WO2018202604A1

WO2018202604A1 - Apparatus and method for fermentation

Info

Publication number: WO2018202604A1
Application number: PCT/EP2018/061000
Authority: WO
Inventors: Manfred Baldauf; Elvira María FERNÁNDEZ SANCHIS; Katharina Stark; Alexander Tremel
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-05-05
Filing date: 2018-04-30
Publication date: 2018-11-08
Also published as: DE102017207634A1

Abstract

The invention relates to an apparatus and to a method for fermentation, wherein the apparatus comprises a fermenter for receiving a fermentation broth having bacteria, and the fermenter has a cooling apparatus for dissipating the waste heat. The apparatus also comprises a thermal separating apparatus for separating a valuable product out of the fermentation broth, comprising a heat exchanger, and a heat pump. The cooling apparatus is coupled thermally to an evaporator of the heat pump, and the heat exchanger of the thermal separating apparatus is coupled thermally to a condenser of the heat pump. The heating of the thermal separating apparatus is carried out to a great extent or exclusively by means of the waste heat from the fermentation.

Description

description

Device and method for fermentation The invention relates to a device and a method for fermentation.

Demand for electricity fluctuates strongly over the course of the day. Electricity generation also fluctuates with increasing share of electricity from renewable energies during the course of the day. To an oversupply of power at times with a lot of sun and strong winds at low demand for electricity to ausglei ^¬ chen, you need controlled power plants or Spei cher ^¬ to store this energy.

One of the currently envisaged solutions is the conversion of electrical energy into value products, which can serve in particular as platform chemicals. One possible technique for the conversion of electrical energy into useful products represents the electrolysis. In particular, the electrolysis of water into hydrogen and oxygen is one of the tech ^¬ technology known method in the state.

Carbon dioxide is a climate-damaging greenhouse gas. It contributes significantly to the greenhouse effect and thus to global warming. The reduction of the emission of carbon dioxide, especially in industrial processes, is therefore desirable. To possible climate-neutral, meaning xidausstoß low Kohlenstoffdio- operate various industrial Prozes ^¬ se, it is desirable that the carbon dioxide ^¬ that arises in these processes, at least partially convert to recyclables.

The hydrogen which has been produced in an electrolysis can be reacted with climate-damaging carbon dioxide to give an alcohol, in particular ethanol or butanol, a valuable substance. This conversion of carbon dioxide, in particular with the high-energy co-reactant hydrogen, is carried out by specially selected microorganisms, in particular by anaerobic bacteria. Microorganisms can also use carbon monoxide and other high-energy gases as starting materials in order to produce valuable substances from them.

The fermentative conversion of educt gases such as hydrogen, carbon dioxide and / or carbon monoxide is exothermic and usually proceeds at very mild temperatures in a range between 20 ° C and 50 ° C. In order to keep the temperature of this exothermic reaction constant in a fermenter, it is necessary to cool the fermenter. This usually happens with cooling water. The temperature of cooling water depends on the egg ^¬ nen from the collection site, in particular of whether the cooling water is taken from a river, or if it is taken ent ^¬ a closed cooling circuit with the cooling tower and fan for air cooling. The disadvantage is that the temperature of the Kühlwas ^¬ sers is subject to seasonal fluctuations. While in winter in temperate climates usually a cooling water temperature below 15 ° C can be achieved, it is disadvantageously often not possible in the summer. In subtropical or tropical regions, the cooling water temperature often reaches detrimentally above 30 ° C. To be able to ensure a cooling of the fermenter at these temperatures is disadvantageous a large amount of cooling water or active cooling with a chiller necessary.

The gaseous starting materials, in particular carbon dioxide and hydrogen are supplied to the fermenter and to put under free ^¬ reduction of heat to products, especially alcohol, ^¬. Typically, however, only a proportion of 5-10% of desired product is in the fermentation broth. The Fer ^¬ mentationsbrühe is then typically fed into a Rektifikati ^¬ onskolonne to separate the desired product. From ^¬ separation is disadvantageous with high thermal energy consumption.

The object of the invention is to provide a device and a method for fermentation which provide improved energy. has efficiency in terms of cooling and product processing.

The object is achieved with the device according to the invention as claimed in claim 1 and the method according to the invention as claimed in claim 6.

The device according to the invention for fermentation comprises egg ^¬ nen fermenter for receiving a fermentation broth with Bak ^¬ criteria. The fermenter also includes a cooling device for removing the waste heat from the fermentation. The inventive apparatus further comprises a thermal separation apparatus for separating a desired product from the fermentation broth ^¬, wherein the thermal separating device comprises a Wärmetau ^¬ shear which is suitable for supplying heat to the separator. The device also includes a heat pump, where ^{¬ is} thermally coupled to the cooling device with an evaporator of the heat pump and the heat exchanger of the thermal separator is thermally coupled to a condenser of the heat pump. The thermal separation apparatus can be so ^¬ heated by means of the waste heat of fermentation.

In the inventive method, a fermenter containing a fermentation broth with bacteria is first bereitge ^¬ represents. Furthermore, a thermal separation device, which is heated with a heat exchanger, provided. The off ^¬ heat of fermentation is removed by means of a cooling device, wherein the fermenter has an inlet for introducing at least one educt gas and having an outlet for Her ^¬ run the fermentation broth from the fermenter. The cooling device is thermally coupled to an evaporator of a heat pump and the heat exchanger is thermally coupled to a condenser of the heat pump. The thermal separator is heated by the waste heat of the fermentation.

The heat pump significantly raises the energy level of the waste heat. Thus, the thermal separation device can become a major Part or, particularly advantageous, exclusively with ^{¬ means of} the waste heat of the fermentation to be heated, although the waste heat at a low level, in particular between 20 ° C and 50 ° C is obtained. In addition, the cooling ^¬ device is advantageously thermally coupled to the evaporator, so that here a sufficiently large temperature difference between the material flow to be cooled and the cooling device is present. In particular, the temperature difference is at least 10K, more preferably 20K.

Advantageously eliminates a separate evaporator, characterized in that the thermal separation device is heated exclusively via the heat pump, or via the waste heat of the fermenter.

The amount of heat can be removed from the fermentation itself and advantageously brought to a higher temperature level using mechanical or electrical energy

In an advantageous embodiment and development of the invention, the heat pump is an adsorption heat pump or an absorption heat pump. Particularly advantageously, a first and a second working fluid are used in the absorption heat pump, wherein as the first working fluid What ^¬ ser and as the second working fluid, a salt or ammonia is used. Particularly advantageous is the salt lithium bromide or an ionic liquid.

In a further advantageous embodiment and development of the invention, the heat pump is a compression heat pump. The compression heat pump comprises an evaporator for evaporating Ver ^¬ a first working fluid by means of the waste heat of the fermenter. It further comprises a compaction ^¬ ter to compress the first working fluid. The heat pump further comprises a condenser for condensing the first working fluid and at least partially releasing the waste heat to the heat exchanger of the thermal separator. The heat pump further includes an expansion valve for expanding the first working fluid. The compacting of the first working fluid is typically mechanical or electrical.

Advantageously, the first working fluid is fed directly into the cooling ^¬ device, whereby the thermal transition between the fermenter broth and the first working fluid is advantageously very high, and thus the cooling is efficient. The working fluid then transfers the heat in the heat exchanger of the thermal separation device directly to the fermentation broth to be separated, so that an additional heating of the ther ^¬ mix separator is omitted. The entire fermentation process is thus advantageously very energy-efficient.

In a further advantageous embodiment and development of the invention, the heat pump comprises a heat recuperation unit. Depending on the slope of the boiling line of the first working fluid a T-s diagram, an internal heat recuperation can be used. This advantageously increases the efficiency of the heat pump.

As a first working fluid of the compression heat pump ^¬ water, carbon dioxide, ammonia, a hydrocarbon, a fluorocarbon, a Fluorchlorkohlenwas ^¬ hydrogen and / or a fluoroketone used. In particular, fluoroketones have the advantage that they can reach working temperatures of the heat pump of more than 100 ° C., which makes it possible to heat the thermal separation device advantageously at a high energy level.

In a further advantageous embodiment and development of the invention, the thermal separation device comprises at least one rectification column, in particular a Rek ^¬ tification unit, an adsorption unit, a Absorpti ^¬ onseinheit or a membrane separation unit, in particular a membrane distillation or a Thermoosmose. The thermal separator is selected depending on the value product and the biological and thermodynamic properties of the fermentation broth. The thermal separator is advantageously selected such that a heating from the waste heat by means of the heat pump is possible without further heat sources must be used. In an advantageous embodiment and development of

Invention is a first temperature in the fermenter between 20 ° C and 50 ° C, more preferably between 32 ° C and 37 ° C. Particularly preferably, the temperature is in a Be ^¬ rich, in which the bacteria produce the desired product with an optimum efficiency, ie, the temperature is in a temperature range that is optimal for the bacteria. In particular, anaerobic bacteria are used in the fermenter. Preferred are bacteria from the family Clostridiaceae, more preferably Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei or

Clostridium carboxidivorans, Clostridium coskatti used in the fermenter. Furthermore, bacteria of the type

Butyribacterium, especially methylotropicum or type

Acetobacterium, in particular Acetobacterium woodii,

Acetobacterium fimetarium, Butyribacterium methylotrophicum used. Furthermore, co-culture of one or more of the bacteria mentioned can be used in the fermenter.

In a further advantageous embodiment of the invention, the second temperature in the thermal separator is at least 80 ° C. In particular, the tempera ture ^¬ is 80 ° C at least when an alcohol is produced, wel ^¬ cher must be separated from an aqueous solution. Depending on the thermodynamic properties, this temperature is selected. In the case that a Rektifikationsko ^¬ lonne is used, is carried out the laying means well known in process engineering methods, in particular by means of the MESH equations. In an advantageous embodiment and development of

Invention is used as starting gas at least partially carbon dioxide ^¬ . The carbon dioxide and / or further educt gases are converted into a desired product, in particular the product of value comprises alcohol, particularly preferably produ ^¬ the bacteria decorate ethanol or butanol.

Further features, properties and advantages of the present invention will become apparent from the following description with reference to the accompanying figures. In it show schematically:

1 shows a fermenter with a rectification column and a compression heat pump, which thermally couples the fermenter with the rectification column,

2 shows a fermenter with a rectification column and an absorption heat pump, which thermally couples the fermenter with the rectification column.

FIG. 1 shows a device 1 for fermenting. The device 1 comprises a fermenter 2, a rectification column 3 and a compression heat pump 15, which thermally couples the fermenter 2 and the rectification column 3. The Fer ^¬ Menter 2 further comprises a stirring unit 5, which is ^¬ driven by means of a motor 4. As an alternative to a classical stirrer is in industrially employed fermenter tern an airlift principle or a jet principle used for mixing and aerating the fermentation broth. The circulation of the ingredients is carried out exclusively by the injection of gases, in particular carbon dioxide, hydrogen and / or carbon monoxide. Advantageously, there are no moving parts, which makes these mixers low maintenance.

A cooling device 6 of the fermenter 2 is at the same time the evaporator of the compression heat pump 15 in this first exemplary embodiment. The working fluid AFI of the heat pump is used here as the coolant. The heat is advantageously removed with ^¬ directly from the fermenter 2 and PE in the Wärmepum 15 transferred. The working fluid AFI of the heat pump is Accordingly, evaporated in the cooling device 6 of the fermenter 2 by means of the energy of the waste heat of the fermenter 2. In a dense Ver ^¬ 8, the working fluid is compressed AFI. Subsequently, the working fluid AFI is guided into a heat exchanger 9. The thermal separator 3 comprises the heat exchanger 9. The heat exchanger 9 is supplied with the working fluid AFI of the heat pump 15 as the heat source. The heat exchanger serves as equal to ^¬ capacitor of the heat pump 15. The working fluid AFI condenses in the heat exchanger 9 and transfers the heat to the bottom stream, ie the stream leaving the rectification column 3 at the foot, and is then at least partially ^¬ in the rectification column 3 zurückge ^¬ leads. In this embodiment, the Sumpfström comprises in particular water. A portion of the bottoms stream is passed through a second heat exchanger 10 where it, preheats the fermentati ^¬ onsbrühe FB with the desired product, which ver can ^¬ the fermenter 2 before the fermentation broth FB is fed into the Rek ^¬ tifikationskolonne. 3 The working fluid AFI of the heat pump 15 is then passed through an expansion valve 7, in particular through a throttle, and there expan ^¬ diert. The working fluid AFI is then fed back to the evaporator or the cooling device 6 of the fermenter 2.

As a working fluid AFI for the compression heat pump 15 struc- NEN conventional working fluids, since the lifting of the Ener ^¬ gieniveaus from a temperature range between 32 ° C and 37 ° C to at least 80 ° C by means of conventional working fluids, in particular by means of water, carbon dioxide, ammonia , Hydrocarbons, in particular propane, butane or propene, by means of fluorocarbons or chlorofluorocarbons. In the event that 3 temperatures above 100 ° C are required in the rectification ^¬ lonne to separate a product, in particular fluoroketones are suitable as the working fluid AFI. Advantageously, fluoroketones allow the temperature level to be raised above 100 ° C. At the top of the rectification column 3, the product, in particular the alcohol, is recovered. FIG. 2 shows a device with a fermenter 2 of a rectification column 3 and an absorption heat pump 25. The fermenter 2 further comprises a motor 4, which drives a stirring unit 5. In the fermenter 2 is located, as in the first embodiment, a fermentation broth FB with bacteria. The fermentation broth FB comprises typi ^¬ shear, water, nutrients, especially metals and mining ^¬ ralsalze, in particular calcium chloride, sodium chloride, Mag ^¬ nesiumchlorid, potassium chloride and phosphoric acid, furthermore trace elements, in particular metal ions as cofactors, such as nickel, zinc, iron, selenates and continue vitamins, ammo ^¬ niumchlorid and / or folic acid. Into the fermenter 2 is we ^¬ nigstens a feed gas E, in particular carbon dioxide and hydrogen carried out. The bacteria, which are present in the fermenter 2 in the fermentation broth FB, set the

Feedstock gases E to alcohol as value product P um. Most are 5% to 10% alcohol in the fermentation broth FB, ^¬ so that the alcohol must be separated by distillation in a thermal separator 3. In order to keep the temperature in the fermenter 2 constant, it is necessary to cool it. Cooling takes place at a low temperature level of 20-50 ° C.

The cooling device of the fermenter 2 is energetically gekop- pelt with an evaporator of the absorption heat pump 25. Be ^¬ Sonders advantageously a first working fluid AFI is guided through the cooling device 6 of the fermenter 2, and there evaporated ^¬ di rectly. The vaporous first working fluid AFI is then passed into an absorber 11, where it is absorbed while releasing heat into a second working fluid AF2.

The heat given here must with cooling water discharged ^¬ to maintain a constant temperature in the absorber to be granted slightest ^¬ th. The second working fluid AF2, which is now loaded with the first working fluid ^¬ AFI is then pumped using a complementary and ^¬ telpumpe 20 in the expeller 12 and thereby raised to a higher pressure level. The required electrical power tion for the solvent pump 12 is significantly lower than that of a gas compressor due to the incompatibility of the liquid. In the expeller 12, the first working fluid AFI is separated from the second working fluid AF2. The required for thermal energy at a higher Temperaturni ^¬ veau is provided ^¬ by means of a heat supply 21, for example, by firing with fuel, in particular natural gas. In this context, a Ready Stel ^¬ development of heat by burning biomass would be possible, which is formed during the fermentation process. The regene ^¬ tured second working fluid AF2 is then recycled to the absorber 11 via a pressure regulating ^¬ duzierventil. The first Ar ^¬ beitsfluid AFI is guided into a heat exchanger. 9 The heat of condensation is transferred to the bottom stream, which is passed from the rectification column 3, so that the bottoms stream from the rectification column 3 is warmed up and at least partially fed back into the rectification column 3. Another part of the bottoms stream is then in heat exchanger 10 by means of the waste heat of the me Fermentationswär- FB again heated and at least partially recycled to the recti ^¬ fikationskolonne. 3 The product P is recovered at the top of the rectification column 3. The compression in ei ^{¬ an} absorption ^heat pump is also referred to as thermal compaction ^¬ tion.

Claims

claims

Claims 1. Apparatus (1) for fermentation, comprising:

a fermenter (2) for receiving a fermentation broth (FB) with bacteria and with a cooling device (6) for removing the waste heat from the fermentation,

- a thermal cutting device (3) for separating a valuable product (P) from the fermentation broth with a heat exchanger ^¬ (9)

a heat pump (15, 16),

wherein the cooling device (6) is thermally coupled to an evaporator of the heat pump (15, 16) and the heat exchanger (9) is thermally coupled to a condenser of the heat pump (15, 16) for heating the thermal separator (3) by means of the waste heat Fermentation.

2. Device according to claim 1, wherein the heat pump is an absorption heat pump (16) or an adsorption heat pump.

3. A device according to claim 1, wherein the heat pump is a compression heat pump (15).

4. The apparatus of claim 3, wherein the compression heat pump system comprises:

the evaporator for evaporating a first working fluid (AFI) by means of the waste heat of the fermenter (2),

a compressor (8) for compressing the first working fluid (AFI),

the condenser, for condensing the first working fluid (AFI) and at least partially releasing the waste heat to the heat exchanger (9),

- An expansion valve (7) for expanding the first working fluid (AFI).

5. Device according to one of the preceding claims, wherein the thermal separation device (3) comprises at least one rectification ^¬ cation column, an adsorption unit, an absorption unit ^{¬ unit} or a membrane separation unit.

6. Method for fermenting with the following steps:

- providing a fermenter (2) having a fermentation broth ^¬ (FB) with bacteria,

Providing a thermal separation device (3) which is heated by a heat exchanger (15, 16),

Removing the waste heat of the fermentation by means of a cooling device (6), the fermenter (2) having an inlet for introducing at least one educt gas (E) and having an outlet for removing the fermentation broth (FB) from the fermenter (2),

wherein the cooling device (6) is thermally coupled to an evaporator of a heat pump (15,16) and the Wärmetau ^¬ shear (9) is thermally coupled to a capacitor and the thermal separation device (3) is heated by the waste heat of the fermentation.

7. The method according to claim 6, wherein a heat pump Ad ^¬ sorption heat pump or absorption heat pump (16) verwen ^¬ det is.

8. The method according to claim 7, wherein as a second working fluid (AF2) of the absorption heat pump, an ionic liquid ^¬ speed is used.

9. The method of claim 6, wherein a Comp ^¬ ressions heat pump (15) is used as a heat pump.

10. The method of claim 9, wherein as a first working fluid (AFI) of the compression heat pump water, carbon ^¬ dioxide, ammonia, a hydrocarbon, a Fluorkohlenwas ^¬ serstoff, fluorine chlorinated hydrocarbon and / or fluorine is used ketone.

11. The method according to any one of claims 6 to 10, wherein a first temperature (Tl) in the fermenter (2) in a range between 20 ° C and 50 ° C.

12. The method of claim 11, wherein the first temperature (Tl) is in a range between 32 ° C and 37 ° C.

13. The method according to any one of claims 6 to 12, wherein a second temperature (T2) in the thermal separating device (3) is at least 80 ° C.

14. The method according to any one of claims 6 to 13, wherein as the reactant gas at least partially carbon dioxide is used.

15. The method of claim 14, wherein the bacteria convert the reactant gas (E) into a useful product (P), which we ^¬ nigstens comprises an alcohol.