CN110186052A - Cool waste gasification and melting processing system and its method in movable small - Google Patents

Abstract

The invention discloses a mobile small-scale low-to-medium radioactive waste gasification melting treatment system and its method, comprising a crusher, a pneumatic diaphragm pump, a plasma gasification melting furnace, a molten glass body receiver, a combustion chamber, and a first-stage direct heat exchange filter, ceramic filter, secondary direct heat exchanger, activated carbon adsorption tower, deacidification scrubber, high efficiency air filter, chimney and mobile equipment. After pre-treatment, the waste is transported to the plasma gasification melting furnace. After the gasification reaction in the gasification zone of the furnace, the synthetic gas is generated and enters the combustion chamber for full combustion and decomposition, and then sent to the flue gas purification treatment system. The ash enters the melting zone for further processing. The vitrification melting process fixes the radionuclides in the molten glass body, and after the glass body is cooled, it is stored in drums by the automatic receiving system and then sent to the low- and medium-level radioactive waste landfill for near-surface burial. The invention has good volume reduction effect, high safety and reliability, good nuclide stability and high system process integration.

Description

Mobile small-scale medium and low radioactive waste gasification melting treatment system and method thereof

technical field

The invention relates to a gasification and melting treatment system and a method thereof, in particular to a mobile small-scale gasification and melting treatment system for medium and low radioactive waste and a method thereof.

Background technique

Nuclear facilities produce several tons of low- and medium-level radioactive waste every year. Solid waste is treated by super compression + cement solidification, and liquid waste is treated by evaporation + cement solidification technology, and finally stored in 200L steel drums. Although the cement solidification technology can achieve harmless treatment of radioactive waste, and although the super compressor can further compress and reduce the waste, cement solidification is a capacity-enhancing technology, and the space of offshore nuclear facilities is limited. However, it cannot fundamentally solve the problem of nuclide leaching and diffusion in waste. Although the incineration method for treating low-level and medium-level radioactive waste has a relatively significant volume reduction effect on combustible waste, the problem of dioxin pollution generated during the incineration process has always been the focus of attention. And because the incineration produces a large amount of flue gas, it not only increases the burden and cost of tail gas treatment, but also easily causes the further diffusion of radionuclides with the flue gas, which is not conducive to the capture and control of radionuclides. The slag cannot be melted, and cannot capture and solidify radionuclides and other heavy metals that seriously pollute the environment.

Contents of the invention

The technical problem to be solved by the present invention is to provide a mobile small-scale gasification and melting treatment system and method for medium and low radioactive waste, which have a high degree of volume reduction.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A mobile small-scale low-to-medium radioactive waste gasification and melting treatment system, characterized in that it includes a crusher, a pneumatic diaphragm pump, a plasma gasification and melting furnace, a molten glass body receiver, a combustion chamber, a first-stage direct heat exchanger, a ceramic Filters, secondary direct heat exchangers, activated carbon adsorption towers, deacidification scrubbers, high-efficiency air filters, chimneys and mobile equipment, crusher outlets are fed through shaftless screw feeders and plasma gasification melting furnaces port connection, the output end of the pneumatic diaphragm pump is connected to the feed port of the plasma gasification melting furnace through a pipeline, and the molten glass body receiver is arranged at the lower end of the plasma gasification melting furnace. The gas outlet is connected to the inlet of the combustion chamber through pipes, the outlet of the combustion chamber is connected to the inlet of the first-stage direct heat exchanger through pipes, the outlet of the first-stage direct heat exchanger is connected to the inlet of the ceramic filter through pipes, and the outlet of the ceramic filter is connected through the second-stage direct heat exchanger. The inlet of the heat exchanger is connected, the outlet of the secondary direct heat exchanger is connected to the inlet of the activated carbon adsorption tower through a pipeline, the outlet of the activated carbon adsorption tower is connected to the inlet of the deacidification scrubber through a pipeline, and the outlet of the deacidification scrubber is connected to the inlet of a high-efficiency air filter through a pipeline. High-efficiency air filter outlet is connected with the chimney, crusher, pneumatic diaphragm pump, plasma gasification melting furnace, molten glass body receiver, combustion chamber, primary direct heat exchanger, ceramic filter, secondary direct heat exchanger, activated carbon Adsorption towers, deacidification scrubbers, high-efficiency air filters and chimneys are set on mobile equipment.

Further, the plasma gasification melting furnace includes a furnace cover and a furnace body, the furnace cover is buckled on the upper end of the furnace body, and the furnace cover is provided with a solid waste feeding port and a liquid waste feeding port communicating with the furnace, and the furnace body The inner wall is provided with a heat insulation layer, the side wall of one side of the furnace body is provided with an air inlet hole, the side wall of the other side of the furnace body is provided with a synthesis gas outlet, and the furnace body is provided with a fire grate, which is set horizontally and fixed on the The inner wall of the furnace body divides the furnace into a gasification zone on the upper side of the grate and a melting zone on the lower side of the grate. There is a melting pool crucible at the lower end of the melting zone, and two thermal plasma torches are arranged in the melting pool crucible. The lower end is provided with a discharge through hole penetrating with the outer side of the furnace body.

Further, an observation and measurement window is also provided on the furnace cover.

Further, the solid waste feed port is provided with a feed bin and a control valve, the feed bin is a circular funnel and the lower end of the feed bin is fixedly connected to the upper end of the solid waste feed port, and the control valve is set at the lower end of the feed bin for To control the feeding amount.

Further, one end of the thermal plasma torch is arranged in the melting pool crucible from the outside of the furnace body through the side wall of the furnace body, and two thermal plasma torches are arranged symmetrically on both sides of the furnace body.

Further, an induction coil is arranged around the discharge through hole, and the thermal valve penetrates through the lower end of the furnace body and is arranged around the discharge through hole and the outside of the induction coil.

A mobile small-scale low-to-medium radioactive waste gasification melting treatment method is characterized in that it comprises the following steps:

Step 1: The low and medium radioactive labor protection products are crushed by the crusher and sent to the plasma gasification melting furnace by the shaftless screw feeder, and the low and medium radioactive liquid waste is sent into the plasma gasification melting furnace through the pneumatic diaphragm pump;

Step 2: Low and medium radioactive labor protection products and low and medium radioactive liquid waste enter the gasification zone of the plasma gasification melting furnace, and gasification reaction occurs at 1000-1200 ° C to form synthesis gas and ash;

Step 3: The generated synthetic gas is sent to the combustion chamber by the induced draft fan for combustion treatment, forming harmless small molecular gas;

Step 4: Ash and slag fall into the melting zone of the plasma gasification melting furnace for melting, capture and solidify radionuclides under the condition of 1200-1400°C, and finally generate harmless molten glass body, which will be cooled in 200L concrete steel barrel sealed storage;

Step 5: The high-temperature flue gas generated in step 3 is sent to the subsequent flue gas purification treatment system for treatment, and discharged after reaching the standard.

Further, the fifth step is specifically that the temperature of the high-temperature flue gas coming out of the combustion chamber is reduced to 700°C through direct heat exchange with cold air, and then the particulate matter is deeply collected through a three-stage high-temperature ceramic filter, and the dust-removed flue gas The gas is exchanged with cold air again, and the temperature of the flue gas is rapidly cooled to 200±20°C by excess air, and then enters the activated carbon adsorption device for gas radionuclide removal, and then enters the deacidification system to treat the acidic substances in the flue gas , and then use the HEPA high-efficiency air filter to intercept the fine dust in the flue gas again, and finally the flue gas is sent into the chimney through the induced draft fan and discharged into the atmosphere.

Further, the fly ash generated in the fifth step is collected and sent to the plasma gasification melting furnace for processing.

Compared with the prior art, the present invention has the following advantages and effects: the present invention utilizes the characteristics of high energy density of thermal plasma and can process high-melting-point wastes, and the low- and medium-radioactive wastes are gasified in the gasification zone. The synthesis gas is sent into the combustion chamber for combustion to form small molecular harmless substances, and the generated ash and glass body forming agent are melted in the melting zone, and the radionuclides are stably fixed in the molten glass body, and the generated flue gas is purified to meet the Emission requirements of air quality standards. Compared with the existing technology, it can achieve a volume reduction ratio of more than 95%, greatly reducing the storage space for radioactive waste treatment, and using plasma gasification melting furnace to process radioactive waste, effectively reducing processing costs and risks, and facilitating flexible control and monitoring. The invention provides an environment-friendly system and method for treating low- and medium-radioactive solid waste with good volume reduction effect, high safety and reliability, good nuclide stability, and high system process integration, which meets the requirements of the national treatment of low- and medium-radioactive solid waste. The standard of treatment to achieve the purpose of minimization and stabilization of low and medium radioactive waste.

Description of drawings

Fig. 1 is a schematic diagram of a mobile small-scale gasification and melting treatment system for low- and medium-level radioactive waste according to the present invention.

Fig. 2 is a schematic connection diagram of the mobile small-scale gasification and melting treatment system for low- and medium-level radioactive waste of the present invention.

Fig. 3 is a schematic diagram of the plasma gasification melting furnace of the present invention.

Fig. 4 is a flowchart of the gasification and melting treatment method for mobile small-scale and low-level radioactive waste according to the present invention.

Detailed ways

The present invention will be described in further detail below through examples, and the following examples are explanations of the present invention and the present invention is not limited to the following examples.

As shown in Fig. 1 or 2, a kind of mobile small-scale medium and low radioactive waste gasification and melting treatment system of the present invention includes a crusher 1, a pneumatic diaphragm pump 2, a plasma gasification and melting furnace 3, a molten glass body receiver 4, Combustion chamber 5, primary direct heat exchanger 6, ceramic filter 7, secondary direct heat exchanger 8, activated carbon adsorption tower 9, deacidification washing tower 10, high efficiency air filter 11, chimney 12 and mobile equipment 13, broken The discharge port of machine 1 is connected to the feed port of plasma gasification melting furnace 3 through a shaftless screw feeder, the output end of pneumatic diaphragm pump 2 is connected to the feed port of plasma gasification melting furnace 3 through a pipeline, and the glass body is melted The receiver 4 is set at the ash outlet at the lower end of the plasma gasification melting furnace 3, the synthesis gas outlet of the plasma gasification melting furnace 3 is connected to the inlet of the combustion chamber 5 through a pipeline, and the outlet of the combustion chamber 5 directly exchanges heat with the first stage through a pipeline The inlet of the first-stage direct heat exchanger 6 is connected to the inlet of the ceramic filter 7 through a pipe, the outlet of the ceramic filter 7 is connected to the inlet of the second-stage direct heat exchanger 8, and the outlet of the second-stage direct heat exchanger 8 is connected to the inlet of the ceramic filter 7 through a pipe. The inlet of the activated carbon adsorption tower 9 is connected, the outlet of the activated carbon adsorption tower 9 is connected to the inlet of the deacidification washing tower 10 through a pipeline, the outlet of the deacidification washing tower 10 is connected to the inlet of the high-efficiency air filter 11 through a pipeline, and the outlet of the high-efficiency air filter 11 is connected to the chimney 12 , crusher 1, pneumatic diaphragm pump 2, plasma gasification melting furnace 3, molten glass receiver 4, combustion chamber 5, primary direct heat exchanger 6, ceramic filter 7, secondary direct heat exchanger 8, activated carbon The adsorption tower 9 , the deacidification washing tower 10 , the high-efficiency air filter 11 and the chimney 12 are all arranged on the mobile device 13 .

Crusher 1 is used for crushing solid waste, which is sent to a shaftless screw feeder after being crushed to a certain size. The shaftless screw feeder operates in a sealed manner, and is designed to be explosion-proof, anti-clogging, and high-temperature resistant, and feeds the crushed waste into the plasma gasification melting furnace3. The pneumatic diaphragm pump 2 is used to directly transport the radioactive liquid waste to the plasma gasification melting furnace 3 . The feed device connected above the feed inlet of the plasma gasification melting furnace includes a connected feed bin and is provided with a corresponding control valve.

As shown in Figure 3, the plasma gasification melting furnace 3 comprises a furnace cover 301 and a furnace body 302, the furnace cover 301 is buckled on the upper end of the furnace body 302, and the furnace cover 301 is provided with a solid waste feed port 303 communicating with the furnace, Liquid waste feed port 304 and observation measurement window 305, solid waste feed port 303 is provided with feed bin 305 and control valve 306, feed bin 305 is a circular funnel and feed bin 305 lower end and solid waste feed port The upper end of 303 is fixedly connected, and the control valve 306 is arranged at the lower end of the feeding bin 305 for controlling the feeding amount.

The inner wall of the furnace body 302 is provided with a thermal insulation layer 311, the side wall of the furnace body 302 is provided with an air inlet hole 308, the other side wall of the furnace body 302 is provided with a synthesis gas outlet 309, and the furnace body 302 is provided with a Fire grate 312, the fire grate 312 is arranged horizontally and fixed on the inner wall of the furnace body 302 to divide the furnace into a gasification area 310 on the upper side of the fire grate and a melting area 313 on the lower side of the fire grate, and a melting pool crucible 314 is provided at the lower end of the melting area 313 The melting pool crucible 314 is set at the center of the lower end of the furnace body and is made of refractory material. There are two thermal plasma torches 315 inside the melting pool crucible 314, and the lower end of the melting pool crucible 314 is provided with a discharge channel penetrating the outside of the furnace body 302. Hole 316. One end of the thermal plasma torch 315 is arranged in the melting pool crucible 314 through the side wall of the furnace body 302 from the outside of the furnace body, and two thermal plasma torches 315 are symmetrically arranged on both sides of the furnace body 302 . An induction coil 318 is arranged around the discharge through hole 316 , and a thermal valve 317 passes through the lower end of the furnace shaft 302 and is arranged around the discharge through hole 316 and outside the induction coil 318 . The opening and closing of the thermal valve 317 is controlled by the induction heating of the intermediate frequency power supply. The lower end of the thermal valve 317 is docked with a molten glass body receiver 4 for carrying the molten glass body and transporting it to the storage room.

The thermal plasma torch 315 is a non-transferred arc DC plasma torch, using nitrogen and air as the plasma working medium. The DC plasma torches are evenly distributed above the crucible side of the plasma gasification melting furnace, and the axial direction forms an angle of less than 90° with the central axis of the furnace body. The number of DC plasma torches used is 2, Connect the plasma control power supply externally. A plurality of thermocouples are arranged in the axial direction of the plasma gasification melting furnace for monitoring the axial temperature distribution in the furnace. The discharge through hole of the thermal valve 317 is made of high-power graphite, surrounded by an induction coil, and externally connected with an intermediate frequency power supply.

The plasma gasification melting furnace in this system is a fully enclosed device, which operates under a slight negative pressure working condition, and the whole process of the system device is automatically controlled and operated. The treated low and medium radioactive waste reacts in the gasification zone of the plasma gasification melting furnace, and the synthesis gas produced by the reaction is sent into the combustion chamber, and the ash and glass forming agent produced are produced after the high-temperature melting treatment of thermal plasma in the melting zone. It can effectively capture radionuclides, heavy metals or other toxic and harmful substances, and the molten glass body with extremely low leaching rate.

A mobile small-scale low-to-medium radioactive waste gasification melting treatment method, comprising the following steps:

Step 1: The low and medium radioactive labor protection products are crushed by the crusher and sent to the plasma gasification melting furnace by the shaftless screw feeder, and the low and medium radioactive liquid waste is sent into the plasma gasification melting furnace through the pneumatic diaphragm pump;

Step 2: Low and medium radioactive labor protection products and low and medium radioactive liquid waste enter the gasification zone of the plasma gasification melting furnace, and gasification reaction occurs at 1000-1200 ° C to form synthesis gas and ash;

Step 3: The generated synthesis gas is sent to the combustion chamber by the induced draft fan for combustion treatment to form harmless small molecular gas, and the ash is collected and returned to the plasma gasification melting furnace for processing;

Step 4: Ash and slag fall into the melting zone of the plasma gasification melting furnace for melting, capture and solidify radionuclides under the condition of 1200-1400°C, and finally generate harmless molten glass body, which will be cooled in 200L concrete steel barrel sealed storage;

Step 5: The high-temperature flue gas generated in step 3 is sent to the subsequent flue gas purification treatment system for treatment, and discharged after reaching the standard. The generated fly ash is collected and sent to the plasma gasification melting furnace for treatment.

The high-temperature flue gas from the combustion chamber reduces the temperature to 700°C through direct heat exchange with the cold air, and then passes through the three-stage high-temperature ceramic filter to deeply capture the particulate matter, and the dust-removed flue gas exchanges heat with the cold air again, The temperature of the flue gas is rapidly cooled to 200±20°C through excess air, and then enters the activated carbon adsorption device for gas radionuclide removal, and then enters the deacidification system to treat the acidic substances in the flue gas, and then uses the HEPA high-efficiency air filter to treat the acidic substances in the flue gas. The fine dust in the flue gas is intercepted again, and finally the flue gas is sent into the chimney through the induced draft fan and discharged into the atmosphere.

This method adopts automatic operation in the whole process, and the solid waste molten glass produced by the receiver is cooled and stored in a 200L concrete steel drum, and the waste gas produced is discharged after being monitored online by CEMS to meet the comprehensive emission standard of air pollutants To the atmosphere, the wastewater in the whole process meets the radiation protection regulations of nuclear power plants and discharges up to standard.

The invention utilizes the characteristics of high energy density of thermal plasma and can process wastes with high melting points, and sends the synthesis gas formed after the gasification reaction of low and medium radioactive wastes in the gasification zone into the combustion chamber for combustion to form small molecular harmless substances , the generated ash and vitreous body forming agent are melted in the melting zone, and the radionuclide is stably fixed in the molten glass body, and the generated flue gas is purified to meet the emission requirements of the air quality standard. Compared with the existing technology, it can achieve a volume reduction ratio of more than 95%, greatly reducing the storage space for radioactive waste treatment, and using plasma gasification melting furnace to process radioactive waste, effectively reducing processing costs and risks, and facilitating flexible control and monitoring. The invention provides an environment-friendly system and method for treating low- and medium-radioactive solid waste with good volume reduction effect, high safety and reliability, good nuclide stability, and high system process integration, which meets the requirements of the national treatment of low- and medium-radioactive solid waste. The standard of treatment to achieve the purpose of minimization and stabilization of low and medium radioactive waste.

The above content described in this specification is only an illustration of the present invention. Those skilled in the technical field to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, as long as they do not deviate from the content of the present invention specification or exceed the scope defined in the claims, all should Belong to the protection scope of the present invention.

Claims (9)

1. cool waste gasification and melting processing system in a kind of movable small, it is characterised in that: comprising crusher, pneumatically Diaphragm pump, plasma gasification melting furnace, melten glass body receiver, combustion chamber, level-one direct heat exchanger, ceramic filter, Second level direct heat exchanger, activated carbon adsorber, depickling scrubbing tower, high efficiency particle air filter, chimney and mobile device, crusher go out Material mouth is connect by shaftless screw feeder with plasma gasification melting furnace feed inlet, and the output end of pneumatic diaphragm pump passes through pipe Road is connect with the feed inlet of plasma gasification melting furnace, and plasma gasification melting furnace is arranged in melten glass body receiver The syngas outlet of the outlet of lower end lime-ash, plasma gasification melting furnace is connect by pipeline with combustion chamber import, and combustion chamber goes out Mouth is connect by pipeline with level-one direct heat exchanger entrance, and the outlet of level-one direct heat exchanger passes through pipeline and ceramic filter entrance Connection, ceramic filter outlet are connected by second level direct heat exchanger entrance, and the outlet of second level direct heat exchanger passes through pipeline and work Property the connection of charcoal adsorption column inlet, activated carbon adsorber outlet connect by pipeline with depickling washing tower inlet, and depickling scrubbing tower goes out Mouthful connect with high efficiency particle air filter entrance by pipeline, high efficiency particle air filter is exported and is connect with chimney, crusher, pneumatically every Membrane pump, plasma gasification melting furnace, melten glass body receiver, combustion chamber, level-one direct heat exchanger, ceramic filter, two Grade direct heat exchanger, activated carbon adsorber, depickling scrubbing tower, high efficiency particle air filter and chimney are respectively provided on the mobile apparatus.

2. cool waste gasification and melting processing system in movable small described in accordance with the claim 1, it is characterised in that: The plasma gasification melting furnace includes bell and shaft, and bell be located in shaft upper end, is provided on bell and connects with burner hearth Logical solid waste feed inlet and liquid wastes feed inlet, is provided with insulating on shaft inner wall, on the side wall of shaft side It is provided with air introduction hole, syngas outlet is provided on the side wall of the shaft other side, fire grate is provided in shaft, fire grate level is set The melting zone set and be fixed on the downside of the gasification zone that burner hearth is divided on the upside of fire grate on shaft inner wall and fire grate, melting zone lower end It is provided with molten bath crucible, two thermal plasma torch are provided in the crucible of molten bath, molten bath the lower end of the crucible is provided with and passes through on the outside of shaft The discharge through-hole worn.

3. cool waste gasification and melting processing system in movable small according to claim 2, it is characterised in that: It is additionally provided on the bell and observes and measures window.

4. cool waste gasification and melting processing system in movable small according to claim 2, it is characterised in that: Feeding warehouse and control valve are provided on the solid waste feed inlet, feeding warehouse is for round funnel and feeding warehouse lower end and admittedly Body feeds waste mouth upper end is fixedly connected, and control valve setting is in feeding warehouse lower end for controlling inventory.

5. cool waste gasification and melting processing system in movable small according to claim 2, it is characterised in that: Described thermal plasma torch one end passes through shaft side wall on the outside of shaft and is arranged in the crucible of molten bath, two thermal plasma torch pair Claim to be arranged in shaft two sides.

6. cool waste gasification and melting processing system in movable small according to claim 2, it is characterised in that: Induction coil is furnished with around the discharge through-hole, thermal valve is through shaft lower end and is circumferentially positioned at discharge through-hole and induction coil Outside.

7. cool waste gasifying and melting process for the treatment of in a kind of movable small, it is characterised in that comprise the steps of:

Step 1: low middle radioactivity appliances for labor protection are sent into plasma gasification by shaftless screw feeder after crusher crushes and are melted Melt furnace, low middle radioactive liquid waste is pumped into plasma gasification melting furnace by pneumatic diaphragm；

Step 2: low middle radioactivity appliances for labor protection and low middle radioactive liquid waste enter gasification in plasma gasification melting furnace Area occurs gasification reaction under the conditions of 1000-1200 DEG C and forms synthesis gas and lime-ash；

Step 3: the synthesis gas of generation is sent into combustion chamber through air-introduced machine and carries out burning processing, forms innoxious micro-molecular gas；

Step 4: the melting zone that lime-ash is fallen into plasma gasification melting furnace is melted, and is caught under the conditions of 1200-1400 DEG C Collect and solidify radionuclide and ultimately generate innoxious melten glass body, is deposited after cooling in the sealing of 200L concrete steel drum Storage；

Step 5: the high-temperature flue gas that step 3 generates is sent into subsequent system for cleaning fume processing, discharges after up to standard.

8. cool waste gasifying and melting process for the treatment of in movable small according to claim 7, it is characterised in that: The step 5 is specially to cool the temperature to 700 DEG C by directly exchanging heat with cold air from the high-temperature flue gas that combustion chamber comes out, so Depth trapping is carried out to particulate matter by three-level High Temperature Ceramic Filter afterwards, the flue gas after dedusting is changed with cold air again Heat enters activated carbon adsorption device and carries out gaseous radioactivity after flue-gas temperature is quenched to 200 ± 20 DEG C by excessive air Nucleic removing, is handled the acidic materials in flue gas subsequently into deacidification system, then utilizes HEPA high-efficiency air filtering Device carries out intercept process again to the fine solid particle in flue gas, and last flue gas is sent into chimney by air-introduced machine and is discharged in atmosphere.

9. cool waste gasifying and melting process for the treatment of in movable small according to claim 7, it is characterised in that: The flying dust generated in the step 5 is unified after collecting to be sent into the processing of plasma gasification melting furnace.