JP2009247973A - Refining method and refining apparatus for target gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently provide a refined gas not containing mist components under a simple operation condition or with an apparatus configuration when refining a target gas from a raw material gas containing the target gas and an unneeded gas by using an absorbing liquid. <P>SOLUTION: The method for refining the target gas from the raw material gas containing the target gas and the unneeded gas by using the absorbing liquid which preferentially absorbs the target gas includes: an absorption process of making a rotor 1 capable of rotating around a rotary axial center O1 receive the absorbing liquid, introducing the raw material gas into the rotor 1 while rotating the rotor 1 at a first rotation speed and making centrifugal force act on the absorbing liquid, and making the absorbing liquid preferentially absorb the target gas in the raw material gas under a first temperature and a first pressure: and a recovery process of regenerating and recovering gas components from the absorbing liquid under a second temperature and a second pressure while rotating the rotor 1 at a second rotation speed and making the centrifugal force act on the absorbing liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for concentrating and purifying a target gas of a specific component from a raw material gas.

  As a method for purifying a specific target gas from a source gas, for example, a method using a membrane or a method using adsorption or absorption is known.

  The method using a membrane utilizes the property that the speed of passing through the membrane differs depending on the type of molecule. For example, a membrane is used as a method for removing water contained in ethanol.

  In the method using a membrane, since most gas components have a permeation coefficient with respect to the membrane, it is necessary to determine the separation conditions with due consideration of the gas permeation characteristics of the membrane and the type of gas included. In addition, in order to achieve ultra-high purity of gas, it is often necessary to devise measures to gradually improve the purity of the target gas by treating the gas containing impurities in multiple stages using a multistage cascade film. In order to improve the rate, the apparatus is often complicated.

  As a method by adsorption, for example, a method of using zeolite as an adsorbent and concentrating by specifically adsorbing or desorbing a specific size molecule using the uniform pore diameter of the zeolite is generally known. Yes. Other examples include a method utilizing adsorption of specific molecules to an adsorbent component adsorbed on alumina, silica gel, or activated carbon. For example, when activated carbon impregnated with copper chloride is used, carbon monoxide can be concentrated (see, for example, Patent Document 1). In the method using adsorption, the target gas can generally be adsorbed and desorbed in a short cycle by ventilating the raw material gas through the adsorbent and changing the pressure or temperature. Such an adsorption method is widely used industrially as a pressure swing adsorption method (PSA method) or a temperature swing adsorption method (TSA method).

  However, since the method by adsorption also adsorbs gas other than the gas component to be adsorbed, it is difficult to increase the specific gas component to high purity by one operation. Therefore, it is necessary to devise in order to obtain a high purity gas, and the operation procedure tends to be complicated.

  In the case of the method by absorption, if the absorption liquid that specifically absorbs a specific gas component is used as the absorption liquid that is a component of the method, the target gas component can be purified with high purity. It is expected to be possible. For example, a method using an alkanolamine aqueous solution when concentrating carbon dioxide (see, for example, Patent Document 2) or a method using an absorbing solution in which a copper compound used for carbon monoxide purification / recovery is used (for example, Patent Document) 3), a method using an aqueous silver nitrate solution for separating olefin and alkane (for example, see Non-Patent Document 1) and the like are well known. In this absorption method, it is often possible to achieve high purity by a single operation.

  However, in the absorption method, since the mist of the absorbing liquid is mixed in the regeneration gas, it is difficult to increase the regeneration speed, and it is necessary to provide a demister and a washing tower to remove the mist component. Have. Further, fine droplets are often contained in the purified gas even through the demister, and eventually the fine droplets need to be removed by a washing tower. Therefore, the apparatus for removing such mist becomes complicated.

JP 2005-289761 A Japanese Patent Laid-Open No. 06-285333 US 4950462 Papers Solubility of Propylene in Aqueous Silver Nitrate, I.H.Cho, D.L.Cho, H.K.Yasuda, and T.R.Marrero, J.Chem.Eng.

  The present invention has been conceived under such circumstances, and in purifying the target gas using the absorbing liquid from the source gas containing the target gas and unnecessary gas, a purified gas containing no mist component is used. The object is to obtain it efficiently with simple operating conditions or equipment configuration.

  A method for purifying a target gas provided by the first aspect of the present invention is a method for purifying a target gas from a source gas containing the target gas and an unnecessary gas using an absorbing liquid that preferentially absorbs the target gas. A method in which the absorption liquid is received by a rotor that is rotatable about a predetermined axis, and the rotor is rotated at a first rotation speed to apply centrifugal force to the absorption liquid, while the raw material is An absorption step of introducing gas into the rotor and preferentially absorbing the target gas in the raw material gas into the absorption liquid at a first temperature and a first pressure; and the rotor at a second rotational speed. And a recovery step of regenerating and recovering the gas component from the absorbing liquid under a second temperature and a second pressure while rotating and applying a centrifugal force to the absorbing liquid. Here, in the absorption step and the recovery step, the second pressure is set lower than the first pressure, the second temperature is set higher than the first temperature, or the second pressure is set. It is only necessary to satisfy at least one of the conditions that the rotation speed is lower than the first rotation speed.

  The present inventors diligently studied a method for easily obtaining a purified gas not containing a mist component in purifying a target gas using an absorption method having excellent gas component selectivity. Thus, the inventors have found that generation of mist can be prevented, and have completed the present invention. In this purification method, gas is absorbed or regenerated while the rotor in which the absorbing liquid is received is rotated. At this time, a centrifugal force acts on the absorbing liquid in the rotor, and the absorbing liquid is pressed against the side wall of the rotor, and the liquid level of the absorbing liquid is spaced a predetermined distance in the radial direction from the rotational axis of the rotor. In position. At this time, the absorbing liquid is accelerated in proportion to the distance from the rotation axis.

  In the absorption process, the pressure applied to the inside of the absorption liquid is increased, and the gas can be absorbed into the absorption liquid in the same manner as in the method of contacting the gas in a high pressure state. Therefore, under the same gas pressure, a larger amount of gas can be absorbed by the absorption liquid than the conventional absorption operation in the gravitational field.

  When the gas is regenerated from the absorbing liquid to recover the regenerating gas in the recovering process, even if mist is generated accompanying the regenerating gas, the mist is subjected to a considerable acceleration, and the liquid of the absorbing liquid is promptly applied. Captured on the surface. In this way, purified gas containing no mist component can be obtained.

  Preferably, the method further includes a discharge step of discharging the gas in the space portion of the rotor from the rotor that has completed the absorption step between the absorption step and the recovery step. In this case, the gas in the space portion of the rotor may be replaced with a high-purity target gas. Preferably, a part of the gas recovered in the recovery step is introduced into the rotor as a high-purity target gas.

  An apparatus for purifying a target gas provided by the second aspect of the present invention is for purifying a target gas from a source gas containing the target gas and an unnecessary gas by using an absorbent that preferentially absorbs the target gas. An apparatus that is rotatable around a predetermined axis, a rotor for receiving the absorption liquid, a raw material gas introduction means for introducing a raw material gas into the rotor, and a regeneration gas from the rotor A recovery gas recovery means for recovering the rotor, a rotational drive means for rotationally driving the rotor, a temperature adjusting means for adjusting the temperature in the rotor, and a pressure adjusting means for adjusting the pressure in the rotor. . Preferably, the rotor is provided with a baffle plate that extends inwardly from the inner surface of the side wall of the rotor. According to the purification apparatus having such a configuration, the purification method according to the first aspect of the present invention can be appropriately performed.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, as a preferred embodiment of the present invention, for example, a method for concentrating and purifying propylene gas from a raw material gas containing propylene (target gas) and propane (unnecessary gas) will be specifically described with reference to the drawings. .

  FIG. 1 is a schematic configuration diagram of a gas purification device X1 according to the first embodiment of the present invention. The gas purification apparatus X1 is configured to be able to purify the crude propylene gas supplied from the cylinder Y by the target gas purification method according to the present invention. The rotor 1, the support 2, the drive unit 3, A pressure regulator 4, a switching valve 5, a rotary joint 6, a gas recovery port 7, a gas discharge port 8, and a pipe connecting them are provided.

  The cylinder Y is for supplying crude propylene gas as a raw material gas to the gas purification apparatus X1, and the crude propylene gas is sealed under high pressure conditions. The crude propylene gas contains propylene as a main component and propane as an impurity. The cylinder Y is connected to a pipe L1 for flowing the source gas. The pipe L1 is connected to the pipes L2 and L4 via the switching valve 5.

  The rotor 1 has a substantially cylindrical closed container shape, and an absorption liquid is received therein. Examples of the absorbing liquid include an aqueous silver nitrate solution prepared to a predetermined concentration. The rotor 1 is supported by the support body 2 via a bearing (not shown), for example, and can rotate around the rotation axis O1. The rotor 1 and the support body 2 constitute a so-called centrifuge. The support 2 is attached with a temperature adjusting means (not shown) for maintaining the absorbing liquid in the rotor 1 at a desired temperature. The temperature adjusting means is configured to flow a temperature control medium made of gas or liquid, for example, through a jacket provided around the support 2.

  A pipe L <b> 3 is connected to the upper center of the rotor 1, and the tip of the pipe L <b> 3 is opened in the rotor 1. The pipe L3 is connected to the pipe L2 through the rotary joint 6. Thereby, even if the pipe L3 rotates as the rotor 1 rotates, the gas flows smoothly between the pipes L2 and L3.

  The drive unit 3 is for driving the rotor 1 to rotate, and is connected to the lower center of the rotor 1 via a rotating shaft 31. The drive unit 3 includes, for example, a motor and a control unit for the motor, and can rotate the rotor 1 at a desired rotation speed.

When the drive unit 3 rotates the rotor 1 at a rotation speed (number of rotations) higher than a predetermined value, centrifugal force acts on the absorption liquid in the rotor 1 and the absorption liquid is pressed against the side wall 1 a of the rotor 1. At this time, the liquid level of the absorbing liquid is located at a predetermined distance in the radial direction from the rotation axis O1 (the position of the liquid level is represented by a broken line in FIG. 1). Here, the centrifugal acceleration a of an object rotating at a speed v on a circumference r from the rotation axis O1 is represented by a = v ² / r. The centrifugal acceleration applied to the absorbing liquid is expressed using G (G = gravitational acceleration, 9.8 m / s ² ) in the case of the distance r (m) from the rotation axis O1 and the rotation speed n. 2πr × n) ² /r/9.8=4π ² × n ² × r / 9.8, and the absorption liquid is proportional to the distance from the rotational axis O1 and is the square of the rotational speed of the rotor 1 Centrifugal acceleration proportional to is acting. For example, when the distance from the rotation axis O1 is 20 cm, when the rotor 1 is rotated at 50 revolutions per second, a centrifugal acceleration as large as about 2000 G is applied. Even when the rotor 1 is rotated at 20 revolutions per second at a distance of 10 cm from the rotational axis O1, a centrifugal acceleration of about 160 G is applied. The centrifugal force acting on the absorbing liquid is calculated by multiplying the centrifugal acceleration by the mass of the absorbing liquid that rotates. Therefore, in the absorption liquid in the centrifugal field, the pressure applied to the liquid is increased as the rotation distance increases from the rotation axis O1, and the same state as that of applying a high gas pressure is realized. As a result, compared with a normal gravitational field, the solubility of propylene in an absorbing solution (silver nitrate aqueous solution) is increased despite a low gas pressure.

  The pressure regulator 4 is for controlling the raw material gas supplied from the cylinder Y to a predetermined pressure and introducing it into the rotor 1, and is provided in the pipe L1.

  The switching valve 5 is for switching the gas flow between the pipes L1, L2, L4 connected thereto. Specifically, it is possible to switch between a state in which the gas in the pipe L1 flows to the pipe L2 and a state in which the gas in the pipe L2 flows to the pipe L4.

  The pipe L4 is for guiding the gas from the rotor 1 to the gas recovery port 7. A back pressure valve 10 is provided in the pipe L4. The back pressure valve 10 is controlled in opening degree so that the inside of the rotor 1 has a predetermined pressure. A pipe L5 is also connected to the pipe L4 in a branched shape. The pipe L <b> 5 is for guiding a part of the gas from the rotor 1 to the gas discharge port 8. Valves 11 and 12 are provided in the pipes L4 and L5.

  The gas purifier X1 includes a pressure regulator 4, a switching valve 5, a back pressure valve 10, and a controller (not shown) for controlling the operation of the valves 11 and 12.

  When performing the purification method of the target gas of the present invention using the gas purification apparatus X1 having the above-described configuration, first, while rotating the rotor 1 at a predetermined rotational speed, the pressure regulator 4 is changed from the cylinder Y, The raw material gas is introduced into the rotor 1 through the switching valve 5, the rotary joint 6, and the pipes L1 to L3. The rotational speed (the number of rotations) of the rotor 1 is, for example, 10 to 200 revolutions per second, more preferably 10 to 100 revolutions per second, although it depends on the diameter of the rotor. The centrifugal acceleration is, for example, 80 to 32220 G for a rotor having a diameter of 40 cm.

  The raw material gas contains propylene as a main component and propane as an impurity as described above, and the propylene concentration and the propane concentration of the raw material gas supplied from the cylinder Y are, for example, 95 to 99.m. 8% and 0.2 to 5.0%.

  The absorbing liquid in the rotor 1 is pressed against the side wall 1a by the rotation of the rotor 1, and the liquid level of the absorbing liquid is at a position spaced apart from the rotation axis O1 by a predetermined distance in the radial direction. In the rotor 1, when the raw material gas is introduced through the pipe L <b> 3, the raw material gas is sequentially absorbed into the absorbing liquid by coming into contact with the absorbing liquid. Since the solubility of propylene in the absorbing solution (silver nitrate aqueous solution) is considerably larger than the solubility of propane, propylene in the raw material gas is preferentially absorbed by the absorbing solution.

Here, with respect to the absorbing solution (silver nitrate aqueous solution) in the rotor 1, a higher concentration is preferable because the amount of propylene absorbed per unit volume / unit time increases. From a practical point of view, the concentration of the aqueous solution of silver nitrate, for example, be in the range of 1~8mol / dm ^3, more preferably a 3~5mol / dm ^3. As for the temperature of the absorbing solution (silver nitrate aqueous solution), the lower the temperature, the more the amount of gas (propylene) absorbed, which is advantageous. The temperature of the absorbent is, for example, in the range of 0 to 60 ° C, and more preferably 0 to 40 ° C. Further, heat is generated by absorption of propylene and the temperature of the absorbing liquid tends to increase. However, the absorbing liquid can be maintained at a desired temperature by the temperature adjusting means attached to the support 2.

  As for the internal gas pressure of the rotor 1, a higher pressure within a certain range is preferable because the amount of propylene absorbed increases. From a practical point of view, the internal gas pressure of the rotor 1 in the absorption process is, for example, 0.1 to 0.8 MPa (gauge pressure).

  Here, a centrifugal acceleration proportional to the distance from the rotation axis O1 acts on the absorbing liquid. For example, when the acceleration of gravity is expressed in 1 G, when the rotor 1 is rotated at 20 revolutions per second, a centrifugal acceleration of about 160 G is applied at a distance of 10 cm from the rotation axis O1, and the rotor 1 is rotated at 50 revolutions per second. In this case, a centrifugal acceleration as large as about 2000 G is applied when the distance from the rotation axis O1 is 20 cm.

  Thus, by applying a centrifugal force to the absorbing liquid, even when the gas pressure in contact with the liquid surface is low, the pressure applied to the absorbing liquid is increased. As the distance from the rotational axis O1 increases, the pressure applied to the interior of the absorbent is increased, the solubility of propylene gas increases, and the amount of propylene absorbed per unit volume of the absorbent increases.

  When propylene is dissolved in a silver nitrate aqueous solution as in the present embodiment, it depends on the concentration of the silver nitrate aqueous solution, the internal gas pressure of the rotor 1, the rotational speed of the rotor 1, etc., but reaches a saturation state in about several minutes. . At this time, for the gas (non-absorbed gas) that is not absorbed by the absorbing liquid in the space portion of the rotor 1, the propane concentration is high while the propylene concentration is lower than the raw material gas.

  In this way, in the rotor 1, when the raw material gas comes into contact with the absorbing liquid on which the centrifugal force acts, propylene in the raw material gas is efficiently absorbed by the absorbing liquid. That is, in the rotor 1, the absorption step referred to in the present invention is executed.

  Next, propylene is regenerated and recovered from the absorbent. At this time, the switching valve 5 is switched to a state in which the pipes L2 and L4 flow. Here, prior to the recovery of propylene, the gas in the space of the rotor 1 is discharged. Specifically, the valve 11 is closed and the valve 12 is opened, and the initial gas derived from the rotor 1 (mainly non-absorbed gas in the space portion of the rotor 1) is supplied to the pipes L2 to L5 and the gas discharge port. 8 is discharged out of the system through 8 (discharge process). Since the non-absorbed gas has a higher propane concentration than the raw material gas, it is preferable to discharge the non-absorbed gas without collecting it in order to increase the propylene purity of the purified gas described later. When the discharge of the non-absorbed gas is completed, the valve 12 is closed and the valve 11 is opened.

  The regeneration of propylene is performed by reducing the solubility of propylene in the absorbing solution. As a method for reducing the solubility of propylene, for example, the pressure in the rotor 1 is reduced. When the pressure inside the rotor 1 is reduced while keeping the number of rotations of the rotor 1 constant, a gas component escapes from the absorbing liquid. In a place where the liquid depth is deep (in other words, a place close to the side wall 1a, that is, a place away from the rotation axis O1), a sufficient pressure is applied, so gas generation mainly occurs in the vicinity of the liquid surface. In this method, the amount of regenerated gas is determined by the relationship between pressure and solubility. About the internal gas pressure of the rotor 1 in a collection | recovery process, -0.09-0.3MPa (gauge pressure) is preferable, and 0-0.3MPa (gauge pressure) is more preferable.

  At this time, even if mist is generated accompanying the regeneration gas from the liquid surface of the absorbing liquid, the mist is subjected to a large acceleration and is struck against the liquid surface, and is quickly taken into the absorbing liquid. Therefore, according to this method, generation | occurrence | production of mist can be suppressed effectively. In this way, a regeneration gas (high purity propylene gas) substantially free of mist components is obtained. The mist content in the regeneration gas can be confirmed, for example, by measuring the silver content (silver ion concentration) in the regeneration gas. For example, when the rotational speed of the rotor 1 is 10 revolutions or more per second, the silver ion concentration in the regeneration gas is 1 ppm or less, and the mist component is significantly removed.

  Another method for reducing the solubility of propylene includes, for example, reducing the rotational speed of the rotor 1 (decreasing the rotational speed of the rotor 1). When the rotational speed of the rotor 1 is decelerated, the pressure applied to the absorbing liquid is reduced as a whole, so that the gas solubility decreases in any part of the absorbing liquid. In this method, the amount of regenerated gas is determined by the relationship between pressure and solubility. Further, even if mist is generated accompanying the regeneration gas, the mist is quickly taken into the absorbing liquid for the above-described reason. In this way, a regeneration gas (high purity propylene gas) substantially free of mist components is obtained.

  Yet another method for reducing the solubility of propylene is to increase the temperature of the absorbing solution. If only the temperature of the absorbing liquid is increased without changing the rotation speed of the rotor 1, the solubility of the gas will decrease in any part of the absorbing liquid. In this method, the amount of regenerated gas is determined by the relationship between temperature and solubility. The temperature of the absorbing liquid is, for example, in the range of 10 to 70 ° C, and more preferably 20 to 70 ° C. Further, even if mist is generated accompanying the regeneration gas, the mist is quickly taken into the absorbing liquid for the above-described reason. In this way, a regeneration gas (high purity propylene gas) substantially free of mist components is obtained. Note that the above three types of regeneration methods (decompression in the rotor 1, increase in the temperature of the absorbing liquid, and decrease in the rotational speed of the rotor 1) can be executed in combination of two or more of them.

  In this manner, in the rotor 1, propylene is regenerated from the absorbing liquid by reducing the solubility of the dissolved gas (propylene) in the absorbing liquid (silver nitrate aqueous solution). Then, the regeneration gas is recovered as purified gas through the pipes L2 to L4 and the gas recovery port 7. That is, in the rotor 1, the recovery process referred to in the present invention is executed.

  In the present embodiment, for example, a cycle including the above-described absorption process, discharge process, and recovery process is repeated. In this case, when the raw material gas is absorbed again into the absorbing liquid after the regeneration operation (recovery step) and the gas is regenerated from the absorbing liquid, the high-purity propylene gas is dissolved in the absorbing liquid at the end of the previous regeneration. Since it remains in the state, it is possible to take out almost the same amount of gas as the newly absorbed gas by the regeneration operation.

  According to the present embodiment, by adopting a unique method of absorbing the raw material gas and performing regeneration or recovery of the gas while applying a centrifugal force to the absorption liquid, the demister is operated by a relatively simple operation by the absorption method. A purified gas (for example, high-purity propylene gas) substantially free of mist components can be obtained without using a dedicated device for removing mist such as a washing tower.

  It is also possible to combine a plurality of (for example, 2 to 4) rotors 1 described above. In this case, in a plurality of rotors 1, a cycle including an absorption process, a discharge process, and a recovery process is performed at different timings, so that a pressure swing adsorption method (PSA method), a temperature swing adsorption method (TSA method), etc. As in the gas purification method using the adsorbent, it is possible to obtain the purified gas continuously.

  FIG. 2 is a schematic configuration diagram of a gas purification device X2 according to the second embodiment of the present invention. The gas purification device X2 is different from the gas purification device X1 in that a plurality of baffle plates 1b are provided inside the rotor 1. In the present embodiment, as shown in FIGS. 2 and 3, for example, eight baffle plates 1b are evenly arranged in the circumferential direction of the side wall 1a of the rotor 1, and each baffle plate 1b is arranged in the radial direction. Extending inward.

  According to the configuration of the present embodiment, when the rotational speed of the rotor 1 is slightly changed in the absorption process, convection occurs in the region delimited by the baffle plate 1b for the absorption liquid, and the liquid surface portion is liquid by the convection. It is updated by the liquid that has moved from the deep part. As a result, the contact efficiency between the raw material gas and the absorbing liquid is improved, and the time required to absorb the raw material gas can be reduced as compared with the case where the baffle plate 1b is not provided.

  Also in the recovery process, if the rotational speed of the rotor 1 is slightly changed, convection occurs in the region separated by the baffle plate 1b for the absorbing liquid, and the liquid component moves from the deep liquid part to the vicinity of the liquid surface. As a result, the regeneration efficiency of the dissolved gas is improved. Thus, if the baffle plate 1b is provided, it is possible to increase the amount of absorbed gas and the amount of regenerated gas by minutely changing the rotational speed of the rotor 1, and as a result, purified gas. The generation efficiency of can be increased.

  As mentioned above, although embodiment of this invention was described, the range of this invention is not limited to above-described embodiment. The specific configuration of the purification apparatus for the target gas (for example, propylene gas) according to the present invention and the purification method for the target gas (for example, propylene gas) according to the present invention can be variously modified without departing from the spirit of the invention. It is.

  In the above embodiment, in the discharge process, the gas (non-adsorbed gas) in the space portion of the rotor 1 is discharged through the pipe L5 and the gas discharge port 8. Instead, the gas in the space portion is discharged. It is good also as a structure discharged | emitted via the piping connected to the lower part of the rotor 1. FIG. In this case, a method is adopted in which a part of the purified gas recovered in the recovery step is introduced into the rotor 1 through, for example, a backflow pipe, and the gas in the space portion of the rotor 1 is purged from the lower portion of the rotor 1. Can do. Such a configuration is preferable for increasing the recovery rate of the purified gas.

  In the above embodiment, the case where the target gas is propylene has been described as an example. However, the target gas is not limited to this, and may be a gas that is specifically absorbed by a predetermined absorbing liquid. If applicable. For example, if an alkanolamine aqueous solution is used as the absorbing solution, carbon dioxide as the target gas can be concentrated and purified. In this case, for example, in the utilization mode of continuously purifying and concentrating carbon dioxide from the flue gas of a power plant or in the aqualung using an oxygen cylinder, only the carbon dioxide generated by respiration is selectively removed and remains. It is possible to open many industrial fields of industrial use, such as a utilization mode in which oxygen is recycled. Furthermore, in the case of carbon dioxide, since the amount of absorption into water is large, it is possible to use only water as the absorbing solution.

  Next, the usefulness of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Example 1]
In this example, propylene was purified from a raw material gas using the gas purification apparatus X1 according to the first embodiment.

In this example, the rotor 1 was a cylindrical container having an inner diameter of 40 cm, a height of 30 cm, and an internal volume of 37.7 dm ³ . A 3 mol / dm ³ silver nitrate aqueous solution (specific gravity 1.4) was used as the absorbing solution, and the absorbing solution was received in the rotor 1 by 15 dm ³ . As the source gas, one having a propylene concentration of 99.5% and a propane concentration of 0.5% was used. In a state where the rotor 1 was rotated at 10 revolutions per second, the raw material gas was introduced into the rotor 1, and propylene in the raw material gas was absorbed into the absorbing liquid. The absorption operation was completed when the internal gas pressure of the rotor 1 finally reached 0.6 MPa (gauge pressure). The amount of propylene gas absorbed in the aqueous silver nitrate solution was 1.45 kg due to the change in the weight of the cylinder Y. In this example, the absorption operation took about 3 minutes. The temperature of the absorbent was 20 ° C. before the start of the absorption operation and 31 ° C. at the end of the absorption operation.

  Next, a part of propylene absorbed in the silver nitrate aqueous solution was regenerated and recovered while maintaining the rotation speed of the rotor 1. First, the pressure was reduced until the internal gas pressure of the rotor 1 became 0.5 MPa (gauge pressure). This operation took 1 minute, during which 0.06 kg of gas was recovered. The gas is a non-absorbing gas mainly in the space portion of the rotor 1, and propane as an impurity is contained in the gas at a relatively high concentration (10.3%).

  Subsequently, when the pressure inside the rotor 1 was reduced to 0.1 MPa (gauge pressure), 0.13 kg of purified gas was obtained. The propane concentration in the refined gas was 0.04%, and the propane concentration was greatly reduced as compared with the raw material gas supplied first (propane concentration was 0.5%). The silver ion concentration in the purified gas was 1 ppm or less. In this series of regeneration operations, the temperature of the absorbent changed from 31 ° C to 27 ° C. The time required for the reproduction operation was 10 minutes. In addition, although the trace amount water vapor | steam exists in the obtained refined gas, the quantity of said refined gas is the value which correct | amended the amount of water vapor | steam. In the following examples, the amount of purified gas is indicated by a value obtained by correcting the amount of water vapor.

[Example 2]
In the present example, propylene was purified from the raw material gas under the conditions different from those in Example 1, using the same gas purifier X1 as in Example 1. The absorption operation was performed in a state where the rotor 1 was rotated at 50 revolutions per second, and was completed when the internal gas pressure of the rotor 1 finally reached 0.1 MPa (gauge pressure). Other conditions of the absorption operation were the same as in Example 1. By this operation, 1.85 kg of propylene gas was absorbed into the absorbing solution. In this example, the temperature of the absorbing liquid became 27 ° C. at the end of the absorbing operation by cooling the support 2 with the temperature adjusting means.

  Next, a part of propylene absorbed in the silver nitrate aqueous solution was regenerated and recovered while maintaining the rotation speed of the rotor 1. In this example, first, when the temperature of the absorbing liquid was raised to 31 ° C., 0.12 kg of gas (mainly non-absorbing gas) was recovered. The gas contained propane at a relatively high concentration (6.9%).

  Subsequently, when the temperature of the absorption liquid was raised to 40 ° C., 0.76 kg of purified gas was obtained. The propane concentration in the refined gas was 0.04%, and the propane concentration was greatly reduced as compared with the raw material gas supplied first (propane concentration was 0.5%). The silver ion concentration in the purified gas was 1 ppm or less. The time required for this series of reproduction operations was 30 minutes.

Example 3
In the present example, propylene was purified from the raw material gas under the conditions different from those in Example 1, using the same gas purifier X1 as in Example 1. The conditions of the absorption operation were the same as in Example 2. In this embodiment, after the absorption operation is completed, 120 Ndm ³ of high-purity propylene gas having a propylene concentration of 99.99% is passed through the rotor 1 and the non-absorbed gas in the space portion of the rotor 1 is purged to the outside. did.

  Next, a part of propylene absorbed in the silver nitrate aqueous solution was regenerated and recovered while maintaining the rotation speed of the rotor 1. In this example, first, when the temperature of the absorbing solution was raised to 30 ° C., 0.10 kg of gas was recovered. The propane concentration in the gas was 0.08%.

  Subsequently, when the temperature of the absorption liquid was raised to 40 ° C., 0.78 kg of purified gas was obtained. The propane concentration in this refined gas was 0.03%, and the propane concentration was greatly reduced as compared to the raw material gas supplied first (propane concentration was 0.5%). The silver ion concentration in the purified gas was 1 ppm or less. The time required for this series of reproduction operations was 30 minutes.

Example 4
In this example, propylene was purified from a raw material gas using the gas purifier X2 according to the second embodiment. In the gas purification device X2, eight baffle plates 1b having a radial length of 4 cm are additionally provided for the same rotor 1 as in the first embodiment. In this example, the conditions of the absorption operation were the same as in Example 2. By this absorption operation, 1.88 kg of propylene gas was absorbed into the absorption liquid.

  Next, a part of propylene absorbed in the silver nitrate aqueous solution was regenerated and recovered while keeping the internal gas pressure of the rotor 1 and the temperature of the absorbing liquid constant. In this example, first, when the rotational speed of the rotor 1 was decreased from 50 to 20 revolutions per second, 0.12 kg of gas (mainly non-absorbed gas) was recovered. The gas contained propane at a relatively high concentration (7.2%).

  Subsequently, when the rotation speed of the rotor 1 was reduced to 10 rotations per second, 0.33 kg of purified gas was obtained. The propane concentration in this refined gas was 0.05%, and the propane concentration was greatly reduced as compared with the raw material gas supplied first (propane concentration 0.5%). The silver ion concentration in the purified gas was 1 ppm or less. The time required for this series of reproduction operations was 5 minutes.

Example 5
In the present embodiment, the rotation speed of the rotor 1 that has been regenerated in the fourth embodiment is again increased to 50 rotations per second, the raw material gas is reintroduced into the rotor 1, and the propylene in the raw material gas is absorbed into the absorbing liquid. I let you. The absorption operation was completed when the internal gas pressure of the rotor 1 finally reached 0.6 MPa (gauge pressure). From the change in the weight of the cylinder Y, the amount of propylene gas absorbed in the silver nitrate aqueous solution was 0.46 kg. This absorption operation took 2 minutes.

  Next, when the rotational speed of the rotor 1 was decreased from 50 to 20 revolutions per second in the same manner as in Example 4, 0.13 kg of gas was recovered. The propane concentration in the gas was 1.4%. Subsequently, when the rotation speed of the rotor 1 was reduced to 10 rotations per second, 0.34 kg of purified gas was obtained. The propane concentration in the purified gas was 0.02%, and the silver ion concentration in the purified gas was 1 ppm or less. The time required for this series of reproduction operations was 3 minutes.

Example 6
In the present example, carbon dioxide was purified from the raw material gas using the same gas purification apparatus X1 as in Example 1. A 20% ethanolamine aqueous solution was used as the absorbing solution, and the absorbing solution was received in the rotor 1 by 15 dm ³ . As the raw material gas, one having a carbon dioxide concentration of 20% and the remaining 80% consisting of air was used. The absorption operation was performed with the rotor 1 rotated at 50 revolutions per second, and was completed when the internal gas pressure of the rotor 1 finally reached 0.5 MPa (gauge pressure). Next, the non-absorbed gas (mainly air component) in the internal space of the rotor 1 is reduced by reducing the internal gas pressure of the rotor 1 to 0.1 MPa (gauge pressure) while maintaining the rotation speed of the rotor 1. Was discharged to the outside. Further, the same operation as described above (the absorption operation by introducing the raw material gas while increasing the pressure and the discharge operation of the non-absorbing gas while decreasing the pressure) was repeated nine times to absorb carbon dioxide in the absorption liquid. The carbon dioxide led to the rotor 1 by this series of operations was about 1.6 kg in terms of pure content.

  Next, when the rotational speed of the rotor 1 was decreased from 50 to 10 revolutions per second, 0.52 kg of purified gas was obtained. The carbon dioxide concentration in this refined gas was 98%, and carbon dioxide was concentrated and purified more efficiently than the raw material gas (carbon dioxide concentration 20%) supplied first.

Example 7
In this example, carbon dioxide was absorbed and removed from the raw material gas using the same gas purifier X2 as in Example 4. A 20% ethanolamine aqueous solution was used as the absorbing solution, and the absorbing solution was received in the rotor 1 by 15 dm ³ . As the source gas, one having an oxygen concentration of 96% and a carbon dioxide concentration of 4% was used. The absorption operation was performed with the rotor 1 rotated at 50 revolutions per second, and was completed when the internal gas pressure of the rotor 1 finally reached 0.5 MPa (gauge pressure). Next, while maintaining the rotational speed of the rotor 1, the internal gas pressure of the rotor 1 is reduced to 0.1 MPa (gauge pressure), whereby non-absorbed gas (mainly oxygen) in the internal space of the rotor 1 is reduced. Extracted outside. The carbon dioxide concentration in the extracted gas was 0.2%. Further, the same operation as described above (the absorption operation by introducing the raw material gas while increasing the pressure and the discharge operation of the non-absorbing gas while decreasing the pressure) was repeated nine times. The carbon dioxide concentration in the gas extracted at the 10th time was also 0.2%. Subsequently, when the rotation speed of the rotor 1 was reduced, it was confirmed that carbon dioxide absorbed from the absorbing solution (ethanolamine aqueous solution) could be recovered as a gas.

Example 8
In this example, propylene was purified from the raw material gas using the same gas purification apparatus X1 as in Example 1. A liquid obtained by dissolving silver borohydride at a concentration of 25% in 1-butyl-3-methylimidazolium which is an ionic liquid was used as the absorbing liquid, and the absorbing liquid was received in the rotor 1 by 15 dm ³ . As the source gas, one having a propylene concentration of 99.5% and a propane concentration of 0.5% was used. The absorption operation was performed in a state where the rotor 1 was rotated at 50 revolutions per second, and was completed when the internal gas pressure of the rotor 1 finally reached 0.6 MPa (gauge pressure). The amount of propylene gas absorbed in the absorbing liquid was 1.38 kg due to the change in the weight of the cylinder Y. The temperature of the absorption liquid was 22 ° C. before the start of the absorption operation and 29 ° C. at the end of the absorption operation.

  Next, a part of the propylene absorbed in the absorbing liquid was regenerated and recovered while maintaining the internal gas pressure of the rotor 1 and the temperature of the absorbing liquid constant. In this example, first, when the rotational speed of the rotor 1 was reduced from 50 to 20 revolutions per second, 0.08 kg of gas (mainly non-absorbed gas) was recovered. The gas contained propane at a relatively high concentration (5.6%).

  Subsequently, when the rotation speed of the rotor 1 was reduced to 10 rotations per second, 0.27 kg of purified gas was obtained. The propane concentration in the refined gas was 0.06%, and the propane concentration was greatly reduced as compared with the raw material gas supplied first (propane concentration was 0.5%). In the present embodiment, since the ionic liquid is used as a solvent, the purified gas obtained does not substantially contain water vapor.

[Comparative Example 1]
In this comparative example, propylene was purified from the raw material gas using the same gas purification apparatus X1 as in Example 1. The absorption operation was performed with the rotor 1 stopped, and ended when the internal gas pressure of the rotor 1 finally reached 0.6 MPa (gauge pressure). Other conditions of the absorption operation were the same as in Example 1. By this operation, 0.93 kg of propylene gas was absorbed into the absorbing solution. The temperature of the absorbent was 20 ° C. before the start of the absorption operation and 27 ° C. at the end of the absorption operation.

  Next, with the rotor 1 stopped, a part of propylene absorbed in the silver nitrate aqueous solution was regenerated and recovered. First, the pressure was reduced until the internal gas pressure of the rotor 1 became 0.5 MPa (gauge pressure). This operation took 1 minute, during which 0.04 kg of gas was recovered. The gas is a non-absorbing gas mainly in the space portion of the rotor 1, and propane as an impurity is contained in the gas at a relatively high concentration (6.6%).

  Subsequently, when the pressure inside the rotor 1 was reduced to 0.1 MPa (gauge pressure), 0.09 kg of purified gas was obtained. The propane concentration in this refined gas was 0.14%, and the propane concentration was greatly reduced as compared to the raw material gas supplied first (propane concentration 0.5%). The silver ion concentration in the purified gas was 8 ppm. In this series of regeneration operations, the temperature of the absorbent changed from 27 ° C to 25 ° C. The time required for the reproduction operation was 10 minutes.

[Comparative Example 2]
In this example, propylene was purified from the raw material gas using the same gas purification apparatus X1 as in Example 1. The absorption operation was performed with the rotor 1 stopped, and was completed when the internal gas pressure of the rotor 1 finally reached 0.1 MPa (gauge pressure). Other conditions of the absorption operation were the same as in Example 1. By this operation, 0.43 kg of propylene gas was absorbed into the absorption liquid. In this comparative example, the temperature of the absorbing liquid was 24 ° C. at the end of the absorbing operation by cooling the support 2 with the temperature adjusting means.

  Next, with the rotor 1 stopped, a part of propylene absorbed in the silver nitrate aqueous solution was regenerated and recovered. First, when the temperature of the absorbing liquid was raised to 31 ° C., 0.03 kg of gas (mainly non-absorbing gas) was recovered. The gas contained propane at a relatively high concentration (1.4%).

  Subsequently, when the temperature of the absorption liquid was raised to 40 ° C., 0.12 kg of purified gas was obtained. The propane concentration in this refined gas was 0.09%, and the propane concentration was greatly reduced as compared to the initially supplied raw material gas (propane concentration was 0.5%). The silver ion concentration in the purified gas was 5 ppm. The time required for this series of reproduction operations was 30 minutes.

  As can be understood by comparing Examples 1 and 2 and Comparative Examples 1 and 2 shown in Table 1, in Comparative Examples 1 and 2, the concentration of silver ions in the purified gas is high, and a large amount of mist components are generated during regeneration. On the other hand, in Examples 1 and 2, the silver ion concentration in the purified gas is 1 ppm or less, and the mist component can be significantly removed by regenerating the gas while applying a centrifugal force to the absorbing solution.

It is a schematic block diagram of the gas purification apparatus which concerns on the 1st Embodiment of this invention. It is a schematic block diagram of the gas purification apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing which follows the III-III line of FIG.

Explanation of symbols

X1, X2 gas purification equipment (target gas purification equipment)
Y cylinder 1 rotor 1a side wall 1b baffle plate 2 support 3 drive unit (rotation drive means)
4 Pressure regulator 5 Switching valve 6 Rotary joint 7 Gas recovery port 8 Gas exhaust ports L1 to L5 Piping O1 Rotation axis

Claims (8)

A method for purifying a target gas from a source gas containing a target gas and an unnecessary gas using an absorbing liquid that preferentially absorbs the target gas,
The rotor is made to be rotatable around a predetermined axis, and the absorbing liquid is received. The rotor is rotated at a first rotational speed to apply centrifugal force to the absorbing liquid, and the source gas is introduced into the rotor. An absorption step of preferentially absorbing the target gas in the raw material gas into the absorption liquid under a first temperature and a first pressure;
A recovery step of regenerating and recovering a gas component from the absorbing liquid under a second temperature and a second pressure while rotating the rotor at a second rotation speed and applying a centrifugal force to the absorbing liquid; A method for purifying a target gas, comprising:   The method for purifying a target gas according to claim 1, wherein the second pressure is lower than the first pressure.   The method for purifying a target gas according to claim 1 or 2, wherein the second temperature is higher than the first temperature.   The method for purifying a target gas according to any one of claims 1 to 3, wherein the second rotation speed is lower than the first rotation speed.   The object according to any one of claims 1 to 4, further comprising a discharge step of discharging the gas in the space portion of the rotor from the rotor that has finished the absorption step between the absorption step and the recovery step. Gas purification method.   The method for purifying a target gas according to claim 5, wherein in the discharge step, a part of the gas recovered in the recovery step is introduced into the rotor. An apparatus for purifying a target gas from a source gas containing a target gas and an unnecessary gas using an absorbing liquid that preferentially absorbs the target gas,
A rotor capable of rotating around a predetermined axis, and a rotor for receiving the absorbing liquid;
Raw material gas introduction means for introducing the raw material gas into the rotor;
Regeneration gas recovery means for recovering regeneration gas from the rotor;
Rotation driving means for rotating the rotor;
Temperature adjusting means for adjusting the temperature in the rotor;
And a pressure adjusting means for adjusting the pressure in the rotor.   The target gas purification device according to claim 7, wherein the rotor is provided with a baffle plate that extends inwardly from an inner surface of a side wall of the rotor.

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