Radioactive liquid waste evaporation concentration system

Abstract

This invention discloses a radioactive waste liquid evaporation and concentration system, comprising a primary preheater including a first heat exchange channel and a second heat exchange channel; a secondary preheater including a first heat exchange channel and a second heat exchange channel, the first heat exchange channel being connected to the first heat exchange channel of the primary preheater; an evaporator including a first heat exchange channel and a second heat exchange channel, the inlet of the first heat exchange channel being connected to the outlet of the first heat exchange channel of the secondary preheater; a separation and purification unit, the inlet of which is connected to the outlet of the first heat exchange channel of the evaporator, the outlet of which is connected to the inlet of the second heat exchange channel, and the outlet of which is connected to the inlet of the second heat exchange channel of the secondary preheater; the bottom of the separation and purification unit is connected to the second heat exchange channel of the primary preheater. The system increases the output concentration and concentration factor of the evaporated concentrate, reduces energy consumption, and achieves efficient and stable evaporation.

Description

Technical Field

[0001] This invention belongs to the field of radioactive waste treatment technology, specifically relating to a radioactive waste liquid evaporation and concentration system. Background Technology

[0002] The treatment of radioactive liquid waste is an important part of radioactive waste management in the nuclear fuel field. The use of advanced liquid waste treatment technology can not only improve the treatment effect and reduce the environmental impact of radionuclide emissions, but also reduce the generation of secondary waste, thus achieving the goals of safety, efficiency and economy.

[0003] Evaporation concentration is a commonly used and effective method for treating radioactive waste, but it is also the main energy-consuming process. Traditional evaporation systems for radioactive waste generally use natural circulation single-effect evaporators with fresh external steam as the heat source. With technological advancements and the increasing demand for energy conservation and carbon reduction, natural circulation heat pump evaporation systems coupled with heat pump technology are gradually being applied.

[0004] The natural circulation evaporation process relies on the density difference between the heat exchange tubes of the evaporator and the material in the separation chamber as the driving force for circulation. It is difficult to achieve a high discharge concentration and concentration ratio, which increases the amount of water, energy consumption and treatment costs in the downstream process. In addition, the processing scale of a single set of equipment is limited, making it difficult to meet the large-scale treatment needs of waste liquid. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a radioactive waste liquid evaporation and concentration system to achieve efficient and stable evaporation treatment of radioactive waste liquid.

[0006] The technical solution adopted to solve the technical problem of this invention is to provide a radioactive waste liquid evaporation and concentration system, comprising: The primary preheater includes: a primary preheater body, a first heat exchange channel of the primary preheater disposed on the primary preheater body, and a second heat exchange channel of the primary preheater disposed on the primary preheater body, wherein radioactive waste liquid is introduced through the inlet of the first heat exchange channel of the primary preheater. The secondary preheater includes: a secondary preheater body, a first heat exchange channel of the secondary preheater disposed on the secondary preheater body, and a second heat exchange channel of the secondary preheater disposed on the secondary preheater body, wherein the inlet of the first heat exchange channel of the secondary preheater is connected to the outlet of the first heat exchange channel of the primary preheater. An evaporator includes: an evaporator body, a first heat exchange channel of the evaporator body disposed on the evaporator body, and a second heat exchange channel of the evaporator body disposed on the evaporator body, wherein the inlet of the first heat exchange channel of the evaporator body is connected to the outlet of the first heat exchange channel of the secondary preheater. The separator / purifier has its bottom inlet connected to the outlet of the first heat exchange channel of the evaporator, its top outlet connected to the inlet of the second heat exchange channel of the evaporator, and its outlet connected to the inlet of the second heat exchange channel of the secondary preheater. The evaporated condensate is discharged from the outlet of the second heat exchange channel of the secondary preheater. The bottom outlet of the separator / purifier is connected to the inlet of the first heat exchange channel of the evaporator.

[0007] Preferably, the separator includes: a separator body, a cyclone plate, a sieve plate, and a packed demister arranged from bottom to top within the separator body.

[0008] Preferably, the radioactive waste evaporation and concentration system further includes: The condensate tank includes: a condensate tank body, a first condensate tank inlet, a second condensate tank inlet, a first condensate tank gas outlet, and a condensate tank condensate outlet disposed on the condensate tank body. The first condensate tank inlet is connected to the outlet of the second heat exchange channel of the evaporator, and the condensate tank condensate outlet is connected to the inlet of the second heat exchange channel of the secondary preheater. The three-stage preheater includes: a three-stage preheater body, a first heat exchange channel of the three-stage preheater body, and a second heat exchange channel of the three-stage preheater body. The inlet of the first heat exchange channel is connected to the outlet of the first heat exchange channel of the second stage preheater, and the outlet of the first heat exchange channel is connected to the inlet of the first heat exchange channel of the evaporator. The first gas outlet of the condensate tank is connected to the inlet of the second heat exchange channel of the three-stage preheater, and exhaust gas is discharged through the second outlet of the second heat exchange channel of the three-stage preheater. The first outlet of the second heat exchange channel of the three-stage preheater is connected to the second inlet of the condensate tank. The non-condensable gas outlet of the second heat exchange pipe of the evaporator is connected to the connecting pipe between the first gas outlet of the condensate tank and the inlet of the second heat exchange channel of the three-stage preheater.

[0009] Preferably, the condensate tank further includes an electric heater disposed within the condensate tank body. The electric heater is used to heat the condensate water within the condensate tank body to generate steam, which is used to supplement heat during the system operation and start-up preheating stages.

[0010] Preferably, the radioactive waste evaporation and concentration system further includes: A condensate pump is installed on the connecting pipe between the condensate outlet of the condensate tank and the inlet of the second heat exchange channel of the secondary preheater.

[0011] Preferably, the radioactive waste evaporation and concentration system further includes: The exhaust gas condenser is connected to the second outlet of the second heat exchange channel of the three-stage preheater.

[0012] Preferably, the radioactive waste evaporation and concentration system further includes: The fifth switch valve is connected to the outlet of the first heat exchange channel of the tertiary preheater and the inlet of the first heat exchange channel of the evaporator, respectively. The sixth switch valve, the first forced circulation pump, and the seventh switch valve are connected in sequence. The seventh switch valve is connected to the outlet of the first heat exchange channel of the three-stage preheater, and the sixth switch valve is connected to the inlet of the first heat exchange channel of the evaporator. The eighth switch valve, the second forced circulation pump, and the ninth switch valve are connected in sequence. The ninth switch valve is connected to the outlet of the first heat exchange channel of the three-stage preheater, and the eighth switch valve is connected to the inlet of the first heat exchange channel of the evaporator.

[0013] Preferably, the first forced circulation pump is an axial flow pump or a mixed flow pump; The second forced circulation pump is either an axial flow pump or a mixed flow pump.

[0014] Compared to natural circulation, the radioactive waste liquid evaporation and concentration system in this embodiment adds a first forced circulation pump and a second forced circulation pump. Driven by the first and second forced circulation pumps, the liquid is forced to circulate at a set flow rate. Even when the system starts up, the material concentration increases, or the heat exchange temperature difference decreases, it can still maintain a high flow rate in the pipe and a good circulation flow state, achieving a high discharge concentration and concentration factor, and ensuring the evaporation treatment effect.

[0015] Preferably, the condensate tank further includes a second gas outlet for the condensate tank, which is connected to the inlet of the second heat exchange channel of the evaporator.

[0016] Preferably, the radioactive waste evaporation and concentration system further includes: The steam compressor is connected to the top outlet of the separator and purifier tower, and also to the inlet of the second heat exchange channel of the evaporator.

[0017] Preferably, the steam compressor is also connected to the condensate outlet of the condensate tank.

[0018] Preferably, the steam compressor is any one of a Roots-type steam compressor, a centrifugal steam compressor, or a screw steam compressor.

[0019] Preferably, the radioactive waste evaporation and concentration system further includes: A water spray regulating valve is installed on the connecting pipe between the condensate outlet of the condensate tank and the steam compressor. A reflux regulating valve is installed on the connecting pipe between the condensate outlet of the condensate tank and the reflux inlet at the top of the separator / purifier tower.

[0020] Preferably, the radioactive waste evaporation and concentration system further includes: A heat storage tank includes: a heat storage tank body, a first heat exchange channel disposed on the heat storage tank body, and a second heat exchange channel disposed on the heat storage tank body. The outlet of the second heat exchange channel is connected to the inlet of the second heat exchange channel of the primary preheater, the outlet of the second heat exchange channel of the primary preheater is connected to the inlet of the second heat exchange channel of the heat storage tank, the outlet of the first heat exchange channel of the heat storage tank is connected to the inlet of the separator / purifier tower, and the inlet of the first heat exchange channel of the heat storage tank is connected to the outlet of the separator / purifier tower.

[0021] Preferably, in the radioactive waste liquid evaporation and concentration system, the outlet of the second heat exchange channel of the heat storage tank is connected to the inlet of the second heat exchange channel of the heat storage tank.

[0022] Preferably, the radioactive waste evaporation and concentration system further includes: The system includes a concentrate pump, a first switch valve, and a second switch valve. The concentrate pump is installed on the connecting pipe between the inlet of the first heat exchange channel of the heat storage tank and the outlet of the separator / purifier tower. The concentrate pump is used to pump the concentrate flowing out of the outlet of the separator / purifier tower into the first heat exchange channel of the heat storage tank. The first switch valve is installed on the connecting pipe between the outlet of the first heat exchange channel of the heat storage tank and the inlet of the separator / purifier tower. The inlet of the concentrate discharge pipe is connected to the connecting pipe between the first switch valve and the outlet of the first heat exchange channel of the heat storage tank. The second switch valve is installed on the concentrate discharge pipe, which is used to discharge the concentrate. The system includes a heat medium circulation pump, a third switch valve, and a fourth switch valve. The heat medium circulation pump is installed on the connecting pipe between the outlet of the second heat exchange channel of the heat storage tank and the inlet of the second heat exchange channel of the first-stage preheater. The third switch valve is installed on the connecting pipe between the heat medium circulation pump and the inlet of the second heat exchange channel of the first-stage preheater. The fourth switch valve is installed on the connecting pipe between the heat medium circulation pump and the inlet of the second heat exchange channel of the heat storage tank.

[0023] Preferably, the evaporator is a shell-and-tube heat exchanger or a plate heat exchanger.

[0024] Preferably, the primary preheater is a shell-and-tube heat exchanger or a plate heat exchanger. The secondary preheater is a shell-and-tube heat exchanger or a plate heat exchanger. The tertiary preheater is either a shell-and-tube heat exchanger or a plate heat exchanger.

[0025] Preferably, the exhaust gas condenser is a shell-and-tube heat exchanger or a plate heat exchanger.

[0026] Preferably, the radioactive waste evaporation and concentration system further includes: The feed pump is installed on the feed pipe connected to the inlet of the primary preheater. The feed pipe is used to introduce the radioactive concentrate.

[0027] The radioactive waste liquid evaporation and concentration system of the present invention effectively improves the output concentration of the evaporation concentrate and the evaporation concentration ratio, reduces system energy consumption, and enables efficient and stable evaporation treatment of radioactive waste liquid. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the radioactive waste liquid evaporation and concentration system in Embodiment 2 of the present invention.

[0029] In the diagram: 1-Separator and purifier; 2-Evaporator; 3-Steam compressor; 4-First forced circulation pump; 5-Second forced circulation pump; 6-Condensate tank; 61-First inlet of condensate tank; 62-Second inlet of condensate tank; 63-First gas outlet of condensate tank; 64-Condensate outlet of condensate tank; 65-Second gas outlet of condensate tank; 7-Heat storage tank; 8-First stage preheater; 9-Second stage preheater; 10-Third stage preheater; 11-Tail gas condenser; 12-Feed pump; 13-Condensate pump; 14-Heat medium circulation pump; 15-Concentrate pump; 16-Water spray regulating valve; 17-Recirculation regulating valve; 18-First switching valve; 19-Second switching valve; 20-Third switching valve; 21-Fourth switching valve; 22-Fifth switching valve; 23-Sixth switching valve; 24-Seventh switching valve; 25-Eighth switching valve; 26-Ninth switching valve; 27-Lower circulation pipe; 28-Upper circulation pipe. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0032] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] Example 1

[0035] This embodiment provides a radioactive waste liquid evaporation and concentration system, including: The primary preheater includes: a primary preheater body, a first heat exchange channel of the primary preheater disposed on the primary preheater body, and a second heat exchange channel of the primary preheater disposed on the primary preheater body, wherein radioactive waste liquid is introduced through the inlet of the first heat exchange channel of the primary preheater. The secondary preheater includes: a secondary preheater body, a first heat exchange channel of the secondary preheater disposed on the secondary preheater body, and a second heat exchange channel of the secondary preheater disposed on the secondary preheater body, wherein the inlet of the first heat exchange channel of the secondary preheater is connected to the outlet of the first heat exchange channel of the primary preheater. An evaporator includes: an evaporator body, a first heat exchange channel of the evaporator body disposed on the evaporator body, and a second heat exchange channel of the evaporator body disposed on the evaporator body, wherein the inlet of the first heat exchange channel of the evaporator body is connected to the outlet of the first heat exchange channel of the secondary preheater. The separator / purifier has its bottom inlet connected to the outlet of the first heat exchange channel of the evaporator, its top outlet connected to the inlet of the second heat exchange channel of the evaporator, and its outlet connected to the inlet of the second heat exchange channel of the secondary preheater. The evaporated condensate is discharged from the outlet of the second heat exchange channel of the secondary preheater. The bottom of the separator / purifier is connected to the second heat exchange channel of the primary preheater, and its bottom outlet is connected to the inlet of the first heat exchange channel of the evaporator.

[0036] The radioactive waste liquid evaporation and concentration system of the present invention effectively improves the output concentration of the evaporation concentrate and the evaporation concentration ratio, reduces system energy consumption, and enables efficient and stable evaporation treatment of radioactive waste liquid.

[0037] Example 2

[0038] like Figure 1 As shown, this embodiment provides a radioactive waste liquid evaporation and concentration system, including: The primary preheater 8 includes: a primary preheater body, a primary preheater first heat exchange channel disposed on the primary preheater body, and a primary preheater second heat exchange channel disposed on the primary preheater body, wherein radioactive waste liquid is introduced through the inlet of the primary preheater first heat exchange channel. The secondary preheater 9 includes: a secondary preheater body, a first heat exchange channel of the secondary preheater disposed on the secondary preheater body, and a second heat exchange channel of the secondary preheater disposed on the secondary preheater body, wherein the inlet of the first heat exchange channel of the secondary preheater is connected to the outlet of the first heat exchange channel of the primary preheater. Evaporator 2 includes: evaporator body, evaporator first heat exchange channel disposed on evaporator body, and evaporator second heat exchange channel disposed on evaporator body, wherein the inlet of evaporator first heat exchange channel is connected to the outlet of secondary preheater first heat exchange channel; Separator 1 has its bottom inlet connected to the outlet of the first heat exchange channel of the evaporator, its top outlet connected to the inlet of the second heat exchange channel of the evaporator, and its outlet connected to the inlet of the second heat exchange channel of the secondary preheater. The evaporated condensate is discharged from the outlet of the second heat exchange channel of the secondary preheater. The bottom of the separator is connected to the second heat exchange channel of the primary preheater, and its bottom outlet is connected to the inlet of the first heat exchange channel of the evaporator.

[0039] The evaporator is a key heat exchange device in the system, used for heat exchange between the compressed secondary steam and the radioactive waste liquid to ensure continuous evaporation.

[0040] Preferably, the separator purifier 1 includes: a separator purifier body, a swirl plate, a sieve plate, and a packing demister arranged from bottom to top within the separator purifier body.

[0041] Separator 1 is used for the vapor-liquid separation of the vapor-liquid mixture generated by evaporation and for the deep purification of secondary steam. It adopts a combination of gravity, cyclone, and filtration separation methods. The vapor phase section of separator 1 is equipped with a cyclone plate, a sieve plate, and a packed demister from bottom to top to ensure a high purification effect.

[0042] Preferably, the radioactive waste evaporation and concentration system further includes: The condensate tank includes: a condensate tank body, a first condensate tank inlet 61 disposed on the condensate tank body, a second condensate tank inlet 62, a first condensate tank gas outlet 63, and a condensate tank condensate outlet 64. The first condensate tank inlet 61 is connected to the outlet of the second heat exchange channel of the evaporator, and the condensate tank condensate outlet 64 is connected to the inlet of the second heat exchange channel of the secondary preheater. The three-stage preheater 10 includes: a three-stage preheater body, a first heat exchange channel of the three-stage preheater body, and a second heat exchange channel of the three-stage preheater body. The inlet of the first heat exchange channel is connected to the outlet of the first heat exchange channel of the second stage preheater, and the outlet of the first heat exchange channel is connected to the inlet of the first heat exchange channel of the evaporator. The first gas outlet 63 of the condensate tank is connected to the inlet of the second heat exchange channel of the three-stage preheater. Exhaust gas is discharged through the second outlet of the second heat exchange channel of the three-stage preheater, and the first outlet of the second heat exchange channel is connected to the second inlet 62 of the condensate tank. The non-condensable gas outlet of the second heat exchange pipe of the evaporator is connected to the connecting pipe between the first gas outlet 63 of the condensate tank and the inlet of the second heat exchange channel of the three-stage preheater.

[0043] Preferably, the condensate tank 6 further includes an electric heater disposed within the condensate tank body. The electric heater is used to heat the condensate water within the condensate tank body to generate steam, which is used to supplement heat during the system operation and start-up preheating stages.

[0044] The condensate tank 6 is used for temporary storage of evaporated condensate, preferably a horizontal tank; the condensate tank 6 has a built-in electric heater, which can be used as an electric steam generator to supplement the system heat.

[0045] Preferably, the radioactive waste evaporation and concentration system further includes: The condensate pump 13 is installed on the connecting pipe between the condensate outlet 64 of the condensate tank and the inlet of the second heat exchange channel of the secondary preheater.

[0046] Preferably, the radioactive waste evaporation and concentration system further includes: The exhaust gas condenser 11 is connected to the second outlet of the second heat exchange channel of the three-stage preheater.

[0047] Preferably, the radioactive waste evaporation and concentration system further includes: The fifth switching valve 22 is connected to the outlet of the first heat exchange channel of the tertiary preheater and the inlet of the first heat exchange channel of the evaporator, respectively. The sixth switch valve 23, the first forced circulation pump 4, and the seventh switch valve 24 are connected in sequence. The seventh switch valve 24 is connected to the outlet of the first heat exchange channel of the three-stage preheater, and the sixth switch valve 23 is connected to the inlet of the first heat exchange channel of the evaporator. The eighth switch valve 25, the second forced circulation pump 5, and the ninth switch valve 26 are connected in sequence. The ninth switch valve 26 is connected to the outlet of the first heat exchange channel of the three-stage preheater, and the eighth switch valve 25 is connected to the inlet of the first heat exchange channel of the evaporator.

[0048] The first forced circulation pump 4 and the second forced circulation pump 5 provide driving force for the circulation of materials within the system.

[0049] The present invention involves two forced circulation pumps connected in parallel and serving as backups for each other, which facilitates the continuous operation of the system in the event of maintenance of the forced circulation pumps.

[0050] Preferably, the first forced circulation pump 4 is an axial flow pump or a mixed flow pump; The second forced circulation pump 5 is an axial flow pump or a mixed flow pump.

[0051] Preferably, the condensate tank further includes a second gas outlet 65, which is connected to the inlet of the second heat exchange channel of the evaporator.

[0052] Preferably, the radioactive waste evaporation and concentration system further includes: The steam compressor 3 is connected to the top outlet of the separator and purifier tower, and also to the inlet of the second heat exchange channel of the evaporator.

[0053] Steam compressor 3 is used to compress and increase the enthalpy of the purified secondary steam in order to achieve the purpose of recovering and reusing low-grade waste heat.

[0054] Preferably, the steam compressor 3 is also connected to the condensate outlet 64 of the condensate tank.

[0055] Preferably, the steam compressor 3 is any one of a Roots-type steam compressor, a centrifugal steam compressor, or a screw steam compressor.

[0056] Specifically, in this embodiment, the steam compressor 3 is a Roots-type steam compressor. Regarding the combination of steam compressors, the same type of compressor can be connected in series or parallel, or different types of compressors can be combined in series.

[0057] Preferably, the radioactive waste evaporation and concentration system further includes: A water spray regulating valve 16 is installed on the connecting pipe between the condensate outlet 64 of the condensate tank and the steam compressor 3. The reflux regulating valve 17 is installed on the connecting pipe between the condensate outlet 64 of the condensate tank and the reflux inlet at the top of the separator 1 tower.

[0058] Preferably, the radioactive waste evaporation and concentration system further includes: The heat storage tank 7 includes: a heat storage tank body, a first heat exchange channel of the heat storage tank disposed on the heat storage tank body, and a second heat exchange channel of the heat storage tank disposed on the heat storage tank body. The outlet of the second heat exchange channel of the heat storage tank is connected to the inlet of the second heat exchange channel of the primary preheater, the outlet of the second heat exchange channel of the primary preheater is connected to the inlet of the second heat exchange channel of the heat storage tank, the outlet of the first heat exchange channel of the heat storage tank is connected to the inlet of the separator / purifier tower, and the inlet of the first heat exchange channel of the heat storage tank is connected to the outlet of the separator / purifier tower.

[0059] The heat storage tank 7 is used to recover and store the waste heat of the high-temperature concentrate. The waste heat is stored in the heat storage tank 7 via a heat transfer medium for preheating the feed before system startup. The heat storage tank 7 contains heat exchange coils through which the high-temperature concentrate flows. Deionized water is preferred as the heat storage medium. Currently, radioactive waste evaporation systems typically use intermittent discharge of the concentrate; no feed is received during the discharge, making it impossible to recover the waste heat for preheating the feed liquid. By setting up the heat storage tank 7 to temporarily store some waste heat, it can be used for preheating the feed before the next system startup.

[0060] Preferably, in the radioactive waste liquid evaporation and concentration system, the outlet of the second heat exchange channel of the heat storage tank is connected to the inlet of the second heat exchange channel of the heat storage tank.

[0061] Preferably, the radioactive waste evaporation and concentration system further includes: The system includes a concentrate pump 15, a first switching valve 18, and a second switching valve 19. The concentrate pump 15 is installed on the connecting pipe between the inlet of the first heat exchange channel of the heat storage tank and the outlet of the separator / purifier tower. The concentrate pump 15 is used to pump the concentrate flowing out of the outlet of the separator / purifier tower into the first heat exchange channel of the heat storage tank. The first switching valve 18 is installed on the connecting pipe between the outlet of the first heat exchange channel of the heat storage tank and the inlet of the separator / purifier tower. The inlet of the concentrate discharge pipe is connected to the connecting pipe between the first switching valve 18 and the outlet of the first heat exchange channel of the heat storage tank. The second switching valve 19 is installed on the concentrate discharge pipe, which is used to discharge the concentrate. The heat medium circulation pump 14, the third switch valve 20, and the fourth switch valve 21 are provided. The heat medium circulation pump 14 is installed on the connecting pipe between the outlet of the second heat exchange channel of the heat storage tank and the inlet of the second heat exchange channel of the first stage preheater. The third switch valve 20 is installed on the connecting pipe between the heat medium circulation pump 14 and the inlet of the second heat exchange channel of the first stage preheater. The fourth switch valve 21 is installed on the connecting pipe between the heat medium circulation pump 14 and the inlet of the second heat exchange channel of the heat storage tank.

[0062] Preferably, the evaporator 2 is a shell-and-tube heat exchanger or a plate heat exchanger.

[0063] Preferably, the evaporator 2 in this embodiment is a shell-and-tube heat exchanger.

[0064] Preferably, the primary preheater 8 is a shell-and-tube heat exchanger or a plate heat exchanger; The secondary preheater 9 is a shell-and-tube heat exchanger or a plate heat exchanger. The tertiary preheater 10 is a shell-and-tube heat exchanger or a plate heat exchanger.

[0065] The preheater is used to preheat the feed of the evaporation and concentration system while recovering the waste heat of the discharged medium, thereby reducing system energy consumption and improving energy-saving effect. One-stage or multi-stage preheating is adopted. In this embodiment, the preheater is a three-stage preheater.

[0066] Preferably, the exhaust gas condenser 11 is a shell-and-tube heat exchanger or a plate heat exchanger.

[0067] The tail gas condenser 11 is preferably a shell-and-tube heat exchanger, which further cools the non-condensable gas after heat exchange and removes the entrained droplets and vapors.

[0068] Preferably, the radioactive waste evaporation and concentration system further includes: The feed pump 12 is installed on the feed pipe connected to the inlet of the first heat exchange channel of the first stage preheater. The feed pipe is used to introduce the radioactive waste liquid to be treated.

[0069] Feed pump 12, condensate pump 13, heat medium circulation pump 14, and concentrate pump 15 are used for fluid transport within the system, preferably centrifugal pumps.

[0070] The radioactive waste liquid evaporation and concentration system in this embodiment also includes supporting pipelines and valves.

[0071] Specifically, in this embodiment, the separator / purifier 1 is provided with a secondary steam outlet, a vapor-liquid mixture inlet, a circulating liquid outlet, a concentrate reflux port, and a tower top condensate reflux port; the evaporator is provided with a material inlet, a material outlet, a heat flow inlet, a condensate outlet, and a non-condensable gas outlet; the condensate tank 6 is provided with a condensate inlet, a condensate outlet, a non-condensable gas outlet, a balance pipe interface, and a condensate outlet; the primary preheater 8 is provided with a cold flow inlet, a cold flow outlet, a heat flow inlet, and a heat flow outlet; the secondary preheater 9 is provided with a cold flow inlet, a cold flow outlet, a heat flow inlet, and a heat flow outlet; the tertiary preheater 10 is provided with a cold flow inlet, a cold flow outlet, a heat flow inlet, a condensate outlet, and a non-condensable gas outlet; the heat storage tank 7 is provided with a concentrate inlet, a concentrate outlet, a heat transfer medium reflux port, a heat transfer medium outlet, and a water inlet; the steam compressor 3 is provided with a steam inlet, a steam outlet, and a liquid spray port; and the tail gas condenser 11 is provided with a medium to be cooled inlet and a cooled medium outlet.

[0072] The steam compressor 3's steam inlet is connected to the secondary steam outlet of the separator / purifier 1, and the steam outlet is connected to the evaporator's hot flow inlet. The separator / purifier 1's circulating liquid outlet is connected to the evaporator's material inlet via a lower circulating pipe 27, and the vapor-liquid mixture inlet is connected to the evaporator's material outlet via an upper circulating pipe 28. The concentrated liquid return port is connected to the concentrated liquid outlet of the heat storage tank 7. The evaporator's condensate outlet is connected to the condensate inlet of the condensate tank 6. The non-condensable gas outlet of the condensate tank 6 is connected to the hot flow inlet of the tertiary preheater 10, and the condensate inlet is connected to the condensate outlet of the tertiary preheater 10. The primary preheater 8's hot flow outlet is connected to the heat transfer medium return port of the heat storage tank 7, and the cold flow outlet is connected to the cold flow inlet of the secondary preheater 9. The secondary preheater 9's cold flow outlet is connected to the cold flow inlet of the tertiary preheater 10. The exhaust gas condenser 11's uncooled medium inlet is connected to the non-condensable gas outlet of the tertiary preheater 10, and the cooled medium outlet is connected to the external exhaust gas treatment system. The heat storage tank 7's water inlet is connected to the external deionized water interface.

[0073] The feed pump 12 is connected to the external waste liquid inlet pipeline of the system, and the feed pump 12 outlet is connected to the cold flow inlet of the primary preheater 8; the condensate pump 13 inlet is connected to the condensate outlet of the condensate tank 6, and the condensate pump 13 outlet is connected to the hot flow inlet of the secondary preheater 9; the heat medium circulation pump 14 inlet is connected to the heat medium outlet of the heat storage tank 7, and the heat medium circulation pump 14 outlet is connected to the hot flow inlet of the primary preheater 8; the concentrate pump 15 outlet is connected to the concentrate inlet of the heat storage tank 7; a branch pipeline is provided on the pipeline connecting the non-condensable gas outlet of the condensate tank 6 and the hot flow inlet of the tertiary preheater 10, which connects to the non-condensable gas outlet of the evaporator; a branch pipeline is provided on the pipeline connecting the outlet of the steam compressor 3 and the hot flow inlet of the evaporator, which connects to the balance pipe interface of the condensate tank 6.

[0074] The lower circulation pipe 27 is equipped with a first forced circulation pump 4, a discharge pipe connected to the inlet of the concentrate pump 15, and a feed pipe connected to the cold flow outlet of the tertiary preheater 10. The connection pipe between the concentrate return port of the separator purifier 1 and the concentrate outlet of the heat storage tank 7 is equipped with a first switch valve 18 and a branch. The branch is connected to the external concentrate interface of the system, and a second switch valve 19 is provided on the branch.

[0075] The outlet pipe of the condensate pump 13 is provided with branch pipes, which are respectively connected to the injection port of the steam compressor 3 and the condensate return port at the top of the separator purifier 1. The branch pipes are respectively equipped with a water spray regulating valve 16 and a return regulating valve 17. The outlet pipe of the heat medium circulation pump 14 is provided with a third switch valve 20, and is also provided with a branch pipe connected to the heat storage tank 7 heat medium return pipe.

[0076] The outlet branch pipeline of the hot medium circulation pump 14 is equipped with a fourth switching valve 21.

[0077] Specifically, the following design conditions are used as an example to illustrate the radioactive waste liquid evaporation and concentration system: Driven by the feed pump 12, the radioactive waste liquid is preheated through the cold flow side of the primary preheater 8, secondary preheater 9, and tertiary preheater 10, and then enters the system through the lower circulation pipe 27 (wherein, after the primary preheating, the raw material liquid temperature rises from 10~20℃ to 25~35℃, and the heat transfer medium temperature decreases from 70~80℃ to 20~30℃; after the secondary preheating, the raw material liquid temperature rises from 25~35℃ to 65~75℃, and the evaporation condensate temperature decreases from 105~115℃ to 35~45℃; after the tertiary preheating, the raw material liquid temperature rises from 65~75℃ to 75~85℃, and the non-condensable gas temperature decreases from 105~115℃ to 75~85℃). Radioactive waste liquid, driven by either the first forced circulation pump 4 or the second forced circulation pump 5, enters the cold flow side from the lower material inlet of the evaporator through the lower circulation pipe 27. After heat exchange with the heating steam on the hot flow side, it boils and evaporates into a vapor-liquid mixture, which then enters the separator purifier 1 through the upper circulation pipe 28. The separator purifier 1 adopts a multi-stage combined purification method of "gravity + cyclone + filtration". The vapor phase section is equipped with a cyclone plate, a sieve plate, and a packing demister from bottom to top. After the vapor-liquid mixture enters the separator purifier 1, it first undergoes preliminary vapor-liquid separation under the action of gravity. The separated liquid phase returns to the lower circulation pipe 27 to continue participating in the circulation evaporation. The vapor phase rises and passes through the cyclone plate to remove larger droplets before entering the sieve plate purification section. The sieve plate purification section uses evaporation condensate for steam washing. Through the countercurrent contact mass exchange between the evaporation condensate return liquid and the rising vapor phase, the secondary steam carries radionuclides and salts to the liquid phase. Subsequently, the vapor phase continues to rise and passes through the packing for further filtration and purification before being discharged from the secondary steam outlet of the separator purifier 1 and entering the inlet of the steam compressor 3. Low-pressure secondary steam (80~90℃, 47~90kPaA) is compressed to increase its temperature and pressure (105~115℃, 121~170kPaA) and then enters the shell side of the evaporator through the hot flow inlet to exchange heat with the material on the cold flow side. After heat exchange, the secondary steam condenses into liquid (105~115℃) and is discharged from the condensate outlet into the condensate tank. Driven by the condensate pump 13, most of the high-temperature condensate enters the hot flow side of the secondary preheater 9, preheats the feed, and is then discharged from the system (35~45℃). A small portion is used for saturated liquid injection in the steam compressor 3 and return washing in the separator purifier 1. During the waste liquid evaporation process, a small amount of non-condensable gas accumulates inside the system. This gas is collected uniformly through the evaporator shell side and the top of the condensate tank 6 and then connected to the hot flow inlet of the tertiary preheater 10. After preheating the feed, the condensate flows to the condensate tank 6, and the non-condensable gas enters the tail gas condenser 11. After further cooling, it is discharged into the tail gas treatment system.

[0078] The aforementioned forced circulation pump consists of two devices connected in parallel and serving as backups for each other. When the forced circulation pump malfunctions or requires maintenance, the devices can be quickly switched by adjusting the inlet and outlet valves of the pump body. A bypass for the circulation pump is also provided to retain the natural circulation operation mode (the sixth switch valve 23, the seventh switch valve 24, the eighth switch valve 25, and the ninth switch valve 26 are closed, and the fifth switch valve 22 is opened).

[0079] The evaporation process operates in a continuous feeding and intermittent concentrate discharge mode, but a continuous concentrate discharge mode is also possible. As evaporation proceeds, the material concentration within the system gradually increases. Once the preset concentration is reached, the system prepares to discharge. In the intermittent discharge mode, the first switch valve 18 and the fourth switch valve 21 are opened, the second switch valve 19 and the third switch valve 20 are closed, and the heat transfer medium circulation pump 14 and the concentrate pump 15 are started. Through indirect heat exchange between the concentrate and the heat transfer medium, the residual heat of the concentrate is stored in the heat storage tank 7, simultaneously achieving the effect of cooling the concentrate. After the heat storage process is completed, the heat transfer medium circulation pump 14 and the first switch valve 18, the third switch valve 20, and the fourth switch valve 21 are closed, and the second switch valve 19 is opened. The concentrate is then discharged from the system via the concentrate pump 15. When the system restarts, the heat transfer medium circulation pump 14 is turned on, the third switch valve 20 is turned on, and the fourth switch valve 21 is turned off. The heat transfer medium enters the hot flow side of the primary preheater 8 to preheat the feed. Alternatively, after the system is filled with liquid, the first switch valve 18 and the concentrate pump 15 are turned on, and the second switch valve 19, the third switch valve 20, and the fourth switch valve 21 are turned off. The system preheating is completed through indirect heat exchange between the liquid and the heat transfer medium in the heat storage tank 7. When the continuous discharge operation mode is adopted, the second switch valve 19 and the third switch valve 20 are turned on, the first switch valve 18 and the fourth switch valve 21 are turned off, and the heat transfer medium circulation pump 14 and the concentrate pump 15 are turned on. The waste heat of the concentrate is indirectly transferred through the heat transfer medium for feed preheating.

[0080] The radioactive waste liquid evaporation and concentration system in this embodiment achieves multi-stage waste heat recovery, effectively increasing the concentration and concentration ratio of the evaporated concentrate, and reducing system energy consumption. The system has a simple structure and reasonable design. By setting a forced circulation pump in the evaporation circulation pipeline to ensure the fluid flow rate in the heat exchange tube, it solves the problems of low concentration ratio, low output concentration, and small processing scale inherent in natural circulation systems. Even when the system starts up, the material concentration increases, or the heat exchange temperature difference decreases, it can still maintain a high circulation flow state, effectively increasing the evaporation output concentration and concentration ratio. Simultaneously, addressing the difficulty in recovering waste heat from the intermittent discharge operation mode of the radioactive waste liquid evaporation and concentration system, a heat storage tank 7 is installed. The waste heat from the concentrate is stored in the heat storage tank 7 using a heat transfer medium for preheating the feed before system startup, accelerating system startup and reducing system consumption. Furthermore, considering the system operation issues during forced circulation pump maintenance, this invention sets up two forced circulation pumps in parallel as backups for each other, ensuring continuous system operation in case of failure or maintenance. Through the above design, the concentration of the evaporation concentrate can be increased from the current conventional 330g / L to over 500g / L, reducing the system start-up preheating energy consumption by more than 20%, and achieving efficient and stable evaporation treatment of radioactive waste liquid.

[0081] The following explanation uses a radioactive waste evaporation and concentration system with a processing capacity of 3000 kg / h employing this process as an example. During the start-up phase, the system is filled with approximately 15 m³ of feed liquid. 3 Preheating from ambient temperature (considered at 20℃) to the target temperature (considered at 80℃) consumes approximately 1020kW of heat. By recovering the waste heat of the concentrate through a heat transfer medium and using it for preheating the materials during system startup, the initial temperature of the materials can be increased from 20℃ to approximately 36℃. Further heating to the target temperature (considered at 80℃) consumes approximately 750kW of heat, a reduction of 270kW, resulting in an energy saving of 26%.

[0082] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A radioactive waste liquid evaporation and concentration system, characterized in that, include: The primary preheater includes: a primary preheater body, a first heat exchange channel of the primary preheater disposed on the primary preheater body, and a second heat exchange channel of the primary preheater disposed on the primary preheater body, wherein radioactive waste liquid is introduced through the inlet of the first heat exchange channel of the primary preheater. The secondary preheater includes: a secondary preheater body, a first heat exchange channel of the secondary preheater disposed on the secondary preheater body, and a second heat exchange channel of the secondary preheater disposed on the secondary preheater body, wherein the inlet of the first heat exchange channel of the secondary preheater is connected to the outlet of the first heat exchange channel of the primary preheater. An evaporator includes: an evaporator body, a first heat exchange channel of the evaporator body disposed on the evaporator body, and a second heat exchange channel of the evaporator body disposed on the evaporator body, wherein the inlet of the first heat exchange channel of the evaporator body is connected to the outlet of the first heat exchange channel of the secondary preheater. The separator / purifier has its bottom inlet connected to the outlet of the first heat exchange channel of the evaporator, its top outlet connected to the inlet of the second heat exchange channel of the evaporator, and its outlet connected to the inlet of the second heat exchange channel of the secondary preheater. The evaporated condensate is discharged from the outlet of the second heat exchange channel of the secondary preheater. The bottom outlet of the separator / purifier is connected to the inlet of the first heat exchange channel of the evaporator.

2. The radioactive waste liquid evaporation and concentration system according to claim 1, characterized in that, The separator purifier includes: a separator purifier body, a cyclone plate, a sieve plate, and a packed demister arranged from bottom to top within the separator purifier body.

3. The radioactive waste liquid evaporation and concentration system according to claim 1, characterized in that, Also includes: The condensate tank includes: a condensate tank body, a first condensate tank inlet, a second condensate tank inlet, a first condensate tank gas outlet, and a condensate tank condensate outlet disposed on the condensate tank body. The first condensate tank inlet is connected to the outlet of the second heat exchange channel of the evaporator, and the condensate tank condensate outlet is connected to the inlet of the second heat exchange channel of the secondary preheater. The three-stage preheater includes: a three-stage preheater body, a first heat exchange channel of the three-stage preheater body, and a second heat exchange channel of the three-stage preheater body. The inlet of the first heat exchange channel of the three-stage preheater is connected to the outlet of the first heat exchange channel of the two-stage preheater. The outlet of the first heat exchange channel of the three-stage preheater is connected to the inlet of the first heat exchange channel of the evaporator. The first gas outlet of the condensate tank is connected to the inlet of the second heat exchange channel of the three-stage preheater. The exhaust gas is discharged through the second outlet of the second heat exchange channel of the three-stage preheater. The first outlet of the second heat exchange channel of the three-stage preheater is connected to the second inlet of the condensate tank. The non-condensable gas outlet of the second heat exchange pipe of the evaporator is connected to the connecting pipe between the first gas outlet of the condensate tank and the inlet of the second heat exchange channel of the three-stage preheater.

4. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, The condensate tank also includes an electric heater installed inside the condensate tank body. The electric heater is used to heat the condensate inside the condensate tank body to generate steam, which is used to supplement the heat during the system operation and start-up preheating stages.

5. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, Also includes: A condensate pump is installed on the connecting pipe between the condensate outlet of the condensate tank and the inlet of the second heat exchange channel of the secondary preheater.

6. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, The primary preheater is either a shell-and-tube heat exchanger or a plate heat exchanger. The secondary preheater is a shell-and-tube heat exchanger or a plate heat exchanger. The tertiary preheater is either a shell-and-tube heat exchanger or a plate heat exchanger.

7. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, Also includes: The exhaust gas condenser is connected to the second outlet of the second heat exchange channel of the three-stage preheater.

8. The radioactive waste liquid evaporation and concentration system according to claim 7, characterized in that, The exhaust gas condenser is either a shell-and-tube heat exchanger or a plate heat exchanger.

9. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, Also includes: The fifth switch valve is connected to the outlet of the first heat exchange channel of the tertiary preheater and the inlet of the first heat exchange channel of the evaporator, respectively. The sixth switch valve, the first forced circulation pump, and the seventh switch valve are connected in sequence. The seventh switch valve is connected to the outlet of the first heat exchange channel of the three-stage preheater, and the sixth switch valve is connected to the inlet of the first heat exchange channel of the evaporator. The eighth switch valve, the second forced circulation pump, and the ninth switch valve are connected in sequence. The ninth switch valve is connected to the outlet of the first heat exchange channel of the three-stage preheater, and the eighth switch valve is connected to the inlet of the first heat exchange channel of the evaporator.

10. The radioactive waste liquid evaporation and concentration system according to claim 9, characterized in that, The first forced circulation pump is an axial flow pump or a mixed flow pump; The second forced circulation pump is either an axial flow pump or a mixed flow pump.

11. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, The condensate tank also includes a second gas outlet for the condensate tank, which is connected to the inlet of the second heat exchange channel of the evaporator.

12. The radioactive waste liquid evaporation and concentration system according to claim 3, characterized in that, Also includes: The steam compressor is connected to the top outlet of the separator and purifier tower, and also to the inlet of the second heat exchange channel of the evaporator.

13. The radioactive waste liquid evaporation and concentration system according to claim 12, characterized in that, The steam compressor is also connected to the condensate outlet of the condensate tank.

14. The radioactive waste liquid evaporation and concentration system according to claim 12, characterized in that, The steam compressor can be any one of the following: Roots steam compressor, centrifugal steam compressor, or screw steam compressor.

15. The radioactive waste liquid evaporation and concentration system according to claim 12, characterized in that, Also includes: A water spray regulating valve is installed on the connecting pipe between the condensate outlet of the condensate tank and the steam compressor. A reflux regulating valve is installed on the connecting pipe between the condensate outlet of the condensate tank and the reflux inlet at the top of the separator / purifier tower.

16. The radioactive waste liquid evaporation and concentration system according to claim 1, characterized in that, Also includes: A heat storage tank includes: a heat storage tank body, a first heat exchange channel disposed on the heat storage tank body, and a second heat exchange channel disposed on the heat storage tank body. The outlet of the second heat exchange channel is connected to the inlet of the second heat exchange channel of the primary preheater, the outlet of the second heat exchange channel of the primary preheater is connected to the inlet of the second heat exchange channel of the heat storage tank, the outlet of the first heat exchange channel of the heat storage tank is connected to the inlet of the separator / purifier tower, and the inlet of the first heat exchange channel of the heat storage tank is connected to the outlet of the separator / purifier tower.

17. The radioactive waste liquid evaporation and concentration system according to claim 16, characterized in that, The outlet of the second heat exchange channel of the heat storage tank is connected to the inlet of the second heat exchange channel of the heat storage tank.

18. The radioactive waste liquid evaporation and concentration system according to claim 16, characterized in that, Also includes: The system includes a concentrate pump, a first switch valve, and a second switch valve. The concentrate pump is installed on the connecting pipe between the inlet of the first heat exchange channel of the heat storage tank and the outlet of the separator / purifier tower. The concentrate pump is used to pump the concentrate flowing out of the outlet of the separator / purifier tower into the first heat exchange channel of the heat storage tank. The first switch valve is installed on the connecting pipe between the outlet of the first heat exchange channel of the heat storage tank and the inlet of the separator / purifier tower. The inlet of the concentrate discharge pipe is connected to the connecting pipe between the first switch valve and the outlet of the first heat exchange channel of the heat storage tank. The second switch valve is installed on the concentrate discharge pipe, which is used to discharge the concentrate. The system includes a heat medium circulation pump, a third switch valve, and a fourth switch valve. The heat medium circulation pump is installed on the connecting pipe between the outlet of the second heat exchange channel of the heat storage tank and the inlet of the second heat exchange channel of the first-stage preheater. The third switch valve is installed on the connecting pipe between the heat medium circulation pump and the inlet of the second heat exchange channel of the first-stage preheater. The fourth switch valve is installed on the connecting pipe between the heat medium circulation pump and the inlet of the second heat exchange channel of the heat storage tank.

19. The radioactive waste liquid evaporation and concentration system according to claim 1, characterized in that, The evaporator can be a shell-and-tube heat exchanger or a plate heat exchanger.

20. The radioactive waste liquid evaporation and concentration system according to claim 1, characterized in that, Also includes: The feed pump is installed on the feed pipe connected to the inlet of the first heat exchange channel of the first stage preheater. The feed pipe is used to introduce the radioactive concentrate.

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