阅读说明：本技术 一种二氧化碳提纯工艺 (Carbon dioxide purification process ) 是由 沈剑男 戴荣国 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种二氧化碳提纯工艺,所述提纯工艺包括以下步骤：S1：二氧化碳分离→S2：二氧化碳化学提纯→S3：二氧化碳物理提纯,其中二氧化碳化学提纯包括脱除二氧化碳中硫化物、催化燃烧以及H-2O、O-2、N-2杂质的去除,二氧化碳物理提纯则为变化吸附法纯。本发明通过化学提纯,对二氧化碳做脱除二氧化碳中硫化物、催化燃烧以及H-2O、O-2、N-2杂质的去除,完成对二氧化碳的第一次提纯处理,再对二氧化碳做变压吸附提纯,不仅有效地提高二氧化碳的整体纯度,而且提纯成本低,提纯后二氧化碳的纯度达到5N以上,完全满足激光气配制、电子工业、反应堆气体冷却剂、科学研究等领域的应用,具有良好的市场前景。(The invention discloses a carbon dioxide purification process, which comprises the following steps: s1: carbon dioxide separation → S2: chemical purification of carbon dioxide → S3: physical purification of carbon dioxide, wherein chemical purification of carbon dioxide comprises removal of sulfides in carbon dioxide, catalytic combustion and H 2 O、O 2 、N 2 And removing impurities, wherein the carbon dioxide physical purification is pure by a variable adsorption method. The invention removes sulfide in carbon dioxide, catalyzes combustion and H in the carbon dioxide by chemical purification 2 O、O 2 、N 2 The impurities are removed, the first purification treatment of the carbon dioxide is completed, and then the carbon dioxide is purified by pressure swing adsorption, so that the overall purity of the carbon dioxide is effectively improved, the purification cost is low, the purity of the purified carbon dioxide reaches more than 5N, the application in the fields of laser gas preparation, electronic industry, reactor gas coolant, scientific research and the like is completely met, and the method has a good market prospect.)

1. A carbon dioxide purification process is characterized in that: the purification process comprises the following steps:

s1: carbon dioxide separation

Placing gas in an exchange box, placing an organic solvent in the exchange box, absorbing carbon dioxide by utilizing the pressure and temperature between the alternating carbon dioxide and the organic solvent so as to separate the carbon dioxide, then placing the separated carbon dioxide in an absorption tower, reacting the carbon dioxide in the absorption tower through a chemical solvent to promote the carbon dioxide to enter the solvent, introducing a formed pregnant solution into a desorption tower, heating, decomposing, absorbing and desorbing to obtain separated carbon dioxide, and passing the carbon dioxide gas through a membrane material to obtain finally separated carbon dioxide;

s2: chemical purification of carbon dioxide

A. Removing sulfide in carbon dioxide: putting the carbon dioxide obtained in the step S1 into a desulfurizing tower, and hydrolyzing COS into H under the catalytic action of a desulfurizing agent₂S, H in carbon dioxide at this time₂S and H formed by hydrolysis₂S and O₂Elemental sulfur is generated through the action and is absorbed and removed by active carbon in the desulfurizing tower;

B. catalytic combustion: placing carbon dioxide in a dealkylation tower, catalytically oxidizing combustible gas components in the carbon dioxide into carbon dioxide and hydrogen dioxide, removing total hydrocarbon, carbon monoxide and hydrogen in the carbon dioxide during catalytic combustion, wherein the carbon dioxide catalytic reaction is as follows:

2H₂+O₂→2H₂O

2CO+O₂→2CO₂

CH₄+2O₂→CO₂+2H₂O

drying the purified carbon dioxide in a drying tower, and removing water by using a 3A molecular sieve;

C、H₂O、O₂、N₂and (3) removing impurities: firstly, removing nitrogen impurities in carbon dioxide by using distillation equipment, then placing the carbon dioxide in a deoxygenation tower, and removing the residual oxygen by using a noble metal high-efficiency deoxygenation catalyst to complete a chemical purification process of the carbon dioxide;

s3: physical purification of carbon dioxide

And (2) placing the chemically purified carbon dioxide into a pressure-changing cylinder, placing an adsorbent into the pressure-changing cylinder to increase the pressure inside the pressure-changing cylinder, separating the mixed gas in the carbon dioxide, then reducing the pressure inside the pressure-changing cylinder, regenerating the adsorbent, continuously increasing the pressure inside the pressure-changing cylinder, separating the mixed gas in the carbon dioxide again, repeating the steps, continuously pressurizing and depressurizing the pressure-changing cylinder, realizing multiple separation of the mixed gas in the carbon dioxide and multiple use of the adsorbent, and injecting the carbon dioxide into a sealed tank for storage after purification is completed.

2. The carbon dioxide purification process according to claim 1, wherein: in the step S1, the pressure inside the exchange box is set to 130Pa, the temperature is set to 90 ℃, the pressure inside the absorption tower is set to 80Pa, the temperature is set to 120 ℃, and the membrane material is a polyamide membrane, a polysulfone membrane, a cellulose acetate membrane, or a polyether sulfone membrane.

3. The carbon dioxide purification process according to claim 1, wherein: in the step S2, the temperature inside the desulfurizing tower is set to 110 ℃, the desulfurizing time is 2h, the temperature inside the dealkylating tower is set to 350 ℃, the dealkylating time is 1.5h, and the carbon dioxide moisture removal precision is 0.1x10^-6The residual oxygen content of the deoxidized carbon dioxide is less than 0.1x10^-6。

4. The carbon dioxide purification process according to claim 1, wherein: in the step S3, the maximum pressure inside the pressure changing cylinder is 210-230Pa, the minimum pressure inside the pressure changing cylinder is 80-110Pa, and the number of times of continuously increasing and decreasing the pressure inside the pressure changing cylinder is 8-10 times.

Technical Field

The invention relates to the technical field of carbon dioxide processing, in particular to a carbon dioxide purification process.

Background

Carbon dioxide is a carbon oxide, is a colorless and tasteless or colorless and odorless gas at normal temperature and normal pressure, has a slightly sour water solution, is also a common greenhouse gas, is one of components of air, has a melting point of-56.6 ℃, a boiling point of-78.5 ℃ and a density higher than that of air in terms of physical properties, is soluble in water, is chemically inert, has high thermal stability, cannot combust, generally cannot support combustion, belongs to an acidic oxide, has the universality of the acidic oxide, and is carbonic acid anhydride due to the fact that carbonic acid is generated by reaction with water;

the carbon dioxide can be prepared by high-temperature calcined limestone or by the reaction of limestone and dilute hydrochloric acid, is mainly applied to refrigeration of perishable foods, refrigerant, preparation of carbonized soft drinks, solvent for homogeneous reaction and the like, and researches show that the toxicity of the carbon dioxide is low in concentration, the carbon dioxide is nontoxic, animals are poisoned by high-concentration carbon dioxide, and purification treatment is needed after the preparation of the carbon dioxide.

The prior art has the following defects: the existing purification method of carbon dioxide is single, only purification by a physical method or a chemical method is adopted, other impurities are remained in the purified carbon dioxide, the purification effect of the carbon dioxide is poor, and the purification cost is high.

Disclosure of Invention

The invention provides a carbon dioxide purification process to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a carbon dioxide purification process, the purification process comprising the steps of:

s1: carbon dioxide separation

Placing gas in an exchange box, placing an organic solvent in the exchange box, absorbing carbon dioxide by utilizing the pressure and temperature between the alternating carbon dioxide and the organic solvent so as to separate the carbon dioxide, then placing the separated carbon dioxide in an absorption tower, reacting the carbon dioxide in the absorption tower through a chemical solvent to promote the carbon dioxide to enter the solvent, introducing a formed pregnant solution into a desorption tower, heating, decomposing, absorbing and desorbing to obtain separated carbon dioxide, and passing the carbon dioxide gas through a membrane material to obtain finally separated carbon dioxide;

s2: chemical purification of carbon dioxide

A. Removing sulfide in carbon dioxide: putting the carbon dioxide obtained in the step S1 into a desulfurizing tower, and hydrolyzing COS into H under the catalytic action of a desulfurizing agent₂S, H in carbon dioxide at this time₂S and H formed by hydrolysis₂S andO₂elemental sulfur is generated through the action and is absorbed and removed by active carbon in the desulfurizing tower;

B. catalytic combustion: placing carbon dioxide in a dealkylation tower, catalytically oxidizing combustible gas components in the carbon dioxide into carbon dioxide and hydrogen dioxide, removing total hydrocarbon, carbon monoxide and hydrogen in the carbon dioxide during catalytic combustion, wherein the carbon dioxide catalytic reaction is as follows:

2H₂+O₂→2H₂O

2CO+O₂→2CO₂

CH₄+2O₂→CO₂+2H₂O

drying the purified carbon dioxide in a drying tower, and removing water by using a 3A molecular sieve;

C、H₂O、O₂、N₂and (3) removing impurities: firstly, removing nitrogen impurities in carbon dioxide by using distillation equipment, then placing the carbon dioxide in a deoxygenation tower, and removing the residual oxygen by using a noble metal high-efficiency deoxygenation catalyst to complete a chemical purification process of the carbon dioxide;

s3: physical purification of carbon dioxide

And (2) placing the chemically purified carbon dioxide into a pressure-changing cylinder, placing an adsorbent into the pressure-changing cylinder to increase the pressure inside the pressure-changing cylinder, separating the mixed gas in the carbon dioxide, then reducing the pressure inside the pressure-changing cylinder, regenerating the adsorbent, continuously increasing the pressure inside the pressure-changing cylinder, separating the mixed gas in the carbon dioxide again, repeating the steps, continuously pressurizing and depressurizing the pressure-changing cylinder, realizing multiple separation of the mixed gas in the carbon dioxide and multiple use of the adsorbent, and injecting the carbon dioxide into a sealed tank for storage after purification is completed.

Preferably, in the step S1, the pressure inside the exchange box is set to 130Pa, the temperature is set to 90 ℃, the pressure inside the absorption tower is set to 80Pa, the temperature is set to 120 ℃, and the membrane material is a polyamide membrane, a polysulfone membrane, a cellulose acetate membrane or a polyether sulfone membrane.

Preferably, in the step S2, the temperature inside the desulfurization tower is set to 110 ℃, the desulfurization time is 2 hours, and the hydrocarbon is removedThe temperature in the tower is set to 350 ℃, the hydrocarbon removal time is 1.5h, and the carbon dioxide moisture removal precision is 0.1x10^-6The residual oxygen content of the deoxidized carbon dioxide is less than 0.1x10^-6。

Preferably, in the step S3, the maximum pressure in the pressure changing cylinder is 210-230Pa, the minimum pressure in the pressure changing cylinder is 80-110Pa, and the number of times of continuously increasing and decreasing the pressure in the pressure changing cylinder is 8-10 times.

The invention has the technical effects and advantages that:

the invention removes sulfide in carbon dioxide, catalyzes combustion and H in the carbon dioxide by chemical purification₂O、O₂、N₂The impurities are removed, the first purification treatment of the carbon dioxide is completed, then the carbon dioxide is purified by physical purification and pressure swing adsorption, so that the overall purity of the carbon dioxide is effectively improved, the purification cost is low, the purity of the purified carbon dioxide reaches more than 5N, the application in the fields of laser gas preparation, electronic industry, reactor gas coolant, scientific research and the like is completely met, and the method has a good market prospect.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a carbon dioxide purification process, which comprises the following steps:

s1: carbon dioxide separation

Placing gas in an exchange box, placing an organic solvent in the exchange box, absorbing carbon dioxide by utilizing the pressure and temperature between the alternating carbon dioxide and the organic solvent so as to separate the carbon dioxide, then placing the separated carbon dioxide in an absorption tower, reacting the carbon dioxide in the absorption tower through a chemical solvent to promote the carbon dioxide to enter the solvent, introducing a formed pregnant solution into a desorption tower, heating, decomposing, absorbing and desorbing to obtain separated carbon dioxide, and passing the carbon dioxide gas through a membrane material to obtain finally separated carbon dioxide;

s2: chemical purification of carbon dioxide

A. Removing sulfide in carbon dioxide: putting the carbon dioxide obtained in the step S1 into a desulfurizing tower, and hydrolyzing COS into H under the catalytic action of a desulfurizing agent₂S, H in carbon dioxide at this time₂S and H formed by hydrolysis₂S and O₂Elemental sulfur is generated through the action and is absorbed and removed by active carbon in the desulfurizing tower;

B. catalytic combustion: placing carbon dioxide in a dealkylation tower, catalytically oxidizing combustible gas components in the carbon dioxide into carbon dioxide and hydrogen dioxide, removing total hydrocarbon, carbon monoxide and hydrogen in the carbon dioxide during catalytic combustion, wherein the carbon dioxide catalytic reaction is as follows:

2H₂+O₂→2H₂O

2CO+O₂→2CO₂

CH₄+2O₂→CO₂+2H₂O

drying the purified carbon dioxide in a drying tower, and removing water by using a 3A molecular sieve;

C、H₂O、O₂、N₂and (3) removing impurities: firstly, removing nitrogen impurities in carbon dioxide by using distillation equipment, then placing the carbon dioxide in a deoxygenation tower, and removing the residual oxygen by using a noble metal high-efficiency deoxygenation catalyst to complete a chemical purification process of the carbon dioxide;

example 1: in the process, the cold energy of the liquid carbon dioxide is fully utilized, the optimal temperature required by desulfurization can be reached through heat exchange, the gaseous carbon dioxide is easier to liquefy, the energy consumption is reduced, and when the gas passes through the dealkylation tower, the gas temperature reaches 350 ℃, so that the methane, the carbon monoxide and the oxygen can quickly and fully react.

S3: physical purification of carbon dioxide

And (2) placing the chemically purified carbon dioxide into a pressure-changing cylinder, placing an adsorbent into the pressure-changing cylinder to increase the pressure inside the pressure-changing cylinder, separating the mixed gas in the carbon dioxide, then reducing the pressure inside the pressure-changing cylinder, regenerating the adsorbent, continuously increasing the pressure inside the pressure-changing cylinder, separating the mixed gas in the carbon dioxide again, repeating the steps, continuously pressurizing and depressurizing the pressure-changing cylinder, realizing multiple separation of the mixed gas in the carbon dioxide and multiple use of the adsorbent, and injecting the carbon dioxide into a sealed tank for storage after purification is completed.

Example 2: the pressure swing adsorption method has the advantages that:

1. the pressure swing adsorption device has the characteristic of very strong adaptability, the actual production capacity of the pressure swing adsorption device can be changed through fine adjustment, and the pressure swing adsorption device can also adapt to the inlet pressure of raw material gas and different process conditions, generally speaking, the adsorbent has a longer application period, usually about 10 years, and if some new adsorbents are added, the application period of the adsorbent can be prolonged;

2. the method has the advantages of low energy consumption, as for the pressure swing adsorption method, only pressurization is carried out in the process, power consumption can be caused, the working pressure is very low under the common condition, as for the vacuum desorption process, the purpose of pressurization is mainly realized by utilizing a blower, heating is not needed during the regeneration of the adsorbent, and the regeneration can be realized by a vacuum pump with low consumption;

3. because the pressure swing adsorption method mainly adopts gas-solid separation, the separated gas does not contain solvent vapor, so the problems of solvent loss and recovery can not occur, in the process, the operation automation can be realized, and the application effect is very obvious.

Example 3: the synthetic ammonia is produced by pressure swing adsorption, and after gas transformation, CO₂The content of the carbon dioxide is 20-35 percent, pure hydrogen is separated from the cracked gas by utilizing the methanol to prepare hydrogen through a four-tower PSA production process, the purity of the hydrogen separated by the method can reach 99.9 degrees, a liquid carbon dioxide byproduct is generated, and concentrated CO is extracted from the roasting tail gas generated in the production of alumina by adopting a pressure swing adsorption technology₂Adsorption of large amounts of CO by means of adsorbents₂And a small amount of N₂And O₂Sucking with a vacuum pumpThe tower is effectively vacuumized to desorb the carbon dioxide from the adsorbent with a small amount of nitrogen and oxygen, and then the carbon dioxide is completely extracted, wherein the concentration of the carbon dioxide is more than 35%, and 2x150m is utilized³The coke shaft kiln produces high-activity high-quality lime, carbon dioxide contained in kiln gas is recovered by using three-tower pressure swing adsorption equipment, and before adsorption, first-stage dust removal and second-stage dust removal operations are firstly carried out on the flue gas in the lime kiln, so that the coke shaft kiln has great economic and social benefits and environmental benefits.

Example 4: benefit of

1. Direct economic benefits: the carbon dioxide purified by pressure swing adsorption has high yield and high purity, and not only can realize the reutilization rate of the carbon dioxide, but also can reduce the industrial cost, thereby creating the maximum economic benefit for enterprises and realizing the sustainable development of the enterprises;

2. indirect economic benefits: chemical enterprises such as chemical fertilizer plants and the like can produce urea by using high-purity carbon dioxide extracted by a pressure swing adsorption method as a raw material of a urea device, so that the urea device achieves hundreds of high-load production, the balance problem of ammonia and carbon in industry is solved, and a good foundation is laid for long-period operation of devices such as large chemical fertilizers and the like;

3. social benefits are as follows: the technology for purifying the carbon dioxide by pressure swing adsorption not only fully utilizes the existing resources, but also reduces the emission of the carbon dioxide in greenhouse gases, thereby reducing the environmental pollution to the atmosphere and having better social benefits.

Further, in the above technical solution, in the step S1, the pressure inside the exchange box is set to 130Pa, the temperature is set to 90 ℃, the pressure inside the absorption tower is set to 80Pa, the temperature is set to 120 ℃, and the membrane material is a polyamide membrane, a polysulfone membrane, a cellulose acetate membrane, or a polyether sulfone membrane.

Further, in the above technical solution, in the step S2, the temperature inside the desulfurization tower is set to 110 ℃, the desulfurization time is 2 hours, the temperature inside the dealkylation tower is set to 350 ℃, the dealkylation time is 1.5 hours, and the carbon dioxide moisture removal precision is 0.1x10^-6The residual oxygen content of the deoxidized carbon dioxide is less than0.1x10^-6。

Further, in the above technical solution, in the step S3, the maximum pressure in the pressure changing cylinder is 230Pa, the minimum pressure in the pressure changing cylinder is 80-110Pa, and the number of times of continuously increasing and decreasing the pressure in the pressure changing cylinder is 8-10 times.

Example 5: analysis of impurities

The hydrogen, oxygen, nitrogen, methane and carbon monoxide in the high-purity carbon dioxide are analyzed by adopting a GC9560 pulse discharge helium ionization gas chromatograph with high sensitivity, trace water is analyzed by an electrolytic dew point instrument of the family Mike of America, and a column is cut: silica gel 2m × 3mm, analytical column: 5A molecular sieve 6m × 1.5mm, carrier gas: more than or equal to 99.9999% of ultra-pure helium, a quantitative tube: 0.2ml, detector temperature: 120 ℃, column temperature: 60 ℃, carrier gas flow rate: 30ml/min, helium as balance gas, hydrogen content of 9.97X 10^-6Oxygen 7.17X 10^-69.48X 10 of nitrogen^-6Methane 4.29X 10^-65.59X 10 carbon monoxide^-6The test results of the standard gas are shown in the following table:

according to the analysis result, the purity of the carbon dioxide produced by the process reaches more than 5N through chemical purification and physical purification, and the application in the fields of laser gas preparation, electronic industry, reactor gas coolant, scientific research and the like is completely met.

The points to be finally explained are: first, in the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounted," "connected," and "connected" should be understood broadly, and may be a mechanical connection or an electrical connection, or a communication between two elements, and may be a direct connection, and "upper," "lower," "left," and "right" are only used to indicate a relative positional relationship, and when the absolute position of the object to be described is changed, the relative positional relationship may be changed;

secondly, the method comprises the following steps: only the structures related to the embodiments of the present disclosure are involved, other structures may refer to general designs, and the same embodiment and different embodiments of the present invention may be combined with each other without conflict;

and finally: the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included in the scope of the present invention.