Low-energy-consumption stable isotope carbon-13 concentration method

Abstract

The invention belongs to the technical field of stable isotope concentration, and particularly discloses a low-energy-consumption stable isotope carbon-13 concentration method. The method comprises the following steps: performing impurity removal treatment on a raw material CO gas to obtain a high-purity CO gas; then the high-purity CO gas is rectified, and rectified CO gas is obtained; and adsorbing the rectified CO gas by adopting an adsorption material, and after the adsorption is completed, analyzing to obtain the concentrated stable isotope carbon-13. According to the method, the influence of impurity gas on the abundance of the carbon isotope can be avoided to the greatest extent through impurity removal treatment, and the abundance of the stable isotope carbon-13 is improved; in the rectification process, a condenser is only arranged at the top of the first-stage rectification tower, so that the application of equipment is reduced, the energy consumption required by the reaction is greatly reduced, and the obtained stable isotope carbon-13 has higher abundance by matching with an adsorption material for adsorption treatment.

Description

Technical Field

[0001] The invention relates to the technical field of stable isotope enrichment, and in particular to a method for enriching stable isotope carbon-13 with low energy consumption. Background Art

[0002] Stable isotopes are those that are not susceptible to radioactive decay. In nature, these isotopes exist in fixed proportions, and the number of protons and neutrons in their nuclei makes them more stable than other isotopes. Stable isotopes include 13 C. 18 O. 15 N. 10 B. Stable isotopes play an irreplaceable role in many fields such as scientific research, medical diagnosis, environmental monitoring and industrial applications due to their stable properties.

[0003] Among the various stable isotopes, the most widely used are 13 C, therefore, 13 The concentrated preparation of C is a research focus in this field. 13 There are many methods for separating C, such as thermal diffusion, gas diffusion, centrifugal separation, laser, chemical exchange, ion exchange and distillation. Among them, the distillation method is mainly low-temperature distillation, which uses the slight difference in boiling points between isotope molecules to separate light and heavy components through multiple vapor-liquid phase exchanges in a distillation tower under low temperature conditions. 13 The C concentration and separation process needs to be carried out at extremely low temperatures, with low separation coefficients, high theoretical plate numbers, small flow rates, thin and long distillation towers, long equilibrium times, and great difficulty in equipment manufacturing and installation. Although cryogenic distillation has the ability to efficiently separate isotopes, its technical difficulty and energy consumption are also relatively high.

[0004] Therefore, how to provide a low-energy-consumption stable isotope carbon-13 enrichment method, improve the separation coefficient, obtain a higher abundance of carbon-13 isotopes, and reduce energy consumption is a difficult problem to be solved in this field. Summary of the invention

[0005] In view of this, the present invention provides a low-energy-consumption method for concentrating the stable isotope carbon-13 to solve the problems of high energy consumption and low separation coefficient in the existing concentration and separation methods.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for concentrating stable isotope carbon-13 with low energy consumption comprises the following steps:

[0008] 1) The raw CO gas is subjected to impurity removal treatment to obtain high-purity CO gas;

[0009] 2) distilling the high-purity CO gas to obtain distilled CO gas;

[0010] 3) The CO gas after distillation is adsorbed by an adsorption material. After the adsorption is completed, the concentrated stable isotope carbon-13 is obtained by analysis.

[0011] Preferably, the distillation is carried out using 2 to 4 distillation towers with successively decreasing tower diameters;

[0012] Among them, the distillation tower is filled with corrugated packing;

[0013] High-purity CO gas enters from the middle of the first-stage distillation tower, and the top of the first-stage distillation tower is connected to the condenser through a gas phase pipeline and a liquid phase pipeline respectively;

[0014] The bottom of each distillation tower is connected to a reboiler, the bottom of the front distillation tower is connected to the top of the secondary distillation tower via a liquid phase pipeline, the light isotope gas at the top of the secondary distillation tower is connected to the bottom of the front distillation tower via a gas phase pipeline, and the medium isotope liquid in the bottom of the front distillation tower is transported to the top of the secondary distillation tower via a liquid pump;

[0015] The light isotope steam at the top of the first-stage distillation tower is discharged from the exhaust gas pipeline at the top. The bottom of the last-stage distillation tower is the liquefied CO gas after distillation, which is led out through a pipeline, and there is no gas phase returning to the bottom of the tower.

[0016] The liquid in the kettle of the previous distillation tower is transported to the top of the secondary distillation tower through a cryogenic liquid pump as the spray liquid of the secondary distillation tower; the steam at the top of the secondary distillation tower is returned to the kettle of the previous distillation tower through pressure.

[0017] Preferably, the reboiling ratio of the last distillation tower is 120-150, and the reboiling ratio of the remaining distillation towers is 1-10; the pressure in each distillation tower is 0.5-5 bar, and the gas phase kinetic energy factor is 0.5-1 m / s (kg / m 3 ) 1 / 2 .

[0018] Preferably, the diameter of each stage of the distillation tower is independently 50 to 5000 mm.

[0019] Preferably, an isotope scrambler is further provided between the first-stage distillation tower and the second-stage distillation tower.

[0020] Preferably, the impurity removal treatment in step 1) includes low-temperature impurity removal, room-temperature adsorption, heavy impurity removal, light impurity removal and secondary low-temperature impurity removal performed in sequence.

[0021] Preferably, the adsorption material in step 3) is 5A molecular sieve.

[0022] Preferably, the adsorption temperature is -100 to -150°C, and the desorption temperature is 550 to 600°C.

[0023] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention discloses a CO gas impurity removal process, which can avoid the influence of impurity gases on the carbon isotope abundance to the greatest extent and increase the abundance of the stable isotope carbon-13;

[0025] 2. The present invention only sets a condenser at the top of the first-stage distillation tower, and the other distillation towers do not need to be set with low-temperature condensers, which reduces the application of equipment and greatly reduces the energy consumption required for the reaction; in addition, the number of stages of the distillation tower used in the present invention is small, which simplifies the distillation process;

[0026] 3. The present invention uses a low-order distillation tower to carry out adsorption treatment in conjunction with adsorption materials, which greatly ensures the abundance of the stable isotope carbon-13 and avoids the decrease in separation capacity due to the reduction in the number of distillation towers. DETAILED DESCRIPTION

[0027] The present invention provides a method for concentrating stable isotope carbon-13 with low energy consumption, comprising the following steps:

[0028] 1) The raw CO gas is subjected to impurity removal treatment to obtain high-purity CO gas;

[0029] 2) distilling the high-purity CO gas to obtain distilled CO gas;

[0030] 3) The CO gas after distillation is adsorbed by an adsorption material. After the adsorption is completed, the concentrated stable isotope carbon-13 is obtained by analysis.

[0031] In the present invention, the distillation is achieved by using 2 to 4 distillation towers with successively decreasing tower diameters, specifically 2, 3, and 4.

[0032] In the present invention, the distillation tower is filled with corrugated packing.

[0033] In the present invention, high-purity CO gas enters from the middle of the first-stage distillation tower, the top of the first-stage distillation tower is connected to the condenser through a gas phase pipeline and a liquid phase pipeline respectively, and the remaining distillation towers are not provided with condensers.

[0034] In the present invention, the bottom of each stage of the distillation tower is connected to a reboiler, the bottom of the front-stage distillation tower is connected to the top of the secondary distillation tower via a liquid phase pipeline, the light isotope gas at the top of the secondary distillation tower is connected to the bottom of the front-stage distillation tower via a gas phase pipeline, and the medium isotope liquid in the bottom of the front-stage distillation tower is transported to the top of the secondary distillation tower by a liquid pump;

[0035] In the present invention, the light isotope steam at the top of the first-stage distillation tower is discharged from the waste gas pipeline at the top, and the bottom of the last-stage distillation tower is liquefied CO gas after distillation, which is led out through a pipeline, and there is no gas phase returning to the bottom of the tower.

[0036] In the present invention, the liquid in the kettle of the previous distillation tower is transported to the top of the secondary distillation tower by a cryogenic liquid pump as the spray liquid of the secondary distillation tower; the steam at the top of the secondary distillation tower is returned to the kettle of the previous distillation tower by pressure.

[0037] In the present invention, the reboiling ratio of the last distillation tower is 120-150, specifically 125, 130, 135, 140, 145; the reboiling ratios of the remaining distillation towers are 1-10, specifically 2, 3, 4, 5, 6, 7, 8, 9; the pressure in each distillation tower is 0.5-5 bar, specifically 0.8 bar, 1 bar, 1.5 bar, 2 bar, 2.5 bar, 3 bar, 3.5 bar, 4 bar, 4.5 bar; the gas phase kinetic energy factor is 0.5-1 m / s (kg / m 3 ) 1 / 2 , specifically 0.6m / s(kg / m 3 ) 1 / 2 , 0.7m / s(kg / m 3 ) 1 / 2 , 0.8m / s(kg / m 3 ) 1 / 2 , 0.9m / s(kg / m 3 ) 1 / 2 .

[0038] In the present invention, the diameter of each level of distillation tower is independently 50-5000 mm, and specifically can be 100 mm, 300 mm, 500 mm, 800 mm, 1000 mm, 2000 mm, 3000 mm, and 4000 mm.

[0039] In the present invention, an isotope scrambler is further provided between the first-stage distillation tower and the second-stage distillation tower.

[0040] In the present invention, the catalyst used in the isotope scrambler is alumina, and the operating temperature is 350-750°C, specifically 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C.

[0041] In the present invention, the impurity removal treatment in step 1) includes low-temperature impurity removal, room-temperature adsorption, heavy impurity removal, light impurity removal and secondary low-temperature impurity removal performed in sequence.

[0042] In the present invention, the adsorption material in step 3) is 5A molecular sieve.

[0043] In the present invention, the adsorption temperature is -100 to -150°C, specifically -110°C, -120°C, -130°C, -140°C; the decomposition temperature is 550 to 600°C, specifically 560°C, 570°C, 580°C, 590°C.

[0044] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] The raw CO gas is subjected to low-temperature impurity removal at 300 psia and 180K, and then introduced into a normal temperature adsorber for adsorption at 215 psia and 270K; then introduced into a de-weighting tower, the pressure is controlled to be 210 psia, the temperature is 110K, and the gas flow rate is 4.5 kg / h to carry out heavy impurity removal in the de-weighting tower to remove impurity components such as nitrogen and methane in the raw gas, and then the gas is subjected to light impurity removal in a light-weighting tower at 120 psia, 100K, and 3.5 kg / h to remove impurity components such as oxygen; the gas after light impurity removal is compressed and stored by a compressor, and then subjected to secondary low-temperature impurity removal in a low-temperature cold trap at 300 psia and 185K to complete the impurity removal step.

[0047] The impurity-free CO gas enters the distillation tower from the feed pipe in the middle of the first-stage distillation tower. The steam at the top of the first-stage distillation tower enters the condenser at the top of the tower through the gas phase pipeline. The condensed liquid returns to the top of the distillation tower as the spray liquid of the first-stage distillation tower. The distillation tower is filled with corrugated packing. The vapor and liquid phases in the tower are exchanged and distilled on the surface of the packing. The light isotope components are enriched at the top of the tower, and the heavy isotope components are enriched in the bottom of the tower. The liquid in the tower is heated and vaporized in the reboiler located in the bottom of the tower and converted into the gas phase. The reboiling ratio is 10, the pressure in the tower is 2 bar, and the gas phase kinetic energy factor is 0.8 m / s (kg / m 3 ) 1 / 2 , the tower diameter is 1500mm.

[0048] The liquid of the first-stage distillation tower passes through the liquid phase pipeline and is transported to the top of the second-stage distillation tower by a cryogenic liquid pump as the spray liquid of the second-stage distillation tower; the light isotope gas at the top of the second-stage distillation tower returns to the first-stage distillation tower through the gas phase pipeline under pressure. The light isotope steam of the first-stage distillation tower is discharged through the exhaust gas pipeline at the top. The reboiling ratio of the second-stage distillation tower is 10, the pressure in the tower is 2 bar, and the gas phase kinetic energy factor is 0.6 m / s (kg / m 3 )1 / 2 , the tower diameter is 1000mm.

[0049] The liquid output from the bottom of the second-stage distillation tower is input from the top of the third-stage distillation tower through a cryogenic liquid pump as the spray liquid of the third-stage distillation tower. The vapor and liquid phases in the tower are exchanged and distilled on the surface of the packing. The light isotope components are enriched at the top of the tower, and the heavy isotope components are enriched in the bottom of the tower. The liquid in the tower bottom is heated and vaporized by the reboiler, converted into the gas phase, and the stable isotope components are obtained. 13 The light isotope gas at the top of the third-stage distillation tower is driven by pressure and returns to the bottom of the second-stage distillation tower through the gas phase pipeline. The reboiling ratio of the third-stage distillation tower is 150, the pressure in the tower is 2 bar, and the gas phase kinetic energy factor is 0.5 m / s (kg / m 3 ) 1 / 2 The tower diameter is 400 mm. The gas at the top of the second-stage distillation tower is subjected to scrambling and reorganization treatment by an isotope scrambler before returning to the first-stage distillation tower.

[0050] Will 13 The CO intermediate product is contacted with the adsorption material 5A molecular sieve and adsorbed at -130°C. After the adsorption is completed, the temperature is increased to 580°C at a heating rate of 5°C / min for desorption to obtain a stable isotope carbon-13 product.

[0051] After testing, the abundance of carbon-13 was found to be 99.97%.

[0052] Example 2

[0053] The raw CO gas is subjected to low-temperature impurity removal at 300 psia and 180K, and then introduced into a normal temperature adsorber for adsorption at 215 psia and 270K; then introduced into a de-weighting tower, the pressure is controlled to be 210 psia, the temperature is 110K, and the gas flow rate is 4.5 kg / h to carry out heavy impurity removal in the de-weighting tower to remove impurity components such as nitrogen and methane in the raw gas, and then the gas is subjected to light impurity removal in a light-weighting tower at 120 psia, 100K, and 3.5 kg / h to remove impurity components such as oxygen; the gas after light impurity removal is compressed and stored by a compressor, and then subjected to secondary low-temperature impurity removal in a low-temperature cold trap at 300 psia and 185K to complete the impurity removal step.

[0054] The impurity-free CO gas enters the distillation tower from the feed pipe in the middle of the first-stage distillation tower. The steam at the top of the first-stage distillation tower enters the condenser at the top of the tower through the gas phase pipeline. The condensed liquid returns to the top of the distillation tower as the spray liquid of the first-stage distillation tower. The distillation tower is filled with corrugated packing. The vapor and liquid phases in the tower are exchanged and distilled on the surface of the packing. The light isotope components are enriched at the top of the tower, and the heavy isotope components are enriched in the bottom of the tower. The liquid in the tower is heated and vaporized in the reboiler located in the bottom of the tower and converted into the gas phase. The reboiling ratio is 8, the pressure in the tower is 3 bar, and the gas phase kinetic energy factor is 1 m / s (kg / m 3 ) 1 / 2 , the tower diameter is 2000mm.

[0055] The liquid from the first-stage distillation tower passes through the liquid phase pipeline and is transported to the top of the second-stage distillation tower by a cryogenic liquid pump as the spray liquid of the second-stage distillation tower; the light isotope gas at the top of the second-stage distillation tower returns to the first-stage distillation tower through the gas phase pipeline under pressure. The light isotope steam from the first-stage distillation tower is discharged through the exhaust gas pipeline at the top. The light isotope components are enriched at the top of the tower, and the heavy isotope components are enriched in the bottom of the tower. The liquid in the tower bottom is heated and vaporized by the reboiler, converted into the gas phase, and the stable isotope components are obtained. 13 CO intermediate product. The reboiling ratio of the second stage distillation tower is 140, the pressure in the tower is 5 bar, and the gas phase kinetic energy factor is 0.6 m / s (kg / m 3 ) 1 / 2 The tower diameter is 800 mm. The gas at the top of the second-stage distillation tower is subjected to scrambling and reorganization treatment by an isotope scrambler before returning to the first-stage distillation tower.

[0056] Will 13 The CO intermediate product is contacted with the adsorption material 5A molecular sieve and adsorbed at -150°C. After the adsorption is completed, the temperature is increased to 600°C at a heating rate of 5°C / min for desorption to obtain a stable isotope carbon-13 product.

[0057] After testing, the abundance of carbon-13 was found to be 99.85%.

[0058] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0059] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for concentrating the stable isotope carbon-13 with low energy consumption, characterized in that: The steps include: 1) The raw CO gas is subjected to impurity removal treatment to obtain high-purity CO gas; 2) distilling the high-purity CO gas to obtain distilled CO gas; 3) The CO gas after distillation is adsorbed by an adsorption material. After the adsorption is completed, the concentrated stable isotope carbon-13 is obtained by analysis.

2. A method for concentrating stable isotope carbon-13 with low energy consumption according to claim 1, characterized in that: The distillation is achieved by using 2 to 4 distillation towers with successively decreasing tower diameters; Among them, the distillation tower is filled with corrugated packing; High-purity CO gas enters from the middle of the first-stage distillation tower, and the top of the first-stage distillation tower is connected to the condenser through a gas phase pipeline and a liquid phase pipeline respectively; The bottom of each distillation tower is connected to a reboiler, the bottom of the front distillation tower is connected to the top of the secondary distillation tower via a liquid phase pipeline, the light isotope gas at the top of the secondary distillation tower is connected to the bottom of the front distillation tower via a gas phase pipeline, and the medium isotope liquid in the bottom of the front distillation tower is transported to the top of the secondary distillation tower via a liquid pump; The light isotope steam at the top of the first-stage distillation tower is discharged from the exhaust gas pipeline at the top. The bottom of the last-stage distillation tower is the liquefied CO gas after distillation, which is led out through a pipeline, and there is no gas phase returning to the bottom of the tower. The liquid in the kettle of the previous distillation tower is transported to the top of the secondary distillation tower through a cryogenic liquid pump as the spray liquid of the secondary distillation tower; the steam at the top of the secondary distillation tower is returned to the kettle of the previous distillation tower through pressure.

3. A method for concentrating stable isotope carbon-13 with low energy consumption according to claim 2, characterized in that: The reboiling ratio of the last distillation tower is 120-150, and the reboiling ratio of the remaining distillation towers is 1-10; the pressure in each distillation tower is 0.5-5 bar, and the gas phase kinetic energy factor is 0.5-1 m / s (kg / m 3 ) 1 / 2 .

4. The method for concentrating the stable isotope carbon-13 with low energy consumption according to claim 3, characterized in that: The diameter of each level of distillation tower is independently 50 to 5000 mm.

5. A method for concentrating stable isotope carbon-13 with low energy consumption according to claim 4, characterized in that: An isotope scrambler is also included between the first-stage distillation tower and the second-stage distillation tower.

6. A method for concentrating stable isotope carbon-13 with low energy consumption according to any one of claims 1 to 5, characterized in that: The impurity removal treatment in step 1) includes low-temperature impurity removal, room-temperature adsorption, heavy impurity removal, light impurity removal and secondary low-temperature impurity removal performed in sequence.

7. A method for concentrating stable isotope carbon-13 with low energy consumption according to claim 6, characterized in that: The adsorption material in step 3) is 5A molecular sieve.

8. The method for concentrating the stable isotope carbon-13 with low energy consumption according to claim 7, characterized in that: The adsorption temperature is -100 to -150°C, and the desorption temperature is 550 to 600°C.