Product extraction device for producing acetone by fermentation of synthesis gas

Abstract

The utility model relates to a product extraction device for producing acetone by synthesis gas fermentation, which comprises a synthesis gas fermentation tank, a gas condensation pipe, an acetone storage tank and an adsorption tower, the synthesis gas fermentation tank is used for preparing acetone based on synthesis gas fermentation, and the top of the synthesis gas fermentation tank is provided with a gas outlet; the gas condensation pipe is provided with a gas inlet, a condensate discharge port and a gas discharge port, the gas inlet of the gas condensation pipe is communicated with the gas discharge port of the synthesis gas fermentation tank, and the condensate discharge port of the gas condensation pipe is communicated to the acetone storage tank; the adsorption tower is provided with a gas inlet and a gas outlet which are opposite to each other, the adsorption tower is filled with adsorption particles, the adsorption particles are used for adsorbing acetone, and the gas inlet of the adsorption tower is communicated with the gas outlet of the gas condensation pipe. Compared with a traditional distillation method, by means of condensation and adsorption, the energy consumption is relatively low, the cost is relatively low, and recycling is relatively easy.

Description

Technical Field

[0001] This utility model relates to the field of acetone fermentation technology, and in particular to a product extraction device for acetone production by syngas fermentation. Background Technology

[0002] In recent years, syngas fermentation technology has attracted attention as an emerging bio-fermentation method. This technology utilizes autotrophic microorganisms to convert syngas (mainly composed of carbon monoxide, carbon dioxide, and hydrogen) into chemicals such as acetone via the Wood-Ljungdahl pathway. Although syngas fermentation has advantages such as a wide range of raw material sources and the ability to achieve carbon recycling, it still faces some challenges in practical applications. For example, the gas transport efficiency during fermentation is relatively low, resulting in insufficient utilization of syngas by microorganisms; at the same time, the concentration of fermentation products is low, requiring further optimization of fermentation conditions and strain performance.

[0003] The separation and purification technology for acetone production from syngas bio-fermentation still faces multiple challenges. In syngas fermentation, the acetone concentration is typically below 5%, and it coexists with byproducts such as isopropanol, ethanol, and organic acids, forming a highly diluted and complex mixture. Traditional distillation methods are energy-intensive due to the high water content (requiring the evaporation of large amounts of water), resulting in poor economic efficiency. Furthermore, maintaining cell activity is crucial in thermophilic fermentation systems during separation; conventional solid-liquid separation techniques (such as centrifugation and filtration) can easily lead to cell loss or metabolic inhibition. While pressurized fermentation processes (e.g., 0.7 MPa) can increase the reaction rate, the boiling point of acetone rises above 130°C with increasing pressure, making gas phase recovery difficult. Utility Model Content

[0004] Therefore, it is necessary to provide a product extraction device for acetone production by syngas fermentation that has relatively low energy consumption, relatively low cost, and relatively easy recovery.

[0005] A product extraction device for acetone production via syngas fermentation includes a syngas fermenter, a gas condenser, an acetone storage tank, and an adsorption tower, wherein:

[0006] The syngas fermenter is used to produce acetone based on syngas fermentation, and the top of the syngas fermenter has a gas outlet.

[0007] The gas condenser has an air inlet, a condensate outlet, and a gas outlet. The air inlet of the gas condenser is connected to the gas outlet of the syngas fermenter, and the condensate outlet of the gas condenser is connected to the acetone storage tank.

[0008] The adsorption tower has a corresponding air inlet and an air outlet. The adsorption tower is filled with adsorption particles, which are used to adsorb acetone. The air inlet of the adsorption tower is connected to the gas outlet of the gas condenser.

[0009] In one embodiment, the adsorption tower is an activated carbon adsorption tower, which is filled with activated carbon.

[0010] In one embodiment, the gas condenser is a stepped-temperature gas condenser.

[0011] In one embodiment, the gas condenser includes a primary condenser, a mid-temperature condenser, and a cryogenic condenser connected in sequence. The temperature of the cooling medium in the primary condenser is higher than that in the mid-temperature condenser, and the temperature of the cooling medium in the cryogenic condenser is lower than that in the mid-temperature condenser. The condensate outlets of the mid-temperature condenser and the cryogenic condenser are both connected to the acetone storage tank.

[0012] In one embodiment, the product extraction device further includes a combustion tower, the inlet of which is connected to the outlet of the adsorption tower.

[0013] In one embodiment, the adsorption tower has a recovery port that is connected to the inlet of the gas condenser.

[0014] In one embodiment, the product extraction apparatus further includes a short-path distillation column connected to the acetone storage tank, the short-path distillation column being used to distill and purify the crude acetone in the acetone storage tank.

[0015] In one embodiment, the shell of the short-path distillation column is made of 316L stainless steel.

[0016] In one embodiment, the initial condenser tube is a plate heat exchanger;

[0017] And / or, the medium-temperature section condenser is a shell-and-tube condenser.

[0018] In one embodiment, the cryogenic section condenser is a spiral plate cryogenic condenser.

[0019] The aforementioned acetone extraction apparatus for syngas fermentation typically contains acetone and other byproducts in its exhaust gas because the temperature of the syngas fermenter is usually 58-60 degrees Celsius, while acetone begins to volatilize significantly when it reaches its boiling point of 56.2 degrees Celsius. Firstly, the acetone is condensed using a gas condenser, and then the uncondensed acetone is adsorbed and recovered using an adsorption tower, ensuring an acetone recovery rate of over 99.5% in the fermentation product. Compared to traditional distillation methods, this application, through condensation and adsorption, has relatively lower energy consumption, lower cost, and easier recovery.

[0020] In other preferred embodiments, by employing a stepped-temperature gas condenser, particularly a structure design incorporating a preliminary condenser, a mid-temperature condenser, and a cryogenic condenser, the purity of the acetone product can be further improved, and byproducts can be removed. Utilizing the boiling point difference between CO2 / H2 and acetone (a difference exceeding 300°C), efficient phase change separation is achieved through gradient cooling, reducing equipment investment costs by 30% compared to membrane separation systems. No vacuum or high-pressure equipment is required throughout the process (only short-path distillation uses 10-20 kPa low pressure), reducing equipment failure risks and maintenance frequency. Furthermore, the activated carbon adsorption tower and condenser support online switching, ensuring continuous production (downtime <1%) and a capacity fluctuation rate ≤2%. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the product extraction device for acetone production by syngas fermentation according to an embodiment of the present invention. Detailed Implementation

[0022] To facilitate understanding of this utility model and to make the aforementioned objects, features, and advantages of this utility model more apparent, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this utility model, and preferred embodiments are shown in the accompanying drawings. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model. This utility model can be implemented in many other ways different from those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of this utility model; therefore, this utility model is not limited to the specific embodiments disclosed below. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the utility model. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Please see Figure 1 This application provides a product extraction device for acetone production via syngas fermentation, comprising a syngas fermenter 100, a gas condenser 200, an acetone storage tank 400, and an adsorption tower 300, wherein:

[0024] The syngas fermenter 100 is used to produce acetone based on syngas fermentation. The fermenter has a gas exhaust port at the top. Specifically, syngas fermentation utilizes autotrophic microorganisms to convert syngas (mainly composed of carbon monoxide, carbon dioxide, and hydrogen) into chemicals such as acetone via the Wood-Ljungdahl pathway. For example, *Moorella thermoacetica* is typically used as the microbial cell, which produces acetone by fermenting CO2 and H2 at 60°C. Since the temperature of the syngas fermenter is typically 58-60°C, and acetone begins to volatilize significantly when it reaches its boiling point of 56.2°C, the exhaust gas from the syngas fermenter usually contains acetone and other byproducts. It should be noted that how to prepare acetone from syngas using *Moorella thermoacetica* can be found in previous patents of the applicant and related parties, and will not be elaborated upon here.

[0025] The gas condenser 200 is used to cool the exhaust gas from the syngas fermenter 100, thereby recovering acetone. The gas condenser 200 has an inlet, a condensate outlet, and a gas outlet. The inlet of the gas condenser 200 is connected to the gas outlet of the syngas fermenter 100, and the condensate outlet of the gas condenser 200 is connected to the acetone storage tank 400. The acetone storage tank 400 is used to collect the initially condensed acetone for further purification, such as distillation.

[0026] The adsorption tower 300 has opposing inlets and outlets. The adsorption tower 300 is filled with adsorption particles for adsorbing acetone. The inlet of the adsorption tower 300 is connected to the gas outlet of the gas condenser 200. In other words, acetone that has not been condensed by the gas condenser 200 can be further adsorbed and recovered by the adsorption tower 300. For example, the adsorption tower can be an activated carbon adsorption tower filled with activated carbon, or a two-stage activated carbon adsorption tower. In this application, for uncondensed trace amounts of acetone (<100ppm), a two-stage activated carbon adsorption tower is used, with an adsorption efficiency ≥99.5%. After adsorption saturation, acetone is recovered by steam desorption (120-150℃), and the desorbed gas is returned to the primary condenser for re-liquefaction. For example, the adsorption tower 300 has a recovery port connected to the inlet of the gas condenser. Alternatively, valves can be installed on the recovery port and the inlet of the gas condenser. It should be noted that valves can be installed on each connecting passage in this application as needed, and this application will not describe the valves separately. For example, when the adsorption tower uses steam desorption, the temperature is controlled at 120-150℃ and the operating pressure is atmospheric pressure, and the activated carbon can be regenerated by steam, thus facilitating recycling.

[0027] The aforementioned acetone extraction apparatus for syngas fermentation typically contains acetone and other byproducts in its exhaust gas because the temperature of the syngas fermenter is usually 58-60 degrees Celsius, while acetone begins to volatilize significantly when it reaches its boiling point of 56.2 degrees Celsius. Firstly, the acetone is condensed using a gas condenser, and then the uncondensed acetone is adsorbed and recovered using an adsorption tower, ensuring an acetone recovery rate of over 99.5% in the fermentation product. Compared to traditional distillation methods, this application, through condensation and adsorption, has relatively lower energy consumption, lower cost, and easier recovery.

[0028] In addition to acetone, the products of a syngas fermenter also contain other byproducts such as isopropanol, ethanol, and organic acids. Furthermore, a significant amount of water vapor is also present in the products. To further improve the purity of acetone recovery, in one embodiment, the gas condenser is a stepped-temperature gas condenser. For details, please refer to... Figure 1 For example, the gas condenser 200 includes a primary condenser 210, a medium-temperature condenser 220, and a cryogenic condenser 230 connected in sequence. The temperature of the cooling medium in the primary condenser 210 is higher than that in the medium-temperature condenser 220, and the temperature of the cooling medium in the cryogenic condenser 230 is lower than that in the medium-temperature condenser 220. The condensate outlets of the medium-temperature condenser 220 and the cryogenic condenser 230 are both connected to the acetone storage tank. In this embodiment:

[0029] First, preliminary condensation is performed using a primary condenser. The gas exiting the fermenter (60°C) contains acetone vapor, CO2, H2, and a small amount of water vapor. This gas first enters the primary condenser, where its temperature is reduced to 50-55°C (slightly below the boiling point of acetone). Most of the water vapor (boiling point 100°C) is condensed, reducing the load on subsequent systems. Acetone remains in a gaseous state, preventing premature liquefaction and potential pipe blockage. For example, the primary condenser is a plate heat exchanger made of material resistant to acetone corrosion, such as 316L stainless steel. Alternatively, the primary condenser reduces the temperature of the gas exiting the syngas fermenter to 50-55°C using a plate heat exchanger, operating at atmospheric pressure.

[0030] Secondly, the intermediate-temperature condenser further reduces the gas temperature to 0-5℃, achieving an acetone vapor liquefaction rate of over 95%. The condensate (crude acetone) is collected in a storage tank, while the uncondensed gas enters the next stage. For example, the intermediate-temperature condenser further reduces the gas temperature discharged from the syngas fermenter to 0-5℃, and the pressure can be atmospheric or slightly positive. For example, slightly positive pressure ranges from 10 Pa to 300 Pa. The intermediate-temperature condenser can be a shell-and-tube condenser.

[0031] Secondly, cryogenic condensers are used to cool the gas to below -20°C, further recovering residual acetone (purity ≥99%). The final acetone concentration in the exhaust gas can be reduced to below 100 ppm, meeting emission standards. For example, liquid nitrogen can be used as the cooling medium in cryogenic condensers, although other low-temperature condensers can also be used. For instance, cryogenic condensers can further reduce the temperature of the gas discharged from the syngas fermenter to below -20°C, while operating at atmospheric pressure.

[0032] In one embodiment, the primary condenser is a plate heat exchanger; for example, the intermediate temperature condenser is a shell-and-tube condenser. For example, the cryogenic condenser is a spiral plate cryogenic condenser.

[0033] In this embodiment, the problem of low-concentration acetone recovery is solved based on multi-gradient condensation. Traditional acetone separation processes (such as vacuum distillation) require operation at low pressure to avoid aldehyde-alcohol reversal reactions, resulting in high equipment investment costs, increased energy consumption (such as vacuum pump power consumption), and a 50% reduction in production capacity. This solution replaces vacuum operation with multi-stage gradient condensation (0 to -20°C) and atmospheric pressure adsorption regeneration, directly utilizing boiling point differences to achieve separation, avoiding the high maintenance costs and production capacity limitations of vacuum systems. The acetone concentration in syngas fermentation broth is usually below 5%, and traditional distillation requires the evaporation of a large amount of water, resulting in extremely high energy consumption. This solution preferentially removes water vapor through pre-condensation (50-55°C), combined with staged liquefaction at medium temperature (0-5°C) and cryogenic temperature (-20°C), achieving an acetone recovery rate of 99.5%, and reducing condensation energy consumption by 40% compared to traditional distillation.

[0034] The trace amounts of acetone (<100ppm) remaining in the exhaust gas are difficult to completely remove through condensation. The proposed solution introduces an activated carbon adsorption tower (adsorption efficiency ≥99.5%), combined with steam desorption and regeneration technology, to ensure that the acetone concentration in the final exhaust gas is below 50ppm, meeting environmental standards.

[0035] In one embodiment, the product extraction device further includes a combustion tower 600, the inlet of which is connected to the outlet of the adsorption tower 300. By setting up the combustion tower, the residual waste gas is treated to completely decompose organic pollutants, avoiding secondary pollution.

[0036] In one embodiment, the product extraction apparatus further includes a short-path distillation column 500, which is connected to the acetone storage tank 400. The short-path distillation column 500 is used to distill and purify the crude acetone in the acetone storage tank 400. After passing through the short-path distillation column, the crude acetone can be used under vacuum conditions (operating temperature 40-50°C) to remove trace amounts of moisture and volatile impurities, thereby increasing the acetone purity to 99.9%. In one embodiment, the shell of the short-path distillation column is made of 316L stainless steel, ensuring good safety. Furthermore, the temperature of the short-path distillation column is controlled at 40-50°C, and the operating pressure is controlled at 10-20 kPa.

[0037] For example, the short-path distillation column 500 has a first distillation outlet 510, a second distillation outlet 520, and a third distillation outlet 530. The first distillation outlet 510 is used to discharge acetone, with a purity of up to 99.9%. The second distillation outlet 520 is used to discharge moisture and volatile impurities. The third distillation outlet 530, located at the top, is used to discharge gases such as carbon monoxide and hydrogen. The third distillation outlet 530 of the short-path distillation column can be connected to a combustion tower or to the syngas for use in a syngas fermenter. Of course, the composition of the syngas needs to be tested, and the syngas composition needs to be supplemented and matched to meet the requirements for syngas use.

[0038] For example, short-path distillation columns utilize the residual heat of the fermentation broth in a syngas fermenter for coupled distillation. A heat pump is used to pump the fermentation broth into the syngas fermenter. Before pumping, the broth passes through a ceramic membrane (0.1-0.2 μm) to retain the cells online and is then returned to the fermenter. The cell activity loss rate is ≤5%, and the fermentation broth circulation rate is ≥98%.

[0039] The aforementioned acetone extraction apparatus for syngas fermentation typically contains acetone and other byproducts in its exhaust gas because the temperature of the syngas fermenter is usually 58-60 degrees Celsius, while acetone begins to volatilize significantly when it reaches its boiling point of 56.2 degrees Celsius. Firstly, the acetone is condensed using a gas condenser, and then the uncondensed acetone is adsorbed and recovered using an adsorption tower, ensuring an acetone recovery rate of over 99.5% in the fermentation product. Compared to traditional distillation methods, this application, through condensation and adsorption, has relatively lower energy consumption and is easier to recover the acetone.

[0040] In other preferred embodiments, by employing a stepped-temperature gas condenser, particularly a structure design incorporating a preliminary condenser, a mid-temperature condenser, and a cryogenic condenser, the purity of the acetone product can be further improved, and byproducts can be removed. Utilizing the boiling point difference between CO2 / H2 and acetone (a difference exceeding 300°C), efficient phase change separation is achieved through gradient cooling, reducing equipment investment costs by 30% compared to membrane separation systems. No vacuum or high-pressure equipment is required throughout the process (only short-path distillation uses 10-20 kPa low pressure), reducing equipment failure risks and maintenance frequency. Furthermore, the activated carbon adsorption tower and condenser support online switching, ensuring continuous production (downtime <1%) and a capacity fluctuation rate ≤2%.

[0041] In this application, compared to the traditional cumene process (co-producing phenol, complex equipment) and chromatographic purification processes (relying on molecularly imprinted adsorption and distillation), this solution, through a separation logic dominated by physical phase change, overcomes the dependence of chemical methods on raw material purity and can directly process fermentation gas containing complex impurities. Its core value lies in: Industrialization potential: Equipment selection (e.g., 316L stainless steel) is compatible with corrosive environments and suitable for multiple scenarios such as syngas fermentation and biomass conversion. Cost competitiveness: Overall energy consumption is reduced by 50% compared to the cumene process, and the production cost per ton of acetone drops to below US$1200 (compared to approximately US$1800 for traditional processes). In the future, energy efficiency can be further improved through integrated heat pump technology, promoting the large-scale commercial application of bio-based acetone.

[0042] In this application, an acetone recovery rate of ≥99.5% is achieved by using a protected gradient temperature control logic: a segmented cooling process of pre-condensation (50-55℃) → primary condensation (0-5℃) → secondary cryogenic (-20℃), combined with the steam desorption and regeneration technology of an activated carbon adsorption tower. A fluid control method that eliminates the need for pressure reduction and boosting is also employed: acetone is separated from CO2 / H2 based on their boiling point differences through atmospheric pressure operation, avoiding the need for high-pressure equipment (such as vacuum pumps) and reducing system complexity.

[0043] The stepped condensation + activated carbon adsorption method of this application is illustrated by the following example data: In Example 1, after corn straw sugar solution fermentation and 12 hours of coupled pervaporation membrane separation, the ABE yield increased by 50%, and energy consumption was reduced by 40% compared to traditional distillation. Comparative experiment: Compared to the traditional salting-out method, alkaline extraction (NaOH 0.1-0.2 g / L) saves 90% of salt consumption and reduces extractant cost by 60%.

[0044] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again," etc., in this application are intended to illustrate the application and not to limit it. The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A product extraction device for acetone production via syngas fermentation, characterized in that, Includes a syngas fermenter, gas condenser, acetone storage tank, and adsorption tower, wherein: The syngas fermenter is used to produce acetone based on syngas fermentation, and the top of the syngas fermenter has a gas outlet. The gas condenser has an air inlet, a condensate outlet and a gas outlet. The air inlet of the gas condenser is connected to the gas outlet of the syngas fermenter, and the condensate outlet of the gas condenser is connected to the acetone storage tank. The adsorption tower has a corresponding air inlet and an air outlet. The adsorption tower is filled with adsorption particles, which are used to adsorb acetone. The air inlet of the adsorption tower is connected to the gas outlet of the gas condenser.

2. The product extraction device of claim 1, wherein, The adsorption tower is an activated carbon adsorption tower, and the activated carbon adsorption tower is filled with activated carbon.

3. The product extraction device of claim 1, wherein, The gas condenser is a stepped-temperature gas condenser.

4. The product extraction device of claim 3, wherein, The gas condenser includes a primary condenser, a medium-temperature condenser, and a cryogenic condenser connected in sequence. The temperature of the cooling medium in the primary condenser is higher than that in the medium-temperature condenser, and the temperature of the cooling medium in the cryogenic condenser is lower than that in the medium-temperature condenser. The condensate outlets of the medium-temperature condenser and the cryogenic condenser are both connected to the acetone storage tank.

5. The product extraction device of claim 4, wherein, The product extraction device also includes a combustion tower, the inlet of which is connected to the outlet of the adsorption tower.

6. The product extraction device of claim 5, wherein, The adsorption tower has a recovery port, which is connected to the gas inlet of the gas condenser.

7. The product extraction device of claim 4, wherein, The product extraction device also includes a short-path distillation column, which is connected to the acetone storage tank. The short-path distillation column is used to distill and purify the crude acetone in the acetone storage tank.

8. The product extraction device of claim 7, wherein, The shell of the short-path distillation column is made of 316L stainless steel.

9. The product extraction device of claim 4, wherein, The initial condenser tube is a plate heat exchanger; And / or, the medium-temperature section condenser is a shell-and-tube condenser; And / or, the cryogenic section condenser tube is a spiral plate cryogenic condenser.

10. The product extraction device of claim 1 or 2, wherein, The adsorption tower is a two-stage activated carbon adsorption tower.

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