fan, used to control the amount of flue gas entering the reuse flue gas duct. The valve body assembly may be an overflow valve, used to control the amount of gas supplied to the membrane oxygen enrichment device.

[0014] According to one embodiment of the present invention, the waste activated carbon regeneration tail gas secondary combustion device further includes an emergency exhaust chimney, which is connected to the secondary combustion chamber and is used for rapid exhaust of smoke in emergency situations.

[0015] According to one embodiment of the present invention, the secondary combustion chamber is connected to the slag discharge machine.

[0016] The beneficial effects of this utility model are that this solution is applicable to the regeneration process of waste activated carbon. By directly reusing the high-temperature flue gas from the outlet of the secondary combustion chamber and mixing it with oxygen-enriched air to form combustion air that enters the secondary combustion chamber, the temperature of the combustion air can be increased to the maximum extent. Moreover, since the two gases are directly mixed, rather than through heat exchanger walls, the waste heat of the flue gas can be fully utilized, achieving a high utilization rate. Combined with the optimal oxygen concentration, the natural gas consumption of the secondary combustion chamber is effectively reduced, the natural gas cost is lowered, and thus the regeneration cost of waste activated carbon is reduced. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 A schematic diagram of the overall structure of a secondary combustion device for waste activated carbon regeneration tail gas;

[0019] Figure 2 This is a schematic diagram of the gas flow in the secondary combustion chamber;

[0020] Figure 3 This is a flowchart of the control module. Detailed Implementation

[0021] The following description is only intended to disclose the present invention so that those skilled in the art can implement it. The embodiments in the following description are merely examples, and those skilled in the art will conceive of other obvious modifications. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other solutions that do not depart from the spirit and scope of the present invention.

[0022] Example 1:

[0023] A secondary combustion device for waste activated carbon regeneration tail gas includes a secondary combustion chamber 1, a secondary combustion chamber outlet flue 2, a rotary kiln 3, a slag remover 4, an emergency exhaust chimney 5, a combustible gas supply module 6, an oxygen-enriched air supply module 7, a reuse flue gas duct 8, an external exhaust flue gas duct 9, and an auxiliary combustion air supply module 10.

[0024] like Figure 1 The secondary combustion chamber 1 is connected to the rotary kiln 3, the slag remover 4, the emergency exhaust chimney 5, and the secondary combustion chamber outlet flue 2. The secondary combustion chamber outlet flue 2 is divided into two paths: one for reusable flue gas and the other for exhaust flue gas, which is treated according to the conventional process. The reusable flue gas and the exhaust flue gas flow through the reusable flue gas flue 8 and the exhaust flue gas flue 9, respectively. The reusable flue gas is mixed with oxygen-enriched air to form combustion air. The oxygen-enriched air is provided by the oxygen-enriched air supply module 7, which includes a membrane oxygen-enriching device. The combustion air supply module 10 can be a pipeline, and the combustion air is transported to the secondary combustion chamber 1 by the combustion air supply module 10.

[0025] The combustible gas supply module 6 is used to supply natural gas to the secondary combustion chamber 1.

[0026] In this embodiment, the oxygen-enriched air is obtained by filtration of compressed air produced by the factory's compressed air station, followed by membrane separation in a membrane oxygen-enrichment device to obtain high-pressure oxygen-enriched air with an oxygen concentration of approximately 39%. The resulting nitrogen-enriched gas and excess gas are utilized or stored by other process gas devices. The oxygen content of the recycled flue gas at the outlet of the secondary combustion chamber 1 is generally around 6-10%. The oxygen concentration of the combustion air formed by mixing the two gases needs to be controlled between 27-30%. This oxygen concentration is more effective in increasing the combustion temperature. A higher oxygen concentration will have a relatively weaker effect on increasing the combustion temperature; while a lower oxygen concentration means an increase in nitrogen content, which will correspondingly increase the amount of combustion products generated. The oxygen concentration of the combustion air is controlled by adjusting the amount of recycled flue gas.

[0027] Secondly, since the oxygen-enriched air is produced through a membrane oxygen-enrichment device, the gas temperature is generally between 45 and 55°C, while the flue gas recycled at the outlet of the secondary combustion chamber is generally between 1100°C. Because the two gases are directly mixed, rather than through heat exchangers, the utilization rate of the flue gas waste heat is the highest.

[0028] According to the principle of heat balance in the combustion process, when heat input and output are equal, the recycled flue gas, as a combustion product, reaches a relatively stable combustion temperature of 1100℃. The heat input mainly consists of the calorific value (lower heating value) Q of the natural gas. dw The physical heat Q from the combustion air a The physical heat Q from natural gas f When the temperature of the combustion air increases, the resulting physical heat Q... a Increase, the physical heat Q from natural gas f If the calorific value (lower heating value) of the natural gas remains unchanged, then the required calorific value (lower heating value) of the natural gas is Q. dw This can be reduced accordingly, meaning that natural gas consumption will decrease.

[0029] The heat expenditure mainly consists of the physical heat Q of the combustion product flue gas. p The heat Q transferred from the flue gas to surrounding objects 传 Incomplete combustion heat loss Q 不 The heat Q consumed in the thermal dissociation reaction of a certain gas in flue gas at high temperature. li The meaning of the physical heat of flue gas, Q. p= V p *C PP *T p V p This represents the total volume of reused flue gas and exhaust gas. The combustion temperature T is also included. p The temperature remains constant at 1100℃. Since the oxygen concentration in the combustion air is between 27% and 30%, higher than the 21% oxygen concentration in conventional air, this means that the proportion of triatomic gases CO2 and H2O in the flue gas is slightly increased, thus increasing the specific heat capacity C. PP There was also a slight increase; at the same time, the reduction in nitrogen content lowered NOx emissions, i.e., V p Some reduction. Therefore, the physical heat Q of the flue gas p The basic situation remains unchanged, meaning that the expenditure of calories has not changed.

[0030] Example 2:

[0031] Based on Example 1, such as Figure 2 , Figure 3 This embodiment also includes a sensor module and a control module. The sensor module further includes a secondary combustion chamber temperature measurement module, a combustion air oxygen concentration sensor, an oxygen-enriched air oxygen concentration sensor, and a recycled flue gas oxygen concentration sensor. Through the cooperation of the control module and sensors, the utilization of waste heat from the secondary combustion chamber can be maximized while the consumption of natural gas can be minimized. Relying on existing control algorithms and other technologies, the reuse of flue gas from the secondary combustion chamber can be achieved, which can significantly improve the reliability of system regulation.

[0032] Specifically, the secondary combustion chamber temperature measurement module is used to measure the highest flue gas temperature at the center of the secondary combustion chamber 1, and control it to ensure that the flue gas temperature is greater than or equal to 1100℃. The secondary combustion chamber temperature measurement module can be an infrared thermometer. The combustion air oxygen concentration sensor is used to measure the oxygen concentration of the combustion air, and ensure that the oxygen concentration of the combustion air is between 27% and 30%. The oxygen-enriched air oxygen concentration sensor is used to measure the oxygen concentration at the outlet of the oxygen-enriched air supply module, and control the oxygen concentration to be between 39% and 2%. The recycled flue gas oxygen concentration sensor is used to control the oxygen concentration to be around 6% to 10%, to ensure that the regenerated exhaust gas is fully combusted.

[0033] The control module includes automatic control equipment and actuators. The automatic control equipment can be a PLC programmable controller or a computer. The actuators include a variable frequency fan for controlling the proportion of reclaimed flue gas entering the reclaimed flue gas duct 8, and an overflow valve for controlling the amount of gas supplied to the membrane oxygen enrichment device. The automatic control equipment can also control the membrane oxygen enrichment device and control the outlet oxygen concentration.

[0034] The exhaust gas from flue 9 is discharged through a waste heat boiler, a quench tower, a bag filter, a primary spray tower, a secondary spray tower, an induced draft fan, and a chimney.

[0035] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been shown and explained in the embodiments. Without departing from the stated principles, the implementation of the present invention may have any variations and modifications.

Claims

1. A waste activated carbon regeneration off-gas secondary combustion device, characterized by: The device comprises a secondary combustion chamber (1), a combustible gas supply module (6), a secondary combustion chamber outlet flue (2), a recycled flue gas flue (8), an exhaust flue gas flue (9), an oxygen-enriched air supply module (7) and a combustion air supply module (10), the recycled flue gas flue (8) and the exhaust flue gas flue (9) are connected with the secondary combustion chamber outlet flue (2), the recycled flue gas flue (8) and the oxygen-enriched air supply module (7) are connected with the combustion air supply module (10), the combustion air supply module (10) and the combustible gas supply module (6) are connected with the secondary combustion chamber (1), and the oxygen-enriched air and the recycled flue gas are mixed and then enter the secondary combustion chamber (1) through the combustion air supply module (10).

2. The waste activated carbon regeneration off-gas secondary combustion device according to claim 1, characterized in that: The waste activated carbon regeneration tail gas secondary combustion device further comprises a sensor module, the sensor module further comprises a secondary combustion chamber temperature measurement module, and the secondary combustion chamber temperature measurement module is used for measuring the highest flue gas temperature at the center position in the secondary combustion chamber (1).

3. The waste activated carbon regeneration off-gas secondary combustion device according to claim 2, characterized in that: The sensor module further comprises a combustion air oxygen concentration sensor.

4. The waste activated carbon regeneration off-gas secondary combustion device according to claim 3, characterized by: The sensor module further comprises an oxygen-enriched air oxygen concentration sensor.

5. The waste activated carbon regeneration off-gas secondary combustion device according to claim 4, characterized by: The sensor module further comprises a recycled flue gas oxygen concentration sensor.

6. The waste activated carbon regeneration off-gas secondary combustion device according to any one of claims 1-5, characterized in that: The oxygen-enriched air supply module (7) comprises a membrane type oxygen-enriched device.

7. The waste activated carbon regeneration off-gas secondary combustion device according to claim 5, characterized in that: The waste activated carbon regeneration tail gas secondary combustion device further comprises a control module, the sensor module is electrically connected with the control module, and the control module is used for controlling the oxygen concentration of the combustion air.

8. The waste activated carbon regeneration off-gas secondary combustion device according to claim 7, characterized in that: The control module comprises a fan assembly and a valve body assembly.

9. The waste activated carbon regeneration off-gas secondary combustion device according to any one of claims 1-5, characterized in that: The waste activated carbon regeneration tail gas secondary combustion device further comprises an emergency exhaust chimney (5), and the emergency exhaust chimney (5) is connected with the secondary combustion chamber (1).

10. The waste activated carbon regeneration off-gas secondary combustion device according to claim 9, characterized by: The secondary combustion chamber (1) is connected with a slagging machine (4).

Images