KR20050092273A - Fermentative hydrogen production from organic wastewater using gas sparging and the fermenting device - Google Patents

Abstract

The present invention provides a method for producing hydrogen, characterized in that hydrogen is produced from carbohydrates of organic wastewater by sparging organic wastewater in a fermenter with carbon dioxide gas.

In addition, the present invention is the inlet water supply unit for supplying the organic wastewater into the fermentation tank, the outflow water outlet for discharging the organic wastewater treated in the fermentation tank, a pH control unit for adjusting the pH in the fermentation tank, a porous plate for gas sparging is installed at the bottom In the hydrogen fermentation apparatus including a fermentation tank, a hydrogen recovery unit for recovering hydrogen gas generated in the fermentation tank, the hydrogen recovery unit gas discharge line 14 for discharging the primary gas generated in the fermentation tank, the primary gas The primary gas generation meter 10 for collecting and measuring the amount of gas generated, the gas separation membrane 21 for passing only hydrogen gas in the primary gas, and discharged from the primary gas generation meter to apply pressure to the gas separation membrane. Decompression pump (7) for decompressing the gas, the hydrogen gas separated from the gas separation membrane 21 is collected through a hydrogen recovery line (19) Hydrogen generation amount measuring instrument 10 'capable of measuring the amount of hydrogen generated and secondary gas excluding the hydrogen gas in the primary gas to the porous plate 8 through the secondary gas injection line 12 It provides a hydrogen fermentation apparatus comprising a gas flow control system (11).

Description

Fermentative Hydrogen Production from Organic Wastewater Using Gas Sparging and The Fermenting Device}

The present invention relates to a method for producing hydrogen from carbohydrates of organic wastewater, and more particularly, a method for producing hydrogen with economical, stable and high efficiency compared to the conventional anaerobic hydrogen fermentation method, and the biogas produced in the fermentation tank (1 By recovering carbon dioxide from the secondary gas) and supplying it to the sparging gas (secondary gas), the present invention relates to a hydrogen fermentation apparatus that eliminates the burden of additional costs associated with purchasing an external gas and removes the hassle of purifying hydrogen.

The production of hydrogen by microorganisms has been well known since the early 1900s, but has not attracted much attention. However, due to the global warming caused by the recent increase in the use of fossil fuels along with the petroleum surge in the 1970s, much attention has been focused on the production of hydrogen that can be used as an alternative energy source. When hydrogen is used as a fuel, it has the advantages of being environmentally friendly, producing only water as a by-product of combustion, and having higher energy content and conversion rate than general hydrocarbon compounds (see Ramanchandran et al., Int. J. Hydrogen Energy, vol. 23). (7), 1998, p. 593-598).

The method of producing hydrogen is divided into physical and chemical methods and biological methods. The physical and chemical methods require a lot of energy using fossil fuels to produce hydrogen, and thus are not environmentally friendly. In addition, biological methods include photosynthesis and anaerobic fermentation. Photosynthesis requires a light source, a slow reaction rate, and high activation energy for hydrogen generation. Anaerobic fermentation can produce hydrogen through the decomposition of carbohydrates, which is a major component of waste, which can reduce the amount of waste. Has advantages (see Zaborsky, Biohydrogen, Plenum Press, Newyo and London, 1998. p. 10-17).

The process of producing hydrogen by anaerobic fermentation is similar to that of acid production in relatively well known anaerobic digestion, but until now conditions for optimal hydrogen production have not been established, producing hydrogen with satisfactory stability and high yield. The method is not reported. In particular, studies on continuous experiments using mixed wastewater and actual wastewater for practical wastewater treatment are more incomplete. Therefore, recently, in order to solve such problems, researches on optimal pH, hydraulic retention time, concentration of organic matter, etc. have been conducted in order to maintain appropriate environmental conditions for Clostridia during anaerobic fermentation using a mixed culture broth. (Hawkes et al., Int. J. Hydrogen Energy, vol. 27, 2002, p. 1339-1347). Hydrogen partial pressure in the reactor is also a factor influencing hydrogen production, and many studies have been conducted. Generally, a low hydrogen partial pressure has a good effect on hydrogen production (see Chung .. KT, Appl. Env. Microbiol., vol. 31 (3), 1976, p. 342-348, Andel et al., Appl. Microbiol. Technol., vol. 23, 1985, p. 21-26).

Gas sparging is a hydrogenase that contributes to hydrogen production by lowering the concentration of hydrogen in the liquid phase, along with the physical aspects of enhancing the overall agitation effect to facilitate contact with the substrate and releasing the generated hydrogen into the gas phase. In the existing continuous experiments, there was a report that the hydrogen production rate is improved when sparging with nitrogen is a method that enables continuous and high hydrogen production in the biological aspect that the enzyme activity is not inhibited by high concentration of hydrogen. (See Mizuno et al., Bioresource Technol., Vol. 73, 2000, p. 59-65). In addition, hydrogen production has been reported to be improved in batch experiments using nitrogen or argon as sparging gases. See Tashino et al., Int. J. Hydrogen Energy., Vol. 23 (7), 1998, p. 559-563).

However, according to the hydrogen production technology to date using the above gases, the hydrogen conversion rate is still low, and the problem of lack of economy is not solved.

The present invention has been made to solve the problems of the prior art, the object is to provide a method for producing hydrogen with economical, stable and high efficiency compared to the conventional anaerobic hydrogen fermentation method.

Another object of the present invention is to provide a method for producing hydrogen capable of producing a large amount of hydrogen through gas sparging only without a separate mechanical stirring process.

Another object of the present invention is to recover the carbon dioxide gas from the biogas (primary gas) produced in the fermenter and to supply it as a sparging gas (secondary gas) in the fermenter to reduce the burden of additional costs associated with the purchase of external gas In addition, the present invention provides a hydrogen fermentation apparatus that eliminates the need to purify hydrogen.

In order to achieve the above object, the present invention provides a method for producing hydrogen by hydrogen fermentation, by sparging the organic wastewater in the fermenter with carbon dioxide gas to produce a hydrogen gas from the carbohydrate of the organic wastewater. To provide.

The present invention preferably provides a method for producing hydrogen, wherein the carbon dioxide gas is recovered from the biogas generated in the reaction tank.

The present invention preferably provides a method for producing hydrogen, characterized in that the sparging of the carbon dioxide gas is carried out at a flow rate of 250 ~ 350ml / min.

The present invention preferably provides a method for producing hydrogen, characterized in that the fermentation reaction is carried out at pH 5.3 ± 0.1, temperature 35 ± 1 ℃.

In addition, the present invention is an inlet water supply unit for supplying organic wastewater into the fermentation tank, an effluent outlet for discharging the organic wastewater treated in the fermentation tank, a pH control unit for adjusting the pH in the fermentation tank, fermentation tank is installed in the lower part for sparging In the hydrogen fermentation apparatus comprising a hydrogen recovery unit for recovering the hydrogen gas generated in the fermentation tank,

The hydrogen recovery unit gas discharge line 14 for discharging the primary gas generated in the fermentation tank, the primary gas generation meter 10 for collecting the primary gas and measure the amount of gas generated, hydrogen in the primary gas A gas separation membrane 21 for passing only gas, a pressure reducing pump 7 for reducing the pressure of the gas discharged from the primary gas generation meter to apply pressure to the gas separation membrane, and hydrogen gas separated from the gas separation membrane 21 The secondary gas injection line 12 collects a hydrogen generation amount measuring instrument 10 'capable of measuring the amount of hydrogen gas collected through the recovery line 19 and collecting the secondary gas excluding the hydrogen gas in the primary gas. It provides a hydrogen fermentation apparatus, characterized in that it comprises a secondary gas flow control system (11) for supplying to the porous plate (8) through.

The present invention preferably provides a hydrogen fermentation apparatus, characterized in that a water vapor removal filter 20 for preventing the penetration of water vapor in the gas separation membrane 21 is further included in front of the inlet of the gas separation membrane.

Hereinafter, the content of the present invention in more detail as follows.

Anaerobic hydrogen fermentation bacteria used for hydrogen fermentation is preferably used anaerobic sludge obtained from a sewage treatment plant rather than using pure culture bacteria, by applying heat treatment to the anaerobic sludge to remove the inhibitory action by hydrogen consuming bacteria such as methane-producing bacteria It is better to use the obtained mixed culture bacteria. At this time, the heat treatment condition does not require a special limitation, but preferably 10 to 20 minutes at 90 ~ 100 ℃.

In order to maintain an optimal environment for hydrogen production, it is recommended to keep the pH at 5.3 ± 0.1 and the temperature at 35 ± 1 ℃. In this case, stirring is not particularly required, but in the case of stirring, the hydraulic residence time (HRT) is preferably 10 to 14 hours, more preferably 60 to 120 rpm, more preferably 100 rpm. 12 hours. In the embodiment of the present invention, the effective volume of the reaction tank was 5L, and an example of operating in a completely mixed mode is presented, but this is only presented to help the understanding of the present invention and there is no reason to be limited thereto.

When carbon dioxide is used as the sparging gas, it is possible to obtain a higher hydrogen conversion rate than when using other gases. The high partial pressure of carbon dioxide is formed in the fermenter, and it produces little acetic acid or consumes hydrogen to produce acetic acid with little inhibitory effect on Clostridia, a major hydrogen producing bacterium. It appears to be due to the inhibitory effect on the microorganisms in competition.

Optimum sparging conditions are not particularly limited, but preferably performed at a flow rate of 250-350 ml / min, more preferably 300 ml / min, yielding hydrogen conversion per glucose injected or degraded. It is highest.

Hereinafter, a hydrogen fermentation apparatus and action for implementing the hydrogen production method will be described with reference to the drawings.

1 is a schematic configuration diagram of a hydrogen fermentation apparatus using carbon dioxide gas as a sparging source as a preferred embodiment of the present invention. The apparatus includes an inlet water supply unit for supplying organic wastewater into the fermentation tank, an effluent outlet for discharging organic wastewater treated in the fermentation tank, a pH control unit for adjusting pH in the fermentation tank, a fermentation tank having a porous plate for gas sparging at the bottom thereof, Hydrogen recovery unit for recovering the hydrogen gas generated in the fermentation tank.

The influent feed part is a feed part of the organic wastewater into the fermentation tank, and preferably includes an influent sump tank 2, an influent pump 9 and an influent line 16. Organic wastewater (planting wastewater) is stored in the influent collection tank 2 and is introduced into the fermentation tank 1 via the inlet line 16 by a pump 9.

The effluent discharge part is for discharging the organic wastewater from which the fermentation is completed out of the fermentation tank, and preferably includes an effluent pump 9 ', an effluent line 17 and an effluent collection tank 3. The organic wastewater introduced into the fermentation tank 1 is discharged to the effluent collection tank 3 through the effluent line 17 by the pump 9 'after the hydraulic residence time (HRT) has elapsed.

pH control unit for adjusting the pH in the fermenter, a pH meter (5) for measuring the pH in the fermenter, a pH controller (6) connected to the pH meter to maintain a constant pH in the fermenter, injected to maintain the pH A water collecting tank 4 containing a pH adjusting liquid (for example, 3 M potassium hydroxide solution), an inflow line 18 of the pH adjusting liquid, and the pH adjusting liquid are supplied into the fermenter, and controlled by a pH controller 6. Pump 9 ".

If the pH controller 6 determines that the pH in the fermenter as measured by the pH meter 5 is out of the normal operating range, the pH controller 6 controls the pump 9 "to adjust the pH control liquid in the sump 4. Into the fermenter it is preferably controlled to a certain amount based on the stoichiometry.

The fermentation tank 1 is a place for fermenting the introduced organic wastewater during the hydraulic retention time (HRT), and a lower plate (or acid substrate) 8 is installed at the lower part for sparging carbon dioxide gas. The structure of such a porous plate is already well known. In addition, the fermentation tank may further include a stirrer 22 for mechanically stirring the fermentation broth. However, in the case of using carbon dioxide as a sparging gas according to the present invention, it is not necessary to further install the above agitator.

The sparging gas is filled in the gas cylinder 23 and supplied to the porous plate 8 through the gas injection line 12 through the gas flow control system 11.

The hydrogen recovery unit for recovering the hydrogen gas generated in the fermentation tank 1 preferably includes a gas discharge line 14 and a wet gas meter 15 for measuring the amount of gas generated. Preferably, the gas sampling port 13 capable of measuring the degree of purification of hydrogen is connected to the gas discharge line.

The hydrogen recovery unit is more preferably provided as an organically coupled structure to perform the function of supplying the sparging gas from the biogas (primary gas) generated during fermentation into the fermenter and the collection function of hydrogen gas at the same time.

The structure shown as a preferred embodiment for the hydrogen recovery unit is shown in Figure 3, a gas discharge line 14 for discharging the primary gas generated in the fermenter, collecting the primary gas and measuring the amount of gas generated A primary gas generation meter (10) capable of, a gas separation membrane (21) for passing only the hydrogen gas in the primary gas, a pressure reducing pump for reducing the gas discharged from the primary gas generation meter to apply pressure to the gas separation membrane (7), a hydrogen generation amount measuring instrument 10 'capable of collecting the hydrogen gas separated from the gas separation membrane 21 through a hydrogen recovery line 19 and measuring the generated amount of the collected hydrogen gas, and the primary gas It includes a secondary gas flow control system 11 for supplying the secondary gas excluding the hydrogen gas to the porous plate 8 through the secondary gas injection line 12.

Referring to FIG. 3, the primary gas generated in the fermenter includes carbon dioxide and hydrogen gas, and the primary gas is introduced into the primary gas generation meter 10 through the gas discharge line 14. The primary gas generation meter 10 may collect the primary gas and measure the gas generation amount. The primary gas is introduced into the gas separation membrane 21 via the water vapor removal filter 20 in a pressure-reduced state by the pressure reducing pump 7. The steam removal filter 20 may be installed to prevent infiltration of water vapor in the gas separation membrane 21.

The gas separation membrane 21 should be able to selectively pass only hydrogen to the hydrogen recovery line 19. For example, commercially available products include palladium having a property of selectively adsorbing hydrogen only from REB Research & Consulting Co., Ltd. Membranes made with the addition of some silver or Mr Hydrogen membranes from the same company can be used. Hydrogen gas is introduced into the hydrogen generation meter (10 ') through the gas separation membrane (21). The hydrogen generation amount measuring instrument 10 ′ may collect the hydrogen gas separated from the gas separation membrane 21 through the hydrogen recovery line 19 and measure the amount of hydrogen gas collected. The primary gas generation amount measuring instrument 10 and the hydrogen generation amount measuring instrument 10 'is preferably a level displacement type gas generating amount measuring instrument.

On the other hand, the secondary gas (containing carbon dioxide) excluding the hydrogen gas in the primary gas is supplied to the porous plate 8 through the gas injection line 12, the flow rate is controlled by the secondary gas flow control system (11).

Hereinafter, the content of the present invention will be described in more detail with reference to Examples. However, these examples are only presented to understand the content of the present invention, and the scope of the present invention should not be construed as being limited to these embodiments.

<Example 1>

Sludge collected from the internal conveying pipe of the anaerobic digester at the sewage treatment plant at Daejeon was boiled for 15 minutes and injected into the fermenter. In order to maintain an environment suitable for hydrogen production, pH 5.3, the hydraulic residence time was 12 hours, the stirring speed was 100 rpm, the temperature was maintained at 35 ℃ and the effective volume of the reactor was 5 L, it was operated in a fully mixed manner. Sucrose was used as the substrate for the influent at a concentration of 20 g COD / L, NaHCO ₃ 2.5 g / L, KH ₂ PO ₄ 0.5 g / L, K ₂ HPO ₄ 0.5 g / L, NH ₄ Cl 1.5 g / L, MgCl ₂ · 6H ₂ O 0.1 g / L, CaCl ₂ · 2H ₂ O 0.01 g / L, MnCl ₂ · 6H ₂ O 0.015 g / L, Na ₂ MoO ₄ 4H ₂ O 0.01 g / L , FeCl ₂ · 4H ₂ O 0.02 g / L was added to form a culture.

2 shows the conversion to hydrogen for injected glucose over time. The operation was started for 20 days as a start-up period, and then further operated for 20 days without sparging, and the data at that time was used as a result of the control group. The sparging of each gas started after 40 days and allowed to acclimate for each partial pressure for 20 days, and run for 20 days at each sparging condition. As shown, it can be easily observed that the hydrogen conversion rate increases in the order of control, nitrogen and argon, carbon dioxide. In addition, the average hydrogen conversion rate, microbial concentration, glucose decomposition rate, the concentration of butyl acid in the by-products, the composition ratio of the total by-products, and the hydrogen partial pressure in the reaction tank in each condition are described in Table 1 below.

TABLE 1

Gas type Spazing Flow Rate (ml / min) Hydrogen conversion per injected glucose (mol H ₂ / mol glucose _added ) Hydrogen conversion per degraded glucose (mol H ₂ / mol glucose _consumed ) Concentration and Composition of Butyl Acid (mg COD / L,%) Hydrogen partial pressure (%) Control - 0.74 0.76 5,457 (36.0%) 63.2 nitrogen 100 0.87 0.91 6,248 (41.7%) 12.0 200 0.91 0.92 6,988 (44.8%) 7.0 300 0.93 0.95 7,400 (47.6%) 5.6 400 0.91 0.92 6,097 (39.7%) 3.9 argon 100 0.88 0.90 6,317 (42.0%) 12.0 200 0.92 0.94 7,011 (45.1%) 7.1 300 0.94 0.97 6,512 (42.3%) 5.5 400 0.88 0.91 6,327 (41.0%) 4.0 carbon dioxide 100 0.91 1.40 6,454 (67.6%) 11.9 200 1.15 1.65 7,450 (71.4%) 9.2 300 1.20 1.68 7,620 (72.4%) 6.7 400 1.20 1.57 8,185 (70.7%) 5.6

The amount of hydrogen produced was measured using a wet gas meter (15) and gas chromatography. The organic acid was analyzed by HPLC after filtering the effluent to 0.45 μm.

As can be seen from Table 1, when sparging with an external gas, the hydrogen conversion rate was higher than that of the control group with the increase in the concentration of butyl acid and the composition ratio according to the decrease in the partial pressure of hydrogen in the reactor. However, in the case of carbon dioxide, the hydrogen conversion rate and the concentration and composition ratio of butyl acid were higher than those of nitrogen and argon. In the case of carbon dioxide sparging, in addition to the effect of reducing hydrogen partial pressure due to external gas injection, hydrogen production was improved. This is because the production of hydrogen is improved. Although studies on carbon dioxide partial pressure during anaerobic fermentation are very poor, the literature reports that high carbon dioxide partial pressure inhibits the growth activity of microorganisms due to lowering of intracellular pH and damage to cell membranes. At high CO2 partial pressures, hydrogen is consumed and the activity of acetic acid or methane-producing microorganisms is inhibited (see, et al., Korean Journal of Radiological Hygiene, vol. 26 (2), 2000, p. 59-66, Dixon and Kell, J. Appl. Bacteriol., Vol. 67, 1989, p. 109-136). Although not shown in Table 1, in the case of the control and nitrogen sparging, the composition ratio of lactic acid and acetic acid was 20% or more in all cases, but in the case of carbon dioxide, the composition ratio was less than 10%. Therefore, the highest production of hydrogen when sparging with carbon dioxide is that high partial pressure of carbon dioxide hardly inhibits Clostridia, a major hydrogen-producing bacterium, and produces other lactic acid or consumes hydrogen to produce acetic acid. At the same time, it may be because it inhibited the microorganisms in competition in using Clostridia and the substrate. Optimum sparging conditions were sparging at 300 ml / min with carbon dioxide, the highest hydrogen conversion rate per injected or degraded glucose, with hydrogen conversion rates exceeding the previously reported values obtained from successive experiments. Higher value.

<Example 2>

The fermenter was operated without operating the stirrer 22 at the optimum sparging conditions (300 ml / min of carbon dioxide) derived from the results of Example 1, and the results are shown in Table 2. In other words, the second embodiment is to confirm the biological and physical effects of sparging by operating the fermenter without external physical agitation. Will be presented.

TABLE 2

Item unit value Hydrogen Conversion Per Glucose Infused (mol H ₂ / mol glucose _added ) 1.13 Hydrogen Conversion Per Glucose Decomposed (mol H ₂ / mol glucose _consumed ) 1.24 Butyl Acid Concentration and Composition Ratio (mg COD / L,%) 7,673 (57.5%) Hydrogen partial pressure (%) 6.15

As can be seen from Tables 1 and 2, even when the stirrer is not operated when sparging with carbon dioxide gas, the hydrogen conversion rate is higher than that of the control and sparging with nitrogen and argon gas. This allows economic reactor operation only through carbon dioxide gas sparging without additional physical agitation, confirming the possibility of operating in a real large-capacity reactor.

<Example 3>

Using the apparatus shown in FIG. 3, without recovering carbon dioxide externally, the biogas generated in the hydrogen fermenter itself is recovered under the optimum conditions derived in Examples 1 and 2 after recovering carbon dioxide through a gas separation membrane. Only sparging was performed without external physical agitation to produce hydrogen. As a gas separation membrane, hydrogen has been reported to be highly purified using a palladium membrane containing silver that adsorbs only hydrogen (Nielsen et al., Int. J. Hydrogen Energy, vol. 26, 2001, p. 547-550), and in addition, the process can be operated via a membrane called Mr. Hydrogen from REB Reseach & Consulting, which has a high degree of purification of more than 99.99%. In this example, carbon dioxide was recovered using "Mr hydrogen" and sparged at 300 ml / min, and the experimental results are shown in Table 3 below.

TABLE 3

Item unit value Hydrogen Conversion Per Glucose Infused (mol H ₂ / mol glucose _added ) 1.16 Hydrogen Conversion Per Glucose Decomposed (mol H ₂ / mol glucose _consumed ) 1.39 Butyl Acid Concentration and Composition Ratio (mg COD / L,%) 7,771 (62.7%) Hydrogen partial pressure (%) 6.20

It can be considered that additional cost is consumed depending on the installation of the membrane. However, in order to use the hydrogen generated in the anaerobic fermentation as energy, it is necessary to separate the hydrogen from the biogas. It is very economical in that it solves the hassle of separating.

The present invention provides a method for producing hydrogen with economical, stable and high efficiency as compared to the conventional anaerobic hydrogen fermentation method, in particular, it is possible to produce a large amount of hydrogen only through sparging without a separate mechanical stirring process.

In addition, the hydrogen fermentation apparatus according to the present invention to reduce the burden of additional costs due to the purchase of external gas by recovering carbon dioxide from the biogas (primary gas) produced in the fermentation tank and supplying it as a sparging gas (secondary gas), The hassle of purifying hydrogen can be removed.

1 is a schematic configuration diagram of a hydrogen fermentation process using external gas sparging.

2 is a graph showing the conversion rate of hydrogen according to the type and flow rate of the external gas.

Figure 3 is a schematic diagram of a hydrogen fermentation apparatus according to the present invention, by separating the hydrogen and carbon dioxide in the bio gas using a gas separation membrane of the hydrogen fermentation apparatus using hydrogen as an energy source, carbon dioxide is recovered as a sparging gas It is a schematic block diagram.

<Code Description of Main Parts of Drawing>

1: hydrogen fermentation tank 2: influent storage tank

3: effluent reservoir 4: potassium hydroxide reservoir

5: pH probe 6: pH controller

7: decompression pump 8: perforated plate

9,9 ', 9' ': Transfer pump 10,10': Level displacement gas generator

11: gas flow controller 12: gas injection line

13,13 ': gas sampling port 14: gas discharge line

15: wet gas meter 16: influent line

17: effluent line 18: potassium hydroxide inlet line

19: hydrogen recovery line 20: water vapor removal filter

21: gas separation membrane 22: agitator

23: gas cylinder

Claims (8)

A method for producing hydrogen by fermentation of hydrogen, wherein the organic wastewater in the fermenter is sparged with carbon dioxide gas to produce hydrogen gas from carbohydrates of the organic wastewater. The method for producing hydrogen according to claim 1, wherein anaerobic sludge is used as a seed germ. The method for producing hydrogen according to claim 2, wherein the anaerobic sludge is boiled at 90 to 100 DEG C for 10 to 20 minutes. The method of producing hydrogen according to claim 1, wherein the carbon dioxide gas is recovered from the biogas generated in the reactor. The method of producing hydrogen according to claim 1, wherein the sparging of carbon dioxide gas is performed at a flow rate of 250 to 350 ml / min. The method of claim 1, wherein the fermentation reaction is carried out at pH 5.3 ± 0.1, a temperature of 35 ± 1 ℃ hydrogen production method Inflow water supply unit for supplying organic wastewater into fermentation tank, outflow water discharge unit for discharging organic wastewater treated in fermentation tank, pH control unit for adjusting pH in fermentation tank, fermentation tank with perforated plate for sparging at bottom, In the hydrogen fermentation apparatus comprising a hydrogen recovery unit for recovering hydrogen gas, The hydrogen recovery unit gas discharge line 14 for discharging the primary gas generated in the fermentation tank, the primary gas generation meter 10 for collecting the primary gas and measure the amount of gas generated, hydrogen in the primary gas A gas separation membrane 21 for passing only gas, a pressure reducing pump 7 for reducing the pressure of the gas discharged from the primary gas generation meter to apply pressure to the gas separation membrane, and hydrogen gas separated from the gas separation membrane 21 The secondary gas injection line 12 collects the secondary gas, except for the hydrogen gas in the primary gas, and the hydrogen generation amount measuring instrument 10 'capable of measuring the amount of hydrogen collected and collected through the recovery line 19. Hydrogen fermentation apparatus, characterized in that it comprises a secondary gas flow control system 11 for supplying to the porous plate 8 through 8. The hydrogen fermentation apparatus according to claim 7, wherein a water vapor removal filter (20) for preventing the infiltration of water vapor in the gas separation membrane is further included in front of the inlet of the gas separation membrane.