Treatment system and treatment method for radioactive biological waste

Abstract

The invention provides a treatment system for radioactive biological waste, which comprises a pretreatment unit, an ashing heating unit and a tail gas treatment unit, and is characterized in that the pretreatment unit is configured to perform crushing treatment on the radioactive biological waste and comprises a crushing unit and a conveying unit; the ashing heating unit is configured to perform microwave sterilization and microwave ashing heating on the crushed radioactive biological waste by using a microwave technology; the tail gas treatment unit is configured to treat flue gas generated by the ashing heating unit in the ashing heating process, and the treatment comprises catalytic oxidation, cooling, adsorption and harmless tail gas emission of the flue gas. The invention further provides a method for treating the radioactive biological waste by using the treatment system. The radioactive biological waste can be rapidly and safely treated through the system and the method.

Description

Technical Field

[0001] The present invention relates to the technical field of radioactive waste treatment, and in particular to a treatment system and a treatment method for radioactive biological waste. Background Art

[0002] According to the relevant laws and regulations of my country, a certain number of isotope animal experiments must be conducted in the development of new drugs and research and testing of radioactive isotopes to meet the requirements of various research aspects such as pharmacokinetics. In recent years, due to the rapid development of the industry, animal experiments using radioactive isotopes will generate more and more radioactive biological waste. Relevant research companies and research institutions are facing increasingly severe problems in the treatment of radioactive biological waste. Due to the lack of clear treatment plans, radioactive waste is mostly in a temporary storage state, which poses certain safety risks.

[0003] In addition, the cost of direct disposal of radioactive waste is high.

[0004] According to the existing China Isotope and Radiation Industry Association group standard "Regulations on the Management of 14C-Containing Biological Waste", radioactive biological waste should first be converted into radioactive waste through pretreatment to remove the characteristics of biological waste, and then treated in accordance with the radioactive waste treatment and disposal plan.

[0005] Conventional heating ashing methods use electric heating methods, which have the disadvantages of slow heating rate and long processing time. Therefore, a system and method that can quickly and safely treat radioactive waste is needed. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a treatment system and a treatment method for radioactive biological waste, so as to quickly and safely treat the radioactive biological waste.

[0007] To achieve the above object, in a first aspect of the present invention, a system for treating radioactive biological waste is provided, comprising a pretreatment unit, an ashing and heating unit and a tail gas treatment unit, wherein:

[0008] The pretreatment unit is configured to pulverize the radioactive biological waste, and includes a pulverization unit and a conveying unit. The radioactive biological waste treated by the pretreatment unit is conveyed to the ashing and heating unit through the conveying unit.

[0009] The ashing and heating unit is configured to use microwave technology to perform microwave sterilization and microwave ashing heating on the radioactive biological waste after the pulverization process, and the flue gas generated during the microwave ashing heating process of the ashing and heating unit is transported to the tail gas treatment unit through a pipeline;

[0010] The tail gas treatment unit is configured to treat the flue gas generated by the ashing heating unit during the ashing heating process, and the treatment includes: catalytic oxidation, cooling, adsorption and harmless tail gas emission of the flue gas.

[0011] In an embodiment of the first aspect, the crushing unit includes a motor, a crushing mechanism, and a shell. The shell is provided with a rectangular crushing inlet, and the crushing mechanism is a mechanical crushing tooth.

[0012] In an embodiment of the first aspect, the ashing heating unit comprises a microwave generating unit, an ashing heating cavity, a microwave control unit, a microwave cooling unit and a sensitizer adding unit, wherein:

[0013] The microwave generating unit is configured to generate microwaves to sterilize the radioactive biological waste in the ashing heating cavity and to heat the ashing, and is arranged around the ashing heating cavity;

[0014] The microwave control unit is configured to control the power and switch of the microwave generating unit and monitor the temperature and pressure in the ashing heating cavity to ensure that the operation status of the microwave generating unit is consistent with the microwave ashing heating process;

[0015] The microwave cooling unit includes a water chiller and cooling water pipelines;

[0016] The sensitizer adding unit is arranged before the ashing heating cavity and is used to add microwave sensitizer to the crushed radioactive biological waste transported in the conveying unit to enhance the effect of microwave ashing.

[0017] In the implementation of the first aspect, the chiller maintains cooling water at a specified temperature, and the cooling water pipeline is wound around the microwave generating unit to reduce the temperature of the microwave generating unit during operation, ensuring that the operating temperature of the microwave generating unit is in a normal operating condition during operation.

[0018] In an embodiment of the first aspect, the microwave sensitizer is any one of ferroferric oxide sensitizer, aluminum powder, zinc powder, activated carbon, and graphite powder.

[0019] In an embodiment of the first aspect, the speed at which the conveying unit passes under the sensitizer adding unit depends on the amount of biological waste added, the moving speed of the conveying unit, and the type of microwave sensitizer.

[0020] In an implementation of the first aspect, an ashing heating vessel is arranged in the ashing heating cavity, and the ashing heating vessel is a corundum crucible.

[0021] In the implementation of the first aspect, the tail gas treatment unit includes a catalytic combustion furnace, an air mixing interface, a carbon dioxide adsorber and a negative pressure fan, wherein the catalytic combustion furnace, the air mixing interface, the carbon dioxide adsorber and the negative pressure fan are connected in sequence, wherein:

[0022] The ashing heating chamber is connected to the catalytic combustion furnace through an exhaust gas delivery pipeline;

[0023] The catalytic combustion furnace is configured to decompose organic waste in the flue gas into carbon dioxide and water;

[0024] The air mixing interface is a Y-shaped structure air mixing interface, which has two Y-shaped bifurcations and a straight air mixing pipeline, wherein one Y-shaped bifurcations is connected to the air mixing gas pipeline, and the other Y-shaped bifurcations is connected to the catalytic combustion tail gas exhaust outlet of the catalytic combustion furnace, and the air mixing process is realized in the straight air mixing pipeline behind the air mixing interface with the catalytic combustion tail gas;

[0025] The carbon dioxide adsorber is configured to adsorb carbon dioxide from the exhaust gas using a carbon dioxide solid adsorption method;

[0026] The negative pressure fan is connected to the carbon dioxide adsorber and is configured to discharge the remaining gas adsorbed by the carbon dioxide adsorber out of the system.

[0027] In an embodiment of the first aspect, the catalytic combustion furnace is a regenerative catalytic combustion furnace.

[0028] To achieve the above object, in a second aspect of the present invention, a method for treating radioactive biological waste using the above treatment system is provided, comprising the following steps:

[0029] Pretreatment of radioactive biological waste: Use the crushing unit in the pretreatment unit to crush the biological waste;

[0030] Ashing treatment of radioactive biological waste: the biological waste after pulverization is transported to the pulverization heating unit by using a conveying unit, wherein, before being transported to the pulverization heating cavity in the pulverization heating unit, a microwave sensitizer is added to the pulverized biological waste through a sensitizer adding pipeline of a sensitizer adding unit; in the pulverization heating cavity, microwaves emitted by a microwave generating unit are used to perform microwave sterilization treatment and microwave heating pulverization treatment on the biological waste;

[0031] Treatment of exhaust gas after ashing: A large amount of flue gas generated during the microwave heating ashing process is treated by an exhaust gas treatment unit, wherein a catalytic combustion furnace is used to catalytically oxidize a large amount of flue gas, and the flue gas after catalytic oxidation is discharged into a Y-shaped structure mixed air interface, and the catalytic flue gas is cooled by mixed air. The cooled flue gas is subjected to carbon dioxide adsorption by a carbon dioxide adsorber, and the exhaust gas after adsorption treatment is discharged through a negative pressure fan.

[0032] The system and method for treating radioactive biological waste of the present invention have the following beneficial effects compared with the prior art:

[0033] (1) It can selectively heat the water and organic matter in the biological waste directly, with small thermal inertia and high heating efficiency;

[0034] (2) It can realize microwave incineration treatment of radioactive biological waste, and has the capabilities of pre-treatment, heating incineration, and tail gas treatment of biological waste, so as to realize the conversion of radioactive biological waste into radioactive solid waste and further reduce the volume of waste.

[0035] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 It is a schematic diagram of a system for treating radioactive biological waste according to the present invention. DETAILED DESCRIPTION

[0038] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0039] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0040] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0041] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more". "Plurality" should be understood as two or more.

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0043] Figure 1 A schematic diagram of a system for treating radioactive biological waste according to the present invention is shown, comprising Figure 1 It can be seen that the treatment system for radioactive biological waste of the present invention includes a pretreatment unit 1 , an ashing and heating unit 2 and a tail gas treatment unit 3 .

[0044] The pre-processing unit 1 includes a crushing unit 4 and a conveying unit 5. According to actual needs, the crushing inlet of the crushing unit 4 in the pre-processing unit 1 is preferably set to a rectangular shape, for example, its cross-sectional size can be designed to be 400×200 mm. It can be understood that the crushing unit 4 also includes a motor, a crushing mechanism, and a shell, and the crushing inlet is set on the shell.

[0045] A rectangular material channel is provided below the crushing unit 4 for conveying the radioactive biological waste crushed by the crushing unit 4 to the conveying unit 5. In one embodiment, the rectangular material channel is designed to be 410×210 mm in size. The crushing unit 4 and the rectangular material channel are connected by screws. The conveying unit 5 can be in the form of a conveyor belt.

[0046] In a specific embodiment, the comminution unit 4 uses mechanical crushing teeth as a crushing mechanism.

[0047] The conveying unit 5 is fixedly connected to the rectangular material channel, and the material inlet of the conveying unit 5 is arranged below the rectangular material channel. After being crushed by the crushing unit 4, the biological waste enters the conveying unit 5 under the action of gravity.

[0048] Based on the requirement of waste minimization in radioactive waste management, the volume of waste should be reduced as much as possible in the treatment of radioactive biological waste, so heating incineration is used to reduce the volume of waste.

[0049] The crushed radioactive biological waste is transported to the ashing heating unit 2 by the transport unit 5. Figure 1As shown, the ashing heating unit 2 includes a microwave generating unit 6, an ashing heating cavity 7, a microwave control unit 8, a microwave cooling unit 9 and a sensitizer adding unit 10, wherein the microwave generating unit 6 is used to generate microwaves to sterilize and heat the contents in the ashing heating cavity 7; the microwave control unit 8 is used to control the power and switch of the microwave generating unit 6 and monitor the temperature, pressure and other process parameters in the ashing heating cavity 7, which ensures that the operating condition of the microwave generating unit is consistent with the microwave ashing heating process by controlling the power and switch of the microwave generating unit 6 and simultaneously monitoring the temperature, pressure and other process parameters in the ashing heating cavity 7; the microwave cooling unit 9 includes a chiller and a cooling water pipeline, wherein the chiller maintains cooling water at a specified temperature, and the cooling water pipeline is wound around the microwave generating unit 6 to reduce the temperature of the microwave generating unit 6 when it is working, to ensure that the operating temperature of the microwave generating unit 6 is in normal working conditions during operation, wherein the cooling water inlet and outlet interface is located at the outermost side of the device. The sensitizer adding unit 10 is arranged in the process route before the ashing heating chamber 7, and is used to add microwave sensitizer to the crushed radioactive biological waste to enhance the effect of microwave ashing, wherein the microwave sensitizer can be any one of ferroferric oxide sensitizer, aluminum powder, zinc powder, activated carbon, and graphite powder.

[0050] In a specific arrangement of the ashing heating unit 2, the ashing heating cavity 7 is a rectangular parallelepiped and is located in the center, and the microwave generating unit 6 is installed on the left and right sides of the ashing heating cavity 7 in a side-mounted manner. The microwave control unit 8 is controlled by an integrated PLC, and its components are located at the outermost side of the ashing heating cavity 7. The sensitizer adding unit 10 is located between the ashing heating cavity 7 and the conveying unit 5.

[0051] The crushed radioactive biological waste arrives below the sensitizer adding unit 10 under the action of the conveying unit 5, and microwave sensitizer is added through the sensitizer adding pipeline of the sensitizer adding unit 10, so that the microwave sensitizer falls on the surface of the crushed waste.

[0052] It can be understood that the speed at which the conveying unit 5 passes under the sensitizer adding unit 10 depends on the amount of biological waste added, the moving speed of the conveying unit and the type of microwave sensitizer.

[0053] The biological waste added with the microwave sensitizer is transported to the ashing heating vessel in the ashing heating chamber 7 through the transport unit 5 , and the ashing heating vessel is preferably a corundum crucible.

[0054] The waste in the ashing heating vessel is first sterilized under the action of microwaves, and then ashed under the heating action of the microwave generating unit 6. The ashing heating vessel contains treated solid waste in the form of incineration ash, which accounts for about 0.01% of the original waste mass.

[0055] During the microwave heating ashing process, a large amount of smoke (or tail gas) will be generated, and the smoke is transmitted to the tail gas treatment unit 3 through the tail gas conveying pipeline for treatment.

[0056] The tail gas treatment unit 3 includes a catalytic combustion furnace 11, an air mixing interface 12, a carbon dioxide adsorber 13 and a negative pressure fan 14, wherein the catalytic combustion furnace 11, the air mixing interface 12, the carbon dioxide adsorber 13 and the negative pressure fan 14 are connected in sequence.

[0057] It can be understood that the ashing heating chamber 7 is connected to the catalytic combustion furnace 11 through an exhaust gas conveying pipeline, so that the flue gas generated by the ashing heating chamber 7 is conveyed to the catalytic combustion furnace 11 through the exhaust gas conveying pipeline.

[0058] The catalytic combustion furnace 11 is a regenerative catalytic combustion furnace (RCO) for decomposing organic waste in the flue gas into carbon dioxide and water.

[0059] The air mixing interface 12 is a Y-shaped structure air mixing interface, which has two Y-shaped bifurcations and a straight air mixing pipeline, wherein one Y-shaped bifurcations is connected to the air mixing gas pipeline, and the other Y-shaped bifurcations is connected to the catalytic combustion exhaust gas outlet of the catalytic combustion furnace 11. The air mixing gas and the catalytic combustion exhaust gas are mixed in the straight air mixing pipeline after the air mixing interface. In a specific embodiment, the straight air mixing pipeline is designed to be 1000 mm.

[0060] The carbon dioxide adsorber 13 is a carbon dioxide adsorber using soda lime as an adsorbent, and is used to achieve adsorption of carbon dioxide in the tail gas using a carbon dioxide solid adsorption method, with an adsorption efficiency of about 99%.

[0061] The negative pressure fan 14 is connected to the carbon dioxide adsorber 13, and is used to discharge the gas (exhaust gas) adsorbed by the carbon dioxide adsorber 13 out of the system, wherein the radioactivity level of the exhaust gas meets the emission requirements after being processed by the treatment system for radioactive biological waste of the present invention.

[0062] The treatment system for radioactive biological waste of the present invention can realize microwave ashing treatment of radioactive biological waste, has the capabilities of pre-treatment, heating ashing and tail gas treatment of biological waste, realizes the conversion of radioactive biological waste into radioactive solid waste, and further reduces the volume of waste.

[0063] The method for treating radioactive biological waste using the above-mentioned system for treating radioactive biological waste comprises the following steps:

[0064] Pretreatment of radioactive biological waste: using the crushing unit 4 in the pretreatment unit 1 to crush the biological waste;

[0065] Ashing treatment of radioactive biological waste: The biological waste after pulverization treatment is transported to the ash heating unit 2 by the conveying unit 5, wherein, before being transported to the ash heating cavity 7 in the ash heating unit 2, a microwave sensitizer is added to the pulverized biological waste through the sensitizer adding pipeline of the sensitizer adding unit 10; the biological waste is subjected to microwave sterilization treatment and microwave heating ash treatment by the microwaves emitted by the microwave generating unit 6 in the ash heating cavity 7;

[0066] Treatment of exhaust gas after ashing: A large amount of flue gas generated during the microwave heating ashing process is treated by an exhaust gas treatment unit 3, wherein a large amount of flue gas is catalytically oxidized by a catalytic combustion furnace 11, and the flue gas after catalytic oxidation is discharged into a Y-shaped structure mixed air interface, and the catalytic flue gas is cooled by a mixed air method. The cooled flue gas is subjected to carbon dioxide adsorption by a carbon dioxide adsorber 13, and the exhaust gas after adsorption treatment is discharged through a negative pressure fan 14.

[0067] The above method can be used to safely and quickly treat radioactive biological waste.

[0068] Those skilled in the art can understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for treating radioactive biological waste, characterized in that: It includes a pretreatment unit, an ashing heating unit and an exhaust gas treatment unit, wherein: The pretreatment unit is configured to pulverize the radioactive biological waste, and includes a pulverization unit and a conveying unit. The radioactive biological waste treated by the pretreatment unit is conveyed to the ashing and heating unit through the conveying unit. The ashing and heating unit is configured to use microwave technology to perform microwave sterilization and microwave ashing heating on the pulverized radioactive biological waste, and the flue gas generated during the microwave ashing heating process of the ashing and heating unit is transported to the tail gas treatment unit through a pipeline; The tail gas treatment unit is configured to treat the flue gas generated by the ashing and heating unit during the ashing and heating process, and the treatment includes: catalytic oxidation, cooling, adsorption and harmless tail gas emission of the flue gas.

2. The system for treating radioactive biological waste according to claim 1, characterized in that: The crushing unit comprises a motor, a crushing mechanism and a shell. The shell is provided with a rectangular crushing inlet. The crushing mechanism is a mechanical crushing tooth.

3. The system for treating radioactive biological waste according to claim 1, characterized in that: The ashing heating unit comprises a microwave generating unit, an ashing heating cavity, a microwave control unit, a microwave cooling unit and a sensitizer adding unit, wherein: The microwave generating unit is configured to generate microwaves to sterilize and heat the radioactive biological waste in the ashing heating cavity, and is arranged around the ashing heating cavity; The microwave control unit is configured to control the power and switch of the microwave generating unit and monitor the temperature and pressure in the ashing heating cavity to ensure that the operating condition of the microwave generating unit is consistent with the microwave ashing heating process; The microwave cooling unit comprises a water chiller and a cooling water pipeline; The sensitizer adding unit is arranged before the ashing heating cavity, and is used to add microwave sensitizer to the crushed radioactive biological waste transported in the conveying unit, so as to enhance the effect of microwave ashing.

4. The system for treating radioactive biological waste according to claim 3, characterized in that: The chiller maintains cooling water at a specified temperature, and the cooling water pipeline is wound around the microwave generating unit to reduce the temperature of the microwave generating unit when it is working, ensuring that the operating temperature of the microwave generating unit is in a normal working condition during operation.

5. The system for treating radioactive biological waste according to claim 3, characterized in that: The microwave sensitizer is any one of ferroferric oxide sensitizer, aluminum powder, zinc powder, activated carbon and graphite powder.

6. The system for treating radioactive biological waste according to claim 3, characterized in that: The speed at which the conveying unit passes under the sensitizer adding unit depends on the amount of biological waste added, the moving speed of the conveying unit and the type of microwave sensitizer.

7. The system for treating radioactive biological waste according to claim 3, characterized in that: An ashing heating vessel is arranged in the ashing heating cavity, and the ashing heating vessel is a corundum crucible.

8. The system for treating radioactive biological waste according to claim 3, characterized in that: The tail gas treatment unit includes a catalytic combustion furnace, an air mixing interface, a carbon dioxide adsorber and a negative pressure fan, wherein the catalytic combustion furnace, the air mixing interface, the carbon dioxide adsorber and the negative pressure fan are connected in sequence, wherein: The ashing heating chamber is connected to the catalytic combustion furnace via an exhaust gas delivery pipeline; The catalytic combustion furnace is configured to decompose organic waste in the flue gas into carbon dioxide and water; The air mixing interface is a Y-shaped structure air mixing interface, which has two Y-shaped bifurcations and a straight air mixing pipeline, wherein one Y-shaped bifurcations is connected to the air mixing gas pipeline, and the other Y-shaped bifurcations is connected to the catalytic combustion tail gas exhaust outlet of the catalytic combustion furnace, and the air mixing process is realized in the straight air mixing pipeline behind the air mixing interface with the catalytic combustion tail gas; The carbon dioxide adsorber is configured to adsorb carbon dioxide in the tail gas using a carbon dioxide solid adsorption method; The negative pressure fan is connected to the carbon dioxide adsorber and is configured to discharge the remaining gas adsorbed by the carbon dioxide adsorber out of the system.

9. The system for treating radioactive biological waste according to claim 8, characterized in that: The catalytic combustion furnace is a regenerative catalytic combustion furnace.

10. A method for treating radioactive biological waste using the treatment system according to claim 8 or 9, comprising the following steps: Pretreatment of radioactive biological waste: Use the crushing unit in the pretreatment unit to crush the biological waste; Ashing treatment of radioactive biological waste: the biological waste after pulverization is transported to the pulverization heating unit by using a conveying unit, wherein, before being transported to the pulverization heating cavity in the pulverization heating unit, a microwave sensitizer is added to the pulverized biological waste through a sensitizer adding pipeline of a sensitizer adding unit; in the pulverization heating cavity, microwaves emitted by a microwave generating unit are used to perform microwave sterilization treatment and microwave heating pulverization treatment on the biological waste; Treatment of exhaust gas after ashing: A large amount of flue gas generated during the microwave heating ashing process is treated by an exhaust gas treatment unit, wherein a catalytic combustion furnace is used to catalytically oxidize a large amount of flue gas, and the flue gas after catalytic oxidation is discharged into a Y-shaped structure mixed air interface, and the catalytic flue gas is cooled by mixed air. The cooled flue gas is subjected to carbon dioxide adsorption by a carbon dioxide adsorber, and the exhaust gas after adsorption treatment is discharged through a negative pressure fan.

Images