Radioactive organic-nitrate slurry treatment system and method

Abstract

The invention relates to a radioactive organic-nitrate slurry treatment system and method. The treatment system comprises a steam reforming reaction device, a carbon reduction reforming reaction device and a filtering device. The treatment method comprises the following steps: S1, in the steam reforming reaction device pre-filled with a first solid, performing a first reaction on radioactive organic-nitrate slurry, a first additive and a first oxidant; s2, performing a second reaction on a reaction product of the first reaction, a second additive and a second oxidant in the carbon reduction reforming reaction device pre-filled with a second solid; and S3, in the filtering device, filtering a reaction product of the second reaction. According to the invention, safe and efficient treatment and final safe disposal of the radioactive organic nitrate slurry can be realized.

Description

Technical Field

[0001] This invention relates to a system and method for treating radioactive organic-nitrate sludge. Background Technology

[0002] Wastewater generated in all stages of nuclear industry production and operation contains nitrates. This type of wastewater is characterized by radioactive contamination, high organic matter content, and high salinity, making it extremely difficult to treat and dispose of. Currently, the main methods for removing nitrates include catalytic denitrification, electrodialysis, reverse osmosis, biological denitrification, and ion exchange. However, in practice, none of these methods have achieved satisfactory results. Treating nitrate waste that simultaneously exhibits radioactive contamination, high organic matter content, and high salinity is even more challenging. Radioactive organic nitrate sludge generated during nuclear industry production and operation is one such example.

[0003] Traditional methods for treating radioactive mud (with its complex composition) include cement hardening, vacuum microwave drying, and vitrification. However, these traditional techniques present numerous challenges for mud containing organic matter, nitrates, and high salinity. For example, the presence of nitrates increases the diffusion and migration of radionuclides, and the presence of organic components prevents the long-term stable fixation of radionuclides in the cement-hardened product. Furthermore, the inability to completely destroy organic components and nitrates makes vitrification or other processing impossible. Summary of the Invention

[0004] This invention addresses the problems in existing technologies, such as the increased diffusion and migration of radionuclides due to the presence of nitrates, and the inability of the presence of organic components to achieve long-term stable fixation of radionuclides in cement-cured products. It provides a system and method for treating radioactive organic-nitrate slurry. This invention enables the safe and efficient treatment and final safe disposal of radioactive organic-nitrate slurry.

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

[0006] In a first aspect, the present invention provides a treatment system for radioactive organic-nitrate sludge, which includes a steam reforming reactor, a carbon reduction reforming reactor, and a filtration device.

[0007] The steam reforming reactor is provided with a first slag discharge port, a first additive inlet, a first feed inlet, a first oxidant inlet, and a first discharge port; the first discharge port is positioned higher than the first additive inlet, the first feed inlet, and the first oxidant inlet.

[0008] The carbon reduction reforming reactor is provided with a second slag discharge port, a second additive inlet, a second feed inlet, a second oxidant inlet, and a second discharge port; the second discharge port is positioned higher than the second additive inlet, the second feed inlet, and the second oxidant inlet; the first discharge port is connected to the second feed inlet;

[0009] The filter device has a third inlet and a third outlet; the second outlet is connected to the third inlet.

[0010] In this invention, the steam reforming reactor can be a fluidized bed reactor.

[0011] In this invention, the steam reforming reactor may include an integrally formed first fixed section and a first enlarged section, with the first enlarged section located above the first fixed section. The first fixed section is a solid bed containing a first solid. The first fixed section may be shaped like an inverted frustum. The first slag discharge port may be located on the first fixed section. The first enlarged section is partially filled with the first solid. The first enlarged section may be cylindrical. The first additive inlet, the first feed inlet, the first oxidant inlet, and the first discharge port may be located on the first enlarged section.

[0012] In this invention, conventionally, the position of the first slag discharge port can be lower than the first additive inlet, the first feed inlet, and the first oxidant inlet.

[0013] In this invention, a cyclone separator is provided at the top of the steam reforming reactor. The cyclone separator includes a hopper and a return pipe. The outlet of the hopper is the first discharge port, and the return pipe is inserted into the steam reforming reactor.

[0014] In this invention, a mud storage tank can be connected to the first feed inlet. A feed pump can be provided between the mud storage tank and the first feed inlet. A temporary storage tank can also be provided between the mud storage tank and the feed pump. The feed pump can be a peristaltic pump.

[0015] In this invention, the first additive feed tank can be connected to the first additive inlet.

[0016] In this invention, the oxygen supply system and the steam boiler can be connected to the first oxidant inlet.

[0017] In this invention, an oxygen monitor and a hydrogen monitor can be installed at the first discharge port.

[0018] In this invention, the carbon reduction reforming reactor can be a fluidized bed reactor.

[0019] In this invention, the carbon reduction reforming reactor may include an integrally formed second fixed section and a second enlarged section, with the second enlarged section located above the second fixed section. The second fixed section is a solid bed containing a second solid. The second fixed section may be shaped like an inverted frustum. A second slag discharge port may be disposed on the second fixed section. The second enlarged section is partially filled with the second solid. The second enlarged section may be cylindrical. A second additive inlet, a second feed inlet, a second oxidant inlet, and a second discharge port may be disposed on the second enlarged section.

[0020] In this invention, conventionally, the position of the second slag discharge port can be lower than that of the second additive inlet, the second feed inlet, and the second oxidant inlet.

[0021] In this invention, the second additive feed tank can be connected to the second additive inlet.

[0022] In this invention, the oxygen supply system can be connected to the second oxidant inlet.

[0023] In this invention, an oxygen monitor can be installed at the second discharge port.

[0024] In this invention, the filtration device may include a pulse bag filter, an activated carbon adsorber, and a high-efficiency filter connected in sequence. A third slag discharge port and a third feed port are located on the pulse bag filter, and the third discharge port is the discharge port of the high-efficiency filter. The pulse bag filter may be a vertical container. A vacuum ejector may be installed on the connecting pipe between the pulse bag filter and the activated carbon adsorber. A gas monitor may be installed at the outlet of the vacuum ejector. A heater may be installed externally on the pulse bag filter. A gas monitor may be installed at the outlet of the pulse bag filter.

[0025] In this invention, the filtration device may also have a third slag discharge port. The position of the third slag discharge port may be lower than the third feed port. The first slag discharge port and the second slag discharge port may be connected to the feed port of the solid waste collection tank. The third slag discharge port may be connected to the feed port of the solid waste collection tank.

[0026] In this invention, the third discharge port can be connected to an exhaust fan. The exhaust fan's outlet can be equipped with a continuous emission monitoring device.

[0027] In this invention, a cooler may be provided on the pipeline connecting the second discharge port and the third inlet port.

[0028] Secondly, the present invention provides a method for treating radioactive organic-nitrate mud, which employs the radioactive organic-nitrate mud treatment system described above, and includes the following steps:

[0029] S1. In the steam reforming reactor pre-filled with the first solid, a first reaction is carried out with radioactive organic-nitrate slurry, a first additive, and a first oxidant; the first additive includes a mineralizing additive, a metal catalyst, and a reducing agent; the first oxidant includes steam and oxygen.

[0030] S2. In the carbon reduction reforming reactor pre-filled with the second solid, the reaction product of the first reaction, the second additive, and the second oxidant are subjected to a second reaction; the second additive includes calcium carbonate; the second oxidant includes oxygen.

[0031] S3. The reaction product of the second reaction is filtered in the filtration device.

[0032] In this invention, in step S1, the first solid may be a mineralizing additive, such as clay.

[0033] In this invention, in step S1, the radioactive organic-nitrate sludge may include radioactive heavy metal salts, organic matter, and nitrates. The radioactive heavy metal salts include uranium salts. The organic matter may include waste oil or waste organic solvents. The nitrates may include sodium nitrate. The radioactive organic-nitrate sludge may also include at least one of nitrites, chlorides, calcium salts, and magnesium salts.

[0034] In this invention, in step S1, the feed flow rate of the radioactive organic-nitrate slurry can be 10-100 kg / h.

[0035] In this invention, in step S1, the mineralizing additive may be clay.

[0036] In this invention, in step S1, the feed flow rate of the mineralizing additive can be 5-20 kg / h.

[0037] In this invention, in step S1, the metal catalyst may be iron oxide.

[0038] In this invention, in step S1, the feed flow rate of the metal catalyst can be 5-30 kg / h.

[0039] In this invention, the reducing agent in step S1 can be carbon.

[0040] In this invention, in step S1, the feed flow rate of the reducing agent can be 10-50 kg / h.

[0041] In this invention, in step S1, the steam feed flow rate can be 20-200 kg / h, for example 100 kg / h.

[0042] In this invention, in step S1, the pressure of the steam may not exceed 15 psig.

[0043] In this invention, in step S1, the temperature of the steam can be 600°C.

[0044] In this invention, in step S1, the oxygen feed flow rate can be 10-200 Nm³. 3 / h, for example, 50Nm 3 / h.

[0045] In this invention, in step S1, the pressure of the first reaction can be -9.9 to 0 kPa, preferably -4.98 to 0 kPa, for example -2 kPa.

[0046] In this invention, in step S1, the temperature of the first reaction can be 600-800℃, for example 750℃.

[0047] In this invention, in step S1, the residence time of the first reaction can be 2 seconds.

[0048] In this invention, in step S2, the second solid may be calcium carbonate.

[0049] In this invention, in step S2, the feed flow rate of the reaction product of the first reaction can be 200-2000 Nm. 3 / h, for example 550Nm 3 / h.

[0050] In this invention, in step S2, the feed flow rate of calcium carbonate can be 5-20 kg / h, for example 10 kg / h.

[0051] In this invention, in step S2, the oxygen feed flow rate can be 10-200 Nm³. 3 / h, for example, 60Nm 3 / h.

[0052] In this invention, in step S2, the pressure of the second reaction can be -9.9 to 0 kPa, for example -5 kPa.

[0053] In this invention, in step S2, the temperature of the second reaction can be 800-1100℃, for example 1000℃.

[0054] In this invention, in step S2, the residence time of the second reaction can be 2 seconds.

[0055] In this invention, in step S3, before filtration, the reaction product of the second reaction can be cooled to 180-250°C.

[0056] Unless otherwise specified, the term "pressure" in this invention refers to gauge pressure.

[0057] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0058] The reagents and raw materials used in this invention are all commercially available.

[0059] The positive and progressive effects of this invention are as follows:

[0060] (1) The processing system of the present invention introduces waste materials, superheated steam and related additives into a steam reforming reactor. The liquid is heated and evaporated, the organic matter is reformed and decomposed, and the active chemical substances in the waste feed are completely converted into stable mineralized products, which contain almost all radionuclides and heavy metals.

[0061] (2) The treatment system of the present invention adopts a fluidized bed design. The steam reforming reactor provides a large surface area to allow the waste to react fully and effectively; it effectively treats and fixes radioactive waste liquid and sludge containing high concentrations of sodium, aluminum, nitrate, nitrite, nitric acid, hydroxide and sulfate, as well as a large amount of radioactive nuclides, chlorides, fluorides, phosphates, heavy metals and other inorganic elements.

[0062] (3) In the processing method of the present invention, the reducing additive can directly reduce nitric acid, nitrate and nitrite in the reforming reaction device to nitrogen gas; adding clay or other inorganic co-reactants to the waste feed or fluidized bed can convert radionuclides, alkali metals, sulfates, chlorides, fluorides, phosphates and non-volatile heavy metals into fixed mineral products. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the treatment system for radioactive organic-nitrate sludge in Example 1;

[0064] The following components are labeled in the diagram: 1. First additive feed tank; 2. Feed pump; 3. Steam reforming reaction device; 3. First solid; 30. First fixed section; 31. First expansion section; 32. Air duct; 301. Return pipe; 302. Second additive feed tank; 4. Carbon reduction reforming reaction device; 5. Second solid; 50. Second fixed section; 51. Second expansion section; 52. Cooler; 53. Pulse bag filter; 6. Vacuum ejector; 61. Activated carbon adsorber; 7. High-efficiency filter; 8. Exhaust fan; 9. Solid waste collection tank; 10. Detailed Implementation

[0065] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0066] In this embodiment, the basic information of the main components and materials is summarized as follows:

[0067] Slurry Storage Tanks: Radioactive organic nitrate slurry is metered directly from slurry storage tanks (storage tanks, waste tankers, or shipping containers) into the steam reforming reactor 3. During slurry transfer, the mass and density of the incoming slurry can be measured online. Based on the online measurement readings, the required co-reactants and reducing agents are then calculated using a control system algorithm. Frequent sample collection and analysis before slurry processing is unnecessary. In the processing, the addition rate of co-reactants can be varied to optimize additive use, eliminating the need for premixing additives with the slurry. Sampling can be performed for each major slurry type to determine the optimal types of co-reactants and additives, and the range for additive calculations can be pre-defined.

[0068] Radioactive organic nitrate mud: Waste generated during the uranium refining process in nuclear chemical industry. Its main chemical components are sodium nitrate, other nitrates and nitrites. The minor chemical components are inorganic substances, sulfates, chlorides and calcium-containing compounds. The main organic waste is waste oil and waste organic solvents. The minor waste also contains heavy metals (uranium and magnesium, etc.).

[0069] Steam reforming reactor 3: Made of high-temperature alloy, designed and manufactured in accordance with Section 8, Part 2 of the ASME Pressure Vessel Code, enabling it to withstand pressure surges under disturbance or abnormal conditions.

[0070] Carbon reduction reforming reactor unit 5: Consists of an alloy shell and an internal refractory lining. The reactor unit is designed and manufactured in accordance with Section 8, Part 2 of the ASME Pressure Vessel Code, enabling it to withstand pressure surges from disturbances or abnormal conditions.

[0071] Solid waste treatment system: for further treatment of solid waste received in solid waste collection tank 10, providing two main treatment pathways: first, non-single final waste form, where particulate solids are disposed of or stored as free-flowing solids in bulk containers; second, single final waste form, where particulate product solids are mixed with cementitious binders, and the slurry is placed in bulk containers, the solids and binder mixture forming a monolithic solid with a compressive strength exceeding 500 psi.

[0072] Water supply system: Used to supply cooling water. An automatic electromagnetic isolation valve can be installed on the water supply pipeline to quickly cut off the water supply when the automatic process stops or starts.

[0073] Data monitoring and acquisition system: Provides a computerized human-machine interface for all aspects of the process. The system offers fully remote operation of all systems in radioactive and contaminated areas, as well as auxiliary and utility services interfaced with heat treatment. It provides multi-level alarm functions, interlocking, and automatic control capabilities. The system is located in a dedicated control room where operators continuously monitor process and facility operation. The control room is equipped with remote closed-circuit television monitors, CEMS, and radioactivity monitoring readings.

[0074] Motor Control Center: Equipped with protective switchgear, an outdoor transformer for the motor control center and an uninterruptible power supply (UPS), it safely distributes power and controls all electrical equipment. The UPS is designed to provide 20 minutes of continuous data monitoring and acquisition for all instruments, controls, and valves in the event of a complete power outage. An optional backup generator is available if no safe secondary power source is available to maintain the ventilation system in the event of a complete power loss. All thermal and process operations can be safely resumed in less than one minute in the event of a complete power loss. The motor control center bus is separate and the electrical loads are arranged to ensure redundant blower shutdowns on different buses.

[0075] Steam boiler: Used to produce steam, with demineralized water supply system providing water to the steam boiler.

[0076] Instrument air supply system: If instrument air is not available at the system installation location, two redundant air compressors and dryers provide instrument air. The instrument air supply system powers remotely driven valves and operates power tools during maintenance. The system also provides air to maintenance personnel for breathing and cooling when contact maintenance is required in potentially contaminated areas. The breathing air system provides adsorbers, filters, and controls to ensure personnel safety. Compressed service air is required to power process jets. The HVAC system provides temperature control and plant ventilation in accessible areas of the process facility.

[0077] Nitrogen Supply System: Located outdoors. Nitrogen is used as a purging gas for instruments during operation of the radioactive organic nitrate sludge treatment system to prevent moisture buildup in process pressure transmitter sensor lines and to clean and / or cool waste feed injectors and waste packaging system seals. Nitrogen is also used to transfer dry solids to prevent excessive agglomeration caused by excessive moisture. The nitrogen supply system provides normal nitrogen requirements via a liquid nitrogen supply tank and evaporator. The system also provides a continuous supply of purging nitrogen in the event of a power outage. Nitrogen is used to clean all equipment during shutdown operations, ideally within one minute, even in the event of a complete power outage.

[0078] Oxygen supply system: Provides gaseous oxygen feed to the outdoor liquid oxygen tank and evaporator. It is supplied to the steam reforming reactor 3 and the carbon reduction reforming reactor 5 via gas distributors. The oxygen supply system consists of qualified and specially cleaned stainless steel components and automatic isolation valves.

[0079] Example 1

[0080] A treatment system for radioactive organic-nitrate sludge, such as Figure 1 It includes a steam reforming reactor 3, a carbon reduction reforming reactor 5, and a filtration device;

[0081] The steam reforming reactor 3 has a first slag discharge port, a first additive inlet, a first feed inlet, a first oxidant inlet, and a first discharge port; the first slag discharge port is located lower than the first additive inlet, the first feed inlet, and the first oxidant inlet; the first discharge port is located higher than the first additive inlet, the first feed inlet, and the first oxidant inlet.

[0082] The carbon reduction reforming reactor 5 has a second slag discharge port, a second additive inlet, a second feed inlet, a second oxidant inlet, and a second discharge port; the second slag discharge port is located lower than the second additive inlet, the second feed inlet, and the second oxidant inlet; the second discharge port is located higher than the second additive inlet, the second feed inlet, and the second oxidant inlet; the first discharge port is connected to the second feed inlet;

[0083] The filter device has a third slag discharge port, a third feed port and a third discharge port; the third slag discharge port is located lower than the third feed port; the second discharge port is connected to the third feed port.

[0084] In this embodiment, the steam reforming reactor 3 is a fluidized bed reactor, divided into two parts. The lower part is the first fixed section 31, which is a solid bed containing the first solid 30, and is generally shaped like an inverted frustum. The upper part is the first enlarged section 32, which is generally cylindrical and partially filled with the first solid 30, forming a larger diameter separation space. The first enlarged section 32 reduces the gas velocity and causes solid particles to detach from the rising gas. Most of the particles drawn into the fluidized gas fall back onto the bed by gravity. The first slag discharge port is located on the first fixed section 31. The first additive inlet, the first feed inlet, the first oxidant inlet, and the first discharge port are located on the first enlarged section 32.

[0085] In this embodiment, a cyclone separator is installed at the top of the steam reforming reactor 3. The cyclone separator includes a hopper 301 and a return pipe 302. The outlet of the hopper 301 is the first discharge port, and the return pipe 302 can be inserted into the first solid 30. The cyclone separator can effectively remove most of the fine particles entrained in the fluidized gas. The return pipe 302 allows the solid particles to fall back into the steam reforming reactor 3. The process gas of the steam reforming reactor 3 mainly consists of water vapor, carbon dioxide, hydrogen, carbon monoxide, and nitrogen, and also contains trace amounts of volatile organic compounds and acidic gases, as well as some solid products and carbon particle carriers.

[0086] In this embodiment, the mud storage tank is connected to the first feed inlet, and a feed pump 2 is provided between the mud storage tank and the first feed inlet. In this embodiment, a temporary storage tank is also provided between the mud storage tank and the feed pump 2 to provide greater storage capacity, minimizing the frequency of waste transfer from the facility. In this embodiment, the feed pump 2 is a peristaltic pump because it requires minimal maintenance, involving only hose replacement. In other embodiments, screw pumps can also be used for larger systems.

[0087] In this embodiment, the first additive feed tank 1 is connected to the first additive inlet. The first additive feed tank 1 includes mineralizing additives, metal catalysts, and reducing agents. In this embodiment, the mineralizing additives and reducing agents are supplied through two loss-in-weight feeders with air locks, while the metal catalyst and other additives are supplied through a hopper with a remote isolation valve. The outlets of the two feeders and the hopper are connected to the first additive feed tank, and then enter the steam reforming reactor 3 at a height close to the center of the first solid 30 via a common solid conveying pipeline. During this process, a small stream of nitrogen gas can be used to purge the pipeline to keep it unobstructed. In this embodiment, clay is used as a mineralizing additive to convert the accumulated product solids into a completely immobilized insoluble product, which is then semi-continuously removed from the first slag discharge port. Iron oxide is used as a metal catalyst, which is directly introduced through the first additive inlet during operation. Carbon is semi-continuously added into the steam reforming reactor 3 as a reducing agent to provide carbon and energy for the reforming reaction.

[0088] In this embodiment, the oxygen supply system and steam boiler are connected to the first oxidant inlet. Radioactive organic nitrate slurry is injected into the bottom of the first solid 30 by the feed pump 2, that is, above the first oxidant inlet. The water in the slurry evaporates and is superheated instantly upon contact with the high-temperature first solid 30, reaching the bed temperature. As the water in the slurry evaporates, the dried slurry solid is rapidly heated to the reaction temperature. The organic matter in the slurry is volatilized and pyrolyzed upon contact with the hot bed solid. Volatile organic compounds undergo steam reforming in the bed, and when they come into contact with the reducing agent on the bed, nitric acid, nitrates, and nitrites are converted into nitrogen gas. Alkali metals, non-volatile heavy metals, radioactive nuclides, inorganic components such as S, Cl, F, and P combine with co-reactants such as clay to form stable, high-melting-point, crystalline minerals, which become the final solid product. Superheated steam, residual acidic gases, powdered product particles, and some carbon powder are carried out of the first solid 30 by fluidization and the upward flow of reaction product gases.

[0089] In this embodiment, an oxygen monitor and a hydrogen monitor are installed at the first discharge port. To achieve process control, the steam reforming reactor 3 monitors the process gases at the first discharge port, including online display of oxygen and hydrogen. The hydrogen monitor is used to control the level of the reducing agent in the steam reforming reactor 3. The conversion of nitric acid, nitrate, and nitrite to nitrogen is proportional to the level of hydrogen produced in the steam reforming reactor 3 during the reforming reaction. If the hydrogen level exceeds the required level (15 vol%), the amount of carbon added should be reduced. If the hydrogen level is below the required level (15 vol%), the carbon addition rate should be increased. If the oxygen content at the first discharge port increases to above 2 vol%, the entire process system needs to be shut down. In this case, oxygen, steam, and waste are isolated within the steam reforming reactor 3, and the entire system is purged with nitrogen using a nitrogen supply system. During nitrogen purging, nitrogen can enter from the first additive inlet and / or the first slag discharge port and exit from the first discharge port.

[0090] In this embodiment, the carbon reduction reforming reactor 5 is a fluidized bed reactor, divided into two parts. The lower part is the second fixed section 51, which is a solid bed containing the second solid 50, and is generally shaped like an inverted frustum. The upper part is the second enlarged section 52, which is generally cylindrical and partially filled with the second solid 50, forming a larger diameter separation space. The second enlarged section 52 reduces the gas velocity and causes solid particles to detach from the rising gas. Most of the particles drawn into the fluidized gas fall back onto the bed by gravity. The second slag discharge port is located on the second fixed section 51. The second additive inlet, the second feed inlet, the second oxidant inlet, and the second discharge port are located on the second enlarged section 52.

[0091] In this embodiment, the second additive feed tank 4 is connected to the second additive inlet, and the second additive feed tank 4 contains calcium carbonate. In this embodiment, calcium carbonate is supplied through a hopper, which is equipped with a fill / close valve at the top and a solid dumping valve at the bottom. The solid dumping valve of the hopper is connected to a solid conveying pipeline into the carbon reduction reforming reaction unit 5. During this process, a small stream of air purification can be used to keep the pipeline unobstructed for feeding.

[0092] In this embodiment, the oxygen supply system is connected to the second oxidant inlet. In this embodiment, the carbon reduction reforming reactor 5 is arranged downstream of the steam reforming reactor 3, and fluidization is achieved by the gas from the first outlet and the introduced oxygen. Fine solid particles washed out from the steam reforming reactor 3 also enter the carbon reduction reforming reactor 5 along with the process gas. Carbon is converted into carbon dioxide, reducing carbon powder in the washed solids. Through reaction with the calcium bed particles composed of the second solid 50 in the carbon reduction reforming reactor 5, trace amounts of acidic gas generated in the steam reforming reactor 3 are removed, producing mineralized calcium compounds. Residual volatile organic compounds, carbon monoxide, and hydrogen are oxidized into carbon dioxide and water vapor.

[0093] In this embodiment, an oxygen monitor is installed at the second discharge port. The oxygen monitor controls the oxygen output to the carbon reduction reforming reactor 5. The excess oxygen concentration level is set during process operation and then automatically controlled during operation. Calculated by volumetric free oxygen volume, the normal excess oxygen content of the tail gas from the carbon reduction reforming reactor 5 is 2%-8%.

[0094] In this embodiment, a cooler 53 is provided on the pipeline connecting the second outlet and the third inlet to cool the hot gas from the second outlet of the carbon reforming reactor 5. The cooler 53 is provided with cooling nozzles for cooling the hot gas in the pipeline. The cooling nozzles are connected to the water supply system. The cooling water and atomized air sprayed by the cooler 53 are controlled as required to keep the temperature of the downstream filter device within the required operating range.

[0095] In this embodiment, the filtration device is installed downstream of the carbon reforming reactor 5, and includes a pulse bag filter 6, an activated carbon adsorber 7, and a high-efficiency particulate air (HEPA) filter 8 connected in sequence. A third discharge port and a third feed port are located on the pulse bag filter 6, and a third discharge port is the discharge port of the HEPA filter 8. The third discharge port is connected to a fan 9. In this embodiment, the pulse bag filter 6 is a vertical container designed to remove and collect fine solid particles eluted from the carbon reforming reactor 5. In this embodiment, the pulse bag filter 6 is externally equipped with an electric heater to maintain the temperature of the filter elements and container above the gas dew point, preventing condensation of moisture on the filter medium during start-up and shutdown.

[0096] In this embodiment, a vacuum ejector 61 is provided between the pulse bag filter 6 and the activated carbon adsorber 7. The exhaust gas filtered by the pulse bag filter 6 passes through the vacuum ejector 61. The exhaust fan 9 provides negative pressure to the vacuum ejector 61 to maintain the separation space of the pulse bag filter 6, the carbon reforming reactor 5, and the steam reforming reactor 3 under negative pressure. In this embodiment, gas monitors are installed at the outlets of the pulse bag filter 6 and the vacuum ejector 61 to monitor the flow rates of total exhaust gases such as H2O, O2, N2, CO, CO2, total hydrocarbons (THC), HCl, and NOx.

[0097] In this embodiment, the high-efficiency filter 8 is equipped with multiple backups to allow for component replacement and maintain the process system in an online operating state. In this embodiment, the exhaust fan 9 provides airflow throughout the facility and controls the negative pressure level in various equipment areas. The ventilation airflow mixes with clean, cooled process waste gas before being discharged through a permitted and authorized emission chimney. In this embodiment, the exhaust fan 9's outlet is equipped with a continuous emission monitoring system (CEMS) to monitor process tail gas emissions and record data such as total hydrocarbons (THC), H2O, O2, N2, CO, CO2, HCl, SOx, and NOx for analysis and data storage.

[0098] In this embodiment, the first slag discharge port, the second slag discharge port and the third slag discharge port are connected to the feed port of the solid waste collection tank 10. The discharged waste is collected in the solid waste collection tank 10 and will be further processed by the solid waste treatment system.

[0099] Example 2

[0100] A method for treating radioactive organic nitrate mud, employing the radioactive organic nitrate mud treatment system described in Example 1, includes the following steps:

[0101] S1. In a steam reforming reactor 3 pre-filled with clay, radioactive organic-nitrate slurry, a first additive consisting of clay, iron oxide, and carbon, and a first oxidant consisting of steam and oxygen react to generate syngas; the reaction pressure is -2 kPa, the temperature is 750℃, the residence time is 2 s, the feed flow rate of the radioactive organic-nitrate slurry is 80 L / h (approximately 87 kg / h), the flow rate of clay is 5 kg / h, the flow rate of iron oxide is 5 kg / h, the flow rate of carbon is 10 kg / h, the flow rate of steam is 100 kg / h, and the flow rate of oxygen is 50 Nm³. 3 / h;

[0102] S2. In a carbon reduction reforming reactor 5 pre-filled with calcium carbonate, the reaction product of step S1, the second additive calcium carbonate, and the second oxidant oxygen are reacted; the reaction pressure is -5 kPa, the temperature is 1000℃, the residence time is 2 s, and the syngas feed flow rate is 550 Nm³.3 The feed flow rate for calcium carbonate is 10 kg / h, and the feed flow rate for oxygen is 60 Nm³ / h. 3 / h;

[0103] S3. The tail gas after the reaction is cooled to 180-250℃ by cooler 53, and then passes through pulse bag filter 6, activated carbon adsorber 7 and high efficiency filter 8 in sequence before being discharged; the solid waste generated in steam reforming reaction device 3, carbon reduction reforming reaction device 5 and pulse bag filter 6 is collected in solid waste collection tank 10.

[0104] In this embodiment, the radioactive organic-nitrate mud contains inorganic matter (including approximately 70 wt% nitrate, approximately 25 wt% nitrite, 2.5 wt% nitric acid, 2 wt% hydroxide, and 0.5 wt% sulfate, with a uranium content of 10 mg / L) and a COD of 2 million mg / L. The volume content of solid particles in the radioactive organic-nitrate mud is less than 10%.

[0105] In this embodiment, the exhaust gas contains 5 wt% oxygen, 36 wt% water, 10 wt% carbon dioxide, 49 wt% nitrogen, and ≤50 mg / Nm³ sulfur dioxide. 3 Nitrogen oxides ≤100mg / Nm 3 Solid particulate matter ≤10mg / Nm 3 .

[0106] In this embodiment, the discharged solid residue contains 96 wt% sodium-alumina-silicate (a water-insoluble compound composed of Na, K, Al, S, Cl, F, P, heavy metals, and radioactive nuclides), 1 wt% sulfate, and 3 wt% carbonate.

Claims

1. A treatment system for radioactive organic-nitrate sludge, characterized in that, It includes a steam reforming reactor (3), a carbon reduction reforming reactor (5), and a filtration device; The steam reforming reactor (3) is provided with a first slag discharge port, a first additive inlet, a first feed inlet, a first oxidant inlet, and a first discharge port; the first discharge port is located higher than the first additive inlet, the first feed inlet, and the first oxidant inlet; The carbon reduction reforming reactor (5) is provided with a second slag discharge port, a second additive inlet, a second feed inlet, a second oxidant inlet, and a second discharge port; the second discharge port is located higher than the second additive inlet, the second feed inlet, and the second oxidant inlet; the first discharge port is connected to the second feed inlet; The filter device has a third inlet and a third outlet; the second outlet is connected to the third inlet.

2. The treatment system for radioactive organic-nitrate sludge according to claim 1, characterized in that, The first slag discharge port is located lower than the first additive inlet, the first feed inlet, and the first oxidant inlet; The first additive feed tank (1) is connected to the first additive inlet; The oxygen supply system and the steam boiler are connected to the first oxidant inlet; The first discharge port is equipped with an oxygen monitor and a hydrogen monitor.

3. The treatment system for radioactive organic-nitrate sludge according to claim 1, characterized in that, The top of the steam reforming reactor (3) is provided with a cyclone separator, which includes a hopper (301) and a return pipe (302). The outlet of the hopper (301) is the first discharge port, and the return pipe (302) is inserted into the steam reforming reactor (3). The mud storage tank is connected to the first feed inlet; a feed pump (2) is provided between the mud storage tank and the first feed inlet; a temporary storage tank is also provided between the mud storage tank and the feed pump (2); the feed pump (2) is a peristaltic pump; The steam reforming reactor (3) is a fluidized bed reactor.

4. The treatment system for radioactive organic-nitrate sludge according to claim 1, characterized in that, The steam reforming reactor (3) includes an integrally formed first fixed section (31) and a first enlarged section (32), the first enlarged section (32) being located above the first fixed section (31); the first fixed section (31) is generally shaped like an inverted frustum; the first slag discharge port is disposed on the first fixed section (31); the first enlarged section (32) is generally cylindrical; the first additive inlet, the first feed inlet, the first oxidant inlet and the first discharge outlet can be disposed on the first enlarged section (32).

5. The treatment system for radioactive organic-nitrate sludge according to claim 1, characterized in that, The position of the second slag discharge port may be lower than that of the second additive inlet, the second feed inlet, and the second oxidant inlet; The second additive feed tank can be connected to the second additive inlet; The oxygen supply system can be connected to the second oxidant inlet; An oxygen monitor can be installed at the second discharge port.

6. The treatment system for radioactive organic-nitrate sludge according to claim 1, characterized in that, The carbon reduction reforming reactor (5) is a fluidized bed reactor; The carbon reduction reforming reactor (5) includes an integrally formed second fixed section (51) and a second enlarged section (52), with the second enlarged section (52) located above the second fixed section (51); The second fixed segment (51) is shaped like an inverted frustum. The second slag discharge port is located on the second fixed section (51); The second enlarged section (52) is cylindrical in shape. The second additive inlet, the second feed inlet, the second oxidant inlet and the second discharge outlet are disposed on the second enlarged section (52).

7. The treatment system for radioactive organic-nitrate sludge according to claim 1, characterized in that, The filter device is also provided with a third slag discharge port; the position of the third slag discharge port is lower than the third feed port; the first slag discharge port and the second slag discharge port are connected to the feed port of the solid waste collection tank (10); the third slag discharge port is connected to the feed port of the solid waste collection tank (10); The filtration device includes a pulse bag filter (6), an activated carbon adsorber (7), and a high-efficiency filter (8) connected in sequence. The third slag discharge port and the third feed port are located on the pulse bag filter (6), and the third discharge port is the discharge port of the high-efficiency filter (8). The pulse bag filter (6) is a vertical container; A vacuum ejector (61) is provided on the connecting pipe between the pulse bag filter (6) and the activated carbon adsorber (7); a gas monitor is installed at the outlet of the vacuum ejector (61); The pulse bag filter (6) is equipped with a heater on its exterior; A gas monitor is installed at the outlet of the pulse bag filter (6); The third discharge port is connected to the exhaust fan (9); the exhaust fan (9) is equipped with a continuous emission monitoring instrument at its outlet; A cooler (53) is installed on the pipeline connecting the second discharge port and the third inlet port.

8. A method for treating radioactive organic-nitrate mud, characterized in that, The treatment system employing the radioactive organic-nitrate sludge treatment method described in any one of claims 1-7 includes the following steps: S1. In the steam reforming reactor (3) pre-filled with the first solid (30), radioactive organic-nitrate slurry, a first additive and a first oxidant are subjected to a first reaction; the first additive includes a mineralizing additive, a metal catalyst and a reducing agent; the first oxidant includes steam and oxygen. S2. In the carbon reduction reforming reaction apparatus (5) pre-filled with the second solid (50), the reaction product of the first reaction, the second additive, and the second oxidant are subjected to a second reaction; the second additive includes calcium carbonate; the second oxidant includes oxygen. S3. The reaction product of the second reaction is filtered in the filtration device.

9. The method for treating radioactive organic-nitrate sludge according to claim 8, characterized in that, In step S1, the first solid (30) is a mineralizing additive, such as clay; And / or, in step S1, the radioactive organic-nitrate slurry comprises radioactive heavy metal salts, organic matter, and nitrates; the radioactive heavy metal salts preferably comprise uranium salts; the organic matter preferably comprises waste oil or waste organic solvents; the nitrates preferably comprise sodium nitrates; the radioactive organic-nitrate slurry further preferably comprises at least one of nitrites, chlorides, calcium salts, and magnesium salts; And / or, in step S1, the feed flow rate of the radioactive organic-nitrate slurry is 10-100 kg / h; And / or, in step S1, the mineralizing additive is clay; And / or, in step S1, the feed flow rate of the mineralizing additive is 5-20 kg / h; And / or, in step S1, the metal catalyst is iron oxide; And / or, in step S1, the feed flow rate of the metal catalyst is 5-30 kg / h; And / or, in step S1, the reducing agent is carbon; And / or, in step S1, the feed flow rate of the reducing agent is 10-50 kg / h; And / or, in step S1, the steam feed flow rate is 20-200 kg / h, for example 100 kg / h; And / or, in step S1, the pressure of the steam is not greater than 15 psig; And / or, in step S1, the temperature of the steam is 600°C; And / or, in step S1, the feed flow rate of the oxygen is 10-200 Nm 3 / h, for example 50 Nm 3 / h; And / or, in step S1, the pressure of the first reaction is -9.9 to 0 kPa, preferably -4.98 to 0 kPa, for example -2 kPa; And / or, in step S1, the temperature of the first reaction is 600-800°C, for example 750°C; And / or, in step S1, the residence time of the first reaction is 2 seconds.

10. The method for treating radioactive organic-nitrate sludge according to claim 8, characterized in that, In step S2, the second solid (50) is calcium carbonate; And / or, in step S2, the feed flow rate of the reaction product of the first reaction is 200-2000 Nm 3 / h, for example 550 Nm 3 / h; And / or, in step S2, the feed flow rate of the calcium carbonate is 5-20 kg / h, for example 10 kg / h; And / or, in step S2, the feed flow rate of the oxygen is 10-200 Nm 3 / h, for example 60 Nm 3 / h; And / or, in step S2, the pressure of the second reaction is -9.9 to 0 kPa, for example -5 kPa; And / or, in step S2, the temperature of the second reaction is 800-1100°C, for example 1000°C; And / or, in step S2, the residence time of the second reaction is 2 seconds; And / or, in step S3, before filtration, the reaction product of the second reaction is cooled to 180-250°C.

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