Rectification separation device and rectification separation method

Abstract

The present invention discloses a rectification separation device and a rectification separation method, and relates to the technical field of rectification separation, the rectification separation device comprises: a separation tower group, the separation tower group comprises a plurality of separation towers which are sequentially connected in series along a first direction, and the tower diameters of the plurality of separation towers are sequentially reduced in the first direction; the exhaust ports are formed in the tops of the separation towers, and the exhaust port of the previous separation tower is connected with the feeding port of the next separation tower through a conveying pipeline. According to the rectification separation device, the technical problems of large equipment size and high energy consumption caused by huge requirement on evaporation capacity in the separation towers of the existing rectification separation device are solved, and according to the optimal gas-liquid load curve in the separation towers, the maximum gas-liquid loads of the plurality of separation towers are gradually reduced, so that the energy consumption is reduced. And the gas-liquid load in each separation tower is fully close to the optimal gas-liquid load in the separation tower, so that the energy consumption of the whole set of device is effectively reduced while the required product is produced, and the equipment scale is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of distillation separation, and in particular to a distillation separation device and a distillation separation method. Background Art

[0002] Processes such as stable isotope enrichment and isomer separation have a very small total separation coefficient α (≦1.008), require a huge amount of evaporation in the tower, and often have more than 2,000 theoretical plates. These characteristics make stable isotope separation extremely difficult and require a huge cost. Deep cryogenic distillation precision separation technology is a method of separating mixed gases through a distillation process at extremely low temperatures. It is widely used in air separation, natural gas processing, chemical industry and other fields. This technology uses the difference in boiling points of different components to achieve efficient separation under deep cryogenic conditions. It is suitable for difficult-to-separate systems and can therefore be used in the field of stable isotope enrichment.

[0003] However, the existing distillation separation device requires a huge evaporation volume in the separation tower, resulting in a large equipment volume and high energy consumption. Therefore, a distillation separation device and a distillation separation method are proposed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a distillation separation device and a distillation separation method, which solve the technical problems of the existing distillation separation device that the equipment volume is large and the energy consumption is high due to the huge evaporation amount requirement in the separation tower.

[0005] To achieve the above object, the present invention provides a distillation separation device, comprising:

[0006] A separation tower group, the separation tower group comprising: a plurality of separation towers sequentially arranged in series along a first direction, wherein the tower diameters of the plurality of separation towers are sequentially reduced in the first direction, so that the maximum gas-liquid loads of the plurality of separation towers are gradually reduced;

[0007] An exhaust port is arranged at the top of the separation tower, the exhaust port of the previous separation tower is connected to the feed port of the next separation tower through a conveying pipeline, and the exhaust port on the last separation tower is connected to a storage device;

[0008] A liquid discharge port is provided at the bottom of the separation tower, and is used to discharge the waste liquid in the separation tower;

[0009] A heater is arranged at the bottom of the separation tower, and the heater is used to increase the amount of evaporation gas at the bottom of the tower;

[0010] An adsorption purification device is connected to the first separation tower, and is used for purifying the light isotope raw material to obtain raw gas and transporting the raw gas to the first separation tower.

[0011] Preferably, the adsorption purification device is connected to a heat exchanger, the hot end inlet of the heat exchanger is used to input light isotope gas, the hot end outlet of the heat exchanger is connected to the feed port of the adsorption purification device, and the drain port of the first separation tower is connected to the first cold end inlet of the heat exchanger, and the drain ports of the other separation towers except the first separation tower are all connected to a liquid storage tank, and the liquid storage tank is connected to the second cold end inlet of the heat exchanger.

[0012] Preferably, a condenser is provided at the top of each separation tower, and liquid nitrogen at normal pressure is filled into the condenser, and the liquid nitrogen level in the condenser is 1 / 3 of the designed liquid level.

[0013] Preferably, a stop valve is provided on the delivery pipeline between two adjacent separation towers, and the stop valve is used to control the on-off of the delivery pipeline.

[0014] Correspondingly, the technical solution of the present invention further provides a distillation separation method, which is applied to any of the distillation separation devices described above, and the distillation separation method comprises:

[0015] Controlling the light isotope raw material to enter the adsorption purification device for purification to obtain a raw gas, the raw gas enters the first separation tower and forms a liquid after condensation at the top of the first separation tower and accumulates at the bottom of the first separation tower;

[0016] After the liquid level at the bottom of the first separation tower reaches a set value, the heater at the bottom of the first separation tower is turned on to increase the amount of evaporation gas at the bottom of the tower to a maximum value, obtain product gas, and control the first separation tower to establish an abundance gradient;

[0017] After the abundance gradient of the previous separation tower is established, the delivery pipeline is slowly opened, and the heater in the previous separation tower is gradually closed under control, so that the product gas at the top of the previous separation tower enters the top of the next separation tower from the delivery pipeline, condenses, and forms liquid that accumulates at the bottom of the next separation tower;

[0018] After the liquid level at the bottom of the next separation tower reaches a set value, the heater at the bottom of the next separation tower is turned on to increase the amount of evaporated gas at the bottom of the tower to a maximum value to obtain product gas;

[0019] When each of the separation towers in the overall distillation separation device reaches distillation equilibrium, the product gas obtained at the top of the last separation tower is the required high-abundance light isotope gas.

[0020] Preferably, after the step of turning on the heater at the bottom of the next separation tower to increase the amount of evaporation gas at the bottom of the tower to a maximum value to obtain product gas, it also includes: controlling the full reflux operation at the beginning stage of each separation tower to make the mass transfer driving force in the previous separation tower reach the designed maximum value, so as to accelerate the distillation equilibrium speed of each separation tower.

[0021] Preferably, the steps to be achieved by each of the separation towers in the overall distillation separation device further include: the heater at the bottom of each separation tower is not turned on under normal operating conditions, and the liquid at the bottom of each separation tower is maintained at a certain liquid level.

[0022] Preferably, before the step of controlling the light isotope raw material to enter the adsorption purification device for purification to obtain the raw gas, it also includes: controlling the overall distillation separation device to be evacuated so that the vacuum degree in the overall distillation separation device is not less than the set vacuum degree, and after the vacuum degree in the overall distillation separation device is qualified, the detector electronic control is used to detect whether it is working normally, and after the electronic control detection is completed, the temperature inside each separation tower is controlled to be lowered until the temperature inside each separation tower is 10 to 15°C higher than the design temperature.

[0023] Preferably, the step of controlling and lowering the temperature inside each of the separation towers comprises: a condenser is provided at the top of each of the separation towers, liquid nitrogen at normal pressure is poured into the condenser, and the liquid nitrogen level in the condenser is 1 / 3 of the designed liquid level, and the temperature inside the separation tower is lowered by heat exchange.

[0024] Preferably, after the step of each separation tower in the overall rectification and separation device reaching a rectification equilibrium, the method further comprises:

[0025] When light isotope gases of different abundance levels need to be collected, the heater at the bottom of the corresponding separation tower is started to increase the mass transfer driving force in the corresponding separation tower, thereby increasing the gas-liquid load in the corresponding separation tower;

[0026] After more light isotope gas of corresponding abundance is obtained at the top of the corresponding separation tower, the excess light isotope gas in the corresponding separation tower is extracted, and the remaining light isotope gas enters the next separation tower to continue enriching the light isotope gas of corresponding abundance in the next separation tower.

[0027] Relative to the above background technology, a distillation separation device provided by the present invention has the following beneficial effects: by setting a plurality of separation towers with different maximum gas-liquid loads in series, according to the optimal gas-liquid load curve in the separation tower, a plurality of separation towers with different tower diameters are set, and the maximum gas-liquid load of the plurality of separation towers is gradually reduced, so that the gas-liquid load in each separation tower is sufficiently close to the optimal gas-liquid load in the separation tower during the actual separation of light isotope gas, thereby reducing the energy consumption of the entire device and reducing the equipment scale while producing the required product. On the other hand, by starting the heater at the bottom of the corresponding separation tower, the mass transfer driving force in the corresponding separation tower is increased to increase the gas-liquid load in the corresponding separation tower, so that the top of the corresponding separation tower obtains more light isotope gas of corresponding abundance, and the excess light isotope gas in the corresponding separation tower is extracted, and the light isotope gas in the corresponding separation tower can be collected according to demand, thereby continuously producing light isotope gas of different abundance levels, and the practicality is better. The distillation separation method used in the present invention also has the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 A schematic diagram of an optimal gas-liquid load curve in a separation tower provided in an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of an actual gas-liquid load curve in a separation tower provided in an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the working principle of the distillation separation device provided in an embodiment of the present invention.

[0032] Specifically, 1-separation tower; 2-heater; 3-adsorption purification device; 4-heat exchanger; 401-hot end inlet 401; 402-hot end outlet; 403-first cold end inlet; 404-second cold end inlet; 405-first cold end outlet; 406-second cold end outlet; 5-transport pipeline; 501-stop valve; 6-liquid storage tank. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. 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] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] like Figure 1 As shown, in order to achieve the above-mentioned purpose, the present invention provides a distillation separation device, including: a separation tower group 1 and an adsorption purification device 3.

[0036] Among them, the separation tower 1 group includes: a plurality of separation towers 1 arranged in series, and the tower diameters of the plurality of separation towers 1 are reduced in sequence, so that the maximum gas-liquid load of the plurality of separation towers 1 is reduced step by step, that is, the plurality of separation towers 1 are arranged in sections, so that in the actual separation process of the light isotope gas, the gas-liquid load in each separation tower 1 is sufficiently close to the optimal gas-liquid load in the separation tower 1, thereby reducing the energy consumption of the entire device and reducing the equipment scale while producing the required products; it should be noted that a plurality of separation towers 1 with the same sectioned tower diameter can be connected in parallel.

[0037] An exhaust port is provided at the top of the separation tower 1. In the same separation tower 1 group, the exhaust port of the previous separation tower 1 is connected to the feed port of the next separation tower 1 through the conveying pipeline 5 to ensure that the product gas at the top of the previous separation tower 1 enters the top of the next separation tower 1 from the conveying pipeline 5. In addition, the product gas obtained at the top of the last separation tower 1 is the required high-abundance light isotope gas. The storage device is connected through the exhaust port on the last separation tower 1 to convey the product gas obtained at the top of the last separation tower 1 to the storage device for storage.

[0038] A drain port is provided at the bottom of the separation tower 1, and the drain port is used to discharge the waste liquid in the separation tower 1. A drain valve is provided at the drain port, and the drain valve is used to control the on-off of the drain port. When there is a lot of waste liquid at the bottom of the separation tower 1 that needs to be cleaned, the drain valve is opened to safely discharge the waste liquid to ensure the normal operation of the overall distillation separation device.

[0039] A heater 2 is provided at the bottom of the separation tower 1, and the heater 2 is used to increase the amount of evaporation gas at the bottom of the tower to obtain product gas. Specifically, the heater 2 is an electric heater, and the amount of evaporation gas at the bottom of the tower is increased to a maximum value by the electric heater, so as to strengthen the mass transfer driving force of the separation tower 1 and obtain product gas.

[0040] Attach Figure 1Taking the orientation shown as an example, the separation tower 1 located on the far left is connected to the adsorption purification device 3, which is used to purify the light isotope raw material. Specifically, the impurities in the light isotope gas are selectively adsorbed by adsorption to obtain the raw gas, thereby achieving the purpose of preliminary purification, and the purified raw gas is transported to the first separation tower.

[0041] When in use, the light isotope raw material is controlled to enter the adsorption purification device 3 for purification to obtain the raw gas, the raw gas enters the first separation tower and condenses at the top of the first separation tower to form a liquid that accumulates at the bottom of the first separation tower; after the liquid level at the bottom of the first separation tower reaches the set value, the heater 2 at the bottom of the first separation tower is turned on to increase the amount of evaporation gas at the bottom of the tower to the maximum value, obtain product gas, and control the first separation tower to establish an abundance gradient; after the establishment of the abundance gradient of the previous separation tower 1 is completed, the conveying pipeline 5 is slowly opened, and the heater 2 in the previous separation tower 1 is controlled to be gradually closed, and the product gas at the top of the previous separation tower 1 enters the top of the next separation tower 1 from the conveying pipeline 5 to condense to form a liquid that accumulates at the bottom of the next separation tower 1; after the liquid level at the bottom of the next separation tower 1 reaches the set value, the heater 2 at the bottom of the next separation tower 1 is turned on to increase the amount of evaporation gas at the bottom of the tower to the maximum value, and obtain product gas; after each separation tower 1 in the overall distillation separation device reaches distillation equilibrium, the product gas obtained at the top of the last separation tower 1 is the required high-abundance light isotope gas. By setting separation towers 1 with different tower diameters, the gas-liquid load in the separation tower 1 during the deep low-temperature precision separation process is made sufficiently close to the ideal cascade, thereby reducing the gas-liquid load in the overall distillation separation device while satisfying the separation performance of the separation tower 1 in the corresponding segment, thereby achieving the purpose of reducing energy consumption.

[0042] In one embodiment of the present invention, the adsorption purification device 3 is connected to the heat exchanger 4, and the heat exchanger 4 is provided with a hot end inlet 401, a hot end outlet 402, a first cold end inlet 403, a second cold end inlet 404, a first cold end outlet 405, and a second cold end outlet 406. Specifically, the hot end inlet 401 of the heat exchanger 4 is used to input light isotope gas, the hot end outlet 402 of the heat exchanger 4 is connected to the feed port of the adsorption purification device 3, and the discharge port of the first separation tower is connected to the first cold end inlet 403 of the heat exchanger 4, and the discharge ports of the other separation towers 1 except the first separation tower are connected to the liquid storage tank 6, and the liquid storage tank 6 is connected to the second cold end inlet 404 of the heat exchanger 4. Specifically, the waste liquid at the bottom of the first separation tower is recycled from the first cold end inlet 403 and enters the heat exchanger 4, which plays a role in cooling the light isotope raw material, improving the cold utilization efficiency of the system while reducing the energy consumption of the device. The waste liquid at the bottom of the other separation towers 1 except the first separation tower is discharged through the drain port and then enters the liquid storage tank 6 for storage. After being discharged from the liquid storage tank 6, it is further recovered from the second cold end inlet 404 and enters the heat exchanger 4, which also plays the role of cooling the light isotope raw material, further improving the system's cold utilization efficiency while reducing the energy consumption of the device.

[0043] It should be noted that the waste liquid entering the first cold end inlet 403 is discharged from the first cold end outlet 405 after heat exchange with the light isotope raw material, and the waste liquid entering the second cold end inlet 404 is discharged from the second cold end outlet 406 after heat exchange with the light isotope raw material, and finally they are transported to the high-purity light isotope system for storage for subsequent use.

[0044] It should be noted that a condenser (not shown in the figure) is provided at the top of each separation tower 1, and liquid nitrogen at normal pressure is poured into the condenser to shorten the cooling time of the separation tower 1 through the condenser until the temperature inside the separation tower 1 is 10-15°C higher than the design temperature, and the supply of liquid nitrogen to the condenser is stopped. Preferably, the liquid nitrogen level in the condenser is 1 / 3 of the design level, which can ensure that the condenser always has enough liquid nitrogen for heat exchange, and at the same time ensure that the liquid nitrogen in the condenser is evenly distributed, thereby improving the heat exchange efficiency.

[0045] In one embodiment of the present invention, a stop valve 501 is provided on the delivery pipeline 5 between two adjacent separation towers 1. The stop valve 501 is used to control the on-off of the delivery pipeline 5, thereby accurately controlling the connection timing between the two adjacent separation towers 1 to ensure that the delivery pipeline 5 is slowly opened after the previous separation tower 1 completes the establishment of the abundance gradient, thereby maximizing the efficiency of each separation tower 1 in the overall distillation separation device in reaching distillation equilibrium.

[0046] The gas-liquid-solid three-phase integrated separation method adopted by the present invention specifically comprises the following steps: controlling the light isotope raw material to enter the adsorption purification device 3 for purification to obtain the raw gas, the raw gas enters the first separation tower and forms liquid after condensation at the top of the first separation tower and accumulates at the bottom of the first separation tower; after the liquid level at the bottom of the first separation tower reaches the set value, turning on the heater 2 at the bottom of the first separation tower to increase the evaporation gas volume at the bottom of the tower to the maximum value, obtaining the product gas, and controlling the first separation tower to establish an abundance gradient; after the previous separation tower 1 completes the establishment of the abundance gradient, slowly opening the conveying pipeline 5, and controlling the gradual closing of the heater 2 in the previous separation tower 1, and the upper The product gas at the top of a separation tower 1 enters the top of the next separation tower 1 from the conveying pipeline 5, condenses to form liquid and accumulates at the bottom of the next separation tower 1; after the liquid level at the bottom of the next separation tower 1 reaches the set value, the heater 2 at the bottom of the next separation tower 1 is turned on to increase the evaporation gas volume at the bottom of the tower to the maximum value to obtain product gas, and the full reflux operation at the beginning of each separation tower 1 is controlled to make the mass transfer driving force in the previous separation tower 1 reach the designed maximum value to accelerate the distillation equilibrium speed of each separation tower 1; after the separation towers 1 in the overall distillation separation device reach distillation equilibrium, the product gas obtained at the top of the last separation tower 1 is the required high-abundance light isotope gas.

[0047] It should be noted that the step of waiting for each separation tower 1 in the overall distillation separation device to reach distillation equilibrium also includes: the heater 2 at the bottom of each separation tower 1 is not turned on under normal operating conditions, and the liquid at the bottom of each separation tower 1 maintains a certain liquid level. At this time, the waste liquid in each separation tower 1 is safely discharged through the drain valve.

[0048] In one embodiment of the present invention, before controlling the light isotope raw material to enter the adsorption purification device 3 for purification to obtain the raw gas, it also includes: controlling the vacuum of the overall distillation separation device so that the vacuum degree in the overall distillation separation device is not less than the set vacuum degree. After the vacuum degree in the overall distillation separation device is qualified, the detector electronic control is normal. After the electronic control detection is completed, the temperature inside each separation tower 1 is controlled to be lowered until the temperature inside each separation tower 1 is higher than the design temperature by 10 to 15 ° C. Specifically, the condenser is filled with normal pressure liquid nitrogen, and the liquid nitrogen level in the condenser is 1 / 3 of the design level, and the temperature inside the separation tower 1 is lowered by heat exchange.

[0049] In one embodiment of the present invention, after the step of each separation tower 1 in the overall distillation separation device reaching distillation equilibrium, the method further includes:

[0050] When it is necessary to collect light isotope gases of different abundance levels, start the heater 2 at the bottom of the corresponding separation tower 1 to increase the mass transfer driving force in the corresponding separation tower 1, so as to increase the gas-liquid load in the corresponding separation tower 1; after the top of the corresponding separation tower 1 obtains more light isotope gases of corresponding abundance, the excess light isotope gases in the corresponding separation tower 1 are extracted, and the light isotope gases in the corresponding separation tower 1 can be collected according to demand, thereby continuously producing light isotope gases of different abundance levels, which is more practical. In addition, the remaining light isotope gases enter the next separation tower 1, and continue to enrich the light isotope gases of corresponding abundance in the next separation tower 1, and the required high-abundance light isotope gases will not be obtained at the top of the last separation tower 1.

[0051] Light isotopes For example, the specific implementation is as follows:

[0052] like Figure 2 As shown, the optimal gas-liquid load curve in the separation tower 1, n s is the theoretical plate number of the depletion stage, n e is the number of theoretical plates in the enrichment section. is the liquid load of the i-th mass transfer plate in the enrichment section, is the gas load of the jth mass transfer plate in the depletion section, For waste liquid discharge, is the required output.

[0053] It should be noted that when adjusting the optimal gas-liquid load in the separation tower 1, the feed point The required gas-liquid load is the largest at the feed point, and the required gas-liquid load gradually decreases from the feed point to the concentrate end and the waste liquid end, and the required gas-liquid load is zero at the concentrate end and the waste liquid end. Therefore, multiple separation towers 1 with different tower diameters are set to make the gas-liquid load in each separation tower 1 close to the optimal gas-liquid load in the separation tower 1, thereby making the overall distillation separation device more compact and improving the distillation efficiency of the overall distillation separation device.

[0054] like Figure 1 and Figure 2 As shown, according to the optimal gas-liquid load curve in the separation tower 1, the i-1 separation tower, the i-2 separation tower, the i-3 separation tower, the i-4 separation tower, the i-5 separation tower, ..., the im separation tower, and the in separation tower are arranged in sections to achieve different abundance levels. Continuous production of products. Among them, the exhaust port of the i-1 separation tower is connected to the feed port of the i-2 separation tower through the first feed pipeline, and the first stop valve 501 is arranged on the first feed pipeline, and the first stop valve 501 can control the on-off of the first feed pipeline; by analogy, the exhaust port of the i-2 separation tower is connected to the feed port of the i-3 separation tower through the second feed pipeline, and the second stop valve 501 is arranged on the second feed pipeline, and the second stop valve 501 can control the on-off of the second feed pipeline. The connection method between two adjacent separation towers 1 in the i-1 separation tower, the i-2 separation tower, the i-3 separation tower, the i-4 separation tower, the i-5 separation tower, ..., the im separation tower, and the in separation tower is the same, so it will not be repeated in detail.

[0055] like Figure 3 As shown, the i-1 separation tower, i-2 separation tower, i-3 separation tower, i-4 separation tower, i-5 separation tower, ..., im separation tower, in separation tower all adopt rectangular countercurrent symmetrical cascade towers, and the split ratio Z in each separation tower 1 is 0.5. Specifically, the curve represents the optimal quantitative value of the gas-liquid load in the tower, and the abundance change in the separation tower 1 is characterized by:

[0056] ,in:

[0057] k represents the coefficient, ε represents the concentration coefficient, i represents the number of mass transfer plates, and z represents the abundance distribution

[0058] The loads N1~N5, ..., Nm, Nn in each stage of the separation tower 1 and the optimal quantitative value of the gas-liquid load in the separation tower 1 must meet certain conditions to ensure that a positive abundance gradient is established inside the separation tower 1.

[0059] Before the overall distillation separation device is started, the overall distillation separation device is controlled to be evacuated so that the vacuum degree in the overall distillation separation device is not less than the set vacuum degree, which is set to 759.9 Torr. After the vacuum degree in the overall distillation separation device is qualified, the detector electronic control is tested to see if it is working normally. After the electronic control test is completed, the temperature inside each separation tower 1 is controlled to be lowered until the temperature inside each separation tower 1 is 10 to 15°C higher than the design temperature. Specifically, atmospheric pressure liquid nitrogen is poured into the condenser, and the liquid nitrogen level in the condenser is 1 / 3 of the design level. The temperature inside the separation tower 1 is lowered by heat exchange, shortening the cooling time of the overall distillation separation device.

[0060] raw material The gas is purified by the adsorption purification device 3 and then enters the i-1 separation tower. After the gas is condensed at the top of the i-1 separation tower, it accumulates at the bottom of the tower. When the liquid level at the bottom of the i-1 separation tower reaches the set value, the heater 2 at the bottom of the i-1 separation tower is turned on to slowly increase the evaporation gas volume at the bottom of the tower to the designed maximum value. The full reflux operation at the beginning of the i-1 separation tower is controlled so that the mass transfer driving force in the i-1 separation tower reaches the designed maximum value, thereby accelerating the distillation equilibrium speed of the i-1 separation tower.

[0061] After controlling the i-1 separation tower to establish the abundance gradient, slowly open the first stop valve 501, the product gas at the top of the i-1 separation tower enters the i-2 separation tower, and accumulates at the bottom of the tower after condensing at the top of the i-2 separation tower. After the liquid level at the bottom of the i-2 separation tower reaches the set value, turn on the heater 2 at the bottom of the i-2 separation tower to slowly increase the evaporation gas volume at the bottom of the tower to the designed maximum value. Similar to the i-1 separation tower, control the full reflux operation at the beginning of the i-2 separation tower so that the mass transfer driving force in the i-2 separation tower reaches the designed maximum value, so as to accelerate the distillation equilibrium speed of the i-2 separation tower.

[0062] After controlling the i-2 separation tower to establish the abundance gradient, slowly open the second stop valve 501. At the same time, the heater 2 at the bottom of the i-2 separation tower is gradually closed, and the product gas at the top of the i-2 separation tower enters the i-3 separation tower, and accumulates at the bottom of the tower after condensing at the top of the i-3 separation tower. After the liquid level at the bottom of the i-3 separation tower reaches the set value, turn on the heater 2 at the bottom of the i-3 separation tower, and slowly increase the evaporation gas volume at the bottom of the tower to the designed maximum value. Similar to the i-2 separation tower, control the full reflux operation at the beginning of the i-3 separation tower so that the mass transfer driving force in the i-3 separation tower reaches the designed maximum value, so as to accelerate the distillation equilibrium speed of the i-3 separation tower, and open the second stop valve 501.

[0063] The startup operations of the subsequent i-4 separation tower, i-5 separation tower, ..., im separation tower, and in separation tower are similar to the startup operations of the above-mentioned i-1 separation tower, i-1 separation tower, and i-3 separation tower, and will not be repeated here. The top of the last separation tower 1i-n is the required high abundance .

[0064] It should be noted that the distribution of abundance and separation level in one of the separation towers 1 satisfies The relationship between abundance, i is the separation level, ε is the concentration coefficient; k is the relative flow rate, which is related to the ratio of the optimal gas-liquid load in the tower and the actual gas-liquid load in the separation tower 1. The value of k must be positive to ensure that the gas-liquid load in the separation tower 1 As the abundance increases along the separation stage, along the movement path of the raw gas, the gas-liquid load in each separation tower 1 is controlled to decrease step by step, that is, there is a contraction flow between the previous separation tower 1 and the next separation tower 1, and the minimum gas-liquid load L of each separation tower 1 is limited, and the gas-liquid load ratio between the previous and next separation towers 1 can meet The k requirement for efficient enrichment.

[0065] It should be further explained that for the production of different abundance levels , then it is necessary to increase the gas-liquid load in the i-1 separation tower to the i-5 separation tower, ..., the im separation tower, and the in separation tower accordingly. Specifically, when it is necessary to take the low abundance at the top of the i-1 separation tower , then start the heater 2 at the bottom of the separation tower 1, and gradually increase the gas-liquid load in the i-1 separation tower. As the gas-liquid load in the i-1 separation tower increases, the mass transfer driving force in the i-1 separation tower increases accordingly. The mass transfer driving force inside the i-1 separation tower increases, and more low-abundance products can be obtained at the top of the tower. Product J, remove excess As a product, the rest Enter the next separation tower 1 and continue enrichment .

[0066] Similar to the operation of the i-1 separation tower, by adjusting the evaporation power of the heater 2 at the bottom of the subsequent separation tower 1, the gas-liquid load in the separation tower 1 is increased, thereby strengthening the mass transfer driving force without affecting the high abundance at the top of the in separation tower. Under the premise of production, other abundance levels are produced .

[0067] It should be noted that the accumulated liquid at the bottom of the i-1 separation tower to the i-5 separation tower, ..., the im separation tower, and the in separation tower is used to produce different abundance levels. Preparation: When the liquid level at the bottom of a separation tower 1 is lower than the warning value, the evaporation power of the electric heater at the bottom of the tower needs to be reduced, and the abundance The extraction volume is set until the liquid level at the bottom of the separation tower returns to the set level to ensure the normal production of high abundance at the top of the stage in separation tower. .

[0068] In summary, according to the optimal gas-liquid load curve in the separation tower 1, several separation towers 1 with different tower diameters are set, and the maximum gas-liquid loads of the several separation towers 1 are gradually reduced, so that in the actual separation process of the light isotope gas, the gas-liquid load in each separation tower 1 is sufficiently close to the optimal gas-liquid load in the separation tower 1, thereby effectively reducing the energy consumption of the entire device and reducing the equipment scale while producing the required products.

[0069] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0070] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A distillation separation device, characterized in that: include: A separation tower group, the separation tower group comprising: a plurality of separation towers sequentially arranged in series along a first direction, wherein the tower diameters of the plurality of separation towers are sequentially reduced in the first direction, so that the maximum gas-liquid loads of the plurality of separation towers are gradually reduced; An exhaust port is arranged at the top of the separation tower, the exhaust port of the previous separation tower is connected to the feed port of the next separation tower through a conveying pipeline, and the exhaust port on the last separation tower is connected to a storage device; A liquid discharge port is provided at the bottom of the separation tower, and is used to discharge the waste liquid in the separation tower; A heater is arranged at the bottom of the separation tower, and the heater is used to increase the amount of evaporation gas at the bottom of the tower; An adsorption purification device is connected to the first separation tower, and is used for purifying the light isotope raw material to obtain raw gas and transporting the raw gas to the first separation tower.

2. A distillation separation device according to claim 1, characterized in that: The adsorption purification device is connected to a heat exchanger, the hot end inlet of the heat exchanger is used to input light isotope gas, the hot end outlet of the heat exchanger is connected to the feed port of the adsorption purification device, and the drainage port of the first separation tower is connected to the first cold end inlet of the heat exchanger, and the drainage ports of the other separation towers except the first separation tower are all connected to a liquid storage tank, and the liquid storage tank is connected to the second cold end inlet of the heat exchanger.

3. A distillation separation device according to claim 1, characterized in that: A condenser is arranged at the top of each separation tower, and liquid nitrogen at normal pressure is filled into the condenser, and the liquid nitrogen level in the condenser is 1 / 3 of the designed liquid level.

4. A distillation separation device according to claim 1, characterized in that: A stop valve is arranged on the delivery pipeline between two adjacent separation towers, and the stop valve is used to control the on-off of the delivery pipeline.

5. A distillation separation method, applied to the distillation separation device according to any one of claims 1 to 4, characterized in that: The distillation separation method comprises: Controlling the light isotope raw material to enter the adsorption purification device for purification to obtain a raw gas, the raw gas enters the first separation tower and forms a liquid after condensation at the top of the first separation tower and accumulates at the bottom of the first separation tower; After the liquid level at the bottom of the first separation tower reaches a set value, the heater at the bottom of the first separation tower is turned on to increase the amount of evaporation gas at the bottom of the tower to a maximum value, obtain product gas, and control the first separation tower to establish an abundance gradient; After the abundance gradient of the previous separation tower is established, the delivery pipeline is slowly opened, and the heater in the previous separation tower is gradually closed under control, so that the product gas at the top of the previous separation tower enters the top of the next separation tower from the delivery pipeline, condenses, and forms liquid that accumulates at the bottom of the next separation tower; After the liquid level at the bottom of the next separation tower reaches a set value, the heater at the bottom of the next separation tower is turned on to increase the amount of evaporated gas at the bottom of the tower to a maximum value to obtain product gas; When each of the separation towers in the overall distillation separation device reaches distillation equilibrium, the product gas obtained at the top of the last separation tower is the required high-abundance light isotope gas.

6. A distillation separation method according to claim 5, characterized in that: After the step of turning on the heater at the bottom of the next separation tower to increase the amount of evaporation gas at the bottom of the tower to a maximum value to obtain product gas, the method further includes: controlling the full reflux operation at the beginning of each separation tower to make the mass transfer driving force in the previous separation tower reach the designed maximum value to accelerate the distillation equilibrium speed of each separation tower.

7. A distillation separation method according to claim 5, characterized in that: The steps to be achieved by each of the separation towers in the overall distillation separation device also include: the heater at the bottom of each separation tower is not turned on under normal operating conditions, and the liquid at the bottom of each separation tower is maintained at a certain liquid level.

8. A distillation separation method according to claim 5, characterized in that: Before the step of controlling the light isotope raw material to enter the adsorption purification device for purification to obtain the raw gas, it also includes: controlling the overall distillation separation device to be evacuated so that the vacuum degree in the overall distillation separation device is not less than the set vacuum degree. After the vacuum degree in the overall distillation separation device is qualified, the detector electronic control is used to determine whether it is working normally. After the electronic control detection is completed, the temperature inside each separation tower is controlled to be lowered until the temperature inside each separation tower is 10 to 15°C higher than the design temperature.

9. A distillation separation method according to claim 8, characterized in that: The step of controlling and lowering the temperature inside each of the separation towers comprises: a condenser is arranged at the top of each of the separation towers, normal pressure liquid nitrogen is poured into the condenser, and the liquid nitrogen level in the condenser is 1 / 3 of the designed liquid level, and the temperature inside the separation tower is lowered by heat exchange.

10. A distillation separation method according to claim 5, characterized in that: After the step of waiting for each separation tower in the overall rectification and separation device to reach rectification equilibrium, the method further includes: When light isotope gases of different abundance levels need to be collected, the heater at the bottom of the corresponding separation tower is started to increase the mass transfer driving force in the corresponding separation tower, thereby increasing the gas-liquid load in the corresponding separation tower; After more light isotope gas of corresponding abundance is obtained at the top of the corresponding separation tower, the excess light isotope gas in the corresponding separation tower is extracted, and the remaining light isotope gas enters the next separation tower to continue enriching the light isotope gas of corresponding abundance in the next separation tower.

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