Carbon dioxide deep purification treatment device and method

Abstract

The invention belongs to the technical field of preparation of food-grade carbon dioxide, and relates to a carbon dioxide deep purification treatment device and method. Pressure regulation and impurity rough filtration are carried out on carbon dioxide raw material gas through the pressure regulation and impurity rough filtration unit. And acid gases such as hydrogen sulfide are selectively adsorbed through the desulfurizing tower. And the desulfurized gas is heated to the temperature required by the dealkylation tower through the electric heater. Hydrocarbon impurities are oxidized into harmless substances through the dealkylation tower, so that the product purity is favorably improved. And the high-temperature gas after dealkylation is cooled to below 40 DEG C through the cooling unit, so that the high-temperature gas is prevented from causing thermal damage to a molecular sieve of a subsequent drying tower, and part of water vapor in the carbon dioxide gas after dealkylation is preliminarily removed. And the gas-liquid separation unit is used for separating water from the carbon dioxide. And the drying tower is used for obtaining high-purity dry carbon dioxide. And through real-time detection and multi-parameter synchronous dynamic adjustment of the product detection and regulation system, the purification stability and the carbon dioxide purity are improved, and meanwhile, the energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food-grade carbon dioxide production and relates to a carbon dioxide deep purification treatment device and method. BACKGROUND

[0002] Currently, industrial carbon dioxide treatment is mostly carried out by direct combustion and emission or simple physical adsorption purification.

[0003] Among them, although the direct combustion treatment can recover part of the waste heat, the carbon dioxide is not effectively utilized. For example, the carbon dioxide generated in traditional petroleum refining and thermal power generation industries is usually directly discharged or only subjected to simple combustion treatment, which not only causes resource waste but also aggravates the greenhouse effect.

[0004] The traditional physical adsorption purification can recycle and utilize carbon dioxide, but the traditional physical adsorption purification has the problems of poor selectivity, limited adsorption capacity, high regeneration energy consumption, difficulty in deeply removing impurities such as hydrogen sulfide and hydrocarbons, and difficulty in meeting the food-grade or high-end chemical raw material requirements of the purity of the purified carbon dioxide. At the same time, the existing purification equipment is often single in function and lacks collaborative optimization design, resulting in a long overall purification process, low efficiency, high operation cost, and inability to adapt to large-scale industrial application scenarios.

[0005] In summary, the recycling and utilization of carbon dioxide have the problems of high energy consumption, insufficient recycling purity, insufficient collaborative ability of purification equipment, and low efficiency. SUMMARY

[0006] The purpose of the present application is to provide a carbon dioxide deep purification treatment device and method to solve the technical problem of high energy consumption, insufficient recycling purity, insufficient collaborative ability of purification equipment, and low efficiency in the recycling and utilization of carbon dioxide.

[0007] In order to achieve the above-mentioned purpose, the following technical solutions are adopted in the present application: In a first aspect, the present application provides a carbon dioxide deep purification treatment device, comprising a pressure regulation and impurity rough filtration unit, a desulfurization tower, an electric heater, a dehydrocarbon tower, a cooling unit, a gas-liquid separation unit, a drying tower and a product detection and control system connected in sequence.

[0008] Further, it further comprises a raw material heat exchanger, the inlet of the raw material heat exchanger is connected to the outlet of the dehydrocarbon tower, and the outlet of the raw material heat exchanger is connected to the cooling unit. The connecting pipeline between the pressure regulation and impurity rough filtration unit and the desulfurization tower passes through the raw material heat exchanger. The desulfurization tower is internally provided with a multistage spray absorption layer and a structured packing layer.

[0009] Further, the cooling unit comprises a water cooler and a pre-cooler, and the dehydrocarbon column is connected to the gas-liquid separation unit in sequence through the water cooler and the pre-cooler.

[0010] Further, the gas-liquid separation unit comprises a gas-liquid separator and a coalescer, and the cooling unit is connected to the drying tower in sequence through the gas-liquid separator and the coalescer. The coalescer is internally provided with a coalescing filter element, and the coalescer is provided with an automatic drainage control unit.

[0011] Further, the drying tower comprises a first dryer and a second dryer, and the gas-liquid separation unit is connected to the product detection and regulation system through the first dryer and the second dryer, respectively.

[0012] Further, the first dryer and the second dryer are of the same structure, and the first dryer and the second dryer adopt a double-tower parallel switching regeneration mode, and are both provided with a gas-solid countercurrent contact channel. The first dryer is internally provided with an active alumina layer and a molecular sieve layer in sequence along the airflow direction, the molecular sieve layer is located above the active alumina layer, the active alumina layer is internally provided with active alumina, and the molecular sieve layer is internally filled with molecular sieve.

[0013] Further, the dehydrocarbon column adopts a segmented temperature control type reactor structure, and is internally provided with a plurality of catalyst loading bins along the gas flow direction, and the catalyst loading bins are loaded with catalysts, and the dehydrocarbon column is further internally provided with an oxygen distribution system.

[0014] Further, the product detection and regulation system comprises a gas component analyzer and a central control system, the gas component analyzer is used for real-time monitoring of the purity of carbon dioxide, the hydrogen sulfide content, the hydrocarbon content and the water content of the carbon dioxide discharged by the drying tower, and the central control system is used for adjusting the working parameters of the pressure regulation and impurity rough filtration unit, the desulfurization tower, the electric heater, the dehydrocarbon column, the cooling unit, the gas-liquid separation unit and the drying tower according to the purity of carbon dioxide, the hydrogen sulfide content, the hydrocarbon content and the water content.

[0015] In a second aspect, the present application provides a carbon dioxide deep purification treatment method, comprising the following steps: S1, the pressure of the carbon dioxide raw gas is stabilized in the pressure threshold range through the pressure regulation and impurity rough filtration unit, and the large particle impurities in the gas are removed at the same time; S2, the desulfurization tower is used to remove hydrogen sulfide in the carbon dioxide raw gas, and the desulfurized carbon dioxide gas is obtained; S3, heating the desulfurized carbon dioxide gas to 150-200 DEG C by an electric heater, and feeding the carbon dioxide gas into a hydrocarbon removal tower to remove ethane and hydrocarbon impurities, thereby obtaining hydrocarbon-removed carbon dioxide gas; S4, cooling the hydrocarbon-removed carbon dioxide gas by a cooling unit, and removing part of water vapor in the hydrocarbon-removed carbon dioxide gas, thereby obtaining cooled carbon dioxide gas; S5, drying the cooled carbon dioxide gas by a drying tower, so that the water content of the carbon dioxide is reduced to below 5 ppm; S6, monitoring the purity, hydrogen sulfide content, hydrocarbon content and water content of the carbon dioxide discharged from the drying tower in real time by a product detection and control system, and adjusting the working parameters of the pressure adjustment and impurity rough filtration unit, the desulfurization tower, the electric heater, the hydrocarbon removal tower, the cooling unit, the gas-liquid separation unit and the drying tower according to the purity, hydrogen sulfide content, hydrocarbon content and water content of the carbon dioxide.

[0016] Further, the pressure threshold range is 0.5-0.8 MPa; The gas flow rate of the carbon dioxide raw gas through the desulfurization tower is 0.3-0.5 m / s, and the liquid-gas ratio is 0.8-1.2 L / m 3 3 ; The temperature of the cooled carbon dioxide gas is 5-10 DEG C.

[0017] Compared with the prior art, the present application has the following beneficial effects: The present application adjusts the pressure and removes impurities of the carbon dioxide raw gas by the pressure adjustment and impurity rough filtration unit, removes large-particle impurities, and provides a stable gas source for subsequent purification processes. The desulfurization tower selectively adsorbs acidic gases such as hydrogen sulfide, and the hydrogen sulfide content is reduced to below 0.1 ppm, which is beneficial to improve the product purity. The electric heater heats the desulfurized gas to the required temperature of the hydrocarbon removal tower, which ensures that the hydrocarbon impurities are completely decomposed into carbon dioxide and water under catalytic oxidation conditions. The hydrocarbon removal tower oxidizes the hydrocarbon impurities into harmless substances, which is beneficial to improve the product purity. The cooling unit cools the hydrocarbon-removed high-temperature gas to below 40 DEG C, prevents the high-temperature gas from causing thermal damage to the molecular sieve of the subsequent drying tower, and preliminarily removes part of the water vapor in the hydrocarbon-removed carbon dioxide gas. The gas-liquid separation unit is used to separate water from the carbon dioxide, remove the liquid droplets entrained in the gas, and prevent liquid substances from entering the drying tower to cause the molecular sieve to pulverize. The drying tower is used to further dry the carbon dioxide, and high-purity dried carbon dioxide is obtained. The real-time detection and multi-parameter synchronous dynamic adjustment by the product detection and control system improve the stability of the purification, further improve the carbon dioxide purity, and are beneficial to reduce the energy consumption. The present application significantly improves the carbon dioxide purity by the multi-stage purification steps of "pressure adjustment-desulfurization-hydrocarbon removal-drying".​

[0018] This invention stabilizes the pressure of the carbon dioxide feed gas within a pressure threshold range through a pressure regulation and impurity coarse filtration unit, providing stable gas pressure conditions for subsequent processing steps. Simultaneously, it removes large particulate impurities from the gas, preventing them from entering subsequent processing equipment and ensuring the smooth operation of the subsequent processing flow. A desulfurization tower is used to remove hydrogen sulfide from the carbon dioxide feed gas, effectively reducing its content. An electric heater heats the desulfurized carbon dioxide gas to 150℃~200℃ before it enters a dehydrocarbonation tower. The dehydrocarbonation tower removes ethane and hydrocarbon impurities, yielding dehydrocarbonized carbon dioxide gas. The heating process makes hydrocarbons easier to remove, effectively reducing the hydrocarbon impurity content in the carbon dioxide gas and further improving its purity. A cooling unit cools the dehydrocarbonized carbon dioxide gas, removing some water vapor and creating suitable conditions for subsequent drying, reducing the burden on the drying tower and improving overall purification efficiency. A drying tower dries the cooled carbon dioxide gas, reducing its water content to below 5 ppm, thus improving the quality of the carbon dioxide product. The product testing and control system monitors and adjusts the operating parameters of each unit in real time according to product indicators, ensuring that the entire purification process is always in optimal operating condition, guaranteeing the stable and reliable quality of the final product, and promptly addressing various factors that may affect the purification effect, thereby improving the system's adaptability and stability. This invention gradually removes various impurities such as hydrogen sulfide, hydrocarbons, and water vapor from the carbon dioxide feed gas through desulfurization, dehydrogenation, cooling and dehydration, ultimately achieving a high level of carbon dioxide purity that meets the requirements of food-grade or high-end chemical raw materials. The various processing steps of this invention cooperate with each other, and through reasonable parameter settings and process flow design, unnecessary energy consumption is avoided. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the system connection according to an embodiment of the present invention; Figure 2 This is a flowchart of a method according to an embodiment of the present invention.

[0020] The system includes: 1. Pressure regulation and impurity coarse filtration unit; 2. Desulfurization tower; 3. Electric heater; 4. Hydrocarbon removal tower; 5. Raw material heat exchanger; 6. Water cooler; 7. Precooler; 8. Gas-liquid separator; 9. Coalescer; 10. First dryer; 11. Second dryer; 12. Product detection and control system; 13. Cooling unit; 14. Gas-liquid separation unit; 15. Drying tower. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1This invention discloses a carbon dioxide deep purification treatment device, comprising a pressure regulating and impurity coarse filtration unit 1, a desulfurization tower 2, an electric heater 3, a hydrocarbon removal tower 4, a cooling unit 13, a gas-liquid separation unit 14, a drying tower 15, and a product detection and control system 12 connected in sequence. The pressure regulating and impurity coarse filtration unit 1 regulates the pressure of the carbon dioxide feed gas and performs coarse filtration to remove large particulate impurities, providing a stable gas source for subsequent purification processes. The desulfurization tower 2 selectively adsorbs acidic gases such as hydrogen sulfide, reducing the hydrogen sulfide content to below 0.1 ppm, which helps improve product purity. The electric heater 3 heats the desulfurized gas to the temperature required by the hydrocarbon removal tower, ensuring that hydrocarbon impurities are completely decomposed into carbon dioxide and water under catalytic oxidation conditions. The hydrocarbon removal tower 4 oxidizes hydrocarbon impurities into harmless substances, which helps improve product purity. The cooling unit 13 cools the high-temperature gas after hydrocarbon removal to below 40°C, preventing thermal damage to the molecular sieve in the subsequent drying tower, and simultaneously removing some water vapor from the dehydrogenated carbon dioxide gas. The gas-liquid separation unit 14 is used to separate water from carbon dioxide, remove liquid droplets entrained in the gas, and prevent liquid substances from entering the drying tower and causing molecular sieve pulverization. The drying tower 15 is used to further dry the carbon dioxide to obtain high-purity dried carbon dioxide. The product detection and control system 12 is used to monitor the purity, hydrogen sulfide content, hydrocarbon content, and water content of the carbon dioxide discharged from the drying tower 15 in real time, and adjust the operating parameters of the pressure regulation and impurity coarse filtration unit 1, the desulfurization tower 2, the electric heater 3, the hydrocarbon removal tower 4, the cooling unit 13, the gas-liquid separation unit 14, and the drying tower 15 according to the purity, hydrogen sulfide content, hydrocarbon content, and water content of carbon dioxide.

[0024] This invention significantly improves carbon dioxide purity by employing a multi-stage purification process involving pressure regulation, desulfurization, dehydrocarbonization, and drying, achieving a purity of ≥99% (food grade) to meet the stringent requirements of the high-end chemical and food industries. Real-time monitoring and multi-parameter synchronous dynamic adjustment through the product detection and control system 12 enhances purification stability, further improving carbon dioxide purity while simultaneously reducing energy consumption.

[0025] In this embodiment of the invention, a raw material heat exchanger 5 is also included. The inlet of the raw material heat exchanger 5 is connected to the outlet of the dehydrogenation tower 4, and the outlet of the raw material heat exchanger 5 is connected to the cooling unit 13. The waste heat of the high-temperature gas is recovered through the raw material heat exchanger 5 and used to preheat the pretreated raw material gas, thereby achieving heat recovery.

[0026] The connecting pipeline between the pressure regulation and impurity coarse filtration unit 1 and the desulfurization tower 2 passes through the raw material heat exchanger 5; The desulfurization tower 2 is equipped with a multi-stage spray absorption layer and a structured packing layer.

[0027] In this embodiment of the invention, the cooling unit 13 includes a water cooler 6 and a precooler 7, and the dehydrocarbon removal tower 4 is connected to the gas-liquid separation unit 14 in sequence through the water cooler 6 and the precooler 7.

[0028] In this embodiment of the invention, the gas-liquid separation unit 14 includes a gas-liquid separator 8 and a coalescer 9, and the cooling unit 13 is connected to the drying tower 15 in sequence through the gas-liquid separator 8 and the coalescer 9.

[0029] The coalescer 9 is equipped with a coalescing filter element inside and an automatic drainage control unit.

[0030] In this embodiment of the invention, the drying tower 15 includes a first dryer 10 and a second dryer 11, and the gas-liquid separation unit 14 is connected to the product detection and control system 12 through the first dryer 10 and the second dryer 11 respectively.

[0031] In this embodiment of the invention, the first dryer 10 and the second dryer 11 have the same structure. The first dryer 10 and the second dryer 11 adopt a dual-tower parallel switching regeneration mode. Both the first dryer 10 and the second dryer 11 are provided with a gas-solid countercurrent contact channel. The first dryer 10 has an activated alumina layer and a molecular sieve layer arranged sequentially along the airflow direction inside. The molecular sieve layer is located above the activated alumina layer. The activated alumina layer contains activated alumina, and the molecular sieve layer is filled with molecular sieves.

[0032] In this embodiment of the invention, the dehydrogenation tower 4 adopts a segmented temperature-controlled reactor structure. Several catalyst loading chambers are arranged inside the dehydrogenation tower 4 along the gas flow direction. The catalyst loading chambers are loaded with catalysts. An oxygen distribution system is also provided inside the dehydrogenation tower 4.

[0033] In this embodiment of the invention, the product detection and control system 12 includes a gas composition analyzer and a central control system. The gas composition analyzer is used to monitor in real time the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content, and water content discharged from the drying tower 15. The central control system is used to adjust the operating parameters of the pressure regulation and impurity coarse filtration unit 1, the desulfurization tower 2, the electric heater 3, the dehydrogenation tower 4, the cooling unit 13, the gas-liquid separation unit 14, and the drying tower 15 according to the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content, and water content.

[0034] Based on the above structure, this invention discloses a method for deep purification of carbon dioxide, see [link to relevant documentation]. Figure 2 This includes the following steps: S1 stabilizes the pressure of the carbon dioxide feed gas within the pressure threshold range through the pressure regulation and impurity coarse filtration unit 1, providing stable gas pressure conditions for subsequent processing steps. At the same time, it removes large particulate impurities from the gas, preventing them from entering subsequent processing equipment, avoiding damage such as wear and blockage, extending the service life of the equipment, and ensuring the smooth operation of subsequent processing procedures.

[0035] The pressure threshold range is 0.5MPa to 0.8MPa.

[0036] S2 uses desulfurization tower 2 to remove hydrogen sulfide from the carbon dioxide feed gas, obtaining desulfurized carbon dioxide gas. This effectively reduces the hydrogen sulfide content in the carbon dioxide gas, minimizes the interference of hydrogen sulfide on subsequent equipment and processing, avoids corrosion and other problems that hydrogen sulfide may cause, and provides a purer feed gas for subsequent deep purification treatment.

[0037] The carbon dioxide feed gas flows through desulfurization tower 2 at a velocity of 0.3 m / s to 0.5 m / s, with a liquid-to-gas ratio of 0.8 L / m³. 3 ~1.2L / m 3 ; S3 uses an electric heater 3 to heat the desulfurized carbon dioxide gas to 150℃~200℃ and then it enters the dehydrocarbonization tower 4. The dehydrocarbonization tower 4 removes ethane and hydrocarbon impurities to obtain dehydrocarbonized carbon dioxide gas. The heating process makes the hydrocarbon substances easier to remove. Through the treatment of the dehydrocarbonization tower, the content of hydrocarbon impurities in the carbon dioxide gas can be effectively reduced, and the purity of carbon dioxide can be further improved.

[0038] S4 uses cooling unit 13 to cool the dehydrogenated carbon dioxide gas and remove some water vapor from it, resulting in cooled carbon dioxide gas. During the cooling process, not only can the gas temperature be reduced to create suitable conditions for subsequent drying, but also some water vapor can be removed from the dehydrogenated carbon dioxide gas, reducing the moisture content in the gas, alleviating the burden on the drying tower, and improving the overall purification efficiency.

[0039] The temperature of the cooled carbon dioxide gas is 5℃~10℃; S5 uses drying tower 15 to dry the cooled carbon dioxide gas, reducing the water content of the carbon dioxide to below 5 ppm. After drying, the moisture in the carbon dioxide gas is further removed, meeting the strict requirements of food-grade or high-end chemical raw materials for the purity and water content of carbon dioxide, thus improving the quality of carbon dioxide products.

[0040] S6, the product detection and control system 12 monitors in real time the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content, and water content discharged from the drying tower 15. Based on these parameters, the operating parameters of the pressure regulation and impurity coarse filtration unit 1, the desulfurization tower 2, the electric heater 3, the hydrocarbon removal tower 4, the cooling unit 13, the gas-liquid separation unit 14, and the drying tower 15 are adjusted. This real-time monitoring and control mechanism ensures that the entire purification process is always in optimal operating condition, guarantees the stable and reliable quality of the final product, promptly addresses various factors that may affect the purification effect, and improves the system's adaptability and stability.

[0041] This invention gradually removes various impurities such as hydrogen sulfide, hydrocarbons, and water vapor from carbon dioxide feedstock gas through desulfurization, dehydrogenation, cooling and dehydration, and drying, ultimately achieving a high level of carbon dioxide purity that meets the requirements of food-grade or high-end chemical raw materials, effectively solving the problem of insufficient purity in traditional physical adsorption purification.

[0042] The various processing steps in this invention work together seamlessly, avoiding unnecessary energy consumption through reasonable parameter settings and process flow design. For example, the cooling step removes some water vapor while lowering the gas temperature, creating favorable conditions for the drying step and reducing the energy required for drying. The real-time monitoring and control system adjusts the operating parameters of each unit in a timely manner according to product indicators, avoiding energy waste caused by over-processing or under-processing, and overcoming the high energy consumption problem of traditional methods.

[0043] Example 2: See Figure 1 This embodiment proposes a highly efficient device for deep purification of carbon dioxide by integrating process innovation, equipment optimization and material innovation, including a tower structure and intelligent integrated auxiliary equipment; The tower structure includes: a pressure regulating and impurity coarse filtration unit 1, a desulfurization tower 2, an electric heater 3, a hydrocarbon removal tower 4, a raw material heat exchanger 5, a water cooler 6, a precooler 7, a liquid separator 8, a coalescer 9, a first dryer 10, a second dryer 11, and a product detection and control system 12.

[0044] The desulfurization tower 2, the dehydrocarbon removal tower 4, the first dryer 10, and the second dryer 11 all adopt a modular layered structure design.

[0045] The desulfurization tower 2 is equipped with a multi-stage spray absorption layer and a structured packing layer. By optimizing the gas-liquid contact area and flow rate, the hydrogen sulfide removal efficiency is greatly improved.

[0046] The dehydrocarbon removal tower 4 adopts a segmented temperature-controlled reactor structure, with an independent oxygen distribution system and catalyst loading chamber to ensure that hydrocarbons and oxygen are fully mixed and reacted.

[0047] The first dryer 10 and the second dryer 11 adopt a dual-tower parallel switching regeneration mode. The tower is designed with a unique gas-solid countercurrent contact channel to enhance the mass transfer effect between the desiccant and carbon dioxide gas.

[0048] The intelligent integrated auxiliary equipment includes: coalescer 9 and temperature, pressure, and concentration sensors; The coalescer 9 integrates a high-efficiency coalescing filter element and an automatic drainage control system, which can accurately separate free water; The system is equipped with an intelligent temperature, pressure, and concentration sensor network to monitor the operating parameters of each stage in real time, and automatically adjusts the equipment operating status through a central control system to achieve fully automated and intelligent control of the entire process.

[0049] Based on the above-described apparatus, the present invention provides a method for deep purification of carbon dioxide, see [link to previous document]. Figure 2 This includes the following steps: S1, Carbon dioxide recovery pretreatment: The carbon dioxide feed gas produced by the upstream pressure swing adsorption unit is pressure regulated and impurities are coarsely filtered to remove large particulate impurities and provide a stable gas source for subsequent purification processes.

[0050] S2, Deep Desulfurization Process: A composite desulfurizing agent is used to reduce the hydrogen sulfide content to below 0.1 ppm in the desulfurization tower through a combination of multi-stage spray absorption and packing adsorption. The composite desulfurizing agent is composed of metal oxides and organic amines.

[0051] S3, Catalytic Dehydrocarbonization Process: The dehydrocarbonization process employs segmented heating catalytic combustion technology. Different active catalysts are placed in three sections within the dehydrocarbonization tower. The reaction temperature is precisely controlled based on changes in gas composition, typically ranging from 200℃ to 450℃, achieving a 99.9% conversion rate for ethane and hydrocarbon impurities. Simultaneously, a central control system dynamically adjusts the oxygen supply, ensuring effective dehydrocarbonization while avoiding increased energy consumption and safety risks associated with excessive oxygen.

[0052] S4, High-Efficiency Dehydration and Drying Process: The drying stage employs a two-stage drying process of "activated alumina pre-dehydration + molecular sieve fine dehydration". Activated alumina preferentially adsorbs a large amount of moisture, reducing the load on the molecular sieve; the molecular sieve further dehydrates the water, reducing the water content of carbon dioxide to below 5 ppm. The dryer uses variable temperature and pressure regeneration technology, utilizing the high-temperature purified gas after drying to perform reverse purging of the dryer, reducing regeneration energy consumption by 30% compared to traditional processes.

[0053] S5, Product Gas Quality Control: An online detection and quality control system 12 is set at the purified gas output end to monitor indicators such as carbon dioxide purity and impurity content in real time. When fluctuations in product gas quality are detected, the replenishment amount of desulfurizer, dehydrocarbonizer, and desiccant, as well as process parameters, are automatically adjusted to ensure that product quality is stable and meets standards.

[0054] In summary, the present invention has the following beneficial effects: This invention boasts superior purification performance: through innovative processes and equipment, it achieves a carbon dioxide purity of ≥99% (food grade), meeting the stringent requirements of the high-end chemical and food industries.

[0055] This invention has significant energy-saving and consumption-reducing effects: compared with traditional purification technologies, this technology reduces energy consumption by 40% and operating costs by 35%, and maximizes resource utilization through efficient equipment coordination and process optimization.

[0056] This invention has high reliability and adaptability: the intelligent control system and modular equipment design enable the device to flexibly adjust operating parameters according to different gas source components and production needs, adapting to various industrial scenarios, and the equipment can operate continuously and stably for more than 8,000 hours.

[0057] This invention has significant environmental and economic benefits: the project reduces carbon dioxide emissions by 137,000 tons annually, thereby reducing greenhouse gas emissions; at the same time, it converts carbon dioxide into high-value-added products, creating significant economic benefits for enterprises and promoting green and low-carbon development in the industrial sector.

[0058] Example 3: See Figure 2 This embodiment discloses a method for deep purification of carbon dioxide, as detailed below: S1, carbon dioxide recovery pretreatment; The carbon dioxide feed gas from the upstream pressure swing adsorption (PSA) unit first enters the pressure regulation and coarse filtration stage. Because the feed gas pressure is unstable and may impact downstream equipment, it needs to be stabilized within a suitable range using a pressure regulator, typically adjusted to 0.5 MPa to 0.8 MPa. Simultaneously, coarse filtration equipment, such as a multi-media filter, removes large particulate impurities larger than 5 μm, including rust and dust, providing a stable and clean gas source for subsequent purification processes and preventing impurities from clogging downstream equipment or affecting purification efficiency.

[0059] S2, deep desulfurization process; Pretreated carbon dioxide feed gas enters desulfurization tower 2. Desulfurization tower 2 employs a modular, layered structure, featuring multi-stage spray absorption layers and structured packing layers. The composite desulfurizing agent (composed of metal oxides and organic amines) is sprayed downwards in a uniform, fine mist form through a spray system at the top of the tower, ensuring full contact with the upward-flowing carbon dioxide gas. In the spray absorption layer, hydrogen sulfide rapidly reacts chemically with the active components in the desulfurizing agent, generating sulfide precipitates and other products. In the structured packing layer, the gas-liquid contact area is further increased, and the contact time is prolonged, allowing unreacted hydrogen sulfide to be fully absorbed. By optimizing the gas-liquid contact area and flow rate, the gas velocity is controlled between 0.3 m / s and 0.5 m / s, and the liquid-to-gas ratio is 0.8 L / m³. 3 ~1.2L / m 3 This reduces the hydrogen sulfide content from an initial potential of tens of ppm to below 0.1 ppm, creating favorable conditions for subsequent dehydrocarbonization and dehydration processes.

[0060] S3, an innovative catalytic dehydrocarbonization process; The desulfurized carbon dioxide gas is heated to a suitable temperature by electric heater 3, typically 150℃~200℃, before entering the hydrocarbon removal tower 4. The hydrocarbon removal tower 4 employs a segmented temperature-controlled reactor structure, with catalysts of different activities arranged in three sections along the gas flow direction. When the gas enters the first section, at a lower temperature (approximately 200℃) and under the action of the first-section catalyst, some of the more reactive hydrocarbons begin to undergo catalytic combustion with the added oxygen. As the gas continues to flow, it enters the second section (temperature rises to 300℃~350℃) and the third section (temperature reaches 400℃~450℃). Under the action of the corresponding active catalysts, the remaining ethane and higher hydrocarbon impurities fully react with oxygen to produce carbon dioxide and water. An independent oxygen distribution system ensures that oxygen is evenly dispersed in the gas, while the intelligent control system dynamically adjusts the oxygen supply based on real-time monitoring data of the gas composition. This ensures a hydrocarbon impurity conversion rate of 99.9% while avoiding increased energy consumption and safety hazards caused by excessive oxygen.

[0061] S4, heat exchange cooling and gas-liquid separation; The dehydrocarbonized gas first exchanges heat with the raw material heat exchanger 5, transferring its own heat to the pretreated raw material gas, achieving heat recovery while simultaneously lowering its own temperature. Subsequently, the gas enters the water cooler 6, where it is further cooled to ambient temperature (approximately 40°C) by circulating cooling water. It then passes through the precooler 7, where it is cooled to 5°C–10°C, condensing as much water vapor as possible into liquid water. The cooled gas then enters the gas-liquid separator 8, where gravity settling and inertial separation principles are used to separate most of the free water. Afterward, the gas continues into the coalescer 9, where a high-efficiency coalescing filter element agglomerates tiny water droplets into larger droplets, which are then discharged by an automatic drainage control unit, further reducing the water content in the gas.

[0062] S5, a highly efficient dehydration and drying process; The carbon dioxide gas, after gas-liquid separation and coalescence dehydration, enters the drying tower. The drying tower employs a dual-tower parallel switching regeneration mode. The lower part of the drying tower is filled with activated alumina, and the upper part with molecular sieves. The gas first contacts the activated alumina, which, due to its large specific surface area and excellent water absorption, preferentially adsorbs a large amount of moisture, reducing the load on the subsequent molecular sieves. Next, the gas rises and contacts the molecular sieves, which, utilizing their precise pore size and strong adsorption properties, further dehydrate the gas, reducing the water content of the carbon dioxide to below 5 ppm, meeting the stringent requirements for food-grade carbon dioxide. When the adsorption capacity of the operating drying tower decreases, a valve is switched to initiate regeneration. The high-temperature purified gas after drying is used to counter-purge the regeneration tower (the non-operating drying tower), carrying away the adsorbed moisture. Regeneration energy consumption is reduced by 30% compared to traditional processes. Simultaneously, the standby drying tower is activated to continue dehydration. The temperature of the high-temperature purified gas after drying is approximately 200℃~250℃.

[0063] S6, Product gas quality control; An online detection and quality control system 12 is installed at the purified gas output end. This system is equipped with a high-precision gas composition analyzer, which can monitor the purity of carbon dioxide, hydrogen sulfide, hydrocarbons, moisture and other impurity content in real time. Once a fluctuation in the quality of the product gas is detected, such as a decrease in carbon dioxide purity or an excess of a certain type of impurity, the system immediately feeds the data back to the central control system. The central control system automatically adjusts the replenishment of desulfurizing agent, dehydrocarbonizing agent and desiccant according to the preset control logic, and optimizes process parameters such as electric heater temperature, temperature of each section of the dehydrocarbonizing tower and oxygen replenishment, to ensure that the output purified gas stably meets the food-grade carbon dioxide standard or meets the quality requirements of downstream chemical raw materials, and is ultimately sold as chemical raw material or food-grade carbon dioxide.

[0064] In summary, the beneficial effects of this invention are as follows: This invention pioneers an integrated deep purification process that combines "pretreatment - composite desulfurization - segmented catalytic dehydrocarbonization - two-stage dehydration and drying - intelligent quality control". Through the organic integration of process links and synergistic optimization of parameters, it breaks through the efficiency and purity bottlenecks of traditional purification processes.

[0065] This invention designs modular and intelligent tower bodies and auxiliary equipment, such as layered tower bodies and coalescers with integrated control systems, to enhance equipment functionality and improve operational efficiency, providing hardware support for stable process operation.

[0066] This invention combines composite desulfurizers, high-efficiency catalysts, and optimized desiccants with an intelligent sensor network and a central control system to maximize material performance and achieve precise process control, forming a collaborative innovation system of "materials-equipment-process".

[0067] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A carbon dioxide deep purification treatment device, characterized in that, It includes a pressure regulation and impurity coarse filtration unit (1), a desulfurization tower (2), an electric heater (3), a hydrocarbon removal tower (4), a cooling unit (13), a gas-liquid separation unit (14), a drying tower (15), and a product detection and control system (12), which are connected in sequence.

2. The carbon dioxide deep purification treatment device according to claim 1, characterized in that, It also includes a raw material heat exchanger (5), the inlet of which is connected to the outlet of the dehydrogenation tower (4), and the outlet of which is connected to the cooling unit (13). The connecting pipeline between the pressure regulation and impurity coarse filtration unit (1) and the desulfurization tower (2) passes through the raw material heat exchanger (5). The desulfurization tower (2) is equipped with a multi-stage spray absorption layer and a structured packing layer.

3. The carbon dioxide deep purification treatment device according to claim 1, characterized in that, The cooling unit (13) includes a water cooler (6) and a precooler (7), and the dehydrogenation tower (4) is connected to the gas-liquid separation unit (14) in sequence through the water cooler (6) and the precooler (7).

4. The carbon dioxide deep purification treatment device according to claim 1, characterized in that, The gas-liquid separation unit (14) includes a gas-liquid separator (8) and a coalescer (9), and the cooling unit (13) is connected to the drying tower (15) in sequence through the gas-liquid separator (8) and the coalescer (9). The coalescer (9) is equipped with a coalescing filter element inside, and an automatic drainage control unit is provided on the coalescer (9).

5. The carbon dioxide deep purification treatment device according to claim 1, characterized in that, The drying tower (15) includes a first dryer (10) and a second dryer (11), and the gas-liquid separation unit (14) is connected to the product detection and control system (12) through the first dryer (10) and the second dryer (11).

6. The carbon dioxide deep purification treatment device according to claim 5, characterized in that, The first dryer (10) and the second dryer (11) have the same structure. The first dryer (10) and the second dryer (11) adopt a dual-tower parallel switching regeneration mode. The first dryer (10) and the second dryer (11) are both provided with a gas-solid countercurrent contact channel. The first dryer (10) has an activated alumina layer and a molecular sieve layer arranged sequentially along the airflow direction inside. The molecular sieve layer is located above the activated alumina layer. The activated alumina layer contains activated alumina, and the molecular sieve layer is filled with molecular sieves.

7. The carbon dioxide deep purification treatment device according to claim 1, characterized in that, The dehydrogenation tower (4) adopts a segmented temperature-controlled reactor structure. Several catalyst loading chambers are arranged inside the dehydrogenation tower (4) along the gas flow direction. The catalyst loading chambers are loaded with catalysts. An oxygen distribution system is also provided inside the dehydrogenation tower (4).

8. The carbon dioxide deep purification treatment device according to claim 1, characterized in that, The product testing and control system (12) includes a gas composition analyzer and a central control system. The gas composition analyzer is used to monitor in real time the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content and water content discharged from the drying tower (15). The central control system is used to adjust the working parameters of the pressure regulation and impurity coarse filtration unit (1), the desulfurization tower (2), the electric heater (3), the dehydrogenation tower (4), the cooling unit (13), the gas-liquid separation unit (14) and the drying tower (15) according to the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content and water content.

9. A method for deep purification of carbon dioxide, based on the apparatus according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1, through the pressure regulation and impurity coarse filtration unit (1), stabilizes the pressure of carbon dioxide raw material gas within the pressure threshold range, and removes large particulate impurities in the gas at the same time. S2, using a desulfurization tower (2) to remove hydrogen sulfide from the carbon dioxide raw material gas to obtain desulfurized carbon dioxide gas; S3, the desulfurized carbon dioxide gas is heated to 150℃~200℃ by an electric heater (3) and enters the dehydrogenation tower (4). Ethane and hydrocarbon impurities are removed by the dehydrogenation tower (4) to obtain dehydrogenated carbon dioxide gas; S4, the dehydrogenated carbon dioxide gas is cooled by the cooling unit (13), and some water vapor in the dehydrogenated carbon dioxide gas is removed to obtain cooled carbon dioxide gas; S5, a drying tower (15) is used to dry the cooled carbon dioxide gas, so that the water content of the carbon dioxide is reduced to below 5 ppm; S6, the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content and water content discharged from the drying tower (15) are monitored in real time by the product detection and control system (12), and the working parameters of the pressure regulation and impurity coarse filtration unit (1), the desulfurization tower (2), the electric heater (3), the dehydrogenation tower (4), the cooling unit (13), the gas-liquid separation unit (14) and the drying tower (15) are adjusted according to the purity of carbon dioxide, hydrogen sulfide content, hydrocarbon content and water content.

10. The method for deep purification of carbon dioxide according to claim 9, characterized in that, The pressure threshold range is 0.5 MPa to 0.8 MPa; The carbon dioxide feed gas has a flow velocity of 0.3 m / s to 0.5 m / s through the desulfurization tower (2) and a liquid-to-gas ratio of 0.8 L / m. 3 ~1.2L / m 3 ; The temperature of the cooled carbon dioxide gas is 5℃~10℃.

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