Rear-end solid phosphorus incineration method and system for radioactive phosphorus-containing organic waste liquid

Abstract

The invention relates to a rear-end solid phosphorus incineration method and system for radioactive phosphorus-containing organic waste liquid, and the method comprises the steps that kerosene is added into the radioactive phosphorus-containing organic waste liquid to adjust the viscosity and the total heat value of feed liquid, the feed liquid meeting the conveying requirement and the incineration heat value requirement is prepared, and the feed liquid is incinerated in an incinerator; the incinerated flue gas is input into an alkali liquor quench cooler to be cooled and neutralized to fix phosphorus; the alkali liquor is a sodium carbonate solution; and inputting the cooled and phosphorus-fixed flue gas into a flue gas filter for filtering, and capturing phosphate particles generated by neutralization. According to the method, the radioactive phosphorus-containing organic waste liquid can be effectively treated by means of rear-end phosphorus fixation, corrosion of phosphoric acid to pipelines and equipment is reduced, and secondary waste liquid cannot be generated. In the bag filter, the settling of large-particle phosphate / pyrophosphate is realized by reducing the flow rate of flue gas, and other radioactive smoke dust is carried in the process and is captured by the bag filter.

Description

Technical Field

[0001] The invention relates to the technical field of radioactive phosphorus-containing organic waste liquid treatment, and in particular to a back-end phosphorus-fixing incineration method and system for radioactive phosphorus-containing organic waste liquid. Background Art

[0002] With the development of social economy and the transformation of energy structure, the status of nuclear power and nuclear energy industry in energy supply has become increasingly prominent. As a clean and efficient form of energy, nuclear power has great development potential. During the operation of reactors in nuclear power plants and other nuclear facilities, a considerable amount of spent fuel will be produced. Since there are many unconverted nuclides, transuranic elements and fragment elements in spent fuel, the reprocessing of spent fuel is crucial to the development of the entire nuclear industry. In the process of spent fuel reprocessing, both the mature Purex extraction process and the Thorex process use TBP as the extractant to extract from nitric acid solution; Tsinghua University has developed a high-level waste liquid extraction and separation technology with TRPO process as the core, and the extractant used is TRPO. After extraction with extractants (such as TBP, TRPO and CMPO, etc.), a distillation residue of radioactive phosphorus-containing organic waste liquid will be produced. The unified storage of these organic waste liquids has great uncertainty in viscosity, composition and radioactivity, and the properties change after long-term storage, which will also increase the difficulty of subsequent treatment and disposal.

[0003] For phosphorus-containing substances like TRPO, the phosphorus element can easily produce phosphoric acid and other substances that corrode equipment pipelines. The phosphorus removal and phosphorus fixation rate at the front end is low and cannot meet the phosphorus fixation requirements. Summary of the invention

[0004] The invention discloses a back-end phosphorus-fixing incineration method and system for radioactive phosphorus-containing organic waste liquid, aiming to solve the technical problems existing in the prior art.

[0005] Specifically, the present invention provides a back-end phosphorus-fixing incineration method and system for radioactive phosphorus-containing organic waste liquid, comprising:

[0006] By adding kerosene to the radioactive phosphorus-containing organic waste liquid to adjust the viscosity of the liquid and the overall calorific value of the liquid, a liquid that meets the transportation requirements and the calorific value requirements of the incineration is obtained, and the liquid is incinerated in an incinerator;

[0007] The flue gas after incineration is input into an alkali liquid quencher for cooling and neutralizing the fixed phosphorus; the alkali liquid is a sodium carbonate solution;

[0008] The flue gas after cooling and phosphorus fixation is input into the flue gas filter for filtration to capture the phosphate particles generated by neutralization.

[0009] As a preferred technical solution, radioactive phosphorus-containing organic waste liquid enters through a waste liquid inlet arranged at the top of the incinerator. A first compressed air inlet is also arranged at the top of the incinerator. Compressed air enters the furnace of the incinerator through the first compressed air inlet and mixes with the radioactive phosphorus-containing organic waste liquid. An ignition device is also arranged at the top of the incinerator. The radioactive phosphorus-containing organic waste liquid and compressed air can be ignited by the ignition device when entering the furnace.

[0010] As a preferred technical solution, the incinerator includes an auxiliary combustion device, which includes an auxiliary burner and a thermocouple arranged on the side wall of the incinerator. The auxiliary burner and the thermocouple are embedded in the furnace of the incinerator, and a temperature sensor is provided on the thermocouple.

[0011] As a preferred technical solution, the auxiliary burner is turned on to preheat the furnace. After preheating to a temperature suitable for combustion of the mixed organic waste liquid by observing the temperature feedback information of the thermocouple, the auxiliary burner is turned off to complete the preheating.

[0012] As a preferred technical solution, the auxiliary combustion device also includes a secondary air port. During the combustion stage, the incinerator adjusts the air volume of the secondary air port according to the temperature feedback signal of the thermocouple to ensure sufficient combustion of the radioactive organic waste liquid in the furnace.

[0013] As a preferred technical solution, a first flue gas outlet is provided at the bottom of the incinerator, and a first flue gas inlet is provided at the bottom of the alkali liquid quench cooler. The first flue gas outlet is connected to the first flue gas inlet, and the flue gas after combustion enters the alkali liquid quench cooler through the first flue gas outlet and the first flue gas inlet.

[0014] As a preferred technical solution, the alkali liquid quench cooler is provided with a steel shell layer, a heat-insulating material and a stainless steel plate layer in sequence from the inside to the outside, and can withstand a temperature of more than 600°C.

[0015] As a preferred technical solution, the alkali liquid quench cooler includes an alkali liquid inlet and a second compressed air inlet arranged at the top of the alkali liquid quench cooler body, a first flue gas inlet arranged at the bottom of the alkali liquid quench cooler body, and a second flue gas outlet arranged at the neck of the alkali liquid quench cooler body.

[0016] As a preferred technical solution, the flue gas filter is a bag filter, the alkali liquid quencher is connected to the bag filter, the bag filter includes a filter bag, and the filter bag is made of PTFE film and can withstand temperatures above 200°C.

[0017] As a preferred technical solution, the incinerator, alkali liquid quencher and bag filter are vertical structures.

[0018] The technical solution adopted by the present invention can achieve at least one of the following beneficial effects:

[0019] 1. The present invention can effectively treat radioactive phosphorus-containing organic waste liquid by means of back-end phosphorus fixation. The invention not only reduces the corrosion of phosphoric acid to pipelines and equipment, but also does not generate secondary waste liquid.

[0020] 2. The flue gas generated by the incineration of the present invention contains a large amount of phosphate. In the bag filter, the large-particle phosphate / pyrophosphate is precipitated by reducing the flue gas flow rate, and other radioactive smoke is carried in the process and captured by the bag filter. Most of the salt and part of the radioactive smoke are removed at the back end.

[0021] 3. The incinerator used in the present invention adopts an integrated design in which the auxiliary burner is embedded and fixedly installed on the side wall of the furnace. There is no need to rely on an external independent auxiliary preheating incinerator, which shortens the preheating time of the incinerator. At the same time, the structure is simple, and the entire organic waste liquid incineration treatment can be completed by a single person electronically controlled, which greatly reduces the work difficulty and workload and improves efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0023] Figure 1 This is a schematic flow chart of a back-end phosphorus-fixing incineration method for radioactive phosphorus-containing organic waste liquid proposed in Example 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the incineration process of phosphorus-containing organic waste liquid proposed in Example 1 of the present invention;

[0025] Figure 3 This is a schematic diagram of the high-temperature flue gas cooling and phosphorus fixation process proposed in Example 1 of the present invention;

[0026] Figure 4 This is a schematic diagram of a back-end phosphorus-fixing incineration system for radioactive phosphorus-containing organic waste liquid proposed in Example 2 of the present invention.

[0027] Description of reference numerals:

[0028] Incinerator 1; first flue gas outlet 101; first compressed air inlet 102; sight glass port 103; sight glass air port 104; combustion gas inlet 105; secondary air port 106; auxiliary burner 107; thermocouple 108; waste liquid inlet 109; ignition device 110; incineration nozzle 1101; shell 111; insulation material layer 112; furnace 113;

[0029] Alkali liquid quench cooler body 2; alkali liquid inlet 201; second compressed air inlet 202; first flue gas inlet 203; second flue gas outlet 204; steel shell layer 205, insulation material 206; stainless steel plate layer 207; inner cavity 208;

[0030] Bag filter 3; cylinder 301; second flue gas inlet 302. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0033] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment provides a back-end phosphorus-fixing incineration method for radioactive phosphorus-containing organic waste liquid, comprising:

[0036] Step S1: Incineration treatment of phosphorus-containing organic waste liquid: by adding kerosene to the radioactive phosphorus-containing organic waste liquid to adjust the viscosity of the liquid and the overall calorific value of the liquid, a liquid that meets the transportation requirements and the incineration calorific value requirements is obtained, and the liquid is incinerated in the incinerator 1.

[0037] Preferably, Figure 2 As shown, the incineration treatment of phosphorus-containing organic waste liquid specifically includes:

[0038] Step S101: Mixing and viscosity adjustment: adjusting the viscosity and overall calorific value of the feed liquid by adding kerosene to the radioactive phosphorus-containing organic waste liquid;

[0039] Step S102: Liquid incineration: Liquid enters from the organic waste liquid inlet 109, mixes with the high-pressure air sprayed from the first compressed air inlet, is sprayed into the furnace 113 of the incinerator 1 by the nozzle, and mixes with the combustion-supporting air to perform high-temperature combustion.

[0040] The operation process is as follows: first, turn on the auxiliary burner 107 to preheat the furnace 113 to 700-800°C, turn off the auxiliary burner 107, spray the feed liquid into the furnace 113, turn on the ignition device 110 to ignite the feed liquid, and burn the feed liquid. After the incineration is completed, the smoke after the incineration is output through the first smoke outlet 101 at the bottom of the incinerator 1.

[0041] Step S2: high-temperature flue gas cooling and phosphorus fixation: the flue gas after incineration is input into an alkaline liquid quencher for cooling and neutralization of phosphorus fixation, and the alkaline liquid is a sodium carbonate solution.

[0042] Preferably, Figure 3 As shown, specifically including:

[0043] Step S201: Initial cooling of flue gas: The flue gas after combustion is initially cooled, but the temperature must be at the dew point of phosphorus oxides. The flue gas output after incineration is introduced into the inner cavity 208 of the alkali liquid quench cooler through the first flue gas inlet 203.

[0044] Step S202: Cooling and phosphorus fixation: The flue gas after preliminary cooling enters the alkali liquid quencher, and the sprayed alkali liquid in the quencher cools the flue gas, causing a neutralization reaction to fix phosphorus and generate phosphate / pyrophosphate. Furthermore, the alkali liquid can be a sodium carbonate solution prepared from sodium carbonate, and the specific concentration depends on the phosphorus content of the incineration liquid. The alkali liquid can be stored in a water tank and enter through the alkali liquid inlet 201. The second compressed air inlet is fed with compressed air, and the alkali liquid is injected into the inner cavity 208 of the alkali liquid quencher through the nozzle for cooling and phosphorus fixation.

[0045] Preferably, the alkali liquid is sprayed into the inner cavity 208 of the alkali liquid quencher through a nozzle, and the alkali liquid is in a spray form in the inner cavity 208 of the alkali liquid quencher. The nozzle is a double-flow atomizing nozzle made of stainless steel.

[0046] The alkali liquid quench cooler is a vertical structure. Furthermore, the alkali liquid quench cooler is provided with a steel shell layer 205, a heat-insulating material 206 and a stainless steel plate layer 207 in sequence from the inside to the outside, and can withstand a temperature of more than 600°C.

[0047] Step S3: Flue gas filtration: The flue gas after cooling and phosphorus fixation enters the flue gas filter for filtration, and the phosphates generated by neutralization are captured. Preferably, the flue gas filter is a bag filter 3, and the alkali liquid quencher is connected to the bag filter 3, and the bag filter 3 is a vertical structure. The bag filter 3 includes a filter bag, which is made of PTFE film and can withstand temperatures above 200°C. The flue gas generated by incineration contains a large amount of phosphate. In the bag filter 3, large-particle phosphate / pyrophosphate precipitation is achieved by reducing the flue gas flow rate, and other radioactive smoke is carried in the process and captured by the bag filter 3.

[0048] By adding a back-end phosphorus fixation method, a series of reactions occur, and phosphorus is removed without generating new waste, thereby better removing and collecting phosphorus.

[0049] Preferably, the flue gas filter is a bag filter 3, the alkali liquid quencher is connected to the bag filter 3, and the bag filter 3 is a vertical structure. The bag filter 3 includes a filter bag, which is made of PTFE film and can withstand temperatures above 200°C.

[0050] Example 2

[0051] like Figure 4 As shown, this embodiment provides a post-phosphorus fixation incineration system for radioactive phosphorus-containing organic waste liquid, which is used to implement a post-phosphorus fixation incineration method for radioactive phosphorus-containing organic waste liquid as in Example 1. The system includes an incinerator 1, an alkali liquid quencher and a flue gas filter.

[0052] Among them, the incinerator 1 includes an incinerator 1 body, a liquid inlet ignition device 110 arranged on the top of the incinerator 1 body, an auxiliary combustion device fixedly installed on the side wall of the incinerator 1 body, and a first flue gas outlet 101 arranged at the bottom of the incinerator 1; the incinerator 1 body includes a furnace 113 for providing an incineration space.

[0053] The liquid inlet ignition device 110 includes an organic waste liquid inlet 109, a first compressed air inlet 102 and an ignition device 110, which are located at the top center of the incinerator 1 body and are sequentially distributed. The organic waste liquid inlet 109 is used to introduce radioactive phosphorus-containing organic waste liquid. The organic waste liquid is a waste liquid whose viscosity is adjusted by kerosene. The first compressed air inlet 102 is used to introduce compressed air required for combustion. The radioactive phosphorus-containing organic waste liquid and the compressed air can be ignited by the ignition device 110 when entering the furnace 113.

[0054] Preferably, the ignition device 110 is inserted into the incinerator 1 at a certain angle to prevent flame backflow, enhance the fuel mixing effect, etc., thereby improving the stability of the ignition process and the overall incineration efficiency. Figure 4The incinerator 1 shown in the use state is oriented in accordance with the direction, and the incineration nozzle 1101 is located below the first compressed air inlet 102, and is connected to the first compressed air inlet 102 and the organic waste liquid inlet 109 respectively. The radioactive organic waste liquid and the air required for combustion are mixed in the incineration nozzle 1101 through the organic waste liquid inlet 109 and the first compressed air inlet 102, respectively, and are transported to the furnace 113 through the incineration nozzle 1101. Preferably, the incineration nozzle 1101 is a double-flow atomizing nozzle. Further preferably, the incineration nozzle 1101 is made of metal such as stainless steel.

[0055] Preferably, Figure 4 As shown, the auxiliary combustion device includes multiple thermocouples 108 and at least one auxiliary burner 107 embedded and fixedly mounted on the side wall of the incinerator 1 body. The multiple thermocouples 108 and at least one auxiliary burner 107 are respectively embedded in the furnace 113. The multiple thermocouples 108 are located on the same side of the side wall of the incinerator 1 body and are evenly distributed at different heights in the axial direction of the furnace 113. Temperature sensors are provided on the multiple thermocouples 108. At least one auxiliary burner 107 is located on the opposite side of the multiple thermocouples 108, and is turned on or off according to the temperature information of the temperature sensor to adjust the temperature in the furnace 113.

[0056] In the specific operation, the auxiliary burner 107 is turned on in advance to preheat the furnace 113 to 700-800°C, the auxiliary burner 107 is turned off, the feed liquid is sprayed into the furnace 113, the ignition device 110 is turned on to ignite the feed liquid, and the feed liquid is incinerated. Furthermore, the auxiliary combustion device also includes a sight glass port 103 and a sight glass air port 104, the sight glass air port 104 is fixedly mounted on the sight glass port 103, and the axial direction of the sight glass air port 104 is perpendicular to the axial direction of the sight glass port 103. At this time, the combustion flame in the furnace 113 can be observed through the sight glass port 103.

[0057] Preferably, the auxiliary combustion device further comprises a secondary air port 106 . During the combustion stage, the incinerator 1 adjusts the air volume of the secondary air port 106 according to the temperature feedback signal of the thermocouple 108 to ensure sufficient combustion of the radioactive organic waste liquid in the furnace 113 .

[0058] The alkali liquid quench cooler includes an alkali liquid quench cooler body 2, an alkali liquid inlet 201 and a second compressed air inlet 202 arranged at the top of the alkali liquid quench cooler body 2, a first flue gas inlet 203 arranged at the bottom of the alkali liquid quench cooler body 2, and a second flue gas outlet 204 arranged at the neck of the alkali liquid quench cooler body 2; the first flue gas outlet 101 is connected to the first flue gas inlet 203, and the flue gas after combustion enters the alkali liquid quench cooler through the first flue gas outlet 101 and the first flue gas inlet 203.

[0059] The flue gas filter is a bag filter 3, including a cylinder 301, a filter bag is arranged in the cylinder 301, a second flue gas inlet 302 is arranged in the cylinder 301, and a second flue gas outlet 204 is connected to the second flue gas inlet 302. After the flue gas after phosphorus fixation enters the bag filter 3, the flue gas flow rate is reduced to achieve the precipitation of large-particle phosphate / pyrophosphate, and other radioactive smoke is carried in the process and captured by the bag filter 3, and most of the salt and part of the radioactive smoke are removed at the rear end.

[0060] Preferably, the incinerator 1, the alkali liquid quencher and the flue gas filter are all vertical structures.

[0061] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid, characterized in that: include: Adding kerosene to the radioactive phosphorus-containing organic waste liquid to adjust the viscosity of the liquid and the overall calorific value of the liquid, thereby obtaining a liquid that meets the transportation requirements and the calorific value requirements of incineration, and incinerating the liquid in an incinerator; The flue gas after incineration is input into an alkali liquid quencher for cooling and neutralizing the fixed phosphorus; the alkali liquid is a sodium carbonate solution; The flue gas after cooling and phosphorus fixation is input into the flue gas filter for filtration to capture the phosphate particles generated by neutralization.

2. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 1, characterized in that: The radioactive phosphorus-containing organic waste liquid enters through the waste liquid inlet arranged at the top of the incinerator. The top of the incinerator is also provided with a first compressed air inlet. The compressed air enters the furnace of the incinerator through the first compressed air inlet and mixes with the radioactive phosphorus-containing organic waste liquid. The top of the incinerator is also provided with an ignition device. The radioactive phosphorus-containing organic waste liquid and compressed air can be ignited by the ignition device when entering the furnace.

3. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 1, characterized in that: The incinerator comprises an auxiliary combustion device, which comprises an auxiliary burner and a thermocouple arranged on the side wall of the incinerator. The auxiliary burner and the thermocouple are embedded in the furnace of the incinerator, and a temperature sensor is arranged on the thermocouple.

4. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 3, characterized in that: The auxiliary burner is turned on to preheat the furnace, and after preheating to a temperature suitable for combustion of the mixed organic waste liquid by observing the temperature feedback information of the thermocouple, the auxiliary burner is turned off to complete the preheating.

5. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 4, characterized in that: The auxiliary combustion device also includes a secondary air port. During the combustion stage, the incinerator adjusts the air volume of the secondary air port according to the temperature feedback signal of the thermocouple to ensure sufficient combustion of the radioactive organic waste liquid in the furnace.

6. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 1, characterized in that: A first flue gas outlet is provided at the bottom of the incinerator, and a first flue gas inlet is provided at the bottom of the alkali liquid quencher. The first flue gas outlet is connected to the first flue gas inlet, and the flue gas after combustion enters the alkali liquid quencher through the first flue gas outlet and the first flue gas inlet.

7. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 6, characterized in that: The alkali liquid quench cooler is provided with a steel shell layer, a heat-insulating material and a stainless steel plate layer in sequence from the inside to the outside, and can withstand a temperature of more than 600°C.

8. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 7, characterized in that: The alkali liquid quench cooler comprises an alkali liquid inlet and a second compressed air inlet arranged at the top of the alkali liquid quench cooler body, a first flue gas inlet arranged at the bottom of the alkali liquid quench cooler body, and a second flue gas outlet arranged at the neck of the alkali liquid quench cooler body.

9. The method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to claim 1, characterized in that: The flue gas filter is a bag filter, the alkali liquid quench cooler is connected to the bag filter, the bag filter comprises a filter bag, and the filter bag is made of PTFE film and can withstand a temperature of more than 200°C.

10. A method and system for the back-end phosphorus fixation incineration of radioactive phosphorus-containing organic waste liquid according to any one of claims 1 to 9, characterized in that: The incinerator, the alkali liquid quencher and the bag filter are vertical structures.

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