Process for treating radioactive TBP waste liquid by adopting water vapor plasma

Abstract

The invention discloses a process for treating radioactive TBP waste liquid by adopting water vapor plasma, and relates to the technical field of radioactive waste treatment processes. The treatment process comprises the following steps that air or nitrogen is adopted as starting carrier gas, and the starting carrier gas enters the root of a cathode from a starting gas pipe; the power supply electrifies the cathode and the anode of the plasma torch, and adjusts the current, the voltage and the starting gas volume to enable the plasma torch to reach a stable working state; introducing water vapor to the root of the cathode; vaporizing the TBP waste liquid, mixing the TBP waste liquid with water vapor, and enabling the mixture to enter the root of the cathode through a water vapor pipe; the water vapor plasma high-temperature jet flow is sprayed out from the nozzle, a water vapor plasma arc containing the TBP waste liquid is formed and works stably, and the TBP waste liquid is decomposed in a discharge cavity in the plasma torch. The pyrolysis rate of the radioactive waste TBP reaches 99% or above, and the treated waste residues are stable.

Description

Technical Field

[0001] The invention relates to the technical field of radioactive waste treatment technology, and in particular to a technology for treating radioactive TBP waste liquid by using water vapor plasma. Background Art

[0002] At present, my country's uranium purification and spent fuel reprocessing mostly use the PUREX process to achieve U and Pu recycling. When using the PUREX process for spent fuel reprocessing, tributyl phosphate (TBP) is often used as an extractant and kerosene as a diluent. After repeated use, the TBP extractant is degraded by chemical and radiation effects, and its performance deteriorates, becoming a radioactive waste organic solvent (i.e., radioactive waste TBP). Radioactive waste TBP contains a variety of radioactive nuclides (such as U, Pu, etc.) and is one of the more difficult radioactive wastes produced by nuclear facilities. As a flammable organic solvent, long-term storage poses the risk of explosion and leakage. Therefore, seeking safe and feasible treatment technologies is an urgent problem to be solved in this field.

[0003] Incineration is a simple, efficient and feasible method for treating organic waste liquid. It can oxidize and decompose organic matter under high temperature conditions, and the organic matter removal rate can reach more than 99%. However, it requires strict control of the incineration process and has high requirements for tail gas treatment. At present, there are many research methods for the organic phase of radioactive waste TBP in the world. The more commonly used or studied methods include cement solidification, supercritical water oxidation technology, steam reforming, traditional air incineration, plasma treatment, etc. The cement solidification process is relatively simple, but the volume increase ratio is large, and the performance of the solidified body needs to be studied; the supercritical water oxidation technology has a large volume reduction ratio and a small amount of secondary waste, but it needs to be carried out under high temperature and high pressure conditions, with high equipment requirements, harsh operating conditions, serious corrosion of the reactor, and serious problems of reactor and pipeline blockage; the steam reforming method has a relatively low cost, but phosphoric acid is thermally condensed into polyphosphoric acid, which sticks to the filter and the pyrolysis furnace wall after evaporation, resulting in a decrease in the operating performance of the pyrolysis furnace. The traditional air incineration method completely destroys the organic phase and completely oxidizes the gas phase products, which can achieve a very high volume reduction ratio. However, the equipment used is large, the economic investment is high, the radioactive ash is seriously entrained in the tail gas, and the reaction process is slow. Summary of the invention

[0004] Based on the problems pointed out in the background technology that the current process equipment for treating radioactive TBP waste liquid is large in size, high in economic investment, serious entrainment of radioactive ash in tail gas, and slow reaction process rate, the purpose of the present invention is to provide a process for treating radioactive TBP waste liquid using water vapor plasma. In the process of treating ordinary low-radioactive miscellaneous dry waste, the process mixes TBP waste liquid into a plasma furnace for disposal, and the pyrolysis rate of radioactive waste TBP reaches more than 99%. The equipment is small in size, low in economic investment, fast in reaction rate, stable waste residue after treatment, and small in secondary waste output. The product is clean and has good operability, which not only ensures the effectiveness of engineering application, but also ensures the disposal safety of the products after participating in the reaction.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present application provides a process for treating radioactive TBP waste liquid using water vapor plasma, using a water vapor plasma torch for treatment;

[0007] The treatment process includes the following steps:

[0008] In the startup phase, air or nitrogen is used as the startup carrier gas, and the startup carrier gas enters the cathode root from the startup gas pipe;

[0009] The power supply energizes the cathode and anode of the plasma torch, and the two electrodes start arcing under high voltage. At this time, a plasma arc is generated. The current, voltage, and starting gas volume are adjusted to make the plasma torch reach a stable working state.

[0010] The water vapor which has passed through the heater and vaporized is introduced into the root of the cathode through the water vapor pipe;

[0011] The TBP waste liquid is introduced into the heater, vaporized and mixed with water vapor, and enters the root of the cathode through the water vapor tube; a high-temperature jet of high-enthalpy water vapor plasma is ejected from the nozzle, and a water vapor plasma arc containing TBP waste liquid is formed and works stably, and the TBP waste liquid is decomposed in the discharge chamber inside the plasma torch.

[0012] Furthermore, when the water vapor that has passed through the heater and vaporized is introduced into the root of the cathode through the water vapor pipe, the water vapor amount is first controlled, and then the water vapor amount is slowly increased and the air amount is slowly reduced, and finally 100% water vapor is reached, the air amount is reduced to zero, and the arc working state is stabilized.

[0013] Furthermore, when the TBP waste liquid is vaporized and mixed with water vapor, the amount of TBP waste liquid is controlled first, the amount of TBP waste liquid is slowly increased and the amount of water vapor is slowly reduced, and finally the designed ratio is reached.

[0014] Furthermore, the designed ratio of TBP waste liquid to water vapor is 1:4.

[0015] In a second aspect, the present application provides a treatment system for treating radioactive TBP waste liquid using water vapor plasma, comprising a plasma furnace and a second combustion chamber interconnected by a pipeline, wherein the plasma furnace comprises a vertical section and a horizontal section, and is arranged in an L shape; a No. 1 plasma torch is installed on the top of the horizontal section of the plasma furnace, and a No. 2 plasma torch is installed on the top of the second combustion chamber; the No. 1 plasma torch and the No. 2 plasma torch have the same structure, including a cathode and an anode, and a starting gas pipe and a water vapor pipe are installed at the connection between the cathode and the anode;

[0016] A feed inlet is provided at the top of the vertical section of the plasma furnace, and a plurality of first thermocouples are installed in the middle;

[0017] A glass melt overflow outlet is arranged above the side of the horizontal section of the plasma furnace, and a metal melt overflow outlet is arranged below the side.

[0018] Furthermore, after the material enters the vertical section of the plasma furnace from the feed port of the plasma furnace, a drying layer, a pyrolysis layer, a slag layer, a glass solution layer, and a metal solution layer are formed in sequence from top to bottom.

[0019] Furthermore, the plasma furnace uses high temperature resistant, corrosion resistant and fire resistant materials as the internal working layer.

[0020] Furthermore, an inclined section is provided on the right side of the furnace bottom of the plasma furnace.

[0021] Furthermore, a first central annular air inlet and a second central annular air inlet are provided in the middle of the secondary combustion chamber. In actual engineering applications, 4 to 6 annular air inlets can be provided as needed to improve the treatment effect.

[0022] By setting an air port in the middle of the secondary combustion chamber, the oxygen required for the combustion of the combustible components can be increased.

[0023] Furthermore, the pipeline is connected to a second thermocouple and an oxygen meter.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) Water vapor plasma is water vapor produced by the action of a strong electric field on water or an aqueous solution, which causes ionization, dissociation and excitation, and produces active components such as high-energy electrons, hydrogen ions, negative ions, H, O, and OH. Among them, the concentration of hydroxyl radicals produced by high-temperature strong oxidizing substances such as O and OH is much higher than that of non-water vapor low-temperature plasma of ordinary gas discharge, and has the characteristics of high reactivity. The enthalpy value of the high-temperature water vapor plasma produced is almost an order of magnitude higher than the plasma produced by the ionization of other gases such as oxygen, nitrogen and argon. At the same time, the high temperature of up to 5000°C inside the plasma torch can almost instantly decompose various organic components; therefore, this ultra-high enthalpy value, high temperature, and high activation characteristics can effectively improve the efficiency of TBP pyrolysis and gasification reaction inside the discharge chamber (up to more than 99%).

[0026] (2) Water vapor is used as the plasma working carrier. Compared with conventional air (or nitrogen) plasma, water vapor plasma does not produce secondary pollution such as nitrogen oxides. Especially for the Hainan nuclear power plasma project, according to the requirements of the "Hainan Island Ecological Environment Protection Regulations": the area is in an ecological tourism area, and all production and operation units must implement and meet the near-zero emission standards of pollutants in stages. Therefore, the zero nitrogen oxide generation characteristics of water vapor plasma are very suitable for the environmental protection requirements of the Hainan nuclear power project.

[0027] (3) Because TBP waste liquid contains a large amount of phosphorus, phosphorus will form volatile acidic oxides under high temperature conditions, which will cause severe corrosion to the subsequent system. Therefore, it is usually necessary to add a phosphorus fixer, and the process is relatively complicated. The high-temperature jet ejected by the water vapor plasma torch installed in the melting zone contains phosphorus contained in the TBP source item. This part can be solidified in the glass body through the glass solidification effect inside the molten pool, greatly alleviating the corrosiveness caused by phosphorus in the downstream and the disposal pressure of the exhaust system.

[0028] (4) The high-temperature jet ejected by the water vapor plasma torch installed in the melting zone can enhance the gas volume stirring effect of the molten pool in the melting zone and make up for the disadvantage of uneven temperature of the molten pool. At the same time, the heat of TCP pyrolysis can be provided to the molten pool, better melt the glass body and reduce the energy consumption of the system.

[0029] (5) In the secondary combustion chamber, the high-temperature and high-enthalpy water vapor plasma generated by the plasma torch can not only completely burn the combustible components in the synthesis gas, but also the hydrogen source in the active groups generated by the water vapor plasma can inhibit the formation of gaseous sulfur, phosphorus and free chlorine, thereby inhibiting the production of dioxins to a certain extent and reducing the concentration of pollutants.

[0030] (6) Through the cold top effect of the gasification zone, while controlling the exhaust temperature of a combustion chamber, a large amount of volatile radionuclides such as Cs contained in the volatilized organic waste liquid settle, and then re-enter the melting zone for glass solidification. In this way, more radionuclides are solidified inside the glass body instead of volatilizing into the flue gas, thereby improving the safety of the system and reducing the pressure of exhaust gas adsorbed radionuclides. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0032] Figure 1 It is a schematic diagram of the structure of the No. 1 plasma torch and the No. 2 plasma torch in the present invention;

[0033] Figure 2 The schematic diagram is a structural diagram of a treatment system for treating radioactive TBP waste liquid using water vapor plasma in the present invention.

[0034] Reference numerals:

[0035] 1-plasma furnace, 2-feeding port, 3-refractory material, 4-smoke exhaust pipe, 5-No. 1 plasma torch, 6-glass melt overflow outlet, 7-metal melt overflow outlet, 8-first thermocouple, 9-drying layer, 10-pyrolysis layer, 11-oxidation layer, 12-slag layer, 13-glass solution layer, 14-metal solution layer, 15-smoke exhaust port, 16-second thermocouple, 17-second combustion chamber, 18-No. 1 middle annular air inlet, 19-ash discharge port, 20-No. 2 plasma torch, 21-oxygen meter, 22-No. 2 middle annular air inlet, 23-nozzle, 24-starting gas pipe, 24-steam pipe, 25-cathode, 26-anode. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0037] The following detailed description specifically discloses the implementation methods of the compatibility system, treatment device and method for treating radioactive waste of the present application with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0038] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range.

[0039] In addition, the terms "number one" and "number two" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "number one" and "number two" may explicitly or implicitly include at least one of the features.

[0040] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0041] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0042] Unless otherwise specified, the terms "include" and "comprising" mentioned in this application may be open-ended or closed-ended. For example, the terms "include" and "comprising" may mean that other substances not listed may also be included or only the listed substances may be included.

[0043] Example 1

[0044] like Figure 1 As shown, this embodiment provides a process for treating radioactive TBP waste liquid using water vapor plasma, using a water vapor plasma torch for treatment.

[0045] S1. First, in the starting stage, air or nitrogen is used as the starting carrier gas, and the starting gas enters the root of the cathode 25 from the starting gas pipe 24 according to the set flow pressure.

[0046] S2. The power supply energizes the cathode 25 and the anode 26 of the plasma torch. The two electrodes arc under high voltage. At this time, a plasma arc is generated. The current, voltage and starting gas volume are adjusted to make the plasma torch reach a stable working state.

[0047] S3. The water vapor that has passed through the heater and vaporized is introduced into the root of the cathode 25 through the water vapor pipe 24. The water vapor dosage is controlled in the initial stage, and the water vapor dosage is slowly increased and the air volume is slowly reduced. At this stage, the electrical parameters need to be adjusted to match the arc characteristics, and finally 100% water vapor is achieved, the air volume is reduced to zero, and the arc working state is stabilized.

[0048] S4, the TBP waste liquid is introduced into the heater according to a certain ratio, and after vaporization, it is mixed with water vapor and enters the root of the cathode 25 through the water vapor pipe 24. In the initial stage, the amount of TBP waste liquid is controlled, the amount of TBP waste liquid is slowly increased and the amount of water vapor is slowly reduced. At this stage, the electrical parameters need to be adjusted to match the arc characteristics, and finally the designed ratio (1:4) is reached. At this point, a high-temperature and high-enthalpy water vapor plasma high-temperature jet is ejected from the nozzle 23, and the water vapor plasma arc containing TBP waste liquid is formed and works stably.

[0049] In this process, water vapor plasma is water vapor produced by strong electric field with water or aqueous solution, so that ionization, dissociation and excitation occur, and active components such as high-energy electrons, hydrogen ions, negative ions, H, O, OH, etc. are produced. Among them, the concentration of hydroxyl radicals produced by high-temperature strong oxidizing substances such as O and OH is much higher than that of non-water vapor low-temperature plasma of ordinary gas discharge, and has the characteristics of high reactivity. The enthalpy value of the high-temperature water vapor plasma produced is almost an order of magnitude higher than that of the plasma produced by the ionization of other gases such as oxygen, nitrogen and argon. At the same time, the high temperature of up to 5000℃ inside the plasma torch can almost instantly decompose various organic components. Therefore, this ultra-high enthalpy value, high temperature and high activation characteristics can effectively improve the efficiency of TBP pyrolysis and gasification reaction (up to more than 99%). Therefore, under the high temperature, high enthalpy and high catalytic conditions inside the discharge chamber of the plasma torch, TBP waste liquid is almost decomposed in seconds.

[0050] Example 2

[0051] like Figure 1 and Figure 2As shown, this embodiment provides a treatment system for treating radioactive TBP waste liquid using water vapor plasma, including a plasma furnace 1 and a second combustion chamber 17 interconnected by a pipeline, and a second thermocouple 16 and an oxygen meter 21 are connected to the pipeline; the plasma furnace 1 includes a vertical section and a horizontal section, which are arranged in an L shape. After the material enters the vertical section of the plasma furnace 1 from the feed port 2 of the plasma furnace 1, a drying layer 9, a pyrolysis layer 10, a slag layer 12, a glass solution layer 13, and a metal solution layer 14 are formed from top to bottom; the plasma furnace 1 uses a high temperature resistant, corrosion resistant, and refractory material 3 as an internal working layer; a No. 1 plasma torch 5 is installed on the top of the horizontal section of the plasma furnace 1, and a No. 2 plasma torch 20 is installed on the top of the second combustion chamber 17; the No. 1 plasma torch 5 and the No. 2 plasma torch 20 have the same structure, including a cathode 25 and an anode 26, and a starting gas pipe 24 and a water vapor pipe 24 are installed at the connection between the cathode 25 and the anode 26;

[0052] A feed port 2 is provided at the top of the vertical section of the plasma furnace 1, and a plurality of first thermocouples 8 are installed in the middle;

[0053] A glass melt overflow outlet 6 is provided above the side of the horizontal section of the plasma furnace 1, and a metal melt overflow outlet 7 is provided below the side;

[0054] An inclined section is provided on the right side of the furnace bottom of the plasma furnace 1;

[0055] A first central annular air inlet 18 and a second central annular air inlet 22 are provided in the middle of the secondary combustion chamber 17 .

[0056] The technical principles of the system are as follows:

[0057] a. First, the pre-treated ordinary low-radioactive miscellaneous dry waste (usually including PE, clothing, etc.) passes through the feeding device and enters the plasma furnace 1 from the top feeding port 2.

[0058] b. After the material falls into the vertical section of the plasma furnace 1 from the feed port 2, a drying layer 9 (200-400°C), a pyrolysis layer 10 (400-600°C), an oxidation layer 11 (600-1200°C), and a slag layer 12 (1000-1200°C) are formed in the vertical direction from top to bottom; the temperature varies from 400 to 1200°C from the upper surface to the high temperature section; three first thermocouples 8 are set in the vertical gasification section to measure the temperature of the above layers respectively; the entire plasma furnace 1 is operated under negative pressure.

[0059] c. In the vertical gasification section of the plasma furnace 1, during the pyrolysis and gasification reaction of the material, most of the organic matter is gasified and pyrolyzed into synthesis gas (the main components are CO+H2), and then this part of the gas is discharged from the exhaust pipe 4 of the plasma furnace 1 to the secondary combustion chamber 17.

[0060] d. The inorganic matter (bottom slag and ash) remaining after pyrolysis in the vertical gasification section falls to the bottom of the vertical section, and then enters the horizontal melting section of the plasma furnace 1. A No. 1 plasma torch 5 is arranged above the melting section; as shown in the description of Example 1, the plasma torch uses water vapor and TBP waste liquid as plasma carriers to work; the temperature of the plasma torch discharge chamber is as high as 5000°C, and the arc generated ionizes the water vapor to form a high-temperature jet (adjustable to 2000°C), which directly heats and melts the inorganic components (silicon calcium, etc.) coming from the vertical section, and then forms a glass solution layer. The small amount of metal components (iron, copper, etc.) contained in the treated radioactive waste have a relatively high density, and are also melted into a liquid state and then sink to the bottom to form a metal solution layer 14. This is the stratification phenomenon inside the molten pool.

[0061] e. Water vapor plasma is water vapor produced by the action of a strong electric field on water or an aqueous solution, which causes ionization, dissociation and excitation, and produces active components such as high-energy electrons, hydrogen ions, negative ions, H, O, and OH. Among them, the high-temperature strong oxidizing substances such as O and OH produce hydroxyl radicals at a concentration much higher than the non-water vapor low-temperature plasma of ordinary gas discharge, and have the characteristics of high reactivity. The enthalpy value of the high-temperature water vapor plasma produced is almost an order of magnitude higher than the plasma produced by the ionization of other gases such as oxygen, nitrogen and argon. At the same time, the high temperature of up to 5000°C inside the plasma torch can almost instantly decompose various organic components in TBP waste liquid; therefore, this ultra-high enthalpy value, high temperature, and high activation characteristics can effectively improve the efficiency of TBP pyrolysis and gasification reaction (up to more than 99%).

[0062] f. In the horizontal melting section, the high temperature and high enthalpy characteristics of water vapor plasma also have a good melting effect on the melting of molten inorganic ash. It can not only make it melt rapidly under high temperature conditions, but also safely handle most highly toxic substances, and finally form a glass body after melting.

[0063] g.TBP waste liquid contains a large amount of phosphorus, which will form volatile acidic oxides under high temperature conditions, which will cause severe corrosion to the subsequent system. Therefore, it is usually necessary to add a phosphorus fixer, and the process is relatively complicated. The high-temperature jet ejected by the water vapor plasma torch installed in the horizontal melting zone contains phosphorus contained in the TBP source item. This part can be solidified in the glass body through the glass solidification inside the molten pool, which greatly alleviates the corrosiveness caused by phosphorus in the downstream and the disposal pressure of the tail gas system.

[0064] h. Because the high-temperature jet ejected by the water vapor plasma torch has strong rigidity, the front end of the jet can be sprayed into the molten pool, which has a strong disturbing effect on it, can improve the fluidity inside the molten pool, make the mixing inside the molten pool more complete and the temperature field more uniform.

[0065] i. A glass melt overflow outlet 6 is provided on the left side of the molten pool, which is normally sealed by a plug. When the glass liquid layer formed by the melted slag inside the molten pool reaches a certain height and the liquid level in the molten pool exceeds the overflow outlet by a large margin, the plug is moved from the left side through the actuator to move it out of the overflow outlet. At this time, the overflow outlet is opened and the glass liquid flows out from the glass melt overflow outlet 6.

[0066] j. The slag usually contains a small amount of metal (iron, copper, etc.). This part of the metal liquid cannot form a glass body and usually accumulates at the bottom of the molten pool. After waiting for a certain period of time (such as about a month), the overflow outlet 7 of the molten metal is opened to drain the metal liquid at the bottom.

[0067] k. After the vitreous liquid flows out from the overflow outlet 6 of the molten glass, it is cooled to form a vitreous body after a water quenching process; the vitreous body after volume reduction and solidification is then transferred to the next cement solidification process.

[0068] l. TBP waste liquid contains a large amount of radioactive nuclides, especially Cs; most of the non-volatile nuclides (such as U and Pu) react with the molten pool and are solidified into the glass body during the process of the water vapor plasma jet in the molten section being sprayed into the molten pool. A small amount of volatile nuclides (such as Cs) directly enter the flue gas under high temperature conditions, but the flue gas generated in the horizontal section is continuously cooled down in the process of passing through the vertical gasification section from bottom to top (entering the slag layer 12, oxidation layer 11, pyrolysis layer 10, and drying layer 9 in sequence). The temperature of the drying layer 9 on the upper surface of the vertical gasification section is only about 400°C, forming an upper cold cap state; due to the cold cap principle (glass solidification maturation theory, which is not elaborated here), the volatile nuclide Cs is always trapped inside the plasma furnace 1, and volatile nuclides such as Cs are precipitated and then re-enter the melting zone for glass solidification, so that more volatile nuclides are solidified inside the glass body instead of volatilizing into the flue gas, thereby reducing the proportion of nuclides entering the secondary combustion chamber 17 and the subsequent exhaust system, reducing the pressure of the subsequent system, and improving the system safety.

[0069] m. The previous steps describe that after the radioactive waste is treated by the plasma furnace 1, most of the organic matter is gasified and decomposed to form synthesis gas and enter the secondary combustion chamber 17, and the remaining inorganic matter (slag and ash) is melted by the high temperature of the water vapor plasma to form a glass body, which is a safe and stable medium that solidifies radionuclides, heavy metals and harmful substances (phosphorus, etc.) inside the glass body, and preliminarily achieves the effect of harmless reduction of radioactive waste.

[0070] n. The gasification and decomposition of organic matter inside the plasma furnace 1 mainly forms synthesis gas (CO+H2), which enters the secondary combustion chamber 17 through the exhaust pipe 4 of the plasma furnace 1; a vertical hole is opened in the exhaust pipe 4 near the secondary combustion chamber 17 pipeline, and a thermocouple and an oxygen meter 21 are set, the purpose of which is to measure the inlet flue gas parameters of the secondary combustion chamber 17; generally, the outlet temperature of the plasma furnace 1 is 400°C, and the oxygen content is about 0.8-1%.

[0071] o. A No. 2 plasma torch 20 is arranged above the top of the second combustion chamber 17; the principle is the same as that of the No. 1 plasma torch 5; it directly burns the synthesis gas (CO+H2) from the plasma furnace 1 and burns out its combustible components. During use, the plasma technology, due to its high temperature and high enthalpy characteristics, can not only efficiently burn combustibles under the condition of water vapor as a carrier, but also produces almost no NO x At the same time, the active groups in the high-temperature jet of water vapor plasma contain some hydrogen sources, which can inhibit the formation of gaseous sulfur, phosphorus and free chlorine, and thus inhibit the production of dioxins to a certain extent and reduce the concentration of pollutants.

[0072] p. In the middle of the secondary combustion chamber 17, we set the first central annular air inlet 18 and the second central annular air inlet 22. The air inlet is opened horizontally in the middle of the secondary combustion chamber 17 to increase the oxygen required for the combustion of the combustible components; similarly, only two air inlets are marked on the figure, and in actual engineering use, 4 to 6 annular air inlets can be set as needed to improve the treatment effect.

[0073] q. Finally, the flue gas completely burned in the secondary combustion chamber 17 is discharged from the exhaust port 15 to the downstream exhaust gas treatment system; a small amount of ash generated in the process is regularly discharged through the ash discharge port 19 of the bottom secondary combustion chamber 17.

[0074] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for treating radioactive TBP waste liquid using water vapor plasma, characterized in that: Treatment was performed using a water vapor plasma torch; The treatment process includes the following steps: In the startup phase, air or nitrogen is used as a startup carrier gas, and the startup carrier gas enters the root of the cathode (25) from the startup gas pipe (24); The power supply energizes the cathode (25) and the anode (26) of the plasma torch, and the two electrodes arc under high voltage, at which time a plasma arc is generated, and the current, voltage, and starting gas volume are adjusted so that the plasma torch reaches a stable working state; The water vapor that has passed through the heater and vaporized is introduced into the root of the cathode (25) through the water vapor pipe (24); The TBP waste liquid is introduced into the heater, vaporized and mixed with water vapor, and enters the root of the cathode (25) through the water vapor pipe (24); a high-temperature jet of water vapor plasma is ejected from the nozzle (23), a water vapor plasma arc containing the TBP waste liquid is formed and operates stably, and the TBP waste liquid is decomposed in the discharge chamber inside the plasma torch.

2. A process for treating radioactive TBP waste liquid using water vapor plasma according to claim 1, characterized in that: When the water vapor that has passed through the heater and vaporized is introduced into the root of the cathode (25) through the water vapor pipe (24), the water vapor dosage is first controlled, and then the water vapor dosage is slowly increased and the air volume is slowly reduced, and finally 100% water vapor is reached, the air volume is reduced to zero, and the arc working state is stabilized.

3. The process for treating radioactive TBP waste liquid using water vapor plasma according to claim 1, characterized in that: When TBP waste liquid is vaporized and mixed with water vapor, the amount of TBP waste liquid is controlled first, the amount of TBP waste liquid is slowly increased and the amount of water vapor is slowly reduced, and finally the designed ratio is reached.

4. A process for treating radioactive TBP waste liquid using water vapor plasma according to claim 3, characterized in that: The designed ratio of TBP waste liquid to water vapor is 1:

4.

5. A treatment system for treating radioactive TBP waste liquid using water vapor plasma, characterized in that: The invention comprises a plasma furnace (1) and a second combustion chamber (17) which are interconnected through a pipeline, wherein the plasma furnace (1) comprises a vertical section and a horizontal section, which are arranged in an L shape; a first plasma torch (5) is installed on the top of the horizontal section of the plasma furnace (1), and a second plasma torch (20) is installed on the top of the second combustion chamber (17); the first plasma torch (5) and the second plasma torch (20) have the same structure, comprising a cathode (25) and an anode (26); a starting gas pipe (24) and a water vapor pipe (24) are installed at the connection between the cathode (25) and the anode (26); The top of the vertical section of the plasma furnace (1) is provided with a feed inlet (2), and a plurality of first thermocouples (8) are installed in the middle; A molten glass overflow outlet (6) is arranged above the side of the horizontal section of the plasma furnace (1), and a molten metal overflow outlet (7) is arranged below.

6. A treatment system for treating radioactive TBP waste liquid using water vapor plasma according to claim 5, characterized in that: After the material enters the vertical section of the plasma furnace (1) from the feed port (2) of the plasma furnace (1), a drying layer (9), a pyrolysis layer (10), a slag layer (12), a glass solution layer (13), and a metal solution layer (14) are formed in sequence from top to bottom.

7. A treatment system for treating radioactive TBP waste liquid using water vapor plasma according to claim 5, characterized in that: The plasma furnace (1) uses high temperature resistant, corrosion resistant and fire resistant materials (3) as the internal working layer.

8. A treatment system for treating radioactive TBP waste liquid using water vapor plasma according to claim 5, characterized in that: The right side of the furnace bottom of the plasma furnace (1) is provided with an inclined section.

9. A treatment system for treating radioactive TBP waste liquid using water vapor plasma according to claim 5, characterized in that: A first central annular air inlet (18) and a second central annular air inlet (22) are provided in the middle of the secondary combustion chamber (17).

10. A treatment system for treating radioactive TBP waste liquid using water vapor plasma according to claim 5, characterized in that: The pipeline is connected to a second thermocouple (16) and an oxygen meter (21).

Images