CN106754259A - A kind of synthesis gas that ferments produces the system and its processing method of alcohols - Google Patents

Abstract

The invention provides a system for fermenting synthesis gas to produce alcohols and a treatment method thereof. The system includes a bubble-free gas supply membrane module, a bioreactor and a pervaporation membrane module, wherein the bubble-free gas supply membrane module is placed in a biological reaction In the bioreactor or placed outside the bioreactor, the air inlet of the bubble-free gas supply membrane module is connected to the syngas, the fermentation liquid outlet of the bioreactor is connected to the feed port of the pervaporation membrane module, and the retentate outlet of the pervaporation membrane module is It is connected with the material inlet of the bioreactor. The system and method of the present invention adopt double-end or single-end gas supply membrane technology without bubbles, and combine fermentation-pervaporation separation coupling fermentation technology to improve the gas-liquid transmission rate, gas utilization efficiency, The concentration of microbial cells and product concentration reduces the material consumption of cultured cells, increases the cell density in the fermentation process, and improves fermentation efficiency and product concentration.

Description

A system for fermenting synthesis gas to produce alcohols and its treatment method

technical field

The invention belongs to the technical field of fermentation engineering, and in particular relates to a system for fermenting synthesis gas to produce alcohols and a processing method thereof.

Background technique

Syngas is a kind of mixed gas with CO, CO ₂ and H ₂ as the main components, mainly from energy-intensive industries such as synthetic ammonia industry, petroleum refining industry, steel mills and wood pulp and paper mills. China's annual industrial emissions exceed 600 10,000 tons of CO and 4 million tons of H ₂ . In recent years, the comprehensive utilization of syngas by biological methods has attracted great attention, especially the technology of converting syngas into ethanol and butanol through microbial anaerobic fermentation. However, the slow fermentation reaction rate and low product concentration limit the commercial operation of this technology. There are three main reasons for the slower reaction rate and lower product concentration, namely lower gas-liquid transmission rate, lower gas utilization efficiency and lower microbial cell concentration.

In order to solve the above problems, researchers have conducted a series of studies and developed new fermentation devices or technologies:

(1) CN 103374592A discloses a method for producing ethanol by fermentation of a gas-phase substrate. The bacteria in the fermentation broth are separated by centrifugation, hollow fiber filtration, precipitation or ultrafiltration, and the separated bacteria are returned to the bioreactor for reuse; The final organic solution is rectified, and part of the remaining raffinate is returned to the bioreactor, and the rest is discharged as fermentation waste liquid; CO ₂ in the fermentation tail gas is separated and enriched in CO and/or H ₂ , and then the enriched CO and/or H ₂ into the bioreactor. Although this method partially improves the gas-phase substrate conversion rate and increases the concentration of microbial cells, it does not solve the problems of low gas-liquid transmission rate and low product concentration;

(2) CN 101768540A discloses a device for producing organic acids and alcohols from syngas, which combines the advantages of stirred reactors and airlift reactors, that is, the reactor integrates stirring, gas circulation Flow tube and gas distributor, etc. Although the device has enhanced the gas-liquid mass transfer effect and gas utilization rate, it still has not solved the problem of low product and microbial cell concentration;

(3) CN 101831382A discloses a bubble-free gas supply-solid-liquid separation integrated membrane bioreactor using insoluble gas as the fermentation raw material, wherein the bubble-free gas supply is a dead-end hollow fiber membrane module, that is, the gas can only be produced by One end of the hollow fiber membrane enters and cannot flow out from the other end, and the gas entering the membrane cavity can only diffuse and pass out from the membrane pores; the solid-liquid separation membrane module is equipped with an ultrafiltration membrane or a microfiltration membrane, which allows water, small molecule organic acids and Substances such as alcohol pass through, but particulate matter such as fermented cells cannot pass through, so that fermented cells remain in the reactor, and fermentation products can be discharged from the reactor; air-supply hollow fiber membrane modules and solid-liquid separation membrane modules are submerged in the reactor below the liquid level of the solution in the vessel. This technology improves the gas utilization rate, fermentation reaction rate and cell concentration, but its fermentation product concentration is low, which does not solve the problem of low fermentation product concentration.

The concentration of ethanol or butanol synthesized by fermentation of synthetic gas is too low, and the traditional distillation technology consumes a lot of energy. For example: when the butanol concentration in the fermentation broth is 0.5%, the distillation energy consumption is 79.5MJ/kg butanol; when the butanol concentration is increased to 1%, the distillation energy consumption is reduced to 26.8MJ/kg butanol; when butanol The concentration is 11%, and the distillation energy consumption is 17MJ/kg butanol. Therefore, increasing the concentration of ethanol or butanol in the feed liquid before distillation is one of the effective measures to reduce energy consumption. In addition, there is a phenomenon of product inhibition during ethanol and butanol fermentation, that is, the accumulation of ethanol mass concentration exceeding 50g/L in the ethanol fermentation process will inhibit the growth of yeast cells, and the cell activity will be reduced when the butanol concentration reaches 7-13g/L. lose half. Therefore, the concentration of ethanol in the fermentation broth is generally less than 50g/L, and the concentration of butanol is less than 13g/L. Such low product concentrations are difficult to separate and purify by distillation, making this technology difficult for industrial production. Therefore, reducing the concentration of ethanol or butanol in the fermentation process is also one of the measures to improve the fermentation of syngas.

Compared with other technologies for recovering ethanol or butanol, pervaporation technology uses membrane materials to dissolve and diffuse components in the separated solution to achieve separation. Its characteristics are:

(i) Typical energy-saving technology (low energy consumption, generally 1/2 to 3/4 energy saving than azeotropic distillation). It is reported that the use of gas stripping technology, extraction, adsorption and pervaporation membrane technology to separate and concentrate butanol from fermentation broth, and find that the energy consumption of these methods is 21MJ/Kg (butanol), 14MJ/Kg (butanol) respectively. Alcohol), 33MJ/Kg (butanol) and 9MJ/Kg (butanol), the energy consumption of pervaporation membrane separation technology is the lowest;

(ii) Typical clean production technology, no other components are introduced into the process, and the products and the environment will not be polluted;

(iii) Typical convenient amplification and coupling techniques. It is especially suitable for the separation of near-boiling and azeotropic mixtures that are difficult or impossible to separate by ordinary rectification. It is more advantageous for the separation of materials and liquids where the concentration of organic solvents in water is less than 5%.

However, in the prior art, there is no technology combining syngas fermentation and pervaporation at the same time to solve the above-mentioned problems in the prior art that the concentration of alcohols in the fermentation broth is too high and the concentration of fermentation products is too low. Therefore, there is an urgent need to seek a technical solution to simultaneously solve the problems of excessively high concentration of alcohols and low concentration of fermentation products in the fermentation broth.

Contents of the invention

Aiming at the problems in the prior art that the concentration of alcohols in the fermentation broth is too high and the concentration of fermentation products is too low, the present invention provides a system for producing alcohols by fermenting synthesis gas and a treatment method thereof. The system and method of the present invention adopt double-end or single-end gas supply membrane technology without bubbles, combined with fermentation-pervaporation separation coupling fermentation technology, to improve the gas-liquid transmission rate, gas utilization efficiency, The concentration of microbial cells and product concentration reduces the material consumption of cultured cells, increases the cell density in the fermentation process, and improves fermentation efficiency and product concentration.

For reaching this purpose, the present invention adopts following technical scheme:

In a first aspect, the present invention provides a system for fermenting syngas to produce alcohols, said system comprising a bubble-free gas supply membrane module, a bioreactor and a pervaporation membrane module, wherein the bubble-free gas supply membrane module is placed in a biological reaction In the bioreactor or placed outside the bioreactor, the air inlet of the bubble-free gas supply membrane module is connected to the syngas, the fermentation liquid outlet of the bioreactor is connected to the feed port of the pervaporation membrane module, and the retentate outlet of the pervaporation membrane module is It is connected with the material inlet of the bioreactor.

In the present invention, the non-bubble gas supply device can realize the transmission and supply of gas without forming bubbles, avoiding the loss of raw material gas escaping from the main solution in the form of bubbles, thereby improving the gas utilization efficiency.

The following are preferred technical solutions of the present invention, but not as limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

As a preferred technical solution of the present invention, when the bubble-free gas supply membrane module is placed in the bioreactor, the bubble-free gas supply membrane module is placed below the liquid level of the fermentation liquid in the bioreactor, and directly connected with the fermentation liquid in the bioreactor. touch.

Preferably, when the bubble-free gas supply membrane module is placed outside the bioreactor, the fermentation liquid in the bioreactor is connected to the liquid inlet of the bubble-free gas supply membrane module through a delivery pump, and the liquid outlet of the bubble-free gas supply membrane module Connected to the feed port of the bioreactor. That is, the fermentation broth in the bioreactor is pumped into the bubble-free air supply membrane module through the delivery pump for treatment, and the treated fermentation broth is returned from the bubble-free air supply membrane module to the bioreactor for fermentation reaction.

As a preferred technical solution of the present invention, the gas partial pressure in the bubble-free gas supply membrane module is lower than the bubble pressure.

Preferably, any one or a combination of at least two of hollow fiber membrane modules, tubular membrane modules or flat membrane modules is built into the bubble-free air supply membrane module. Typical but non-limiting examples of the combination include: hollow Combinations of fiber membrane modules and tubular membrane modules, combinations of tubular membrane modules and flat membrane modules, combinations of hollow fiber membrane modules, tubular membrane modules and flat membrane modules, etc., are preferably hollow fiber membrane modules.

Preferably, the hollow fiber membrane module is made of any one or at least two materials of polyethylene, polypropylene, polyacrylonitrile, polysulfone, polyethersulfone, polyvinylidene fluoride or polytetrafluoroethylene Microporous gas-permeable films, typical but non-limiting examples of such combinations are: combinations of polyethylene and polypropylene, combinations of polyvinylidene fluoride and polytetrafluoroethylene, combinations of polypropylene, polyacrylonitrile and polysulfone, polysulfone , the combination of polyethersulfone and polyvinylidene fluoride, the combination of polyethylene, polypropylene and polyvinylidene fluoride, the combination of polyethylene, polypropylene, polyvinylidene fluoride and polytetrafluoroethylene, etc.

Wherein, the microporous hydrophobic and breathable film is a porous film with a pore diameter between 5.0 nm and 1.0 mm.

Preferably, the outer diameter of the hollow fiber membrane is 0.02 mm to 4.0 mm, such as 0.02 mm, 0.05 mm, 0.1 mm, 0.5 mm, 1.0 mm, 2.0 mm, 3.0 mm or 4.0 mm, etc., but not limited to the listed The numerical value, other unlisted numerical values within this numerical range are also applicable; the wall thickness is 0.01mm to 0.7mm, such as 0.01mm, 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm or 0.7mm etc., but not limited to the listed values, other unlisted values within this range are also applicable; the pore diameter is 0.04 μm to 0.8 μm, such as 0.04 μm, 0.06 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm or 0.8 μm, etc., but not limited to the listed values, other unlisted values within this range are also applicable.

For hollow fiber membranes, the realization of bubble-free gas supply requires that the gas partial pressure in the cavity of the hollow fiber membrane must be lower than the bubble pressure, and the bubble pressure is related to the pore size of the membrane. For example: when the pore diameter of the hollow fiber is 0.22 μm, the foaming pressure is 0.35 MPa ~ 0.40 MPa; when the pore diameter of the hollow fiber is 0.8 μm, the foaming pressure is 0.11 MPa; MPa. It can be seen that the pore size of the hollow fiber membrane needs to be controlled within a certain range.

At the same time, there is a certain pressure drop when the gas flows in the hollow fiber membrane, and the gas transmission effect can only be guaranteed if the gas in the membrane cavity maintains an appropriate pressure. Therefore, when the synthesis gas is fed in below the bubble point, there is a certain requirement for the length of the hollow fiber membrane, that is, the length of the hollow fiber membrane cannot be too long, otherwise the too long part will not be able to transport the gas and waste raw materials.

Preferably, the gas partial pressure in the hollow fiber membrane is less than 0.5MPa, such as 0.45MPa, 0.4MPa, 0.35MPa, 0.3MPa, 0.25MPa, 0.2MPa, 0.15MPa or 0.1MPa and lower gas partial pressure, but It is not limited to the listed values, and other unlisted values within the range of values are also applicable.

Preferably, when the bubble-free gas supply membrane module is placed in a bioreactor, the built-in hollow fiber membrane module is a curtain type hollow fiber membrane module and/or a cartridge type hollow fiber membrane module.

Preferably, when the bubble-free gas supply membrane module is placed outside the bioreactor, the hollow fiber membrane module inside it is a cartridge type hollow fiber membrane module.

As a preferred technical solution of the present invention, the bubble-free air-supply membrane module is arranged individually or at least two in parallel, wherein the number of parallel connections can be 2, 3, 4, 5, 6 or 7, etc. And more parallel connections, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the bubble-free air-supply membrane module has single-end air intake or two-end air intake.

Preferably, the pervaporation membrane module is provided with a pervaporation preferential alcohol permeable membrane, that is, the pervaporation preferential alcohol permeable membrane can permeate alcohols and retain other substances in the original solution to form a retentate.

Preferably, the pervaporation preferential alcohol permeable membrane is prepared from any one or at least two of organic membranes, inorganic membranes or organic-inorganic hybrid membranes. Typical but non-limiting examples of the combination include: organic membranes and Combination of inorganic membrane, combination of inorganic membrane and organic-inorganic hybrid membrane, combination of organic membrane, inorganic membrane and organic-inorganic hybrid membrane, etc. Its preparation method is an existing method in the prior art, and will not be repeated here.

Preferably, the material of the organic membrane is any one or a combination of at least two of silicone rubber, polytrimethylsilane, polypropylene or polyvinylidene fluoride. Typical but non-limiting examples of the combination are: silicone rubber Combination with polytrimethylsilpropane, combination of polytrimethylsilpropane and polypropylene, combination of polypropylene and polyvinylidene fluoride, combination of silicone rubber, polytrimethylsilpropane and polypropylene, silicone rubber, Combinations of polytrimethylsilane, polypropylene and polyvinylidene fluoride, etc.

Preferably, the material of the inorganic film is Silicalite-1 and/or ZSM-5.

Preferably, the material of the organic-inorganic hybrid membrane is any one or a combination of at least two of PDMS-Silicalite-1, PDMS-ZSM-5 or PTMSP-Silicalite-1, the combination is typical but not limiting Examples are: combination of PDMS-Silicalite-1 and PDMS-ZSM-5, combination of PDMS-ZSM-5 and PTMSP-Silicalite-1, combination of PDMS-Silicalite-1, PDMS-ZSM-5 and PTMSP-Silicalite-1 Wait.

Preferably, the pervaporation membrane module is in the form of any one or a combination of at least two of coiled membrane modules, tubular membrane modules, plate-and-frame membrane modules or hollow fiber membrane modules, which are typical but not Limiting examples are: the combination of wound membrane modules and tubular membrane modules, the combination of tubular membrane modules and plate and frame membrane modules, the combination of plate and frame membrane modules and hollow fiber membrane modules, the combination of wound membrane modules, tube membrane modules, The combination of membrane modules and plate-and-frame membrane modules, the combination of roll-type membrane modules, tubular membrane modules, plate-and-frame membrane modules and hollow fiber membranes, etc.

Preferably, the pervaporation membrane modules are arranged singly or at least two in series or in parallel.

Preferably, the series or parallel connection of the pervaporation membrane modules is through the permeate side of the pervaporation membrane modules through the pipeline. The permeate side of each series or parallel pervaporation membrane module is connected to the main pipeline of the vacuum pump through a pipeline.

In the present invention, a vacuum pump is used to extract a vacuum on the permeation side of the pervaporation membrane module, and normal pressure is maintained on the material side, so that there is a driving force between the two sides of the membrane, so that the ethanol vapor passes through the separation membrane and passes through the condenser on the permeation side of the membrane. Collect to obtain concentrated alcoholic liquid.

Preferably, the bioreactor is provided with a tail gas outlet and a feeding port, wherein the tail gas outlet is used to discharge the gas escaped from the fermentation broth.

Preferably, a power delivery pump is provided between the fermentation liquid outlet of the bioreactor and the feed inlet of the pervaporation membrane module to pump out the fermentation liquid in the bioreactor.

In a second aspect, the present invention provides a treatment method for the above-mentioned system for fermenting synthesis gas to produce alcohols, the method comprising the following steps:

(a) After the synthesis gas is processed by the bubble-free gas supply membrane module, it is sent to the bioreactor for fermentation treatment to synthesize alcohols;

(b) sending the alcohols synthesized in step (a) into the pervaporation membrane module for pervaporation, the obtained alcohol vapor is condensed to obtain alcohol concentrated liquid, and the retained liquid obtained by pervaporation is returned for fermentation treatment.

As a preferred technical solution of the present invention, the synthesis gas in step (a) contains CO and/or H ₂ .

Preferably, the alcohols synthesized in step (a) are ethanol and/or butanol.

Preferably, the concentration of ethanol in the fermentation broth built into the bioreactor in step (a) is 0.5g/L to 50g/L, such as 0.5g/L, 1g/L, 5g/L, 10g/L, 15g/L L, 20g/L, 25g/L, 30g/L, 35g/L, 40g/L, 45g/L or 50g/L, etc., but not limited to the listed values, other unlisted values within this range are the same Be applicable.

Preferably, the concentration of butanol in the fermentation broth built into the bioreactor in step (a) is 0.5g/L to 20g/L, such as 0.5g/L, 1g/L, 3g/L, 5g/L, 7g /L, 10g/L, 13g/L, 15g/L, 17g/L or 20g/L, etc., but not limited to the listed values, other unlisted values within this range are also applicable.

Preferably, the microorganism used in the fermentation treatment in step (a) is any one of Clostridium ljungdahlii, Clostridium carboxidivorans or Butyribacterium methylotrophicum, but is not limited to the above-mentioned three strains, and also includes any mutations carried out on the basis of the above-mentioned strains strain.

In the present invention, the microorganisms used in the fermentation treatment are Clostridium ljungdahlii ATCC 49587, Clostridium carboxidivorans P7 (ATCCBAA-624) or Butyribacterium methylotrophicum DSM3468 purchased from American Standard Biological Collection Center and DSM Group.

As a preferred technical solution of the present invention, the fermentation treatment in step (a) is a continuous fermentation process or a batch-batch fermentation process.

Preferably, medium components without carbon source are supplemented during the continuous fermentation process.

Preferably, the fermentation temperature of the fermentation treatment in step (a) is 30°C to 50°C, such as 30°C, 33°C, 35°C, 37°C, 40°C, 43°C, 45°C, 47°C or 50°C, etc. , but not limited to the listed values, other unlisted values within this range are also applicable.

As a preferred technical solution of the present invention, the temperature of the pervaporation treatment in step (b) is 30°C to 50°C, such as 30°C, 33°C, 35°C, 37°C, 40°C, 43°C, 45°C, 47°C °C or 50 °C, etc., but not limited to the listed values, and other unlisted values within this range are also applicable.

Preferably, the concentration of ethanol in the alcohol concentrate obtained by condensation in step (b) is 10g/L-500g/L, such as 10g/L, 50g/L, 100g/L, 150g/L, 200g/L, 250g/L, 300g/L, 350g/L, 400g/L, 450g/L or 500g/L, etc., but not limited to the listed values, other unlisted values within this range are also applicable.

Preferably, the concentration of butanol in the alcohol concentrate obtained by condensation in step (b) is 10g/L-200g/L, such as 10g/L, 30g/L, 50g/L, 70g/L, 100g/L , 130g/L, 150g/L, 170g/L or 200g/L, etc., but not limited to the listed values, other unlisted values within this range are also applicable.

The concentration of above-mentioned ethanol and butanol is determined by the concentration of ethanol and butanol in the fermented liquid before condensation, if the content of ethanol and/or butanol in the fermented liquid before condensation is much, then concentration can also obtain concentrated liquid.

As a preferred technical solution of the present invention, the method also includes step (c):

Escape gas during the fermentation process described in step (a), separate the escaping gas, and separate alcohols and water from the escaping gas to obtain a fermentation tail gas, and the gained fermentation tail gas is separated from _CO After being separated from the step ( a) The synthesis gas is mixed and processed by the bubble-free gas supply membrane module.

Preferably, the method for separating alcohols and water from the escaping gas is any one or a combination of at least two of condensation, membrane separation or solvent absorption, and the typical but non-limiting examples of the combination are : Combination of condensation method and membrane separation method, combination of membrane separation method and solvent absorption method, combination of condensation method, membrane separation method and solvent absorption method, etc.

Preferably, the method for separating CO ₂ from the fermentation tail gas is an adsorption method and/or a membrane separation method.

As a preferred technical solution of the present invention, the method comprises the following steps:

(a) After the synthesis gas containing _CO and/or H is processed by a bubble-free gas supply membrane module, it is sent to a bioreactor for fermentation treatment to synthesize ethanol and/or butanol;

Among them, the concentration of ethanol in the fermentation broth built in the bioreactor is 0.5g/L～50g/L; the concentration of butanol in the fermentation broth built in the bioreactor is 0.5g/L～20g/L;

The microorganism used in the fermentation treatment is any one of Clostridium ljungdahlii, Clostridium carboxidivorans or Butyribacterium methylotrophicum;

(b) sending the alcohols synthesized in step (a) into the pervaporation membrane module for pervaporation, the obtained alcohol vapor is condensed to obtain an alcohol concentrate, and the retentate obtained by the pervaporation is returned for fermentation treatment;

The concentration of ethanol in the alcohol concentrate obtained by the condensation is 10g/L～500g/L;

The concentration of butanol in the alcohols concentrate obtained by the condensation is 10g/L～200g/L;

(c) Escape gas during the fermentation process described in step (a), separate the escaping gas, separate alcohols and water from the escaping gas, and obtain fermentation tail gas, and separate _CO from the obtained fermentation tail gas It is mixed with the synthesis gas in step (a) and processed by a bubble-free gas supply membrane module.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The bubble-free air supply membrane module adopted in the system of the present invention adopts single-end air intake or two-end air intake, which improves the membrane area in the air supply process, and especially can reduce the required air supply of large reactors units, reducing production costs;

(2) The use of pervaporation membrane modules in the system of the present invention can immediately remove the alcohols in the fermentation process from the fermentation system, reduce the concentration of alcohols in the bioreactor, and reduce the concentration of ethanol in the reactor to below 50g/L, The concentration of butanol is reduced to below 20g/L to reduce the inhibitory effect on the product;

(2) The use of pervaporation membrane modules in the system of the present invention allows the intercepted cells to flow back to the reactor to continue to participate in the fermentation reaction, increasing the cell density of the fermentation system; at the same time, it realizes the recycling of cells and reduces the fermentation early stage. The material consumption and culture time of cultured cells improve the substrate conversion rate of products;

(3) The system of the present invention increases the reaction rate and the product concentration of syngas fermentation to produce ethanol or butanol, so that the final ethanol concentration can reach 10g/L～500g/L, and the concentration of butanol is 10g/L ~200g/L.

Description of drawings

Fig. 1 is a schematic structural diagram of a system for fermenting synthesis gas to produce alcohols described in Example 1 of the present invention;

Fig. 2 is a schematic structural diagram of a system for fermenting synthesis gas to produce alcohols described in Example 3 of the present invention;

Among them, 1-bubble-free gas supply membrane module, 2-bioreactor, 3-pervaporation membrane module.

detailed description

In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the present invention will be further described in detail below. However, the following embodiments are only simple examples of the present invention, and do not represent or limit the protection scope of the present invention, and the protection scope of the present invention shall be determined by the claims.

Part of the specific embodiments of the present invention provides a system for fermenting syngas to produce alcohols, the system includes a bubble-free gas supply membrane module 1, a bioreactor 2 and a pervaporation membrane module 3, wherein the bubble-free gas supply membrane module 1 Placed in bioreactor 2 or placed outside bioreactor 2, the air inlet of bubble-free gas supply membrane module 1 is connected to syngas, and the outlet of fermentation liquid of bioreactor 2 is connected to the feed port of pervaporation membrane module 3 , the retentate outlet of the pervaporation membrane module 3 is connected with the material inlet of the bioreactor 2 .

The specific embodiment part of the present invention also provides the processing method of the above-mentioned system of fermenting syngas to produce alcohols, said method comprising the following steps:

(a) After the synthesis gas is processed by the bubble-free gas supply membrane module 1, it is sent to the bioreactor 2 for fermentation treatment to synthesize alcohols;

(b) Send the alcohols synthesized in step (a) into the pervaporation membrane module 3 for pervaporation, the obtained alcohol vapor is condensed to obtain alcohol concentrated liquid, and the retained liquid obtained by pervaporation is returned for fermentation treatment.

In each of the following examples, the bacterial strain Clostridiumcarboxidivorans P7 (ATCC BAA-624) purchased from the American Standard Biological Collection Center is adopted, and the ATCC1745PETC medium is adopted to produce ethanol and/or butanol as an example to illustrate the technical scheme of this patent. The cultivation scheme of the seeds is as follows: sterile ATCC1745PETC medium is filled with 80 mL in a 125 mL serum bottle, pH=6.0, and a mixture of 50% CO, 30% _H2 and 20% _CO2 is used before inoculation. Aerate with air for 5 minutes, adjust the pressure inside the bottle to 0.1MPa, then replace the gas in the serum bottle with mixed gas every 24 hours, and incubate at 37°C for 72 hours.

The average concentration of alcohols described in the following examples and comparative examples refers to: (alcohol concentration in the fermentation broth × fermentation broth volume+alcohol concentration of pervaporation condensate × condensate volume)/(fermentation broth volume + condensate volume), which indicates the comprehensive situation of fermentation, that is, the better the degree of fermentation, the higher the value obtained.

The following are typical but non-limiting embodiments of the present invention:

Example 1:

As shown in 1, this embodiment provides a system for fermenting syngas to produce alcohols. The system includes a bubble-free gas supply membrane module 1, a bioreactor 2 and a pervaporation membrane module 3, wherein the bubble-free gas supply membrane Module 1 is placed in bioreactor 2, the air inlet of bubble-free gas supply membrane module 1 is connected to syngas, the fermentation broth outlet of bioreactor 2 is connected to the feed port of pervaporation membrane module 3, and the pervaporation membrane module 3 The retentate outlet of the bioreactor 2 is connected with the material inlet of the bioreactor 2.

Wherein, the bubble-free air-supply membrane module 1 is placed below the liquid level of the fermentation liquid in the bioreactor 2, and is in direct contact with the fermentation liquid in the bioreactor 2; the bubble-free air-supply membrane module 1 is set individually, and the air is fed at both ends;

The gas partial pressure in the bubble-free gas supply membrane module 1 is lower than the bubble pressure, and the curtain-type polypropylene hollow fiber membrane module is built in the bubble-free gas supply membrane module 1. The outer diameter of the hollow fiber membrane is 1.16mm, and the wall thickness is 0.36mm. , the pore size is 0.04 μm, and the gas partial pressure in the hollow fiber membrane is 0.08 MPa;

The pervaporation membrane module 3 is provided with a pervaporation preferential alcohol permeation membrane, which is in the form of a roll and is arranged individually;

A tail gas outlet and a feeding port are provided on the bioreactor 2, and a power delivery pump is provided between the fermentation liquid outlet of the bioreactor 2 and the feed port of the pervaporation membrane module 3.

The processing method of the system is:

(1) Place 7.5L of the sterile ATCC1745PETC medium after seed cultivation in bioreactor 2 with a liquid volume of 5.0L. Before inoculation, it is aerated with N ₂ for 3 hours, and the medium containing CO, H ₂ , CO ₂ and N ₂ synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) was aerated by bubble-free gas supply membrane module 1 for 3 hours, and the aeration rate was 0.05L/min , enter bioreactor 2 to carry out fermentation treatment, the fermentation temperature is 40 ℃, the pH of fermentation treatment is 6.0, the inoculum size is 10%, the pressure in bioreactor 2 is 1 atmospheric pressure, fermentation 10 days, the replenishment of bioreactor 2 Candy is not added to the feed liquid, and the dilution rate is 0.027h ^-1 , and finally ethanol and butanol are synthesized;

(2) Send the alcohols synthesized in step (1) into the pervaporation membrane module 3 for pervaporation, the temperature of pervaporation is 40°C, the obtained alcohol vapor is condensed to obtain ethanol and butanol concentrate, and the pervaporation obtains The retentate returns to carry out fermentation treatment;

(3) Escape gas in the fermentation process described in step (1), the escaping gas is separated by condensation, after separating ethanol, butanol and water from the escaping gas, the fermentation tail gas is obtained, and the gained fermentation tail gas is obtained by using Ca(OH) ₂ solution adsorption method separates CO ₂ and then mixes with the syngas in step (1) to be treated by bubble-free gas supply membrane module 1.

In this embodiment, the final average concentration of ethanol is 25.1 g/L, and the average concentration of butanol is 5.3 g/L.

Example 2:

This embodiment provides a system for fermenting synthesis gas to produce alcohols. The system described in Embodiment 1 is the same as that in Embodiment 1 except that the pore size of the hollow polypropylene hollow fiber membrane is 0.8 μm. The system structure is the same.

The processing method of the system is:

(1) Place 7.5L of the sterile ATCC1745PETC medium after seed cultivation in bioreactor 2 with a liquid volume of 5.0L. Before inoculation, it is aerated with N ₂ for 3 hours, and the medium containing CO, H ₂ , CO ₂ and N ₂ synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) was aerated by bubble-free gas supply membrane module 1 for 3 hours, and the aeration rate was 0.05L/min , enter the bioreactor 2 for fermentation treatment, the fermentation temperature is 30°C, the pH of the fermentation treatment is 6.0, the inoculum size is 10%, the pressure in the bioreactor 2 is 1 atmosphere, and the fermentation is 10 days. The replenishment of the bioreactor 2 Candy is not added to the feed liquid, and the dilution rate is 0.027h ^-1 , and finally ethanol and butanol are synthesized;

(2) Send the alcohols synthesized in step (1) into the pervaporation membrane module 3 for pervaporation, the pervaporation temperature is 30°C, the obtained alcohol vapor is condensed to obtain ethanol and butanol concentrate, and the pervaporation obtains The retentate returns to carry out fermentation treatment;

(3) Escape gas in the fermentation process described in step (1), separate the escaping gas, and after separating ethanol, butanol and water from the escaping gas, obtain the fermentation tail gas, and the gained fermentation tail gas adopts Ca(OH ) _2. After separating CO ₂ by solution adsorption method, it is mixed with the synthesis gas in step (1) and treated by the bubble-free gas supply membrane module 1.

In this embodiment, the final average concentration of ethanol is 21.3g/L, and the average concentration of butanol is 4.5g/L.

Comparative example 1:

This comparative example provides a method for fermenting syngas to produce alcohols, which only reacts in a bioreactor and does not include bubble-free gas supply treatment and pervaporation treatment. The method is:

Put 7.5L of the sterile ATCC1745PETC medium after seed cultivation into a bioreactor with a liquid volume of 5.0L. Before inoculation, use N ₂ to aerate for 3 hours, and put CO, H ₂ , CO ₂ and N ₂ The synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) is sent to the bioreactor for fermentation treatment, aeration for 3 hours, aeration rate 0.05L/min, fermentation temperature The temperature is 40°C, the pH of the fermentation treatment is 6.0, the pressure inside the bioreactor is 1 atmosphere, the fermentation is for 10 days, the dilution rate is 0.027h ^-1 , and finally ethanol and butanol are synthesized.

In this comparative example, the average concentration of ethanol is 2.0g/L, and the average concentration of butanol is 0.5g/L.

Comparative example 2:

This comparative example provides a system for fermenting syngas to produce alcohols. The system is the same as in Example 1 except that the pervaporation membrane module 3 is not included.

Its processing method is:

Put 7.5L of the sterile ATCC1745PETC medium after seed cultivation into bioreactor 2, with a liquid volume of 5.0L, and aerate with N ₂ for 3 hours before inoculation, and will contain CO, H ₂ , CO ₂ and N ₂ synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) is aerated by bubble-free gas supply membrane module 1 for 3 hours at an aeration rate of 0.05L/min, and enters Bioreactor 2 carries out fermentation treatment, fermentation temperature is 40 ℃, the pH of fermentation treatment is 6.0, the inoculum size is 10%, the internal pressure of bioreactor 2 is 1 atmospheric pressure, fermentation 10 days, the feeding liquid of bioreactor 2 Candy is not added to the mixture, the dilution rate is 0.027h ^-1 , and ethanol and butanol are finally synthesized.

In this comparative example, the average concentration of ethanol is 11.5g/L, and the average concentration of butanol is 2.4g/L.

Comparative example 3:

This comparative example provides a system for fermenting synthesis gas to produce alcohols. The system is the same as in Example 1 except that the bubble-free gas supply membrane module 1 is not included.

Its processing method is:

(1) Place 7.5L of the sterile ATCC1745PETC medium after seed cultivation in a bioreactor with a liquid volume of 5.0L. Before inoculation, use N ₂ to aerate for 3 hours, and will contain CO, H ₂ , CO ₂ and N ₂ synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) is sent to the bioreactor for fermentation treatment, aeration 3h, aeration rate 0.05L/min, The pH of the fermentation treatment is 6.0, the pressure in the bioreactor is 1 atmosphere, the fermentation is for 10 days, the dilution rate is 0.027h ^-1 , and finally ethanol and butanol are synthesized.

(2) Send the alcohols synthesized in step (1) into the pervaporation membrane module 3 for pervaporation, and the obtained alcohol vapors are condensed to obtain ethanol and butanol concentrates, and the pervaporation retentates are returned for fermentation treatment.

In this comparative example, the average concentration of ethanol is 9.8g/L, and the average concentration of butanol is 1.3g/L.

Example 3:

As shown in Figure 2, this embodiment provides a system for fermenting syngas to produce alcohols, the system includes a bubble-free gas supply membrane module 1, a bioreactor 2 and a pervaporation membrane module 3, wherein the bubble-free gas supply The membrane module 1 is placed outside the bioreactor 2, the air inlet of the bubble-free gas supply membrane module 1 is connected to the syngas, the fermentation broth outlet of the bioreactor 2 is connected to the feed port of the pervaporation membrane module 3, and the pervaporation membrane module The retentate outlet of 3 is connected with the material inlet of bioreactor 2.

Wherein, the fermentation liquid in the bioreactor 2 is connected to the liquid inlet of the bubble-free gas supply membrane module 1 through a delivery pump, and the liquid outlet of the bubble-free gas supply membrane module 1 is connected to the feed port of the bioreactor 2 .

The gas partial pressure in the bubble-free gas supply membrane module 1 is lower than the bubble pressure, and the bubble-free gas supply membrane module 1 has a built-in cylindrical polyethylene hollow fiber membrane module, the outer diameter of the hollow fiber membrane is 1.16mm, and the wall thickness is 0.36mm , the pore size is 0.04 μm, and the gas partial pressure in the hollow fiber membrane is 0.08 MPa;

The pervaporation membrane module 3 is provided with a pervaporation preferential alcohol permeation membrane, which is in the form of a tube and is arranged individually;

A tail gas outlet and a feeding port are provided on the bioreactor 2, and a power delivery pump is provided between the fermentation liquid outlet of the bioreactor 2 and the feed port of the pervaporation membrane module 3.

The processing method of the system is:

(1) Place 7.5L of the sterile ATCC1745PETC medium after seed cultivation in bioreactor 2 with a liquid volume of 5.0L. Before inoculation, it is aerated with N ₂ for 3 hours, and the medium containing CO, H ₂ , CO ₂ and N ₂ synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) was aerated by bubble-free gas supply membrane module 1 for 3 hours, and the aeration rate was 0.05L/min , enter the bioreactor 2 for fermentation treatment, the fermentation temperature is 50 ° C, the pH of the fermentation treatment is 6.0, the inoculum size is 10%, the pressure in the bioreactor 2 is 1 atmosphere, and the fermentation is 10 days. The replenishment of the bioreactor 2 Candy is not added to the feed liquid, and the dilution rate is 0.027h ^-1 , and finally ethanol and butanol are synthesized;

(2) Send the alcohols synthesized in step (1) into the pervaporation membrane module 3 for pervaporation. The liquid is returned for fermentation treatment;

(3) Escape gas in the fermentation process described in step (1), the escaping gas is separated by condensation, after separating ethanol, butanol and water from the escaping gas, the fermentation tail gas is obtained, and the gained fermentation tail gas is obtained by using Ca(OH) ₂ solution adsorption method separates CO ₂ and then mixes with the syngas in step (1) to be treated by bubble-free gas supply membrane module 1.

In this embodiment, the average concentration of ethanol is 32.6g/L, and the average concentration of butanol is 10.6g/L.

Example 4:

This embodiment provides a system for fermenting synthesis gas to produce alcohols. The system described in Embodiment 3 is the same as that in Embodiment 3 except that the pore diameter of the hollow polyethylene hollow fiber membrane is 0.8 μm. The system structure is the same. The processing method of the system is the same as that in Embodiment 3.

In this embodiment, the average concentration of ethanol is 25.7g/L, and the average concentration of butanol is 8.7g/L.

Comparative example 4:

This comparative example provides a system for fermenting syngas to produce alcohols. The system is the same as in Example 3 except that the pervaporation membrane module 3 is not included.

Its processing method is:

Put 7.5L of the sterile ATCC1745PETC medium after seed cultivation into bioreactor 2, with a liquid volume of 5.0L, and aerate with N ₂ for 3 hours before inoculation, and will contain CO, H ₂ , CO ₂ and N ₂ synthesis gas (volume concentration: CO 20%, H ₂ 5%, CO ₂ 15% and N ₂ 60%) is aerated by bubble-free gas supply membrane module 1 for 3 hours at an aeration rate of 0.05L/min, and enters The bioreactor 2 is subjected to fermentation treatment, the fermentation temperature is 50°C, the pH of the fermentation treatment is 6.0, the inoculum size is 10%, the pressure in the bioreactor 2 is 1 atmosphere, and the fermentation is for 10 days. The feeding liquid of the bioreactor 2 Candy is not added to the mixture, the dilution rate is 0.027h ^-1 , and ethanol and butanol are finally synthesized.

In this comparative example, the average concentration of ethanol is 15.3g/L, and the average concentration of butanol is 3.6g/L.

Comparative example 5:

This comparative example provides a system for fermenting syngas to produce alcohols, except that the pervaporation membrane module 3 is not included in the system, and the pore size of the polyethylene hollow fiber membrane is 0.8 μm, and other structures are the same as those in Example 3 .

The treatment method is the same as in Comparative Example 4, and ethanol and butanol are finally synthesized.

In this comparative example, the average concentration of ethanol is 12.6g/L, and the average concentration of butanol is 2.1g/L.

Combining Examples 1-5 and Comparative Examples 1-5, it can be seen that the present invention adopts double-end or single-end air intake bubble-free gas supply membrane technology, and combines fermentation-pervaporation separation coupling fermentation technology, which can improve mixed gas fermentation. The gas-liquid transmission rate, gas utilization efficiency, microbial cell concentration and product concentration in the process reduce the material consumption of the cultured cells, increase the cell density in the fermentation process, and increase the fermentation efficiency and product concentration.

The applicant declares that the present invention illustrates the detailed methods of the present invention through the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed methods, that is, it does not mean that the present invention must rely on the above-mentioned detailed methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. it is a kind of ferment synthesis gas produce alcohols system, it is characterised in that the system include it is still supply membrane module (1), Bioreactor (2) and infiltration vaporization membrane module (3), wherein still supply membrane module (1) is placed in bioreactor (2) or puts In bioreactor (2) outward, the air inlet connection synthesis gas of still supply membrane module (1), the zymotic fluid of bioreactor (2) goes out Mouth is connected with the charging aperture of infiltration vaporization membrane module (3), and the trapped fluid of infiltration vaporization membrane module (3) is exported and bioreactor (2) material inlet is connected.

2. system according to claim 1, it is characterised in that when still supply membrane module (1) is placed in bioreactor (2) When interior, still supply membrane module (1) is placed in below the liquid level of bioreactor (2) interior zymotic fluid, with hair in bioreactor (2) Zymotic fluid directly contact；

Preferably, when it is still supply membrane module (1) be placed in bioreactor (2) it is outer when, bioreactor (2) interior zymotic fluid passes through Delivery pump is connected with the inlet of still supply membrane module (1), the liquid outlet and bioreactor of still supply membrane module (1) (2) charging aperture is connected.

3. system according to claim 1 and 2, it is characterised in that described still supply membrane module (1) interior partial pressure is low In bubble pressure；

Preferably, built-in hollow fiber film assembly, tubular membrane component or plate type membrane assembly in still supply membrane module (1) In any one or at least two combination, preferably hollow fiber film assembly；

Preferably, the hollow fiber film assembly is by polyethylene, polypropylene, polyacrylonitrile, polysulfones, polyether sulfone, polyvinylidene fluoride The microporous breathable film that any one material or at least two materials are made in alkene or polytetrafluoroethylene (PTFE)；

Preferably, the external diameter of the hollow-fibre membrane is 0.02mm~4.0mm, and wall thickness 0.01mm~0.7mm, aperture is 0.04 μm ~0.8 μm；

Preferably, partial pressure ＜ 0.5MPa in the hollow-fibre membrane；

Preferably, when it is described it is still supply membrane module (1) be placed in bioreactor (2) it is interior when, its built-in hollow-fibre membrane group Part is curtain hollow fiber film assembly and/or cartridge type hollow fiber film assembly；

Preferably, when still supply membrane module (1) be placed in bioreactor (2) it is outer when, its internal hollow-fibre membrane group Part is cartridge type hollow fiber film assembly.

4. the system according to claim any one of 1-3, it is characterised in that still supply membrane module (1) is single Or at least two be arranged in parallel；

Preferably, still supply membrane module (1) is single-ended air inlet or two ends air inlet；

Preferably, it is provided with seepage slope ethanol-permselective membrane in the infiltration vaporization membrane module (3)；

Preferably, the seepage slope ethanol-permselective membrane by organic film, inoranic membrane or hybrid organic-inorganic film any one or At least two prepare；

Preferably, organic membrane material is any one in silicon rubber, poly- trimethyl silicane propane, polypropylene or Kynoar Or at least two combination；

Preferably, the material of the inoranic membrane is Silicalite-1 and/or ZSM-5；

Preferably, the material of the hybrid organic-inorganic film is PDMS-Silicalite-1, PDMS-ZSM-5 or PTMSP- In Silicalite-1 any one or at least two combination；

Preferably, the form of the infiltration vaporization membrane module (3) be rolled membrane module, tubular membrane component, plate and frame module or In hollow fiber form membrane module any one or at least two combination；

Preferably, the infiltration vaporization membrane module (3) is the setting of single or at least two serial or parallel connections；

Preferably, the serial or parallel connection of the infiltration vaporization membrane module (3) is led to by the per-meate side of infiltration vaporization membrane module (3) Cross pipeline serial or parallel connection；

Preferably, offgas outlet and material-feeding port are set on the bioreactor (2)；

Preferably, it is provided with dynamic between the zymotic fluid outlet of the bioreactor (2) and the charging aperture of infiltration vaporization membrane module (3) Power delivery pump.

5. a kind of synthesis gas that fermented according to claim any one of 1-4 produces the processing method of the system of alcohols, its feature It is that the described method comprises the following steps：

A () processes synthesis gas through still supply membrane module (1) after, feeding bioreactor (2) carries out fermentation process, synthol Class；

B alcohols that () synthesizes step (a) carries out infiltration evaporation, gained alcohol vapor warp in sending into infiltration vaporization membrane module (3) Condensation obtains alcohols concentrate, and the trapped fluid that infiltration evaporation is obtained comes back for fermentation process.

6. method according to claim 5, it is characterised in that synthesis gas described in step (a) contains CO and/or H₂；

Preferably, the alcohols for synthesizing described in step (a) is ethanol and/or butanol；

Preferably, the concentration of ethanol is 0.5g/L~50g/L in bioreactor described in step (a) (2) built-in zymotic fluid；

Preferably, the concentration of butanol is 0.5g/L~20g/L in bioreactor described in step (a) (2) built-in zymotic fluid；

Preferably, fermentation process microorganism used therefor described in step (a) be Clostridium ljungdahlii, In Clostridium carboxidivorans or Butyribacterium methylotrophicum any one.

7. the method according to claim 5 or 6, it is characterised in that fermentation process described in step (a) was to continuously ferment Journey or interval batch fermentation process；

Preferably, the medium component of not carbonaceous sources is supplemented in the Continuous Fermentation Processes；

Preferably, the fermentation temperature of fermentation process described in step (a) is 30 DEG C~50 DEG C.

8. the method according to claim any one of 5-7, it is characterised in that the treatment of infiltration evaporation described in step (b) Temperature is 30 DEG C~50 DEG C；

Preferably, the concentration of ethanol is 10g/L~500g/L in the alcohols concentrate that step (b) condensation is obtained；

Preferably, the concentration of butanol is 10g/L~200g/L in the alcohols concentrate that step (b) condensation is obtained.

9. the method according to claim any one of 5-8, it is characterised in that methods described also includes step (c)：

Emergent gas in step (a) fermentation process, is separated to escaping gas, and alcohol is isolated from escaping gas After class and water, fermentation tail gas, the separated CO of gained fermentation tail gas are obtained₂Mix through still supply with synthesis gas in step (a) afterwards Membrane module (1) treatment；

Preferably, the alcohols and the method for water isolated from emergent gas is condensation method, membrane separation process or solvent absorption In any one or at least two combination；

Preferably, CO is separated from the fermentation tail gas₂Method be absorption method and/or membrane separation process.

10. the method according to claim any one of 5-9, it is characterised in that the described method comprises the following steps：

A () will contain CO and/or H₂Synthesis gas through it is still supply membrane module (1) process after, feeding bioreactor (2) carry out Fermentation process, synthesizing alcohol and/or butanol；

Wherein, the concentration of ethanol is 0.5g/L~50g/L in bioreactor (2) built-in zymotic fluid；Bioreactor (2) is built-in The concentration of butanol is 0.5g/L~20g/L in zymotic fluid；

Fermentation process microorganism used therefor be Clostridium ljungdahlii, Clostridium carboxidivorans or In Butyribacterium methylotrophicum any one；

B alcohols that () synthesizes step (a) carries out infiltration evaporation, gained alcohol vapor warp in sending into infiltration vaporization membrane module (3) Condensation obtains alcohols concentrate, and the trapped fluid that infiltration evaporation is obtained comes back for fermentation process；

The concentration for condensing ethanol in the alcohols concentrate for obtaining is 10g/L~500g/L；

The concentration for condensing butanol in the alcohols concentrate for obtaining is 10g/L~200g/L；

C emergent gas in () step (a) described fermentation process, separates to escaping gas, separated from escaping gas After going out alcohols and water, fermentation tail gas, the separated CO of gained fermentation tail gas are obtained₂Mix through still with synthesis gas in step (a) afterwards Supply membrane module (1) treatment.