CN102876723A - Method for producing hydrogen through intensified anaerobic fermentation - Google Patents

Abstract

The invention discloses a method for producing hydrogen through intensified anaerobic fermentation. The method comprises the following steps of: adding a culture medium, resazurin and a cetyl trimethyl ammonium bromide solution into a fermentation container, mixing uniformly, sterilizing, inoculating liquid obtained after cow dung is fermented, introducing sterile nitrogen into the fermentation container and an alkaline washing bottle which is connected with the fermentation container so as to displace the air, sealing a sterile nitrogen introduction port, performing shake culture at constant temperature, performing alkaline washing on gas produced by fermentation, and collecting to obtain the hydrogen. By adding cetyl trimethyl ammonium bromide into a fermentation substrate, the problems that the cost of the current hydrogen production by biological anaerobic fermentation is still high and the hydrogen production efficiency is low are solved, and the effects that the accumulated hydrogen yield is improved by 38 percent and the maximum hydrogen production rate is improved by 44 percent are successfully achieved. The method can be simply operated, and is low in cost and easy to implement.

Description

A kind of method of reinforced anaerobic ferment for hydrogen production

Technical field

The present invention relates to the microbial fermentation hydrogen preparation field, specifically a kind of method of reinforced anaerobic ferment for hydrogen production.

Background technology

Contradiction between ever-increasing energy demand and the exhaustion of fossil oil reserves is aggravated, and hydrogen is a very promising substitute energy as a kind of cleaning, efficient, reproducible energy carrier.Anaerobically fermenting hydrogen manufacturing is because it answers mild condition, equipment is simple and available raw material sources extensively are considered to a kind of hydrogen production process with extensive prospect in the method for numerous hydrogen makings.Yet hydrogen production through anaerobic fermentation is because feed stock conversion is low, and hydrogen-producing speed is low, can't contend with chemical method hydrogen manufacturing on the cost of hydrogen manufacturing at present.Improving feed stock conversion and hydrogen-producing speed is the problem that anaerobically fermenting hydrogen manufacturing demands urgently breaking through to reduce the hydrogen manufacturing cost.

Product H-H reaction in the anaerobically fermenting hydrogen manufacturing is reversible redox reaction

, H ₂Throughput rate is subjected to the impact of hydrogen-producing speed and hydrogen-absorption speed simultaneously.The interior hydrogen partial pressure of lower born of the same parents is conducive to produce H-H reaction to carry out to producing the hydrogen direction.In addition, the H that produces in the born of the same parents ₂To be discharged into liquid nutrient medium through cytolemma, and then be diffused into the gas phase of top.Thereby thereby the hydrogen partial pressure that the resistance that reduces hydrogen release is conducive to reduce in the born of the same parents is strengthened product hydrogen.Mandal becomes work hardening to produce hydrogen by the mode that reduces the hydrogen partial pressure of substratum top in the fermentation system.Consider cytolemma two phospholipid layer mobile caused aperture (being no more than 0.5-1.0nm) and hydrogen molecule diameter (near 0.3nm) quite, infer that speed that the hydrogen that produces in the born of the same parents discharges to extracellular fluid body substratum via cytolemma may be subject to the impact in cytolemma aperture.Therefore, we infer that improving permeability of cell membrane can reduce hydrogen by the resistance that discharges in the born of the same parents outside born of the same parents, thereby reduce H in the cell ₂Pressure, and finally improve hydrogen-producing speed.

Summary of the invention

The object of the invention is to screen a kind of membrane passage that can effectively improve and do not affect again a kind of reagent that produces the hydrogen microbial growth and metabolism, explore the concentration conditions as the anaerobically fermenting hydrogen production additive of this reagent, the final reinforcement that realizes accumulative total hydrogen output and hydrogen-producing speed.

The present invention solves the problems of the technologies described above the technical scheme of employing to be: a kind of method of reinforced anaerobic ferment for hydrogen production, comprise following steps: according to volume ratio, the substratum that in fermenting container, adds 100 parts, and according to the ratio adding resazurin that adds the 1mg resazurin in every liter of substratum, the cetyl trimethylammonium bromide solution that to add 5 parts of mass concentrations be 0.2 ~ 0.6g/L again, after mixing, 15min sterilizes under 121 ℃ condition, then inoculate 5 parts of liquid after taking from cattle manure, in fermenting container and the alkali cleaning bottle that is attached thereto, pass into aseptic nitrogen until the color of fermentation system is become colorless by pink colour again, then sealed, sterile nitrogen passes into mouth, at 37 ℃ of constant temperature, concussion is cultivated under the condition of 155r/min, the gas that fermentation produces enters by breather line and is equipped with in the alkali cleaning bottle that concentration is 2 ~ 4mol/L sodium hydroxide solution, then collects the gas that overflows and be the hydrogen that fermentation produces from the alkali cleaning bottle;

Consisting of of described substratum: contain the wood sugar of 10g, the peptone of 5g, the dipotassium hydrogen phosphate of 14g, the ammonium sulfate of 2g, the potassium primary phosphate of 6 g and the MgSO of 0.2 g in every liter of substratum ₄7H ₂O, all the other are distilled water, the substratum that the prepares 15min that sterilizes under 121 ℃ condition before use.

Among the present invention, the effect of described adding resazurin is for the anaerobism index of observing substratum.

Among the present invention, the liquid behind the described cattle manure is actually a kind of mixed bacterium liquid.

In substratum, add certain density cetyl trimethylammonium bromide, i.e. CTAB, the growth metabolism of mixed bacterium is not subject to obvious restraining effect, the membrane passage of mixed bacterium be improved significantly, CTAB is as follows on the impact experiment of microorganism:

One, the impact of CTAB cell membrane permeability

Mixed bacterium: take from the tank for sewage gas of cattle manure, its bacterial cell density is 1.8 ~ 2.2;

Substratum preparation: contain 10g wood sugar, 5g peptone, 14g dipotassium hydrogen phosphate, 2 g (NH4) in every liter of substratum ₂SO ₄, 6 g potassium primary phosphates and 0.2 g MgSO ₄7H ₂O, all the other are distilled water, the substratum that the prepares 15min that sterilizes under 121 ℃ condition before use;

Cell suspending liquid preparation: mixed bacterial anaerobism in substratum is cultivated 24 h, and then the centrifuging and taking precipitation is that the potassium phosphate buffer of 7,100 mmoles is clean with pH, adds an amount of damping fluid (optical density value OD under 600 nm ₆₀₀Equal 3.31) preserve.

The impact of CTAB cell membrane permeability: the CTAB solution of preparing respectively 0,0.1,0.2,0.3,0.4,0.6,0.8,1.2 g/L; Get in the serum bottle of 4mL cell suspending liquid and 0.2 mL CTAB solution adding 7mL, keep 15min under 37 ℃ of conditions, then the centrifuging and taking supernatant is measured its absorbance (A under 280nm ₂₈₀) with estimation protein seepage discharge and membrane passage.

Be the action time of analyzing CTAB of the impact on the albumen seepage discharge, be extended for 90min and 135min repeats above-mentioned experiment the action time in serum bottle with cell suspending liquid and CTAB solution.

Under the wavelength condition of 280nm, there is absorption that detection is impacted for getting rid of CTAB, do the control experiment that does not contain cell suspending liquid: damping fluid and the 0.2mL concentration of getting a serum bottle adding 4mL are respectively 0,0.1,0.2,0.3,0.4,0.6,0.8 the CTAB solution of 1.2 g/L keeps 135 min to detect its absorbancy.

Experimental result is as shown in Figure 1: without absorbing, experiment detects A to CTAB under the 280nm condition ₂₈₀Be the absorbancy of oozing out albumen in the born of the same parents; When be 15min the action time of CTAB and cell along with CTAB concentration increases A ₂₈₀Increase, show that CTAB can promote oozing out of intracellular protein class material; The action time that prolongs CTAB and cell is little on the impact of cell seepage discharge; Thereby, draw the increase that CTAB can promote mixed bacterium cell permeability.

Two, CTAB is on the impact of microorganism growth

The biomass of fermentation terminal uses the terminal fermented liquid at the optical density value (OD of 600nm ₆₀₀) characterize.

CTAB is on the impact of microorganism growth as shown in Figure 2, and is as shown in the table: the existence of CTAB so that microorganism in the front 12h poor growth of fermentation, but microorganism growth is quick after the 12h, biomass is suitable with the biomass that does not add CTAB when the fermentation terminal.

Beneficial effect: the present invention is that a brand-new thinking is started in the fermentative hydrogen production field, the principle of hydrogen partial pressure in reducing the cell born of the same parents, filter out a kind of can effectively increase membrane passage again to microorganism growth without the Surfactant CTAB that obviously suppresses as additive, the cost that has overcome present bio anaerobic ferment for hydrogen production is high, the problem that hydrogen generation efficiency is low, success realizes that the accumulative total hydrogen output improves 38%, and maximum hydrogen-producing speed improves 44% effect.The present invention is simple to operate, and is with low cost, is easy to realize.

Description of drawings

Fig. 1 is the impact of the CTAB cell membrane permeability of different concns;

Fig. 2 is that the CTAB of different concns is on the impact of microorganism growth;

Fig. 3 is the used experimental installation of embodiment;

Fig. 4 is the experimental result comparison diagram of embodiment 1;

Fig. 5 is the experimental result comparison diagram of embodiment 2;

Fig. 6 is the experimental result comparison diagram of embodiment 3.

Embodiment

The present invention is further elaborated below in conjunction with specific embodiment.

Embodiment 1

In the 500mL Erlenmeyer flask as batch reactor, the substratum that adds therein 100mL, 0.1mg resazurin, adding the 5mL mass concentration is the cetyl trimethylammonium bromide solution of 0.2g/L again, after mixing, 15min sterilizes under 121 ℃ condition, then inoculate the liquid after 5mL takes from cattle manure, in Erlenmeyer flask and the alkali cleaning bottle that is attached thereto, pass into aseptic nitrogen until the color of fermentation system is become colorless (aeration time is about 10min) by pink colour again, then sealed, sterile nitrogen passes into mouth, at 37 ℃ of constant temperature, the shaking flask concussion is cultivated under the condition of 155r/min, the gas that fermentation produces enters by breather line and is equipped with in the alkali cleaning bottle that concentration is the 2mol/L sodium hydroxide solution, then collects the gas that overflows and be the hydrogen that fermentation produces from the alkali cleaning bottle;

Consisting of of described substratum: contain the wood sugar of 10g, the peptone of 5g, the dipotassium hydrogen phosphate of 14g, the ammonium sulfate of 2g, the potassium primary phosphate of 6 g and the MgSO of 0.2 g in every liter of substratum ₄7H ₂O, all the other are distilled water, the substratum that the prepares 15min that sterilizes under 121 ℃ condition before use;

The described liquid of taking from behind the cattle manure, its bacterial cell density is 1.8 ~ 2.2.

Experimental installation as shown in Figure 3.

Adopt the gas chromatographic detection hydrogen content, actual conditions is: Porapak Q stainless stee l packed column, 80 ℃ of column temperatures, carrier gas is nitrogen, and flow velocity is 30 mL/min, and the Sample Room temperature is 80 ℃, sensing chamber's thermal conductivity detector (TCD), 120 ℃ of sensing chamber's temperature, bridge electric current 150 mA.

The method of calculation of hydrogen-producing speed: the Gompertz equation of correction can be described in the batch experiment over time rule of microorganism growth preferably, and its expression formula is:

(1)

In the formula, H is the accumulation hydrogen output in the t time, mL; P is the cumulative maximum hydrogen output, mL; Rm is maximum hydrogen-producing speed, mL/h; λ is product hydrogen dead time, h.

With the available P of Gompertz equation (formula 1) match, Rm and three parameters of λ of revising, then use the hydrogen-producing speed in formula (2) the calculating batch experiment.

（2）

Calculate experimental result and do contrast with the situation that does not add CTAB, the result as shown in Figure 4.

Drawn by accompanying drawing 4, add the CTAB of 0.2g/L than the situation that does not add CTAB, hydrogen-producing speed has improved 10.30%, and maximum hydrogen-producing speed has improved 17.87%, and the accumulative total hydrogen output has improved 6.82%; Simultaneously, although making, the interpolation of CTAB produces hydrogen prolongation dead time, to the OD of terminal fermentation ₆₀₀With pH without considerable influence, CTAB is to microbial growth and produce the hydrogen metabolism and have no significant effect.

Embodiment 2

Used experimental installation, experiment condition and experimental implementation are all identical with embodiment 1, and the concentration of the CTAB of adding is 0.4g/L, and the concentration of sodium hydroxide solution is 3mol/L in the buck bottle.

Adopt the gas chromatographic detection hydrogen content, and do contrast with the situation that does not add CTAB, the result as shown in Figure 5.

Drawn by accompanying drawing 5, add the CTAB of 0.4g/L than the situation that does not add CTAB, hydrogen-producing speed has improved 15.26%, and maximum hydrogen-producing speed has improved 31.10%, and the accumulative total hydrogen output has improved 22.73%; Simultaneously, although making, the interpolation of CTAB produces hydrogen prolongation dead time, to the OD of terminal fermentation ₆₀₀With pH without considerable influence, CTAB is to microbial growth and produce the hydrogen metabolism and have no significant effect.

Embodiment 3

Used experimental installation, experiment condition and experimental implementation are all identical with embodiment 1, and the concentration of the CTAB of adding is 0.6g/L, and the concentration of sodium hydroxide solution is 4mol/L in the buck bottle.

Adopt the gas chromatographic detection hydrogen content, and do contrast with the situation that does not add CTAB, the result as shown in Figure 6.

Drawn by accompanying drawing 6, add the CTAB of 0.6g/L than the situation that does not add CTAB, hydrogen-producing speed has improved 18.70%, and maximum hydrogen-producing speed has improved 43.91%, and the accumulative total hydrogen output has improved 38.18%; Simultaneously, although making, the interpolation of CTAB produces hydrogen prolongation dead time, to the OD of terminal fermentation ₆₀₀With pH without considerable influence, CTAB is to microbial growth and produce the hydrogen metabolism and have no significant effect.

Claims (1)

1. the method for a reinforced anaerobic ferment for hydrogen production, it is characterized in that, comprise following steps: according to volume ratio, the substratum that in fermenting container, adds 100 parts, and according to the ratio adding resazurin that adds the 1mg resazurin in every liter of substratum, the cetyl trimethylammonium bromide solution that to add 5 parts of mass concentrations be 0.2 ~ 0.6g/L again, after mixing, 15min sterilizes under 121 ℃ condition, then inoculate 5 parts of liquid after taking from cattle manure, in fermenting container and the alkali cleaning bottle that is attached thereto, pass into aseptic nitrogen until the color of fermentation system is become colorless by pink colour again, then sealed, sterile nitrogen passes into mouth, at 37 ℃ of constant temperature, concussion is cultivated under the condition of 155r/min, the gas that fermentation produces enters by breather line and is equipped with in the alkali cleaning bottle that concentration is 2 ~ 4mol/L sodium hydroxide solution, then collects the gas that overflows and be the hydrogen that fermentation produces from the alkali cleaning bottle;

Consisting of of described substratum: contain the wood sugar of 10g, the peptone of 5g, the dipotassium hydrogen phosphate of 14g, the ammonium sulfate of 2g, the potassium primary phosphate of 6 g and the MgSO of 0.2 g in every liter of substratum ₄7H ₂O, all the other are distilled water, the substratum that the prepares 15min that sterilizes under 121 ℃ condition before use.

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