Multi-column combined resolution gas purification device

Abstract

A kind of multi-tower joint analytical gas purification device, belong to raw material gas purification equipment related technical field, including adsorption tower, packing is filled in adsorption tower, for the impurity in raw material gas is adsorbed and purified, adsorption tower is provided with multiple, all adsorption towers are in parallel arrangement;In all adsorption towers, at least one adsorption tower is in analytical working state, at least two adsorption towers are in adsorption working state.Multiple layers of packing are arranged in the adsorption tower and are arranged according to the adsorption order, packing aperture, adsorption strength, analytical condition, multiple different packings are filled separately, and then are filled together in the adsorption tower, the packing layers are isolated.The utility model adopts sealing layer filling, and the packing layers use special sealing separation components, ensure that the packing is not mixed, and it is simple and fast to replace a layer of packing, the utility model is put into use, and the pressure swing adsorption purification device is significantly reduced after one year attenuation rate.

Description

Technical Field

[0001] This utility model belongs to the technical field of raw material gas purification equipment, and more specifically, it relates to a multi-tower combined desorption gas purification device. Background Technology

[0002] Currently, the technologies used for capturing carbon dioxide from power plant boiler flue gas are PSA (Pressure Swing Adsorption) and ammonia absorption. The tail gas after carbon dioxide capture is either directly discharged or reused after simple filtration. This tail gas contains a large amount of aerosols and other toxic and harmful components. The emission of these components pollutes the atmosphere, and their reuse can cause significant pollution and poisoning to the core separation materials in downstream utilization and purification units.

[0003] The current technology involves using physical cooling combined with multi-stage physical filtration to physically filter particulate matter with a diameter of 1-5 micrometers in the exhaust gas before reuse. The technical problems with this method are: it cannot remove toxic and harmful pollutants with a diameter of nanometers. These aerosol toxic and harmful pollutants will adhere to the core separation material during exhaust gas utilization and purification, causing the separation material to become poisoned and the separation efficiency to drop sharply. As a result, the technical indicators of the product gas fail to meet the standards, the product gas volume decreases, and the product gas purity decreases. Utility Model Content

[0004] (I) Technical Issues

[0005] In conclusion, how to pre-purify the raw material gas to improve the quality of the product gas has become a problem that urgently needs to be solved by those skilled in the art.

[0006] (II) Technical Solution

[0007] This utility model provides a multi-tower combined desorption gas purification device. In this utility model, the multi-tower combined desorption gas purification device includes an adsorption tower. The adsorption tower is filled with packing material for adsorbing and purifying impurities in the raw gas. Multiple adsorption towers are provided, and all the adsorption towers are arranged in parallel.

[0008] In all of the adsorption towers, at least one adsorption tower is in the desorption operation state, and at least two adsorption towers are in the adsorption operation state.

[0009] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, one end of the adsorption tower is provided with a first gas port, and two parallel branches are provided on the first gas port, namely the first branch and the second branch; the other end of the adsorption tower is provided with a second gas port, and two parallel branches are provided on the second gas port, namely the third branch and the fourth branch; wherein, in all the adsorption towers shown, the first branch is connected through an adsorption outlet pipe, the third branch is connected through an adsorption inlet pipe, the second branch is connected through a desorption inlet pipe, and the fourth branch is connected through a desorption outlet pipe.

[0010] Preferably, the multi-tower combined desorption gas purification device provided by this utility model further includes a raw material gas delivery pipe, which is connected to the adsorption gas inlet pipe and the desorption gas inlet pipe, and can supply gas to the adsorption gas inlet pipe or the desorption gas inlet pipe separately by controlling the valve.

[0011] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, each of the branches is equipped with a valve that can be controlled individually.

[0012] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, the valve installed on the third branch is a proportional regulating valve, and the other valves are all on / off valves.

[0013] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, all the adsorption towers are arranged vertically.

[0014] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, the adsorption tower is filled with multiple packing layers along the gas flow path, and the packing in each packing layer can be replaced individually.

[0015] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, a sealing separation component is provided between each of the packing layers to separate the packing layers during filling.

[0016] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, the particle size and pore size of the packing material in each of the packing layers are different.

[0017] Preferably, in the multi-tower combined desorption gas purification device provided by this utility model, an airflow diffuser is provided inside the adsorption tower and near both ends of the adsorption tower.

[0018] (III) Beneficial Effects

[0019] As can be seen from the above, this utility model provides a multi-tower combined desorption gas purification device. In this utility model, the multi-tower combined desorption gas purification device includes an adsorption tower, which is filled with packing material for adsorbing and purifying impurities in the raw gas. Multiple adsorption towers are provided, and all the adsorption towers are arranged in parallel. Among all the adsorption towers, at least one adsorption tower is in the desorption working state, and at least two adsorption towers are in the adsorption working state.

[0020] In this utility model, the specific structure of the adsorption tower and the arrangement of the adsorption tower are designed as follows:

[0021] 1. The adsorption tower is equipped with multiple layers of packing. The packing is arranged in a variety of different ways according to the adsorption sequence, packing pore size, adsorption intensity and desorption. The different packings are filled separately and then filled together in the adsorption tower, and the packing layers are isolated from each other.

[0022] 2. Employing multi-tower combined operation with diverse working modes. This utility model adopts sealed layer filling, and uses a dedicated sealing and separation component between the packing layers to ensure that the packing materials are not mixed. Replacing a certain layer of packing material is simple and quick. In actual use, if one type of packing material cannot be desorbed and regenerated after adsorption, this type of packing material can be replaced separately, while other packing materials can continue to be used.

[0023] After this utility model was put into use, it worked continuously in a mixed working mode. Compared with before the adsorption purification device was used, the increase in the proportion of elements was significantly reduced, with the increase in proportion being less than 2%. The annual attenuation rate of the pressure swing adsorption purification device was significantly reduced. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the adsorption tower in a multi-tower combined desorption gas purification device according to one embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of a multi-tower combined desorption gas purification device in one embodiment of the utility model.

[0026] exist Figure 1 and Figure 2 In the diagram, the correspondence between component names and reference numerals is as follows:

[0027] 1. Adsorption tower; 2. Sealed separation assembly; 3. Packing material; 4. Raw material gas delivery pipe; 5. Adsorption gas inlet pipe; 6. Desorption gas inlet pipe; 7. Proportional regulating valve. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0029] Please refer to Figure 1 and Figure 2 ,in, Figure 1 This is a schematic diagram of the adsorption tower in a multi-tower combined desorption gas purification device according to one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a multi-tower combined desorption gas purification device in one embodiment of the utility model.

[0030] This invention provides a multi-tower combined gas purification device. The process of this device is described as follows: The main components of the boiler flue gas after passing through the carbon dioxide capture device are nitrogen (89%), oxygen (8%), carbon dioxide (3%), and a small amount of impurities. First, after cooling and physical filtration by a three-stage filter to remove impurities, the gas enters the pressure swing adsorption (PSA) purification device. Then, the PSA purification device separates the oxygen and carbon dioxide in the gas source, obtaining high-purity nitrogen of 99.9%. This invention uses a cooling + physical filtration method to remove large particulate impurities with a particle size of 1-3 micrometers, meeting the working conditions of the PSA nitrogen purification equipment.

[0031] However, the above process also has certain technical problems: after 1-2 years of long-term operation of the pressure swing adsorption (PSA) nitrogen purification equipment, it was found that the production volume and purity of the 99.9% pure nitrogen product gas both decreased, and the decrease rate was much higher than the normal decrease rate of 3-5% / year. In multiple devices, the highest decrease rate even reached 21%, while the rest were between 17-20%, and energy consumption also increased by 20-23%.

[0032] After encountering the aforementioned problems, troubleshooting was conducted. Repeated inspections revealed no electrical or mechanical faults in the pressure swing adsorption (PSA) nitrogen purification unit itself. Further analysis suggested that the poisoning of packing material 3 might be caused by abnormal gas source components. Multiple routine on-site gas bag sampling, testing, and analysis revealed the absence of gas components commonly causing packing material 3 poisoning (such as chlorine or oil). Further sampling and testing of the gas source for sulfides and nitrogen oxides revealed levels below 0.1 ppm for both sulfides and nitrogen oxides, insufficient to cause short-term poisoning of the separation packing material. Further sampling and testing of the gas source for methane, propane, and n-butane showed levels below 0.1 ppm, indicating these were not the primary causes of poisoning.

[0033] After turning on the pressure swing adsorption (PSA) nitrogen purification unit, samples were taken from the packing material. No obvious changes were observed in appearance, but elemental analysis revealed the presence of new elements. Further analysis of samples taken from different bed heights and different working cycles showed that all packing materials tested contained new elements. Comparative analysis revealed a pattern in the increase of elements in packing material 3: the element amount gradually decreased from the bottom to the top layer, and the element amount gradually decreased from long to short working cycles. After multiple analyses and discussions, it was concluded that the source of the new elements was the gas source, which contained compounds in the form of these new elements.

[0034] A self-made absorption testing device was used, employing purified water or other absorbents. A stable flow of gas was passed through the device to detect substances added to the absorbent. The mass content was calculated by combining the gas flow rate and absorption time. The following impurities were identified in the gas source:

[0035]

[0036]

[0037] A comparative experiment was conducted using magnets to attract samples and new fillers. The new fillers showed no magnetism, while all the sampled fillers were magnetic, with the strength of the magnetism changing in a regular pattern: the magnetism gradually decreased from the bottom layer to the top layer, and the magnetism gradually decreased from a long working cycle to a short working cycle.

[0038] After identifying the problem, the following solutions were attempted: Testing revealed that impurities in the gas source affected the performance and lifespan of the separation packing material. Filtering was then performed to remove these impurities. Based on the existing cooling and multi-stage filtration system, the cooling device was improved to further reduce the temperature from 35℃ to 25℃. After one week of monitoring, no increase in the aforementioned impurities was observed in the discharged wastewater. The temperature was further reduced from 25℃ to 8℃, and after another week of monitoring, no increase in impurities was found in the discharged wastewater. This cooling temperature reached the limit of conventional cooling and pressure swing adsorption, making further cooling attempts impossible. The possibility of separation and precipitation at low temperatures was ruled out.

[0039] Two additional filtration stages were added to the existing equipment, increasing the filtration precision to 0.01 microns and 0.003 microns respectively. Used in conjunction with a cooling temperature of 8°C, monitoring after one week of operation revealed no increase in impurities in the filter discharge. A self-made activated carbon adsorption tower (Standard 1) was added, filled with columnar granular activated carbon with an iodine value of over 1000 for adsorption filtration. Monitoring after one week of operation revealed no increase in impurities in the discharge from any of the filters or activated carbon adsorption tower 1. A self-made strong magnetic filter was installed at the outlet of the 5-micron filter to attempt to remove divalent and trivalent iron from the impurities. After four weeks of operation, the strong magnetic filter's cover was opened, and no visible residue was found around the strong magnet. The strong magnetic filter was placed at the outlet of the self-made activated carbon adsorption tower 1, and after four weeks of operation, the strong magnetic filter's cover was opened, and no visible residue was found around the strong magnet. In conclusion: the impurities do not possess pure magnetism and cannot be directly attracted by a magnet; the impurities cannot be removed by a physical filter with a 0.003-micron filtration precision, and the impurity particle size is <0.003 microns.

[0040] Based on experience gained from multiple trials, the particle size of the impurities was calculated to be <0.003 micrometers. Considering the characteristics of this gas source composition (nitrogen (89%), oxygen (8%), and carbon dioxide (3%)), a conventional adsorption dryer was attempted. An additional 180Nm dryer was added. 3A micro-thermal regeneration adsorption dryer with a throughput of [ / min] and a pressure dew point of -40℃ was installed after the cooling device and a 0.01-micron filter. Before commissioning, samples of the adsorption dryer packing material 3 were taken and sealed. After stable operation, the dew point remained at -62℃, with slight fluctuations to -60℃ during dual-tower switching. Monitoring was conducted for one, two, and four weeks, recording the discharge ports of each filter stage, the cooling device, and the activated carbon adsorption tower 1. No impurities were found in the discharged materials. No visible residue was observed around the strong magnetic filter. The adsorption dryer operated stably with a stable dew point curve and was operating normally without faults. Monitoring continued for three months, and the equipment remained stable with a stable dew point curve and was operating normally without faults. After six months of stable operation with consistent dew point, samples 1 and 2 of the top and bottom packing materials were taken from the loading and unloading ports after shutdown and compared with the sealed sample 3. The results showed that while some elements in samples 1, 2, and 3 increased, the increase was minimal, less than 0.5%, and the difference between samples 1 and 2 was less than 0.1%. Therefore, the following conclusions can be drawn: 1. Impurities cannot be adsorbed by the packing material 3 in a conventional adsorption dryer; 2. After adsorption, they are precipitated after high-temperature, low-pressure purging. Because the adsorption dryer operates with both adsorption and desorption processes, the above two conclusions cannot be accurately confirmed. Therefore, the dryer was adjusted as follows: the dryer only performs low-temperature adsorption and does not perform high-temperature regeneration desorption; the dew point of the gas source after dryer treatment is no longer monitored. After four months of operation, samples 4 and 5 were taken from the top and bottom packing 3 for testing. After comparing the test reports of samples 1 and 2, the increase in elemental content of samples 4 / 5 was less than 0.5% compared to samples 1 / 2, and the difference between samples 4 and 5 was less than 0.1%. It can be determined that the impurities cannot be adsorbed by the packing 3 of the conventional adsorption dryer.

[0041] From the discovery of the degradation until the last technical upgrade attempt mentioned above, a year had passed. During this period, the equipment was in a state of continuous degradation, with an average degradation rate of 17.4% per year calculated cumulatively.

[0042] Phase Summary and Analysis: The adsorption characteristics of the pressure swing adsorption (PSA) purification unit's separation packing are such that the packing preferentially adsorbs oxygen and carbon dioxide, while nitrogen passes through the packing to achieve the separation of oxygen, carbon dioxide, and nitrogen, concentrating the target nitrogen gas to over 99.9%. This results in a product gas flow and purity reduction rate as high as 20%, far exceeding the normal production reduction rate of 3-5% / year, and an increase in energy consumption of 20-23%. The main reason is that impurities or impurity compounds enter the PSA purification unit with the gas source, adhere to the surface of the separation packing, and, with repeated pressure increases and decreases, enter the micropores of the packing, causing pore blockage. These impurities cannot be discharged through normal desorption steps, resulting in pore poisoning of the separation packing, disrupting its polarity, and rapidly reducing the separation efficiency of oxygen, nitrogen, and carbon dioxide (annual reduction rate as high as 17-20%). This leads to substandard final product nitrogen flow and purity, and significantly increases equipment energy consumption (energy consumption increase of 20-23%). Poisoned packing cannot be removed through conventional industrial desorption; therefore, factory activation techniques can be attempted to improve the packing's performance. Sample 730 kg (sample 6) was taken from one of the machines with the largest attenuation (Unit 3) and sent to the company. 330 kg of this sample was randomly loaded into the experimental apparatus. Oxygen and nitrogen were separated using air as the feed gas, and the separation efficiency and gas consumption were recorded. A mixture of 92% pure nitrogen and 8% pure oxygen produced by the gas generation platform was used as the feed gas for oxygen and nitrogen separation, and the separation efficiency and gas consumption were recorded. After confirming the quantity was correct, the 330 kg of packing material was removed from the experimental apparatus and mixed with the remaining sample 6, dividing it into two batches: 360 kg each for samples 7 and 8. The remaining 10 kg was designated as sample 9, which was then activated and regenerated under different processes. The activation and regeneration conditions for sample 7 were: activation temperature 350℃, activation time 3 hours, and activation environment with nitrogen purging and slight positive pressure; the activation and regeneration conditions for sample 8 were: activation temperature 500℃, activation time 3 hours, and activation environment with nitrogen purging and slight positive pressure; the activation and regeneration conditions for sample 9 were: activation temperature 500℃, activation time 5 hours, and activation environment with vacuum negative pressure -50kPa (gauge pressure). The loss rates after activation were 5%, 5.3%, and 5.8%, respectively. After activation, samples 7 and 8 were loaded and subjected to air and mixed gas separation tests, respectively. Sample 9 underwent static adsorption. The changes in performance indicators compared to before activation were as follows:

[0043] Sample Name Performance growth rate Gas consumption reduction rate Sample 7 -13.8％ +12.7％ Sample 8 -14.2％ +13.5％ Sample 9 -12.6％ +11.3％

[0044] A negative performance growth rate indicates a further decrease in separation efficiency; a positive gas consumption reduction rate indicates a further increase in energy consumption. All three samples showed a further decrease in performance after activation, the opposite of the activation and regeneration effect of similar packing materials, and the difference was significant. In other similar projects, similar separation packing materials, after activation and regeneration (under the same conditions as sample 7), showed performance improvements of 75-85% of the performance of brand-new packing materials. The basic principle of activation and regeneration is to vaporize contaminants adhering to the surface or micropores of the packing material at high temperatures, and then use inert gas to purge and replace the precipitated contaminants (or use vacuum negative pressure). This is a direct and effective technique for most contaminants. However, for samples 7 / 8 / 9, not only did the efficiency not improve but it actually decreased, suggesting that the contaminants reacted with the packing material at high temperatures, further exacerbating the pore-clogging and poisoning phenomenon. Therefore, elemental analysis of the activated packing material was unnecessary.

[0045] Interim summary: After technical modification experiments including activation and regeneration, cooling, multi-stage filtration, and conventional adsorption dryer, no effect was achieved. Based on the recorded experimental results, it was deduced that the particle size of the impurities and pollutants is <5 nanometers, and they are prone to chemical reaction with the packing material at high temperatures. Even when using the blocking method for regeneration, heating desorption regeneration cannot be used.

[0046] Based on the problem-solving analysis of the above-mentioned multiple stages, this utility model proposes to adopt a newly designed multi-tower adsorption equipment for gas source purification. The equipment is named a multi-tower combined desorption gas purification device. The design concept is as follows: it adopts a combination of various packing materials with large, medium, and small pore sizes for adsorption purification and desorption regeneration. Desorption regeneration does not use heating but room temperature desorption regeneration. Packing material isolation is used between various packing layers. If it is found that desorption regeneration cannot be completed after adsorption purification, this part of the packing material can be replaced periodically to prevent impurities from entering the subsequent pressure swing adsorption purification system. In the desorption regeneration design, it is considered that the desorbed gas source enters the next adsorption tower 1 for utilization and cannot be directly vented, which would waste a large amount of tower gas and purging gas, and is defined as zero gas consumption. If zero gas consumption adsorption purification cannot be achieved, low gas consumption adsorption purification can be used. A small amount of gas is discharged from the tower after adsorption, and the desorption regeneration gas is directly discharged into the atmosphere. The discharge volume is adjustable and defined as low gas consumption, with the gas consumption not exceeding 3%. The design must comprehensively consider the feasibility of switching between the two adsorption purification processes and the mixed application of the two adsorption purification processes. The pore size, strength, and adsorption capacity of the packing material for gas source and impurities must be comprehensively considered. The structural design should maximize the adsorption capacity. An innovative three-tower adsorption structure is proposed to ensure simultaneous adsorption purification in two towers and desorption and regeneration in one tower. A reasonable internal tower structure is required. With a large gas source volume and high pressure, reasonable airflow distribution is needed to control the empty tower velocity and improve the service life of the packing material. A bottom airflow diffuser and a top airflow collector are proposed for uniform diffusion and collection at 6 points. Finite element simulation analysis of the structure has been used. Inert alumina is uniformly filled on the bottom airflow diffuser to avoid direct contact with the packing material and avoid causing significant impact on the packing material. When switching between multiple towers, pressure drop and reversal need to be considered to reduce the number of airflow reversals in the tower and reduce the pressure drop after airflow reversal. Isobaric reversal or reversal after pressure equalization is proposed. Manual sampling and venting ports are provided in the tower body and pipelines.

[0047] This utility model provides a multi-tower combined desorption gas purification device, including an adsorption tower 1, which is a tank structure (using a metal tank structure). Along the length direction of the adsorption tower 1 (which can also be understood as along the gas flow path inside the adsorption tower 1), a first gas port is provided at one end of the adsorption tower 1, and a second gas port is provided at the other end of the adsorption tower 1. The first gas port and the second gas port are used for gas inlet and gas outlet, respectively.

[0048] The structure of adsorption tower 1 is as follows: Adsorption tower 1 is filled with packing material 3 for adsorbing and purifying impurities in the raw gas. Multiple adsorption towers 1 are provided, and all adsorption towers 1 are connected in parallel. Among all adsorption towers 1, at least one adsorption tower 1 is in the desorption working state, and at least two adsorption towers 1 are in the adsorption working state. Specifically, one end of adsorption tower 1 is provided with a first gas port, and two parallel branches are provided on the first gas port, namely the first branch and the second branch. The other end of adsorption tower 1 is provided with a second gas port, and two parallel branches are provided on the second gas port, namely the third branch and the fourth branch. Among all the adsorption towers 1 shown, the first branch is connected through the adsorption outlet pipeline, the third branch is connected through the adsorption inlet pipeline 5, the second branch is connected through the desorption inlet pipeline 6, and the fourth branch is connected through the desorption outlet pipeline.

[0049] This invention also includes a raw material gas delivery pipe 4, which is connected to the adsorption gas inlet pipe 5 and the desorption gas inlet pipe 6. Gas can be supplied to the adsorption gas inlet pipe 5 or the desorption gas inlet pipe 6 separately via control valves. To achieve control of the gas path, each branch is equipped with an individually controllable valve. Furthermore, the valve on the third branch is a proportional regulating valve 7, while the other valves are on / off valves.

[0050] Inside the adsorption tower 1 and along the gas flow path, the adsorption tower 1 is filled with multiple packing layers, and the packing material 3 in each packing layer can be replaced individually; a sealing separation component 2 is provided between each packing layer to separate the packing layers; and the particle size and pore size of the packing material 3 in each packing layer are different. At the same time, airflow diffusers are provided inside the adsorption tower 1 and near both ends of the adsorption tower 1.

[0051] In the above structural design, the raw gas enters the adsorption tower 1 from the bottom, then passes through each packing layer sequentially (from bottom to top), and finally exits from the top, thereby achieving adsorption and purification of the raw gas. In the desorption process, the raw gas, as the purge gas, enters the adsorption tower 1 from the top, then passes through each packing layer sequentially (from top to bottom), thereby achieving desorption and restoration of each packing layer.

[0052] Regarding the specific structure of the adsorption tower 1, this invention provides a sealing separation assembly 2 within the tower body of the adsorption tower 1. Multiple sealing separation assemblies 2 are provided, all of which are located within the adsorption tower 1. Within the adsorption tower 1 and along the gas flow path, the sealing separation assembly 2 divides the internal space of the adsorption tower 1 into multiple cavity structures. This invention also provides packing material 3 within the adsorption tower 1. Depending on the adsorption sequence, pore size, adsorption intensity, and desorption conditions, the packing material 3 includes various types and is respectively filled into different cavity structures.

[0053] An internal support structure is installed inside the adsorption tower 1. The sealing separation component 2 adopts a metal frame and metal mesh structure, with the mesh size smaller than the particle size of the packing material 3 in this layer. This ensures the smooth passage of the raw gas while stably supporting the packing material 3. Alternatively, the sealing separation component 2 can be a cage-like structure, completely filling the packing material 3 within it for easy replacement. It is important to note that the sealing separation component 2 maintains a completely airtight contact with the inner wall of the tower to prevent the escape of the raw gas.

[0054] In this invention, a first packing layer is formed by packing 3, which is filled into the first cavity structure within the adsorption tower 1 and along the gas flow path. The first packing layer is composed of macroporous spherical adsorption packing with a diameter of 3-5 mm, a strength of 150 N, and a bulk density of 750 kg / m³. 3 With a pore size of 5 nanometers, it is used to adsorb water and carbon dioxide in the mixed gas source. After adsorption by this packing layer, the dew point can be reduced to -60℃ and the carbon dioxide concentration can be reduced to 2.8%.

[0055] In this invention, a second packing layer is formed by packing 3, which is filled into a second cavity structure within the adsorption tower 1 and along the gas flow path. The second packing layer is composed of medium-pore spherical adsorption packing with a diameter of 3-5 mm, a strength of 80 N, and a bulk density of 720 kg / m³. 3 With a pore size of 0.4-0.5 nanometers, it is used to improve the adsorption of impurities and compounds. The total content of impurities and compounds in the gas after adsorption by the second packing layer is <10 μg / m³. 3 .

[0056] In this invention, a third packing layer is formed by packing 3, which is filled into a third cavity structure within the adsorption tower 1 along the gas flow path. The third packing layer is a small-pore granular adsorption packing with a diameter of 1.0-1.3 mm, a strength of 65 N, and a bulk density of 700 kg / m³. 3 With a pore size of 0.3-0.4 nm, it is used to adsorb residual 10 μg / m 3 Impurities and compounds.

[0057] Specifically, each packing layer in the adsorption tower 1 can be analyzed and replaced individually.

[0058] As described above, multiple adsorption towers 1 are provided, and all adsorption towers 1 are connected in parallel. At least three adsorption towers 1 are provided, and among all the adsorption towers 1 shown, at least one adsorption tower 1 is in the desorption working state, and at least two adsorption towers 1 are in the adsorption working state. Furthermore, the number of adsorption towers 1 in the adsorption working state is at least twice the number of adsorption towers 1 in the desorption working state. Simultaneously, all adsorption towers 1 in this invention include two working modes: zero gas consumption mode and low gas consumption mode. In the zero gas consumption mode, no raw material gas is vented, while in the low gas consumption mode, the raw material gas is vented, with a venting rate of 3%, i.e., a 3% gas loss. Furthermore, the multi-tower combined desorption gas purification device adopts a mixed working mode of zero gas consumption and low gas consumption. The zero gas consumption mode operates for 3-4 hours, the low gas consumption mode operates for 1-2 hours, and the total switching time is 4-6 hours. The working process can be appropriately increased or decreased depending on the working state.

[0059] If the hybrid process is not applicable, then the low-gas-consumption process shall be used alone.

[0060] Based on the aforementioned experience, this utility model proposes a new solution, as follows:

[0061] 1. Improvements to the composite packing layer:

[0062] The packing material 3 is divided into three different types according to the adsorption sequence, pore size, adsorption strength, and desorption characteristics. These three types of packing material are mixed and packed (specifically, each layer is filled with the same type of packing material, and then each layer is packed into the interior of the adsorption tower 1) in the adsorption tower 1, with isolation between the packing layers. The first packing layer is a large-pore spherical adsorption packing material 3 with a diameter of 3-5 mm, a strength of 150 N, and a bulk density of 750 kg / m³. 3 The first layer has a pore size of 5 nanometers and strong impact resistance. Its main function is to adsorb small amounts of water and trace amounts of carbon dioxide in the mixed gas source. After adsorption by this packing layer, the dew point can be reduced to -60℃ and the carbon dioxide concentration can be reduced to 2.8%. The second packing layer is a medium-pore spherical adsorption packing 3 with a diameter of 3-5 mm, a strength of 80 N, and a bulk density of 720 kg / m³. 3 The pore size is 0.4-0.5 nanometers. The adsorption filler 3 with this pore size exhibits strong adsorption for impurities and compounds and can be regenerated. The total content of impurities and compounds after adsorption by the second filler layer is <10 μg / m³. 3 The third packing layer is a small-pore granular adsorption packing 3 with a diameter of 1.0-1.3 mm, a strength of 65 N, and a bulk density of 700 kg / m³. 3 With a pore size of 0.3-0.4 nm, its main function is to adsorb residual 10 μg / m³. 3Impurities and compounds. The total content of impurities and compounds after passing through the three-layer packing material is <4 μg / m³. 3 Note: The above data are derived from multiple experiments and are theoretical calculations.

[0063] Through the above structural design, this utility model has the following advantages:

[0064] 1. Packing material 3 is easy to replace.

[0065] The packing is sealed and a dedicated sealing and separation component 2 is used between the packing layers to ensure that the packing 3 is not mixed. Replacing a certain packing layer 3 is simple and quick. In actual use, if one type of packing 3 cannot be desorbed and regenerated after adsorption, this type of packing 3 can be replaced separately while the other packing 3 can continue to be used.

[0066] 2. Diverse processes.

[0067] The workflow is diversified, with the main workflows being zero-gas-consumption and low-gas-consumption. The two workflows are planned to be used in combination during operation. If the process monitoring data deviates significantly from the design data, the workflow can be adjusted at any time. For the zero-gas-consumption mode, the three-tower process mainly involves the following steps: Tower 3 desorption, Tower 1 adsorption, Tower 2 adsorption; Tower 1 desorption, Tower 2 adsorption, Tower 3 adsorption; Tower 2 desorption, Tower 3 adsorption, Tower 1 adsorption. During adsorption, two towers adsorb simultaneously, while one tower regenerates. Compared to one tower adsorption and one tower regeneration, the adsorption capacity is doubled, equivalent to doubling the processed gas volume. The desorption and regeneration towers have zero emissions and do not consume any raw material gas. For the low-gas-consumption mode, the three-tower process mainly involves the following steps: Tower 1 adsorption, Tower 2 adsorption, Tower 3 desorption; Tower 2 adsorption, Tower 3 adsorption, Tower 1 desorption; Tower 3 adsorption, Tower 1 adsorption, Tower 2 desorption. In dual-tower adsorption, the third tower undergoes desorption and regeneration, with the desorbed gas vented. The venting rate is adjustable, designed to be 3%, meaning a 3% gas loss. During adsorption, both towers adsorb simultaneously while one tower regenerates. Compared to a single-tower adsorption and single-tower regeneration system, this doubles the adsorption capacity, effectively doubling the gas throughput.

[0068] The workflow is designed to combine zero-gas-consumption and low-gas-consumption processes. The zero-gas-consumption process takes 3-4 hours, the low-gas-consumption process takes 1-2 hours, and the total switching time is 4-6 hours. The workflow can be adjusted according to the working conditions. If the hybrid process is not suitable, the low-gas-consumption process can be used alone.

[0069] 3. Actual results.

[0070] After the equipment was put into operation, it was continuously monitored using a mixed process for 12 months. Sampling was conducted from the 26th to the 28th of each month, with monitoring points at the bottom of adsorption tower 1 (sludge discharge) and the finished gas outlet. A self-made absorption testing device was used for testing, and the results showed that the total content of impurities and compounds was 4-8 μg / m³.3 After 11 months of operation, samples were taken from the packing material 3 of the pressure swing adsorption (PSA) purification unit for analysis. Compared with before the adsorption purification unit was used, the increase in element content was significantly reduced, with an increase of less than 2%. The annual attenuation rate of the PSA purification unit was 5.2%, slightly higher than the average attenuation rate of 3-5% per year. According to the data, the multi-tower combined gas desorption purification unit has a significant effect and is an effective product.

[0071] As is known from common technical knowledge, this utility model can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

Claims

1. A multi-tower combined desorption gas purification device, characterized in that, It includes an adsorption tower, which is filled with packing material for adsorbing and purifying impurities in the raw gas. Multiple adsorption towers are provided, and all of the adsorption towers are connected in parallel. In all of the adsorption towers, at least one adsorption tower is in the desorption operation state, and at least two adsorption towers are in the adsorption operation state.

2. The multi-tower combined desorption gas purification device according to claim 1, characterized in that, One end of the adsorption tower is provided with a first gas port, and two parallel branches are provided on the first gas port, namely the first branch and the second branch. The other end of the adsorption tower is provided with a second gas port, and two parallel branches are provided on the second gas port, namely the third branch and the fourth branch. In all of the adsorption towers shown, the first branch is connected through an adsorption outlet pipeline, the third branch is connected through an adsorption inlet pipeline, the second branch is connected through a desorption inlet pipeline, and the fourth branch is connected through a desorption outlet pipeline.

3. The multi-tower combined desorption gas purification device according to claim 2, characterized in that, It also includes a raw material gas delivery pipe, which is connected to the adsorption gas inlet pipe and the desorption gas inlet pipe, and can supply gas to the adsorption gas inlet pipe or the desorption gas inlet pipe separately by controlling the valve.

4. The multi-tower combined desorption gas purification device according to claim 3, characterized in that, Each of the aforementioned branches is equipped with a valve that can be controlled individually.

5. The multi-tower combined desorption gas purification device according to claim 4, characterized in that, The valve installed on the third branch is a proportional regulating valve, while the other valves are on / off valves.

6. The multi-tower combined desorption gas purification device according to claim 1, characterized in that, All of the aforementioned adsorption towers are installed vertically.

7. The multi-tower combined desorption gas purification device according to claim 1, characterized in that, Inside the adsorption tower and along the gas flow path, the adsorption tower is filled with multiple packing layers, and the packing material in each packing layer can be replaced individually.

8. The multi-tower combined desorption gas purification device according to claim 7, characterized in that, A sealing and separating component is provided between each of the packing layers to separate the packing layers during filling.

9. The multi-tower combined desorption gas purification device according to claim 8, characterized in that, The particle size and pore size of the filler in each of the aforementioned filler layers are different.

10. The multi-tower combined desorption gas purification device according to claim 9, characterized in that, An airflow diffuser is provided inside the adsorption tower and near both ends of the adsorption tower.

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