CO low-temperature rectification process capable of separating rectification section from stripping section

Abstract

The invention belongs to the technical field of separation and purification of substances, and discloses a CO low-temperature rectification process for separating a rectification section from a stripping section. According to the method, firstly, gas rich in 13C components is obtained through two-stage rectification, then, 12C is removed through treatment of an isotope scrambler, finally, N2 in the mixed gas is further removed through first-stage rectification, N2 is recycled to provide a cold source, and a high-abundance 13C product is obtained. According to the invention, the rectifying section and the stripping section are separated to carry out the rectifying process, so that the installation height of the device is greatly reduced, and the problem that the existing rectifying tower device is slender and great difficulty is brought to engineering practice is solved.

Description

Technical Field

[0001] The invention relates to the technical field of separation and purification of substances, and in particular to a CO low-temperature distillation process for separating a distillation section and a stripping section. Background Art

[0002] Stable isotopes play an increasingly important role in the development of the national economy due to their excellent physical and chemical properties. 13 As tracer atoms, C isotopes have been widely used in various research fields such as life sciences, clinical diagnosis, food safety, ecological environment, new drug development, metabolism, etc. 13 There are many methods for separating C isotopes, such as thermal diffusion, ion exchange, chromatography, chemical exchange, membrane separation, cryogenic distillation, etc. 13 The main method for industrial production of C isotopes is cryogenic distillation. 13 C isotope products are mainly obtained by optimizing the scrambler materials and impurity removal devices.

[0003] However, in the cryogenic distillation of CO, stable isotopes are separated. 13 In the process of CO2 distillation, due to the low temperature (-196℃), small separation coefficient (<1.01), high number of theoretical plates (about 2000-3000), vacuum distillation (negative pressure operation), high insulation requirements (small flow and lowest temperature liquid are very volatile), and slender production equipment, it brings great difficulties to engineering practice. Therefore, the field urgently needs to develop a CO2 low-temperature distillation process with low installation height, energy saving, high yield, and separation of the distillation section and the stripping section. Summary of the invention

[0004] The purpose of the present invention is to provide a CO low temperature distillation process which separates the distillation section and the stripping section, so as to solve the existing CO low temperature distillation separation of stable isotopes. 13 The process of C has the problems of harsh reaction conditions and slender production equipment.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The present invention provides a CO low-temperature distillation process for separating a distillation section and a stripping section, comprising the following steps:

[0007] (1) CO is fed through the lower part of the distillation tower A and subjected to a first distillation treatment to obtain a first distillation gas and a first spray liquid; the first distillation gas is discharged through the top of the distillation tower A and sold as a chemical raw material;

[0008] (2) The first spray liquid is fed through the upper part of the stripping tower A and undergoes a first stripping treatment to obtain a first stripping gas;

[0009] (3) A portion of the first stripping gas rises to the top of the stripping tower A and flows back to the distillation tower A for circulation; another portion of the first stripping gas is driven by the pressure difference to be fed through the lower part of the distillation tower B, and undergoes a second distillation treatment to obtain a second distillate;

[0010] (4) A portion of the second distillate flows back to the distillation tower A for circulation; another portion of the second distillate is fed through the upper portion of the distillation tower B, and undergoes a second distillation treatment to obtain a second stripping gas and condensed CO vapor; the condensed CO vapor returns to the distillation tower B under the action of gravity to achieve vapor-liquid reflux;

[0011] (5) the second stripping gas is converted by an isotope scrambler to obtain a separation gas;

[0012] (6) The separated gas is fed through the lower part of the distillation tower C under the pressure difference, and undergoes the third distillation treatment to obtain the third distillate;

[0013] (7) A portion of the third distillate flows back to the stripping tower B for circulation; another portion of the third distillate is fed to the upper portion of the stripping tower C, and undergoes the third distillation treatment to complete distillation, thereby obtaining 13 C product.

[0014] Preferably, a condenser is disposed at the top of the distillation tower A, the distillation tower B and the distillation tower C; and a reboiler is disposed at the bottom of the distillation tower A, the distillation tower B and the distillation tower C.

[0015] Preferably, in the first distillation treatment, the temperature at the top of the tower is 90-95K, the pressure at the top of the tower is 20-21psia, the temperature in the tower is 160-190K, the pressure in the tower is 30-35psia, the temperature at the bottom of the tower is 295-305K, the pressure at the bottom of the tower is 38-40psia, and the gas flow rate is 300-320g / h; in the first stripping treatment, the temperature at the top of the tower is 245-260K, the pressure at the top of the tower is 30-35psia, the temperature in the tower is 275-290K, the pressure in the tower is 32-36psia, the temperature at the bottom of the tower is 295-305K, and the pressure at the bottom of the tower is 41-43psia.

[0016] Preferably, in the second distillation treatment, the temperature at the top of the tower is 92-95K, the pressure at the top of the tower is 20-21psia, the temperature in the tower is 140-160K, the pressure in the tower is 30-35psia, the temperature at the bottom of the tower is 295-305K, the pressure at the bottom of the tower is 38-40psia, and the gas flow rate is 80-90g / h; in the second stripping treatment, the temperature at the top of the tower is 250-260K, the pressure at the top of the tower is 30-35psia, the temperature in the tower is 275-290K, the pressure in the tower is 32-36psia, the temperature at the bottom of the tower is 295-300K, and the pressure at the bottom of the tower is 41-43psia.

[0017] Preferably, the operating temperature of the isotope scrambler is 20-500°C.

[0018] Preferably, in the third distillation treatment, the temperature at the top of the tower is 100-120K, the pressure at the top of the tower is 25-28psia, the temperature in the tower is 140-160K, the pressure in the tower is 30-35psia, the temperature at the bottom of the tower is 295-305K, the pressure at the bottom of the tower is 38-40psia, and the gas flow rate is 70-75g / h; in the third stripping treatment, the temperature at the top of the tower is 275-280K, the pressure at the top of the tower is 30-35psia, the temperature in the tower is 275-290K, the pressure in the tower is 34-36psia, the temperature at the bottom of the tower is 295-300K, and the pressure at the bottom of the tower is 41-43psia.

[0019] Preferably, 2 to 10 distillation columns are independently arranged in the distillation tower A, the distillation tower B, the distillation tower C, the distillation tower A, the distillation tower B and the distillation tower C.

[0020] Preferably, the distillation columns of the distillation tower A, the distillation tower B and the distillation tower C are independently filled with structured packings; the structured packings independently include plate corrugated packings and wire mesh corrugated packings.

[0021] Preferably, the diameters of the distillation tower A, the distillation tower B, the distillation tower C, the distillation tower A, the distillation tower B and the distillation tower C are independently 0.1 to 2 m.

[0022] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The CO low-temperature distillation process of separating the distillation section and the stripping section of the present invention greatly reduces the installation height of the device and solves the existing CO low-temperature distillation separation of stable isotopes. 13 The production equipment used in process C is long and thin, which brings great difficulties to engineering practice;

[0024] (2) The CO low-temperature distillation process of separating the distillation section and the stripping section according to the present invention can save energy consumption, and the by-products produced can be collected to supplement the energy consumed by the distillation process; the vaporized nitrogen produced after the third stripping treatment can be collected as a cold source for the condenser;

[0025] (3) The present invention can significantly improve the yield through three-stage distillation and isotope scrambler coordinated processing. 13 The abundance of C products; firstly, the rich 13 The C component gas is then processed through an isotope scrambler to remove 12 C, and finally the N2 in the mixed gas is further removed by a first-stage distillation, and the N2 is recovered to provide a cold source to obtain a high-abundance 13 C product. DETAILED DESCRIPTION

[0026] The present invention provides a CO low-temperature distillation process for separating a distillation section and a stripping section, comprising the following steps:

[0027] (1) CO is fed through the lower part of the distillation tower A and subjected to a first distillation treatment to obtain a first distillation gas and a first spray liquid; the first distillation gas is discharged through the top of the distillation tower A and sold as a chemical raw material;

[0028] (2) The first spray liquid is fed through the upper part of the stripping tower A and undergoes a first stripping treatment to obtain a first stripping gas;

[0029] (3) A portion of the first stripping gas rises to the top of the stripping tower A and flows back to the distillation tower A for circulation; another portion of the first stripping gas is driven by the pressure difference to be fed through the lower part of the distillation tower B, and undergoes a second distillation treatment to obtain a second distillate;

[0030] (4) A portion of the second distillate flows back to the distillation tower A for circulation; another portion of the second distillate is fed through the upper portion of the distillation tower B, and undergoes a second distillation treatment to obtain a second stripping gas and condensed CO vapor; the condensed CO vapor returns to the distillation tower B under the action of gravity to achieve vapor-liquid reflux;

[0031] (5) the second stripping gas is converted by an isotope scrambler to obtain a separation gas;

[0032] (6) The separated gas is fed through the lower part of the distillation tower C under the pressure difference, and undergoes the third distillation treatment to obtain the third distillate;

[0033] (7) A portion of the third distillate flows back to the stripping tower B for circulation; another portion of the third distillate is fed to the upper portion of the stripping tower C, and undergoes the third distillation treatment to complete distillation, thereby obtaining 13 C product.

[0034] In the present invention, condensers are arranged at the tops of the distillation tower A, the distillation tower B and the distillation tower C; and reboilers are arranged at the bottoms of the distillation tower A, the distillation tower B and the distillation tower C.

[0035] In the first distillation treatment of the present invention, the temperature at the top of the tower is preferably 90-95K, and more preferably 92-94K; the pressure at the top of the tower is preferably 20-21psia, and more preferably 20.2-20.5psia; the temperature in the tower is preferably 160-190K, and more preferably 170-180K; the pressure in the tower is preferably 30-35psia, and more preferably 32-34psia; the temperature at the bottom of the tower is preferably 295-305K, and more preferably 298-300K; the pressure at the bottom of the tower is preferably 38-40psia, and more preferably 38.5-39psia; the gas flow rate is preferably 300-320g / h, and more preferably 310-315g / h.

[0036] In the first distillation treatment of the present invention, the temperature at the top of the tower is preferably 245-260K, more preferably 250-255K; the pressure at the top of the tower is preferably 30-35psia, more preferably 32-34psia; the temperature in the tower is preferably 275-290K, more preferably 280-285K; the pressure in the tower is preferably 32-36psia, more preferably 33-35psia; the temperature at the bottom of the tower is preferably 295-305K, more preferably 300-302K; the pressure at the bottom of the tower is preferably 41-43psia, more preferably 42-42.5psia.

[0037] In the second distillation treatment of the present invention, the temperature at the top of the tower is preferably 92-95K, and more preferably 93-94K; the pressure at the top of the tower is preferably 20-21psia, and more preferably 20.5-20.8psia; the temperature in the tower is preferably 140-160K, and more preferably 150-155K; the pressure in the tower is preferably 30-35psia, and more preferably 32-34psia; the temperature at the bottom of the tower is preferably 295-305K, and more preferably 300-302K; the pressure at the bottom of the tower is preferably 38-40psia, and more preferably 38.5-39psia; the gas flow rate is preferably 80-90g / h, and more preferably 82-85g / h.

[0038] In the second distillation treatment of the present invention, the temperature at the top of the tower is preferably 250-260K, more preferably 255-257K; the pressure at the top of the tower is preferably 30-35psia, more preferably 32-34psia; the temperature in the tower is preferably 275-290K, more preferably 280-285K; the pressure in the tower is preferably 32-36psia, more preferably 33-35psia; the temperature at the bottom of the tower is preferably 295-300K, more preferably 297-299K; the pressure at the bottom of the tower is preferably 41-43psia, more preferably 42-42.5psia.

[0039] In the present invention, the working temperature of the isotope scrambler is preferably 20-500° C., more preferably 50-400° C.; the gas flow rate of the isotope scrambler is preferably 20-30 kg / hr, more preferably 22.3-26.7 kg / hr.

[0040] In the present invention, the scrambling material filled in the isotope scrambler includes one or more of metal elements, alloys and oxides of Ni, Cu, Zn, Co, Al, Mg, Ca, B, Fe, Ti, Zr, Cr, Mo, Mn, Ba, Pd, Ir, Pt and Ag.

[0041] In the third distillation treatment of the present invention, the temperature at the top of the tower is preferably 100-120K, and more preferably 110-115K; the pressure at the top of the tower is preferably 25-28psia, and more preferably 26-27psia; the temperature in the tower is preferably 140-160K, and more preferably 150-155K; the pressure in the tower is preferably 30-35psia, and more preferably 32-34psia; the temperature at the bottom of the tower is preferably 295-305K, and more preferably 300-302K; the pressure at the bottom of the tower is preferably 38-40psia, and more preferably 39-39.5psia; the gas flow rate is preferably 70-75g / h, and more preferably 72-74g / h.

[0042] In the third distillation treatment of the present invention, the temperature at the top of the tower is preferably 275-280K, more preferably 277-279K; the pressure at the top of the tower is preferably 30-35psia, more preferably 32-34psia; the temperature in the tower is preferably 275-290K, more preferably 277-282K; the pressure in the tower is preferably 34-36psia, more preferably 35-35.5psia; the temperature at the bottom of the tower is preferably 295-300K, more preferably 297-299K; the pressure at the bottom of the tower is preferably 41-43psia, more preferably 42-42.5psia.

[0043] In the present invention, it is preferred that 2 to 10 distillation columns are independently provided in the distillation tower A, the distillation tower B, the distillation tower C, the stripping tower A, the stripping tower B and the distillation tower C, and it is more preferred that 4 to 8 distillation columns are provided.

[0044] In the present invention, the distillation columns of the stripping tower A, the stripping tower B and the stripping tower C are independently filled with structured packings; the structured packings independently include plate corrugated packings and wire mesh corrugated packings; the specific surface area of ​​the structured packings is independently preferably 500 to 2000 m 2 / m 3 , more preferably 1000 to 1500 m 2 / m 3 .

[0045] In the present invention, the diameters of the distillation tower A, the distillation tower B, the distillation tower C, the distillation tower A, the distillation tower B and the distillation tower C are independently preferably 0.1 to 2 m, and more preferably 0.5 to 1.1 m.

[0046] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0047] Example 1

[0048] The high-purity raw material CO is introduced into a distillation tower A (there are 10 distillation columns for the cascade reaction), and the top temperature is controlled to be 92K, the top pressure is 20.2psia, the temperature in the tower is 180K, the pressure in the tower is 32psia, the bottom temperature is 298K, the bottom pressure is 38.5psia, and the gas flow rate is 315g / h for the first distillation treatment. CO forms a first spray liquid under the action of the condenser at the top of the distillation tower A and flows to the bottom of the tower. Another part of the gas is discharged from the top of the distillation tower A and sold as a chemical raw material; the first spray liquid is pumped from the bottom of the distillation tower A into a stripping tower A (there are 10 distillation columns for the cascade reaction), and the top temperature is controlled to be 245K, the top pressure is 30psia, the tower temperature is 280K, and the tower The first distillation treatment is carried out at a pressure of 32 psia, a tower bottom temperature of 295K, and a tower bottom pressure of 41 psia. In the distillation tower A, the first spray liquid flows into the tower kettle through the structured packing and is heated and vaporized. A part of it flows upward in the distillation tower A and exchanges with the descending liquid, and the other part enters the top of the distillation tower B (there are 4 distillation columns for the cascade reaction) under the promotion of the pressure difference. The tower top temperature is controlled to be 95K, the tower top pressure is 20.8 psia, the tower temperature is 150K, the tower pressure is 32 psia, the tower bottom temperature is 295K, the tower bottom pressure is 38.5 psia, and the gas flow rate is 82 g / h for the second distillation treatment. The gas forms the second distillate under the action of the condenser at the top of the distillation tower B, and a part of it flows back to the distillation tower A is circulated, and the other part is fed through the upper part of the stripping tower B (there are 4 distillation columns for the cascade reaction), and the top temperature of the tower is controlled to be 255K, the top pressure of the tower is 30psia, the temperature in the tower is 280K, the pressure in the tower is 33psia, the bottom temperature of the tower is 297K, and the bottom pressure of the tower is 42.5psia for the second stripping treatment. In the stripping tower B, the liquid flows into the tower kettle through the structured packing and is heated and vaporized to obtain the second stripping gas and condensed CO vapor; the condensed CO vapor returns to the distillation tower B under the action of gravity to realize vapor-liquid reflux; a part of the second stripping gas flows upward in the stripping tower B to exchange with the descending liquid, and the other part of the second stripping gas enters the isotope scrambler driven by the pressure difference, and the temperature is set to 400 ℃, gas flow rate is 26.7kg / hr, the gas after isotope scrambler enters the top of distillation tower C (two distillation columns for cascade reaction), the top temperature is controlled to be 120K, the top pressure is 25psia, the temperature in the tower is 155K, the pressure in the tower is 34psia, the bottom temperature is 300K, the bottom pressure is 39psia, the gas flow rate is 74g / h for the third distillation treatment, the gas forms the third distillation liquid under the action of the condenser at the top of distillation tower C, part of it flows back to stripping tower B for circulation, and the other part is fed through the upper part of stripping tower C (two distillation columns for cascade reaction), the top temperature is controlled to be 277K, the top pressure is 32psia, the temperature in the tower is 282K, and the pressure in the tower is 35.5psia, the tower bottom temperature is 299K, the tower bottom pressure is 42.5psia for the third distillation treatment, in the distillation tower C, the liquid flows into the tower kettle through the structured packing and is heated and vaporized to obtain. 13 C product, and at the same time, the vaporized nitrogen produced can be collected as the cold source of the condenser.

[0049] In this embodiment, the abundance of the gas obtained after the second distillation treatment is 99.98%. 13 The abundance of product C is 99.999%.

[0050] Example 2

[0051] The high-purity raw material CO is introduced into the distillation tower A (the cascade reaction has 8 distillation columns), and the top temperature is controlled to be 94K, the top pressure is 20.5psia, the temperature in the tower is 170K, the pressure in the tower is 32psia, the bottom temperature is 300K, the bottom pressure is 38psia, and the gas flow rate is 310g / h for the first distillation treatment. CO forms the first spray liquid under the action of the condenser at the top of the distillation tower A, and flows to the bottom of the tower. Another part of the gas is discharged from the top of the distillation tower A and sold as a chemical raw material; the first spray liquid is pumped from the bottom of the distillation tower A into the stripping tower A (the cascade reaction has 8 distillation columns), and the top is controlled to be The first distillation treatment is carried out at a temperature of 250K, a pressure of 32psia at the top of the tower, a temperature of 275K in the tower, a pressure of 33psia in the tower, a temperature of 295K in the tower, and a pressure of 41psia at the bottom of the tower. In the distillation tower A, the first spray liquid flows into the tower kettle through the structured packing and is heated and vaporized. A part of it flows upward in the distillation tower A and exchanges with the descending liquid, and the other part enters the top of the distillation tower B (there are 4 distillation columns in the cascade reaction) under the promotion of the pressure difference. The top temperature of the tower is controlled to be 93K, the top pressure is 20.5psia, the temperature in the tower is 155K, the pressure in the tower is 32psia, and the bottom temperature is 300K. , the bottom pressure is 39psia, and the gas flow rate is 80g / h for the second distillation treatment. The gas forms a second distillation liquid under the action of the condenser at the top of the distillation tower B. A part of it flows back to the distillation tower A for circulation, and the other part is fed through the upper part of the distillation tower B (there are 4 distillation columns in the cascade reaction). The top temperature is controlled to be 257K, the top pressure is 30psia, the temperature in the tower is 280K, the pressure in the tower is 35psia, the bottom temperature is 299K, and the bottom pressure is 42psia for the second distillation treatment. In the distillation tower B, the liquid flows into the tower kettle through the structured packing and is heated and vaporized to obtain the second stripping gas and the condensed CO vapor; the condensed CO vapor returns to the distillation tower B under the action of gravity to realize vapor-liquid reflux; a part of the second stripping gas flows upward in the distillation tower B to exchange with the descending liquid, and another part of the second stripping gas enters the isotope scrambler under the pressure difference, and the temperature is set to 500°C, the gas flow rate is 22.3kg / hr, and the gas passing through the isotope scrambler enters the top of the distillation tower C (there are 2 distillation columns in the cascade reaction), and the top temperature is controlled to be 110K, the top pressure is 27psia, the temperature in the tower is 160K, the pressure in the tower is 32psia, the bottom temperature is 300K, and the bottom pressure is 39.5psia, gas flow rate of 72g / h for the third distillation treatment, the gas under the action of the condenser at the top of the distillation tower C forms the third distillation liquid, a part of it flows back to the distillation tower B for circulation, and the other part is fed through the upper part of the distillation tower C (the cascade reaction has two distillation columns), the tower top temperature is controlled to be 279K, the tower top pressure is 34psia, the tower temperature is 290K, the tower pressure is 36psia, the tower bottom temperature is 295K, and the tower bottom pressure is 42psia for the third distillation treatment, in the distillation tower C, the liquid flows into the tower kettle through the structured packing and is heated and vaporized to obtain. 13 C product, and at the same time, the vaporized nitrogen produced can be collected as the cold source of the condenser.

[0052] In this embodiment, the abundance of the gas obtained after the second distillation treatment is 99.97%. 13 The abundance of product C is 99.998%.

[0053] Example 3

[0054] The high-purity raw material CO is introduced into the distillation tower A (the number of distillation columns for the cascade reaction is 10), and the top temperature is controlled to be 95K, the top pressure is controlled to be 21psia, the temperature in the tower is controlled to be 180K, the pressure in the tower is controlled to be 34psia, the bottom temperature is controlled to be 300K, the bottom pressure is controlled to be 38psia, and the gas flow rate is 300g / h for the first distillation treatment. CO forms the first spray liquid under the action of the condenser at the top of the distillation tower A, and flows to the bottom of the tower. Another part of the gas is discharged from the top of the distillation tower A and sold as a chemical raw material; the first spray liquid is pumped from the bottom of the distillation tower A into the stripping tower A (the number of distillation columns for the cascade reaction is 10), and the top is controlled to be The first distillation treatment is carried out at a temperature of 255K, a pressure of 34psia at the top of the tower, a temperature of 275K in the tower, a pressure of 33psia at the bottom of the tower, a temperature of 300K in the tower, and a pressure of 41psia at the bottom of the tower. In the distillation tower A, the first spray liquid flows into the tower kettle through the structured packing and is heated and vaporized. A part of it flows upward in the distillation tower A and exchanges with the descending liquid, and the other part enters the top of the distillation tower B (there are 8 distillation columns in the cascade reaction) under the promotion of the pressure difference. The top temperature of the tower is controlled to be 95K, the top pressure is 20psia, the tower temperature is 150K, the tower pressure is 30psia, the tower bottom temperature is 300K, and the tower The bottom pressure is 38psia, and the gas flow rate is 85g / h for the second distillation treatment. The gas forms a second distillation liquid under the action of the condenser at the top of the distillation tower B. A part of it flows back to the distillation tower A for circulation, and the other part is fed through the upper part of the distillation tower B (the distillation columns of the cascade reaction are 8). The top temperature of the tower is controlled to be 255K, the top pressure of the tower is 32psia, the temperature in the tower is 285K, the pressure in the tower is 35psia, the bottom temperature of the tower is 300K, and the bottom pressure of the tower is 42.5psia for the second distillation treatment. In the distillation tower B, the liquid flows into the tower kettle through the structured packing and is heated and vaporized to obtain the second stripping gas and the condensed CO vapor; the condensed CO vapor returns to the distillation tower B under the action of gravity to realize vapor-liquid reflux; a part of the second stripping gas flows upward in the distillation tower B to exchange with the descending liquid, and another part of the second stripping gas enters the isotope scrambler under the pressure difference, and the temperature is set to 500°C, the gas flow rate is 26.7kg / hr, and the gas passing through the isotope scrambler enters the top of the distillation tower C (there are 2 distillation columns in the cascade reaction), and the top temperature is controlled to be 115K, the top pressure is 28psia, the tower temperature is 155K, the tower pressure is 34psia, the tower bottom temperature is 300K, and the tower bottom pressure is 39.5psia, gas flow rate of 70g / h for the third distillation treatment, the gas under the action of the condenser at the top of the distillation tower C forms the third distillation liquid, a part of it flows back to the distillation tower B for circulation, and the other part is fed through the upper part of the distillation tower C (the cascade reaction has two distillation columns), the tower top temperature is controlled to be 280K, the tower top pressure is 32psia, the tower temperature is 282K, the tower pressure is 36psia, the tower bottom temperature is 295K, and the tower bottom pressure is 41psia for the third distillation treatment, in the distillation tower C, the liquid flows into the tower kettle through the structured packing and is heated and vaporized to obtain. 13 C product, and at the same time, the vaporized nitrogen produced can be collected as the cold source of the condenser.

[0055] In this embodiment, the abundance of the gas obtained after the second distillation treatment is 99.97%. 13 The abundance of product C is 99.999%.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A CO cryogenic distillation process with a separation of a distillation section and a stripping section, characterized in that: The steps include: (1) CO is fed through the lower part of the distillation tower A and subjected to a first distillation treatment to obtain a first distillation gas and a first spray liquid; the first distillation gas is discharged through the top of the distillation tower A and sold as a chemical raw material; (2) The first spray liquid is fed through the upper part of the stripping tower A and undergoes a first stripping treatment to obtain a first stripping gas; (3) A portion of the first stripping gas rises to the top of the stripping tower A and flows back to the distillation tower A for circulation; another portion of the first stripping gas is driven by the pressure difference to be fed through the lower part of the distillation tower B, and undergoes a second distillation treatment to obtain a second distillate; (4) a portion of the second distillate flows back to the distillation tower A for circulation; Another part of the second distillate is fed through the upper part of the stripping tower B, and undergoes a second stripping treatment to obtain a second stripping gas and condensed CO vapor; The condensed CO vapor returns to the distillation tower B under the action of gravity to achieve vapor-liquid reflux; (5) the second stripping gas is converted by an isotope scrambler to obtain a separation gas; (6) The separated gas is fed through the lower part of the distillation tower C under the pressure difference, and undergoes the third distillation treatment to obtain the third distillate; (7) A portion of the third distillate flows back to the stripping tower B for circulation; Another part of the third distillate is fed through the upper part of the stripping tower C, and after the third stripping treatment, the distillation is completed to obtain 13 C product.

2. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to claim 1, characterized in that: Condensers are arranged at the tops of the distillation tower A, the distillation tower B and the distillation tower C; and reboilers are arranged at the bottoms of the distillation tower A, the distillation tower B and the distillation tower C.

3. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to claim 2, characterized in that: In the first distillation treatment, the temperature at the top of the tower is 90-95K, the pressure at the top of the tower is 20-21psia, the temperature in the tower is 160-190K, the pressure in the tower is 30-35psia, the temperature at the bottom of the tower is 295-305K, the pressure at the bottom of the tower is 38-40psia, and the gas flow rate is 300-320g / h; in the first stripping treatment, the temperature at the top of the tower is 245-260K, the pressure at the top of the tower is 30-35psia, the temperature in the tower is 275-290K, the pressure in the tower is 32-36psia, the temperature at the bottom of the tower is 295-305K, and the pressure at the bottom of the tower is 41-43psia.

4. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to any one of claims 1 to 3, characterized in that: In the second distillation treatment, the temperature at the top of the tower is 92-95K, the pressure at the top of the tower is 20-21psia, the temperature in the tower is 140-160K, the pressure in the tower is 30-35psia, the temperature at the bottom of the tower is 295-305K, the pressure at the bottom of the tower is 38-40psia, and the gas flow rate is 80-90g / h; in the second stripping treatment, the temperature at the top of the tower is 250-260K, the pressure at the top of the tower is 30-35psia, the temperature in the tower is 275-290K, the pressure in the tower is 32-36psia, the temperature at the bottom of the tower is 295-300K, and the pressure at the bottom of the tower is 41-43psia.

5. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to claim 4, characterized in that: The working temperature of the isotope scrambler is 20-500°C.

6. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to claim 5, characterized in that: In the third distillation treatment, the temperature at the top of the tower is 100-120K, the pressure at the top of the tower is 25-28psia, the temperature in the tower is 140-160K, the pressure in the tower is 30-35psia, the temperature at the bottom of the tower is 295-305K, the pressure at the bottom of the tower is 38-40psia, and the gas flow rate is 70-75g / h; in the third stripping treatment, the temperature at the top of the tower is 275-280K, the pressure at the top of the tower is 30-35psia, the temperature in the tower is 275-290K, the pressure in the tower is 34-36psia, the temperature at the bottom of the tower is 295-300K, and the pressure at the bottom of the tower is 41-43psia.

7. The CO cryogenic distillation process with separation of the distillation section and the stripping section according to claim 5 or 6, characterized in that: The distillation tower A, the distillation tower B, the distillation tower C, the distillation tower A, the distillation tower B and the distillation tower C are independently provided with 2 to 10 distillation columns.

8. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to claim 7, characterized in that: The rectifying columns of the distillation tower A, the distillation tower B and the distillation tower C are independently filled with structured packings; the structured packings independently include plate corrugated packings and wire mesh corrugated packings.

9. The CO cryogenic distillation process for separating the rectifying section and the stripping section according to claim 8, characterized in that: The tower diameters of the distillation tower A, the distillation tower B, the distillation tower C, the distillation tower A, the distillation tower B and the distillation tower C are independently 0.1 to 2 m.