Radioactive biological waste microwave incinerator tail gas treatment device and method

Abstract

This invention discloses a device and method for treating exhaust gas from a microwave ashing furnace for radioactive biological waste. The device includes a high-temperature filter, a radionuclide adsorption device, and a catalytic combustion device connected in sequence. The high-temperature filter contains a metal filter bag filled with a first metal fiber blanket filter felt. An oil sludge discharge port is located at the bottom of the high-temperature filter. Exhaust gas from the microwave ashing furnace for radioactive biological waste is introduced through the inlet of the high-temperature filter. The radionuclide adsorption device is filled with a C14 adsorbent, and the catalytic combustion device is filled with a catalyst. A heating structure is arranged around the catalyst. The catalytic combustion device is connected to an induced draft fan via an exhaust gas discharge pipe, which is equipped with a mixing pipe. Through the treatment of each subsystem, C14 in the exhaust gas can be effectively removed, ensuring that the exhaust gas meets emission requirements.

Description

Technical Field

[0001] This invention relates to the field of radioactive biological incineration tail gas treatment technology, and in particular to a device and method for treating tail gas from a microwave ashing furnace for radioactive biological waste. Background Technology

[0002] The exhaust gas purification system is a crucial component of the main process system in nuclear facilities. Its function is to control the concentration of pollutants in the gaseous effluent emitted from the main incineration process within the range specified in the "Standard for Pollution Control of Hazardous Waste Incineration," ensuring that the radioactivity concentration meets management targets. Since the exhaust gas purification system involves multiple chemical operation units, and more than half of the equipment in the main process system belongs to this system, it is a key factor in determining the stable, efficient, clean, and safe operation of the entire nuclear facility. Currently, the main exhaust gas treatment process used in the facility is "flue gas cooling + radionuclide removal via filter + wet desulfurization." Even after the exhaust gas is rapidly cooled, it passes through bag filters for dust removal, then through an alkali tower to absorb SO2, and finally through a high-efficiency filter. This process ensures that the exhaust gas from waste incineration complies with the "Standard for Pollution Control of Hazardous Waste Incineration."

[0003] In accordance with the requirements of (GB18484-2001), the exhaust gas must meet the emission standards.

[0004] Currently, the main process used in exhaust gas treatment systems is "flue gas cooling + filter removal of radionuclides + dry / wet desulfurization," which generally does not include a process for removing carbon-14 (C14) radionuclides. However, the proportion of biological waste in radioactive waste is constantly increasing, and most of this biological waste remains in a frozen storage state due to the lack of suitable exhaust gas treatment processes. Furthermore, current exhaust gas treatment systems that directly treat exhaust gas from biological waste can cause filter clogging or result in substandard exhaust gas emissions. Therefore, there is an urgent need to develop an exhaust gas treatment system specifically for biological waste to treat the exhaust gas, remove C14, and ensure that the exhaust gas meets emission standards. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a device and method for treating the exhaust gas from a microwave ashing furnace for radioactive biological waste.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a device for treating the exhaust gas from a microwave ashing furnace for radioactive biological waste, characterized in that it comprises a high-temperature filter, a radionuclide adsorption device, and a catalytic combustion device connected in sequence. The high-temperature filter contains a metal filter bag filled with a first metal fiber blanket filter felt. An oil sludge discharge port is provided at the bottom of the high-temperature filter. The exhaust gas from the microwave ashing furnace for radioactive biological waste is introduced from the inlet end of the high-temperature filter. The radionuclide adsorption device is filled with C14 adsorbent. The catalytic combustion device is filled with a catalyst. A heating structure is provided around the catalyst. The catalytic combustion device is connected to an induced draft fan through an exhaust gas discharge pipe. A mixing pipe is provided on the exhaust gas discharge pipe.

[0008] Furthermore, a second metal fiber blanket filter felt is provided in the gap between the metal filter bags.

[0009] Furthermore, a differential pressure gauge is installed on the high-temperature filter.

[0010] Furthermore, the radionuclide adsorption device is equipped with multiple layers of sieves, and the C14 adsorbent is spread evenly on the sieves.

[0011] Furthermore, the screen is arranged in three layers from top to bottom.

[0012] Furthermore, the radionuclide adsorption device is provided with an inspection port.

[0013] Furthermore, the catalytic combustion device is equipped with a first temperature gauge.

[0014] Furthermore, a second temperature gauge is installed on the exhaust pipe.

[0015] Furthermore, the catalytic combustion device has a vertical structure, and the exhaust pipe is located at the bottom of the catalytic combustion device.

[0016] Secondly, the present invention provides a method for treating the exhaust gas from a microwave ashing furnace for radioactive biological waste, characterized in that, using the device described in the first aspect, the method includes the following steps: the exhaust gas from the microwave ashing furnace for radioactive biological waste is introduced from the inlet end, and grease and hair in the exhaust gas are adsorbed and filtered out in a high-temperature filter, then enters a radionuclide adsorption device, where a C14 adsorbent adsorbs and removes C14 radionuclides from the exhaust gas, then enters a catalytic combustion device, where unburned biological fibers in the exhaust gas are catalytically combusted, and finally, the exhaust gas is mixed with air in the exhaust gas discharge pipe and then cooled before being discharged.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) The present invention provides a treatment device and process for the tail gas of microwave ashing furnace for radioactive biological waste. Through the treatment of each subsystem, C14 in the tail gas can be effectively removed so that the tail gas meets the emission requirements.

[0019] (2) The present invention uses a more environmentally friendly process to treat exhaust gas. It uses a dry treatment process that is currently less common to adsorb C14, which does not generate secondary waste and saves energy. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device structure of the present invention;

[0021] Wherein: 1-High temperature filter, 2-Nucleotide adsorption device, 3-Catalytic combustion device, 4-Exhaust fan, 11-Metal filter bag, 12-Differential pressure gauge, 13-Oil sludge discharge port, 14-Air inlet, 21-Screen, 31-Catalyst, 32-Heating structure, 33-Tail exhaust pipe, 34-Mixing pipe, 35-First temperature gauge, 36-Second temperature gauge. Detailed Implementation

[0022] To enhance understanding of the present invention, we will now describe it in further detail with reference to the accompanying drawings. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0023] Figure 1 An embodiment of a microwave ashing furnace exhaust gas treatment device for radioactive biological waste is shown, comprising a high-temperature filter 1, a radionuclide adsorption device 2, and a catalytic combustion device 3 connected in sequence. This device uses a dry method to absorb C14 radionuclides in the exhaust gas, reducing the generation of secondary waste.

[0024] The high-temperature filter 1 is equipped with a metal filter bag 11, which is filled with a first metal fiber blanket filter felt. A second metal fiber blanket filter felt is placed in the gap between the metal filter bags 11. The bottom of the high-temperature filter 1 is equipped with an oil sludge discharge port 13. The high-temperature filter 1 is equipped with a differential pressure gauge 12. The exhaust gas from the microwave ashing furnace for radioactive biological waste is introduced from the air inlet 14 of the high-temperature filter 1.

[0025] Biological waste typically contains large amounts of grease, hair, etc., which, if not completely burned during treatment, can clog subsequent radionuclide adsorption and catalytic combustion subsystems. Therefore, a high-temperature filter 1 is installed first in the exhaust gas treatment system. The main body of the high-temperature filter 1 is a metal shell, with an oil sludge discharge port 13 at the bottom to discharge the oil sludge and other contaminants filtered out by the high-temperature filter 1. The exhaust gas enters the high-temperature filter 1 from the inlet end 14, passes through the metal filter bag 11, and then enters the radionuclide adsorption device 2 for treatment.

[0026] The radionuclide adsorption device 2 contains three layers of screens 21, with C14 adsorbent spread evenly on the screens 21. The exhaust gas after passing through the high-temperature filter 1 needs radionuclide adsorption treatment. C14 is a relatively common and difficult-to-treat radionuclide found in biological waste, and current research on C14 adsorption treatment is limited. This process employs a multi-stage adsorption process. The outer shell of the radionuclide adsorption device 2 is a metal cylindrical structure, containing three layers of screens 21. C14 adsorbent is spread evenly on the screens 21, allowing the exhaust gas to undergo multi-stage high-efficiency adsorption, achieving an adsorption efficiency of over 99%. Inspection ports are provided at the location of each adsorbent layer for easy replacement after adsorbent failure. Furthermore, the dry treatment of radionuclides does not generate secondary waste, contributing to energy conservation and emission reduction. After three stages of adsorption, the C14 radionuclide in the exhaust gas is removed, ensuring the exhaust gas meets emission requirements.

[0027] The catalytic combustion device 3 is filled with a catalyst 31, and a heating structure 32 is arranged around the catalyst 31. A first thermometer 35 is installed on the catalytic combustion device 3. The catalytic combustion device 3 is connected to an induced draft fan 4 through a tail gas emission pipe 33. A mixing pipe 34 and a second thermometer 36 are installed on the tail gas emission pipe 33. After the tail gas is adsorbed by the radionuclide adsorption device 2, there may be unburned biological fibers in the tail gas. These need to be treated by catalytic combustion. The unburned biological fibers in the tail gas are catalytically combusted, and finally mixed with air in the tail gas emission pipe 33 and cooled before being discharged.

[0028] The above specific embodiments are only for illustrating the technical concept and structural features of the present invention, and are intended to enable those skilled in the art to implement them. However, the above content does not limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit and essence of the present invention should fall within the scope of protection of the present invention.

Claims

1. A device for treating the exhaust gas from a microwave ashing furnace for radioactive biological waste, characterized in that: The device includes a high-temperature filter (1), a radionuclide adsorption device (2), and a catalytic combustion device (3) connected in sequence. The high-temperature filter (1) is equipped with a metal filter bag (11) and is filled with a first metal fiber blanket filter felt. The bottom of the high-temperature filter (1) is equipped with an oil sludge discharge port (13). The exhaust gas from the microwave ashing furnace for radioactive biological waste is introduced from the air inlet (14) of the high-temperature filter (1). The radionuclide adsorption device (2) is filled with C14 adsorbent. The catalytic combustion device (3) is filled with a catalyst (31). A heating structure (32) is provided around the catalyst. The catalytic combustion device (3) is connected to an induced draft fan (4) through an exhaust gas discharge pipe (33). A mixing pipe (34) is provided on the exhaust gas discharge pipe (33). A second metal fiber blanket filter felt is provided in the gap between the metal filter bags (11).

2. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 1, characterized in that: The high-temperature filter (1) is equipped with a differential pressure gauge (12).

3. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 1, characterized in that: The radionuclide adsorption device (2) is equipped with multiple layers of screens (21), and the C14 adsorbent is spread flat on the screens (21).

4. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 3, characterized in that: The screen (21) is arranged in three layers from top to bottom.

5. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 1, characterized in that: The radionuclide adsorption device (2) is equipped with an inspection port.

6. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 1, characterized in that: The catalytic combustion device (3) is equipped with a first temperature gauge (35).

7. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 1, characterized in that: A second thermometer (36) is installed on the exhaust pipe (33).

8. The device for treating the tail gas of a microwave ashing furnace for radioactive biological waste according to claim 1, characterized in that: The catalytic combustion device (3) has a vertical structure, and the exhaust pipe (33) is located at the bottom of the catalytic combustion device (3).

9. A method for treating exhaust gas from a microwave ashing furnace for radioactive biological waste, characterized in that, Using the apparatus according to any one of claims 1-8, the process includes the following steps: the exhaust gas from the microwave ashing furnace for radioactive biological waste is introduced from the inlet end (14), and the grease and hair in the exhaust gas are adsorbed and filtered out in the high-temperature filter (1). Then it enters the radionuclide adsorption device (2), where the C14 adsorbent adsorbs and removes the C14 radionuclide in the exhaust gas. Next, it enters the catalytic combustion device (3), where the unburned biological fibers in the exhaust gas are catalytically burned. Finally, the exhaust gas is mixed with air in the exhaust gas discharge pipe (33) and then cooled and discharged.

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