A dual stable isotope co-production device and use method

Abstract

The present invention provides a dual stable isotope co-production device and a method of using the same. 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source. 18 The O2 enrichment submodule uses atmospheric pressure and low temperature distillation to continuously accumulate the rich O2 at the bottom of the distillation tower. 18 O liquid oxygen, achieved by connecting the front and rear stages in series 18 O liquid oxygen enrichment; 18 The cold nitrogen in the O2 distillation and enrichment module enters after being reheated (reheated to 110K) 13 CF4 distillation enrichment submodule, as 13 CF4 distillation enriches the cold source and cools the CF4 gas at the top of the distillation tower. 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source, to achieve 13 C and 18 Efficient co-production of O stable isotopes increases output 18 O and 13 The abundance of C stable isotopes.

Description

Technical Field

[0001] The present invention relates to a dual stable isotope co-production device and a use method thereof, belonging to the technical field of isotope co-production. Background Art

[0002] Industrial enrichment of stable isotopes is still one of the difficulties in cryogenic distillation technology. 18 O and 13 C stable isotopes account for an important proportion. High abundance 18 O stable isotopes have important applications in civil fields such as medicine, scientific research, and agriculture; 13 As a highly efficient source for detecting Helicobacter pylori, C stable isotopes have a huge market demand. 18 The supply of O stable isotopes is mostly monopolized by developed countries and regions such as the United States, Japan, and Europe. 13 The domestic market for C stable isotopes is completely monopolized by American suppliers. Therefore, the development of industrial-scale stable isotope cryogenic separation technology is of great significance at the national strategic level. 18 O and 13 C stable isotope co-production technology and equipment, simultaneously producing high abundance 18 O and 13 C stable isotope. Summary of the Invention

[0003] The present invention develops a dual stable isotope co-production device and its use method, 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source, to achieve 13 C and 18 Efficient co-production of O stable isotopes.

[0004] To achieve the purpose of the present invention, a dual stable isotope co-production device is provided, which consists of an 18O enrichment submodule and a 13C enrichment submodule. The raw gas of the 18O enrichment submodule comes from air separation oxygen, which is purified by an oxygen purification device. The volume purity of the raw oxygen reaches 5n. The outlet of the oxygen purification device is connected to the inlet of the intermediate evaporator of the Ⅰ-1 distillation tower. The upper and lower intermediate evaporators of the Ⅰ-1 distillation tower are respectively connected to the bottom of the upper tower section of the Ⅰ-1 distillation tower and the top of the lower tower section of the Ⅰ-1 distillation tower. The top of the upper tower section of the Ⅰ-1 distillation tower is connected to the condenser of the Ⅰ-1 distillation tower. The bottom of the lower tower section of the Ⅰ-1 distillation tower is commonly connected to the inlet of the Ⅰ-1 discharge stop valve A and the inlet of the Ⅰ-1 discharge stop valve F. -1 discharge stop valve A outlet is connected to the inlet of the intermediate evaporator of the distillation tower I-2, the intermediate evaporator of the distillation tower I-2 is respectively connected to the bottom of the upper tower section of the distillation tower I-2 and the top of the lower tower section of the distillation tower I-2, the top of the upper tower section of the distillation tower I-2 is connected to the condenser of the distillation tower I-2, the bottom of the lower tower section of the distillation tower I-2 is commonly connected to the inlet of the discharge stop valve B of the distillation tower I-2, the inlet of the drain stop valve G of the distillation tower I-2, and the outlet of the drain stop valve F of the distillation tower I-1, the outlet of the discharge stop valve B of the distillation tower I-2 is connected to the inlet of the intermediate evaporator of the next-level distillation tower, the outlet of the drain stop valve G of the distillation tower I-2 is connected to the bottom of the distillation tower I-2, the inlet of the discharge valve at the bottom of the distillation tower I-2, and the inlet of the drain valve at the bottom of the distillation tower I-1

[0005] As a preference: the Ⅰ-2 liquid outlet stop valve B is connected to the inlet of the intermediate evaporator of the next-stage distillation tower, the intermediate evaporator of the Ⅰ-n distillation tower is connected to the bottom of the upper tower section of the Ⅰ-n distillation tower and the top of the lower tower section of the Ⅰ-n distillation tower respectively, the top of the upper tower section of the Ⅰ-n distillation tower is connected to the bottom of the Ⅰ-n distillation tower condenser, the bottom of the lower tower section of the Ⅰ-n distillation tower is commonly connected to the inlet of the Ⅰ-n discharge stop valve, the inlet of the Ⅰ-n drainage stop valve, and the outlet of the drainage stop valve at the bottom of the previous-stage distillation tower, the outlet of the Ⅰ-n discharge stop valve is connected to the inlet of the intermediate evaporator of the Ⅱ-1 distillation tower, the intermediate evaporator of the Ⅱ-1 distillation tower is connected to the bottom of the upper tower section of the Ⅱ-1 distillation tower and the top of the lower tower section of the Ⅱ-1 distillation tower respectively, the bottom of the lower tower section of the Ⅱ-1 distillation tower is commonly connected to the inlet of the Ⅱ-1 discharge stop valve D, the inlet of the Ⅱ-1 drainage stop valve, and the outlet of the drainage stop valve at the bottom of the Ⅰ-n distillation tower The top of the upper tower section of the Ⅱ-1 distillation tower is connected to the bottom of the condenser of the Ⅱ-1 distillation tower, the outlet of the Ⅱ-1 discharge stop valve D is connected to the inlet of the intermediate evaporator of the Ⅱ-2 distillation tower, the upper and lower intermediate evaporators of the Ⅱ-2 distillation tower are respectively connected to the bottom of the upper tower section of the Ⅱ-2 distillation tower and the top of the lower tower section of the Ⅱ-2 distillation tower, the bottom of the lower tower section of the Ⅱ-2 distillation tower is commonly connected to the inlet of the Ⅱ-2 discharge stop valve, the inlet of the Ⅱ-2 drain stop valve, and the outlet of the drain stop valve at the bottom of the Ⅱ-1 distillation tower, the outlet of the Ⅱ-2 drain stop valve is safely emptied, the top of the upper tower section of the Ⅱ-2 distillation tower is connected to the bottom of the condenser of the Ⅱ-2 distillation tower, the outlet of the Ⅱ-2 discharge stop valve is connected to the inlet of the intermediate evaporator of the next-level distillation tower, the feed inlet of the product concentrating tower is connected to the outlet of the discharge stop valve of the previous-level distillation tower, the outlet of the product concentrating tower is connected to the feed inlet of the middle of the product purification tower, and the upper discharge port of the product purification tower is connected to the outlet of the upper discharge port of the product purification tower. 18 The O2 product, the top of the product concentration tower, and the top of the product purification tower are commonly connected to the bottom of the II-m distillation tower condenser. Preferably, the exhaust port of the I-1 distillation tower condenser, the exhaust port of the I-2 distillation tower condenser, the exhaust port of the I-n distillation tower condenser, the exhaust port of the II-1 distillation tower condenser, the exhaust port of the II-2 distillation tower condenser, the exhaust port of the II-m distillation tower condenser, and the exhaust ports of other omitted distillation tower condensers are commonly connected to the inlet of the waste gas storage tank, the outlet of the waste gas storage tank is connected to the inlet of the check valve, the outlet of the check valve is connected to the inlet of the boosting valve, and the outlet of the boosting valve is connected to the outlet of the air separation raw oxygen. The bottom of the lower tower section of the I-1 distillation tower, the bottom of the lower tower section of the I-2 distillation tower, the bottom of the lower tower section of the I-n distillation tower, the bottom of the lower tower section of the II-1 distillation tower, the bottom of the lower tower section of the II-2 distillation tower, the bottom of the product concentration tower, the bottom of the product purification tower, and the bottom of other omitted distillation towers are all equipped with oxygen electric heaters.

[0006] Preferably, the cold nitrogen outlet of the condenser of the Ⅰ-1 distillation tower, the cold nitrogen outlet of the condenser of the Ⅰ-2 distillation tower, the cold nitrogen outlet of the condenser of the Ⅰ-n distillation tower, the cold nitrogen outlet of the condenser of the Ⅱ-1 distillation tower, the cold nitrogen outlet of the condenser of the Ⅱ-2 distillation tower, the cold nitrogen outlet of the condenser of the Ⅱ-m distillation tower, and the cold nitrogen outlet of the condenser of the other omitted distillation towers are connected to the inlet of the nitrogen stop valve, and the outlet of the nitrogen stop valve is connected to the inlet of the rewarming heat exchanger. The nitrogen at the outlet of the rewarming heat exchanger is divided into two streams: ① as a heat source, purging and vaporizing 13 CF4 enrichment distillation tower bottom liquid, vaporization 13 CF4 is used as the raw material for the next stage of distillation; ② directly enters 13 CF4 enrichment distillation condenser, as a cold source, needs to pay attention to the following: ① Nitrogen vaporization 13 CF4 then merges with ②; the liquid nitrogen inlet of the condenser of Ⅰ-1 distillation tower, the liquid nitrogen inlet of the condenser of Ⅰ-2 distillation tower, the liquid nitrogen inlet of the condenser of Ⅰ-n distillation tower, the liquid nitrogen inlet of the condenser of Ⅱ-1 distillation tower, the liquid nitrogen inlet of the condenser of Ⅱ-2 distillation tower, the liquid nitrogen inlet of the condenser of Ⅱ-m distillation tower, and the liquid nitrogen inlets of other omitted distillation tower condensers are connected to the outlet of the liquid nitrogen pump, the inlet of the liquid nitrogen pump is connected to the outlet of the liquid nitrogen tank, the inlet of the liquid nitrogen tank is connected to the outlet of the liquid nitrogen stop valve, and the inlet of the liquid nitrogen stop valve is connected to the air separation liquid nitrogen.

[0007] As a preference: 13 The raw material of the C enrichment submodule comes from high-purity CF4 cylinder gas, which enters the adsorption purification device after 13 CF4 distillation submodule, the outlet of the adsorption purification device is connected to the inlet of the CF4 feed stop valve, the outlet of the CF4 feed stop valve is connected to the feed port of the i-1 distillation tower, the top of the i-1 distillation tower is connected to the bottom of the i-1 distillation tower condenser, the bottom of the i-1 distillation tower is connected to the inlet of the i-1 discharge stop valve, the outlet of the i-1 discharge stop valve is connected to the feed port of the i-2 distillation tower, the top of the i-2 distillation tower is connected to the bottom of the i-2 distillation tower condenser, the bottom of the i-2 distillation tower is connected to the inlet of the i-2 discharge stop valve, and the outlet of the i-2 discharge stop valve is connected to the next level 13 CF4 distillation tower feed port, is distillation tower feed port connected to the previous level 13 The outlet of the CF4 distillation tower discharge stop valve, the top of the is distillation tower is connected to the bottom of the is distillation tower condenser, the bottom of the is distillation tower is connected to the inlet of the is discharge stop valve, and the outlet of the is discharge stop valve is connected to the feed inlet of the ⅱ-1 distillation tower.

[0008] As a preference, the top of the ⅱ-1 distillation tower is connected to the bottom of the ⅱ-1 distillation tower condenser, the bottom of the ⅱ-1 distillation tower is connected to the inlet of the ⅱ-1 discharge stop valve, the outlet of the ⅱ-1 discharge stop valve is connected to the feed inlet of the ⅱ-2 distillation tower, the top of the ⅱ-2 distillation tower is connected to the bottom of the ⅱ-2 distillation tower condenser, the bottom of the ⅱ-2 distillation tower is connected to the inlet of the ⅱ-2 discharge stop valve, and the outlet of the ⅱ-2 discharge stop valve is connected to the next level13 The feed port of CF4 distillation tower and the feed port of II-t concentration tower are connected to the previous stage 13 CF4 distillation tower discharge stop valve outlet, ⅱ-t concentration tower top connected to ⅱ-t distillation tower condenser bottom, ⅱ-t distillation tower bottom outlet 13 Product C.

[0009] Preferably, the nitrogen inlet of the i-1 rectifying tower condenser, the nitrogen inlet of the i-2 rectifying tower condenser, the nitrogen inlet of the is rectifying tower condenser, the nitrogen inlet of the ⅱ-1 rectifying tower condenser, the nitrogen inlet of the ⅱ-2 rectifying tower condenser, and the nitrogen inlet of the ⅱ-t rectifying tower condenser are connected to the outlet of the rewarming heat exchanger, the nitrogen outlet of the i-1 rectifying tower condenser, the nitrogen outlet of the i-2 rectifying tower condenser, the nitrogen outlet of the is rectifying tower condenser, the nitrogen outlet of the ⅱ-1 rectifying tower condenser, the nitrogen outlet of the ⅱ-2 rectifying tower condenser, the nitrogen outlet of the ⅱ-t rectifying tower condenser, and other omitted rectifying towers The nitrogen outlet of the condenser is commonly connected to the inlet of the nitrogen reflux valve, and the outlet of the nitrogen reflux valve is connected to the air separation nitrogen inlet. The exhaust port of the i-1 distillation tower condenser, the exhaust port of the i-2 distillation tower condenser, the exhaust port of the is distillation tower condenser, the exhaust port of the ⅱ-1 distillation tower condenser, the exhaust port of the ⅱ-2 distillation tower condenser, the exhaust port of the ⅱ-2 distillation tower condenser, and the exhaust port of other omitted distillation tower condensers are commonly connected to the CF4 storage tank. CF4 electric heaters are all provided at the bottom of the i-1 distillation tower, the i-2 distillation tower, the is distillation tower, the ⅱ-1 distillation tower, the ⅱ-2 distillation tower, and the ⅱ-t distillation tower.

[0010] A method for using a dual stable isotope co-production device comprises the following steps:

[0011] 1) Before starting the system, it is necessary to evacuate the system, open the discharge stop valve A to the discharge stop valve E, the boost valve, the discharge stop valve K to the discharge stop valve P, and the nitrogen stop valve, and close the drain stop valve F to the drain stop valve J. The system material pipeline is evacuated to less than 10pa, and all valves are closed. Before starting the system, the entire device must be pre-cooled first. Slowly open the liquid nitrogen stop valve P, and the air separation atmospheric pressure liquid nitrogen enters the liquid nitrogen tank. After the liquid level in the liquid nitrogen tank reaches the specified value, start the liquid nitrogen pump, and simultaneously feed the liquid into the condenser of the Ⅰ-1 distillation tower, the condenser of the Ⅰ-2 distillation tower, the condenser of the Ⅰ-n distillation tower, the condenser of the Ⅱ-1 distillation tower, the condenser of the Ⅱ-2 distillation tower, and the condenser of the Ⅱ-m distillation tower. Nitrogen, the device starts to cool down. When the temperature value displayed by the system temperature measuring point drops to the set value, the raw oxygen of the air separation enters the intermediate evaporator of the Ⅰ-1 distillation tower after being purified by the oxygen purification device, and is condensed by the condenser of the Ⅰ-1 distillation tower and accumulates at the bottom of the lower tower section of the Ⅰ-1 distillation tower. When the accumulated liquid in the lower tower section of the Ⅰ-1 distillation tower submerges the entire lower tower section of the Ⅰ-1 distillation tower, turn on the oxygen electric heater and slowly increase the evaporation power to the rated value. After 2.5 months of distillation, a concentration gradient is established between the upper tower section of the Ⅰ-1 distillation tower and the lower tower section of the Ⅰ-1 distillation tower. At this time, the booster valve is slowly opened, and the exhaust gas at the top of the upper tower section of the Ⅰ-1 distillation tower passes through the exhaust gas storage tank, the check valve, and the booster valve and returns to the air separation device;

[0012] 2) Open the discharge stop valve A of I-1, and the product at the bottom of the lower section of the I-1 distillation tower is discharged from the cold box for reheating and vaporization, and then enters the intermediate evaporator of the I-2 distillation tower. The condenser of the I-2 distillation tower liquefies the oxygen in the tower and accumulates at the bottom of the lower section of the I-2 distillation tower. When the accumulated liquid in the lower section of the I-2 distillation tower submerges the entire lower section of the I-2 distillation tower, turn on the oxygen electric heater and slowly increase the evaporation power to the rated value. After 1.5 months of distillation, a concentration gradient is established between the upper section of the I-2 distillation tower and the lower section of the I-2 distillation tower. The exhaust gas at the top of the upper section of the I-2 distillation tower is returned to the air separation unit through the exhaust gas storage tank, the check valve, and the booster valve;

[0013] 3) Open the I-2 discharge stop valve B, and the bottom product of the lower tower section of the I-2 distillation tower is discharged from the cold box for reheating and vaporization, and then enters the next level distillation tower. It is worth noting that in the device of the present invention, 18 The O enrichment submodule is divided into a structured packing system and a random packing system. The structured packing system is cascaded to Ⅰ-1, Ⅰ-2, ..., Ⅰ-n, with a total of n stages; the random packing system is cascaded to Ⅱ-1, Ⅱ-2, ..., Ⅱ-m, with a total of m stages. The operation process of each cascade tower of the structured packing system is the same as that of the Ⅰ-1 distillation tower and the Ⅰ-2 distillation tower.

[0014] 4) The feed to the intermediate evaporator of the I-n distillation tower comes from the outlet of the liquid outlet stop valve at the bottom of the lower tower section of the previous distillation tower. The condenser of the I-n distillation tower liquefies the oxygen in the tower and accumulates at the bottom of the lower tower section of the I-n distillation tower. When the accumulated liquid in the lower tower section of the I-n distillation tower submerges the entire lower tower section of the I-n distillation tower, the oxygen electric heater is turned on and the evaporation power is slowly increased to the rated value. After one month of distillation, a concentration gradient is established between the upper tower section of the I-n distillation tower and the lower tower section of the I-n distillation tower. The exhaust gas at the top of the upper tower section of the I-n distillation tower is returned to the air separation unit through the exhaust gas storage tank, the check valve, and the booster valve;

[0015] 5) Open the I-n discharge stop valve C, and the bottom product of the lower tower section of the I-n distillation tower will be discharged from the cold box for reheating and vaporization, and then enter the random packing system (II-1, II-2, ..., II-m);

[0016] 6) First, the product at the bottom of the lower section of the II-n distillation tower is reheated and vaporized after exiting the cold box, and enters the intermediate evaporator of the II-1 distillation tower. The oxygen in the tower is liquefied by the condenser of the II-1 distillation tower and accumulates at the bottom of the lower section of the II-1 distillation tower. When the accumulated liquid in the lower section of the II-1 distillation tower submerges the entire lower section of the II-1 distillation tower, the oxygen electric heater is turned on, and the evaporation power is slowly increased to the rated value. After 0.8 months of distillation, a concentration gradient is established between the upper section of the II-1 distillation tower and the lower section of the II-1 distillation tower. The exhaust gas at the top of the upper section of the II-1 distillation tower is returned to the air separation unit through the exhaust gas storage tank, the check valve, and the booster valve;

[0017] 7) Open the II-1 discharge stop valve D, and the product at the bottom of the lower section of the II-1 distillation tower is discharged from the cold box for reheating and vaporization, and enters the intermediate evaporator of the II-2 distillation tower. The condenser of the II-2 distillation tower liquefies the oxygen in the tower and accumulates at the bottom of the lower section of the II-2 distillation tower. When the accumulated liquid in the lower section of the II-2 distillation tower submerges the entire lower section of the II-2 distillation tower, turn on the oxygen electric heater and slowly increase the evaporation power to the rated value. After 0.6 months of distillation, a concentration gradient is established between the upper section of the II-2 distillation tower and the lower section of the II-2 distillation tower. The exhaust gas at the top of the upper section of the II-2 distillation tower is returned to the air separation unit through the exhaust gas storage tank, the check valve, and the booster valve;

[0018] 8) Open the II-2 discharge stop valve E, and the bottom product of the lower section of the II-2 distillation tower is discharged from the cold box for reheating and vaporization, and then sent to the next distillation tower. It is worth noting that in the apparatus of the present invention, the random packing system is cascaded to II-1, II-2, ..., I-m, with a total of m stages. The operation process of each stage of the random packing system cascade tower is the same as that of the II-1 distillation tower and the II-2 distillation tower;

[0019] 9) The raw material of the product concentrator comes from the outlet of the liquid stop valve at the bottom of the lower tower section of the previous distillation tower. The condenser of the II-m distillation tower liquefies the oxygen in the product concentrator and accumulates it at the bottom of the product concentrator. When the liquid accumulation height at the bottom of the product concentrator reaches the set value, the oxygen electric heater is turned on and the evaporation power is slowly increased to the rated value. After 0.3 months of distillation, a concentration gradient is established in the product concentrator. The exhaust gas at the top of the product concentrator is returned to the air separation unit through the exhaust gas storage tank, the check valve, and the booster valve;

[0020] 10) The liquid at the bottom of the product concentration tower has reached the product isotope abundance requirement. In order to further improve the chemical purity of the product, the impurity content of the heavy component is reduced to below 0.1ppm. The gas at the bottom of the product concentration tower is introduced into the upper part of the product purification tower. The condenser of the II-m distillation tower liquefies the oxygen in the product purification tower and accumulates it at the bottom of the product purification tower. When the liquid accumulation height at the bottom of the product purification tower reaches the set value, the oxygen electric heater is turned on and the evaporation power is slowly increased to the rated value. The distillation is continued for 32 hours. The top of the product purification tower is filled with oxygen. 18 O isotope products ( 18 O abundance ≥ 90%) heavy component impurities are reduced to below 0.1ppm. It should be emphasized that in the distillation cascades II-1, II-2, ..., and II-m, the upper tower section uses structured packing, while the lower tower section uses random packing. The use of structured packing in the upper tower section can increase the evaporation steam volume of each cascade stage, thereby providing more raw liquid for the lower tower section; the use of random packing in the lower tower section can effectively reduce HETP and increase the number of theoretical plates, thereby improving the cascade enrichment efficiency.

[0021] 11) 18 During the operation of the O2 distillation and enrichment submodule, the cold nitrogen generated by the condenser of Ⅰ-1 distillation tower, Ⅰ-2 distillation tower condenser, Ⅰ-n distillation tower condenser, Ⅱ-1 distillation tower condenser, Ⅱ-2 distillation tower condenser, Ⅱ-m distillation tower condenser, and other omitted distillation tower condensers can be used as 13 CF4 distillation and enrichment submodule cold source;

[0022] 12) The device starts in the order of priority 18 O distillation enrichment subsystem, after 13 CF4 distillation enrichment subsystem, open the nitrogen reflux valve, 18 The cold nitrogen discharged during the startup of the O distillation and enrichment subsystem and the distillation balance process can be pre-cooled through the process pipeline 13 CF4 distillation enrichment subsystem, when 13When the temperature measurement point display value of the CF4 distillation and enrichment subsystem drops to the set value, the process pipeline is closed and the nitrogen stop valve is slowly opened. The cold nitrogen generated by the condenser of the Ⅰ-1 distillation tower, the condenser of the Ⅰ-2 distillation tower, the condenser of the Ⅰ-n distillation tower, the condenser of the Ⅱ-1 distillation tower, the condenser of the Ⅱ-2 distillation tower, the condenser of the Ⅱ-m distillation tower, and the condensers of other omitted distillation towers enters the rewarming heat exchanger and is reheated to 100K.

[0023] 13) After reheating, cold nitrogen (100K) enters the condenser of the i-1 distillation tower, the condenser of the i-2 distillation tower, the condenser of the is distillation tower, the condenser of the ⅱ-1 distillation tower, the condenser of the ⅱ-2 distillation tower, the condenser of the ⅱ-t distillation tower, and the condensers of other omitted distillation towers. Slowly open the CF4 feed stop valve. High-purity CF4 (V / V≥99.999%) is purified by the adsorption purification device to a purity of 7n, and then enters the i-1 distillation tower. The i-1 distillation tower condenser The condenser condenses CF4 gas, and liquid CF4 accumulates at the bottom of the i-1 distillation tower. When the liquid level at the bottom of the i-1 distillation tower reaches the specified value, the CF4 electric heater is turned on, and the evaporation power is slowly increased to the rated value. After 2.2 months of distillation, a concentration gradient is established in the i-1 distillation tower. The exhaust gas at the top of the i-1 distillation tower is stored in a CF4 storage tank for other uses. The i-1 discharge stop valve K is slowly opened, and the bottom product of the i-1 distillation tower is reheated and vaporized by heated nitrogen and then enters the i-2 distillation tower;

[0024] 14) The condenser of the i-2 distillation tower condenses CF4 gas, and liquid CF4 accumulates at the bottom of the i-2 distillation tower. When the liquid level at the bottom of the i-2 distillation tower reaches the specified value, the CF4 electric heater is turned on, and the evaporation power is slowly increased to the rated value. After 1.5 months of distillation, a concentration gradient is established in the i-2 distillation tower. The exhaust gas at the top of the i-2 distillation tower is stored in the CF4 storage tank for other uses. The i-2 discharge stop valve L is slowly opened, and the bottom product of the i-2 distillation tower is reheated and vaporized by heated nitrogen and then enters the next distillation tower. It should be noted that 13 The CF4 distillation enrichment subsystem is set up with (s+t) stages of cascade, namely i-1, i-2, ..., is, ⅱ-1, ⅱ-2, ..., ⅱ-t. The operation process of each cascade tower is the same as that of the i-1 distillation tower and the i-2 distillation tower;

[0025] 15) The feed gas of the is distillation tower comes from the outlet of the bottom liquid discharge stop valve of the upper cascade tower. The condenser of the is distillation tower condenses CF4 gas and accumulates at the bottom of the is distillation tower. When the liquid level at the bottom of the is distillation tower reaches the specified value, the CF4 electric heater is turned on and the evaporation power is slowly increased to the rated value. After one month of distillation, a concentration gradient is established in the is distillation tower. The exhaust gas at the top of the is distillation tower is stored in a CF4 storage tank for other uses. The is discharge stop valve M is slowly opened, and the bottom product of the is distillation tower is vaporized after being reheated with heated nitrogen and then enters the ⅱ-1 distillation tower;

[0026] 16) The condenser of the ⅱ-1 distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-1 distillation tower. When the liquid level at the bottom of the ⅱ-1 distillation tower reaches the specified value, the CF4 electric heater is turned on and the evaporation power is slowly increased to the rated value. After 0.7 months of distillation, a concentration gradient is established in the ⅱ-1 distillation tower (52). The waste gas at the top of the ⅱ-1 distillation tower is stored in a CF4 storage tank for other uses. The ⅱ-1 discharge stop valve N is slowly opened, and the bottom product of the ⅱ-1 distillation tower is vaporized by heating nitrogen and then enters the ⅱ-2 distillation tower;

[0027] 17) The CF4 gas condensed by the condenser of the ⅱ-2 distillation tower accumulates at the bottom of the ⅱ-2 distillation tower. When the liquid level at the bottom of the ⅱ-2 distillation tower reaches the specified value, the CF4 electric heater is turned on and the evaporation power is slowly increased to the rated value. After 0.5 months of distillation, a concentration gradient is established in the ⅱ-2 distillation tower. The exhaust gas at the top of the ⅱ-2 distillation tower is stored in a CF4 storage tank for other uses. The ⅱ-2 discharge stop valve P is slowly opened, and the bottom product of the ⅱ-2 distillation tower is vaporized after being reheated by heated nitrogen and then enters the ⅱ-t distillation tower;

[0028] 18) The condenser of the ⅱ-t distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-t distillation tower. When the liquid level at the bottom of the ⅱ-t distillation tower reaches the specified value, the CF4 electric heater is turned on and the evaporation power is slowly increased to the rated value. After 0.2 months of distillation, a concentration gradient is established in the ⅱ-t distillation tower. The exhaust gas at the top of the ⅱ-t distillation tower is stored in a CF4 storage tank for other uses. The bottom of the ⅱ-t distillation tower is used to obtain high-abundance 13 CF4 products.

[0029] As a preference: 13 The CF4 distillation enrichment subsystem adopts structured packing in the first s stage cascade and random packing in the last t stage cascade. The structured packing in the first s stage can remove a large amount of impurity 12CF4 and produce a large amount of crude oil quickly. 13 CF4 gas; random packing is used in the last stage to achieve high efficiency concentration 13 CF4, improve product 13 CF4 yield.

[0030] As a preferred method, part (P, 5-7% of the total amount) of the cold nitrogen at the outlet of the reheating heat exchanger is heated by the environment and then used as 13 The CF4 distillation tower bottom liquid heating gas is used to vaporize the bottom liquid. After heating the bottom liquid, it returns to the outlet of the reheating heat exchanger. When the cold nitrogen at the outlet of the reheating heat exchanger cannot provide enough cooling capacity to 13 When using the CF4 distillation and enrichment subsystem, air separation nitrogen can be added to the outlet of the rewarming heat exchanger.

[0031] The present invention relates to a dual stable isotope co-production device and a method for using the same. 18 The boiling point of O2 (89.94K, 1 bar) is lower than 13CF4 (145.3K, 1 bar), 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source, to achieve 13 C and 18 Highly efficient co-production of O stable isotopes, specifically: ① 18 The O2 enrichment submodule uses atmospheric pressure and low temperature distillation to continuously accumulate the rich O2 at the bottom of the distillation tower. 18 O liquid oxygen, achieved by connecting the front and rear stages in series 18 O liquid oxygen enrichment; ② 18 The O2 enrichment submodule cascade adopts a front-to-back series mode. The upper section of each distillation tower is composed of parallel tubes, and the lower section is composed of parallel tubes. The number of parallel tubes in the upper and lower sections is inconsistent, that is, the number of upper distillation tower sections is greater than that of lower distillation tower sections. The ratio of the number of upper and lower tower sections is x / y (value range, 2:1 to 4:1); ③ 18 The cooling source of the O2 distillation and enrichment submodule is liquid nitrogen (80K, 1 bar), and the cold nitrogen is evaporated to 13 CF4 distillation enrichment submodule;④ 18 The cold nitrogen in the O2 distillation and enrichment module enters after being reheated (reheated to 110K) 13 CF4 distillation enrichment submodule, as 13 CF4 distillation enriches the cold source and cools the CF4 gas at the top of the distillation tower. After reheating, the cold nitrogen part is heated to 200K by the environment and then purged 13 CF4 distillation enrichment module bottom liquid outlet pipe, vaporization 13 CF4 liquid, used as the raw material for the next stage of distillation; ⑤ 13 The CF4 enrichment submodule cascade adopts a front-end and back-end series mode. Each distillation tower is composed of parallel tubes. The number of parallel tubes in the front-end and back-end distillation towers is different. The number of parallel tubes in the front-end distillation tower is more than that in the back-end distillation tower. The ratio of the number of parallel tubes in the front-end and back-end distillation towers is u / v (value range, 1:1 to 5:1). 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source, to achieve 13 C and 18 Efficient co-production of O stable isotopes increases output 18 O and 13 The abundance of C stable isotopes has the advantages of safety and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings: Figure 1 As shown, a dual stable isotope co-production device, the device consists of 18 O-enriched submodule and 13 C enriched submodule, the 18 The raw gas of the O enrichment submodule comes from air separation oxygen, which is purified by the oxygen purification device 1. The volume purity of the raw oxygen reaches 5n. The outlet of the oxygen purification device 1 is connected to the inlet of the intermediate evaporator 3 of the Ⅰ-1 distillation tower. The intermediate evaporator 3 of the Ⅰ-1 distillation tower is connected to the bottom of the upper tower section 2 of the Ⅰ-1 distillation tower and the top of the lower tower section 4 of the Ⅰ-1 distillation tower respectively. The top of the upper tower section 1 of the Ⅰ-1 distillation tower is connected to the bottom of the condenser 5 of the Ⅰ-1 distillation tower. The bottom of the lower tower section 4 of the Ⅰ-1 distillation tower is commonly connected to the inlet of the Ⅰ-1 discharge stop valve A26 and the inlet of the Ⅰ-1 liquid discharge stop valve F31. The outlet of the Ⅰ-1 discharge stop valve A26 is connected to the inlet of the intermediate evaporator 8 of the Ⅰ-2 distillation tower. The intermediate evaporator 8 of the Ⅰ-2 distillation tower is respectively connected to the bottom of the upper tower section 7 of the Ⅰ-2 distillation tower and the top of the lower tower section 9 of the Ⅰ-2 distillation tower. The top of the upper tower section 7 of the Ⅰ-2 distillation tower is connected to the bottom of the Ⅰ-2 distillation tower condenser 10. The bottom of the lower tower section 9 of the Ⅰ-2 distillation tower is commonly connected to the inlet of the Ⅰ-2 discharge stop valve B27, the inlet of the Ⅰ-2 drain stop valve G32, and the outlet of the Ⅰ-1 drain stop valve F31. The outlet of the Ⅰ-2 discharge stop valve B27 is connected to the inlet of the intermediate evaporator of the next-level distillation tower, and the outlet of the Ⅰ-2 drain stop valve G32 is connected to the bottom of the next-level distillation tower, the inlet of the bottom discharge valve of the next-level distillation tower, and the inlet of the bottom drain valve of the next-level distillation tower.

[0034] The I-2 liquid outlet stop valve B27 is connected to the inlet of the intermediate evaporator of the next stage distillation tower, the I-n intermediate evaporator 12 is connected to the bottom of the upper tower section 11 of the I-n distillation tower and the top of the lower tower section 13 of the I-n distillation tower respectively, the top of the upper tower section 11 of the I-n distillation tower is connected to the bottom of the condenser 14 of the I-n distillation tower, and the bottom of the lower tower section 13 of the I-n distillation tower is connected to the inlet of the I-n discharge stop valve C28, the inlet of the I-n discharge stop valve H33, and the upper stage distillation tower. The outlet of the tower bottom drain stop valve, the outlet of the Ⅰ-n discharge stop valve C28 is connected to the inlet of the intermediate evaporator 16 of the Ⅱ-1 distillation tower, the upper and lower evaporators 16 of the Ⅱ-1 distillation tower are respectively connected to the bottom of the upper tower section 15 of the Ⅱ-1 distillation tower and the top of the lower tower section 17 of the Ⅱ-1 distillation tower, the bottom of the lower tower section 17 of the Ⅱ-1 distillation tower is commonly connected to the inlet of the Ⅱ-1 discharge stop valve D29, the inlet of the Ⅱ-1 drain stop valve I34, and the outlet of the bottom drain stop valve H33 of the Ⅱ-n distillation tower. -1 distillation tower upper section 15 top is connected to the bottom of the condenser 18 of the distillation tower Ⅱ-1, the outlet of the discharge stop valve D29 of the distillation tower Ⅱ-2 is connected to the inlet of the intermediate evaporator 20 of the distillation tower Ⅱ-2, the upper and lower evaporators 20 of the distillation tower Ⅱ-2 are respectively connected to the bottom of the upper section 19 of the distillation tower Ⅱ-2 and the top of the lower section 21 of the distillation tower Ⅱ-2, the bottom of the lower section 21 of the distillation tower Ⅱ-2 is commonly connected to the inlet of the discharge stop valve E30 of the distillation tower Ⅱ-2, the inlet of the liquid discharge stop valve J35 of the distillation tower Ⅱ-2, and the inlet of the liquid discharge stop valve J36 of the distillation tower Ⅱ-2. 1 distillation tower bottom drain stop valve I34 outlet, Ⅱ-2 drain stop valve J35 outlet safe emptying, Ⅱ-2 distillation tower upper section 19 top connected to Ⅱ-2 distillation tower condenser 22, the Ⅱ-2 discharge stop valve E30 outlet is connected to the next level distillation tower intermediate evaporator inlet, the product concentration tower 23 feed port is connected to the upper level distillation tower discharge stop valve outlet, the product concentration tower 23 outlet is connected to the product purification tower 24 middle feed port, the product purification tower 24 upper discharge port outlet 18 The top of the O2 product concentration tower 23 and the top of the product purification tower 24 are connected to the bottom of the II-m distillation tower condenser 25.

[0035] The exhaust port of the Ⅰ-1 distillation tower condenser 5, the exhaust port of the Ⅰ-2 distillation tower condenser 10, the exhaust port of the Ⅰ-n distillation tower condenser 14, the exhaust port of the Ⅱ-1 distillation tower condenser 18, the exhaust port of the Ⅱ-2 distillation tower condenser 22, the exhaust port of the Ⅱ-m distillation tower condenser 25, and the exhaust ports of other omitted distillation tower condensers are commonly connected to the inlet of the waste gas storage tank 60, the outlet of the waste gas storage tank 60 is connected to the inlet of the check valve 36, the outlet of the check valve 36 is connected to the inlet of the boosting valve 37, and the outlet of the boosting valve 37 is connected to the raw oxygen outlet of the air separation ASP. The bottom of the lower tower section 9 of the Ⅰ-1 distillation tower, the bottom of the lower tower section 9 of the Ⅰ-2 distillation tower, the bottom of the lower tower section 13 of the Ⅰ-n distillation tower, the bottom of the lower tower section 17 of the Ⅱ-1 distillation tower, the bottom of the lower tower section 21 of the Ⅱ-2 distillation tower, the bottom of the product concentration tower 23, and the bottom of the product purification tower 24 are all provided with oxygen electric heaters.

[0036] The cold nitrogen outlet of the Ⅰ-1 distillation tower condenser 5, the cold nitrogen outlet of the Ⅰ-2 distillation tower condenser 10, the cold nitrogen outlet of the Ⅰ-n distillation tower condenser 14, the cold nitrogen outlet of the Ⅱ-1 distillation tower condenser 18, the cold nitrogen outlet of the Ⅱ-2 distillation tower condenser 22, the cold nitrogen outlet of the Ⅱ-m distillation tower condenser 25, and the cold nitrogen outlets of other omitted distillation tower condensers are connected to the inlet of the nitrogen stop valve 41, and the outlet of the nitrogen stop valve 41 is connected to the inlet of the retemperature heat exchanger 42. The nitrogen at the outlet of the retemperature heat exchanger 42 is divided into two streams: ① as a heat source P, purging and vaporizing 13 The CF4 enrichment distillation tower bottom liquid is vaporized 13 CF4 is used as the raw material for the next stage of distillation; ② directly enters 13 CF4 enrichment distillation condenser, as a cold source, needs to pay attention to the following: ① Nitrogen vaporization 13 CF4 then merges with ②; the liquid nitrogen inlet of Ⅰ-1 distillation tower condenser 5, the liquid nitrogen inlet of Ⅰ-2 distillation tower condenser 10, the liquid nitrogen inlet of Ⅰ-n distillation tower condenser 14, the liquid nitrogen inlet of Ⅱ-1 distillation tower condenser 18, the liquid nitrogen inlet of Ⅱ-2 distillation tower condenser 22, and the liquid nitrogen inlet of Ⅱ-m distillation tower condenser 25 are commonly connected to the outlet of liquid nitrogen pump 39, the inlet of liquid nitrogen pump 39 is connected to the outlet of liquid nitrogen tank 38, the inlet of liquid nitrogen tank 38 is connected to the outlet of liquid nitrogen stop valve P65, and the inlet of liquid nitrogen stop valve P65 is connected to air separation ASP liquid nitrogen.

[0037] described 13 The raw material of the C enrichment submodule comes from high-purity CF4 cylinder gas, which enters the adsorption purification device 43 after passing through the adsorption purification device 43. 13 CF4 distillation submodule, the outlet of the adsorption purification device 43 is connected to the inlet of the CF4 feed stop valve 44, the outlet of the CF4 feed stop valve 44 is connected to the feed port of the i-1 distillation tower 45, the top of the i-1 distillation tower 45 is connected to the bottom of the i-1 distillation tower condenser 46, the bottom of the i-1 distillation tower 45 is connected to the inlet of the i-1 discharge stop valve K61, the outlet of the i-1 discharge stop valve K61 is connected to the feed port of the i-2 distillation tower 66, the top of the i-2 distillation tower 66 is connected to the bottom of the i-2 distillation tower condenser 49, the bottom of the i-2 distillation tower 66 is connected to the inlet of the i-2 discharge stop valve L62, and the outlet of the i-2 discharge stop valve L62 is connected to the next level 13 CF4 distillation tower feed port, is distillation tower 50 feed port connected to the previous level 13 The outlet of the CF4 distillation tower discharge stop valve, the top of the is distillation tower 50 is connected to the bottom of the is distillation tower condenser 51, the bottom of the is distillation tower 50 is connected to the inlet of the is discharge stop valve M63, and the outlet of the is discharge stop valve M63 is connected to the feed inlet of the ⅱ-1 distillation tower 52.

[0038] The top of the ⅱ-1 distillation tower 52 is connected to the bottom of the ⅱ-1 distillation tower condenser 53, the bottom of the ⅱ-1 distillation tower 52 is connected to the inlet of the ⅱ-1 discharge stop valve N64, the outlet of the ⅱ-1 discharge stop valve N64 is connected to the feed port of the ⅱ-2 distillation tower, the top of the ⅱ-2 distillation tower 54 is connected to the bottom of the ⅱ-2 distillation tower condenser 55, the bottom of the ⅱ-2 distillation tower 54 is connected to the inlet of the ⅱ-2 discharge stop valve P65, and the outlet of the ⅱ-2 discharge stop valve P65 is connected to the next level 13 CF4 distillation tower feed port, ⅱ-t concentration tower 56 feed port connected to the previous level 13 CF4 distillation tower discharge stop valve outlet, ⅱ-t concentration tower 56 top connected to ⅱ-t distillation tower condenser 57 bottom, ⅱ-t distillation tower 56 bottom outlet 13 Product C.

[0039] The nitrogen inlet of the i-1 rectifying tower condenser 46, the nitrogen inlet of the i-2 rectifying tower condenser 49, the nitrogen inlet of the is rectifying tower condenser 51, the nitrogen inlet of the ⅱ-1 rectifying tower condenser 53, the nitrogen inlet of the ⅱ-2 rectifying tower condenser 55, and the nitrogen inlet of the ⅱ-t rectifying tower condenser 57 are connected together to the outlet of the rewarming heat exchanger 42, and the nitrogen outlet of the i-1 rectifying tower condenser 46, the nitrogen outlet of the i-2 rectifying tower condenser 49, the nitrogen outlet of the is rectifying tower condenser 51, the nitrogen outlet of the ⅱ-1 rectifying tower condenser 53, the nitrogen outlet of the ⅱ-2 rectifying tower condenser 55, the nitrogen outlet of the ⅱ-t rectifying tower condenser 57, and the nitrogen outlets of the other omitted rectifying tower condensers are connected together to the nitrogen The gas reflux valve 59 inlet and the nitrogen reflux valve 59 outlet are connected to the air separation ASP nitrogen inlet, the i-1 distillation tower condenser 46 exhaust port, the i-2 distillation tower condenser 49 exhaust port, the is distillation tower condenser 51 exhaust port, the ⅱ-1 distillation tower condenser 53 exhaust port, the ⅱ-2 distillation tower condenser 55 exhaust port, the ⅱ-2 distillation tower condenser 57 exhaust port, and the exhaust ports of other omitted distillation tower condensers are commonly connected to the CF4 storage tank 58, the i-1 distillation tower 45, the i-2 distillation tower 66, the is distillation tower 50, the ⅱ-1 distillation tower 52, the ⅱ-2 distillation tower 54, the ⅱ-t distillation tower 5, and other omitted distillation towers, and a CF4 electric heater 47 is set at the bottom.

[0040] A method for using a dual stable isotope co-production device comprises the following steps:

[0041] 1) Before starting the system, it is necessary to evacuate the system, open the discharge stop valve A26 to the discharge stop valve E30, the boost valve 37, the discharge stop valve K61 to the discharge stop valve P65, and the nitrogen stop valve 41, close the drain stop valve F31 to the drain stop valve J35, evacuate the system material pipeline to less than 10pa, and close all valves. Before starting the system, it is necessary to pre-cool the entire device, slowly open the liquid nitrogen stop valve P65, and the air separation atmospheric pressure liquid nitrogen enters the liquid nitrogen tank 38. After the liquid level of the liquid nitrogen tank 38 reaches the specified value, start the liquid nitrogen pump 39, Ⅰ-1 distillation tower condenser 5, Ⅰ-2 distillation tower condenser 10, Ⅰ-n distillation tower condenser 14, Ⅱ-1 distillation tower condenser 18, Ⅱ-2 distillation tower condenser 22, Ⅱ-m distillation tower condenser 25, and other He omitted the distillation tower condenser, and at the same time, liquid nitrogen was introduced, and the device began to cool down. When the temperature value displayed by the system temperature measuring point dropped to the set value, the air separation raw oxygen was purified by the oxygen purification device 1 and then entered the intermediate evaporator 3 of the I-1 distillation tower. It was condensed by the condenser 5 of the I-1 distillation tower and accumulated at the bottom of the lower tower section 4 of the I-1 distillation tower. When the accumulated liquid in the lower tower section 4 of the I-1 distillation tower submerged the entire lower tower section 4 of the I-1 distillation tower, the oxygen electric heater 6 was turned on and the evaporation power was slowly increased to the rated value. After 2.5 months of distillation, a concentration gradient was established between the upper tower section 2 of the I-1 distillation tower and the lower tower section 4 of the I-1 distillation tower. At this time, the booster valve 37 was slowly opened, and the exhaust gas from the top of the upper tower section 2 of the I-1 distillation tower passed through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37 and returned to the air separation device 40.

[0042] 2) Opening the I-1 discharge stop valve A26, the bottom product of the lower section 4 of the I-1 distillation tower is discharged from the cold box for reheating and vaporization, and then enters the intermediate evaporator 8 of the I-2 distillation tower. The oxygen in the tower is liquefied by the condenser 10 of the I-2 distillation tower and accumulates at the bottom of the lower section 9 of the I-2 distillation tower. When the liquid in the lower section 9 of the I-2 distillation tower submerges the entire lower section 9 of the I-2 distillation tower, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. After 1.5 months of distillation, a concentration gradient is established between the upper section 7 of the I-2 distillation tower and the lower section 9 of the I-2 distillation tower. The exhaust gas from the top of the upper section 2 of the I-2 distillation tower is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37;

[0043] 3) Open the I-2 discharge stop valve B27, and the bottom product of the lower tower section 9 of the I-2 distillation tower is discharged from the cold box for reheating and vaporization, and then enters the next level distillation tower. It is worth noting that in the device of the present invention, 18 The O enrichment submodule is divided into a structured packing system and a random packing system. The structured packing system is cascaded to Ⅰ-1, Ⅰ-2, ..., Ⅰ-n, with a total of n stages; the random packing system is cascaded to Ⅱ-1, Ⅱ-2, ..., Ⅱ-m, with a total of m stages. The operation process of each cascade tower of the structured packing system is the same as that of the Ⅰ-1 distillation tower and the Ⅰ-2 distillation tower.

[0044] 4) The feed to the intermediate evaporator 12 of the I-n distillation tower is from the outlet of the liquid outlet stop valve at the bottom of the lower tower section of the previous distillation tower. The condenser 14 of the I-n distillation tower liquefies the oxygen in the tower and accumulates it at the bottom of the lower tower section 13 of the I-n distillation tower. When the accumulated liquid in the lower tower section 13 of the I-n distillation tower submerges the entire lower tower section 13 of the I-n distillation tower, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. After one month of distillation, a concentration gradient is established between the upper tower section 11 of the I-n distillation tower and the lower tower section 13 of the I-n distillation tower. The exhaust gas from the top of the upper tower section 11 of the I-n distillation tower is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37;

[0045] 5) Open the I-n discharge stop valve C28, and the bottom product of the lower tower section 13 of the I-n distillation tower is discharged from the cold box for reheating and vaporization, and then enters the random packing system (II-1, II-2, ..., II-m);

[0046] 6) First, the product at the bottom of the lower section 13 of the II-n distillation tower is reheated and vaporized after exiting the cold box. The product then enters the intermediate evaporator 16 of the II-1 distillation tower. The oxygen in the tower is liquefied by the condenser 18 of the II-1 distillation tower and accumulates at the bottom of the lower section 17 of the II-1 distillation tower. When the accumulated liquid in the lower section 17 of the II-1 distillation tower completely submerges the entire lower section 17 of the II-1 distillation tower, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. After 0.8 months of distillation, a concentration gradient is established between the upper section 15 of the II-1 distillation tower and the lower section 17 of the II-1 distillation tower. The exhaust gas at the top of the upper section 15 of the II-1 distillation tower is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37.

[0047] 7) Open the II-1 discharge stop valve D29, and the product at the bottom of the lower section 17 of the II-1 distillation tower is discharged from the cold box for reheating and vaporization, and enters the intermediate evaporator 20 of the II-2 distillation tower. The oxygen in the tower is liquefied by the condenser 22 of the II-2 distillation tower and accumulates at the bottom of the lower section 21 of the II-2 distillation tower. When the liquid in the lower section 21 of the II-2 distillation tower submerges the entire lower section 21 of the II-2 distillation tower, turn on the oxygen electric heater 6 and slowly increase the evaporation power to the rated value. After 0.6 months of distillation, a concentration gradient is established between the upper section 19 of the II-2 distillation tower and the lower section 21 of the II-2 distillation tower. The exhaust gas at the top of the upper section 19 of the II-2 distillation tower passes through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37 and returns to the air separation unit 40;

[0048] 8) Open the II-2 discharge stop valve E30, and the bottom product of the lower tower section 21 of the II-2 distillation tower is discharged from the cold box for reheating and vaporization, and then sent to the next distillation tower. It is worth noting that in the device of the present invention, the random packing system is cascaded to II-1, II-2, ..., I-m, with a total of m stages. The operation process of each stage of the random packing system cascade tower is consistent with that of the II-1 distillation tower and the II-2 distillation tower;

[0049] 9) The feedstock for the product concentrator 23 comes from the outlet of the liquid stop valve at the bottom of the lower tower section of the upper distillation tower. The II-m distillation tower condenser 25 liquefies the oxygen in the product concentrator 23 and accumulates it at the bottom of the product concentrator 23. When the liquid accumulation height at the bottom of the product concentrator 23 reaches the set value, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. After 0.3 months of distillation, a concentration gradient is established in the product concentrator 23. The exhaust gas from the top of the product concentrator 23 is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37.

[0050] 10) The liquid at the bottom of the product concentration tower 23 has reached the product isotope abundance requirement. In order to further improve the chemical purity of the product, the content of heavy component impurities is reduced to below 0.1ppm. The gas at the bottom of the product concentration tower 23 is introduced into the upper part of the product purification tower 24. The II-m distillation tower condenser 25 liquefies the oxygen in the product purification tower 24 and accumulates it at the bottom of the product purification tower 24. When the liquid accumulation height at the bottom of the product purification tower 24 reaches the set value, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. The distillation is continued for 32 hours. The top of the product purification tower 24 is heated to 100°C. 18 O isotope products ( 18 O abundance ≥ 90%) heavy component impurities are reduced to below 0.1ppm. It should be emphasized that in the distillation cascades II-1, II-2, ..., and II-m, the upper tower section uses structured packing, while the lower tower section uses random packing. The use of structured packing in the upper tower section can increase the evaporation steam volume of each cascade stage, thereby providing more raw liquid for the lower tower section; the use of random packing in the lower tower section can effectively reduce HETP and increase the number of theoretical plates, thereby improving the cascade enrichment efficiency.

[0051] 11) 18 During the operation of the O2 distillation and enrichment submodule, the cold nitrogen generated by the condenser 5 of the Ⅰ-1 distillation tower, the condenser 10 of the Ⅰ-2 distillation tower, the condenser 14 of the Ⅰ-n distillation tower, the condenser 18 of the Ⅱ-1 distillation tower, the condenser 22 of the Ⅱ-2 distillation tower, the condenser 25 of the Ⅱ-m distillation tower, and the condensers of the other omitted distillation towers can be used as 13 CF4 distillation and enrichment submodule cold source;

[0052] 12) The device starts in the order of priority 18 O distillation enrichment subsystem, after 13 CF4 distillation enrichment subsystem, open nitrogen reflux valve 59, 18 The cold nitrogen discharged during the startup of the O distillation and enrichment subsystem and the distillation balance process can be pre-cooled through the process pipeline 13 CF4 distillation enrichment subsystem, when 13The temperature measurement point display value of the CF4 distillation and enrichment subsystem drops to the set value, the process pipeline is closed, and the nitrogen stop valve 41 is slowly opened. The cold nitrogen generated by the Ⅰ-1 distillation tower condenser 5, the Ⅰ-2 distillation tower condenser 10, the Ⅰ-n distillation tower condenser 14, the Ⅱ-1 distillation tower condenser 18, the Ⅱ-2 distillation tower condenser 22, the Ⅱ-m distillation tower condenser 25, and other omitted distillation tower condensers enters the rewarming heat exchanger 42, and the cold nitrogen is reheated to 100K;

[0053] 13) After reheating, the cold nitrogen (100K) enters the i-1 distillation tower condenser 46, the i-2 distillation tower condenser 49, the is distillation tower condenser 51, the ⅱ-1 distillation tower condenser 53, the ⅱ-2 distillation tower condenser 55, the ⅱ-t distillation tower condenser 57, and other omitted distillation tower condensers, and slowly opens the CF4 feed stop valve 44. High-purity CF4 (V / V ≥ 99.999%) is purified by the adsorption purification device 43 to a purity of 7n, and then enters the i-1 distillation tower 45 and the i-1 distillation tower condenser. 46 condenses CF4 gas, and liquid CF4 accumulates at the bottom of the i-1 distillation tower 45. When the liquid level at the bottom of the i-1 distillation tower 45 reaches the specified value, the CF4 electric heater 47 is turned on, and the evaporation power is slowly increased to the rated value. After 2.2 months of distillation, a concentration gradient is established in the i-1 distillation tower 45. The exhaust gas at the top of the i-1 distillation tower 45 is stored in the CF4 storage tank 58 for other uses. The i-1 discharge stop valve K61 is slowly opened, and the bottom product of the i-1 distillation tower 45 is reheated and vaporized by the heated nitrogen P and then enters the i-2 distillation tower 66;

[0054] 14) The condenser 49 of the i-2 distillation tower condenses CF4 gas, and liquid CF4 accumulates at the bottom of the i-2 distillation tower 66. When the liquid level at the bottom of the i-2 distillation tower 66 reaches the specified value, the CF4 electric heater 47 is turned on, and the evaporation power is slowly increased to the rated value. After 1.5 months of distillation, a concentration gradient is established in the i-2 distillation tower 66. The exhaust gas at the top of the i-2 distillation tower 66 is stored in the CF4 storage tank 58 for other uses. The i-2 discharge stop valve L62 is slowly opened, and the bottom product of the i-2 distillation tower 66 is reheated and vaporized by the heated nitrogen P and then enters the next distillation tower. It should be noted that 13 The CF4 distillation enrichment subsystem is set up with (s+t) stages of cascade, namely i-1, i-2, ..., is, ⅱ-1, ⅱ-2, ..., ⅱ-t. The operation process of each cascade tower is the same as that of the i-1 distillation tower and the i-2 distillation tower;

[0055] 15) The feed gas of the is distillation tower 50 comes from the outlet of the bottom liquid outlet stop valve of the upper cascade tower. The is distillation tower condenser 51 condenses CF4 gas and accumulates at the bottom of the is distillation tower 50. When the liquid level at the bottom of the is distillation tower 50 reaches the specified value, the CF4 electric heater 47 is turned on and the evaporation power is slowly increased to the rated value. After one month of distillation, a concentration gradient is established in the is distillation tower 50. The exhaust gas at the top of the is distillation tower 50 is stored in the CF4 storage tank 58 for other uses. The is discharge stop valve M63 is slowly opened, and the bottom product of the is distillation tower 50 is reheated and vaporized by the heated nitrogen P and then enters the ⅱ-1 distillation tower 52;

[0056] 16) The condenser 53 of the ⅱ-1 distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-1 distillation tower 52. When the liquid level at the bottom of the ⅱ-1 distillation tower 52 reaches the specified value, the CF4 electric heater 47 is turned on and the evaporation power is slowly increased to the rated value. After 0.7 months of distillation, a concentration gradient is established in the ⅱ-1 distillation tower 52. The exhaust gas at the top of the ⅱ-1 distillation tower 52 is stored in the CF4 storage tank 58 for other uses. The ⅱ-1 discharge stop valve N64 is slowly opened, and the bottom product of the ⅱ-1 distillation tower 52 is reheated and vaporized by the heated nitrogen P and then enters the ⅱ-2 distillation tower 54;

[0057] 17) The condenser 55 of the ⅱ-2 distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-2 distillation tower 54. When the liquid level at the bottom of the ⅱ-2 distillation tower 54 reaches the specified value, the CF4 electric heater 47 is turned on and the evaporation power is slowly increased to the rated value. After 0.5 months of distillation, a concentration gradient is established in the ⅱ-2 distillation tower 54. The exhaust gas at the top of the ⅱ-2 distillation tower 54 is stored in the CF4 storage tank 58 for other uses. The ⅱ-2 discharge stop valve P65 is slowly opened, and the bottom product of the ⅱ-2 distillation tower 52 is reheated and vaporized by the heated nitrogen P and then enters the ⅱ-t distillation tower 56;

[0058] 18) The condenser 57 of the ⅱ-t distillation tower condenses the CF4 gas and accumulates at the bottom of the ⅱ-t distillation tower 56. When the liquid level at the bottom of the ⅱ-t distillation tower 56 reaches the specified value, the CF4 electric heater 47 is turned on and the evaporation power is slowly increased to the rated value. After 0.2 months of distillation, the concentration gradient is established in the ⅱ-t distillation tower 56. The exhaust gas at the top of the ⅱ-t distillation tower 56 is stored in the CF4 storage tank 58 for other use. The bottom of the ⅱ-t distillation tower 56 is obtained with high abundance. 13 CF4 products.

[0059] described 13 The CF4 distillation enrichment subsystem adopts structured packing in the first s stage cascade and random packing in the last t stage cascade. The structured packing in the first s stage can remove a large amount of impurity 12CF4 and produce a large amount of crude oil quickly. 13 CF4 gas; random packing is used in the last stage to achieve high efficiency concentration 13 CF4, improve product 13 CF4 yield.

[0060] A portion (P, 5-7% of the total amount) of the cold nitrogen at the outlet of the reheating heat exchanger 42 is heated by the environment and then used as 13 The CF4 distillation tower bottom liquid heating gas is used to vaporize the tower bottom liquid. After heating the tower bottom liquid, it returns to the outlet of the reheating heat exchanger 42. When the cold nitrogen at the outlet of the reheating heat exchanger 42 cannot provide enough cooling capacity to 13 When the CF4 distillation and enrichment subsystem is in operation, air separation nitrogen can be added to the outlet of the rewarming heat exchanger 42.

[0061] The present invention relates to a 13 C. 18 O stable isotope co-production technology and equipment, using 18 The boiling point of O2 (89.94K, 1 bar) is lower than 13 CF4 (145.3K, 1 bar), 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source, to achieve 13 C and 18 Highly efficient co-production of O stable isotopes, specifically: ① 18 The O2 enrichment submodule uses atmospheric pressure and low temperature distillation to continuously accumulate the rich O2 at the bottom of the distillation tower. 18 O liquid oxygen, achieved by connecting the front and rear stages in series 18 O liquid oxygen enrichment; ② 18 The O2 enrichment submodule cascade adopts a front-to-back series mode. The upper section of each distillation tower is composed of parallel tubes, and the lower section is composed of parallel tubes. The number of parallel tubes in the upper and lower sections is inconsistent, that is, the number of upper distillation tower sections is greater than that of lower distillation tower sections. The ratio of the number of upper and lower tower sections is x / y (value range, 2:1 to 4:1); ③ 18 The cooling source of the O2 distillation and enrichment submodule is liquid nitrogen (80K, 1 bar), and the cold nitrogen is evaporated to 13 CF4 distillation enrichment submodule;④ 18 The cold nitrogen in the O2 distillation and enrichment module enters after being reheated (reheated to 110K) 13 CF4 distillation enrichment submodule, as 13 CF4 distillation enriches the cold source and cools the CF4 gas at the top of the distillation tower. After reheating, the cold nitrogen part is heated to 200K by the environment and then purged 13 CF4 distillation enrichment module bottom liquid outlet pipe, vaporization 13 CF4 liquid, used as the raw material for the next stage of distillation; ⑤ 13The CF4 enrichment submodule cascade adopts a front-end and back-end series mode. Each distillation tower is composed of parallel tubes. The number of parallel tubes in the front-end and back-end distillation towers is different. The number of parallel tubes in the front-end distillation tower is more than that in the back-end distillation tower. The ratio of the number of parallel tubes in the front-end and back-end distillation towers is u / v (value range, 1:1~5:1).

[0062] in, Figure 1 The figure shows a schematic diagram of the dual stable isotope co-production technology and device of the present invention. The components indicated by the serial numbers in the figure are as follows:

[0063] 1. Oxygen purification device, 2. Upper section of Ⅰ-1 distillation tower, 3. Intermediate evaporator of Ⅰ-1 distillation tower, 4. Lower section of Ⅰ-1 distillation tower, 5. Condenser of Ⅰ-1 distillation tower, 6. Oxygen electric heater, 7. Upper section of Ⅰ-2 distillation tower, 8. Intermediate evaporator of Ⅰ-2 distillation tower, 9. Lower section of Ⅰ-2 distillation tower, 10. Condenser of Ⅰ-2 distillation tower, 11. Upper section of Ⅰ-n distillation tower, 12. Ⅰ- n Distillation tower intermediate evaporator, 13, Ⅰ-n distillation tower lower tower section, 14, Ⅰ- n Distillation tower condenser, 15, Ⅱ-1 distillation tower upper section, 16, Ⅱ-1 distillation tower intermediate evaporator, 17, Ⅱ-1 distillation tower lower section, 18, Ⅱ-1 distillation tower condenser, 19, Ⅱ-2 distillation tower upper section, 20, Ⅱ-2 distillation tower intermediate evaporator, 21, Ⅱ-2 distillation tower lower section, 22, Ⅱ-2 distillation tower condenser, 23, product concentration tower, 24, product purification tower, 25, Ⅱ- m Distillation tower condenser, 26, Ⅰ-1 discharge stop valve, 27, Ⅰ-2 discharge stop valve, 28, Ⅰ- n Discharge stop valve, 29, Ⅱ-1 discharge stop valve D, 30, Ⅱ-2 discharge stop valve, 31, Ⅰ-1 discharge stop valve, 32, Ⅰ-2 discharge stop valve, 33, Ⅰ- n Drain stop valve, 34, Ⅱ-1 drain stop valve, 35, Ⅱ-2 drain stop valve, 36, check valve, 37, booster valve, 38, liquid nitrogen tank, 39, liquid nitrogen pump, 40, air separation equipment ASP, 41, nitrogen stop valve, 42, reheating heat exchanger, 43, adsorption purification device, 44, CF4 feed stop valve, 45, i-1 distillation tower, 46, i-1 distillation tower condenser, 47, CF4 electric heater, 48, nitrogen safety valve, 49, i-2 distillation tower condenser, 50, i- s Distillation tower, 51, i- s Distillation tower condenser, 52, ⅱ-1 distillation tower, 53, ⅱ-1 distillation tower condenser, 54, ⅱ-2 distillation tower, 55, ⅱ-2 distillation tower condenser, 56, ⅱ- t Concentration tower, 57, ⅱ- tDistillation tower condenser, 58, CF4 storage tank, 59, nitrogen reflux valve, 60, waste gas storage tank, 61, i-1 discharge stop valve, 62, i-2 discharge stop valve, 63, i- s Discharge stop valve, 64, ⅱ-1 discharge stop valve, 65, liquid nitrogen stop valve, 66, i-2 distillation tower.

[0064] like Figure 1 As shown, the device of the present invention is used to synchronously separate 18 O. 13 C stable isotope. 18 The cold source liquid nitrogen (80K, 1 bar) of the O2 distillation enrichment submodule evaporates and the cold nitrogen gas is reheated (reheated to 110K) and enters 13 CF4 distillation enrichment submodule, as 13 CF4 distillation enriches the cold source and cools the CF4 gas at the top of the distillation tower.

[0065] Embodiments of the present invention

[0066] The present invention 13 C. 18 O stable isotope co-production technology and equipment for efficient synchronous production 13 C. 18 O stable isotope. Before starting the system, evacuate the system. Open valves 26 to 30, 37, 61 to 65, and 41. Close valves 31 to 35. Evacuate the system material pipeline to less than 10 Pa. Close all valves.

[0067] Before starting the system, the entire device must be pre-cooled. Slowly open the liquid nitrogen stop valve P65, and the atmospheric pressure liquid nitrogen from the air separation enters the liquid nitrogen tank 38. After the liquid level in the liquid nitrogen tank 38 reaches the specified value, start the liquid nitrogen pump 39, Ⅰ-1 distillation tower condenser 5, Ⅰ-2 distillation tower condenser 10, Ⅰ- n Distillation tower condenser 14, II-1 distillation tower condenser 18, II-2 distillation tower condenser 22, II- m Liquid nitrogen is simultaneously introduced into the distillation tower condenser 25, and the unit begins cooling. When the system temperature reading drops to the set value, the air separation feed oxygen is purified by the oxygen purification unit 1 and then enters the intermediate evaporator 3 of the I-1 distillation tower. It is then condensed by the I-1 distillation tower condenser 5 and accumulates at the bottom of the I-1 distillation tower lower section 4. When the accumulated liquid in the I-1 distillation tower lower section 4 completely submerges the entire I-1 distillation tower lower section 4, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. After 2.5 months of distillation, a concentration gradient is established between the I-1 distillation tower upper section 2 and the I-1 distillation tower lower section 4. At this point, the booster valve 37 is slowly opened, and the exhaust gas from the top of the I-1 distillation tower upper section 2 is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37.

[0068] Next, the I-1 discharge shutoff valve A26 is opened, and the bottom product of the lower section 4 of the I-1 distillation tower exits the cold box for reheating and vaporization before entering the intermediate evaporator 8 of the I-2 distillation tower. The oxygen in the I-2 distillation tower condenser 10 liquefies the oxygen, which accumulates at the bottom of the lower section 9 of the I-2 distillation tower. When the accumulated liquid in the lower section 9 of the I-2 distillation tower completely submerges the entire section, the oxygen electric heater 6 is turned on, and the evaporation power is slowly increased to the rated value. After 1.5 months of distillation, a concentration gradient is established between the upper section 7 of the I-2 distillation tower and the lower section 9 of the I-2 distillation tower. The exhaust gas from the top of the upper section 2 of the I-2 distillation tower is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37.

[0069] Further, open the I-2 discharge stop valve B27, and the bottom product of the lower tower section 9 of the I-2 distillation tower will be discharged from the cold box for reheating and vaporization, and then enter the next level distillation tower. It is worth noting that in the device of the present invention, 18 The O enrichment submodule is divided into a structured packing system and a random packing system, wherein the structured packing system cascade is set as Ⅰ-1, Ⅰ-2, ..., Ⅰ- n , a total of n Level; random packing system cascade is set as Ⅱ-1, Ⅱ-2, ..., Ⅱ- m , a total of m The operation process of each stage of the cascade tower in the structured packing system is the same as that of the Ⅰ-1 distillation tower and Ⅰ-2 distillation tower.

[0070] Further, I- n The feed to the intermediate evaporator 12 of the distillation tower comes from the outlet of the liquid stop valve at the bottom of the lower tower section of the upper distillation tower, Ⅰ- n The distillation tower condenser 14 liquefies the oxygen in the tower and accumulates in I- n The bottom of the distillation tower section 13. n The lower section 13 of the distillation tower is filled with liquid and the entire Ⅰ- n In the lower section 13 of the distillation tower, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. After one month of distillation, Ⅰ- n Distillation tower upper section 11 and Ⅰ- n The concentration gradient is established in the lower section 13 of the distillation tower, Ⅰ- n The waste gas from the top of the upper tower section 11 of the distillation tower returns to the air separation device 40 through the waste gas storage tank 60, the check valve 36, and the boosting valve 37.

[0071] Open Ⅰ- n Discharge stop valve C28,Ⅰ- n The bottom product of the lower tower section 13 of the distillation tower is reheated and vaporized in the cold box, and then enters the random packing system (Ⅱ-1, Ⅱ-2, ..., Ⅱ- m ).

[0072] First, I- nThe product at the bottom of the lower section 13 of the distillation tower exits the cold box, reheats, and vaporizes before entering the intermediate evaporator 16 of the II-1 distillation tower. The condenser 18 of the II-1 distillation tower liquefies the oxygen within the tower, which accumulates at the bottom of the lower section 17 of the II-1 distillation tower. When the accumulated liquid in the lower section 17 of the II-1 distillation tower completely submerges the entire tower, the oxygen heater 6 is turned on, and the evaporation power is slowly increased to the rated value. After 0.8 months of distillation, a concentration gradient is established between the upper section 15 of the II-1 distillation tower and the lower section 17 of the II-1 distillation tower. The exhaust gas from the top of the upper section 15 of the II-1 distillation tower is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37.

[0073] Next, the II-1 discharge shutoff valve D29 is opened, and the product at the bottom of the lower section 17 of the II-1 distillation tower exits the cold box, reheats, and vaporizes. It then enters the intermediate evaporator 20 of the II-2 distillation tower. The oxygen in the tower is liquefied by the condenser 22 of the II-2 distillation tower, and accumulates at the bottom of the lower section 21 of the II-2 distillation tower. When the accumulated liquid in the lower section 21 of the II-2 distillation tower completely submerges the entire lower section 21 of the II-2 distillation tower, the oxygen electric heater 6 is turned on, and the evaporation power is slowly increased to the rated value. After 0.6 months of distillation, a concentration gradient is established between the upper section 19 of the II-2 distillation tower and the lower section 21 of the II-2 distillation tower. The exhaust gas from the top of the upper section 19 of the II-2 distillation tower is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the booster valve 37.

[0074] Further, the II-2 discharge stop valve E30 is opened, and the bottom product of the lower tower section 21 of the II-2 distillation tower is discharged from the cold box for reheating and vaporization, and then goes to the next level distillation tower. It is worth noting that in the device of the present invention, the random packing system is cascaded as II-1, II-2, ..., I- m , a total of m The operation process of each stage of the cascade tower in the random packing system is consistent with that of the Ⅱ-1 distillation tower and the Ⅱ-2 distillation tower.

[0075] Furthermore, the raw material of the product concentration tower 23 comes from the outlet of the liquid stop valve at the bottom of the lower tower section of the upper distillation tower, Ⅱ- m The distillation tower condenser 25 liquefies the oxygen in the product concentrator 23, which accumulates at the bottom of the tower. When the liquid level at the bottom of the tower reaches the set value, the oxygen heater 6 is turned on, and the evaporation power is slowly increased to the rated value. After 0.3 months of distillation, a concentration gradient is established in the product concentrator 23. The exhaust gas from the top of the tower 23 is returned to the air separation unit 40 through the exhaust gas storage tank 60, the check valve 36, and the boost valve 37.

[0076] Furthermore, the liquid at the bottom of the product concentration tower 23 has reached the product isotope abundance requirement. In order to further improve the chemical purity of the product, the content of heavy component impurities is reduced to below 0.1ppm. The gas at the bottom of the product concentration tower 23 is introduced into the upper part of the product purification tower 24. mThe distillation tower condenser 25 liquefies the oxygen in the product purification tower 24 and accumulates it at the bottom of the product purification tower 24. When the liquid accumulation height at the bottom of the product purification tower 24 reaches the set value, the oxygen electric heater 6 is turned on and the evaporation power is slowly increased to the rated value. 18 O isotope products ( 18 O abundance ≥ 90%) heavy component impurities are reduced to below 0.1ppm. It should be pointed out that the random packing system distillation cascade II-1, II-2, ..., II- m The upper tower section uses structured packing, while the lower tower section uses random packing. Using structured packing in the upper tower section increases the evaporation rate of each cascade stage, thereby providing more raw liquid for the lower tower section. Using random packing in the lower tower section effectively reduces HETP, increases the number of theoretical plates, and thus improves the cascade enrichment efficiency.

[0077] 18 During the operation of the O2 distillation and enrichment submodule, Ⅰ-1 distillation tower condenser 5, Ⅰ-2 distillation tower condenser 10, Ⅰ- n Distillation tower condenser 14, II-1 distillation tower condenser 18, II-2 distillation tower condenser 22, II- m The cold nitrogen produced by the distillation tower condenser 25 and other omitted distillation tower condensers can be used as 13 Cold source of CF4 distillation and enrichment submodule.

[0078] It should be noted that the order of starting the device of the present invention is first 18 O distillation enrichment subsystem, after 13 CF4 distillation enrichment subsystem. Open nitrogen reflux valve 59, 18 The cold nitrogen discharged during the startup of the O distillation and enrichment subsystem and the distillation balance process (before the nitrogen stop valve 41) can be pre-cooled through the process pipeline 13 CF4 distillation enrichment subsystem. 13 The temperature measurement point display value of CF4 distillation enrichment subsystem drops to the set value, and the process pipeline is closed. Slowly open the nitrogen stop valve 41, Ⅰ-1 distillation tower condenser 5, Ⅰ-2 distillation tower condenser 10, Ⅰ- n Distillation tower condenser 14, II-1 distillation tower condenser 18, II-2 distillation tower condenser 22, II- m The cold nitrogen gas generated by the distillation tower condenser 25 and other omitted distillation tower condensers enters the rewarming heat exchanger 42, and the cold nitrogen gas is rewarmed to 100K.

[0079] Further, the rewarmed cold nitrogen gas (100K) enters the i-1 distillation tower condenser 46, the i-2 distillation tower condenser 49, the is distillation tower condenser 51, the ⅱ-1 distillation tower condenser 53, the ⅱ-2 distillation tower condenser 55, the ⅱ-t distillation tower condenser 57, and other omitted distillation tower condensers.

[0080] Slowly open the CF4 feed shutoff valve 44. High-purity CF4 (V / V ≥ 99.999%) is purified by adsorption purification unit 43 to a purity of 7n before entering the i-1 distillation tower 45. The i-1 distillation tower condenser 46 condenses the CF4 gas, and liquid CF4 accumulates at the bottom of the i-1 distillation tower 45. When the liquid level at the bottom of the i-1 distillation tower 45 reaches the specified value, turn on the CF4 electric heater 47 and slowly increase the evaporation power to the rated value. After 2.2 months of distillation, a concentration gradient is established in the i-1 distillation tower 45. The exhaust gas from the top of the i-1 distillation tower 45 is stored in the CF4 storage tank 58 for further use. Slowly open the i-1 discharge shutoff valve K61. The bottom product of the i-1 distillation tower 45 is reheated and vaporized by heated nitrogen P before entering the i-2 distillation tower 66.

[0081] Further, the condenser 49 of the i-2 distillation tower condenses the CF4 gas, and the liquid CF4 accumulates at the bottom of the i-2 distillation tower 66. When the liquid level at the bottom of the i-2 distillation tower 66 reaches the specified value, the CF4 electric heater 47 is turned on, and the evaporation power is slowly increased to the rated value. After 1.5 months of distillation, the i-2 distillation tower 66 establishes a concentration gradient, and the exhaust gas at the top of the i-2 distillation tower 66 is stored in the CF4 storage tank 58 for other uses. Slowly open the i-2 discharge stop valve L62, and the bottom product of the i-2 distillation tower 66 is reheated and vaporized by the heated nitrogen P and then enters the next distillation tower. It should be noted that 13 The CF4 distillation and enrichment subsystem is configured with (s+t) cascade stages, namely i-1, i-2, ..., is, ⅱ-1, ⅱ-2, ..., ⅱ-t. The operation of each cascade tower is the same as that of the i-1 and i-2 distillation towers.

[0082] Furthermore, the feed gas for the 1s distillation tower 50 comes from the outlet of the bottom liquid shutoff valve of the previous cascade tower. The 1s distillation tower condenser 51 condenses CF4 gas, which accumulates at the bottom of the 1s distillation tower 50. When the liquid level at the bottom of the 1s distillation tower 50 reaches the specified value, the CF4 electric heater 47 is turned on, and the evaporation power is slowly increased to the rated value. After one month of distillation, a concentration gradient is established in the 1s distillation tower 50. The exhaust gas from the top of the 1s distillation tower 50 is stored in the CF4 storage tank 58 for further use. The 1s discharge shutoff valve M63 is slowly opened, and the bottom product of the 1s distillation tower 50 is reheated and vaporized by heated nitrogen P before entering the ii-1 distillation tower 52.

[0083] Furthermore, the condenser 53 of the ⅱ-1 distillation tower 52 condenses CF4 gas, which accumulates at the bottom of the ⅱ-1 distillation tower 52. When the liquid level at the bottom of the ⅱ-1 distillation tower 52 reaches the specified value, the CF4 electric heater 47 is turned on, and the evaporation power is slowly increased to the rated value. After 0.7 months of distillation, a concentration gradient is established in the ⅱ-1 distillation tower 52, and the exhaust gas from the top of the ⅱ-1 distillation tower 52 is stored in the CF4 storage tank 58 for further use. The ⅱ-1 discharge shut-off valve N64 is slowly opened, and the bottom product of the ⅱ-1 distillation tower 52 is reheated and vaporized by the heated nitrogen P before entering the ⅱ-2 distillation tower 54.

[0084] Furthermore, the condenser 55 of the ii-2 distillation tower condenses CF4 gas, which accumulates at the bottom of the ii-2 distillation tower 54. When the liquid level at the bottom of the ii-2 distillation tower 54 reaches the specified value, the CF4 electric heater 47 is turned on, and the evaporation power is slowly increased to the rated value. After 0.5 months of distillation, a concentration gradient is established in the ii-2 distillation tower 54, and the exhaust gas from the top of the ii-2 distillation tower 54 is stored in the CF4 storage tank 58 for further use. The ii-2 discharge stop valve P65 is slowly opened, and the bottom product of the ii-2 distillation tower 52 is reheated and vaporized by the heated nitrogen P before entering the ii-t distillation tower 56.

[0085] Furthermore, the condenser 57 of the ⅱ-t distillation tower condenses the CF4 gas and accumulates at the bottom of the ⅱ-t distillation tower 56. When the liquid level at the bottom of the ⅱ-t distillation tower 56 reaches the specified value, the CF4 electric heater 47 is turned on and the evaporation power is slowly increased to the rated value. After 0.2 months of distillation, the concentration gradient is established in the ⅱ-t distillation tower 56. The exhaust gas at the top of the ⅱ-t distillation tower 56 is stored in the CF4 storage tank 58 for other uses. The bottom of the ⅱ-t distillation tower 56 obtains high abundance 13 CF4 products (product abundance ( 13 C) ≥92%).

[0086] It should be pointed out that 13 The first S stage cascade of the CF4 distillation enrichment subsystem uses structured packing, and the last T stage cascade uses random packing. The use of structured packing in the first S stage can remove a large amount of impurities. 12 CF4, large quantities and rapid production of crude 13 CF4 gas; random packing is used in the last stage to achieve high efficiency concentration 13 CF4, improve product 13 CF4 yield.

[0087] It should also be noted that part of the cold nitrogen gas at the outlet of the reheating heat exchanger 42 (P, 5-7% of the total amount) is heated by the environment and then used as 13 The CF4 distillation tower bottom liquid heating gas is used to vaporize the tower bottom liquid. After heating the tower bottom liquid, it returns to the outlet of the reheating heat exchanger 42. When the cold nitrogen at the outlet of the reheating heat exchanger 42 cannot provide enough cooling capacity to 13 When the CF4 distillation and enrichment subsystem is in operation, air separation nitrogen can be added to the outlet of the rewarming heat exchanger 42.

[0088] The present invention 13 C. 18 O stable isotope co-production technology and equipment, using 18 The boiling point of O2 (89.94K, 1 bar) is lower than 13 CF4 (145.3K, 1 bar), 18 The cold nitrogen produced by the distillation enrichment of O stable isotopes is used as 13 C stable isotope distillation enrichment cold source, to achieve 13 C and 18 Highly efficient co-production of O stable isotopes, specifically: ① 18 The O2 enrichment submodule uses atmospheric pressure and low temperature distillation to continuously accumulate the rich O2 at the bottom of the distillation tower. 18 O liquid oxygen, achieved by connecting the front and rear stages in series 18 O liquid oxygen enrichment; ② 18 The O2 enrichment submodule cascade adopts the front-to-back series mode. The upper section of each distillation tower is composed of parallel tubes, and the lower section is composed of parallel tubes. The number of parallel tubes in the upper and lower sections is inconsistent, that is, the number of upper distillation tower sections is more than that of lower distillation tower sections, and the ratio of the number of upper and lower tower sections is x / y (Value range: 2:1~4:1);③ 18 The cooling source of the O2 distillation and enrichment submodule is liquid nitrogen (80K, 1 bar), and the cold nitrogen is evaporated to 13 CF4 distillation enrichment submodule;④ 18 The cold nitrogen in the O2 distillation and enrichment module enters after being reheated (reheated to 110K) 13 CF4 distillation enrichment submodule, as 13 CF4 distillation enriches the cold source and cools the CF4 gas at the top of the distillation tower. After reheating, the cold nitrogen part is heated to 200K by the environment and then purged 13 CF4 distillation enrichment module bottom liquid outlet pipe, vaporization 13 CF4 liquid, used as the raw material for the next stage of distillation; ⑤ 13 The CF4 enrichment submodule cascade adopts the front-end and back-end series mode. Each distillation tower is composed of parallel tubes. The number of parallel tubes in the front-end and back-end distillation towers is different. The number of parallel tubes in the front-end distillation tower is more than that in the back-end distillation tower. The ratio of the number of parallel tubes in the front-end and back-end distillation towers is u / v (Value range: 1:1 to 5:1).

Claims

1. A dual stable isotope co-production device, the device consists of 18 O-enriched submodule and 13 C enrichment submodule, characterized by: described 18 The raw gas of the O enrichment submodule comes from air separation oxygen and is purified by the oxygen purification device (1). The volume purity of the raw oxygen reaches 5n. The outlet of the oxygen purification device (1) is connected to the inlet of the intermediate evaporator (3) of the Ⅰ-1 distillation tower. The intermediate evaporator (3) of the Ⅰ-1 distillation tower is connected to the bottom of the upper tower section (2) of the Ⅰ-1 distillation tower and the top of the lower tower section (4) of the Ⅰ-1 distillation tower respectively. The top of the upper tower section (1) of the Ⅰ-1 distillation tower is connected to the bottom of the condenser (5) of the Ⅰ-1 distillation tower. The bottom of the lower tower section (4) of the Ⅰ-1 distillation tower is connected to the inlet of the Ⅰ-1 discharge stop valve A (26) and the inlet of the Ⅰ-1 liquid discharge stop valve F (31). The outlet of the Ⅰ-1 discharge stop valve A (26) is connected to the inlet of the intermediate evaporator (8) of the Ⅰ-2 distillation tower. The intermediate evaporator (8) of the Ⅰ-2 distillation tower is connected to the bottom of the upper tower section (7) of the Ⅰ-2 distillation tower and the top of the lower tower section (9) of the Ⅰ-2 distillation tower respectively. The top of the upper tower section (7) of the Ⅰ-2 distillation tower is connected to the bottom of the condenser (10) of the Ⅰ-2 distillation tower. The bottom of the lower tower section (9) of the Ⅰ-2 distillation tower is commonly connected to the inlet of the Ⅰ-2 discharge stop valve B (27), the inlet of the Ⅰ-2 drainage stop valve G (32), and the outlet of the Ⅰ-1 drainage stop valve F (31). The outlet of the Ⅰ-2 discharge stop valve B (27) is connected to the inlet of the intermediate evaporator of the next-stage distillation tower. The outlet of the Ⅰ-2 drainage stop valve G (32) is connected to the bottom of the next-stage distillation tower, the inlet of the bottom discharge valve of the next-stage distillation tower, and the inlet of the bottom drainage valve of the next-stage distillation tower.

2. The dual stable isotope co-generation device according to claim 1, characterized in that: The I-2 discharge stop valve B (27) is connected to the inlet of the intermediate evaporator of the next stage distillation tower. The intermediate evaporator (12) of the I-n distillation tower is connected to the bottom of the upper tower section (11) of the I-n distillation tower and the top of the lower tower section (13) of the I-n distillation tower respectively. The top of the upper tower section (11) of the I-n distillation tower is connected to the bottom of the condenser (14) of the I-n distillation tower. The bottom of the lower tower section (13) of the I-n distillation tower is connected to the inlet of the I-n discharge stop valve (28), the inlet of the I-n drain stop valve (33), and the upper stage distillation tower. The outlet of the bottom discharge stop valve is connected to the outlet of the Ⅰ-n discharge stop valve (28) and the outlet of the Ⅱ-1 distillation tower intermediate evaporator (16). The upper and lower evaporators (16) of the Ⅱ-1 distillation tower are connected to the bottom of the upper tower section (15) of the Ⅱ-1 distillation tower and the top of the lower tower section (17) of the Ⅱ-1 distillation tower respectively. The bottom of the lower tower section (17) of the Ⅱ-1 distillation tower is connected to the inlet of the Ⅱ-1 discharge stop valve D (29), the inlet of the Ⅱ-1 discharge stop valve (34) and the outlet of the Ⅰ-n distillation tower bottom discharge stop valve (33). The top of the upper tower section (15) of the distillation tower is connected to the bottom of the condenser (18) of the II-1 distillation tower, the outlet of the II-1 discharge stop valve D (29) is connected to the inlet of the intermediate evaporator (20) of the II-2 distillation tower, the upper and lower evaporators (20) of the II-2 distillation tower are respectively connected to the bottom of the upper tower section (19) of the II-2 distillation tower and the top of the lower tower section (21) of the II-2 distillation tower, and the bottom of the lower tower section (21) of the II-2 distillation tower is commonly connected to the inlet of the II-2 discharge stop valve E (30), the inlet of the II-2 drain stop valve J (35), and the inlet of the II-1 The outlet of the drain stop valve I (34) at the bottom of the distillation tower and the outlet of the drain stop valve II-2 (35) are safely emptied. The top of the upper tower section (19) of the II-2 distillation tower is connected to the bottom of the condenser (22) of the II-2 distillation tower. The outlet of the II-2 discharge stop valve (30) is connected to the inlet of the intermediate evaporator of the next-stage distillation tower. The feed port of the product concentration tower (23) is connected to the outlet of the discharge stop valve of the previous-stage distillation tower. The outlet of the product concentration tower (23) is connected to the middle feed port of the product purification tower (24). The upper discharge port of the product purification tower (24) is connected to the outlet of the product purification tower (24). 18 The top of the O2 product, the product concentration tower (23), and the top of the product purification tower (24) are connected to the bottom of the II-m distillation tower condenser (25).

3. The dual stable isotope co-production device according to claim 2, characterized in that: The exhaust port of the Ⅰ-1 distillation tower condenser (5), the exhaust port of the Ⅰ-2 distillation tower condenser (10), the exhaust port of the Ⅰ-n distillation tower condenser (14), the exhaust port of the Ⅱ-1 distillation tower condenser (18), the exhaust port of the Ⅱ-2 distillation tower condenser (22), the exhaust port of the Ⅱ-m distillation tower condenser (25), and the exhaust ports of other omitted distillation tower condensers are connected to the inlet of the waste gas storage tank (60), and the outlet of the waste gas storage tank (60) is connected to the inlet of the check valve (36). The check valve ( The outlet of the booster valve (36) is connected to the inlet of the booster valve (37), and the outlet of the booster valve (37) is connected to the air separation (ASP). Oxygen electric heaters are provided at the bottom of the lower tower section (9) of the Ⅰ-1 distillation tower, the bottom of the lower tower section (9) of the Ⅰ-2 distillation tower, the bottom of the lower tower section (13) of the Ⅰ-n distillation tower, the bottom of the lower tower section (17) of the Ⅱ-1 distillation tower, the bottom of the lower tower section (21) of the Ⅱ-2 distillation tower, and the bottom of the lower tower sections of other omitted distillation towers, the bottom of the product concentration tower (23), and the bottom of the product purification tower (24).

4. The dual stable isotope co-generation device according to claim 3, characterized in that: The cold nitrogen outlet of the Ⅰ-1 distillation tower condenser (5), the cold nitrogen outlet of the Ⅰ-2 distillation tower condenser (10), the cold nitrogen outlet of the Ⅰ-n distillation tower condenser (14), the cold nitrogen outlet of the Ⅱ-1 distillation tower condenser (18), the cold nitrogen outlet of the Ⅱ-2 distillation tower condenser (22), the cold nitrogen outlet of the Ⅱ-m distillation tower condenser (25), and the cold nitrogen outlets of the other omitted distillation tower condensers are connected to the inlet of the nitrogen stop valve (41). The outlet of the nitrogen stop valve (41) is connected to the inlet of the reheating heat exchanger (42). The nitrogen at the outlet of the reheating heat exchanger (42) is divided into two streams: ① as a heat source (P), purging and vaporizing 13 CF4 enrichment distillation tower bottom liquid, vaporization 13 CF4 is used as the raw material for the next stage of distillation; ② directly enters 13 CF4 enrichment distillation condenser, as a cold source, needs to pay attention to the following: ① Nitrogen vaporization 13 CF4 then merges with ②; the liquid nitrogen inlet of the Ⅰ-1 distillation tower condenser (5), the liquid nitrogen inlet of the Ⅰ-2 distillation tower condenser (10), the liquid nitrogen inlet of the Ⅰ-n distillation tower condenser (14), the liquid nitrogen inlet of the Ⅱ-1 distillation tower condenser (18), the liquid nitrogen inlet of the Ⅱ-2 distillation tower condenser (22), the liquid nitrogen inlet of the Ⅱ-m distillation tower condenser (25), and the liquid nitrogen inlets of the other omitted distillation tower condensers are connected to the outlet of the liquid nitrogen pump (39), the inlet of the liquid nitrogen pump (39) is connected to the outlet of the liquid nitrogen tank (38), the inlet of the liquid nitrogen tank (38) is connected to the outlet of the liquid nitrogen stop valve P (65), and the inlet of the liquid nitrogen stop valve P (65) is connected to the air separation (ASP) liquid nitrogen.

5. The dual stable isotope co-production device according to claim 1, characterized in that: described 13 The raw material of the C enrichment submodule comes from high-purity CF4 cylinder gas, which enters the adsorption purification device (43) 13 The CF4 distillation submodule, the outlet of the adsorption purification device (43) is connected to the inlet of the CF4 feed stop valve (44), the outlet of the CF4 feed stop valve (44) is connected to the feed port of the i-1 distillation tower (45), the top of the i-1 distillation tower (45) is connected to the bottom of the i-1 distillation tower condenser (46), the bottom of the i-1 distillation tower (45) is connected to the inlet of the i-1 discharge stop valve (61), the outlet of the i-1 discharge stop valve (61) is connected to the feed port of the i-2 distillation tower (66), the top of the i-2 distillation tower (66) is connected to the bottom of the i-2 distillation tower condenser (49), the bottom of the i-2 distillation tower (66) is connected to the inlet of the i-2 discharge stop valve (62), and the outlet of the i-2 discharge stop valve (62) is connected to the next level 13 CF4 distillation tower feed port, is distillation tower (50) feed port connected to the previous level 13 The outlet of the CF4 distillation tower discharge stop valve, the top of the is distillation tower (50) is connected to the bottom of the is distillation tower condenser (51), the bottom of the is distillation tower (50) is connected to the inlet of the is discharge stop valve (63), and the outlet of the is discharge stop valve (63) is connected to the feed inlet of the ⅱ-1 distillation tower (52).

6. The dual stable isotope co-production device according to claim 5, characterized in that: The top of the ⅱ-1 distillation tower (52) is connected to the bottom of the ⅱ-1 distillation tower condenser (53), the bottom of the ⅱ-1 distillation tower (52) is connected to the inlet of the ⅱ-1 discharge stop valve (64), the outlet of the ⅱ-1 discharge stop valve (64) is connected to the feed port of the ⅱ-2 distillation tower, the top of the ⅱ-2 distillation tower (54) is connected to the bottom of the ⅱ-2 distillation tower condenser (55), the bottom of the ⅱ-2 distillation tower (54) is connected to the inlet of the ⅱ-2 discharge stop valve (P65), and the outlet of the ⅱ-2 discharge stop valve (65) is connected to the next level 13 The feed port of CF4 distillation tower and the feed port of ⅱ-t concentration tower (56) are connected to the previous stage 13 The outlet of the CF4 distillation tower discharge stop valve, the top of the ⅱ-t concentration tower (56) is connected to the bottom of the ⅱ-t distillation tower condenser (57), and the bottom of the ⅱ-t distillation tower (56) is connected to the outlet of the CF4 distillation tower discharge stop valve. 13 Product C.

7. The dual stable isotope co-production device according to claim 6, characterized in that: The nitrogen inlet of the i-1 rectifying tower condenser (46), the nitrogen inlet of the i-2 rectifying tower condenser (49), the nitrogen inlet of the is rectifying tower condenser (51), the nitrogen inlet of the ⅱ-1 rectifying tower condenser (53), the nitrogen inlet of the ⅱ-2 rectifying tower condenser (55), the nitrogen inlet of the ⅱ-t rectifying tower condenser (57), and the nitrogen inlets of other omitted rectifying tower condensers are connected together to the outlet of the reheating heat exchanger (42), the nitrogen outlet of the i-1 rectifying tower condenser (46), the nitrogen outlet of the i-2 rectifying tower condenser (49), the nitrogen outlet of the is rectifying tower condenser (51), the nitrogen outlet of the ⅱ-1 rectifying tower condenser (53), the nitrogen outlet of the ⅱ-2 rectifying tower condenser (55), the nitrogen outlet of the ⅱ-t rectifying tower condenser (57), and the nitrogen outlet of other omitted rectifying tower condensers. The nitrogen reflux valve (59) inlet is commonly connected, and the nitrogen reflux valve (59) outlet is connected to the air separation (ASP) nitrogen inlet, the i-1 distillation tower condenser (46) exhaust port, the i-2 distillation tower condenser (49) exhaust port, the is distillation tower condenser (51) exhaust port, the ⅱ-1 distillation tower condenser (53) exhaust port, the ⅱ-2 distillation tower condenser (55) exhaust port, the ⅱ-2 distillation tower condenser (57) exhaust port, and the exhaust ports of other omitted distillation tower condensers are commonly connected to the CF4 storage tank (58), the i-1 distillation tower (45), the i-2 distillation tower (66), the is distillation tower (50), the ⅱ-1 distillation tower (52), the ⅱ-2 distillation tower (54), the ⅱ-t distillation tower (56), and the other omitted distillation towers, and a CF4 electric heater (47) is provided at the bottom.

8. The method for using the dual stable isotope co-production device according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: 1) Before starting the system, vacuum is required. Open the discharge stop valve (26) to the discharge stop valve E30), the boost valve (37), the discharge stop valve (61) to the discharge stop valve (65), and the nitrogen stop valve (41). Close the drain stop valve (31) to the drain stop valve (35). The system material pipeline is vacuumed to less than 10 Pa and all valves are closed. Before starting the system, the entire device must be pre-cooled. Slowly open the liquid nitrogen stop valve P (65) to allow the atmospheric pressure liquid nitrogen of the air separation to enter the liquid nitrogen tank (38). After the liquid level of the liquid nitrogen tank (38) reaches the specified value, start the liquid nitrogen pump (39), Ⅰ-1 distillation tower condenser (5), Ⅰ-2 distillation tower condenser (10), Ⅰ-n distillation tower condenser (14), Ⅱ-1 distillation tower condenser (18), Ⅱ-2 distillation tower condenser (22), Ⅱ-m distillation tower condenser (25), and other He omitted the distillation tower condenser, and at the same time, liquid nitrogen was introduced, and the device began to cool down. When the temperature value displayed by the system temperature measuring point dropped to the set value, the air separation raw material oxygen was purified by the oxygen purification device (1) and entered the intermediate evaporator (3) of the Ⅰ-1 distillation tower. It was condensed by the condenser (5) of the Ⅰ-1 distillation tower and accumulated at the bottom of the lower tower section (4) of the Ⅰ-1 distillation tower. When the accumulated liquid in the lower tower section (4) of the Ⅰ-1 distillation tower submerged the entire lower tower section (4) of the Ⅰ-1 distillation tower, the oxygen electric heater (6) was turned on, and the evaporation power was slowly increased to the rated value. After 2.5 months of distillation, a concentration gradient was established between the upper tower section (2) of the Ⅰ-1 distillation tower and the lower tower section (4) of the Ⅰ-1 distillation tower. At this time, the booster valve (37) was slowly opened, and the exhaust gas at the top of the upper tower section (2) of the Ⅰ-1 distillation tower passed through the exhaust gas storage tank (60), the check valve (36), and the booster valve (37) and returned to the air separation device (40). 2) Open the I-1 discharge stop valve (26), the bottom product of the lower section (4) of the I-1 distillation tower is discharged from the cold box for reheating and vaporization, and then enters the intermediate evaporator (8) of the I-2 distillation tower. The oxygen in the tower is liquefied by the condenser (10) of the I-2 distillation tower and accumulated at the bottom of the lower section (9) of the I-2 distillation tower. When the liquid in the lower section (9) of the I-2 distillation tower submerges the entire lower section (9) of the I-2 distillation tower, turn on the oxygen electric heater (6) and slowly increase the evaporation power to the rated value. After 1.5 months of distillation, a concentration gradient is established between the upper section (7) of the I-2 distillation tower and the lower section (9) of the I-2 distillation tower. The waste gas at the top of the upper section (2) of the I-2 distillation tower passes through the waste gas storage tank (60), the check valve (36) and the booster valve (37) and returns to the air separation unit (40); 3) Open the I-2 discharge stop valve (27), and the bottom product of the lower tower section (9) of the I-2 distillation tower is discharged from the cold box for reheating and vaporization, and then enters the next level distillation tower. It is worth noting that in the device of the present invention, 18 The O enrichment submodule is divided into a structured packing system and a random packing system. The structured packing system is cascaded to Ⅰ-1, Ⅰ-2, ..., Ⅰ-n, with a total of n stages; the random packing system is cascaded to Ⅱ-1, Ⅱ-2, ..., Ⅱ-m, with a total of m stages. The operation process of each cascade tower of the structured packing system is the same as that of the Ⅰ-1 distillation tower and the Ⅰ-2 distillation tower. 4) The feed to the intermediate evaporator (12) of the Ⅰ-n distillation tower is from the outlet of the discharge stop valve at the bottom of the lower section of the upper distillation tower. The condenser (14) of the Ⅰ-n distillation tower liquefies the oxygen in the tower and accumulates it at the bottom of the lower section (13) of the Ⅰ-n distillation tower. When the liquid in the lower section (13) of the Ⅰ-n distillation tower submerges the entire lower section (13) of the Ⅰ-n distillation tower, the oxygen electric heater (6) is turned on and the evaporation power is slowly increased to the rated value. After one month of distillation, a concentration gradient is established between the upper section (11) of the Ⅰ-n distillation tower and the lower section (13) of the Ⅰ-n distillation tower. The exhaust gas at the top of the upper section (11) of the Ⅰ-n distillation tower returns to the air separation unit (40) through the exhaust gas storage tank (60), the check valve (36) and the booster valve (37). 5) Open the I-n discharge stop valve (28), and the bottom product of the lower tower section (13) of the I-n distillation tower is discharged from the cold box for reheating and vaporization, and then enters the random packing system (II-1, II-2, ..., II-m); 6) First, the bottom product of the lower section (13) of the Ⅰ-n distillation tower is reheated and vaporized after leaving the cold box, and enters the intermediate evaporator (16) of the Ⅱ-1 distillation tower. The oxygen in the tower is liquefied by the condenser (18) of the Ⅱ-1 distillation tower and accumulates at the bottom of the lower section (17) of the Ⅱ-1 distillation tower. When the accumulated liquid in the lower section (17) of the Ⅱ-1 distillation tower immerses the entire lower section (17) of the Ⅱ-1 distillation tower, the oxygen electric heater (6) is turned on, and the evaporation power is slowly increased to the rated value. After 0.8 months of distillation, a concentration gradient is established between the upper section (15) of the Ⅱ-1 distillation tower and the lower section (17) of the Ⅱ-1 distillation tower. The waste gas at the top of the upper section (15) of the Ⅱ-1 distillation tower passes through the waste gas storage tank (60), the check valve (36), and the booster valve (37) and returns to the air separation unit (40); 7) Open the II-1 discharge stop valve D (29), the bottom product of the II-1 distillation tower lower section (17) is discharged from the cold box for reheating and vaporization, and enters the II-2 distillation tower intermediate evaporator (20), the II-2 distillation tower condenser (22) liquefies the oxygen in the tower, and accumulates at the bottom of the II-2 distillation tower lower section (21). When the liquid in the II-2 distillation tower lower section (21) submerges the entire II-2 distillation tower lower section (21), turn on the oxygen electric heater (6), and slowly increase the evaporation power to the rated value. After 0.6 months of distillation, a concentration gradient is established between the II-2 distillation tower upper section (19) and the II-2 distillation tower lower section (21). The waste gas at the top of the II-2 distillation tower upper section (19) returns to the air separation unit (40) through the waste gas storage tank (60), the check valve (36), and the boost valve (37); 8) Open the II-2 discharge stop valve E30), the bottom product of the lower tower section (21) of the II-2 distillation tower is discharged from the cold box for reheating and vaporization, and then sent to the next distillation tower. It is worth noting that in the device of the present invention, the random packing system is cascaded to II-1, II-2, ..., I-m, with a total of m stages. The operation process of each stage of the random packing system cascade tower is consistent with that of the II-1 distillation tower and the II-2 distillation tower; 9) The raw material of the product concentration tower (23) comes from the outlet of the discharge stop valve at the bottom of the lower tower section of the upper distillation tower. The condenser (25) of the II-m distillation tower liquefies the oxygen in the product concentration tower (23) and accumulates at the bottom of the product concentration tower (23). When the liquid accumulation height at the bottom of the product concentration tower (23) reaches the set value, the oxygen electric heater (6) is turned on and the evaporation power is slowly increased to the rated value. After 0.3 months of distillation, a concentration gradient is established in the product concentration tower (23). The exhaust gas at the top of the product concentration tower (23) is returned to the air separation unit (40) through the exhaust gas storage tank (60), the check valve (36) and the boost valve (37); 10) The liquid at the bottom of the product concentration tower (23) has reached the product isotope abundance requirement. To further improve the chemical purity of the product, the content of heavy component impurities is reduced to below 0.1ppm. The gas at the bottom of the product concentration tower (23) is introduced into the upper part of the product purification tower (24). The oxygen in the product purification tower (24) is liquefied by the condenser (25) of the II-m distillation tower and accumulated at the bottom of the product purification tower (24). When the liquid accumulation height at the bottom of the product purification tower (24) reaches the set value, the oxygen electric heater (6) is turned on and the evaporation power is slowly increased to the rated value. The distillation is continued for 32 hours. The top of the product purification tower (24) is heated to 1000 ℃. 18 The heavy component impurities of the O isotope product were reduced to below 0.1ppm. It is important to note that in the distillation cascades II-1, II-2, ..., and II-m, the upper tower section uses structured packing, while the lower tower section uses random packing. The use of structured packing in the upper tower section can increase the evaporation steam volume of each cascade stage, thereby providing more raw liquid for the lower tower section; the use of random packing in the lower tower section can effectively reduce HETP and increase the number of theoretical plates, thereby improving the cascade enrichment efficiency. 11) 18 During the operation of the O2 distillation and enrichment submodule, the cold nitrogen generated by the Ⅰ-1 distillation tower condenser (5), Ⅰ-2 distillation tower condenser (10), Ⅰ-n distillation tower condenser (14), Ⅱ-1 distillation tower condenser (18), Ⅱ-2 distillation tower condenser (22), Ⅱ-m distillation tower condenser (25), and other omitted distillation tower condensers can be used as 13 CF4 distillation and enrichment submodule cold source; 12) The device starts in the order of priority 18 O distillation enrichment subsystem, after 13 CF4 distillation enrichment subsystem, open the nitrogen reflux valve (59), 18 The cold nitrogen discharged during the startup of the O distillation and enrichment subsystem and the distillation balance process can be pre-cooled through the process pipeline 13 CF4 distillation enrichment subsystem, when 13 The temperature measurement point display value of the CF4 distillation and enrichment subsystem is reduced to the set value, the process pipeline is closed, and the nitrogen stop valve (41) is slowly opened. The cold nitrogen generated by the Ⅰ-1 distillation tower condenser (5), Ⅰ-2 distillation tower condenser (10), Ⅰ-n distillation tower condenser (14), Ⅱ-1 distillation tower condenser (18), Ⅱ-2 distillation tower condenser (22), Ⅱ-m distillation tower condenser (25), and other omitted distillation tower condensers enters the reheating heat exchanger (42), and the cold nitrogen is reheated to 100K; 13) After reheating, the cold nitrogen (100K) enters the i-1 distillation tower condenser (46), the i-2 distillation tower condenser (49), the is distillation tower condenser (51), the ⅱ-1 distillation tower condenser (53), the ⅱ-2 distillation tower condenser (55), the ⅱ-t distillation tower condenser (57), and other omitted distillation tower condensers, and the CF4 feed stop valve (44) is slowly opened. High-purity CF4 (V / V≥99.999%) is purified by the adsorption purification device (43) to a purity of 7n, and then enters the i-1 distillation tower (45). The i-1 distillation tower condenser ( 46) Condensing CF4 gas, liquid CF4 accumulates at the bottom of the i-1 distillation tower (45). When the liquid level at the bottom of the i-1 distillation tower (45) reaches the specified value, the CF4 electric heater (47) is turned on, and the evaporation power is slowly increased to the rated value. After 2.2 months of distillation, a concentration gradient is established in the i-1 distillation tower (45). The waste gas at the top of the i-1 distillation tower (45) is stored in the CF4 storage tank (58) for other uses. The i-1 discharge stop valve (61) is slowly opened, and the bottom product of the i-1 distillation tower (45) is vaporized by the heated nitrogen (P) and then enters the i-2 distillation tower (66). 14) The condenser (49) of the i-2 distillation tower condenses CF4 gas, and liquid CF4 accumulates at the bottom of the i-2 distillation tower (66). When the liquid level at the bottom of the i-2 distillation tower (66) reaches the specified value, the CF4 electric heater (47) is turned on, and the evaporation power is slowly increased to the rated value. After 1.5 months of distillation, a concentration gradient is established in the i-2 distillation tower (66). The exhaust gas at the top of the i-2 distillation tower (66) is stored in the CF4 storage tank (58) for other uses. The i-2 discharge stop valve (62) is slowly opened, and the bottom product of the i-2 distillation tower (66) is vaporized by the heated nitrogen (P) and then enters the next distillation tower. It should be noted that 13 The CF4 distillation enrichment subsystem is set up with (s+t) stages of cascade, namely i-1, i-2, ..., is, ⅱ-1, ⅱ-2, ..., ⅱ-t. The operation process of each cascade tower is the same as that of the i-1 distillation tower and the i-2 distillation tower; 15) The feed gas of the is distillation tower (50) comes from the outlet of the bottom discharge stop valve of the upper cascade tower. The condenser (51) of the is distillation tower condenses CF4 gas and accumulates at the bottom of the is distillation tower (50). When the liquid level at the bottom of the is distillation tower (50) reaches the specified value, the CF4 electric heater (47) is turned on and the evaporation power is slowly increased to the rated value. After distillation for 1 month, the concentration gradient of the is distillation tower (50) is established. The waste gas at the top of the is distillation tower (50) is stored in the CF4 storage tank (58) for other use. The is discharge stop valve (63) is slowly opened. The bottom product of the is distillation tower (50) is vaporized by heating nitrogen (P) and then enters the ⅱ-1 distillation tower (52); 16) The condenser (53) of the ⅱ-1 distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-1 distillation tower (52). When the liquid level at the bottom of the ⅱ-1 distillation tower (52) reaches the specified value, the CF4 electric heater (47) is turned on and the evaporation power is slowly increased to the rated value. After 0.7 months of distillation, a concentration gradient is established in the ⅱ-1 distillation tower (52). The exhaust gas at the top of the ⅱ-1 distillation tower (52) is stored in the CF4 storage tank (58) for other uses. The ⅱ-1 discharge stop valve (64) is slowly opened, and the bottom product of the ⅱ-1 distillation tower (52) is vaporized by reheating with heated nitrogen (P) and then enters the ⅱ-2 distillation tower (54); 17) The condenser (55) of the ⅱ-2 distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-2 distillation tower (54). When the liquid level at the bottom of the ⅱ-2 distillation tower (54) reaches the specified value, the CF4 electric heater (47) is turned on and the evaporation power is slowly increased to the rated value. After 0.5 months of distillation, a concentration gradient is established in the ⅱ-2 distillation tower (54). The exhaust gas at the top of the ⅱ-2 distillation tower (54) is stored in the CF4 storage tank (58) for other uses. The ⅱ-2 discharge stop valve (65) is slowly opened, and the bottom product of the ⅱ-2 distillation tower (52) is vaporized by reheating with heated nitrogen (P) and then enters the ⅱ-t distillation tower (56); 18) The condenser (57) of the ⅱ-t distillation tower condenses CF4 gas and accumulates at the bottom of the ⅱ-t distillation tower (56). When the liquid level at the bottom of the ⅱ-t distillation tower (56) reaches the specified value, the CF4 electric heater (47) is turned on and the evaporation power is slowly increased to the rated value. After 0.2 months of distillation, a concentration gradient is established in the ⅱ-t distillation tower (56). The exhaust gas at the top of the ⅱ-t distillation tower (56) is stored in the CF4 storage tank (58) for other uses. The bottom of the ⅱ-t distillation tower (56) is provided with high abundance. 13 CF4 products.

9. The method for using the dual stable isotope co-production device according to claim 8, characterized in that: described 13 The first S stage cascade of the CF4 distillation enrichment subsystem uses structured packing, and the last T stage cascade uses random packing. The first S stage uses structured packing to remove a large amount of impurities. 12 CF4, large quantities and rapid production of crude 13 CF4 gas; random packing is used in the last stage to achieve high efficiency concentration 13 CF4, improve product 13 CF4 yield.

10. The method for using the dual stable isotope co-production device according to claim 8, characterized in that: Part of the cold nitrogen at the outlet of the reheating heat exchanger (42) is heated by the environment and then used as 13 The CF4 distillation tower bottom liquid heating gas is used to vaporize the tower bottom liquid, heat the tower bottom liquid and return to the outlet of the reheating heat exchanger (42). When the cold nitrogen at the outlet of the reheating heat exchanger (42) cannot provide enough cooling capacity to 13 When the CF4 distillation enrichment subsystem is in operation, air separation nitrogen can be added to the outlet of the rewarming heat exchanger (42).

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