A temperature-swing adsorption gas purification system and purification process

Abstract

The present invention discloses a variable temperature adsorption gas purification system and purification process, including a raw material air intake main pipe, an adsorption purification device, a product gas discharge main pipe, a regeneration heater, a regeneration vacuum pump, and a regeneration liquid separation tank. When the device is operated according to the control system, the adsorbent regeneration method is vacuum negative pressure regeneration. After the vacuum negative pressure regeneration runs for several months, when the device control index shows an upward trend, it switches to variable temperature flushing regeneration. After one variable temperature flushing regeneration, vacuum negative pressure regeneration is performed for several months until the next variable temperature flushing regeneration, and the regeneration is cyclically regenerated. The use of this cyclic regeneration method can save the consumption of regeneration gas and steam and circulating cooling water required for the variable temperature flushing regeneration; the overall investment of the device will be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature-swing adsorption tower and adsorbent regeneration, and in particular to a temperature-swing adsorption gas purification system and purification process. Background Art

[0002] Temperature swing adsorption is mainly used to remove trace impurity components that are not easy to desorb at normal temperature and pressure after adsorption. The adsorbent regeneration is carried out at normal pressure and high temperature. The regeneration is divided into two steps: high-temperature flushing regeneration and low-temperature flushing regeneration. The regeneration gas source is generally the product gas purified by temperature swing adsorption or other gases from outside the boundary area that do not contain the removed impurities and have no effect on the adsorbent performance. During high-temperature flushing regeneration, the regeneration gas source is heated by steam through the heater, and then the bed is heated from top to bottom through the adsorption tower to the required temperature, so that the adsorbed impurities are desorbed at high temperature. During low-temperature flushing regeneration, the bed is flushed from top to bottom through the adsorption tower with normal temperature regeneration gas to normal temperature. Because the vaporization of the adsorbed water and the heating of the adsorption bed during high-temperature flushing regeneration require a lot of heat, and the regeneration gas flow rate is fixed, the temperature swing adsorption regeneration time is generally long (about 10 hours), which also makes the adsorption time longer, resulting in a large amount of adsorbent loading, increased equipment weight, and a relatively large overall investment in the device.

[0003] When the adsorbent is regenerated by high-temperature flushing (the maximum regeneration temperature is about 220°C), the performance of the adsorbent functional groups is affected. As the number of high-temperature flushing and regeneration increases, the adsorbent performance will decay to a certain extent, affecting the service life of the adsorbent and the performance indicators of purified gas.

[0004] The temperature of the regenerated exhaust gas after regeneration is 40-220°C, and it needs to be cooled to ~50°C by a cooler before leaving the boundary area, consuming a large amount of circulating cooling water.

[0005] The existing regeneration process has the following problems:

[0006] ① Temperature swing adsorption regeneration requires a large amount of regeneration gas, and the consumption of steam and cooling water is also large, resulting in high operating costs.

[0007] ② The long regeneration time (the total time for high-temperature flushing regeneration and low-temperature flushing regeneration is about 10 hours) leads to a large amount of adsorbent loading, which also increases the weight of the adsorption tower equipment and the total investment of the device is relatively large.

[0008] ③ Frequent high-temperature flushing and regeneration cause the adsorbent performance to decay significantly, affecting the adsorbent service life and device performance indicators. Or in order to solve the problem caused by the attenuation of adsorbent performance, it is necessary to increase the amount of adsorbent, thereby increasing the device investment.

[0009] ④ When the product gas purified by the device is used as the regeneration gas source, the processing load of the device needs to be increased, thereby increasing investment and consumption. Summary of the invention

[0010] The object of the present invention is to provide a temperature-swing adsorption gas purification system and purification process.

[0011] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0012] The temperature-variable adsorption gas purification system of the present invention comprises a raw material air inlet main pipe, an adsorption purification device, a product gas exhaust main pipe, a regeneration heater, a regeneration vacuum pump, and a regeneration liquid separator tank. The adsorption purification device is divided into multiple groups, and the inlet pipe of each group of the adsorption purification devices is connected in parallel with the raw material air inlet main pipe, and the outlet pipe of each group of the adsorption purification devices is connected in parallel with the product gas exhaust main pipe. The inlet pipe of the adsorption purification device is connected to the inlet of the regeneration vacuum pump through a group of parallel branch pipes, and the inlet pipe of the adsorption purification device is connected to the inlet of the step-down regulating valve through another group of branch pipes. The outlet of the step-down regulating valve and the outlet of the regeneration vacuum pump are both connected to the inlet of the regeneration liquid separator tank. The outlet of the regeneration liquid separator tank is a vacuum desorption air outlet main pipe. The outlet pipe of the adsorption purification device is connected to the outlet of the regeneration heater and the outlet of the eighth program-controlled valve at the same time through a group of branch pipes. The inlet of the regeneration heater is connected to the outlet of the ninth program-controlled valve, and the inlets of the eighth program-controlled valve and the ninth program-controlled valve are both connected to the high-temperature flushing regeneration air inlet main pipe.

[0013] One end of a booster pipe is connected to the pipeline of the product gas discharge main pipe, a booster regulating valve is provided in the middle section of the booster pipe, and the other end of the booster pipe is connected in parallel with another group of branch pipes provided on the outlet pipe of the adsorption purification device.

[0014] The inlet pipe of the adsorption purification device is connected to the high-temperature flushing regeneration gas outlet main pipe through another set of parallel branch pipes.

[0015] The adsorption purification device is composed of a raw material inlet branch pipe, an adsorption tower, a product gas discharge branch pipe, a third branch pipe, a fourth branch pipe, a first outlet branch pipe, a second outlet branch pipe, a third outlet branch pipe, a first program-controlled valve, a second program-controlled valve, a third program-controlled valve, a fourth program-controlled valve, a fifth program-controlled valve, a sixth program-controlled valve, and a seventh program-controlled valve. One end of the raw material inlet branch pipe is connected in parallel with the raw material inlet main pipe through the first program-controlled valve, and the other end of the raw material inlet branch pipe is connected to the inlet of the adsorption tower. The pipe wall of the raw material inlet branch pipe is respectively connected to one end of the first outlet branch pipe, the second outlet branch pipe, and the third outlet branch pipe. The other ends of the first outlet branch pipe, the second outlet branch pipe, and the third outlet branch pipe are connected in parallel with the first outlet branch pipe, the second outlet branch pipe, and the third outlet branch pipe of another group of the adsorption purification device. The terminal of the first outlet branch pipe, the second outlet branch pipe, and the third outlet branch pipe are connected in parallel. The fifth program-controlled valve, the sixth program-controlled valve and the seventh program-controlled valve are respectively connected in series, one end of the product gas discharge branch pipe is connected to the outlet of the adsorption tower, the other end of the product gas discharge branch pipe is connected to one end of the second program-controlled valve, the other end of the second program-controlled valve is connected to the product gas discharge main pipe, the pipe wall of the product gas discharge branch pipe is connected to one end of the third branch pipe and the fourth branch pipe respectively, the other ends of the third branch pipe and the fourth branch pipe are connected in parallel with the third branch pipe and the fourth branch pipe of another group of the adsorption purification device, the third program-controlled valve and the fourth program-controlled valve are connected in series on the middle sections of the third branch pipe and the fourth branch pipe, the third outlet branch pipe is connected to the high-temperature flushing regeneration outlet main pipe, the second outlet branch pipe is connected to the inlet of the regeneration vacuum pump, the first outlet branch pipe is connected to the inlet of the step-down regulating valve, the fourth branch pipe is connected to the eighth program-controlled valve and the regeneration heater, and the third branch pipe is connected to the boost regulating valve.

[0016] The present invention discloses a temperature-variable adsorption gas purification process, which includes a vacuum negative pressure regeneration process and a temperature-variable flushing regeneration process. The vacuum negative pressure regeneration process includes the following steps:

[0017] ① Adsorption: The raw gas enters the adsorption tower through the first program-controlled valve, and the impurity components therein are sequentially adsorbed by the various adsorbents loaded in the adsorption tower, and the obtained purified product gas is discharged through the second program-controlled valve. As the adsorption proceeds, when the front edge of the impurity rises to a height close to the adsorption bed, the first program-controlled valve and the second program-controlled valve are closed to stop the adsorption;

[0018] ② Reverse release: After the adsorption process is completed, the adsorption front of the adsorption tower has basically reached the bed outlet. At this time, the fifth program-controlled valve is opened to reduce the pressure of the adsorption tower to normal pressure in the opposite direction of adsorption. At this time, a small part of the adsorbed impurity components begin to desorb from the adsorbent. The reverse release desorbed gas enters the regeneration liquid separator after being regulated by the pressure reduction regulating valve, and then enters the gas pipeline network together with the vacuum desorbed gas;

[0019] When the adsorption pressure is low or the regeneration pressure is close to the adsorption pressure, this process step ② is not required;

[0020] ③ Vacuum negative pressure regeneration: After the reverse discharge is completed, open the sixth programmable valve and use the regeneration vacuum pump to vacuum desorb the adsorption bed. At this time, the impurities adsorbed by the adsorbent are desorbed under negative pressure to complete the regeneration of the adsorbent. After the vacuum regeneration gas passes through the regeneration separator, it enters the gas pipeline network together with the reverse discharge desorption gas;

[0021] ④ Pressurization: After the vacuum negative pressure desorption is completed, open the third program-controlled valve, and slowly pressurize the adsorption tower to the adsorption pressure through the boost regulating valve to pass the purified product gas in the opposite direction of adsorption, and then the adsorption tower will enter the next adsorption process;

[0022] When step ② is absent, process step ④ is not required;

[0023] Multiple adsorption towers alternately carry out the above adsorption and regeneration process to achieve continuous purification of the raw gas;

[0024] The variable temperature flushing regeneration process comprises the following steps:

[0025] ⑤ Cut off the adsorption tower: When the adsorption tower completes negative pressure regeneration, the control system will cut off the adsorption tower to isolate the adsorption tower from other adsorption towers in the system to prepare for variable temperature flushing regeneration. At this time, other adsorption towers except this adsorption tower are still operated in vacuum negative pressure regeneration mode;

[0026] ⑥ High-temperature flushing regeneration: Open the ninth program-controlled valve, the fourth program-controlled valve, and the seventh program-controlled valve. The regeneration gas from outside the boundary area is heated to about 240°C by the regeneration heater and then passes through the adsorption tower from top to bottom. The bed layer of the adsorption tower is flushed to the required temperature at high temperature, and the high-temperature flushing desorption gas enters the flare gas network;

[0027] High-temperature flushing regeneration: the gas temperature at the outlet of the adsorption tower regeneration is maintained at 40°C at the beginning, and when it gradually rises to ≥150°C, step ⑥ is completed;

[0028] ⑦ Constant temperature flushing regeneration: When the outlet temperature of the adsorption tower for high-temperature flushing regeneration reaches the required temperature, the high temperature flushing process is continuously maintained to fully regenerate the adsorbent, i.e. constant temperature flushing. The constant temperature is controlled at 150-220℃ according to the different desorbed substances;

[0029] ⑧ Low-temperature flushing and regeneration: After the constant temperature flushing is completed, the adsorption tower is flushed at low temperature. At this time, the ninth programmable valve is closed, and the eighth programmable valve, the fourth programmable valve, and the seventh programmable valve are opened to allow the low-temperature flushing gas with a temperature of ≤40℃ to enter the adsorption tower from top to bottom, and the bed layer of the adsorption tower is flushed at low temperature to the required temperature. The regenerated desorption gas enters the flare gas network;

[0030] Low-temperature flushing regeneration: the gas temperature at the outlet of the adsorption tower regeneration is basically maintained at ≥150°C in the initial stage, and when it gradually and slowly drops to ≤45°C, step⑧ is completed;

[0031] ⑨ Put the adsorption tower into operation: After the low-temperature flushing and regeneration is completed, close all the programmable valves connected to the cut-off adsorption tower, and put the adsorption tower into operation through the control system. At this point, the adsorption tower completes a variable temperature flushing and regeneration process.

[0032] The beneficial effects of the present invention are:

[0033] The present invention is a temperature-swing adsorption gas purification system and purification process. Compared with the prior art, the present invention has the following effects:

[0034] ① When the device is running, the adsorbent regeneration method is vacuum negative pressure regeneration. After a few months of vacuum negative pressure regeneration, when the device control index shows an upward trend, it will switch to variable temperature flushing regeneration. After a variable temperature flushing regeneration, vacuum negative pressure regeneration will be carried out for several months until the next variable temperature flushing regeneration, and the regeneration cycle will be repeated. The use of this cyclic regeneration method can save the consumption of regeneration gas and steam and circulating cooling water required for the variable temperature flushing regeneration. Taking the processing capacity of 60000Nm 3 / h coke oven gas purification as an example, it can save 6000Nm per hour 3 Regeneration gas, about 3 tons of medium-pressure steam and about 30 tons of circulating cooling water. The operating cost is greatly reduced and the economic benefits are obvious.

[0035] ② Since the impurities to be removed from the raw gas are trace amounts, the total amount of impurities to be removed is also small. When vacuum negative pressure desorption is used, the vacuum pump requires a small amount of air to be pumped. The vacuum pumping time of a tower is controlled within a few hours. In this way, the vacuum negative pressure desorption time is only about 40% of the variable temperature flushing regeneration desorption time. The vacuum negative pressure desorption process adsorbent loading can be reduced to about 70% of the adsorbent dosage required for variable temperature flushing regeneration. With the reduction of adsorbent dosage, the adsorption tower equipment will also be reduced, and the overall investment of the device will be greatly reduced.

[0036] ③ Since variable temperature flushing and regeneration is carried out only once every few months, the attenuation of adsorbent performance caused by high-temperature flushing and regeneration is effectively slowed down, the service life of the adsorbent and the performance indicators of the device are effectively guaranteed, and the amount of adsorbent can be appropriately reduced, thereby reducing the investment in the device.

[0037] ④ When the purified product gas is used as the regeneration gas source, the vacuum negative pressure regeneration process can reduce the design load of the device by 10% compared with the variable temperature flushing regeneration process, which can save the raw gas flow and increase the yield of effective gas, while reducing the overall investment of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of the present invention.

[0039] In the figure: 1-raw material air inlet main pipe, 2-adsorption purification device, 3-product gas discharge main pipe, 4-regeneration heater, 5-regeneration vacuum pump, 6-regeneration liquid separation tank, 7-boosting pipe, 8-raw material air inlet branch pipe, 9-adsorption tower, 10-product gas discharge branch pipe, 11-third branch pipe, 12-fourth branch pipe, 13-first air outlet branch pipe, 14-second air outlet branch pipe, 15-third air outlet branch pipe, 16-high temperature flushing regeneration air inlet main pipe, 17-vacuum desorption air outlet main pipe, 18-high temperature flushing regeneration air outlet main pipe. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0041] like Figure 1 As shown: the present invention comprises a raw material air intake pipe 1, an adsorption purification device 2, a product gas exhaust pipe 3, a regeneration heater 4, a regeneration vacuum pump 5, and a regeneration liquid separator 6. The adsorption purification device 2 is a plurality of groups, and the inlet pipe of each group of the adsorption purification device 2 is connected in parallel with the raw material air intake pipe 1, and the outlet pipe of each group of the adsorption purification device 2 is connected in parallel with the product gas exhaust pipe 3. The inlet pipe of the adsorption purification device 2 is connected to the inlet of the regeneration vacuum pump 5 through a group of parallel branch pipes, and the inlet pipe of the adsorption purification device 2 is connected to the inlet of the regeneration vacuum pump 5 through another group of branch pipes. The pipeline is connected to the inlet of the step-down regulating valve V11, the outlet of the step-down regulating valve V11 and the outlet of the regeneration vacuum pump 5 are both connected to the inlet of the regeneration liquid separator tank 6, the outlet of the regeneration liquid separator tank 6 is the vacuum desorption gas outlet main pipe 17, the outlet pipeline of the adsorption purification device 2 is connected to the outlet of the regeneration heater 4 and the outlet of the eighth program-controlled valve V8 at the same time through a group of branch pipelines, the inlet of the regeneration heater 4 is connected to the outlet of the ninth program-controlled valve V9, and the inlets of the eighth program-controlled valve V8 and the ninth program-controlled valve V9 are both connected to the high-temperature flushing regeneration air intake main pipe 16.

[0042] One end of a booster pipe 7 is connected to the pipeline of the product gas discharge main pipe 3, a booster regulating valve V10 is provided in the middle section of the booster pipe 7, and the other end of the booster pipe 7 is connected in parallel with another group of branch pipes provided on the outlet pipe of the adsorption purification device 2.

[0043] The inlet pipe of the adsorption purification device 2 is connected to the high-temperature flushing regeneration gas outlet main pipe 18 through another set of parallel branch pipes.

[0044] The adsorption purification device 2 is composed of a raw material air intake branch pipe 8, an adsorption tower 9, a product gas discharge branch pipe 10, a third branch pipe 11, a fourth branch pipe 12, a first air outlet branch pipe 13, a second air outlet branch pipe 14, a third air outlet branch pipe 15, a first program-controlled valve V1A, a second program-controlled valve V2A, a third program-controlled valve V3A, a fourth program-controlled valve V4A, a fifth program-controlled valve V5A, a sixth program-controlled valve V6A, and a seventh program-controlled valve V7A. One end of the raw material air intake branch pipe 8 is connected in parallel with the raw material air intake main pipe 1 through the first program-controlled valve V1A. The other end of the gas branch pipe 8 is connected to the inlet of the adsorption tower 9, and the pipe wall of the raw material inlet branch pipe 8 is connected to one end of the first gas outlet branch pipe 13, the second gas outlet branch pipe 14 and the third gas outlet branch pipe 15 respectively, and the other ends of the first gas outlet branch pipe 13, the second gas outlet branch pipe 14 and the third gas outlet branch pipe 15 are connected in parallel with the first gas outlet branch pipe 13, the second gas outlet branch pipe 14 and the third gas outlet branch pipe 15 of another group of the adsorption purification device 2, and the terminal of the first gas outlet branch pipe 13, the second gas outlet branch pipe 14 and the third gas outlet branch pipe 15 is connected to the first gas outlet branch pipe 13, the second gas outlet branch pipe 14 and the third gas outlet branch pipe 15. The fifth program-controlled valve V5A, the sixth program-controlled valve V6A and the seventh program-controlled valve V7A are connected in series respectively, one end of the product gas discharge branch pipe 10 is connected to the outlet of the adsorption tower 9, the other end of the product gas discharge branch pipe 10 is connected to one end of the second program-controlled valve V2A, the other end of the second program-controlled valve V2A is connected to the product gas discharge main pipe 3, the pipe wall of the product gas discharge branch pipe 10 is connected to one end of the third branch pipe 11 and the fourth branch pipe 12 respectively, the other end of the third branch pipe 11 and the fourth branch pipe 12 are connected to another group of the adsorption purification The third branch pipe 11 and the fourth branch pipe 12 of the device 2 are connected in parallel, the third programmable valve V3A and the fourth programmable valve V4A are connected in series on the middle sections of the third branch pipe 11 and the fourth branch pipe 12, the third air outlet branch pipe 15 is connected to the high-temperature flushing regeneration air outlet main pipe 18, the second air outlet branch pipe 14 is connected to the inlet of the regeneration vacuum pump 5, the first air outlet branch pipe 13 is connected to the inlet of the step-down regulating valve V11, the fourth branch pipe 12 is connected to the eighth programmable valve V8 and the regeneration heater 4, and the third branch pipe 11 is connected to the boost regulating valve V10.

[0045] The specific working principle of the recycling process of the present invention is as follows:

[0046] The entire process of the main flow is now described by taking the adsorption tower 9 as an example. The working processes of the adsorption towers 9 in the multiple adsorption purification devices 2 are exactly the same.

[0047] 1. Vacuum negative pressure regeneration process:

[0048] Vacuum negative pressure regeneration is to regenerate the adsorbent by desorbing the adsorbed impurities from the adsorbent, which is based on the principle that the adsorbent's adsorption capacity for impurities is significantly weakened under negative pressure. This process requires the use of power equipment. For the desorption effect of removing trace impurities with strong adsorption capacity: the vacuum negative pressure regeneration effect is stronger than the normal pressure flushing regeneration effect but weaker than the variable temperature flushing regeneration effect. Therefore, under this working condition, the adsorbent needs to be regenerated by variable temperature flushing after several months of vacuum negative pressure regeneration to enhance the regeneration effect.

[0049] When the adsorbent is put into operation for the first time or after temperature-changing flushing and regeneration, it can be put into vacuum negative pressure regeneration. The process is as follows:

[0050] 1 Adsorption:

[0051] The raw gas enters the adsorption tower 9 through the first program-controlled valve V1A, and the impurity components therein are sequentially adsorbed by the various adsorbents loaded in the adsorption tower 9, and the obtained purified product gas is discharged through the second program-controlled valve V2A. As the adsorption proceeds, when the front of the impurity (i.e., the adsorption front) rises to a certain height close to the adsorption bed, the first program-controlled valve V1A and the second program-controlled valve V2A are closed to stop the adsorption.

[0052] 2 Reverse

[0053] After the adsorption process is completed, the adsorption front of the adsorption tower 9 has basically reached the bed outlet. At this time, the fifth program-controlled valve V5A is opened to reduce the pressure of the adsorption tower 9 to normal pressure in the opposite direction of adsorption. At this time, a small part of the adsorbed impurity components begin to be desorbed from the adsorbent. The reverse desorbed gas is regulated by the pressure-reducing regulating valve V11 and enters the regeneration liquid separation tank, and then enters the gas pipeline network together with the vacuum desorbed gas.

[0054] When the adsorption pressure is low (such as coal gas purification, the adsorption pressure is about 10KPa) or the regeneration pressure is close to the adsorption pressure, this process step is not required.

[0055] 3. Vacuum negative pressure regeneration:

[0056] After the reverse release is completed, open the sixth programmable valve V6A and use the regeneration vacuum pump to vacuum desorb the adsorption bed. At this time, the impurities adsorbed by the adsorbent are desorbed under negative pressure, completing the regeneration of the adsorbent. After the vacuum regeneration gas passes through the regeneration separator, it enters the gas pipeline together with the reverse release desorption gas.

[0057] 4 Boost:

[0058] After the vacuum negative pressure desorption is completed, the third program-controlled valve V3A is opened, and the purified product gas is slowly pressurized to the adsorption pressure in the opposite direction of the adsorption through the boost regulating valve V10, and then the adsorption tower enters the next adsorption process.

[0059] When there is no reverse step sequence, i.e. step 2, this process step is not required.

[0060] By alternately carrying out the above adsorption and regeneration processes on four adsorption towers, continuous purification of the raw gas can be achieved.

[0061] 2. Variable temperature flushing regeneration process

[0062] Variable temperature flushing regeneration includes three main process steps: high temperature flushing regeneration, constant temperature flushing regeneration, and low temperature flushing regeneration.

[0063] Variable temperature flushing regeneration is divided into two aspects: heating up the bed and flushing. The principle is to utilize the fact that the adsorbent's adsorption capacity for adsorbed impurities is weakened at higher temperatures. At the same time, the adsorbed impurity content in the regeneration gas is low, while the concentration of adsorbed impurities in the adsorbent micropores and gaps is high. When the regeneration gas passes through the adsorption bed during the top-down flushing process, the adsorbed impurities are transferred from high concentration to low concentration, so that the adsorbent is desorbed and regenerated.

[0064] After the adsorption tower 9 has been operated in a vacuum negative pressure regeneration mode for several months, when the device control index shows an upward trend, it is necessary to perform temperature-variable flushing regeneration. The process is as follows:

[0065] 1. Remove the adsorption tower

[0066] When adsorption tower 9 completes negative pressure regeneration, it is cut off in the control system to isolate adsorption tower 9 from other adsorption towers in the system in preparation for temperature-variable flushing regeneration. At this time, other adsorption towers except adsorption tower 9 are still operated in vacuum negative pressure regeneration mode.

[0067] 2 High temperature flushing regeneration

[0068] Open the ninth program-controlled valve V9, the fourth program-controlled valve V4A, and the seventh program-controlled valve V7A. The regeneration gas from outside the boundary area (the purified product gas in the device system can also be used as the regeneration gas source) is heated to about 240°C by the regeneration heater and then passes through the adsorption tower from top to bottom, and the bed layer of the adsorption tower is high-temperature flushed to the required temperature. The high-temperature flushing desorption gas enters the flare gas network. Because this process is to regenerate the adsorption tower after cutting it off, the amount of regeneration gas and steam can be reduced by extending the high-temperature flushing time, which usually takes several days.

[0069] In high-temperature flushing regeneration, the gas temperature at the outlet of the adsorption tower regeneration is basically maintained at 40°C in the initial stage, and this step is terminated when the temperature gradually rises to ≥150°C.

[0070] 3 Constant temperature flushing regeneration

[0071] When the outlet temperature of the adsorption tower reaches the required temperature, the high temperature flushing process is continued to ensure that the adsorbent is fully regenerated, i.e. constant temperature flushing. The constant temperature is controlled at 150-220℃ according to the different desorbed substances, and the constant temperature flushing time is about several hours.

[0072] 4Low temperature flushing and regeneration

[0073] After the constant temperature flushing is completed, the adsorption tower is flushed at low temperature. At this time, the ninth program-controlled valve V9 is closed, and the eighth program-controlled valve V8, the fourth program-controlled valve V4A, and the seventh program-controlled valve V7A are opened to allow the low-temperature flushing gas with a temperature of ≤40°C to enter the adsorption tower from top to bottom, and the bed layer of the adsorption tower is flushed at low temperature to the required temperature, and the regenerated desorption gas enters the flare gas network. Because this process regenerates the adsorption tower after cutting it off, the amount of regenerated gas and cooling water can be reduced by extending the low-temperature flushing time, which usually takes several days.

[0074] Low-temperature flushing regeneration: the gas temperature at the outlet of the adsorption tower regeneration is basically maintained at ≥150°C in the initial stage, and this step is terminated when it is gradually and slowly cooled to ≤45°C.

[0075] 5. Put into adsorption tower

[0076] After the low-temperature flushing and regeneration is completed, all program-controlled valves of the adsorption tower 9 are closed, and the adsorption tower 9 is put into operation in the control system. At this point, the adsorption tower 9 completes a variable temperature flushing and regeneration process.

[0077] The adsorption tower 9 then operates in a vacuum negative pressure mode for regeneration, and after a few months, when the device control index shows an upward trend again, the next temperature-changing flushing regeneration is performed. In this way, the vacuum negative pressure regeneration and temperature-changing flushing regeneration are continuously cycled to complete the entire regeneration process of the adsorption bed, so it is called a cyclic regeneration process.

[0078] In the device for removing trace impurities in raw gas by temperature-variable adsorption, the single negative pressure regeneration method, the negative pressure regeneration and temperature-variable flushing regeneration in series or in parallel or the regeneration method of cyclic switching all belong to this cyclic regeneration process.

[0079] The above embodiment is only one of the preferred implementation methods of the recycling process and should not be used to limit the protection scope of the recycling process. Any changes or modifications that are made to the main design concept and spirit of the recycling process and have no substantive significance, and the technical problems they solve are still consistent with the recycling process, should be included in the protection scope of the recycling process.

[0080] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A temperature swing adsorption gas purification system, Features: The invention comprises a raw material air intake pipe (1), an adsorption purification device (2), a product gas exhaust pipe (3), a regeneration heater (4), a regeneration vacuum pump (5), and a regeneration liquid separation tank (6). The adsorption purification device (2) is divided into three groups. The inlet pipe of each group of the adsorption purification devices (2) is connected in parallel with the raw material air intake pipe (1), the outlet pipe of each group of the adsorption purification devices (2) is connected in parallel with the product gas exhaust pipe (3), the inlet pipe of the adsorption purification device (2) is connected to the inlet of the regeneration vacuum pump (5) through a group of parallel branch pipes, and the inlet pipe of the adsorption purification device (2) is connected to the outlet of the regeneration vacuum pump (5) through another group of branch pipes. The inlet of the pressure reducing regulating valve (V11) is connected, the outlet of the pressure reducing regulating valve (V11) and the outlet of the regeneration vacuum pump (5) are both connected to the inlet of the regeneration liquid separator (6), the outlet of the regeneration liquid separator (6) is a vacuum desorption gas outlet pipe (17), the outlet pipe of the adsorption purification device (2) is simultaneously connected to the outlet of the regeneration heater (4) and the outlet of the eighth program-controlled valve (V8) through a group of branch pipes, the inlet of the regeneration heater (4) is connected to the outlet of the ninth program-controlled valve (V9), and the inlets of the eighth program-controlled valve (V8) and the ninth program-controlled valve (V9) are both connected to the high-temperature flushing regeneration air inlet pipe (16); The adsorption purification device (2) comprises a raw material air intake branch pipe (8), an adsorption tower (9), a product gas discharge branch pipe (10), a third branch pipe (11), a fourth branch pipe (12), a first air outlet branch pipe (13), a second air outlet branch pipe (14), a third air outlet branch pipe (15), a first program-controlled valve (V1A), a second program-controlled valve (V2A), a third program-controlled valve (V3A), a fourth program-controlled valve (V4A), a fifth program-controlled valve (V5A), a sixth program-controlled valve (V6A), and a seventh program-controlled valve (V7A). One end of the raw material air intake branch pipe (8) is connected in parallel to the raw material air intake main pipe (1) via the first program-controlled valve (V1A). The other end of the raw material inlet branch pipe (8) is connected to the inlet of the adsorption tower (9); the tube wall of the raw material inlet branch pipe (8) is respectively connected to one end of the first outlet branch pipe (13), the second outlet branch pipe (14) and the third outlet branch pipe (15); the other ends of the first outlet branch pipe (13), the second outlet branch pipe (14) and the third outlet branch pipe (15) are connected in parallel to the first outlet branch pipe (13), the second outlet branch pipe (14) and the third outlet branch pipe (15) of another group of the adsorption purification device (2); the first outlet branch pipe (13), the second outlet branch pipe (14) and the third outlet branch pipe (15) are connected to the adsorption tower (9); The terminals are respectively connected in series with the fifth program-controlled valve (V5A), the sixth program-controlled valve (V6A) and the seventh program-controlled valve (V7A); one end of the product gas discharge branch pipe (10) is connected to the outlet of the adsorption tower (9); the other end of the product gas discharge branch pipe (10) is connected to one end of the second program-controlled valve (V2A); the other end of the second program-controlled valve (V2A) is connected to the product gas discharge main pipe (3); the pipe wall of the product gas discharge branch pipe (10) is respectively connected to one end of the third branch pipe (11) and the fourth branch pipe (12); the other ends of the third branch pipe (11) and the fourth branch pipe (12) are connected to another group of the adsorption purification devices ( 2) are connected in parallel with the third branch pipe (11) and the fourth branch pipe (12), the third programmable valve (V3A) and the fourth programmable valve (V4A) are connected in series on the middle sections of the third branch pipe (11) and the fourth branch pipe (12), the third outlet branch pipe (15) is connected to the high-temperature flushing regeneration outlet main pipe (18), the second outlet branch pipe (14) is connected to the inlet of the regeneration vacuum pump (5), the first outlet branch pipe (13) is connected to the inlet of the step-down regulating valve (V11), the fourth branch pipe (12) is connected to the eighth programmable valve (V8) and the regeneration heater (4), and the third branch pipe (11) is connected to the step-up regulating valve (V10).

2. The temperature swing adsorption gas purification system according to claim 1, Features: One end of a booster pipe (7) is connected to the pipeline of the product gas discharge main pipe (3), a booster regulating valve (V10) is provided in the middle section of the booster pipe (7), and the other end of the booster pipe (7) is connected in parallel to another group of branch pipes provided on the outlet pipeline of the adsorption purification device (2).

3. The temperature swing adsorption gas purification system according to claim 1, Features: The inlet pipe of the adsorption purification device (2) is connected to the high-temperature flushing regeneration gas outlet main pipe (18) via another set of parallel branch pipes.

4. A temperature swing adsorption gas purification process based on the temperature swing adsorption gas purification system according to any one of claims 1 to 3, Features: It includes a vacuum negative pressure regeneration process and a variable temperature flushing regeneration process, and the vacuum negative pressure regeneration process includes the following steps: ① Adsorption: the raw gas enters the adsorption tower (9) through the first program-controlled valve (V1A), and the impurity components therein are sequentially adsorbed by the various adsorbents loaded in the adsorption tower (9), and the obtained purified product gas is discharged through the second program-controlled valve (V2A). As the adsorption proceeds, when the front of the impurity rises to a height close to the adsorption bed, the first program-controlled valve (V1A) and the second program-controlled valve (V2A) are closed to stop the adsorption; ② Reverse release: After the adsorption process is completed, the adsorption front of the adsorption tower (9) has basically reached the bed outlet. At this time, the fifth programmable valve (V5A) is opened to reduce the pressure of the adsorption tower (9) to normal pressure in the opposite direction of the adsorption. At this time, a small part of the adsorbed impurity components begins to be desorbed from the adsorbent. The reverse release desorbed gas is regulated by the pressure reduction regulating valve (V11) and enters the regeneration separator tank, and then enters the gas pipeline together with the vacuum desorbed gas; ③ Vacuum negative pressure regeneration: After the reverse discharge is completed, open the sixth programmable valve (V6A) and use the regeneration vacuum pump to vacuum desorb the adsorption bed. At this time, the impurities adsorbed by the adsorbent are desorbed under negative pressure to complete the regeneration of the adsorbent. After the vacuum regeneration gas passes through the regeneration separator, it enters the gas pipeline together with the reverse discharge desorption gas; ④ Pressurization: After the vacuum negative pressure desorption is completed, open the third program-controlled valve (V3A), and slowly pressurize the adsorption tower to the adsorption pressure through the boost regulating valve (V10) to pass the purified product gas in the opposite direction of adsorption, and then the adsorption tower will enter the next adsorption process; Multiple adsorption towers (9) alternately perform the above adsorption and regeneration process to achieve continuous purification of the raw gas; The variable temperature flushing regeneration process comprises the following steps: ⑤ Cutting off the adsorption tower: After the adsorption tower (9) completes negative pressure regeneration, the adsorption tower (9) is cut off through the control system, so that the adsorption tower (9) is isolated from other adsorption towers in the system to prepare for variable temperature flushing regeneration. At this time, the other adsorption towers except the adsorption tower (9) are still operated in a vacuum negative pressure regeneration mode; ⑥ High-temperature flushing regeneration: Open the ninth program-controlled valve (V9), the fourth program-controlled valve (V4A), and the seventh program-controlled valve (V7A). The regeneration gas from outside the boundary area is heated to 240°C by the regeneration heater and then passes through the adsorption tower from top to bottom to flush the adsorption tower bed to the required temperature. The high-temperature flushing desorption gas enters the flare gas network; ⑦ Constant temperature flushing regeneration: When the outlet temperature of the adsorption tower for high temperature flushing regeneration reaches the required temperature, the process of flushing at a high temperature is continued to ensure that the adsorbent is fully regenerated, i.e. constant temperature flushing; ⑧ Low-temperature flushing and regeneration: When the constant temperature flushing is completed, the adsorption tower is flushed at low temperature. At this time, the ninth programmable valve (V9) is closed, and the eighth programmable valve (V8), the fourth programmable valve (V4A), and the seventh programmable valve (V7A) are opened to allow the low-temperature flushing gas with a temperature of ≤40°C to enter the adsorption tower from top to bottom, and the bed layer of the adsorption tower is flushed at low temperature to the required temperature. The regenerated desorption gas enters the flare gas network; ⑨ Putting the adsorption tower into operation: After the low-temperature flushing and regeneration is completed, all program-controlled valves connected to the adsorption tower (9) are closed, and the control system puts the adsorption tower (9) into operation. At this point, the adsorption tower (9) completes a variable temperature flushing and regeneration process.

5. The temperature swing adsorption gas purification process according to claim 4, Features: In the step ②, when the adsorption pressure is low or the regeneration pressure is close to the adsorption pressure, the process step ② is not required.

6. The temperature swing adsorption gas purification process according to claim 4 or 5, Features: When step ② is not present in step ④, the process step ④ is not required.

7. The temperature swing adsorption gas purification process according to claim 4, Features: In the step ⑥, the high temperature flushing regeneration, the gas temperature at the outlet of the adsorption tower regeneration is maintained at 40° C. in the initial stage, and when the temperature is gradually and slowly increased to ≥150° C., the step ⑥ is terminated.

8. The temperature swing adsorption gas purification process according to claim 4, Features: In step ⑦, the constant temperature flushing regeneration is controlled at 150-220° C. according to different constant temperature of the desorbed substances.

9. The temperature swing adsorption gas purification process according to claim 4, Features: In the step ⑧, the low-temperature flushing regeneration, the gas temperature at the outlet of the adsorption tower regeneration is basically maintained at ≥ 150°C in the initial stage, and when the temperature is gradually and slowly reduced to ≤ 45°C, the step ⑧ is terminated.

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