JP5766089B2 - Carbon dioxide recovery and purification method and system - Google Patents

Description

  The present invention relates to a carbon dioxide recovery and purification method and system for collecting carbon dioxide from a supply destination and purifying it, and further purifying the purified carbon dioxide as necessary, and then supplying it to the supply destination. The present invention relates to a method and a system capable of supplying ultra-pure carbon dioxide that can be used in a manufacturing process of electronic components such as the beginning to a supplier.

Carbon dioxide (CO ₂ ) is used in various forms in a gaseous state, and is used in a liquid state or a supercritical state, for example, in a process such as cleaning or drying. In recent years, the use of liquid CO ₂ or supercritical CO ₂ has also been proposed in a cleaning process in the manufacture of semiconductor devices. When liquid CO ₂ or supercritical CO ₂ is used in the manufacture of semiconductor devices or the like, it is necessary to supply liquid CO ₂ or supercritical CO ₂ purified to a high purity with a very small amount of impurities. Further, CO ₂ used in a semiconductor device manufacturing process or the like is required to be recovered and purified and supplied again to the same manufacturing process.

Patent Document 1 discloses a regeneration and recovery apparatus in which CO ₂ is recovered and purified from a cleaning apparatus or a drying apparatus using supercritical CO ₂ or liquid CO ₂ so that the CO ₂ can be used again in the cleaning apparatus. ing. The regeneration and recovery apparatus disclosed in Patent Document 1 lowers the pressure of recovered fluid CO ₂ to leave impurities on the liquid phase side, and liquefies and purifies gas CO ₂ from the gas-liquid separation mechanism. A liquefaction purification mechanism, and a mist separation mechanism and a filter disposed between the gas-liquid separation mechanism and the liquefaction purification mechanism are provided.

By the way, CO ₂ recovered from a cleaning device or a drying device used in a semiconductor device manufacturing process includes moisture, oil, and volatile impurities, and particularly includes alcohols such as isopropyl alcohol (IPA). The regeneration and recovery apparatus of Patent Document 1 can efficiently remove hardly volatile particles and mist, but is not necessarily suitable for removing volatile alcohol represented by IPA from CO ₂ .

Various techniques for purifying CO ₂ by removing impurities are known. For example, Patent Document 2 discloses a technique for removing impurities such as carbonyl sulfide (COS), phosphorus-containing compounds, silicon-containing compounds, and non-methane hydrocarbons in CO ₂ by adsorbing them on a mixed metal oxide. Patent Document 3, the water from in CO _2, oxygen-containing compounds, to remove aromatics and sulfur-containing compounds is passed through the CO ₂ gas and a Y zeolite and a drying agent to the adsorption tower filled as an adsorbent In other words, it is disclosed that two adsorption towers are provided in parallel and the other adsorption tower is regenerated when impurity adsorption removal processing is performed in one of the adsorption towers. Patent Document 4, sulfur compounds, oxygenates and impurities such as hydrocarbons to produce a purified CO ₂ is removed from the CO _2, and passing the CO ₂ to various purification units, after purification CO ₂ It is disclosed to conduct an analysis on. Patent Document 5, water, hydrocarbons and sulfur compounds for removal from the CO _2, the CO ₂ and desiccant and Y zeolite and activated carbon adsorption tower constructed by filling in a single container as an adsorbent It is disclosed to pass.

The method of adsorbing and removing impurities using an adsorbent is a common method for purifying carbon dioxide. Therefore, when CO ₂ recovered from a supply destination is purified and supplied to the supply destination, moisture, oil, volatile It is fully conceivable to use an adsorbent to remove impurities and the like. However, the adsorbent has a limit that will cause impurities to leak later if it is further adsorbed, so if the aeration of CO ₂ is not stopped before this limit is reached, impurities will be added to the purified CO ₂ . The problem of mixing in occurs. Therefore, for example, the aeration is stopped after a lapse of a certain time assumed not to reach the limit, or the threshold value on the safe side with respect to the value required for the purified CO ₂ is set. Then, the analysis of CO ₂ after passing through the adsorbent is performed, and when the threshold value is exceeded, it is determined that the limit of the impurity leaking to the subsequent stage is close, and the ventilation is stopped. In this case, in order to satisfy the required value strictly, it is necessary to stop the aeration of CO ₂ long before the adsorbent reaches the limit, and after the aeration is stopped, the adsorbent is regenerated or replaced. There arises a problem that the adsorption capacity of the adsorbent cannot be used effectively. In addition, if the inlet impurity concentration temporarily rises beyond the assumption, the value required for the purified CO ₂ may not be satisfied.

JP 2005-281016 A JP-T-2006-502957 Special table 2009-506967 Special table 2009-512612 gazette Special table 2009-504383

  There have been some proposals for techniques for purifying carbon dioxide recovered from a semiconductor device manufacturing process and supplying it again to the semiconductor device manufacturing process. In such a technique, it is considered realistic to use an adsorbent in order to remove moisture, oil or volatile impurities contained in the recovered carbon dioxide. However, when an adsorbent is used, there is a problem that the adsorbable amount of the adsorbent cannot be fully utilized, which leads to an increase in initial cost and running cost accompanying an increase in regeneration frequency. .

  An object of the present invention is a carbon dioxide recovery and purification method and system for recovering and purifying carbon dioxide from a supply destination, further purifying the purified carbon dioxide as necessary, and then supplying it again to the supply destination. It is an object of the present invention to provide a method and system that can easily reduce particles, moisture, oil, and volatile impurities in carbon dioxide and that can sufficiently utilize the adsorption capacity of an adsorbent.

  The carbon dioxide recovery and purification system of the present invention is a carbon dioxide recovery and purification system that recovers carbon dioxide from a carbon dioxide supply destination, purifies the recovered carbon dioxide, and supplies it again, and is included in the fluid recovered from the supply destination. A gas-liquid separator that separates carbon dioxide from carbon dioxide, a condenser that condenses gas phase carbon dioxide flowing out from the outlet of the gas-liquid separator to produce liquid carbon dioxide, and a condenser Impurities from gas phase carbon dioxide flowing in the purification line, which are provided in the supply line that supplies carbon dioxide in the liquid state directly or finally to the supply destination and the purification line from the outlet of the gas-liquid separator to the condenser The amount of impurities measured by sampling carbon dioxide flowing through at least one of a plurality of adsorbing portions connected in series to each other and adsorbing portions of the plurality of adsorbing portions. Characterized in that it comprises a part, a.

  The carbon dioxide recovery and purification method of the present invention is a carbon dioxide recovery and purification method for recovering carbon dioxide from a carbon dioxide supply destination, purifying the recovered carbon dioxide, and re-supplying the carbon dioxide. Separating the impurities and carbon dioxide generated in the gas-liquid separator, condensing the gaseous carbon dioxide flowing out from the outlet of the gas-liquid separator with a condenser to form liquid carbon dioxide, and the condenser In the process of sending carbon dioxide, which is in a liquid state, directly or finally to the supply destination, and in the position on the line from the outlet of the gas-liquid separator to the condenser, a plurality of adsorption parts connected in series with each other By venting the carbon dioxide in the gas phase, an impurity removal step for adsorbing and removing impurities from the carbon dioxide in the gas phase, and at least one of the connection positions between the plurality of adsorption parts An analysis step of measuring the impurities by sampling carbon, and having a control step of controlling the ventilation state of the carbon dioxide into the plurality of suction portion, the depending on the measurement result in the analysis step.

  Provided with a plurality of adsorption parts connected in series to each other at a position between a gas-liquid separator that separates carbon dioxide from impurities contained in the recovered fluid and a condenser that condenses the vaporized carbon dioxide, By sampling carbon dioxide flowing through at least one of the connecting positions of the plurality of adsorbing parts so that impurities can be measured, the adsorbing part upstream from the sampling position causes further adsorption. It can be detected that the limit of leakage of impurities is reached. When the upstream adsorption part reaches this limit, the adsorption part downstream from the sampling position hardly adsorbs impurities, so the impurities can be reliably adsorbed and removed by the downstream adsorption part. With respect to the adsorption part on the side, it can be used up to the limit at which impurities leak into the latter stage, and the adsorption capacity can be used up effectively. In addition, since the adsorption load is small and the maintenance period can be set extremely long for the adsorption part on the downstream side, the adsorbent can be used effectively as a whole, and impurity contamination to the subsequent stage is surely prevented. be able to.

It is a figure which shows the structure of the carbon dioxide collection purification system of the 1st Embodiment of this invention. It is a figure which shows the structure of the carbon dioxide collection purification system of 2nd Embodiment. It is a figure which shows the structure of the carbon dioxide collection refinement | purification system of 3rd Embodiment. It is a figure explaining the arrangement | positioning relationship between an adsorption | suction part and a valve.

A carbon dioxide recovery and purification system based on the present invention includes a gas-liquid separator that separates impurities and carbon dioxide (CO ₂ ) contained in a fluid recovered from a supply destination that is a carbon dioxide using apparatus, and an outflow from the gas-liquid separator. to a condenser for condensing the CO ₂ in a gaseous state, a system for purifying the CO ₂ comprises a, a between the outlet and the condenser inlet of the gas-liquid separator CO ₂ is in a gas phase At least two stages of adsorbing portions are arranged in series at the flowing position, and CO ₂ flowing therethrough is sampled at a connecting position between a plurality of adsorbing portions connected in series to measure the impurity concentration in CO _2. And an analysis unit. The CO ₂ liquefied by the condenser can be reused in the carbon dioxide using device. The carbon dioxide using device is, for example, a cleaning device or a drying device used in a semiconductor device manufacturing process.

This carbon dioxide recovery and purification system is provided with a plurality of adsorption units, and the same impurity component is adsorbed and removed by each adsorption unit by filling the same type of adsorbent with each other. It becomes to select the adsorbent to be filled in the adsorption unit in accordance with impurity components to be removed, depending on whether the carbon dioxide used device is what is the supply destination of the recovered purified CO _2, recovered CO ₂ Therefore, it is preferable to select the adsorbent according to the carbon dioxide using apparatus. As a generally known adsorbent for removing water, zeolite, molecular sieves, activated alumina, silica gel, etc. can be used, and for adsorbent for removing organic substances such as isopropyl alcohol (IPA), activated carbon, Molecular sieves, high silica zeolite, and the like can be used. Regardless of whether it is for removing moisture or for removing organic substances, these adsorbents must be preliminarily removed of moisture in the adsorbent by passing dry gas with sufficiently low moisture control before use. Is preferred.

When CO ₂ is flowed in a gaseous state from the gas-liquid separator to the condenser, moisture, oil, and volatile impurities contained in the CO ₂ recovered from the carbon dioxide using device are adsorbed in series. Of these parts, the adsorption is first removed by the adsorption part on the upstream side, ie, the adsorption part on the gas-liquid separator side. At this stage, the impurity component does not appear in the analysis result in the analysis section, and the adsorption section on the downstream side, that is, the adsorption section on the condenser side has not yet adsorbed anything. In the meantime, if the adsorbent in the adsorption section on the upstream side is further adsorbed, the limit will be reached that impurities will leak to the subsequent stage, and as a result, impurity components will appear in the analysis result in the analysis section. Soshitara stops ventilation of CO ₂ with respect to the suction portion of at least the upstream side, performing such replacement of a reproduction process and adsorbent with respect to the suction portion of the upstream side. At this time, impurities leak out from the upstream adsorption section, but the leaked impurities are removed by adsorption by the downstream adsorption section, and thus do not reach the carbon dioxide using apparatus. Further, the impurity component flows into the downstream adsorbing portion for a short time from when the upstream adsorbing portion has reached the limit at which the impurity leaks out until the ventilation is stopped. Therefore, the adsorption capacity of the adsorption part on the downstream side is hardly consumed. The downstream adsorption section needs to be regenerated or replaced in a period where it is assumed that there is still room for the limit. However, since the impurity component hardly flows into the downstream adsorption section in the first place, It is possible to set a very long period until processing or replacement is performed. Since the upstream adsorption section is used up to the limit of the adsorption capacity, it is repeatedly regenerated or exchanged, and the downstream adsorption section can be used as it is for a very long period, so in the carbon dioxide recovery and purification system based on the present invention, As a whole, the adsorbent can be used effectively, and impurity contamination on the carbon dioxide using device side can be prevented.

Various impurities are often mixed in the CO ₂ recovered from the supply destination, and examples of such impurities include IPA. The IPA recovered as an impurity from the supply destination is accumulated as a liquid phase inside the gas-liquid separator, and is discharged out of the system by purging (discharging) the liquid phase at an appropriate time. On the other hand, since CO ₂ exits the gas-liquid separator in the gas phase and proceeds to the adsorption process, it can be separated from IPA.

Also, hardly volatile particles such as metal fine particles contained in CO ₂ recovered from the carbon dioxide using device are accumulated in the liquid phase part in the gas-liquid separator, and thus are discharged out of the system as in the case of IPA. . Moreover, it is removed also by the filter suitably arrange | positioned in a system, Thereby, the contamination by these particles to the carbon dioxide using apparatus side is also prevented.

Note that CO ₂ recovered from the supply destination may be supplied to the gas-liquid separator as a liquid. In such a case, the CO ₂ may be vaporized in the gas-liquid separator by a method such as heating. .

  As the adsorption unit, for example, an adsorption tower in which a tower-like container is filled with an adsorbent and gas is allowed to flow through the container can be used. Other configurations can be used as long as the configuration allows the air to be ventilated. In the following description, an adsorption tower is used as the adsorption unit.

FIG. 1 shows the configuration of a carbon dioxide recovery and purification system according to the first embodiment of the present invention. The carbon dioxide recovery and purification system is for supplying the CO ₂ with respect to the carbon dioxide used device 50 which is a supply destination, and purified to recover the spent CO ₂ from the carbon dioxide used apparatus 50, purified The CO ₂ thus supplied is supplied again to the carbon dioxide using apparatus 50. Here, CO ₂ is directly supplied from the carbon dioxide recovery and purification system to the supply destination and directly recovered from the supply destination. However, a further purification device or recovery device may be used as necessary.

The carbon dioxide recovery and purification system shown in FIG. 1 has a storage tank 11 for temporarily storing high-purity liquid CO ₂ and a pump provided at the outlet of the storage tank 11 in order to supply purified carbon dioxide to the carbon dioxide using device 50. 12 and a filter 13 provided at the outlet of the pump 12, and CO ₂ is supplied to the carbon dioxide using device 50 by the pump 12. Since the pump 12 may generate dust, the filter 13 removes particles generated in the pump 12.

The carbon dioxide recovery and purification system also includes a gas-liquid separator 16 that separates impurities and CO ₂ contained in the recovered fluid by gas-liquid separation in order to purify CO ₂ recovered from the carbon dioxide using device 50, From the adsorption tower A1 connected to the gas phase side outlet of the liquid separator 16, the adsorption tower A2 connected in series to the adsorption tower A1, the filter 17 connected to the outlet of the adsorption tower A2, and the filter 17 a condenser 18 for condensing the flowed gas CO _2, has a, CO ₂ liquefied in the condenser 18 is adapted to be stored in the reservoir 11 described above as a high purity liquid CO _2. The storage tank 11 is also provided with a valve 22 for forcibly discharging (blowing) other low-boiling components (for example, air) mixed as impurity components to the outside. A line from the condenser 18 through the storage tank 11, the pump 12, and the filter 13 to the carbon dioxide using device 50 is a CO ₂ supply line. The storage tank 11 is not necessarily provided. For example, when the condenser 18 itself has a function of holding liquid CO ₂ , it is not necessary to provide the storage tank 11.

  As the gas-liquid separator 16, a gas phase outlet and a valve 23 provided at the liquid phase side outlet, which can discharge (blow) the liquid phase component through the valve 23, are used.

The upstream adsorption tower A1 and the downstream adsorption tower A2 are filled with an adsorbent having the same composition so that the same impurity components can be removed. However, if the same impurities can be removed, the adsorption towers A1 and A2 do not necessarily need to be filled with an adsorbent having the same composition. A sampling line branches off from a connection point between the adsorption tower A1 and the adsorption tower A2, and an analysis unit 30 that performs sampling analysis of impurity components in CO ₂ is provided for the sampling line. The analyzing unit 30 is configured to detect and quantify the impurity component depending on what is the impurity component (for example, moisture, oil or IPA) to be adsorbed and removed by the adsorption tower. When the carbon dioxide using apparatus 50 is a cleaning apparatus or a drying apparatus in a semiconductor device manufacturing process, the recovered CO ₂ contains a large amount of IPA as an impurity. Most of the IPA is separated and removed in the gas-liquid separator 16, but part of it is contained in the gas phase together with CO ₂ , so it is necessary to remove it in the adsorption tower. It is preferable to use a material capable of adsorbing and removing IPA as the adsorbent and a material capable of detecting and quantifying IPA as the analysis unit 30.

The CO ₂ recovered from the carbon dioxide using device 50 is supplied to the gas-liquid separator 16. When the fluid recovered from the supply destination contains IPA or the like, the IPA is accumulated as a liquid phase inside the gas-liquid separator 16, and the IPA is removed from the system by purging (discharging) the liquid phase at an appropriate time. Discharged. On the other hand, since CO ₂ exits the gas-liquid separator 16 in the gas phase and proceeds to the adsorption process, it can be separated from IPA. Further, the dispersion or penetration tends particles in liquid CO ₂ or a less volatile in CO _2, because almost in the gas-liquid separator 16 is not shifted to the vapor phase side, the gas flows out from the gas-liquid separator 16 CO It will be removed from ₂ . Since these particles remain on the liquid phase side, they can be discharged (purged) out of the system by opening the valve 23 provided at the liquid phase side discharge port of the gas-liquid separator 16. The gaseous CO ₂ from the gas-liquid separator 16 then flows into the adsorption tower A1, where impurities (water, oil and volatile impurities) intended for removal in the adsorption tower are removed, flows into the adsorption tower A2, further fed to the condenser 18 via the filter 17 is liquefied and supplied as liquid CO ₂ to the reservoir 11. The filter 17 removes particles that could not be removed by the gas-liquid separator 16 and particles generated in the adsorption towers A1 and A2. As a result, in the storage tank 11, the hardly volatile particles are removed by the gas-liquid separator 16 and the filter 17, and the removal target impurities (water, oil or volatile impurities) are removed by the adsorption tower A 1. Pure liquid CO ₂ will be stored. This high-purity liquid CO ₂ is supplied to the carbon dioxide using device 50 by the pump 12 as described above.

In this carbon dioxide recovery and purification system, gas CO ₂ flows from the gas-liquid separator 16 through the adsorption towers A1 and A2 and the filter 17 to the condenser 18, whereby the CO ₂ purification process is performed. Therefore, the line from the gas-liquid separator 16 to the condenser 18 is called a purification line.

When the purification process of CO ₂ is performed, the amount of impurities adsorbed on the adsorption tower A1 gradually increases, and eventually, the adsorption tower A1 reaches the limit that if the adsorption tower A1 adsorbs more than this, the adsorption tower A1 reaches the limit. Break. The analysis unit 30 samples the CO ₂ flowing through the adsorption tower A1 and the adsorption tower A2 through the sampling line and monitors the impurity concentration constantly or step by step, and if the impurity concentration exceeds a certain threshold value, the adsorption is performed. It is determined that the tower A1 has reached the limit. When it is detected that the adsorption tower A1 has reached the limit, the flow of CO ₂ to the adsorption towers A1 and A2 is quickly stopped by stopping the flow of CO _{2 in} the purification line, and then the broken line shown in the figure. As shown, the line is switched so that the regeneration gas from the regeneration gas source 41 passes through the adsorption tower A <b> 1 through the heater 43 and is discharged as the regeneration exhaust gas 42. Then, the regeneration gas heated by the heater 43 is passed through the adsorption tower A1, and the impurities adsorbed in the adsorption tower A1 are desorbed and discharged out of the system to regenerate the adsorbent in the adsorption tower A1. I do. At this time, it is preferable that the direction of the regeneration gas flow in the adsorption tower A1 is opposite to the original direction of CO ₂ flow. When the regeneration process is completed, the line is quickly returned to its original state, CO _{2 is} passed through the adsorption towers A1 and A2, and the purification process is resumed. Instead of performing the regeneration treatment of the adsorption tower A1, the adsorption tower A1 itself may be replaced or the adsorbent in the adsorption tower A1 may be replaced. Further, the regeneration gas from the regeneration gas source 41 is supplied not from between the adsorption tower A1 and the adsorption tower A2, but from the latter stage of the adsorption tower A2, or both, and the regeneration treatment of the adsorption tower A2 is performed together. May be.

Due to the sampling time interval in the analysis in the analysis unit 30 and the time required for the analysis result to be obtained, there is a slight time lag from when the adsorption tower A1 reaches the limit at which the impurity leaks out until it becomes clear. (Time difference) may occur. However, the adsorption tower A2 is provided on the downstream side of the adsorption tower A1, and the impurity component flowing out from the adsorption tower A1 within the time lag is reliably adsorbed and removed by the adsorption tower A2, so that the carbon dioxide using apparatus 50 Impurities do not flow out to the side. Further, during the period when the regeneration process is being performed, the flow of CO ₂ from the gas-liquid separator 16 toward the condenser 18 is stopped, so that impurities flow out to the carbon dioxide using device 50 side during this period. Nor.

  Since the adsorption load of the adsorption tower A2 is much smaller than that of the adsorption tower A1, the adsorption tower A2 is periodically regenerated during a period in which it is assumed that it will still have sufficient adsorption capacity in anticipation of safety. Processing or replacement may be performed. In the carbon dioxide recovery and purification system shown in FIG. 1, the adsorption tower A1 can be regenerated or exchanged after reaching the limit, so that the adsorbent can be effectively used as a whole.

  FIG. 2 shows a carbon dioxide recovery and purification system according to the second embodiment of the present invention.

In the system shown in FIG. 1, since the flow of CO ₂ from the gas-liquid separator 16 to the condenser 18 must be stopped during the period during which the adsorption tower A1 is being regenerated, purification of high-purity CO ₂ is performed. In other words, the continuous supply of CO ₂ to the carbon dioxide using apparatus 50 that is the supply destination cannot be performed. Therefore, in the carbon dioxide recovery and purification system shown in FIG. 2, another adsorption tower B is provided so as to bypass the adsorption towers A1 and A2 connected in series, and the regeneration treatment or replacement is performed on the adsorption tower A1. During this period, gas CO ₂ from the gas-liquid separator 16 is supplied to the filter 17 via the adsorption tower B. The adsorption tower B is filled with the same adsorbent as that filled in the adsorption towers A1 and A2, but is not limited thereto as long as it is a filler that adsorbs the same impurities.

In the carbon dioxide recovery and purification system shown in FIG. 2, during normal operation, the gas CO ₂ from the gas-liquid separator 16 passes through the adsorption towers A1 and A2 and does not pass through the adsorption tower B, thereby purifying the CO ₂ . Execute the process. The analysis unit 30 monitors the impurities contained in the CO ₂ at the outlet of the adsorption tower A1 sequentially or one by one. When the amount of impurities exceeds the threshold, the adsorption tower A1 reaches the limit at which the impurities leak out. judge. When it is detected that the adsorption tower A1 has reached the limit, the passage of CO ₂ to the adsorption towers A1 and A2 is stopped. Instead, the CO ₂ from the gas-liquid separator 16 passes through the adsorption tower B and is filtered by the filter 17. Next, the line is switched so as to flow to the next, and then, as indicated by the broken line in the figure, the regeneration gas from the regeneration gas source 41 passes through the adsorption tower A1 via the heater 43 and is discharged as the regeneration exhaust gas 42. Switch the line. Then, while maintaining the flow of CO ₂ through the adsorption tower B, the regeneration gas heated by the heater 43 is vented to the adsorption tower A1, and the impurities adsorbed on the adsorption tower A1 are desorbed to the outside of the system. By discharging, the adsorbent in the adsorption tower A1 is regenerated. At this time, the direction of the regeneration gas flow in the adsorption tower A1 is preferably opposite to the original direction of the CO ₂ flow, but is not limited thereto. When the regeneration process is completed, the line is quickly returned to the original state, the ventilation to the adsorption tower B is stopped, and CO ₂ is aerated through the adsorption towers A1 and A2. Instead of performing the regeneration treatment of the adsorption tower A1, the adsorption tower A1 itself may be replaced or the adsorbent in the adsorption tower A1 may be replaced. In addition, the regeneration gas source 41 is not installed between the adsorption tower A1 and the adsorption tower A2, but is installed in the latter stage of the adsorption tower A2, or in both of them. You may go.

Due to the sampling time interval in the analysis in the analysis unit 30 and the time required for the analysis result to be obtained, there may be a slight time lag from when the adsorption tower A1 reaches the limit at which impurities leak out until it is determined. There is sex. However, the adsorption tower A2 is provided on the downstream side of the adsorption tower A1, and the impurity component flowing out from the adsorption tower A1 within the time lag is reliably adsorbed and removed by the adsorption tower A2, so that the carbon dioxide using apparatus 50 Impurities do not flow out to the side. Further, continuous during the period of performing the regeneration process of the adsorption tower A1, the purification treatment CO ₂ by bubbling CO ₂ into the adsorption tower B are performed continuously, without interrupting the whole process In particular, it is possible to continue supplying purified CO ₂ to the carbon dioxide using apparatus 50.

  The adsorption load of the adsorption tower A2 is much smaller than that of the adsorption tower A1, and since the adsorption tower B is used only during the regeneration period of the adsorption tower A1, the adsorbing towers A2 and B are expected to be safe. Regeneration processing or replacement may be performed periodically in a period during which it is assumed that the adsorption capacity is still sufficient. In the carbon dioxide recovery and purification system shown in FIG. 2, the adsorbent can be effectively used as a whole because the adsorption tower A1 can be regenerated or exchanged after reaching the limit at which impurities leak out.

  FIG. 3 shows a carbon dioxide recovery and purification system according to a third embodiment of the present invention.

In the carbon dioxide recovery and purification system shown in FIG. 2, but is performed by continuing the purification process of the CO ₂ by bubbling CO ₂ into the adsorption tower B is when performing the regeneration treatment of the adsorption tower A1, adsorption column A1 If the regeneration process takes time, the amount of adsorption of impurities in the adsorption tower B increases, and the absorption limit of the adsorption tower B may be reached earlier than expected. Therefore, in the carbon dioxide recovery and purification system shown in FIG. 3, instead of the adsorption tower B, an adsorption tower B1 and an adsorption tower B2 connected in series are provided, and a sampling line is also connected to the connection point of the adsorption towers B1 and B2. Thus, the analysis unit 30 can analyze the impurity concentration at the outlet of the adsorption tower B1. Further, the regeneration gas from the regeneration gas source 41 can be supplied also to the adsorption tower B1, and the regeneration treatment can be alternately performed on the adsorption towers A1 and B1. In addition, the regeneration gas from the regeneration gas source 41 may be supplied from the latter stage of the adsorption towers A2 and B2, so that the regeneration processing of the adsorption towers A2 and B2 may be performed together. Further, the regeneration gas from the regeneration gas source 41 is supplied not from between the adsorption towers A1 and B1 and the adsorption towers A2 and B2, but from the latter stage of the adsorption towers A2 and B2, or both of them. , B2 may be reproduced together.

  In the following description, the adsorption towers A1 and A2 are collectively referred to as an adsorption line A, and the adsorption towers B1 and B2 are collectively referred to as an adsorption line B.

Or bubbling CO ₂ adsorption line B or bubbling CO ₂ adsorption line A in the initial state can be arbitrarily selected, but here, the gas CO ₂ from the gas-liquid separator 16 passes through the suction line A It shall not pass through the adsorption line B. If the purification process of CO ₂ is continued in this state, the impurity concentration at the outlet of the adsorption tower A1 increases and eventually exceeds the threshold value. If the threshold value is exceeded, it is determined that the adsorption tower A1 has reached the limit at which impurities leak out, and the ventilation of CO ₂ to the adsorption line A, that is, the adsorption towers A1 and A2, is stopped. The line is quickly switched so that CO ₂ from the refrigerant flows through the adsorption line B to the filter 17. Then, regeneration gas is passed through the adsorption tower A1 from the regeneration gas source 41 through the heater 43, and regeneration processing of the adsorption tower A1 is performed. At this time, the purification process of CO ₂ is performed via the adsorption line B. Even after the regeneration process of the adsorption tower A1 is completed, CO ₂ is continuously vented to the adsorption line B. Among them, the adsorption tower B1 reaches the limit and the impurity concentration at the outlet of the adsorption tower B1 becomes high, and this is detected by the analysis unit 30.

When it is detected that the adsorption tower B1 has reached the limit, this time, the ventilation of CO ₂ to the adsorption line B is stopped, and instead, the CO ₂ from the gas-liquid separator 16 passes through the adsorption line A and is filtered. The line is switched quickly so that it flows to 17. Then, the regeneration gas is passed through the adsorption tower B1 from the regeneration gas source 41 through the heater 43, and the regeneration process of the adsorption tower B1 is performed. At this time, the purification process of CO ₂ is performed via the adsorption line A. Even after the regeneration process of the adsorption tower B1 is completed, CO ₂ is continuously vented to the adsorption line A. Since it has returned to the initial state, the above operation is repeated thereafter, and CO ₂ is alternately ventilated to the adsorption lines A and B, and the regeneration to the adsorption tower A1 or the adsorption tower B1 is performed at a timing when it is not vented. Process.

  FIG. 4 is a diagram for explaining line switching between adsorption lines A and B and line switching for regeneration processing of adsorption towers A1 and A2 in the carbon dioxide recovery and purification system shown in FIG. The adsorption towers A1, A2, B1, and B2 and valves AV1 to AV8 connected to these are shown. Valves AV1 and AV3 are provided between the line from the gas-liquid separator 16 and the inlets of the adsorption towers A1 and B1, respectively, and valves AV2 and AV4 are provided between the outlets of the adsorption towers A2 and B2 and the filter 17, respectively. It has been. Valves AV7 and AV8 for discharging the regenerated exhaust gas 42 are provided at the inlets of the adsorption towers A1 and B1. In order to supply the regeneration gas supplied from the regeneration gas source 41 and heated by the heater 43 to the adsorption towers A1 and B1 from the outlet side, valves AV5 and AV6 are provided between the heater 43 and the adsorption towers A1 and B1, respectively. It has been.

  Next, opening / closing control of these valves AV1 to AV8 will be described. The operation of the carbon dioxide recovery and purification system shown in FIG. 3 can be summarized in the following steps 1 to 4. In step 1, a normal suction operation is performed in the suction line A, and the suction line B is not vented. When it is detected in step 1 that the adsorption tower A1 has reached the limit at which impurities leak, the process proceeds to step 2, and in step 2, a normal adsorption operation is performed in the adsorption line B, and at the same time, the regeneration process of the adsorption tower A1 is performed. Run. When the regeneration process of the adsorption tower A1 is completed, the process proceeds to step 3. In step 3, a normal adsorption operation is performed in the adsorption line B, and the adsorption line A is not vented. Thereafter, when it is detected that the adsorption tower B1 has reached the limit, the routine proceeds to step 4, where a normal adsorption operation is performed in the adsorption line A, and at the same time, regeneration processing of the adsorption tower B1 is executed. When the regeneration process of the adsorption tower B1 is completed, the process returns to the first step 1. Table 1 shows valve opening / closing control for carrying out such steps 1 to 4.

In the system shown in FIG. 3, it becomes clear after the adsorption tower A1 or the adsorption tower B1 reaches the limit due to the sampling time interval in the analysis in the analysis unit 30 or the time required until the analysis result is obtained. Some time lag may occur. However, the adsorption towers A2 and B2 are provided downstream of the adsorption towers A1 and B1, respectively, and the impurity components flowing out from the adsorption towers A1 and B1 within the time lag are reliably adsorbed and removed by the adsorption towers A2 and B2. Therefore, impurities do not flow out to the carbon dioxide using device 50 side. Moreover, the purification treatment CO ₂ by allowing CO ₂ is vented alternately adsorption line B and the suction line A are executed continuously, continuously purified without interrupting the whole process The CO ₂ using device 50 can continue to be supplied.

  Since the adsorption loads of the adsorption towers A2 and B2 are much smaller than those of the adsorption towers A1 and B1, it is assumed that the adsorption towers A2 and B2 will still have sufficient adsorption capacity in anticipation of safety. What is necessary is just to perform a reproduction | regeneration process or replacement | exchange regularly at a period. In the carbon dioxide recovery and purification system shown in FIG. 3, the adsorption towers A1 and B1 can be regenerated or exchanged after reaching the limit at which impurities leak out. Available.

DESCRIPTION OF SYMBOLS 11 Storage tank 12 Pump 13,17 Filter 16 Gas-liquid separator 18 Condenser 22,23 Valve 30 Analysis part 41 Regenerated gas source 42 Regenerated exhaust gas 43 Heater 50 Carbon dioxide using apparatus A1, A2, B, B1, B2 Adsorption tower AV1- AV8 valve

Claims (12)

A carbon dioxide recovery and purification system that recovers carbon dioxide from a carbon dioxide supply destination, purifies the recovered carbon dioxide, and re-supplyes the carbon dioxide.
A gas-liquid separator that separates carbon dioxide from impurities contained in the fluid recovered from the supply destination;
A condenser for condensing gas phase carbon dioxide flowing out from the outlet of the gas-liquid separator to produce liquid carbon dioxide;
A supply line for directly or finally supplying carbon dioxide in a liquid state in the condenser to a supply destination;
A plurality of adsorbers connected in series to adsorb and remove impurities from gas phase carbon dioxide flowing through the purification line, provided in a purification line from the outlet of the gas-liquid separator to the condenser;
A sampling line that samples carbon dioxide that is branched from at least one of the connection lines that connect the plurality of adsorbing portions and flows through the connection line ;
An analyzer for measuring impurities of carbon dioxide sampled from the sampling line ;
Equipped with a,
The impurity is at least one of water and organic matter,
The sampling line impurity components to be adsorbed and removed by the plurality of suction portion connected to both ends of the connection line which is branched to said same der Rukoto, carbon dioxide recovery purification systems. The carbon dioxide recovery and purification system according to claim 1, wherein each of the plurality of adsorption units is filled with the same type of adsorbent .   The carbon dioxide recovery and purification system according to claim 1, wherein one or more adsorption units are further provided in parallel with the plurality of adsorption units connected in series.   A pipe for supplying regeneration gas to at least an adsorption part other than the adsorption part located at the end of the carbon dioxide flow among the plurality of adsorption parts connected in series, and discharging the regeneration gas to the outside of the purification line The carbon dioxide recovery and purification system according to any one of claims 1 to 3, further comprising a pipe for performing the operation. The plurality of suction parts connected in series as a first suction line, a second suction line independent from the first suction line is provided in parallel to the first suction line,
The second adsorption line has a plurality of adsorption portions connected in series to adsorb and remove the impurities from carbon dioxide,
2. The carbon dioxide recovery and purification according to claim 1, wherein the analysis unit also samples carbon dioxide flowing through at least one of the connection positions of the plurality of adsorption units of the second adsorption line to measure the impurities. system. A result of measuring the impurity of the carbon dioxide sampling from at least one of the connecting lines between each other of the plurality of suction portion of the first adsorption lines, the plurality of suction portion of the second adsorption line The ventilation state with respect to the first and second adsorption lines is controlled according to a result of sampling the carbon dioxide flowing through at least one of the connection positions between them and measuring the impurities. Carbon dioxide recovery and purification system.   A pipe for supplying a regeneration gas to an adsorption unit other than the adsorption unit located at the end in the flow of carbon dioxide among the plurality of adsorption units of the first adsorption line; and a plurality of the second adsorption line A pipe for supplying regeneration gas to an adsorption part other than the adsorption part located at the end in the flow of carbon dioxide among the adsorption parts, and a pipe for discharging the regeneration gas out of the purification line are provided. The carbon dioxide recovery and purification system according to claim 5 or 6. A carbon dioxide recovery and purification method that recovers carbon dioxide from a carbon dioxide supply destination, purifies the recovered carbon dioxide, and supplies the purified carbon dioxide again.
Separating the impurities and carbon dioxide contained in the fluid recovered from the supply destination in a gas-liquid separator;
A step of condensing gaseous carbon dioxide flowing out from the outlet of the gas-liquid separator with a condenser to form liquid carbon dioxide;
Sending carbon dioxide in a liquid state in the condenser directly or finally to the supply destination;
By venting the carbon dioxide in the gas phase state to a plurality of adsorbing portions connected in series with each other at a position on the line from the outlet of the gas-liquid separator to the condenser, An impurity removal step for adsorbing and removing impurities;
An analysis step of measuring the impurity of the carbon dioxide by sampling the carbon dioxide flowing through the connection line by a branch sampling line from at least one connection line for connecting mutually the plurality of suction portion,
A control step of controlling the aeration state of carbon dioxide to the plurality of adsorption portions according to the measurement result in the analysis step;
I have a,
The impurity is at least one of water and organic matter,
The sampling line impurity components to be adsorbed and removed by the plurality of suction portion connected to both ends of the connecting line which is branched to said same der Rukoto, carbon dioxide recovery and purification methods.   The carbon dioxide is ventilated to an adsorbing portion provided in parallel to the plural adsorbing portions connected in series when the aeration of carbon dioxide to the plural adsorbing portions is stopped in the control step. Item 9. The carbon dioxide supply purification method according to Item 8.   When the flow of carbon dioxide to the plurality of adsorbing units is stopped in the control step, among the adsorbing units other than the adsorbing unit located at the end in the flow of carbon dioxide among the plurality of adsorbing units connected in series The carbon dioxide supply and purification method according to claim 8 or 9, further comprising a step of supplying a regeneration gas to regenerate the adsorption unit. In the impurity removal step, the plurality of adsorption parts connected in series as a first adsorption line are independent of the first adsorption line in parallel with the first adsorption line and the first adsorption line. A process of ventilating carbon dioxide alternately to a second adsorption line having a plurality of adsorption parts connected in series to adsorb and remove the impurities from carbon dioxide,
In the analyzing step, the impurity is measured by sampling carbon dioxide flowing through at least one of the connection positions of the plurality of adsorbing portions of the second adsorption line,
In the control step, a result of measuring the impurity of the carbon dioxide sampling from at least one of the connecting lines between each other of the plurality of suction portion of the first adsorption line, said second adsorption line The ventilation state with respect to the first and second adsorption lines is controlled according to a result of sampling the carbon dioxide flowing through at least one of the connection positions of the plurality of adsorption portions and measuring the impurities. Item 9. The method for recovering and purifying carbon dioxide according to Item 8.   When the flow of carbon dioxide to the first adsorption line is stopped in the control step, at least one of the plurality of adsorption portions of the first adsorption line other than the adsorption portion located at the end in the flow of carbon dioxide A regeneration gas is supplied to the adsorption unit to regenerate the adsorption unit, and when the aeration of carbon dioxide to the second adsorption line is stopped in the control step, a plurality of adsorptions of the second adsorption line are performed. The carbon dioxide supply and purification method according to claim 11, comprising a step of supplying regeneration gas to at least an adsorption part other than the adsorption part located at an end in the flow of carbon dioxide among the parts to regenerate the adsorption part. .

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