JP2021151640A - Digestion gas purification method and purification device - Google Patents

Abstract

To provide a digestion gas purification method and purification device capable of efficiently removing impurities in a digestion gas without using a robust container.SOLUTION: In the digestion gas purification method and device, a digestion gas discharged from a methane fermentation tank 1 is mixed in a gas-liquid mixing device 14 with water to produce digestion gas microbubble-containing water; the microbubble-containing water is introduced into an absorption and bubble separation column 20 and subjected to absorption and bubble separation treatment; and a purified gas is taken out of a top of the column. A water head of the absorption and bubble separation column 20 is 50 m or less. The gas-liquid mixing device 14 is positioned below a half of the water head in the vertical direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method and an apparatus for purifying digestion gas (also referred to as biogas) discharged from a methane fermentation tank that decomposes and ferments organic components by utilizing the action of anaerobic bacteria. The present invention relates to a method for removing certain sulfur compounds such as carbon dioxide, nitrogen, oxygen and hydrogen sulfide, and impurities such as siloxanes, and an apparatus thereof.

In addition to about 60% methane gas, the digestion gas contains about 30% impurities such as nitrogen, oxygen, hydrogen sulfide, and siloxane (cyclic siloxane such as D4 and D5). When a gas containing such impurities is used in a generator, sulfur and siloxane components may adhere to the combustion chamber or around the intake / exhaust valves, resulting in low combustion efficiency and damage to auxiliary equipment. , It is removed in advance using an adsorption device.

As a method for removing impurities from digestion gas, Patent Documents 1 to 3 describe a method for separating carbon dioxide and sulfur-based impurities contained in digestion gas by dissolving them in water under a pressurized atmosphere in an absorption tower. Has been done.

Japanese Patent No. 40225555 Japanese Patent No. 4088632 Japanese Patent No. 5020575 Japanese Patent No. 5112664 Japanese Patent No. 5112665 Japanese Patent No. 4344773 Japanese Patent No. 5033829 Japanese Patent No. 4959742 Japanese Patent No. 4909371 Japanese Patent No. 5181072 Japanese Patent No. 5492942 Japanese Patent No. 5492943 Japanese Patent No. 56390203

In Patent Documents 1 to 3, the absorption tower in which the pressure of high-pressure water is in the range of 0.7 to 1.0 MPaG must be a sturdy container capable of withstanding high pressure, and the gas introduced under high-pressure conditions must be used. There is a problem that the bubble diameter becomes large and the dissolution efficiency does not increase.

An object of the present invention is to provide a digestion gas purification method and a purification apparatus capable of efficiently removing impurities in the digestion gas without using a sturdy container.

In the method for purifying digestion gas of the present invention, the digestion gas discharged from the methane fermentation tank and water are mixed in advance in a gas-liquid mixer to generate fine bubble-containing water of the digestion gas, and the fine bubble-containing water is produced. It is introduced into an absorption / bubble separation tower to absorb and recover impurities on the water side, and a component insoluble in water is subjected to bubble separation treatment, and purified gas is taken out from the top of the tower.

In one aspect of the method for purifying digestive gas of the present invention, the head of the absorption / bubble separation tower is 50 m or less, and the gas-liquid mixing device is arranged below the middle of the water head in the vertical direction.

In one aspect of the digestion gas purification method of the present invention, the pH of the fine bubble-containing water introduced into the absorption / bubble separation tower, the water in the absorption / bubble separation tower, or the water discharged from the absorption / bubble separation tower. Is 4.8 or more.

In one aspect of the digestion gas purification method of the present invention, the water temperature of the water introduced into the gas-liquid mixing device or the water in the absorption / bubble separation tower is set to 60 ° C. or lower.

In one aspect of the method for purifying digestive gas of the present invention, the diameter of bubbles of the fine bubble-containing water flowing out from the gas-liquid mixing device is set to 100 μm or less.

In one aspect of the method for purifying digestion gas of the present invention, water discharged from the absorption / bubble separation tower is introduced into a water tank separately provided and irradiated with light having a wavelength of 400 to 800 nm to algae or aquatic plants. To absorb carbon dioxide or sulfur components.

In one aspect of the method for purifying digestion gas of the present invention, digestive sludge discharged from the methane fermentation tank or a dehydration filtrate thereof is added to the water tank or the water discharged from the absorption / bubble separation tower introduced into the water tank.

The digestion gas purification device of the present invention is a gas-liquid mixing device for mixing digestion gas and water to obtain fine bubble-containing water, and absorption / absorption in which fine bubble-containing water is introduced from the gas-liquid mixing device. It has a bubble separation tower, and purified digestion gas is taken out from the top of the absorption / bubble separation tower.

In one aspect of the digestion gas purification apparatus of the present invention, a water tank into which the water discharged from the absorption / bubble separation tower is introduced, and a means for irradiating the water in the water tank with light having a wavelength of 400 to 800 nm are further provided. Have.

In one aspect of the digestion gas purification apparatus of the present invention, there is a means capable of removing carbon dioxide in the discharged water from the absorption / bubble separation tower.

In one aspect of the digestion gas purification apparatus of the present invention, the gas-liquid mixer is particularly a static mixer, a dynamic mixer, a venturi, an ejector, or a cavitation nozzle, or a gas permeable membrane. be.

In one aspect of the digestion gas purification apparatus of the present invention, the gas-liquid mixer is composed of two or more devices of the same type, particularly selected from a static mixer, a dynamic mixer, a venturi, an ejector, a cavitation nozzle, or a gas permeable membrane. It is installed in series with respect to the flow path direction.

In one aspect of the digestion gas purification apparatus of the present invention, the gas-liquid mixing apparatus is composed of two or more different types of apparatus in which the gas-liquid mixer is particularly selected from a static mixer, a dynamic mixer, a venturi, an ejector, a cavitation nozzle, or a gas permeable membrane. It is arranged in series with respect to the flow path direction.

In one aspect of the digestion gas purification device of the present invention, a plate-shaped obstacle or a three-dimensional obstacle due to a filling is installed inside the gas-liquid mixing device. In the case of a plate-shaped obstacle, it has an oblique angle and has holes through which water and gas can pass through the plate. It has an inlet / outlet structure that allows water and gas to pass through even in the case of a three-dimensional obstacle due to the filling.

In the present invention, by mixing the digestion gas and water in advance in the gas-liquid mixer, the digestion gas is made into fine bubbles to remarkably increase the contact area of the gas-liquid, and the subsequent interior is weakly pressurized. In the absorption / bubble separation tower, the bubbles do not rise sharply and slowly float in the water, so that the residence time can be lengthened and the efficiency of dissolving impurities in the digestion gas in water can be significantly improved.

In a conventional general air diffuser, an air diffuser or a membrane is submerged in or under the water tank, and the supplied gas is ejected from the pipe or membrane.
The bubble diameter varies depending on the size of the ejection hole, but the bubble diameter in the water discharged in a water tank having a depth of several meters is about 2 mm, so that the bubbles rise at a speed of several tens of centimeters per second. Further, if an air diffuser that generates finer bubbles is used, a size of about 200 μm can be obtained, and the floating speed of the bubbles can be reduced to about a dozen cm per second. However, in the method of dissipating air in the water tank, when the water depth becomes deep, the air supply pressure is required to overcome the water pressure, so the bubble size becomes large and the surface area becomes small, and the ascent speed is high. Therefore, there is a problem that the dissolution efficiency is poor because the residence time is shortened and the contact time with water is shortened. Increasing the water pressure can be expected to increase the amount of gas that can be dissolved on the water side, but it is difficult to increase the efficiency due to the problem of the bubble diameter that can be generated.
In addition, the dissolution efficiency is increased by increasing the number of bubbles to be generated, but if a certain condition is exceeded, the gas dissolved in the water may be expelled by the bubbling effect and the dissolution efficiency may decrease. Control was more difficult at higher pressures.

When the bubble diameter is 1 μm, the total surface area of gas-liquid contact is 200 times that of 200 μm. If the bubble diameter is 0.2 μm, the total surface area will be 2000 times larger. Therefore, even if the water pressure is several times higher than the atmospheric pressure, the same dissolution efficiency as that of high-pressure water can be obtained. According to the present invention, carbon dioxide, oxygen, and hydrogen sulfide can be efficiently dissolved in water and removed from digestion gas to increase the purity (concentration) of methane gas. As described above, it is difficult to blow gas into a high-pressure water tank to generate fine bubbles, but by dissolving the gas in water introduced into the water tank in advance with a gas-liquid mixer and creating fine bubbles, the above-mentioned Can solve problems such as.

Even if fine bubbles are physically formed by the gas-liquid mixer, the efficiency decreases if there is a pressure difference from the discharge side. If the pressure on the discharge side is extremely high, the bubbles gather together before the fine bubbles dissolve and disappear, and the bubble diameter becomes large, so that the expected dissolution efficiency may not be obtained. If the pressure on the discharge side is extremely low, the internal pressure of the formed fine bubbles decreases, and even in this case, the bubbles gather together and the bubble diameter becomes large, so that the expected dissolution efficiency may not be obtained. Therefore, by installing the gas-liquid mixing device below half of the head of the absorption / bubble separation tower (middle in the vertical direction), the pressure difference between the inlet side and the discharge side of the device can be reduced. In addition, since a nearly constant pressure can be applied at all times, even if the flow rate or pressure of the introduced water or gas changes, the pressure fluctuation in the device and on the outlet side can be suppressed, and this problem can be solved. It is possible.

Of the impurities contained in the digestion gas, carbon dioxide and hydrogen sulfide are more easily dissolved in water as the pH is higher, so the pH of the discharged water in the absorption / bubble separation tower or from the absorption / bubble separation tower is 4.8. It is preferable to maintain the above. Further, by adjusting the pH of water to the alkaline side, the solubility in water is increased, and it is possible to shift to the aqueous phase and improve the separation efficiency from the gas. In particular, the existence form of carbon dioxide changes depending on the pH, but by adjusting the pH to 8.3 or higher, it is possible to prevent the transition (reverse) to the gas phase side even if bubbling is received.

The solubility of gas in water is higher as the water temperature is lower. In particular, carbon dioxide is significantly less soluble when the water temperature exceeds 60 ° C. Therefore, the water temperature of the water supplied to the absorption / bubble separation tower or the gas-liquid mixer Is preferably maintained at 60 ° C. or lower. In particular, since the dissolution rate is remarkably improved when the temperature is lower than 20 ° C, it is preferable to operate at 20 ° C or lower.

A general-purpose heat exchanger can be used to control the water temperature.

As described above, the solubility in water can be increased by generating fine bubbles in the gas-liquid mixer, but when bubbles with a large diameter are mixed, the fine bubbles adhere and float, or inside the bubbles. It is preferable to select a gas-liquid mixer having a performance capable of reducing the bubble diameter to 100 μm or less. In addition, since the diameter of the generated bubbles changes depending on the mixing ratio and pressure difference between water and gas, the operating conditions suitable for the selected gas-liquid mixing device, and the pH and water temperature have changed, and the viscosity of the water has changed. Sometimes it is preferable to operate at an appropriate value. In an environment where the fluctuation of each element is large, it is more preferable to provide an automatic control device.

The water discharged from the absorption / bubble separation tower is rich in carbon dioxide. Therefore, the effluent from the absorption / bubble separation tower may be introduced into the aquarium so as to be absorbed by algae and aquatic plants that propagate in the water. Carbon dioxide can be efficiently temporarily fixed by irradiating this aquarium with light containing light having a wavelength of 400 to 800 nm, such as direct sunlight or artificial light on which plants can easily grow. If you cultivate a kind of algae that stores fats and oils, you can obtain bio-oil, and other algae and aquatic plants can be reused as raw materials for methane fermentation. Can be done.

Also, algae and aquatic plants may require nitrogen and phosphorus to grow. Therefore, by introducing the digestive juice discharged from the methane fermentation tank or the dehydrated filtrate discharged when the digestive juice is dehydrated into the above water tank, nitrogen and phosphorus can be replenished and cultivation is promoted. can do.

The water used for cultivation has a low carbon dioxide concentration, so it can be reused for refining digestion gas.

By passing the discharged water from the absorption / bubble separation tower, which is rich in carbon dioxide, through a decarboxylation device, the carbon dioxide concentration can be sufficiently reduced, so it can be reused for purification of digestion gas. It is possible.
Examples of the decarboxylation device include a method of adjusting the pH of the discharged water to the acidic side and then dropping / spraying it from the upper part of the filling (decarboxylation tower), a membrane decarboxylation device using a gas permeable film, and a vacuum decarboxylation device. For example, existing methods can be applied.

It is a block diagram of the digestion gas purification apparatus which concerns on embodiment. It is a block diagram of the absorption / bubble separation tower.

Hereinafter, embodiments will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, substrate-containing substances (sewage sludge, human waste, livestock manure, kitchen waste, food residue or fermentation residue from food processing factories and eating and drinking facilities, sugar-making residue, paper, agricultural and fishery waste, grass cutting and pruned trees, etc. Collection of waterweeds, waste oil and grease trap collection oil, raw milk and dairy products collection, alcohol and soft drink collection, crude glycerin (BDF by-product), biodegradable plastic waste collection, etc.) It is put into 1 and a fermentation reaction is carried out to generate digestive gas and digestive juice. The digestive juice is sent to the dehydrator 2, dehydrated, and separated into a dehydrated cake and a dehydrated filtrate. The dehydrator is not particularly limited, and various types can be used.

The digestion gas is introduced from the methane fermentation tank 1 into the gas tank 3 and stored. A pressure gauge 4 is provided in the gas tank 3, and the gas transfer pump 5 is operated according to the detected pressure of the pressure gauge 4.

In particular, when the gas tank 3 is a variable volume type gas holder, the holding volume of gas can be substituted, and the gas transfer pump 5 is operated in response to a signal of a gas volume detector (not shown). You may do so.

The digestion gas in the gas tank 3 is sent to the pipe 13 via the pump 5 and the pipe 6.

The gas water absorption water is supplied from the pump 11 to the pipe 13 and sent to the heat exchanger 7, preferably cooled to 60 ° C. or lower, particularly 20 ° C. or lower, for example, 10 to 20 ° C., and then via the check valve 12. After that, it merges with the digestion gas from the pipe 8 in the pipe 13 and is introduced into the gas-liquid mixing device 14 (here, a static mixer).

Further, in the pipe 13, an alkali such as an aqueous NaOH solution is added by the adding means 10. In the piping static mixer 14, a part of the digestion gas is directly dissolved in the gas absorption water, and most of the digestion gas is mixed as fine bubbles in the gas absorption water. In addition, a part of the digestion gas becomes undissolved and is discharged as a gas together with water.

The fine bubble-containing water from the static mixer 14 is introduced into the lower part of the absorption / bubble separation tower 20 via the injection section 15. The absorption / bubble separation tower 20 includes legs 20a.

An inclined plate 21b made of a rod-shaped screen is installed as an obstacle in the lower part of the absorption / bubble separation tower 20, and the injection portion 15 is arranged below the inclined plate 21b. The inclined plate 21b guides bubbles that have not become fine bubbles to the outer peripheral portion of the tower and allows them to be discharged promptly, thereby preventing bubbling in the tower. Water containing the bubbles may be separated and discharged from the absorption / bubble separation tower and returned to the upstream side of the gas-liquid mixing device to perform the dissolution treatment again.

An overflow weir 22 is provided above the absorption / bubble separation tower 20, and water overflows the overflow weir 22 and flows out to the pipe 23. The upper end level of the overflow weir 22 is the water level in the absorption / bubble separation tower 20.

An inclined plate 21a made of a mesh screen is installed below the upper water surface position in the absorption / bubble separation tower 20. Methane that has become fine bubbles is collected by the inclined plate 21a, and large bubbles are formed on the surface of the inclined plate 21a to facilitate separation from gas absorption water and improve the recovery rate.

In such a form in which the inclined plate 21a and the inclined plate 21b are installed, the hole diameter or the groove width (slit width) of the inclined plate 21a is naturally smaller (narrower) than that of the inclined plate 21a.

In the embodiment of the present invention, a rod-shaped screen having a mesh width of 1 mm is used for the inclined plate 21b, and a mesh screen having a mesh width of 0.109 mm (150 mesh) is used for the inclined plate 21a. A punching plate may be used instead of the rod-shaped screen or the mesh screen, or a filling layer loaded with the filling may be provided.

As shown in FIG. 2, the height H from the bottom of the absorption / bubble separation tower 20 to the water surface level is the head of the absorption / bubble separation tower 20. A head H of 50 m or less is sufficient, and is set to 10 m in the examples.

The installation height h (height from the bottom of the absorption / bubble separation tower) of the static mixer 14 is preferably H / 2 or less, and the static mixer 14 can be installed near the bottom. In the example, it was arranged at the position of h = 50 cm.

A pipe 24 for taking out purified gas is connected to the top of the absorption / bubble separation tower 20, and the refined gas is sent to a gas tank (not shown).

In the digestion gas refining apparatus configured as described above, the digestion gas generated in the methane fermentation tank 1 flows through the gas tank 3, the pump 5, the pipe 6, the check valve 9, and the pipe 8 and flows into the pipe 13. Then, it is introduced into the static mixer 14 together with the water for gas absorption, and the generated fine bubble-containing water is introduced from the injection unit 15 to the lower part in the absorption / bubble separation tower 20. While the water containing fine bubbles rises in the absorption / bubble separation tower 20, impurities such as carbon dioxide and hydrogen sulfide in the digestion gas dissolve in the water and are removed from the digestion gas.

When impurities are dissolved and removed in water and sufficiently purified bubbles reach the water level in the absorption / bubble separation tower 20, the purified gas separates from the water to the gas phase part at the top of the tower for purification. Gas is taken out of the pipe 24.

Since the discharged water discharged from the pipe 23 contains abundant carbon dioxide, it is introduced into a cultivation tank in which algae and aquatic plants are grown, and artificial light containing sunlight and a wavelength of 400 to 800 nm is applied to the water in the tank. May be fixed by irradiating the water with carbon dioxide absorbed by algae and aquatic plants.

Further, a part of the digestive juice from the methane fermentation tank 1 and the dehydration filtrate from the dehydrator 2 may be added to the cultivation tank or the inflow pipe to the cultivation tank to replenish the nitrogen and phosphorus components. Since the effluent from the cultivation tank has a low carbon dioxide concentration, it may be reused as water for gas absorption.

The discharged water from the pipe 23 may be decarboxylated by a decarboxylation tower or a decarboxylation membrane device and reused.

Although the pipe 8 is directly connected to the pipe 13 in FIG. 1, an ejector may be installed in the pipe 13 and the pipe 8 may be connected to the ejector.

[Example 1]
The specifications and operating conditions of the purification equipment shown in FIG. 1 were as follows, and the following good results were obtained.

Absorption / bubble separation tower: 100A-SUS pipe x 11m (excluding leg dimensions)
Head H = 10m
Static mixer: SSM type static mixer manufactured by Shinyu Giken Co., Ltd. Installation position (height) h = 50 cm
PH in absorption / bubble separation tower 20: 8.3
Water temperature in the absorption / bubble separation tower 20: 20 ° C
Bubble size (center diameter) in the absorption / bubble separation tower 20: 10 μm
Amount of water for gas absorption = 10 L / min (pressure = 0.5 MPa)
Supply digestion gas amount = 2NL / min (pressure = 0.5MPa)
Digestive tank volume: 2,000 m ³
Substrate input to digestive tank: Sewage sludge (TS concentration = 3.2%)
・ Initial sludge: Exclusion method = confluence method, concentration method = gravity concentration
・ Excess sludge: Treatment method = standard activated sludge method, concentration method = mechanically concentrated sewage sludge ^{generated when 100 m 3} / day is added: 1,800 Nm ³
Composition of digestive gas: methane = 60%, CO ₂ = 33%, N2 = 5%,
O ₂ = 1.5%, H ₂ S = 740 ppm
Composition of refined gas: methane = 92%, CO ₂ = 1%, N ₂ = 7%,
O ₂ <1%, H ₂ S <20 ppm

[Comparative Example 1]
When the digestion gas was purified under the same conditions as in Example 1 except that the installation height h of the static mixer 14 was 7 m, the composition of the purified gas was methane = 78%, CO ₂ = 16%, N ₂ =. 7%, O ₂ <1%, H ₂ S <370 ppm, and the purity decreased.

[Example 2]
The same conditions as in Example 1 were set except that the installation height h of the static mixer 14 was set to 3 m and the pH in the absorption / bubble separation tower 20 was set to 6.2, 7.1, 8.3 or 9.2. .. As a result, the CO ₂ concentration in the purified gas is
27% when pH = 6.2
12% when pH = 7.1
1% when pH = 8.3
When pH = 9.2 <1%
It was found that the higher the pH, the lower _{the CO 2 concentration in the purified gas.}
In particular, when the pH was 8.3 or higher, the concentration in the purified gas was 1% or less, and it was confirmed that the purity of the methane gas was high.

[Example 3]
The conditions are the same as in Example 1 except that the installation height of the static mixer 14 is 3 m and the water temperature in the absorption / bubble separation tower 20 is 10 ° C, 20 ° C, 30 ° C, 40 ° C, 50 ° C or 60 ° C. bottom. As a result, the CO ₂ concentration in the warm purified gas is
At 10 ° C <1%
5% at 20 ° C
18% at 30 ° C
24% at 40 ° C
28% at 50 ° C
30% at 60 ° C
It was found that the lower the water temperature in the absorption / bubble separation tower, the lower the CO ₂ concentration in the purified gas.

[Example 4]
Except that the installation height of the static mixer 14 was set to 3 m and the bubble size (center diameter) in the absorption / bubble separation tower 20 was set to 0.5, 1, 10, 100 or 200 μm by exchanging the model of the static mixer. Was the same as in Example 1. As a result, the CO ₂ concentration in the purified gas is
In the case of 0.5 μm <1%
1% for 1 μm
5% for 10 μm
23% for 100 μm
30% for 200 μm
It was confirmed that the smaller the bubble size, the lower the CO _{2 concentration in the purified gas.}

1 Methane fermenter 2 Dehydrator 7 Heat exchanger 14 Gas-liquid mixer (static mixer)
15 Injection part 20 Absorption / bubble separation tower

Claims (14)

The digestion gas discharged from the methane fermenter is mixed with water in a gas-liquid mixer to generate water containing fine bubbles of digestion gas.
A method for purifying digestion gas, in which the water containing fine bubbles is introduced into an absorption / bubble separation column to be absorbed and bubble-separated, and the purified gas is taken out from the top of the column. In the method for purifying digestion gas according to claim 1, the head of the absorption / bubble separation tower is 50 m or less.
A method for purifying digestive gas, which comprises arranging the gas-liquid mixing device below the middle of the water head in the vertical direction. In the method for purifying digestion gas according to claim 1 or 2, the water containing fine bubbles introduced into the absorption / bubble separation tower, the water in the absorption / bubble separation tower, or the water discharged from the absorption / bubble separation tower. A method for purifying digestive gas, which comprises setting the pH of the above to 4.8 or higher. The method for purifying a digestive gas according to any one of claims 1 to 3 is characterized in that the water temperature of the water introduced into the gas-liquid mixer or the water in the absorption / bubble separation tower is 60 ° C. or lower. How to purify digestive gas. The method for purifying digestive gas according to any one of claims 1 to 4, wherein the diameter of the bubbles of the fine bubble-containing water flowing out from the gas-liquid mixing device is 100 μm or less. In the method for purifying digestion gas according to any one of claims 1 to 5, water discharged from the absorption / bubble separation tower is introduced into a water tank and irradiated with light having a wavelength of 400 to 800 nm to algae or aquatic plants. A method for purifying digestive gas, which comprises allowing algae to absorb carbon dioxide or sulfur components. The method for purifying digestion gas according to claim 6 is characterized in that the digested sludge discharged from the methane fermentation tank or the dehydrated filtrate thereof is added to the water tank or the water discharged from the absorption / bubble separation tower introduced into the water tank. A method for purifying digestive gas. A gas-liquid mixer for mixing digestion gas and water to obtain fine bubble-containing water,
A digestion gas purification device having an absorption / bubble separation tower into which fine bubble-containing water is introduced from the gas-liquid mixing device, and extracting purified digestion gas from the top of the absorption / bubble separation tower. In the digestion gas purification apparatus of claim 8, the water tank into which the discharged water from the absorption / bubble separation tower is introduced, and
A digestion gas purification device further comprising a means for irradiating the water in the aquarium with light having a wavelength of 400 to 800 nm. The digestion gas purification apparatus according to claim 8 or 9, further comprising means for removing carbon dioxide contained in water discharged from the absorption / bubble separation tower. The digestion gas purification apparatus according to any one of claims 8 to 10, wherein the gas-liquid mixer is a static mixer, a dynamic mixer, a venturi, an ejector, a cavitation nozzle, or a gas permeable membrane. Gas refiner. In the digestion gas purification apparatus according to any one of claims 8 to 10, two or more selected as the gas-liquid mixing apparatus from a static mixer, a dynamic mixer, a venturi, an ejector, a cavitation nozzle, and a gas permeable membrane. A digestion gas purification device characterized in that gas-liquid mixers of the same type are installed in series in the flow path direction. In the digestion gas purification apparatus according to any one of claims 8 to 10, two or more selected as the gas-liquid mixing apparatus from a static mixer, a dynamic mixer, a venturi, an ejector, a cavitation nozzle, and a gas permeable membrane. A digest gas purification device characterized in that different types of gas-liquid mixers are arranged in series in the flow path direction. The digestive gas refining apparatus according to any one of claims 8 to 13, characterized in that a plate-shaped obstacle or a three-dimensional obstacle due to a filling is installed inside the gas-liquid mixing apparatus. Digestion gas purification equipment.

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