JP4687184B2 - Method and apparatus for purifying mixed gas containing acid gas - Google Patents

Description

The present invention uses an absorbing liquid composed of an organic solvent or the like, an acidic gas such as CO ₂ , H ₂ S, COS, SO ₂ , SO ₃ , NO ₂ , CS ₂ , HCN, NH ₃ , mercaptan, and H _2. , CH ₄ , CO, O ₂ , N ₂ , a gas purification method for separating and recovering the acidic gas directly in a liquid state from a mixed gas containing a non-acidic gas such as a hydrocarbon compound having 2 to 10 carbon atoms, and It relates to the device and. In more detail, acid gas contained in synthesis gas, natural gas, etc. by gasification, reforming or partial oxidation of fossil fuel, and acid gas contained in exhaust gas from thermal power plant, cement plant, steel plant, chemical plant, etc. It relates to the purification method and equipment of the gas separated and collected directly in a liquid state. Further, the present invention relates to purification of hydrogen gas supplied to a hydrogen station or a fuel cell vehicle and separation and recovery of liquid CO ₂ .

Conventionally, when refining natural gas, refinery gas, ammonia synthesis gas, etc., acidic gas such as CO ₂ is separated and recovered, and this separation and recovery method includes a method of absorbing acidic gas, a method of distilling mixed gas And a method of adsorbing an acid gas, a method of separating a mixed gas by membrane separation, and a method of combining these methods. Of these, the lectizol process and the methyldiethylamine process (hereinafter referred to as MDEA process) are industrially frequently used methods (see, for example, Non-Patent Document 1).

The lectisol process is a physical absorption process, using methanol as an absorption liquid, such as CO ₂ contained in various gases such as synthesis gas by fossil fuel gasification, reforming or partial oxidation, ammonia synthesis gas, natural gas, etc. This is a method for absorbing and separating acidic gas. The absorption temperature of the acid gas is set in the range of −10 to −75 ° C., and the absorption pressure is set in the range of 7 to 8 MPa. This lectisol process (physical absorption process) has a feature that the regenerative energy of the absorbing solution is less than that of the MDEA process (chemical absorption process).
In this lectisol process, the absorption mechanism is based on the dissolution of the gas in the absorption liquid, so that the dissolved amount of the acidic gas is proportional to the acidic gas partial pressure in the absorption tower. For this reason, the acid gas in the mixed gas is separated by the difference in the partial pressure of the acid gas in the absorption tower and the regeneration tower. Further, methanol is inexpensive and the absorption capacity for acid gas is 3 to 6 times the absorption capacity for acid gas in other physical absorption processes, so that a large amount of acid gas can be treated under high pressure by physical absorption.

On the other hand, the MDEA process is a chemical absorption process, and a 30% by weight aqueous solution of tertiary amine methyldiethylamine is used alone or in combination with an activator, and is contained in various gases such as exhaust gas from combustion of fossil fuel and natural gas. This is a method for absorbing and separating acidic gas. In addition, the absorption temperature of acidic gas is set to the range of 30-60 degreeC, and the absorption pressure is set to the range of 2-3 MPa.
In the MDEA process, the absorption mechanism is a reversible reaction between an acidic gas and an absorbing liquid, and a compound is formed at a low temperature and high pressure (the absorption liquid absorbs the acidic gas in the absorption tower). Decomposes into gas and absorption liquid (the absorption liquid proceeds in the direction of releasing acid gas in the regeneration tower). The MDEA process is characterized in that the regeneration energy of the absorbing solution is as low as 1/7 to 1/2 that of other chemical absorption processes, and the absorption capacity of acid gas is high.
Editor: Japan Petroleum Institute, edited by Kodansha Scientific Co., Ltd., “Oil Refinery Process”, Kodansha Co., Ltd., May 1998, p. 360-361)

However, in the conventional lectizol process and MDEA process shown in the above-mentioned Non-Patent Document 1, since the absorption amount of the acidic gas per unit volume of the absorption liquid is small, the circulation amount and the circulation energy of the absorption liquid are large, and the apparatus is Since the distillation tower is increased in size and the absorption liquid is regenerated, the regeneration process is complicated, and since the regeneration is performed at a higher temperature, there is a problem in that much regeneration energy is used.
Further, in the above-described conventional non-patent document 1, in the rectizol process, in order to suppress methanol loss and increase the amount of acid gas absorbed per unit volume of the absorbing solution, the absorption temperature must be set low. In addition, since a refrigerating machine is required and the absorption liquid has a vapor pressure, the absorption loss of the absorption liquid is large, and when the acidic gas is CO ₂ , the specific gravity of methanol (absorption liquid) is the specific gravity of the liquid CO ₂ . Since there was almost no change, phase separation / separation by specific gravity could not be performed, and CO ₂ could not be separated and recovered in a liquid state.
Moreover, in the lectizol process and MDEA process shown in the above-mentioned conventional non-patent document 1, a small amount of absorption liquid remains in the separated and collected acid gas. For example, the acid gas is CO ₂ used for food addition. In some cases, high-purity CO ₂ having a purity of 99.99% by volume or more cannot be obtained, and there is a problem that further purification is required.
Furthermore, in the MDEA process shown in the above-mentioned conventional Non-Patent Document 1, since it is chemical absorption, the absorption liquid may deteriorate, and the absorption liquid is regenerated under low pressure and high temperature conditions to separate and recover the acid gas. For this reason, there is a problem that the acidic gas cannot be separated and recovered in a liquid state.

The first object of the present invention is to separate and recover the acid gas directly from the mixed gas in a liquid state with high efficiency and low cost, to increase the amount of the acid gas absorbed per unit volume of the absorbing liquid, and to further circulate the absorbing liquid. The amount of gas can be reduced and the circulation energy can be saved.In other words, by absorbing the acid gas from the mixed gas near room temperature, the regeneration of the absorbing liquid and the recovery of the liquid acidic gas can be easily and simultaneously realized, thereby saving energy. Another object of the present invention is to provide a method for purifying a mixed gas containing acidic gas and an apparatus for the same, which can separate and recover the acidic gas directly in a liquid state at low cost.
The second object of the present invention is to use an absorbing solution having a low vapor pressure, so that the absorbing solution can be regenerated relatively easily and at low cost, and the absorbing solution can be regenerated at a temperature lower than that of the conventional method. An object of the present invention is to provide a method for purifying a mixed gas containing an acidic gas and an apparatus therefor that can reduce the regenerative energy.
The third object of the present invention is to reduce the evaporation loss of the absorbing liquid by using the absorbing liquid having a low vapor pressure, and the absorbing liquid does not remain in the separated and recovered CO ₂ gas. Another object of the present invention is to provide a method for purifying a mixed gas containing an acid gas and an apparatus thereof, which can easily produce the CO ₂ gas.
The fourth object of the present invention is that CO ₂ can be efficiently recovered in a liquid state, the process can be simplified as compared with the conventional method, and there is no significant fluctuation in temperature and pressure during the entire process. By returning to the absorption tower with high pressure, the circulating energy of the absorbing liquid can be reduced, and by eliminating the energy to regenerate the absorbing liquid, energy saving can be achieved. The object is to provide a purification method and an apparatus therefor.
The fifth object of the present invention is to absorb acidic gas at a temperature higher than room temperature, thereby eliminating the need for a refrigerator and refrigeration energy, and reducing the cost, energy saving, and downsizing. An object of the present invention is to provide a purification apparatus for a mixed gas containing

As shown in FIG. 1, the invention according to claim 1 is made of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin at the upper part of the absorption tower 13 maintained at a predetermined temperature and a predetermined pressure, respectively. An absorbing liquid 42 made of one or more polymers selected from the group is supplied, and one or more selected from the group consisting of CO ₂ , H ₂ S and COS are supplied to the lower part of the absorption tower 13. And a mixed gas containing one or more non-acidic gases selected from the group consisting of H ₂ , CH ₄ , CO, O ₂ and N ₂ are supplied to the absorbing liquid 42. , The acidic gas is absorbed in the absorbing liquid 42 to separate the non-acidic gas from the acidic gas, and the non-acidic gas is recovered from the absorption tower 13, while maintaining the predetermined pressure and the absorption tower 13. The separation regenerator 46 maintained at a temperature lower than the above temperature is supplied with an absorbing liquid that has absorbed the acidic gas, thereby liquefying the acidic gas and due to mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the absorbing liquid 42. Separating the liquid acid gas 41 from the absorbent 42 and recovering it from the separation / regenerator 46 and regenerating the absorbent 42; and supplying the regenerated absorbent 42 to the upper portion of the absorption tower 13; This is a method for purifying a mixed gas containing an acid gas.
In the gas purification method according to claim 1, the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin is formed on the upper portion of the absorption tower 13 maintained at a predetermined temperature and a predetermined pressure, respectively. When the absorbing liquid 42 made of one or more selected polymers is supplied and a mixed gas containing acidic gas and non-acidic gas is supplied to the lower part of the absorption tower 13, the mixed gas comes into contact with the absorbing liquid 42. Then, since the acidic gas is absorbed by the absorbing liquid 42, the acidic gas is separated into the non-acidic gas and the acidic gas, and the non-acidic gas is recovered from the absorption tower 13. Maintain the same pressure as the pressure in the absorption tower 13, a pressure slightly higher than the pressure in the absorption tower 13, or a pressure slightly lower than the pressure in the absorption tower 13 and a temperature lower than the temperature in the absorption tower 13. When the absorbing liquid 42 that has absorbed the acid gas is supplied to the separation / regenerator 46 that has been maintained, the acidic gas is liquefied by the separation / regenerator 46, and is absorbed by the mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the absorbing liquid 42. The liquid acidic gas 41 is separated from the liquid 42 and recovered from the separation regenerator 46, and the absorbing liquid 42 is regenerated and reused. That is, the solubility with respect to the acidic gas becomes very large under pressure and in a predetermined temperature range, and the acidic gas is liquefied under pressure and in a temperature range lower than the predetermined temperature range. By utilizing the property that the liquid acidic gas 41 is separated from the absorbing liquid 42 due to the insolubility and the specific gravity difference, the acidic gas is directly liquid instead of being recovered by pressurizing and cooling to a liquid after recovering the acidic gas as a gas. Since the recovery is performed in a state, the non-acidic gas and the liquid acidic gas 41 can be efficiently separated and recovered from the mixed gas.

The invention according to claim 3 is the invention according to claim 1, further comprising an acidic gas discharged from the absorption tower 13 and cooled to a temperature lower than the temperature in the absorption tower 13, as shown in FIG. Before the absorption liquid 42 is supplied to the separation / regenerator 46, it further includes a step of centrifugal separation or stirring.
In the gas purification method described in claim 3 , the acidic gas in the absorbing liquid 42 is liquefied by cooling the absorbing liquid 42 containing the acidic gas to a temperature lower than the temperature in the absorption tower 13. Since the liquid acidic gas 41 is dispersed in the absorption liquid 42, the absorption liquid 42 containing the liquid acidic gas 41 is quickly brought into the separation regenerator 46 by being centrifuged or stirred before being supplied to the separation regenerator 46. Ru is Bunsho in the liquid acid gas absorbing liquid.

The invention according to claim 4 is the invention according to claim 1, and as shown in FIG. 4, one or more selected from the group consisting of water, alcohols, ethers and phenols An additive 71 is added to the absorbing liquid 42.
In the gas purification method described in claim 4 , the viscosity of the absorbing liquid 42 can be reduced by adding the additive 71 to the absorbing liquid 42. As a result, the additive-containing absorption liquid 75 is supplied to the absorption tower 13, so that the additive-containing absorption liquid 75 can absorb the acidic gas in the absorption tower 13 without substantially reducing the ability of the acidic gas to be absorbed. The contained absorbent 75 flows smoothly, and the additive-containing absorbent 75 can be handled easily.
The invention according to claim 5 is the invention according to claim 1, and as shown in FIG. 5, one or more additives 71 selected from the group consisting of water, alcohols and ethers. To the separation regenerator 46 and by adjusting the pressure and temperature in the separation regenerator 46 to separate the specific gravity difference into the liquid acidic gas 41 and the additive-containing absorbing liquid 75 in the separation regenerator 46; The additive-containing absorbent 75 discharged from the separator / regenerator 46 is supplied to the distillation separator 83 and the interior of the distillation separator 83 is heated to a predetermined temperature, whereby the additive in the additive-containing absorbent 75 is added. A step of distilling 71 from the absorbing liquid 42 by distillation.
In the gas purification method described in claim 5 , the additive 71 is supplied to the separation regenerator 46 together with the absorbing liquid 42 containing the liquid acidic gas 41 in a state where the pressure and temperature in the separation regenerator 46 are adjusted. Then, the mutual insolubility and specific gravity difference between the liquid acid gas 41 and the absorbing liquid 42 and the additive 71 having the mutual solubility with respect to the absorbing liquid 42 and the mutual insolubility with respect to the liquid acidic gas 41. By replacing the liquid acidic gas 41 dispersed in the absorbing liquid 42 by the addition with the additive 71, the liquid acidic gas 41 and the additive-containing absorbing liquid 75 are quickly separated. Next, when the additive-containing absorption liquid 75 discharged from the separation regenerator 46 is supplied to the distillation separator 83 with the inside of the distillation separator 83 heated to a predetermined temperature, the additive in the additive-containing absorption liquid 75 is supplied. 71 is separated from the absorbent 42 by distillation. As a result, the absorption liquid 42 from which the additive 71 has been removed is supplied to the absorption tower 13, so that the absorption gas can be absorbed by the absorption tower 13 without reducing the ability of the absorption liquid 42 to absorb the acid gas.

The invention according to claim 6 is the invention according to claim 1, characterized in that a flocculant is further added to the absorption liquid containing the liquid acidic gas in the separation regenerator.
In the gas purification method described in claim 6 , the liquid acidic gas (dispersed liquid) dispersed in the absorbing liquid by adding the flocculant to the absorbing liquid containing the liquid acidic gas in the separation regenerator. In the separation / regenerator, the flocculant-containing absorbent and the liquid acidic gas are quickly separated due to the difference in specific gravity between the flocculant-containing absorbent and the liquid acidic gas. Thereafter, if the flocculant-containing absorbing liquid is separated by distillation, the flocculant and the absorbing liquid are further separated.
The invention according to claim 7 is the invention according to claim 1 , and as shown in FIG. 6 , the liquid in the separation regenerator 46 in which the acidic gas is CO ₂ gas and the pressure is kept at 4 to 25 MPa. Water is supplied into the absorbing liquid 42 containing CO ₂ 41.
In the gas purification method described in claim 7 , water is introduced into the absorbing liquid 42 containing the liquid CO ₂ 41 in the separation regenerator 46 while the separation regenerator 46 is kept at a high pressure of 4 to 25 MPa. When supplied, a part of the liquid CO ₂ 41 is hydrated (solidified into a snow shape or a sherbet shape), and thus is separated into the liquid CO ₂ 41, the CO ₂ hydrate, and the absorbing liquid 42 in the separation regenerator 46.

In the invention according to claim 8 , as shown in FIG. 1, one or more acid gases selected from the group consisting of CO ₂ , H ₂ S and COS , and H ₂ , CH ₄ , CO, O A compressor 12 that compresses a mixed gas containing one or more non-acidic gases selected from the group consisting of ₂ and N _2, a compressed mixed gas is supplied to the lower part, and polyethylene glycol and polyvinyl are supplied to the upper part Absorbing liquid 42 made of one or more polymers selected from the group consisting of alcohol, polyether, polyester, polyalkane and polyolefin is supplied, and the mixed gas is brought into contact with absorbing liquid 42 to absorb the acid gas. Absorption tower 13 that absorbs liquid 42 to separate and recover non-acidic gas from acidic gas, cooler 47 that cools the absorbing liquid that has absorbed acidic gas, and cooled and absorbs acidic gas A separation regenerator 46 that is supplied with the collected liquid and separates and recovers the liquid acidic gas 41 from the absorbent 42 due to the mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the absorbent 42 and regenerates and reuses the absorbent 42. And a recirculation pump 17 that supplies the absorption liquid 42 discharged from the separation / regenerator 46 to the upper portion of the absorption tower 13 while maintaining a high pressure.
In the gas purifier according to claim 8 , the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin is formed on the upper portion of the absorption tower 13 maintained at a predetermined temperature and a predetermined pressure, respectively. When absorbing liquid 42 made of one or more selected polymers is supplied and mixed gas containing acidic gas and non-acidic gas is compressed and supplied to the lower part of absorption tower 13, absorption is performed. Since the mixed gas comes into contact with the liquid 42 and the acidic gas is absorbed by the absorbing liquid 42, the non-acidic gas is separated from the acidic gas and recovered from the absorption tower 13. The acidic gas was absorbed in the separation regenerator 46 maintained at the same pressure as the pressure in the absorption tower 13, a pressure slightly lower than the pressure in the absorption tower 13, or a pressure slightly higher than the pressure in the absorption tower 13. When the absorbing liquid is supplied after being cooled by the cooler 47, the acidic gas is liquefied by the separation regenerator 46, and the liquid acidic gas 41 is absorbed from the absorbing liquid 42 by the mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the absorbing liquid 42. Are separated and recovered from the separation regenerator 46. Further, the absorption liquid 42 regenerated by removing the liquid acid gas is supplied to the upper portion of the absorption tower 13 by the circulation pump 17 and reused.
The invention according to claim 9 is the invention according to claim 8 , wherein the absorption tower 13, the cooler 47, and the separation regenerator 46 are integrally provided as shown in FIG. 2. .
In the gas purification apparatus described in claim 9 , since the absorption tower 13, the cooler 47, and the separation regenerator 46 are integrally provided, the apparatus can be miniaturized.

The invention according to claim 10 is the invention according to claim 8 or 9 , wherein a centrifuge 48 or a stirrer is provided between the cooler 47 and the separation regenerator 46 as shown in FIG. It is characterized by that.
In the gas purifying apparatus according to claim 10 , the acidic gas in the absorbent 42 is liquefied by cooling the absorbent containing the acidic gas to a temperature lower than the temperature in the absorption tower 13 by the cooler 47. However, since the liquid acidic gas 41 is dispersed in the absorption liquid, the liquid acidic gas 41 is contained by centrifuging or stirring with the centrifuge 48 or the stirrer before being supplied to the separation regenerator 46. absorbent solution 42 is Ru is a rapidly liquid acid gas 41 in the separator regenerator 46 absorbing solution 42 bisection phase.

The invention according to an eleventh aspect is the invention according to any one of the eighth to tenth aspects, further comprising 1 selected from the group consisting of water, alcohols, ethers and phenols, as shown in FIG. The absorption liquid 42 which added the seed | species or the 2 or more types of additive 71 was stored, and the absorption liquid storage tank 72 for supplying this additive containing absorption liquid 75 to the absorption tower 13 was provided.
In the gas purification apparatus described in claim 11 , when the additive 71 is added to the absorbent 42 in the absorbent reservoir 72, the viscosity of the absorbent 42 can be reduced. As a result, the additive-containing absorption liquid 75 is supplied to the absorption tower 13, so that the additive-containing absorption liquid 75 can absorb the acidic gas in the absorption tower 13 without substantially reducing the ability of the acidic gas to be absorbed. The contained absorbent 75 flows smoothly, and the additive-containing absorbent 75 can be handled easily.
The invention according to claim 12 is the invention according to any one of claims 8 to 10, and as shown in FIG. 5, one or two selected from the group consisting of water, alcohols and ethers An additive storage tank 81 in which more than one type of additive 71 is stored and connected to the upper part of the separation regenerator 46, a pressure adjusting means 82 provided in the separation regenerator 46 for adjusting the pressure in the separation regenerator 46, and a separation A distillation separator 83 that stores the additive-containing absorbing liquid 75 that is connected to the lower part of the regenerator 46 and is separated in specific gravity by the separation regenerator 46 and moves to its lower phase, and the distillation separator 83 provided in the distillation separator 83. And heating means 84 for heating the interior to a predetermined temperature.
In the gas purifying apparatus described in claim 12 , the additive together with the absorbing liquid 42 containing the liquid acidic gas 41 in a state where the temperature and pressure in the separation regenerator 46 are adjusted by the cooler 47 and the pressure adjusting means 82. When 71 is supplied to the separation regenerator 46, the mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the absorbent 42, the mutual solubility with respect to the absorbent 42, and the mutual insolubility with respect to the liquid acidic gas 41 are obtained. By replacing the liquid acid gas 41 dispersed in the absorbing liquid 42 by the addition of the additive 71 having solubility with the additive 71, the liquid acid gas 41 is transferred to the upper phase of the separation regenerator 46 and the separation regenerator. The additive-containing absorption liquid 75 moves to the lower phase of 46, and the liquid acidic gas 41 and the additive-containing absorption liquid 75 are quickly separated. Next, when the additive-containing absorption liquid 75 discharged from the lower part of the separation regenerator 46 is supplied to the distillation separator 83 in a state where the inside of the distillation separator 83 is heated to a predetermined temperature by the heating means 84, the additive-containing absorption The additive 71 in the liquid 75 is distilled and separated from the absorbing liquid 42. As a result, the absorption liquid 42 from which the additive 71 has been removed is supplied to the absorption tower 13, so that the absorption gas can be absorbed by the absorption tower 13 without reducing the ability of the absorption liquid 42 to absorb the acid gas.

The invention according to claim 13 is the invention according to any one of claims 8 to 10 , wherein a flocculant tank for storing the flocculant is further connected to the separation regenerator.
In the gas purification apparatus described in claim 13 , the flocculant stored in the flocculant tank is dispersed in the absorbent by adding it to the absorbent containing the liquid acidic gas in the separation regenerator. Since liquid acidic gas (dispersed liquid) can be agglomerated, it is quickly separated into a flocculant-containing absorbing liquid and liquid acidic gas due to the difference in specific gravity between the flocculant-containing absorbing liquid and liquid acidic gas in the separation regenerator. . Thereafter, if the flocculant-containing absorbing liquid is separated by distillation, the flocculant and the absorbing liquid are further separated.
The invention according to claim 14 is the invention according to any one of claims 8 to 10 , and further, as shown in FIG. 6, the acidic gas is CO ₂ gas, and the pressure in the separation regenerator 46 is 4. A pressure adjusting means 82 for maintaining at ˜25 MPa is provided in the separation regenerator 46, and a water storage tank 91 in which water is stored is connected to the lower part of the separation regenerator 46.
Purification device gas claimed in claim 14, while maintaining the high pressure of 4~25MPa within separator regenerator 46 by the pressure adjustment means 82, liquid water from the water reservoir 91 within the separator regenerator 46 When fed into the absorbing solution 42 containing CO ₂ 41, since a part of the liquid CO ₂ 41 is hydrate of (solidified Yukijo or sherbet), liquid CO ₂ 41 and CO ₂ Hyde in the separator regenerator 46 Separated into rate and absorbent 42.

As shown in FIG. 7, the invention according to claim 15 reforms one or more fuels selected from the group consisting of desulfurized gasoline, naphtha, kerosene, methanol, dimethyl ether, liquefied petroleum gas, and natural gas. After the CO conversion and CO removal to form a mixed gas of H ₂ and CO ₂ , this mixed gas is used by using the gas purification method described in any one of claims 1 to 7, or in claims 8 to 14. Using the gas purifier described in any one of the above, the gas is separated and collected into H ₂ and CO _2, and the separated and collected H ₂ is supplied to the hydrogen station, and the separated and collected CO ₂ is adiabatically expanded. This is a system for producing dry ice.
In the system according to the fifteenth aspect , CO ₂ can be efficiently recovered while producing high-pressure H ₂ from various fuels.

As shown in FIG. 8, the invention according to claim 16 is mounted on an on-vehicle reforming type vehicle using a fuel cell as a drive source, and includes desulfurized gasoline, naphtha, kerosene, methanol, dimethyl ether, liquefied petroleum gas, and natural gas. 8. One or more fuels selected from the group consisting of reforming, CO conversion and CO removal on a vehicle to form a mixed gas of H ₂ and CO ₂ , and then the mixed gas is any one of claims 1 to 7 The gas purification method described in claim 1 or the gas purification device described in any one of claims 8 to 14 is used to separate and recover H ₂ and liquid CO _2, and the separated and recovered H _{2 2 is a system in} which ₂ is supplied to the fuel cell, and liquid CO ₂ is temporarily stored in the vehicle, and then taken down later.
In the system according to the sixteenth aspect of the present invention , the system can be miniaturized to the extent that it can be mounted on a vehicle, and liquid CO ₂ can be efficiently recovered while producing high-pressure H ₂ from various fuels. That is, a CO ₂ zero emission vehicle can be realized by collecting CO ₂ in liquid form and temporarily storing it on the vehicle.

As described above, according to the present invention, the upper part of the absorption tower maintained at a predetermined temperature and a predetermined pressure is selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin. In addition, an absorbing liquid composed of one or more kinds of polymers is supplied, a mixed gas containing an acidic gas and a non-acidic gas is supplied to the lower part of the absorption tower, and the mixed gas is brought into contact with the absorbing liquid so that the acidic gas is supplied. The absorption liquid that has absorbed the acid gas is supplied to the separation regenerator that is absorbed in the absorption liquid, maintained at a predetermined pressure, and maintained at a temperature lower than the temperature in the absorption tower. Can be recovered from the absorption tower, separated from the absorption liquid by the mutual insolubility and specific gravity difference between the liquid acid gas and the absorption liquid in the separation regenerator. Together can be recovered, can play absorbing liquid, by supplying the regenerated absorption liquid to the upper left absorption column of the high pressure, it can be reused absorption liquid. That is, the solubility in acidic gas becomes very large under pressure and in a predetermined temperature range, and the acidic gas is liquefied under pressure and in a temperature range lower than the predetermined temperature range. By utilizing the property that liquid acidic gas is separated from the absorbing liquid due to the difference in properties and specific gravity, the acidic gas is recovered directly in the liquid state rather than being pressurized and cooled to liquid after recovering the acidic gas as a gas. Therefore, the non-acid gas and the liquid acid gas can be separated and recovered from the mixed gas efficiently and at low cost. In addition, the process can be simplified compared to the prior art, there is no large fluctuation in temperature and pressure during the entire process, and the regeneration energy of the absorbent and the recompression energy when returning the regenerated absorbent to the absorption tower are unnecessary. Energy saving can be achieved.

In addition, if the absorption liquid containing acidic gas discharged from the absorption tower and cooled to a temperature lower than the temperature in the absorption tower is centrifuged or stirred before being supplied to the separation / regenerator, it is dispersed in the absorption liquid. Since the liquid acid gas that is present is substantially separated into the liquid acid gas and the absorption liquid before being supplied to the separation regenerator, the liquid acid gas and the absorption liquid can be quickly separated into phases in the separation regenerator. As a result, it is possible to shorten the phase separation time between the liquid acid gas and absorbing liquid, Ru can be recovered efficiently liquid acid gas.
Moreover, if the 1 type (s) or 2 or more types of additive chosen from the group which consists of water, alcohol, ethers, and phenols is added to an absorption liquid, the viscosity of an absorption liquid can be reduced. As a result, since the additive-containing absorption liquid is supplied to the absorption tower, the additive-containing absorption liquid can absorb the acid gas in the absorption tower without substantially reducing the ability to absorb the acid gas, and the additive-containing absorption liquid Flows smoothly and the handling of the additive-containing absorbent is facilitated.

In addition to supplying the above additives to the separation regenerator and adjusting the pressure and temperature in the separation regenerator, if the specific gravity difference separation between the liquid acid gas and the additive-containing absorbing liquid is performed in the separation regenerator, the absorption is achieved. By replacing the liquid acid gas dispersed in the absorbing liquid with an additive that is mutually soluble in the liquid and mutually insoluble in the liquid acid gas, The liquid acidic gas is transferred to the phase and the additive-containing absorbent is transferred to the lower phase of the separation regenerator, so that the liquid acidic gas and the additive-containing absorbent are rapidly separated. Then, with the inside of the distillation separator heated to a predetermined temperature, the additive-containing absorbent discharged from the separator / regenerator is supplied to the distillation separator to remove the additive in the additive-containing absorbent from the absorbent. If it separates by distillation, it can collect | recover in the state which isolate | separated the additive and the absorption liquid. As a result, the absorption liquid from which the additive has been removed is supplied to the absorption tower, and the additive from which the absorption liquid has been removed is supplied to the additive storage tank, so that the absorption liquid and the additive can be reused immediately, The absorbing gas can be absorbed by the absorption tower without reducing the ability of the absorbing solution to absorb the acid gas at all.
Moreover, if a flocculant is added to the absorption liquid containing the liquid acidic gas in the separation / regenerator, the liquid acidic gas (dispersed liquid) dispersed in the absorption liquid can be aggregated. As a result, the specific gravity difference separation between the liquid acidic gas and the flocculant-containing absorbing liquid can proceed promptly in the separation / regenerator, and then the flocculant-containing absorbing liquid can be separated by distillation. Can be further separated.
The acidic gas is CO ₂ gas, if supply water to the absorption solution containing liquid CO ₂ in the separator regenerator was maintained at a pressure of 4～25MPa, part of the liquid CO ₂ is hydrate of (snow Therefore, the liquid is separated into liquid CO ₂ , CO ₂ hydrate, and absorbent in the separation / regenerator. As a result, the liquid CO ₂ , CO ₂ hydrate, and absorption liquid can be separated and recovered by operations of solid-liquid separation and specific gravity difference separation. Therefore, liquid CO ₂ can be separated from the absorbing liquid more quickly.

The mixed gas is compressed by a compressor and supplied to the lower part of the absorption tower, and one or more kinds selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin from the upper part of the absorption tower or Supplying an absorption liquid consisting of two or more kinds of polymers, bringing the mixed gas into contact with the absorption liquid, absorbing the acidic gas into the absorption liquid, cooling the absorption liquid that has absorbed the acidic gas with a cooler, and separating and regenerating If it is supplied to the vessel, the non-acid gas can be separated from the acid gas by the absorption tower and recovered from the absorption tower, and the acid gas can be separated from the absorption liquid in the state of being liquefied by the separation regenerator and recovered from the separation regenerator, The absorption liquid can be regenerated and reused, and if the acidic gas is absorbed at a temperature above room temperature, a refrigerator can be eliminated.
If the absorption tower, the cooler, and the separation / regenerator are integrally provided, the apparatus can be reduced in size.
In addition, if a centrifuge or a stirrer is provided between the cooler and the separation regenerator, the absorption liquid containing the acidic gas is cooled to a temperature lower than the temperature in the absorption tower by the cooler. Since the acidic gas of the liquid is liquefied and dispersed in the absorbing liquid, the absorbing liquid containing the liquid acidic gas is centrifuged or stirred by a centrifuge or a stirrer, so that the liquid acidic gas is supplied before being supplied to the separation regenerator. It is almost separated into gas and absorbing liquid. As a result, phase separation between the liquid acidic gas and the absorbing liquid can be quickly performed in the separation / regenerator, so that the phase separation time between the liquid acidic gas and the absorbing liquid can be shortened and the liquid acidic gas can be efficiently recovered.

Also water, alcohols, absorption liquid obtained by adding one or more additives selected from the group consisting of ethers and phenols are stored for supplying the additive-containing absorbing solution to the absorption tower If an absorption liquid tank is provided, the viscosity of the absorption liquid can be reduced by adding an additive to the absorption liquid in the absorption liquid tank. As a result, it is possible to absorb the acid gas in the absorption tower with almost no decrease in the ability of the additive-containing absorbing liquid to absorb the acid gas, and the additive-containing absorbing liquid flows smoothly and the additive-containing absorbing liquid is easy to handle. become.

  Further, the additive storage tank in which the additive is stored is connected to the upper part of the separation regenerator, and a pressure adjusting means for adjusting the pressure in the separation regenerator is provided in the separation regenerator, and the specific gravity difference is separated by the separation regenerator. If the distillation separator storing the liquid transferred to the lower phase is connected to the lower part of the separation regenerator and the heating means for heating the inside of the distillation separator to a predetermined temperature is provided in the distillation separator, the condenser and the pressure adjustment When the additive is supplied to the separation regenerator together with the absorbing liquid containing the liquid acidic gas with the temperature and pressure in the separation regenerator adjusted by the means, the mutual insolubility and the specific gravity difference between the liquid acidic gas and the absorbing liquid, Separation and regenerator by replacing the liquid acid gas dispersed in the absorption liquid with an additive by adding an additive that is mutually soluble in the absorption liquid and mutually insoluble in the liquid acid gas Liquid acid gas migrates into the upper phase And migration additive-containing absorbing solution in the lower phase of the regenerator, a liquid acid gas and additive-containing absorption liquid is quickly separated. Then, when the additive-containing absorption liquid discharged from the lower part of the separation regenerator is supplied to the distillation separator with the inside of the distillation separator heated to a predetermined temperature by the heating means, the additive in the additive-containing absorption liquid is Distilled from the absorbent. As a result, since the additive and the absorption liquid can be recovered in a separated state, the absorption liquid from which the additive has been removed is supplied to the absorption tower, and the additive from which the absorption liquid has been removed is supplied to the additive storage tank Thus, the absorption liquid and the additive can be reused immediately, and the absorption gas can be absorbed in the absorption tower without reducing the ability of the absorption liquid to absorb the acid gas at all.

If the flocculant tank storing the flocculant is connected to the separation regenerator, the flocculant stored in the flocculant tank is added to the absorption liquid containing the liquid acidic gas in the separation regenerator, thereby Dispersed liquid acidic gas (dispersed liquid) can be aggregated. As a result, the specific gravity difference separation between the liquid acidic gas and the flocculant-containing absorbing liquid can proceed promptly in the separation / regenerator, and then the flocculant-containing absorbing liquid can be separated by distillation. Can be further separated.
If the acidic gas is CO ₂ gas, pressure adjusting means for maintaining the pressure in the separation regenerator at 4 to 25 MPa is provided in the separation regenerator, and the water storage tank in which water is stored is connected to the lower part of the separation regenerator. When water is supplied from the water storage tank into the absorption liquid containing liquid CO ₂ in the separation regenerator while the pressure in the separation regenerator is maintained at a high pressure of 4 to 25 MPa by the pressure adjusting means, part of the liquid CO ₂ Hydrates (solidifies into snow or sherbet). As a result, the liquid CO ₂ , CO ₂ hydrate, and absorption liquid can be separated and recovered by operations of solid-liquid separation and specific gravity difference separation. Therefore, liquid CO ₂ can be separated from the absorbing liquid more quickly.

The fuel is reformed, CO transformed and removed to form a mixed gas of H ₂ and CO ₂ , and then this mixed gas is separated and recovered into H ₂ and CO ₂ using the above gas purification method or gas purification device. If the separated and collected H ₂ is supplied to the hydrogen station and the separated and collected CO ₂ is adiabatically expanded to produce dry ice, high-pressure H ₂ is produced from various fuels, while CO ₂ is produced. ₂ can be recovered efficiently.
Further, the system is mounted on an on-vehicle reforming type vehicle using a fuel cell as a driving source, and after reforming the fuel on the vehicle, CO conversion and CO removal to form a mixed gas of H ₂ and CO ₂ , The mixed gas is separated and recovered into H ₂ and liquid CO ₂ by using the above gas purification method or gas purification apparatus, and the separated and recovered H ₂ is supplied to the fuel cell, and the liquid CO ₂ is temporarily recovered. If they are stored in the vehicle and then lowered together, they can be made small enough to be mounted on the vehicle, and CO ₂ can be efficiently recovered while producing high-pressure H ₂ from various fuels. That is, a CO ₂ zero emission vehicle can be realized by collecting CO ₂ in liquid form and temporarily storing it on the vehicle.

Next, the best mode for carrying out the present invention will be described with reference to the drawings.
<First Embodiment>
As shown in FIG. 1, the refining apparatus is supplied with a compressor 12 for compressing a mixed gas containing acidic gas and non-acidic gas, and a mixed gas that extends in the vertical direction and is compressed in the lower part and is absorbed in the upper part. An absorption tower 13 for supplying the liquid 42 and bringing the mixed gas into contact with the absorbing liquid 42 to absorb the acidic gas into the absorbing liquid 42 to separate and recover the non-acidic gas from the acidic gas; and the absorbing liquid that has absorbed the acidic gas The cooler 47 that cools the liquid 42 and the cooled absorption liquid 42 are supplied, and the liquid acid gas 41 is separated and recovered from the absorption liquid 42 by the mutual insolubility and specific gravity difference between the liquid acid gas 41 and the absorption liquid 42. In addition, a separation regenerator 46 that regenerates and reuses the absorption liquid 42 and a circulation pump 17 that supplies the regenerated absorption liquid 42 to the upper portion of the absorption tower 13 while maintaining a high pressure are provided.

The mixed gas is a fuel gas such as a synthetic gas obtained by gasification, reforming or partial oxidation of fossil fuel, natural gas, or exhaust gas discharged from a thermal power plant, a cement plant, a steel plant, a chemical plant, or the like. Acid gas is one or more gases selected from CO _2, H ₂ S and CO S or Ranaru group, non-acidic gas is H _2, CH _4, CO, O ₂ and N ₂ or al is one or more gases selected from the group consisting. Or absorbing liquid is a liquid other than an ionic liquid, specifically a one or both of the liquid organic solvent or water. As the organic solvent, it is preferable to use a polar organic solvent that has a large absorption capacity for acid gas, has a high density, a low vapor pressure, and does not dissolve much with a liquid acid gas (such as liquid CO ₂ ). Specifically, the organic solvent is preferably one or more polymers selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane, and polyolefin . On the other hand, water has a relatively large absorption capacity for acid gas, has a relatively large density, has a relatively low vapor pressure, and does not dissolve much with liquid acid gas (such as liquid CO ₂ ).

  The gas supply pipe 18 that connects the compressor 12 and the absorption tower 13 in communication is provided with a precooler 19, and the mixed gas is maintained at a predetermined temperature and a predetermined pressure by the compressor 12 and the precooler 19. In this state, it is supplied to the lower part of the absorption tower 13. Specifically, the temperature of the mixed gas supplied to the absorption tower 13, that is, the temperature in the absorption tower 13 is set to 0 to 100 ° C., preferably 30 to 50 ° C., and the mixed gas supplied to the absorption tower 13 The pressure, that is, the pressure in the absorption tower 13 is set to 4 to 25 MPa, preferably 6 to 10 MPa. Here, the temperature in the absorption tower 13 is limited to the range of 0 to 100 ° C. The reason is that a refrigerator is required if the temperature is less than 0 ° C., and if the temperature exceeds 100 ° C., the energy required for temperature increase increases and the acid gas This is because the amount absorbed by the absorbing liquid is reduced. Further, the pressure in the absorption tower 13 is limited to the range of 4 to 25 MPa. If the pressure is less than 4 MPa, the absorption amount of the acidic gas by the absorbing liquid decreases. This is because the cost increases. Although the absorption tower 13 may be an absorption drum, it is desirable to use a multistage absorption tower 13 in order to improve the absorption efficiency of acid gas.

The first communication pipe 21 that connects the lower end of the absorption tower 13 and the cooler 47 is provided with a pressure reducing valve 23, a flash drum 24, and a heat exchanger 26 in order from the absorption tower 13 side. The absorbing liquid containing acidic gas discharged from the lower end of the absorption tower 13 by the pressure reducing valve 23 and the flash drum 24 is depressurized by a predetermined pressure, for example, 0.1 to 0.5 MPa from the pressure in the absorption tower 13. This is for returning the _{H 2, CH 4, CO,} O 2, N only ₂ of which non-acidic gas by stripping absorption column 13 contained in the absorbing solution. The upper end of the flash drum 24 and the lower part of the absorption tower 13 are connected in communication by a first return pipe 31, and an auxiliary compressor 27 is provided in the first return pipe 31. The heat exchanger 26 is configured such that the high-temperature absorption liquid discharged from the lower end of the separation regenerator 46 gives heat to the low-temperature absorption liquid containing the acid gas discharged from the lower end of the flash drum 24. That is, the heat exchanger 26 is configured to heat the absorption liquid containing the acid gas discharged from the lower end of the flash drum 24 and to cool the high-temperature absorption liquid discharged from the lower end of the separation regenerator 46. The

On the other hand, the cooler 47 supplies the absorption liquid 42 containing the acidic gas to the separation / regenerator 46 in a state where it is kept substantially the same as the pressure in the absorption tower 13 and cooled to a temperature lower than the temperature in the absorption tower 13. Specifically, the pressure of the absorbing liquid 42 supplied to the separation regenerator 46, that is, the pressure in the separation regenerator 46 is the same pressure as the pressure in the absorption tower 13, and a pressure slightly higher than the pressure in the absorption tower 13. Alternatively, the pressure is set to 4 to 25 MPa, preferably 6 to 10 MPa, which is slightly lower than the pressure in the absorption tower 13, and the temperature of the absorbing liquid 42 supplied to the separation regenerator 46, that is, the temperature in the separation regenerator 46 is It is set to −30 to 30 ° C., preferably 0 to 20 ° C., lower than the temperature in the absorption tower 13. Here, the pressure in the separation regenerator 46 is 4 to 25 MPa, which is the same pressure as the pressure in the absorption tower 13, a pressure slightly higher than the pressure in the absorption tower 13, or a pressure slightly lower than the pressure in the absorption tower 13. The reason for limiting to this range is to liquefy the acid gas and to reduce the consumption of circulating energy of the absorbing liquid. The reason why the temperature in the separation regenerator 46 is limited to the range of −30 to 30 ° C. is that the cooling energy increases when the temperature is lower than −30 ° C., and the acidic gas such as CO ₂ becomes difficult to be liquefied when the temperature exceeds 30 ° C. It is. In addition, when making the pressure in the separation regenerator 46 higher than the pressure in the absorption tower 13, the pressure difference is preferably within a range of 0.1 to 3 MPa where the acidic gas can be liquefied by the temperature decrease. When making the pressure in the vessel 46 lower than the pressure in the absorption tower 13, the pressure difference is preferably within a range of 0.1 to 3 MPa which can liquefy the acidic gas due to the temperature decrease.

By adjusting the pressure and temperature in the separation / regenerator 46 in this way, the liquid acid gas 41 is absorbed from the absorbent 42 by the mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the absorbent 42 in the separation / regenerator 46. To be separated. Specifically, when the liquid acidic gas 41 is liquid CO ₂ and the pressure in the separation regenerator 46 is 8 MPa, the liquid CO ₂ becomes insoluble in the absorbent and the specific gravity of the absorbent is 1. Since the specific gravity of the liquid CO ₂ is 0.8, the absorption liquid sinks due to the mutual insolubility and specific gravity difference between the liquid CO ₂ and the absorption liquid, and the liquid CO ₂ floats and is separated. In addition, the heat exchanger 26 is configured such that the cooler absorbing liquid 42 discharged from the lower end of the separation regenerator 46 takes heat away from the lower temperature absorbing liquid containing the acidic gas discharged from the lower end of the flash drum 24. The That is, the heat exchanger 26 further cools the absorbing liquid 42 containing the acidic gas discharged from the lower end of the flash drum 24 and heats the lower-temperature absorbing liquid 42 discharged from the lower end of the separation / regenerator 46. Configured as follows. A centrifuge 48 is provided in the second communication pipe 22 between the cooler 47 and the separation regenerator 46. Further, the lower end of the separation regenerator 46 is connected to the upper part of the absorption tower 13 by a second return pipe 32, and the circulation pump 17 is provided in the second return pipe 32. Note that a stirrer may be provided instead of the centrifuge.

A method for purifying a gas using the purification apparatus configured as described above will be described.
Before supplying the mixed gas to the absorption tower 13, the circulation pump 17 and the auxiliary compressor 27 are operated in advance, and a coolant such as water, air, or ammonia is supplied to the precooler 19 and the cooler 47, and the centrifuge 48 is set. While rotating, the absorption liquid is circulated, and the temperature of the absorption liquid 42 supplied to the absorption tower 13 and the separation regenerator 46 is set to a predetermined temperature. First, the mixed gas is heated or cooled to a predetermined temperature by the compressor 12 and the precooler 19 and supplied to the lower part of the absorption tower 13 in a state where the pressure is increased to a predetermined pressure. As a result, the mixed gas comes into contact with the absorbing liquid 42 and the acidic gas is absorbed by the absorbing liquid 42, so that the non-acidic gas is separated from the acidic gas and recovered from the upper end of the absorption tower 13. When the pressure of the recovered non-acid gas is higher than the pressure required on the user side, for example, when the non-acid gas (mixed gas of H ₂ , CH ₄ , CO, O ₂ , N _2, etc. ) is used for a gas turbine. At present, since the pressure is about 3 MPa, the non-acidic gas is once decompressed using an expansion turbine or an adiabatic expansion valve. At this time, since the temperature of the non-acidic gas after the pressure reduction becomes low, this low-temperature non-acidic gas can be used as a refrigerant for the precooler 19 and the cooler 47. In addition, when an expansion turbine is used for decompression of the non-acidic gas, power can be generated by the expansion turbine, so that the electric power can be used for consumption in the place where the purification apparatus of this embodiment is installed.

On the other hand, the absorbing liquid containing a large amount of acidic gas and a small amount of non-acidic gas discharged from the lower end of the absorption tower 13 is decompressed by a predetermined pressure by the pressure reducing valve 23 and the flash drum 24. Only _{H 2, CH 4, CO,} O 2, N 2 of which non-acidic gas thereby contained in the absorption liquid is dissipated, is separated from the absorption liquid containing an acidic gas. The dissipated non-acid gas is discharged from the upper end of the flash drum 24, further pressurized by the auxiliary compressor 27, and returned to the absorption tower 13 again. The absorbing liquid 42 containing acid gas discharged from the lower end of the flash drum 24 is cooled by the regenerated absorbing liquid in the heat exchanger 26 and then further cooled by the cooler 47. At this time, the acidic gas in the absorption liquid is liquefied and dispersed in the absorption liquid 42. The absorbing liquid 42 containing the liquid acidic gas 41 is substantially separated into the liquid acidic gas 41 and the absorbing liquid 42 by the centrifugal separator 48 due to the specific gravity difference between the liquid acidic gas 41 and the absorbing liquid 42, and then supplied to the separation regenerator 46. Is done. Normally, the liquid acid gas 41 has a smaller specific gravity than the absorbing liquid 42, so that the liquid acid gas 41 moves away from the rotation center of the centrifuge 48, and the absorbing liquid 42 approaches the rotation center of the centrifuge 48. Move in the direction. That is, the absorption liquid 42 is kept almost the same as the pressure in the absorption tower 13 by the heat exchanger 26 and the cooler 47 and is made lower than the temperature in the absorption tower 13, whereby the gas in the absorption liquid 42 is liquefied. Further, it is supplied to the separation regenerator 46 in a state of being substantially separated into the liquid acidic gas 41 and the absorbing liquid 42 by the centrifugal separator 48. The absorbing liquid 42 containing the liquid acidic gas 41 supplied to the separation regenerator 46 in a state of being substantially separated into the liquid acidic gas 41 and the absorbing liquid 42 is the mutual insolubility and specific gravity of the liquid acidic gas 41 and the absorbing liquid 42. Due to the difference, the liquid acid gas 41 and the absorbing liquid 42 are quickly phase-separated. Usually, since the liquid acid gas 41 has a lower specific gravity than the absorbing liquid 42, the liquid acid gas 41 quickly floats and shifts to the upper phase, and the absorbing liquid 42 quickly sinks and shifts to the lower phase. As a result, the liquid acidic gas 41 is separated from the absorbing liquid 42 and efficiently recovered from the upper part of the separation regenerator 46 in a relatively short time. Further, the regenerated absorption liquid 42 that does not contain the acid gas discharged from the lower end of the separation regenerator 46 is conveyed by the circulation pump 17 and heated to a predetermined temperature by the heat exchanger 26, and then the upper part of the absorption tower 13. To be reused. When the liquid acidic gas 41 is liquid CO ₂ , dry ice (solid CO ₂ ) that can be sold as a product by adiabatically expanding a part or all of the recovered liquid CO ₂ by opening the pressure reducing valve. Can be manufactured.

<Second Embodiment>
FIG. 2 shows a second embodiment. 2, the same reference numerals as those in FIG. 1 denote the same components.
In this embodiment, the pressure reducing valve, the flash drum, the auxiliary compressor, and the heat exchanger of the first embodiment are not used, and the absorption tower 13, the cooler 47, the centrifuge 48, and the separation regenerator 46 are not used. They are integrally provided in a state of being arranged in the vertical direction from the top to the bottom in order. The configuration other than the above is the same as that of the first embodiment.
In the purification apparatus configured as described above, the absorption tower 13, the cooler 47, the centrifuge 48, and the separation regenerator 46 are integrally provided, so that the operation is the first implementation except that the apparatus can be reduced in size. Since it is substantially the same as the embodiment of FIG. When the liquid acidic gas 41 is liquid CO ₂ , dry ice (solid CO ₂ ) that can be sold as a product by adiabatically expanding a part or all of the recovered liquid CO ₂ by opening the pressure reducing valve. Can be manufactured.

<Fourth embodiment>
FIG. 4 shows a fourth embodiment. 4, the same reference numerals as those in FIG. 1 denote the same components.
In this embodiment, an absorption liquid storage tank 72 in which the absorption liquid 42 to which the additive 71 is added is stored. In the case where an organic solvent is used as the absorbing liquid, the additive 71 includes one or more additives selected from the group consisting of water, alcohols, ethers and phenols. On the other hand, when water is used as the absorbing liquid, the additive 71 may be one or more additives selected from the group consisting of alcohols, ethers and phenols. Specifically, examples of alcohols include methanol and ethanol, examples of ethers include dimethyl ether and ethyl ether, and examples of phenols include phenol and the like. These additives 71 hardly interfere with the ability of the absorbing liquid 42 to absorb the acidic gas. Moreover, 1 to 50 weight% of an additive is added to the absorption liquid 42 in the absorption liquid storage tank 72 with respect to 100 weight% of absorption liquid, Preferably 5 to 10 weight% is added. Here, the additive is limited to the range of 1 to 50% by weight. If the amount is less than 1% by weight, the effect of reducing the viscosity of the absorbing liquid 42 cannot be obtained so much. This is because it has an adverse effect on the absorption performance. In the absorption liquid storage tank 72, a stirrer 73 is provided in order to disperse the additive 71 uniformly in the absorption liquid 42. The lower part of the absorption liquid storage tank 72 is connected to the upper part of the absorption tower 13 by an absorption liquid supply pipe 74. Further, the absorption liquid supply pipe 74 includes an absorption liquid supply pump 76 that supplies the additive-containing absorption liquid 75 in the absorption liquid storage tank 72 to the upper portion of the absorption tower 13, and an on-off valve 77 that opens and closes the absorption liquid supply pipe 74. Is provided. The configuration other than the above is the same as that of the first embodiment.
A method for purifying a gas using the purification apparatus configured as described above will be described.
First, when the additive 71 is added to the absorbent 42 in the absorbent reservoir 72 and mixed by the stirrer 73, the additive 71 is dispersed in the absorbent 42 and the viscosity of the absorbent 42 decreases. Next, the opening / closing valve 77 is opened, and the additive-containing absorbing liquid 75 is supplied to the upper portion of the absorption tower 13 by the absorbing liquid supply pump 76, and then the opening / closing valve 77 is closed. Further, the additive-containing absorption liquid 75 is circulated between the absorption tower 13 and the separation regenerator 46 by the circulation pump 17 instead of the absorption liquid of the second embodiment. As a result, it is possible to absorb the acidic gas in the absorption tower 13 without substantially reducing the ability of the additive-containing absorbent 75 to absorb the acidic gas. Further, since the additive-containing absorbing liquid 75 having a low viscosity circulates smoothly between the absorption tower 13 and the separation regenerator 46, the handling of the absorbing liquid becomes easy. Since the operation other than the above is substantially the same as the operation of the first embodiment, repeated description will be omitted.

<Fifth embodiment>
FIG. 5 shows a fifth embodiment. 5, the same reference numerals as those in FIG. 4 denote the same components.
In this embodiment, an additive storage tank 81 in which the additive 71 is stored is connected to the upper part of the separation regenerator 46, a pressure adjusting means 82 is provided in the separation regenerator 46, and a distillation is performed at the lower part of the separation regenerator 82. A separator 83 is connected, and the distillation separator 83 is provided with heating means 84. When an organic solvent is used as the absorbent, the additive 71 includes one or more additives selected from the group consisting of water, alcohols and ethers, and water is used as the absorbent. In some cases, the additive 71 includes one or both of alcohols and ethers. The lower part of the distillation separator 83 is connected to the suction port of the circulation pump 17 by the second return pipe 32. The pressure in the separation regenerator 46 is adjusted to 4 to 25 MPa, preferably 6 to 10 MPa by the pressure adjusting means 82. The temperature in the distillation separator 83 is adjusted to 50 to 250 ° C., preferably 100 to 150 ° C. by the heating means 84. Here, the reason why the pressure in the separation regenerator 46 adjusted by the pressure adjusting means 82 is limited to the range of 4 to 25 MPa is that a gas phase may be generated if the pressure is less than 4 MPa. This is because the density of the liquid acidic gas 41 becomes higher and the density of the absorbing liquid 42 approaches. The reason why the temperature in the distillation separator 83 adjusted by the heating means 84 is limited to the range of 50 to 250 ° C. is that if the temperature is less than 50 ° C., the complete separation of the additive 71 is difficult. It is necessary. Further, a check valve 86 is provided in the second communication pipe 22 between the centrifuge 48 and the separation regenerator 46. The check valve 86 allows the flow of the additive-containing absorption liquid 75 from the centrifuge 48 to the separation regenerator 46 and allows the flow of the additive-containing absorption liquid 75 from the separation regenerator 46 to the centrifuge 48. Configured to block. The phenols of the sixth embodiment are excluded from the additive of the seventh embodiment because the boiling points of the phenols are high, and when they are separated by distillation operation, they are considerably heated (250 ° C. This is because complete separation cannot be achieved without heating. The configuration other than the above is the same as that of the fourth embodiment.
A method for purifying a gas using the purification apparatus configured as described above will be described.
Liquid acid gas in a state where the temperature in the separation regenerator 46 is adjusted to a range of 0 to 30 ° C. by the cooler 47 and the pressure in the separation regenerator 46 is adjusted to a range of 4 to 25 MPa by the pressure force adjusting means 82. When the additive 71 is supplied to the separator / regenerator 46 together with the absorbent 42 containing 41, the mutual insolubility and specific gravity difference between the liquid acidic gas 41 and the additive-containing absorbent 75 and the mutual solubility with respect to the absorbent 42 are obtained. The upper phase of the separator / regenerator 46 is obtained by replacing the liquid acid gas 41 dispersed in the absorption liquid 42 with the additive 71 by the addition of the additive 71 having the mutual insolubility with the liquid acid gas 41. Thus, the liquid acidic gas 41 moves to the lower phase and the additive-containing absorbing liquid 75 moves to the lower phase of the separation regenerator 46, so that the liquid acidic gas 41 and the additive-containing absorbing liquid 75 are quickly separated. Next, the additive-containing absorbing liquid 75 discharged from the lower part of the separation / regenerator 46 is distilled and separated while the distillation separator 83 is heated to a temperature of 50 to 250 ° C., preferably 100 to 150 ° C. by the heating means 84. When supplied to the vessel 83, the additive 71 in the additive-containing absorbent 75 is distilled and separated from the absorbent 42. As a result, since the additive 71 and the absorbing liquid 42 can be recovered in a separated state, the absorbing liquid 42 from which the additive 71 has been removed is supplied to the absorption tower 13, and the additive 71 from which the absorbing liquid 42 has been removed is the additive. The absorption liquid 42 and the additive 71 can be reused immediately after being supplied to the storage tank 81, and the absorption tower 13 can absorb the acid gas without reducing the ability of the absorption liquid 42 to absorb the acid gas at all. it can. Since the operation other than the above is substantially the same as the operation of the first embodiment, repeated description will be omitted.

<Sixth Embodiment>
FIG. 6 shows a sixth embodiment. 6, the same reference numerals as those in FIG. 5 denote the same components.
In this embodiment, the acidic gas is CO ₂ gas, and the pressure adjusting means 82 for maintaining the pressure in the separation regenerator 46 at 4 to 25 MPa, preferably 6 to 10 MPa is provided in the separation regenerator 46 to store water. The water storage tank 91 is connected to the lower part of the separation regenerator 46. In addition, a solid-liquid separator 92 is connected to the separation regenerator 46, and a sub-separation regenerator 93 is connected to the upper part of the solid-liquid separator 92. The lower part of the sub separation regenerator 93 is connected to the suction port of the circulation pump 17 by the second return pipe 32. Here, the reason why the pressure in the separation regenerator 46 adjusted by the pressure adjusting means 82 is limited to the range of 4 to 25 MPa is that if it is less than 4 MPa, it is difficult to generate CO ₂ hydrate, and if it exceeds 25 MPa, the equipment cost is high. This is because the density of the liquid CO ₂ 41 approaches the density of the absorbing liquid 42. Examples of the solid-liquid separator 92 include a filter and a centrifuge. The configuration other than the above is the same as that of the fifth embodiment.
A method for purifying a gas using the purification apparatus configured as described above will be described.
The inside of the separation regenerator 46 while maintaining the pressure of 4~25MPa by the pressure regulating means 82, it is supplied from the water storage tank 91 the water absorbing solution containing liquid CO ₂ in the separator regenerator 46, the liquid CO ₂ A part of hydrates, that is, solidifies in the shape of snow or sherbet. When the absorption liquid containing this CO ₂ hydrate and liquid CO ₂ is supplied to the solid-liquid separator 92, it is separated into CO ₂ hydrate, liquid CO ₂ and absorption liquid, and the CO ₂ hydrate is separated from the solid-liquid separator 92. It is discharged from the bottom. On the other hand, the solid-liquid is supplied and the separator liquid CO ₂ in 92 absorption liquid to the sub separation regenerator 93, by mutual infusible and specific gravity difference of the liquid CO ₂ 41 and the absorption liquid 42, the liquid CO ₂ 41 and absorbing solution 42. By generating the CO ₂ hydrate in this way, the liquid CO ₂ 41 can be separated from the absorbing liquid 42 more quickly. Since the operation other than the above is substantially the same as the operation of the first embodiment, repeated description will be omitted.

<Seventh embodiment>
FIG. 7 shows a seventh embodiment.
In this embodiment, after the fuel is reformed, CO converted and CO removed to form a mixed gas of H ₂ and CO ₂ , this mixed gas is used as the gas purification method of the first to sixth embodiments or Using one of the gas purifiers, H ₂ and CO ₂ are separated and recovered, and the separated and recovered H ₂ is supplied to the hydrogen station, and the separated and recovered CO ₂ is adiabatically expanded to dry ice ( It is configured to produce solid CO ₂ ). Examples of the fuel include one or more fuels selected from the group consisting of desulfurized gasoline, naphtha, kerosene, methanol, dimethyl ether, liquefied petroleum gas, and natural gas. The reforming of the fuel is steam reforming, partial oxidation, or supercritical water reforming, and the fuel is reformed into H ₂ and CO by the reforming. Also, most of CO is converted to CO ₂ by CO conversion, and a little remaining CO is removed by CO removal. The remaining mixed gas of H ₂ and CO ₂ is high pressure H ₂ and CO _{2 in a} gaseous state or a liquid state using either the gas purification method or the gas purifying apparatus of the first to sixth embodiments. Separated. Further, the high pressure H ₂ is supplied to the hydrogen station and becomes a fuel for a hydrogen fuel cell vehicle. On the other hand, when CO ₂ is recovered in a liquid state, dry ice that can be sold as a product can be manufactured by adiabatically expanding a part or all of the recovered liquid CO ₂ by opening the pressure reducing valve. When CO ₂ is recovered in a gaseous state, the recovered CO ₂ gas is pressurized to liquid CO ₂ , and then a part or all of the liquid CO ₂ is adiabatically expanded by opening the pressure reducing valve. Dry ice (solid CO ₂ ) that can be sold as a product can be manufactured.

<Eighth Embodiment>
FIG. 8 shows an eighth embodiment.
In this embodiment, after the fuel is reformed on the vehicle, CO conversion and CO removal are made into a mixed gas of H ₂ and CO ₂ , this mixed gas is mixed with the gas of the first to sixth embodiments. A system that separates and recovers H ₂ and CO ₂ using either a purification method or a gas purifier, and supplies the separated and recovered H ₂ to the fuel cell is improved on the vehicle using the fuel cell as a drive source. Installed in quality vehicles. Examples of the fuel include one or more fuels selected from the group consisting of desulfurized gasoline, naphtha, kerosene, methanol, dimethyl ether, liquefied petroleum gas, and natural gas. The reforming of the fuel is steam reforming, and the fuel is reformed into H ₂ and CO by the steam reforming. Also, most of CO is converted to CO ₂ by CO conversion, and a little remaining CO is removed by CO removal. And the remaining mixed gas of H ₂ and CO ₂ is separated into the high pressure H ₂ and liquid CO ₂ using any of the purification apparatus of the first to sixth purification process or gas embodiment of gas. Further, the high pressure H ₂ is supplied to the fuel cell, and the liquid CO ₂ is temporarily stored in the vehicle and later lowered together. As a result, liquid CO ₂ can be efficiently recovered while producing high-pressure H ₂ from various fuels. That is, a CO ₂ zero emission vehicle can be realized by collecting CO ₂ in liquid form and temporarily storing it on the vehicle.

Note that the flocculant may be added to the absorption liquid containing the liquid acidic gas in the separation regenerator. In this case, a flocculant tank storing the flocculant is connected to the separation regenerator. By adding the flocculant stored in the flocculant tank to the absorbing liquid containing the liquid acidic gas in the separation regenerator, the liquid acidic gas (dispersed liquid) dispersed in the absorbing liquid can be aggregated. Therefore, if the lower part of the separation regenerator is connected to the suction port of the circulation pump, the pressure in the separation regenerator is set to 4 to 25 MPa and the temperature is set to 0 to 30 ° C., the liquid acidity in the separation regenerator Since the specific gravity difference separation between the gas and the flocculant-containing absorbing liquid proceeds promptly, the gas is quickly separated into the liquid acidic gas and the flocculant-containing absorbing liquid, and the flocculant-containing absorbing liquid is supplied to the distillation separator. On the other hand, the lower part of the separation regenerator is connected to a distillation separator with a heating means, the lower part of the distillation separator is connected to the inlet of the circulation pump, and the upper part of the distillation separator is connected to the flocculant tank. Separation of specific gravity between the liquid acidic gas and the flocculant-containing absorbent proceeds rapidly in the regenerator, and the flocculant in the distillation separator is separated from the absorbent by distillation. The liquid is quickly separated from the liquid, and only the absorption liquid is supplied to the absorption tower.
Moreover, the purification process or purification system of the first to sixth embodiment, the high pressure gas source which is discharged from oil refineries and ammonia plants, high CO ₂ Steel exhaust gas (CO ₂ concentration: about 27%) and the fermentation Applying to low-pressure gas sources such as gases (CO ₂ concentration: about 30 to 40%), that is, supplying these gas sources to the absorption tower of the purification method or purification apparatus of the first to sixth embodiments. Thus, liquid CO ₂ or dry ice may be produced. Since the purification method or apparatus of the first to sixth embodiments basically uses a physical absorption method, it occupies 70 to 80% of the running cost of a conventional (existing) liquid CO ₂ production plant. The regeneration energy cost, the regeneration gas (CO ₂ ) compression cost, the regeneration gas (CO ₂ ) refrigerating cost, the regeneration absorbent recompression cost, and the like can be made almost unnecessary. As a result, for the liquid CO ₂ production facility that has been depreciated to some extent, it is replaced with the facility that employs the purification method or apparatus of the first to sixth embodiments rather than continuing to operate the existing facility. There is a merit in terms of cost.

Next, embodiments of the present invention will be described in detail.
<Example 1>
Commercially available primary polyethylene glycol having an average molecular weight of 200 was used as the absorbing solution. This absorbent was designated as Example 1.
<Test 1 and evaluation>
The absorption liquid of Example 1 was brought into contact with high-purity CO ₂ gas having a purity of 99.99% by volume. Specifically, the solubility of the CO ₂ gas in the absorbing solution was measured using a gas-liquid equilibrium measuring device. The measurement temperature was kept constant at 35 ° C., and the pressure was changed stepwise from atmospheric pressure to 0.5 MPa. From the amount of CO ₂ gas which has not been total and the absorption of CO ₂ gas as a source gas, to calculate the solubility of the absorption liquid CO ₂ gas, and the results are shown in Figure 9.
As is apparent from FIG. 9, it was found that the solubility of the CO ₂ gas in the absorbing liquid is large and increases as the pressure increases.

<Test 2 and evaluation>
Using the absorption liquid of Example 1, a gas-liquid equilibrium test with various gases (acid gases) of H ₂ S gas and COS gas was performed separately for each type of gas. The purity of the H ₂ S gas and the COS gas was as high as 99.9% by volume, respectively. Specifically, the solubility of the H ₂ S gas and the COS gas in the absorbing solution was measured using a high-pressure gas-liquid equilibrium measuring device. The measurement temperature was kept constant at 35 ° C., and the pressure was changed stepwise from atmospheric pressure to 0.25 MPa. From the amounts of various gases and the amounts of various gases that were not absorbed, the solubilities of H ₂ S gas and COS gas in the absorbing liquid were calculated, and the results are shown in FIG.
As is apparent from FIG. 10, it was found that the solubility of various gases of H ₂ S gas and COS gas in the absorbing liquid is very large and increases as the pressure increases.

<Test 3 and evaluation>
Using the absorption liquid of Example 1, a gas-liquid equilibrium test with various gases (non-acid gases) of H ₂ gas, CH ₄ gas, CO gas, and N ₂ gas was performed separately for each type of gas. It was. The purity of the H ₂ gas is 99.99% by volume or more, the purity of the CH ₄ gas is 99.97% by volume or more, the purity of the CO gas is 99.97% by volume or more, and the purity of the N ₂ gas Was 99.999 volume% or more. Specifically, using a high-pressure gas-liquid equilibrium measuring device, the solubility of the various gases of H ₂ gas, CH ₄ gas, CO gas, and N ₂ gas in the absorbing solution was measured. The measurement temperature was kept constant at 35 ° C., and the pressure was changed stepwise from atmospheric pressure to 0.5 MPa. The solubilities of H ₂ gas, CH ₄ gas, CO gas, and N ₂ gas in the absorbing solution were calculated from the amounts of various gases and the amounts of various gases that were not absorbed, and the results are shown in FIG. .
As is apparent from FIG. 11, it was found that the solubility of various gases of H ₂ gas, CH ₄ gas, CO gas, and N ₂ gas in the absorbing solution was very small and hardly absorbed.

<Test 4 and evaluation>
In order to confirm the degree of phase separation due to the mutual insolubility with liquid CO ₂ and the difference in specific gravity using the absorption liquid of Example 1, a high-pressure container (visible from the outside) set at a temperature of 20 ° C. and a pressure of 7 MPa. The absorption liquid and liquid CO ₂ were each injected into the transparent member. The injected absorbing liquid (specific gravity 1.13) and liquid CO ₂ (specific gravity 0.81) were in two phases due to mutual insolubility and specific gravity difference. Next, the absorbing liquid and liquid CO ₂ in the high-pressure vessel were stirred for 5 minutes with a stirrer to become a homogeneous phase, and then the stirrer was stopped and allowed to stand for 10 minutes. FIG. 12 shows the state of the absorbing liquid and liquid CO ₂ in the high-pressure vessel after standing still.
As is clear from FIG. 12, it was found that the absorption liquid and the liquid CO ₂ were separated again by allowing to stand after stirring. This is considered that the absorption liquid and the liquid CO ₂ are insoluble in each other and the specific gravity difference is large, so that they are promptly separated into two phases. The two-phase liquid level before stirring and the two-phase liquid level after stirring and standing were at the same level.

It is a section lineblock diagram of a gas refining method and its device of a 1st embodiment of the present invention. Ru sectional view der corresponding to FIG. 1 showing a second embodiment of the present invention. It is a section lineblock diagram corresponding to Drawing 1 showing a 4th embodiment of the present invention. It is a section lineblock diagram corresponding to Drawing 1 showing a 5th embodiment of the present invention. It is a cross-sectional block diagram corresponding to FIG. 1 which shows 6th Embodiment of this invention. It is a block diagram which shows the system of 7th Embodiment of this invention. It is a block diagram which shows the system of 8th Embodiment of this invention. It is a diagram showing the changes associated with pressure change in the solubility of CO ₂ gas into the absorbing fluid of Example 1 at a measurement temperature of 35 ° C.. It is a diagram showing an H ₂ S gas and changes associated with pressure change in the solubility of COS gas into the absorption liquid of Example 1 at a measurement temperature of 35 ° C.. H ₂ gas into the absorbing fluid of Example 1 at a measurement temperature of 35 ° C., illustrates a CH ₄ gas, change due to pressure change in the solubility of CO gas and N ₂ gas. Absorbing liquid is a photographic view showing the state of phase separation (polyethylene glycol) and the liquid CO _2.

Explanation of symbols

12 Compressor 13 Absorption Tower 17 Circulation Pump 41 Liquid Acid Gas, Liquid CO ₂
42 Absorbing liquid 46 Separator / Regenerator 47 Cooler 48 Centrifuge
7 1 Additive 72 Absorption liquid storage tank 75 Additive-containing absorption liquid 81 Additive storage tank 82 Pressure adjusting means 83 Distillation separator 84 Heating means 91 Water storage tank

Claims (16)

One or two or more polymers selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin at the top of the absorption tower (13) maintained at a predetermined temperature and a predetermined pressure, respectively. And an absorption liquid (42) consisting of one or more acid gases selected from the group consisting of CO ₂ , H ₂ S and COS, and H ₂ , CH _4, CO, that by supplying a mixed gas containing one or more non-acidic gases selected from the group consisting of O ₂ and N _2, contacting the mixed gas into the absorbing solution (42) By absorbing the acidic gas in the absorbing liquid (42), separating the non-acidic gas and the acidic gas and recovering the non-acidic gas from the absorption tower (13),
The acidic gas is liquefied by supplying the absorbing liquid that has absorbed the acidic gas to the separation regenerator (46) maintained at a predetermined pressure and maintained at a temperature lower than the temperature in the absorption tower (13). The liquid acid gas (41) is separated from the absorption liquid (42) by the mutual insolubility and specific gravity difference between the liquid acid gas (41) and the absorption liquid (42) and recovered from the separation regenerator (46). And regenerating the absorbing liquid (42),
Supplying the regenerated absorption liquid (42) to the upper part of the absorption tower (13).   The pressure in the absorption tower (13) is maintained at 4 to 25 MPa, the temperature is maintained at 0 to 100 ° C., and the pressure in the separation regenerator (46) is maintained at 4 to 25 MPa. The method for purifying a mixed gas containing an acidic gas according to claim 1, wherein the temperature is maintained at -30 to 30 ° C lower than the temperature in 13).   Before supplying to the separation regenerator (46), the absorption liquid containing acid gas discharged from the absorption tower (13) and cooled to a temperature lower than the temperature in the absorption tower (13) is centrifuged or stirred. The method for purifying a mixed gas containing an acidic gas according to claim 1, further comprising a step.   The mixed gas containing acidic gas according to claim 1, wherein one or more additives (71) selected from the group consisting of water, alcohols, ethers and phenols are added to the absorbent (42). Purification method.   One or more additives (71) selected from the group consisting of water, alcohols and ethers are supplied to the separation regenerator (46), and the pressure and temperature in the separation regenerator (46). By adjusting the specific gravity difference between the liquid acid gas (41) and the additive-containing absorbent (75) in the separation regenerator (46), and the separation regenerator (46) discharged from the separation regenerator (46). The additive-containing absorbing liquid (75) is supplied to the distillation separator (83), and the inside of the distillation separator (83) is heated to a predetermined temperature, whereby the additive-containing absorbing liquid (75) is added. The method for purifying a mixed gas containing an acidic gas according to claim 1, further comprising a step of distilling and separating the agent (71) from the absorbing liquid (42).   The method for purifying a mixed gas containing an acid gas according to claim 1, wherein the flocculant is added to the absorbent containing the liquid acid gas in the separation regenerator. The acidic gas according to claim 1, wherein the acidic gas is CO ₂ gas, and water is supplied into the absorbing liquid (42) containing liquid CO ₂ (41) in the separation regenerator (46) maintained at a pressure of 4 to 25 MPa. A method for purifying a mixed gas containing gas. CO _2, H ₂ and S and one or more acid gas selected from the group consisting of _{COS, H 2, CH 4,} CO, O 2 and one selected from the group consisting of N ₂ or 2 A compressor (12) for compressing a mixed gas containing a non-acidic gas of a species or more;
The above-mentioned compressed mixed gas is supplied to the lower part, and the upper part is an absorbing liquid comprising one or more polymers selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyether, polyester, polyalkane and polyolefin (42 ) Is supplied, and the mixed gas is brought into contact with the absorbing liquid (42) to absorb the acidic gas into the absorbing liquid (42) to separate and recover the non-acidic gas from the acidic gas ( 13) and
A cooler (47) for cooling the absorbing liquid (42) that has absorbed the acid gas;
The cooled absorption liquid (42) is supplied, and the liquid acid gas (41) is separated from the absorption liquid (42) by the mutual insolubility and specific gravity difference between the liquid acid gas (41) and the absorption liquid (42). Separating and regenerator (46) to recover and reuse the absorption liquid (42),
A purification apparatus for a mixed gas containing acidic gas, comprising: a circulation pump (17) for supplying the absorption liquid (42) discharged from the separation regenerator (46) to the upper part of the absorption tower (13) while maintaining a high pressure. .   The apparatus for purifying a mixed gas containing an acid gas according to claim 8, wherein the absorption tower (13), the cooler (47), and the separation regenerator (46) are integrally provided.   The apparatus for purifying a mixed gas containing acidic gas according to claim 8 or 9, wherein a centrifuge (48) or a stirrer is provided between the cooler (47) and the separation regenerator (46).   Absorption liquid (42) added with one or more additives (71) selected from the group consisting of water, alcohols, ethers and phenols is stored, and this additive-containing absorption liquid (75) is stored. The apparatus for purifying a mixed gas containing an acidic gas according to any one of claims 8 to 10, wherein an absorption liquid storage tank (72) for supplying the absorption tower (13) is provided.   An additive storage tank (81) in which one or more additives (71) selected from the group consisting of water, alcohols and ethers are stored and connected to the upper part of the separation regenerator (46); Pressure adjusting means (82) for adjusting the pressure in the separation regenerator (46) provided in the separation regenerator (46), and the separation regenerator (46) connected to the lower part of the separation regenerator (46) The distillation separator (83) for storing the additive-containing absorption liquid (75) separated in specific gravity and transferred to the lower phase thereof, and the inside of the distillation separator (83) provided in the distillation separator (83) The apparatus for purifying a mixed gas containing an acidic gas according to any one of claims 8 to 10, further comprising a heating means (84) for heating to a predetermined temperature.   The apparatus for purifying a mixed gas containing an acidic gas according to any one of claims 8 to 10, wherein a flocculant tank for storing the flocculant is connected to a separation regenerator. A water storage tank in which the acid gas is CO ₂ gas, and pressure adjusting means (82) for maintaining the pressure in the separation regenerator (46) at 4 to 25 MPa is provided in the separation regenerator (46), and water is stored therein. The apparatus for purifying a mixed gas containing acidic gas according to any one of claims 8 to 10, wherein (91) is connected to a lower portion of the separation regenerator (46). One or more fuels selected from the group consisting of desulfurized gasoline, naphtha, kerosene, methanol, dimethyl ether, liquefied petroleum gas and natural gas are reformed, CO converted and CO removed to mix H ₂ and CO ₂ After the gas is formed, the mixed gas is used using the gas purification method described in any one of claims 1 to 7 or using the gas purification device described in any one of claims 8 to 14. A system that separates and collects H ₂ and CO ₂ , supplies the separated and collected H ₂ to a hydrogen station, and adiabatically expands the separated and collected CO ₂ to produce dry ice. One or more fuels selected from the group consisting of desulfurized gasoline, naphtha, kerosene, methanol, dimethyl ether, liquefied petroleum gas, and natural gas are installed in an on-vehicle reforming vehicle that uses a fuel cell as a drive source. After reforming, CO conversion and CO removal on a vehicle to form a mixed gas of H ₂ and CO ₂ , this mixed gas is used by using the gas purification method described in any one of claims 1 to 7 or 15. The gas purifier according to claim 8 is used to separate and recover H ₂ and liquid CO _2, and the separated and recovered H ₂ is supplied to the fuel cell, and the liquid A system that temporarily stores CO ₂ in the vehicle and collects it later.