JP2003327981A - Gas purification apparatus and power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas purification apparatus and a power generation system having excellent stability of the water level control of an absorption solution absorbing an acidic gas, or the like. <P>SOLUTION: The gas purification apparatus is equipped with a first absorption column 7 in which the basic absorption solution 44 is made to flow down oppositely to a gas 1 to be treated and the acidic gas is absorbed in the absorption solution, a regeneration tank 40 which is arranged at a position to make the absorption solution flowing out from the first absorption column flow into the regeneration tank 40 by a water head difference 60, stores the absorption solution flowing into the regeneration tank, blows a regeneration gas 31 in the stored absorption solution and regenerates the absorption solution having absorbed the acidic gas, and a circulation route 23 for circulating the absorption solution 44 between the absorption column 7 and the regeneration tank 40. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas refining apparatus and a power generation system, and more particularly to a carbon dioxide contained in a gas to be treated such as a digestion gas by using an absorption apparatus and a regeneration apparatus and circulating a basic absorption liquid. The present invention relates to a gas purification device and a power generation system for removing acidic gas such as gas.

[0002]

2. Description of the Related Art In a conventional gas refining system, as shown in FIG. 9, a raw material gas 1 is introduced into an absorption tower 7, and the absorbing liquid is vaporized in a counterflow section 6 composed of the raw material gas 1 and a packing material. Contact and absorb carbon dioxide. The absorption liquid that has absorbed carbon dioxide gas is stored in the liquid reservoir 3 located at the bottom of the absorption tower 7, and the absorption liquid 4 stored in the liquid reservoir 3 is passed through the absorption liquid heat exchanger 11 and the outlet pipe 14 by the pump 10. And is liquid-fed to the upper part of the regeneration tower 22. The absorption liquid heat exchanger 11 uses the hot water 12 for the hot water pipe 15
The absorption liquid is heated by passing it through. The regeneration gas 31 is passed through the gas blower 32 to the regeneration tower 22.
Then, the absorption liquid is brought into gas-liquid contact with the regeneration gas 31 in the counter flow portion 19 formed of the filler to release carbon dioxide gas. The absorption liquid accumulated in the liquid reservoir 21 is pumped by the liquid pipe 23,
The liquid is sent to the upper part of the absorption tower 7 via 25, 27 and the heat exchanger 26, circulated and reused. The heat exchanger 26 uses the cooling water 28 for cooling water piping 29,
It is configured to cool the absorbing liquid by passing it through 30.

Such a gas refining system regenerates the absorption liquid, which is an endothermic reaction, and the higher the absorption liquid temperature in terms of chemical equilibrium, the higher the regeneration efficiency. The temperature of the absorbing liquid is raised by supplying it to the absorbing liquid heat exchanger 11. For example, the absorption liquid heat exchanger 1
The temperature of the absorbing liquid in the outlet pipe 14 of 1 is usually 70 ° C to 120 ° C.
Adjusted to ℃.

On the other hand, the refining process of the raw material gas 1 is an exothermic reaction, and the lower the absorbing liquid temperature, the higher the absorption efficiency.
The absorption liquid to be sent to the absorption tower 7 is cooled by the cooling water 28 supplied to the heat exchanger 26. For example, the temperature of the absorbing liquid in the outlet pipe 27 of the heat exchanger 26 is usually adjusted to 30 ° C to 40 ° C.

[0005]

The gas purification system is
As described above, two pumps are required to circulate the absorption liquid between the absorption tower and the regeneration tower, and complicated control is required to control the water level of the absorption liquid stored in both the absorption tower and the regeneration tower. Was there.

Therefore, it is an object of the present invention to provide a simple and highly efficient gas purifying apparatus and power generation system by reducing the number of pumping apparatuses for circulating the absorbing liquid.

[0007]

In order to achieve the above object, the gas purifying apparatus according to the first aspect of the present invention is implemented, for example, by using the gas purifying system shown in FIG. In a gas purification apparatus for purifying a gas to be treated by removing an acidic gas in a gas to be treated, a basic absorbing liquid S1 is flowed down, and the gas to be treated M1 is opposed to the flowing absorbing liquid S1. By flowing, the first absorption tower 7 in which the acidic gas is absorbed in the absorbent S1 and the absorbent 4 which has absorbed the acidic gas flows out; and the absorbent 4 flowing out from the first absorption tower 7 is Of the regeneration tank 40, which is arranged at a position where the first absorption tower 7
The absorption liquid 44 flowing in from the pool is accumulated, and the regeneration gas 62 is blown into the accumulated absorption liquid 44 to regenerate the absorption liquid 44 that has absorbed the acidic gas; and the absorption tower 7 and the regeneration tank 40. A circulation path for circulating the absorbing liquid 44 between the liquid pipe 23 and the liquid (for example, the liquid pipe 23, the pump 24, the liquid pipe 2
5, liquid pipe 27, and liquid pipe 42).

Here, the gas to be treated 1 can be an anaerobic digestion gas, the basic absorbing liquid 44 can be an alkanolamine such as diethanolamine as an organic alkaline liquid, and the acidic gas is For example, carbon dioxide gas or hydrogen sulfide is included, and the regenerated gas 31 can be atmospheric air. The regeneration tank 40 may be filled with a filler (see FIG. 5).

According to this structure, the absorption liquid 4 which has absorbed the acidic gas flowing out from the first absorption tower 7 is transferred to the head difference 60.
Since it can be naturally flown into the regeneration tank 40,
A pumping device can be dispensed with.

In order to achieve the above object, the gas purifying apparatus according to the invention as claimed in claim 2 is implemented by using, for example, the gas purifying system shown in FIG. 2, and the circulation paths 23, 24, 25, At 27, the basic absorption liquid 44 regenerated in the regeneration tank 40 is supplied from the regeneration tank 40 to the first absorption tower 7 as it is.

Here, the basic absorption liquid 44 as it is means a mode in which the basic absorption liquid 44 is directly sent to the absorption tower 7 without abruptly changing the liquid temperature of the basic absorption liquid 44, for example, the basic absorption liquid. Without absorbing the liquid 44 actively, typically, when the absorbing liquid temperature is higher than the ambient temperature, the absorbing liquid 44 liquid-fed in the circulation path naturally radiates heat in the liquid pipe. Say. Therefore, it includes a configuration in which the absorption liquid 44 is liquid-fed from the regeneration tank 40 to the absorption tower 7 without installing a cooling device such as a water-cooled heat exchanger between the regeneration tank 40 and the absorption tower 7.

With this configuration, the circulation paths 23, 2
It is not necessary to provide an additional cooling source for cooling the basic absorption liquid 44 at 4, 25 and 27.

In order to achieve the above object, the gas purifying apparatus according to any one of claims 1 and 2 according to the invention of claim 3 is a gas purifying system shown in, for example, FIG. 3 or 4. Secondly, the basic absorption liquid S2 is made to flow down, the gas M2 to be treated is made to flow opposite to the flowing absorption liquid S2, and the absorption liquid S2 is made to absorb the acidic gas. The first absorption tower 7a and the second absorption tower 7b are arranged in parallel to the flow of the absorption liquids S1 and S2.

Here, the first absorption tower 7a and the second absorption tower 7b are arranged in parallel to the flow of the absorbing liquids S1 and S2, which means that the absorption capacity of carbon dioxide gas is typically the same. The liquids S1 and S2 are arranged so as to be branched and supplied to the first absorption tower 7a and the second absorption tower 7b, respectively.

With this configuration, the first absorption tower 7a
The carbon dioxide gas in the gases M1 and M2 to be processed which pass through the second absorption tower 7b can be effectively absorbed.

In order to achieve the above object, a gas purifying apparatus according to a fourth aspect of the present invention is implemented by using a gas purifying system shown in FIG. 7, for example, in a gas to be treated containing an acidic gas. In a gas purifying apparatus for purifying the gas to be treated by removing the acidic gas of
An absorption tank 70 in which the acidic gas is absorbed in the absorbing liquid 80 and the absorbing liquid 80 that has absorbed the acidic gas flows out; The absorption liquid 80 flowing out from the inflows, the absorbed absorption liquid 44 is accumulated, and the regeneration gas 31 is blown into the accumulated absorption liquid 44, whereby the absorption liquid 44 that has absorbed the acidic gas is regenerated. Tank 40
And a circulation path for circulating the absorption liquid 44 between the absorption tank 70 and the regeneration tank 40 (for example, the liquid pipe 23, the pump 24, the liquid pipe 25, and the liquid pipe 42);
0 or regeneration tank 40 from one to the other head difference 60
Has a head difference flow path 46 for allowing the absorbing liquid 44 to flow in,
The pump 24 is provided for sending the absorbing liquid from the tank on the downstream side of the head difference channel 46 to the tank on the upstream side.

Further, in the gas purifying apparatus according to claim 4,
For example, the circulation path 42 has its one end portion 43 at the absorption tank 70.
Side and place it in the absorbent 80, and the other end is in the regeneration tank 4
It is inserted into the 0 side and arranged in the absorbing liquid 44 to form the head difference channel 46. The absorption liquid 80 in the absorption tank 70 and the regeneration tank 40
Due to the head difference 60 with respect to the absorption liquid 44 inside, the absorption liquid 80 in the absorption tank 70 moves from one end to the other end of the circulation path.
It may be configured to flow into the regeneration tank 40 side through 6.

With this structure, when either the absorption tank 70 or the regeneration tank 40 is set as the tank on the downstream side of the head difference flow path 46, the absorption liquid is transferred from the tank on the downstream side to the layer on the upstream side. Four
Since the pump 24 for sending 4 is provided, the absorption liquid 80 is circulated from the upstream tank through the head difference flow path 46 to the downstream tank.

In order to achieve the above object, a power generation system according to a fifth aspect of the present invention is implemented by using, for example, the power generation system shown in FIG. 8, and any one of the first to fourth aspects. The gas purification device 82 according to item 1.
And a fuel cell system 92 that uses the gas refined by the gas purifier as a fuel to generate electricity by an electrochemical reaction between the fuel and the oxidant.

According to this structure, the gas from which the acidic gas has been removed from the gas purification system according to any one of claims 1 to 4 can be supplied to the fuel cell system and purified by the gas purification system. Since the fuel cell system 92 that uses the gas as a fuel to generate electricity by the electrochemical reaction of the fuel and the oxidant is provided, it is possible to generate electricity using the gas. Further, if the heat exchanger 54 that heats the absorbing liquid with the exhaust heat generated in the fuel cell system 92 is provided, the exhaust heat can be recovered and effectively used. The fuel cell system 92 saves the time and effort of decarbonating the gas purified by the gas purifier 82, and enables highly efficient fuel cell power generation.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same or corresponding members are designated by the same reference numerals or similar reference numerals, and redundant description will be omitted.

A digestive gas purification system as a gas purification apparatus according to the first embodiment of the present invention will be described with reference to the system diagram of FIG.

The digestion gas purification device receives a digestion gas containing carbon dioxide as an acidic gas from a digestion gas source. The digestive gas is a gas containing methane gas or the like as a main component, which is obtained by fermentation of biomass or organic waste. Biomass refers to algae, rice meal, sugar cane meal, alcohol-fermented meal, etc., and organic waste refers to waste liquid from food production, surplus sludge generated from livestock wastewater, sewage treatment, and the like.

Digestion gas obtained by methane fermentation of organic matter generally varies from 60 to 70% of methane, 30 to 40% of carbon dioxide and 0 to 2% of hydrogen as main components, although it depends on the type of organic matter and methane fermentation conditions. , Nitrogen is 0-2%
In addition, hydrogen sulfide and hydrogen chloride are contained as trace components in the range of several tens to several hundreds ppm. on the other hand,
For example, the purified gas supplied to the hydrogen production process is required to have a low concentration of acidic gas such as hydrogen sulfide and carbon dioxide. Alternatively, particularly, carbon dioxide gas is required to have a predetermined concentration.

The digestive gas purification apparatus comprises an absorption tower 7 as an absorber connected to the source of digestive gas and a raw material gas pipe in which a gas blower 2 is inserted and arranged. The absorption tower 7 is a tower configured as a cylindrical container, and is installed on the ground with the central axis of the cylinder in the vertical direction. A gas-liquid contact layer 6 is provided in the central portion in the vertical direction of the cylindrical container, and a spray nozzle 5 for spraying the absorbent S1 onto the gas-liquid contact layer 6 is installed in the space above the container. S1 contacts the source gas M1 rising from the lower part of the gas-liquid contact layer 6.

The absorption device is not limited to the absorption tower 7 having the spray nozzle 5 and the gas-liquid contact layer 6 as shown in the drawing, but is provided at the tank 3 for storing the basic absorption liquid 4 and at the bottom of the tank 3. Alternatively, a gas injection nozzle (not shown) may be provided. In this case, by blowing gas into the liquid from the nozzle, while the gas rises like a bubble in the liquid 4,
The acid gas is absorbed by the liquid 4.

The bottom of the cylindrical container of the absorption tower 7 serves as a tank 3 as a liquid reservoir. Outside the absorption tower 7,
A liquid level detector (not shown) that detects the liquid level of the liquid reservoir, a liquid level controller that controls the liquid level to a predetermined liquid level set value based on the detected liquid level, and control from the liquid level controller An inverter that receives the signal and adjusts the rotation speed of the pump 24 described below may be installed.

The digestion gas purifying apparatus is provided with a regeneration tank 40 installed at a low position adjacent to the absorption tower 7. Regeneration tank 40
Is a tank configured as a cylindrical container, and is installed on the ground with the central axis of the cylinder in the vertical direction. The absorbing liquid 44 is stored in the cylindrical tank, and the space above it is regenerated. It has a space 48 for containing the gas 31 and carbon dioxide gas. Further, a gas injector for injecting the regeneration gas 31 is installed from the lower portion of the cylindrical tank of the regeneration tank 40, and the bubble-shaped regeneration gas 62 is ejected.

Further, the regeneration tank 40 is not limited to the cylindrical tank as shown in the drawing, but a rectangular parallelepiped tank for storing the basic absorption liquid 44 and the heat exchange tube 5 arranged in the tank.
4 may be provided. Hot water 52 and steam are supplied to the heat exchange tube 54. The absorbing liquid 44 stored in the tank by the heat exchange tube 54 is heated to release gas.

Further, the flow rates of the warm water 52 and steam supplied to the heat exchange tube 54 are controlled by the valve 55 connected to the controller 53. For this flow rate, a liquid temperature signal is received from the absorbing liquid temperature sensor installed near the heat exchange tube 54 in the regeneration tank 40 to the controller 53, and for example, the liquid temperature is set to a first setting of about 40 ° C to 55 ° C. The temperature is set arbitrarily within the temperature range and controlled by increasing or decreasing the flow rate of the hot water 52 or the like.

Here, regarding the absorbing liquid, the liquid S1 flowing down in the absorption tower 7 is referred to as the absorbing liquid before absorbing the acidic gas, and the tank 3 for storing the liquid is
For the sake of convenience, the liquid stored in (1) is referred to as an absorption liquid that has absorbed acidic gas. The liquid that is stored in the regeneration tank 40 is a mixed absorption liquid of an absorption liquid that has absorbed the acidic gas and an absorption liquid that has recovered the carbon dioxide gas absorption rate. When it is not necessary to distinguish them, they are collectively referred to as an absorbent.

In the figure, the absorbing liquid 4 shows the liquid accumulated in the tank 3 of the liquid reservoir. The absorption liquid S1 in the upper part of the gas-liquid contact layer 6 which has not yet absorbed the acid gas has a higher absorption capacity for the acid gas than the absorption liquid in the tank 3 and has the same concentration as the absorption liquid accumulated in the regeneration tank 40. The temperature is low.

Therefore, even when the liquid S1 flowing in the absorption tower 7 needs to be distinguished, the liquid before absorbing the acidic gas is the absorbing liquid before absorbing the acidic gas and the liquid after absorbing the acidic gas is acidic. It is called absorption liquid that has absorbed gas. According to this name, the liquid sprayed by the spray nozzle 5 is the absorbing liquid before absorbing the acidic gas, and the liquid in the tank 3 of the liquid reservoir is the absorbing liquid absorbing the acidic gas.

The same applies to the regenerating tank 40. In the figure, the absorbing liquid 44 indicates the liquid accumulated in the regenerating tank 40.
The liquid supplied from is the absorption liquid that has absorbed the acidic gas before being regenerated, and the liquid in the regeneration tank 40 is the absorption liquid that is being absorbed during the regeneration treatment or after the regeneration treatment.

The liquid reservoir tank 3 of the absorption tower 7 and the head difference flow passage 46 of the regeneration tank 40 are connected by a liquid pipe 42. In the liquid pipe 42, the water head difference 6 between the liquid level of the absorbent 4 accumulated in the tank 3 on the absorption tower 7 side and the liquid level of the absorbent in the regeneration tank 40
With 0, the absorbing liquid 4 flows down naturally. Therefore, the liquid pipe 4
The system of No. 2 does not require a liquid feeding mechanism by a pump.

Regeneration tank 40 and spray nozzle 5 of absorption tower 7
Are connected to each other through a circulation path constituted by a pump 24 and a liquid pipe 27 which are inserted and arranged between the liquid pipe 23 and the liquid pipe 25. The pump 24 is driven by an electric motor (not shown). The electric motor is driven by a frequency-regulated power source supplied from an inverter. The inverter adjusts the frequency based on the signal from the controller. By adjusting the frequency,
Adjusting the rotation speed of the pump 24, the liquid pipe 23 and the liquid pipe 2
5 and the flow rate (circulation amount) of the absorbing liquid flowing through the liquid pipe 27 are adjusted.

Liquid pipe 2 between pump 24 and liquid pipe 27
A radiator 58 as a heat exchanger is additionally disposed at 5. The radiator 58 can use an air cooling method or a water cooling method, but it is preferable to use a natural air cooling method or a forced air cooling method using a fan in order to downsize the facility. The radiator 58 gradually cools the absorbing liquid in the liquid pipe 25 with a predetermined temperature gradient.

Further, an absorbing liquid temperature detector (not shown) as a temperature detector is installed in the liquid pipe 27 connected to the pump 24 system and located downstream of the radiator 58, and the controller 53 described above absorbs the liquid in the liquid pipe. Outputs the liquid temperature signal, and the temperature that most reflects the acid gas absorption capacity of the absorbing liquid, for example,
The absorption liquid in the liquid pipe 27 can be configured to be set at a liquid temperature of 40 ° C. to 50 ° C. In this case, the flow rate of the hot water 52 or the like supplied to the heat exchange tube 54 is controlled on the basis of the detected liquid temperature of the cooled absorption liquid to control the absorption liquid temperature in the regeneration tank 40 to a liquid temperature higher than 50 ° C. Good.

A liquid flow rate detector (not shown) is inserted in the liquid pipe 27 to detect the circulating amount of the absorbing liquid between the absorption tower 7 and the regeneration tank 40 to control the pump 24 on the output side of the regeneration tank 40. You may.

A refined gas pipe 8 is connected to a portion of the absorption tower 7 above the gas-liquid contact layer 6, and the gas-liquid contact layer 6 is connected to the purified gas pipe 8.
It is configured to deliver the purified gas from the upper space. The methane-enriched gas 9 as a purified gas is delivered from the absorption tower 7 by the blowing pressure by the gas blower 2 inserted and arranged in the gas pipe between the digestion gas source and the absorption tower 7.

Further, an acid gas concentration detector (not shown) may be installed in the gas pipe 8 at the top of the absorption tower 7 to detect the methane enrichment. However, the installation position of the acid gas concentration detector is
Not only here, but at a position suitable for concentration detection, the absorption tower 7
It may be the space above the gas-liquid contact layer 6. However, if it is provided in the pipe, there is an advantage that the uniformed concentration can be detected unlike the staying portion.

The gas-liquid contact layer 6 of the absorption tower 7 may be loaded with a filler, and any kind of filler may be used as long as it has sufficient corrosion resistance and heat resistance and high contact efficiency. . As the structure, any structure may be used as long as it makes it easy to make countercurrent contact with the rising source gas M1 while allowing the absorbing liquid S1 to flow down, and for example, a metal or synthetic resin fiber can be used as the filler filling structure.

The filler 68 may be loaded in the intermediate position between the upper and lower sides of the regenerator 40, and a modification is shown in FIG. Any type of material for the filler 68 may be used as long as it has sufficient corrosion resistance and heat resistance, and high contact efficiency.

The structure is a fiber structure that restricts the floating of fine bubbles ejected from the regeneration gas injector, provides a passage for increasing the gas-liquid contact time between the fine bubbles and the absorbing liquid 44, and provides a plurality of fine bubbles. Any filler structure may be used as long as it is a structure in which bubbles combine to increase the particle size and divide the bubbles to maintain the fine bubbles of the regeneration gas 31 floating in the absorbing liquid 44.
Fibers made of metal or synthetic resin can be used as the filler filling structure. The levitation passage is narrowed by the fibers of the filling material, and the arrival time until the regeneration gas 31 reaches the liquid surface of the absorbing liquid 44 is extended.

A fine bubble-like regeneration gas 62 is blown from a regeneration gas injection pipe arranged in the regeneration tank 40, and the blown regeneration gas 62 rises in the absorbing liquid 44 in the form of fine bubbles and passes through the filler 68. Then, it is discharged into the absorbent above the filler. The gas further stays in the upper space 48 of the regeneration tank 40 from the absorption liquid surface, and then is discharged from the top outlet pipe 17.

Further, the fine bubbles of the plurality of regeneration gases 62 discharged from the regeneration gas injection pipe are bonded to each other while the absorbing fluid is floating, and the particle size is gradually increased. The liquid contact decreases, but the filler 6 shown in FIG.
Since the bubbles are divided by 8 to prevent the particle size from increasing and the fine bubbles are maintained until reaching the liquid surface of the absorbing liquid 44, a good gas-liquid contact state can be formed. The filler 68 is formed into a cylindrical shape by weaving metal or synthetic resin fibers at a density such that bubbles of regenerated gas pass through,
It is loaded so as to be in close contact with the inner wall of the container of the regeneration tank.

Further, the partition wall 50 installed vertically at the bottom of the regeneration tank 40 separates the bubbles of the regenerating gas 62 discharged from the partition wall regenerating gas injection pipe from the absorbing liquid 44 and circulates the circulation path 23.
Prevent air bubbles from getting inside. Further, the head difference channel 46 is also installed so that the tip portion thereof is oriented in the direction of the absorbing liquid surface so that the bubbles of the regeneration gas are not mixed.

The digestion gas purification device can further include a control device (not shown) for controlling the flow rate of the liquid supplied from the regeneration tank 40 to the absorption tower 7, and the control device controls the pump 24 to circulate the circulation path 23. Controls the flow rate of the absorbing liquid flowing through. The control device receives a concentration signal from the acid gas concentration detector, a flow signal from the liquid flow detector, a temperature signal from the liquid temperature detector, and a temperature signal from the liquid temperature detector,
The liquid flow rate is controlled by sending a control signal to the inverter.

The digestive gas purifying apparatus according to the second embodiment will be described with reference to the system diagram of FIG. The present embodiment is a digestive gas purifying apparatus that does not include a radiator 58 that cools the absorbing liquid provided in a liquid pipe 25 that connects the regeneration tank 40 and the absorption tower 7 of FIG.

The temperature of the absorbing solution is controlled by the temperature controller 53 as in the digestion gas purifying apparatus shown in FIG. The temperature controller 53 inserts an absorption liquid temperature detector into the regeneration tank 40 to detect the liquid temperature, and controls the inflow amount of the hot water 52 with the valve 55 based on the detected liquid temperature information.

In the present embodiment, the treatment liquid temperature detector connected to the controller 53 detects the temperature of the absorbing liquid 44, and the temperature is arbitrarily set within the second setting temperature range of 40 ° C. to 55 ° C. Then, the liquid temperature of the absorbing liquid 44 is controlled.

The treatment liquid sent from the regeneration tank 40 to the absorption tower 7 is naturally cooled in the circulation path due to the difference from the atmospheric temperature, but the absorption liquid at about 40 ° C. or higher is supplied to the absorption tower 7. Therefore, the temperature of the absorbing liquid in both the absorption tower 7 and the regeneration tank 40 is controlled to be in a substantially equal temperature range, and the absorbing action and the regenerating action can be performed. The absorption tower 7, the regeneration tank 40, and
The circulation path 23 is similar to that of the first embodiment described above, and the description thereof is omitted.

In the digestion gas purifying apparatus applied to a small-scale fuel cell system, the amount of heat exhausted from the fuel cell is small and the amount of heat for regeneration of the absorbent can be reduced. The present inventor has conducted a test study on the absorption capacity and the regeneration capacity of the absorption liquid, and as a result, the absorption tower 7 and the regeneration tank 40 are well-balanced by setting the absorption liquid temperature in the range of 40 ° C. to 55 ° C. It was found that it has an absorption function and a regeneration function.

Here, the temperature of the absorption liquid is, for example, the regeneration tank 40.
On the side, the absorption liquid temperature is set to about 55 ° C. higher than the atmospheric temperature, and the absorption tower is naturally cooled while flowing through the circulation path constituted by the liquid pipe 23, the pump 24, the liquid pipe 25, and the liquid pipe 27. The temperature of the absorbent sprayed from the spray nozzle 5 of No. 7 is about 45 ° C.

When the absorption liquid is 40 ° C. or lower, the carbon dioxide absorption capacity is high due to the temperature dependence of the gas-liquid equilibrium, but at a liquid temperature of 40 ° C. or lower, the regeneration efficiency is lowered and the carbon dioxide gas content The liquid is sent to the absorption tower 7 while the pressure is still high, and the good absorption effect of carbon dioxide gas or the like as the absorption liquid before absorbing the acidic gas decreases.

On the other hand, when the temperature of the absorbing solution is increased, the regeneration capacity is improved, but when the absorbing capacity of carbon dioxide gas decreases and the liquid temperature exceeds 55 ° C., the carbon dioxide gas as the absorbing solution before absorbing the acidic gas is increased. Absorption reaction is reduced. Further, an increase in the regeneration temperature leads to an increase in the amount of heat required for the system, which is not preferable. Therefore, it is possible to provide a system in which the temperature of the absorbent used for circulation is controlled in the range of 40 ° C. to 55 ° C. so that the absorption of carbon dioxide gas and the like of the absorbent and the regeneration of the absorbent are compatible.

As described above, the regeneration reaction for releasing carbon dioxide gas or the like from the absorbing liquid 44 is preferably at high temperature, while the absorption reaction for absorbing carbon dioxide gas or the like from the raw material gas 1 is preferably at low temperature. Therefore, in the present embodiment, in the case of constructing a system which does not have a radiator and sends the regenerated absorption liquid from the regeneration tank 40 to the absorption tower 7, the absorption liquid temperature which satisfies both the absorption reaction and the regeneration reaction is set. Decided to choose.

In the present embodiment, for example, a simpler gas purification system is provided by selecting the absorption liquid temperature within the allowable range of the carbon dioxide concentration in the methane concentrated gas 9 supplied to the fuel cell power generation system. That is, the temperature of the absorbing liquid 44 in the regeneration tank 40 during or after the regeneration treatment is set to about 40 ° C. by the heat exchange tube 54 installed in the regeneration tank 40.
The temperature is set to a range of from 55 ° C. to 55 ° C., and a gas-liquid contact is made with the bubble-shaped regenerating gas 62 to release carbon dioxide gas or the like to perform a regenerating process.

Absorption liquid 4 during or after this regeneration treatment
4 is sprayed from the spray nozzle 5 in the absorption tower 7 through the liquid pipe 23 in the circulation path, and the raw material gas M1 rising in the tower.
Is brought into contact with gas and liquid to absorb carbon dioxide gas and the like to generate a methane concentrated gas 9. The absorption liquid S1 set in the range of about 40 ° C. to 55 ° C. can remove carbon dioxide gas and the like from the raw material gas 1 to the extent that the concentration of methane as the fuel of the fuel cell is satisfied.

In addition, since the regeneration reaction in the regeneration tank 40 does not proceed sufficiently with the absorbing solution whose absorbing solution temperature is lower than 40 ° C., the partial pressure of carbon dioxide gas in the absorbing solution 44 during the regeneration process is high, and the absorbing tower 7 remains as it is. When the absorption liquid 44 is circulated, a good absorption reaction of carbon dioxide gas or the like as the absorption liquid before absorbing the acidic gas cannot be expected, and the carbon dioxide absorption performance of the absorption tower 7 deteriorates.

Further, since the absorption reaction in the absorption tower 7 does not proceed sufficiently with the absorption liquid whose absorption liquid temperature exceeds 55 ° C.,
The carbon dioxide gas absorption performance is remarkably lowered, and it becomes difficult to satisfy the methane concentration as a fuel required by the fuel cell.
Further, since raising the regeneration temperature of the regeneration tank 40 causes an increase in the required heat amount of the entire system, the absorption liquid having the absorption liquid temperature set in the range of about 40 ° C. to 55 ° C. described above is also taken into consideration in terms of energy efficiency. It is desirable to recycle.

A digestive gas purification system as a gas purification apparatus according to a third embodiment of the present invention will be described with reference to the system diagram of FIG. The description of the members common to the above-described embodiment will be omitted.

The gas purification system comprises an absorption tower 7a as a first absorption device for introducing the raw material gas 1 from the raw material gas pipe in which the gas blower 2 is inserted and arranged. Absorption tower 7
a is a tower configured as a cylindrical container, and is installed on the ground with the central axis of the cylinder being the vertical direction. A gas-liquid contact layer 6a is provided in the central part in the vertical direction of the cylindrical container,
A spray nozzle 5a for spraying the absorbing liquid S1 as the absorbing liquid onto the gas-liquid contact layer 6a is installed in the space above it.

Further, the gas purification system comprises a first absorption tower 7a and a second absorption tower 7b connected through a primary purified gas pipe 66. The second absorption tower 7b is a tower configured as a cylindrical container for introducing a purified gas obtained by primarily purifying the raw material gas M1 from above the first absorption tower 7a, and the central axis of the cylinder is vertically arranged on the ground. It is installed in the direction. A gas-liquid contact layer 6b is formed in the central portion in the vertical direction of the cylindrical container.
Is provided, and a spray nozzle 5b for spraying the absorbing liquid S2 on the upper part of the gas-liquid contact layer 6b is installed in the space above it.

The bottom of the cylindrical container of the first absorption tower 7a is
It is a liquid reservoir 3a. The liquid reservoir 3a and the head difference flow path 46 of the regeneration tank 40 are connected by a pipe 42a and a pipe 65. A valve 64a inserted into the pipe 42a controls the natural flow of the absorbing liquid 4a. Also, the second
The bottom of the cylindrical container of the absorption tower 7b is also a liquid reservoir 3b. The liquid reservoir 3b and the head difference channel 46 of the regeneration tank 40 are connected by a pipe 42b and a pipe 65. This piping 42
A natural flow of the absorbing liquid 4b is controlled by a valve 64b inserted in the valve b. Since the degree of gas volume reduction on the side of the second absorption tower 7b is higher, only the valve 64b on the side of the second absorption tower 7b is installed and the valve 64a on the side of the first absorption tower 7a is removed. You can also

Further, the lower part of the regeneration tank 40 and the spray nozzle 5a of the first absorption tower 7a are provided with a liquid pipe 23 as a circulation path, a pump 24, a liquid pipe 25, and a liquid pipe 27a.
Are connected through. The spray nozzle 5b of the second absorption tower 7b is connected through the liquid pipe 23, the pump 24, the liquid pipe 25, and the liquid pipe 27b. In addition,
A radiator may be arranged in the liquid pipe 25 arranged downstream of the pump 24, and the radiator may not be installed by adjusting the absorption liquid temperature after the regeneration treatment.

The operation of the present embodiment will be described with reference to FIG. In the gas purification system, a double tower type absorption device is used by the first and second absorption towers. The first absorption tower 7a and the second absorption tower 7b are installed in parallel in the vertical direction. That is, both absorption towers have the same installation bottom height and have the same tower length, and the raw material gases M1 and M2 flowing in the cylindrical containers of both and the absorbent S
The traveling distances of 1 and S2 are set to be equal.

Absorption liquid 44 regenerated by the regeneration tank 40
Is supplied to the spray nozzles 5a and 5b of the first absorption tower 7a and the second absorption tower 7b by the pump 24, respectively. The raw material gas 1 is introduced from the lower part of the first absorption tower 7a as described above and rises in the first absorption tower 7a.
As a primary purified gas that is introduced into the lower part of the second absorption tower 7b through the primary purified gas pipe 66 from the upper position of the first absorption tower and then rises in the second absorption tower 7b after absorbing carbon dioxide gas, etc. As for the raw material gas M2, the carbon dioxide gas is absorbed again by the absorbing liquid S2 before absorbing the acidic gas which is sprayed from the spray nozzle 5b, and the purified gas pipe 8 connected above the second absorption tower 7b concentrates methane as the purified gas. The gas 9 is delivered.

When the first absorption tower and the second absorption tower are arranged in parallel, the absorption liquids S1 and S2 before absorption of acidic gas having the same carbon dioxide absorption capacity from the regeneration tank 40 to both spray nozzles. It is possible to provide a recuperator-type absorption device capable of supplying carbon dioxide gas and the like with a high absorption rate. On the other hand, in the case of an absorption device in which two absorption towers are connected in series vertically, the distance or time during which the source gas 1 comes into gas-liquid contact with the absorption liquid is the same as in the parallel arrangement method, but in the upper absorption tower As a result of reusing the used absorption liquid in the lower absorption tower, the carbon dioxide partial pressure of the absorption liquid supplied to the lower storage has already risen, and the carbon dioxide absorption efficiency of the lower absorption tower is reduced.
Therefore, the parallel arrangement method of the absorption towers can provide a gas purification apparatus having a higher carbon dioxide gas absorption efficiency.

Further, in the illustrated absorption device, two absorption towers are arranged in parallel with the absorption liquids S1 and S2, and the gases M1 and M
The two streams are arranged in series. Gas M1, M2
It is possible to increase the absorption efficiency of carbon dioxide (concentration of methane gas after absorption) by increasing the number of absorption towers arranged in series with respect to the flow of gas, but the correlation between the number of additional absorption towers and the concentration of methane gas As a result of the test study,
It has been confirmed that the parallel arrangement method up to the tower can contribute to the carbon dioxide absorption rate.

The valve 64a for the first absorption tower is used for adjusting the liquid level of the absorption liquid 4a of the first absorption tower 7a, and
The absorption tower valve 64b is used for adjusting the liquid level of the absorption liquid 4b of the second absorption tower 7b. Since the carbon dioxide gas or the like is absorbed from the raw material gas M1 into the absorbing liquid S1 in the first absorption tower 7a, the gas volume gradually decreases.

Since the gas volume is decreased as described above, the pressure loss of the gas passing through the first absorption tower 7a and the second absorption tower 7b is different, and the liquid reservoirs 4a and 4b are connected to the regeneration tank 4 respectively.
In addition to the different absorption liquid velocities that naturally flow down to 0, for example, the gas volume in the second absorption tower into which the primary purified gas whose gas volume has been reduced by the first absorption tower 7a has been introduced further decreases, In some cases, the absorption liquid level in the liquid reservoir 3b at the bottom of the absorption tower rises and reaches the gas-liquid contact layer 6b. In particular, since the gas volume of the second absorption tower 7b arranged in the next stage is remarkably reduced, it is advisable to adjust the liquid level of the absorbing liquid or the natural flow rate by the valve 64b.

A digestion gas purification system as a gas purification apparatus according to a fourth embodiment of the present invention will be described with reference to the system diagram of FIG. The description of the members common to the above-described embodiment will be omitted.

In the gas purification system, the first absorption tower 7a and the second absorption tower 7b have a head difference 60a, 60b corresponding to the internal pressure of each absorption tower in the absorbing liquid flowing toward the regeneration tank 40.
It is arranged so that In the third embodiment, in the double tower parallel arrangement system, each absorption tower is connected to the regeneration tank 4
Although the amount of the absorbing liquid flowing down to 0 was adjusted by the valve, in the present embodiment, the first absorbing tower 7a is adjusted so as to adjust the natural flowing speed of the absorbing liquid caused by the internal pressure difference of the absorbing tower pipe.
And the height at which the second absorption tower 7b is arranged is changed.

For example, the internal pressure of the second absorption tower 7b is
Since the internal pressure of the first absorption tower 7a is lower than that of the first absorption tower 7a, the absorption liquid velocity flowing down from the liquid reservoir 3b of the second absorption tower to the regeneration tank flows down from the liquid reservoir 3a of the first absorption tower to the regeneration tank. It is lower than the absorption liquid velocity. The illustrated second absorption tower 7b is set so that the installation bottom height of the tower is higher than that of the first absorption tower 7a.

Due to the difference in the installation height of this tower, the head difference 60b between the second absorption tower 7b and the regeneration tank 40 is larger than the water head difference 60a between the first absorption tower 7a and the regeneration tank 40. To be configured. It is possible to balance the internal pressure difference between both towers by changing the head difference between both towers. By changing the installation height of the absorption tower to balance the internal pressure of the tower and the head difference,
The velocities of the absorbing liquid flowing down from the first and second absorption towers to the regeneration tank 40 can be controlled to be equal.

Similarly, even if the number of stages of the absorption towers arranged in array is increased, the head difference of the second absorption tower is made higher than that of the first absorption tower, and the second absorption tower is increased. More preferably, the head difference of the third-stage absorption tower is made higher, and the water head difference of the fourth-stage absorption tower is made higher than that of the third-stage absorption tower.

A digestive gas purification system as a gas purification apparatus according to a fifth embodiment of the present invention will be described with reference to the system diagram of FIG. Note that members common to the above-described embodiments can be used, and description of common members is omitted.

In the digestion gas purification system, the absorption tank 70 is constructed separately from the absorption tower 7, the regeneration tank 40 arranged downstream of the absorption tank 7, and the absorption liquid 44 is fed from the regeneration tank 40. A circulation path for inserting and arranging a pump 24 between the liquid pipe 23 and the liquid pipe 25, a source gas pipe for inserting and arranging the gas blower 2, and the source gas pipe for connecting the absorption tower 7 and the absorption tank 70. A gas pipe 74 and a liquid pipe 42 connecting the absorption tank 70 and the regeneration tank 40 are provided.
It is arranged at a higher position and the regeneration tank 40 is provided through the circulation path.
And the absorption tower 7 are connected to each other, and the absorption tank 70 is arranged below the absorption tower 7.

The absorption tower 7 is a tower constructed as a cylindrical container, and is installed on the ground with the central axis of the cylinder in the vertical direction. A gas-liquid contact layer 6 is provided at the center of the cylindrical container in the vertical direction, and a spray nozzle 5 for spraying the absorbing liquid S1 onto the gas-liquid contact layer 6 is installed in the space above it.

The operation of the digestive gas purification system will be described with reference to the system diagram of FIG. In the digestion gas purification system, the raw material gas 1 is absorbed by the gas blower 2 into the absorption tank 7
The raw material gas 1 blown into the bottom portion of 0 comes into gas-liquid contact with the absorbing liquid 80 while floating in the absorbing liquid 80 as fine bubbles 72 by the raw material gas injection pipe 71. By this gas-liquid contact, carbon dioxide gas or the like in the raw material gas 1 is absorbed into the absorbing liquid 80, and the raw material gas after absorption rises to the space 78 located above the absorption tank 70.

Further, the raw material gas 1 rising in the absorption tank 70
In order to prevent the bubbles 72 of the above from entering the circulation path 42, the tip of the circulation path is installed in the absorption liquid 80 so as to be oriented in the absorption liquid surface direction.

The treated raw material gas is introduced into the lower part of the absorption tower 7 through the gas pipe 74 connecting the absorption tank 70 and the absorption tower 7 by the blowing pressure of the gas blower 2.
The raw material gas M1 introduced into the absorption tower 7 rises in the tower and the absorption liquid S1 sprayed from the spray nozzle 5 and the gas-liquid contact layer 6
Make contact with each other. The carbon dioxide gas remaining in the raw material gas M1 is absorbed by the absorbing liquid S1 by this opposing contact, and the methane concentrated gas 9 is purified.

In the present embodiment in which the absorption tank 70 and the absorption tower 7 are connected, the number of absorption towers can be reduced instead of the double tower system, and the labor of the equipment can be reduced. Further, by using the filler 68 shown in FIG. 5 in combination, it is possible to improve the regeneration and absorption efficiency.

The configuration and operation of the digestive gas purification system will be described with reference to the system diagram of FIG. The digestion gas purification system includes an absorption tank 70, a regeneration tank 40, and a pump 24 for feeding an absorption liquid from the regeneration tank 40 to the absorption tank 70.
And a head difference flow path 46 for allowing the absorbent 80 to naturally flow from the absorption tank 70 to the regeneration tank 40. The description of the members common to the above-described embodiment will be omitted.

In the digestion gas purification system, for example, when the methane concentrated gas 9 is supplied to a small-scale fuel cell, the absorption gas from the raw material gas 1 such as carbon dioxide gas is absorbed in the absorption tank 70 before the methane concentrated gas 9 is absorbed. Purify. The absorption liquid 80 in the absorption tank 70 is allowed to naturally flow into the regeneration tank 40 through the liquid pipe 42 due to the head difference 60. In order to prevent air bubbles from being mixed into the liquid pipe 42 when the liquid is naturally flown in, the tip end portion of the liquid pipe 42 is arranged so as to be oriented in the absorbing liquid surface direction as described above.

In the digestive gas purification system, the absorption liquid 44 in the regeneration tank 40 is pumped to the absorption tank 70 by the pump 24 inserted between the liquid pipe 23 and the liquid pipe 25, so that the absorption liquid in the absorption tank 70 is absorbed. By causing the liquid level to rise above the level of the absorbing liquid 44 in the regeneration tank 40, the head difference 60 is generated.

In the present embodiment, the regeneration tank 40 and the absorption tank 7
0 is coupled, at least one pump 24 is provided only in one liquid delivery system, and the head difference flow path 46 is provided in the other liquid delivery system.
As a result of the provision of the above, the absorbing liquids 44 and 80 are circulated to each other. That is, the equipment cost is reduced by reducing the number of pumps, and no absorption tower is required. Therefore, as shown in the figure, the absorption tank 70 may be arranged on the upstream side and the regeneration tank 40 may be arranged on the downstream side. The regeneration tank 40 for raising the absorption liquid water level by the pump 24 may be arranged on the upstream side and the absorption tank 70 may be arranged on the downstream side. The point is that one of the circulation paths may be pumped and the other may be allowed to flow down the absorbent naturally by the head difference flow path.

The power generation system will be described with reference to the system diagram of FIG. The power generation system is a gas purification device 82.
And a fuel cell system 92 that uses the gas refined by the gas purifier 82 as a fuel to generate electricity by an electrochemical reaction between the fuel and the oxidant 86.

With this configuration, the gas purification system 82 according to any of the above-described embodiments is provided, so that the gas from which the acidic gas has been removed is supplied to the fuel cell system 92.
Can be supplied to the fuel cell, and uses the gas purified by the gas purification system as a fuel, and includes the fuel cell system 92 that generates electricity by the electrochemical reaction of the fuel and the oxidant. Since the heat exchanger 54 that heats the absorbing liquid with the exhaust heat generated in the battery system 92 is provided, the exhaust heat can be recovered and effectively used. The fuel cell system 92 saves time and labor for decarbonating the gas refined by the gas purifier 82 and enables highly efficient fuel cell power generation.

The power generation system inputs DC power from the fuel cell system 92 to the booster 94 and boosts it to a predetermined DC voltage. The boosted DC power is input to the DC / AC converter and converted into fixed-frequency AC power. The converted AC power is connected to the system power line 106 and the system power line 112 that are connected to the power grid 104 through the power line 108 and the connector 110. Load 1 on the grid power line 112
14 is connected.

The DC boosting and the DC / AC conversion are controlled by using the microcomputer 98 as a controller. The microcomputer has a signal control line 100
Control the fuel cell system via the signal control line 1
The DC / AC converter 96 is controlled via 02 and the booster is controlled via the signal control line 108.

The gas purification method using the digestion gas purification apparatus according to the present embodiment is a gas purification method of purifying the gas to be treated by removing the acidic gas in the gas to be treated containing the acidic gas. The step of letting the liquid flow down, the absorption step of allowing the gas to be treated to flow against the flowing absorption liquid so that the absorption liquid absorbs the acidic gas, and blowing the regeneration gas into the absorption liquid absorbing the acidic gas A regeneration step for regeneration, a circulation step for circulating the absorption liquid between the absorption step and the regeneration step, and a circulation step for flowing the absorption fluid at a water head difference between the absorption step and the regeneration step, Between the step and the regeneration step, the step of pressurizing the absorbent so as to flow from the downstream side to the upstream side of the head difference is provided.

Further, there is provided a gas purification method in which the absorbent regenerated in the regeneration step is directly supplied to the absorption step.

Further, there is also provided a gas purification method comprising a step of adjusting the temperature of the absorbing liquid supplied from the regeneration step to the absorption step at 40 ° C to 55 ° C.

[0096]

As described above, according to the present invention, a basic absorption liquid is made to flow down, and a gas to be treated is made to flow opposite to the flowing absorption liquid so that the absorption liquid absorbs acidic gas. 1
The absorption tower and the absorption liquid flowing out from the first absorption tower are arranged at positions where the absorption liquid flowing out of the first absorption tower can be introduced due to a head difference, and the absorption liquid flowing in is accumulated and the accumulated absorption liquid is regenerated by the regeneration gas. Since it has a regeneration tank for regenerating the absorption liquid that has absorbed the acidic gas and a circulation path for circulating the absorption liquid between the absorption tower and the regeneration tank, the absorption liquid that has undergone the absorption process naturally flows down to the regeneration tank. Reduce the number of pumps for absorbing liquid,
It is possible to provide a gas purification system having excellent stability in controlling the water level of the absorbing liquid.

[Brief description of drawings]

FIG. 1 is a system diagram showing a gas purification system according to a first embodiment of the present invention.

FIG. 2 is a system diagram showing a gas purification system according to a second embodiment of the present invention.

FIG. 3 is a system diagram showing a gas purification system which is a third embodiment of the present invention.

FIG. 4 is a system diagram showing a gas purification system according to a fourth embodiment of the present invention.

FIG. 5 is a system diagram showing a modified example of the gas purification system according to the embodiment of the present invention.

FIG. 6 is a system diagram showing a gas purification system which is a fifth embodiment of the present invention.

FIG. 7 is a system diagram showing a gas purification system according to a sixth embodiment of the present invention.

FIG. 8 is a system diagram showing a power generation system according to a seventh embodiment of the present invention.

FIG. 9 is a system diagram showing a conventional gas purification system.

[Explanation of symbols]

1 Raw material gas 2 gas blowers 3 liquid reservoir 4 absorbing liquid 5 spray nozzles 6 Gas-liquid contact layer 7 absorption tower 8 Purified gas piping 9 Methane concentrated gas 17 Top outlet piping 18 mixed gas 23 liquid piping 24 pumps 25 liquid piping 31 Regenerated gas 32 gas blower 40 regeneration tank 42 liquid piping 44 Absorbing liquid 46 Head difference flow path 54 heat exchanger 58 radiator 60 head difference 64a valve 64b valve 65 plumbing 66 Primary refined gas piping 68 Filler 70 absorption tank 71 Raw material gas injection pipe 74 Gas pipe 80 absorbent 82 Gas refiner 86 Oxidizing agent 92 Fuel cell system 94 Booster 96 DC / AC converter 98 microcomputer 106 grid power line 112 system power line 114 load

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomohiro Togo             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION F-term (reference) 4D020 AA03 AA04 BA19 BB03 BC01                       CB25 CC12                 5H027 AA02 BA01 BA08 KK31

Claims (5)

[Claims] 1. A gas purification apparatus for purifying a gas to be treated by removing an acidic gas in a gas to be treated containing an acidic gas; A first absorption tower in which the acidic gas is absorbed by the absorption liquid and the absorption liquid that has absorbed the acidic gas flows out by flowing processing gas in opposition; and an absorption liquid flowing out from the first absorption tower. Is a regeneration tank, which is arranged at a position where it can flow in due to a water head difference, in which the absorption liquid flowing from the first absorption tower is pooled, and a regeneration gas is blown into the pooled absorption liquid, A gas purification apparatus, comprising: a regeneration tank in which the absorption liquid that has absorbed the acidic gas is regenerated; and a circulation path that circulates the absorption liquid between the absorption tower and the regeneration tank. 2. The gas purification according to claim 1, wherein the circulation path supplies the basic absorption liquid regenerated in the regeneration tank as it is from the regeneration tank to the first absorption tower. apparatus. 3. A second absorption tower is provided which causes a basic absorbing liquid to flow down, and allows the gas to be treated to flow in opposition to the flowing absorbing liquid so that the absorbing liquid absorbs the acidic gas. The gas purification device according to any one of claims 1 to 2, wherein the first absorption tower and the second absorption tower are arranged in parallel with respect to the flow of the absorbing liquid. 4. A gas purifying apparatus for purifying a gas to be treated by removing an acidic gas in a gas to be treated containing an acidic gas; storing a basic absorbing liquid, and storing the absorbed liquid in the treated liquid. An absorption tank in which the acidic gas is absorbed in the absorption liquid by blowing gas, and the absorption liquid that has absorbed the acid gas flows out; an absorption liquid flowing out of the absorption tank flows in; A regenerator tank in which a liquid is stored and a regenerated gas is blown into the stored absorption liquid to regenerate the absorption liquid that has absorbed the acidic gas; and the absorption tank between the absorption tank and the regeneration tank. A circulation path for circulating a liquid; the circulation path has a head difference flow path for causing the absorption liquid to flow from one of the absorption tank and the regeneration tank to the other by a head difference, Upstream from the downstream tank It has a pump for sending the absorption liquid to the side tank; a gas purifier. 5. The gas purifying apparatus according to claim 1, wherein the gas purified by the gas purifying apparatus is used as a fuel, and an electrochemical reaction between the fuel and the oxidant is performed. A fuel cell system for generating power; a power generation system.