High-energy-efficient production process

Abstract

The present invention relates to a process for reusing heat in a protein culture, the process comprising aerobically fermenting a material with a thermophilic organism to provide a thermophilic fermentation culture; and performing a drying process on the thermophilic fermentation culture using heat generated during aerobic fermentation. The present invention further relates to a system for reusing heat in a protein culture.

Description

Technical Field

[0001] The present invention relates to a highly energy-efficient production process, particularly a process for reusing heat in protein cultures. Further, the present invention relates to a heat reuse system in protein cultures.

Background Art

[0002] With the increase in the world population, the demand for high-protein foods such as meat, dairy products, insects, and fish is rapidly increasing. One way to produce high-protein animal feed is to produce single-cell protein (SCP) by a biosynthetic process such as fermentation.

[0003] Such biosynthetic processes are powered by conventional energy sources such as fossil fuels. Fossil fuels are non-renewable resources because they take millions of years to form. Further, the use of fossil fuels is causing serious environmental problems. Renewable energy sources such as biomass and sunlight are promising alternatives to many conventional energy sources. However, the scaling up of such renewable energy sources is causing problems of energy demand and production cost.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the present invention is to address these problems in the production of single-cell protein.

Means for Solving the Problems

[0005] According to one embodiment, the present application provides a process for the reuse of heat in a protein culture, the process comprising aerobically fermenting a material with a thermophilic organism to obtain a thermophilic fermentation culture; and performing a drying process on the thermophilic fermentation culture using the heat generated during aerobic fermentation. Thereby, additional energy is provided in the drying process, reducing or minimizing the external energy consumption for performing the drying process. As a result, by reusing energy, the efficiency of the entire process is improved and the overall energy consumption is reduced, thereby addressing the issue of climate change and restricting the use of fossil fuel resources. Further, since the heat or a part of the heat generated during fermentation is reused, the heat discharged to the environment is reduced. Thereby, as part of avoiding the use of a cooling system, heat pollution can be significantly reduced.

[0006] According to one embodiment, the process further comprises using a first heat exchanger to capture the heat generated during the aerobic fermentation process and heating an air stream for the drying process. The heat exchanger avoids any form of combustion heating, thereby reducing or eliminating contamination and risks due to carbon monoxide and / or carbon dioxide poisoning.

[0007] According to one embodiment of the present invention, the first heat exchanger is a heat pump. By using a heat pump, they consume little or no fuel other than the electricity required to operate the pump, thereby emitting little or no carbon and reducing the carbon footprint. As a result, greenhouse gas emissions can be reduced. Optionally, the heat pump uses ammonia or R1234 as a refrigerant.

[0008] According to one embodiment, this process further includes using a second heat exchanger to increase the temperature of the air flow flowing out of the first heat exchanger. By further using the second heat exchanger, the temperature of the air flow used in the drying process can be increased above 100°C. Optionally, the second heat exchanger is a steam type heat exchanger. Optionally, the second heat exchanger includes one or more steam type heat exchangers and one or more heat pumps.

[0009] According to one embodiment, the capture of heat generated during aerobic fermentation includes the capture of heat from the gas flow discharged during fermentation. By using the heat generated during aerobic fermentation, an additional energy source for heating the air flow used in the drying process is avoided. Optionally, the gas flow has a temperature of 36°C or higher. Preferably, the gas flow has a temperature of 38°C or higher. More preferably, the gas flow has a temperature of 46°C to 54°C. Optionally, the gas flow has a relative humidity of 100%.

[0010] According to one embodiment, the heated air flow used during drying has a temperature of 70°C or higher, such as 75°C, 80°C, 90°C, or 100°C or 120°C. This temperature of 70°C or higher ensures that the fermentation culture dries under the conditions required to obtain a protein culture. Using the temperature of the air flow during drying between 70°C and 90°C is more optimal than using a temperature of 100°C in terms of obtaining a protein culture.

[0011] According to one embodiment, the drying process includes, in a first step, drying the thermophilic fermentation culture using a heated air stream, and, in a second step, drying the thermophilic fermentation culture using the heat generated during the first step of drying. By using a multi-stage drying process, the exhaust air of the dryer is reheated and reused in the next drying step, reducing the energy required to heat the air stream because the drying can be carried out in several steps, each step using a different drying temperature. This supplies additional energy to the drying process, resulting in a reduction or minimization of the external energy consumption for carrying out the drying process.

[0012] According to one embodiment, utilizing the heat generated during the first drying step includes using a third heat exchanger to capture heat from a first air stream discharged during the first drying step and heating a second air stream. Optionally, the third heat exchanger is a heat pump.

[0013] According to one embodiment, this process further utilizes the heat generated during aerobic fermentation in a clean in-process (CIP).

[0014] According to one embodiment, sterile air is introduced during aerobic fermentation. By introducing sterile air, the invasion of foreign fungal spores or yeast can be prevented. Optionally, the sterile air is introduced at a predetermined air flow rate. By introducing air at a predetermined flow rate, it is ensured that the fermentation continues without stopping. Optionally, the predetermined air flow rate is 0.5 to 2.0 liquid volumes per minute (vvm).

[0015] According to one embodiment, at least one substance is introduced during aerobic fermentation to control the pH during fermentation. The at least one substance is, for example, ammonia (NH3), sulfuric acid (H2SO4), phosphoric acid (H3PO4), NaOH, nitrous acid hydrate (H2NO3), and nitrogen source ammonium phosphate ((NH4)3PO4), diammonium sulfate (NH4)2SO4), urea (CH4N2O), etc.

[0016] According to one embodiment, the present application provides a system for the reuse of heat in a protein culture, the system comprising: a fermenter configured to aerobically ferment a thermophilic organism and a material to provide a thermophilic fermentation culture, and configured to discharge a gas stream from the fermenter; a dryer configured to dry the thermophilic fermentation culture to recover the protein culture; and a heat exchange system configured to capture heat from the exhaust gas stream of the fermenter and use the captured heat to supply a high-temperature gas stream to the dryer.

[0017] According to one embodiment, the fermenter includes an air inlet through which sterile air can be introduced. Optionally, the sterile air is introduced at a predetermined air flow rate.

[0018] According to one embodiment, the fermenter includes a second air inlet through which at least one substance for controlling pH can be introduced. Optionally, the air inlet through which sterile air is introduced and the second air inlet through which at least one substance is introduced can be the same air inlet.

[0019] According to one embodiment, the system further includes a second heat exchanger configured to further increase the temperature of the heated air stream used in the dryer. Optionally, the second heat exchanger is a steam heat exchanger. Optionally, the second heat exchanger is one or more steam heat exchangers and one or more heat pumps.

[0020] According to one embodiment, the system further includes: a first dryer configured to dry the thermophilic fermentation culture using the heated air stream; a third heat exchanger configured to capture heat from the first air stream discharged from the first dryer and use the captured heat to provide a second heated air stream; and a second dryer configured to dry the thermophilic fermentation culture using the second air stream to recover the protein culture. Optionally, the third heat exchanger is a heat pump.

[0021] According to one embodiment, the system further includes a condenser that heats process water, wash water, or the buildings of an office or a brewery.

[0022] According to one embodiment, the system further includes a CIP system configured to use the heat generated during aerobic fermentation.

[0023] The present invention will be further described with respect to the embodiments shown in the drawings.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0025] The following is a description of specific embodiments of the present invention, given solely by way of example and with reference to the figures. It should also be understood that the terms used herein are for the sole purpose of describing particular aspects and are not intended to be limiting.

[0026] FIG. 1 is a flowchart showing a process 100 for reusing heat in a protein culture according to an embodiment.

[0027] In an initial step 120, process 100 includes aerobically fermenting a material with a thermophilic organism to provide a thermophilic fermentation culture.

[0028] The thermophilic organisms used in the present invention refer to organisms that grow at least at 36, 37, 38, 39, 40, 45, 50 or 55 °C, and in some cases even at temperatures higher than 65 °C. The thermophilic organisms used further refer to organisms that also grow at a low pH, for example a pH of 4.4 or less. The thermophilic organisms used further refer to organisms that can obtain biomass with a high protein content. The material used is a feedstock that can function as a carbon source and an energy source for the thermophilic organism.

[0029] Fermentation is understood in this context as the conversion of a material (e.g., a feedstock) using an organism (e.g., a thermophilic organism) into a product (e.g., a protein culture). During fermentation, gases such as CO2, water, and heat are also generated. Traditionally, fermentation is of two types: aerobic fermentation that requires oxygen and anaerobic fermentation that does not require oxygen.

[0030] Optionally, process 100 may include introducing air during fermentation. The air introduced during fermentation may contain oxygen at a concentration exceeding 0.2 mg / L to optimize the growth conditions. Optionally, the oxygen concentration may be more than 0.5 mg / L, or more than 1 mg / L, or more than 2 mg / L. Optionally, the air can be introduced at a predetermined air flow rate. For example, the predetermined air flow rate is 0.5 - 2.0 liquid volumes per minute (vvm). For example, 0.5 vvm, 1 vvm, 1.5 vvm or 2.0 vvm. The measurement unit "vvm" is calculated by dividing the measured air flow rate (L / m) by the volume (L) of the growth medium (including the cultured cells). Alternatively, the air can also be introduced at a variable air flow rate that may depend on the fermentation conditions. Optionally, the air introduced during fermentation can be sterilized or non-sterilized. Sterilization of the air can help prevent the invasion of fungal spores, yeasts and bacteria into the fermentation.

[0031] Optionally, process 100 may include introducing at least one substance to control the pH during fermentation. The at least one substance is, for example, ammonia (NH3), sulfuric acid (H2SO4), phosphoric acid (H3PO4), NaOH, nitrous acid hydrate (H2NO3), and nitrogen source ammonium phosphate ((NH4)3PO4), diammonium sulfate (NH4)2SO4), urea (CH4N2O), etc.

[0032] As shown in FIG. 1, in step 120, process 100 includes performing a drying process on the thermophilic fermentation culture using the heat generated during aerobic fermentation.

[0033] During drying, the moisture content of the thermophilic fermentation culture is reduced to obtain a protein culture by the application of heat via a warm air stream. Since aerobic fermentation generates a large amount of heat (in contrast to anaerobic fermentation, which generates much less heat due to the absence of an air flow), the heat generated during aerobic fermentation can be used to heat the air stream for use in the drying process without an additional energy source. In the case of anaerobic fermentation, usually an additional energy source is required to power the dryer, resulting in higher costs and being less environmentally friendly.

[0034] Optionally, process 100 includes using a first heat exchanger to capture the heat generated during the aerobic fermentation process and heating the air stream for the drying process. For example, the temperature of the heated air stream is 70°C or more and 100°C or less, which may correspond to the temperature required for the drying process. As another example, the temperature of the heated air stream is 50°C, which may be lower than the temperature required for the drying process.

[0035] In the context of the present application, "heat exchanger" means any device useful for transferring heat from one medium to another. These mediums can be gases, liquids, or a combination of both. Different types of heat exchangers, such as heat pumps, heat pipe heat exchangers, steam heat exchangers, heat transfer heat exchangers, etc., can be used. Preferably, the heat exchanger is a heat pump and / or a steam heat exchanger. Using a steam heat exchanger instead of a heat pump makes it cheaper to achieve a temperature rise above 100°C.

[0036] A heat pump may include an evaporator, a compressor, a condenser, and an expansion device. The refrigerant circulating at low pressure in the evaporator captures heat from the warm air flowing through the evaporator. When the refrigerant absorbs heat, it changes from a liquid state to a vapor state. The vapor-state refrigerant is compressed to high pressure in the compressor. By compressing the refrigerant, the pressure and temperature of the refrigerant increase. The refrigerant then circulates through a condenser where a cold air flow colder than the normal refrigerant flows. The air flow captures heat from the refrigerant, and as a result, the refrigerant condenses. When the refrigerant releases heat, it returns from a vapor state to a liquid state. Thereafter, the liquid-state refrigerant becomes low pressure from high pressure in the expansion device. The refrigerant flows back to the evaporator and the cycle resumes.

[0037] Generally used refrigerants are natural refrigerants or synthetic refrigerants. Examples of natural refrigerants include ammonia, carbon dioxide (CO2), hydrocarbons (such as butane, isobutane, etc.), water, and air. Examples of synthetic refrigerants are (hydro)chlorofluorocarbons ((H)CFC), hydrofluorocarbons (HFC), and hydrofluoroolefins (HFO). Optionally, the refrigerant is ammonia. Ammonia has excellent thermodynamic properties, a high heat transfer coefficient, and does not contribute to the greenhouse effect. Furthermore, although ammonia is flammable and toxic, due to its strong odor, leaks can be detected quickly. Alternatively, the refrigerant is R1234. R1234 is a hydrofluoroolefin refrigerant that does not contribute to the greenhouse effect. R1234 is inefficient but is non-flammable or slightly flammable. Therefore, R1234 shows a lower cost inversion compared to ammonia, which may require additional safety costs due to its toxicity.

[0038] The efficiency of a heat pump is expressed as the coefficient of performance (COP). The COP is defined as the ratio of the rate at which the heat pump transfers thermal energy (in kW) to the amount of electrical energy required for pumping (in kW). For example, if a heat pump uses 1 kW of electrical energy to transfer 3 kW of heat, the COP is 3. The higher the COP, the higher the efficiency of the heat pump and the less energy it consumes.

[0039] A steam heat exchanger may include a shell surrounding a tube or a bundle of tubes. The steam heat exchanger utilizes steam that enters the shell through an opening and surrounds the tubes within the shell. When the latent heat of the steam is transferred to the medium (e.g., an air stream) inside the tubes, the temperature of the medium rises and the steam condenses. Next, the condensed water is collected at the bottom of the shell and discharged towards the condensate outlet. A steam trap is installed at the condensate outlet. The function of the steam trap is to hold the steam inside the shell until the latent heat is transferred and then discharge the condensed water.

[0040] Optionally, a cleaning substance (e.g., water) can capture the heat generated during fermentation and be used in a clean-in-place (CIP) process. CIP is a process of cleaning the inner surfaces of containers such as pipes, fermenters, vessels, condensers, and filters by circulating a cleaning substance to wash and rinse the inner surfaces without disassembling them. Usually, a final warm water rinse is performed to sterilize the inner surfaces. By using the heat generated during fermentation in the CIP process to raise the temperature of the cleaning substance, external energy for heating the cleaning substance becomes unnecessary or almost unnecessary, making the entire process more efficient. Optionally, water can capture the heat generated during fermentation and be used in other processes such as building heating, cleaning water processes, etc., which require water heated above 45°C, or above 60°C and below 85°C.

[0041] Optionally, process 100 includes raising the temperature of the heated air stream by using a second heat exchanger. If the temperature of the air stream after being heated by the heat exchanger is lower than the temperature required for the drying process, the second heat exchanger can be used to further raise the temperature to the temperature required for the drying process. For example, if the temperature of the heated air stream after passing through the first heat exchanger is lower than the temperature required for the drying process, e.g., 50°C, the temperature can be further raised to, e.g., 70°C, 100°C or 120°C using the second heat exchanger. Optionally, the second heat exchanger is a steam heat exchanger. Optionally, the second heat exchanger is one or more steam heat exchangers and one or more heat pumps.

[0042] Optionally, the drying process is a multi-stage drying process. In the first step of the multi-stage drying process, the heated air stream heated by the first heat exchanger (e.g., the first heat pump) using the heat generated during aerobic fermentation is used for drying the thermophilic fermentation culture. In the second step, the temperature of the air stream discharged during the first step of the drying process is raised using a second heat exchanger (e.g., a steam heat exchanger), and the heat of this heated air stream is used for drying the thermophilic fermentation culture.

[0043] Optionally, the first heat pump of process 100 may include another condenser for raising the temperature of the process water. The process water can be used for other processes such as building heating and washing water processes that capture the heat generated during fermentation and require water heated above 45°C, or above 60°C and below 85°C.

[0044] Hereinafter, for convenience, FIGS. 2-4 are described as if the first heat exchanger is a heat pump and the second heat exchanger, if present, is a steam heat exchanger. However, those skilled in the art will understand that any other heat exchanger can be used without departing from the scope of the present invention.

[0045] Figure 2 shows a schematic diagram of a system 200 for reusing heat in a protein culture. The system 200 includes a fermenter 210, a first heat exchanger 220, and a dryer 230.

[0046] In the context of this application, "fermenter" means any device useful for growing organisms (such as yeast, fungi, bacteria, or animal cells) under controlled conditions. The fermenter in which the processes described herein are carried out can be any type of fermenter known in the art, preferably a fermenter suitable for aerobic fermentation. Advantageously, the fermenter is a simple bubble column, which can operate on a very large scale, for example >100m 3 >500m 3 >1000m 3 >2000m 3 >3000m 3 or >4000m 3 etc., thereby reducing the number of fermenters per factory, the total investment, and the operating costs.

[0047] In this context, "dryer" means any device useful for reducing the moisture content of particulate matter by the application of direct or indirect heat, including but not limited to fluidized bed dryers, vibrating fluidized bed dryers, fixed bed dryers, traveling bed dryers, belt dryers, cascade rotary bed dryers, long slot dryers, hopper dryers, or kilns. Such dryers can also consist of a single or multiple vessels, single or multiple stages, be stackable or non-stackable, and may include internal or external heat exchangers.

[0048] The fermenter 210 includes at least one inlet 211 and at least one outlet 212. The fermenter may include more components, such as sensors.

[0049] Thermophilic organisms are supplied to the fermenter so that aerobic fermentation of the material occurs. For aerobic fermentation, a sterile air stream is introduced into the fermenter 210 through the inlet 211.

[0050] During aerobic fermentation, the gas stream is discharged from the fermenter 210 through the outlet 212. Since thermophilic organisms are used for fermentation, the fermenter 210 can operate without an internal cooling system, and internal cooling coils in the fermenter, baffles of the stirred fermenter or cooling coils in the fermenter wall, Riesel cooling or cooling towers are not required. An external cooling loop using a heat exchanger is also not required. This reduces the required investment because cooling is performed by evaporation of water, and the water exits the fermenter through the outlet 212 via the gas stream exhaust port of the fermenter 210. Optionally, an external cooling jacket can be wound around the fermenter to assist in maintaining the temperature during aerobic fermentation.

[0051] Preferably, the gas stream has a relative humidity of 100%. A relative humidity of 100% indicates that the gas is completely saturated with water vapor and cannot hold any more. Preferably, the temperature of the gas stream is 36°C or higher. More preferably, it is between 36°C and 65°C. Even more preferably, the gas stream has a temperature between 46°C and 50°C.

[0052] The first heat exchanger 220 of the system 200 is a heat pump 220 including an evaporator 221, a compressor 222, a condenser 223, and an expansion device 224.

[0053] The gas stream discharged from the fermenter 210 through the outlet 212 flows through the evaporator 221 that captures heat from the gas stream and heats the refrigerant. The heat absorbed by the refrigerant is then captured by the air stream flowing into the condenser 223, and as a result, the air stream is heated.

[0054] The heated air stream then flows through the dryer 230 so that a protein culture can be obtained from the fermentation culture.

[0055] Figure 3 shows a schematic diagram of the system 200 for reusing heat in the protein culture, where the system 200 further includes a second heat exchanger 240.

[0056] During aerobic fermentation, the gas stream is discharged from the fermenter 210 through the outlet 212. The first heat exchanger 220 of the system 200 is a heat pump 220 including an evaporator 221, a compressor 222, a condenser 223, and an expansion device 224. The gas stream discharged from the fermenter 210 through the outlet 212 flows through the evaporator 221 that captures the heat from the gas stream and heats the refrigerant. The heat absorbed by the refrigerant is then captured by the air stream flowing into the condenser 223, resulting in the heating of the air stream.

[0057] The temperature of the heated air stream after flowing through the first heat exchanger 220, for example 50°C, is lower than the temperature required for the drying process, for example 70°C. Therefore, a second heat exchanger 240 (for example, a steam heat exchanger) is used to further increase the temperature to, for example, 120°C. Then, the heated air is flowed into the dryer 230 so that a protein culture can be obtained from the fermentation culture.

[0058] Figure 4 is a schematic diagram of the system 200 that reuses the heat of protein culture, and this system 200 further includes an additional condenser 250 in the first heat exchanger 220.

[0059] By using the additional condenser 250, the water stream can capture the heat generated during fermentation. The water stream circulates through the additional condenser 250 so that the temperature of the water stream rises from, for example, 15°C to 50°C. The heated water stream can be used for other processes such as building heating, washing water process, etc.

[0060] FIG. 5 shows a schematic diagram of a drying process using a dryer. The dryer can be the dryer 230 of FIGS. 2-4. In FIG. 5, the dryer 230 includes a first dryer 231 and a second dryer 232. The first dryer and the second dryer can be referred to as a first drying chamber and a second drying chamber, respectively. Optionally, the dryer 230 may include more than two dryers. In a first step of the drying process, the thermophilic fermentation culture is dried using an air stream heated by the first heat exchanger 220 and, if present, the second heat exchanger 240. During the first step of the drying process, a first air stream is discharged from the first dryer 231. A heat exchanger 260 (e.g., a heat pump 260) captures heat from the first air stream and is used to heat a second air stream. In a second step of the drying process, the thermophilic fermentation culture is further dried using the second air stream. Further, the drying process may include more than two steps, and as a result, each step may use a heat exchanger (such as the heat exchanger 260) to capture heat from the air stream discharged from the previous dryer and heat an air stream for further drying the thermophilic fermentation culture.

[0061] As described, the heat generated during aerobic fermentation is used to heat an air stream for drying the aerobic fermentation culture. By using this heat, additional energy sources such as those derived from fossil fuel sources are avoided. As a result, the present invention provides a more environmentally friendly process and system for obtaining a protein culture from aerobic fermentation. Further, the heat generated during aerobic fermentation is so excessive that it is sufficient to heat the air stream used during drying, so that even in a side process such as a CIP process, this heat generation during aerobic fermentation can be utilized, and a portion of the generated heat can be further used to heat the cleaning substance in the CIP process, thereby reducing or even avoiding further use of an additional energy source.

[0062] The present invention has been described as drying (thermal drying) the fermented culture after fermentation using a heated air stream. However, since thermal drying (or thermal dehydration) is more expensive than mechanical drying (or mechanical dehydration) in terms of energy cost, the drying step is optionally carried out in two steps: a first step of mechanical drying and a second step of thermal drying.

[0063] In the first step, after fermentation, at least one of sieving, filtration, decantation, and decanter centrifugation is used to dry the thermophilic fermented culture so that the dry matter concentration of the thermophilic fermented culture becomes at least 8%, 10%, 12% by weight. Optionally, the fermented culture can be pasteurized. By pasteurization, the thermophilic organisms present in the fermented culture are thermally inactivated (or simply inactivated), the shelf life of the fermented culture can be extended, and harmful microorganisms in the fermented culture can be killed without affecting the nutritional value. Then, the concentrated and optionally pasteurized fermented culture is dried by squeezing out the residual moisture using compressed air, such as an air press, and / or mechanical pressing, such as a filter press, a belt press, or a screw press, to obtain biomass (cake). As a result, the dry matter concentration of the fermented culture is at least 20%, 25%, 30%, 35%, 40%, 45%, 50% by weight. Optionally, the water fraction obtained after sieving, filtering, decanting, centrifuging, and / or pressing the fermented culture is reused for fermentation and / or used in a further fermentation batch.

[0064] After squeezing the fermentation culture into a cake, optionally, the cake can be crushed or extruded to allow, for example, drying, preferably air-drying. Preferably, to enable (more efficient) drying of the cake, the particle size of the cake is reduced by physical means. This can optionally be done by extruding the cake through holes with diameters of 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2, 3, 4, 5, 6, 7, 8, 9 mm or 10 mm using an extruder known per se in the art. However, if the dry matter concentration of the cake after pressing is very high and extrusion of the cake is no longer possible (for example, if the cake is too hard to extrude), the particle size of the cake can be reduced by a combination of grinding and sieving. As the grinding step, any type of grinder known per se in the art, such as a knife mill or a hammer mill, etc., can be used. To obtain a homogeneous particle size of the ground cake, larger particles still present after grinding can be removed before drying by a sieve having a pore diameter of 0.5, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 3, 4, 5, 6, 7, 8, 9, or 10 mm. The resulting ground cake will preferably have a particle size of 1 to 9 mm before drying, more preferably 8 mm before drying. By reducing the particle size, the evaporation of moisture from the cake becomes more efficient and faster.

[0065] In a second step, the heat generated during aerobic fermentation is utilized to dry the pressed fermentation culture (or cake). The hot air can dry the cake in a gentle and cost-effective manner, for example, in a belt dryer or a fluidized bed dryer.

[0066] Figure 6 shows an exemplary representation of a drying process using a horizontal fluidized bed dryer. The dryer can be the dryer 230 of FIGS. 2 - 4. In FIG. 6, the dryer 230 is a horizontal fluidized bed dryer. The dryer 230 includes a first dryer 231, a second dryer 232, a third dryer 233, and a fourth dryer 234. The pressed fermentation culture (or cake) is continuously supplied from the inlet of the first drying chamber 231 and dried while moving horizontally on the grid 280 to the outlet 234a of the fourth drying chamber 234. Through the grid 280, a heated air stream is blown upward into the corresponding drying chamber via the inlet. The cake that moves horizontally continuously from the first dryer 231 to the fourth dryer 234 is generally known as the bed 290.

[0067] Each drying chamber includes an outlet through which the air stream is discharged from the drying chamber. The discharged air stream can be the first air stream of FIG. 5. A heat exchanger (e.g., the heat pump 260 of FIG. 5) captures heat from the first air stream and heats a second air stream that is blown upward into the next drying chamber. The heated air stream can be the second air stream of FIG. 5.

[0068] During drying, bubbles are formed in the bed 290. Bubbles in a fluidized bed are generally beneficial as they promote solid mixing, heat transfer, and mass transfer. However, bubbles tend to coalesce and move towards the center of the dryer. Baffles 270 are arranged between each dryer to improve the bubble distribution across the bed cross-section. Various types of baffles can be used, such as wire meshes, perforated plates, turn plates, louver plates, rings. During drying, agglomeration and deposition near the baffles can prevent uniform bed fluidization and cause local overheating of the cake. Therefore, by vibrating the bed, the velocity of the particles in the bed can be limited. Vibration limits agglomeration and deposition near the baffles.

[0069] In this document and in its claims, the verb "comprise" and its conjugations are used in a non-limiting sense, meaning that the items following the word include the items mentioned, but do not exclude items not specifically mentioned. Further, the reference to an element by the indefinite article "a" or "an" does not exclude the possibility that there may be more than one element, unless the context clearly requires that there be only one element. Thus, the indefinite article "a" or "an" usually means "at least one".

[0070] From the above, the present invention can be summarized by the following embodiments:

[0071] Embodiment 1. A process (100) for recycling heat in a protein culture, comprising the step of aerobically fermenting a material with a thermophilic organism to provide a thermophilic fermentation culture (110), and the step of performing a drying process on the thermophilic fermentation culture using the heat generated during aerobic fermentation (120).

[0072] Embodiment 2. The process according to Embodiment 1, comprising using a first heat exchanger to capture the heat generated during the aerobic fermentation process and heating an air stream for the drying process.

[0073] Embodiment 3. The process according to Embodiment 2, wherein the first heat exchanger is a heat pump.

[0074] Embodiment 4. The process according to Embodiment 3, wherein the first heat pump uses ammonia or R1234 as a refrigerant.

[0075] Embodiment 5. The process according to Embodiments 2 to 3, wherein capturing the heat generated during fermentation includes capturing heat from a gas stream discharged during fermentation, and the gas stream has a temperature of 36°C or higher and a relative humidity of 100%.

[0076] Embodiment 6. The process according to any one of Embodiments 2 to 5, wherein the drying process further includes raising the temperature of the air flow flowing out from the first heat exchanger using the second heat exchanger.

[0077] Embodiment 7. The process according to Embodiment 6, wherein the second heat exchanger is a steam type heat exchanger.

[0078] Embodiment 8. The process according to any one of Embodiments 2 to 7, wherein the heated air flow used during drying has a temperature between 70°C and 120°C.

[0079] Embodiment 9. The process according to any one of Embodiments 2 to 8, wherein the drying process includes, in a first step, drying the thermophilic fermentation culture using the heated air flow, and in a second step, drying the thermophilic fermentation culture using the heat generated during the first drying step.

[0080] Embodiment 10. The process according to Embodiment 9, wherein using the heat generated during the first drying step includes capturing heat from the first air flow discharged during the first drying step using a third heat exchanger and heating a second air flow.

[0081] Embodiment 11. The process according to Embodiment 10, wherein the third heat exchanger is a heat pump.

[0082] Embodiment 12. The process according to any one of the preceding embodiments, further including using the waste heat generated during aerobic fermentation in a clean in - process (CIP).

[0083] Embodiment 13. The process according to any one of the preceding embodiments, wherein aerobically fermenting the material with a thermophilic organism to provide a thermophilic fermentation culture includes introducing sterile air or non - sterile air.

[0084] Embodiment 14. The process according to Embodiment 13, wherein the sterile air or non - sterile air is introduced at a predetermined air flow rate.

[0085] Embodiment 15. The process according to any of the preceding embodiments, wherein aerobically fermenting a material with a thermophilic organism to provide a thermophilic fermentation culture comprises introducing at least one substance for controlling pH.

[0086] Embodiment 16. A system (200) for recycling heat in a protein culture, the system comprising: a fermenter (210) configured to aerobically ferment a material with a thermophilic organism to provide a thermophilic fermentation culture and to discharge a gas stream from the fermenter; a dryer (230) configured to dry the thermophilic fermentation culture to recover a protein culture; and a first heat exchanger (220) configured to capture heat from the discharged gas stream of the fermenter and to provide a heated air stream for the dryer using the captured heat.

[0087] Embodiment 17. The system according to embodiment 16, wherein the fermenter (210) comprises an air inlet (211) for introducing sterile air or non-sterile air.

[0088] Embodiment 18. The system according to embodiment 17, wherein sterile air or non-sterile air is introduced at a predetermined air flow rate.

[0089] Embodiment 19. The system according to any of embodiments 16 to 18, wherein the fermenter (210) comprises an air inlet (211) for introducing at least one substance for controlling pH.

[0090] Embodiment 20. The system according to any of embodiments 16 to 19, wherein the discharged gas stream has a temperature of 36°C or higher and a relative humidity of 100%.

[0091] Embodiment 21. The system according to any of embodiments 16 to 20, further comprising a second heat exchanger (240) configured to further increase the temperature of the heated air stream flowing out of the first heat exchanger (220).

[0092] Embodiment 22. A dryer (230) comprising: a first dryer (231) configured to dry a thermophilic fermentation culture by using a heated air stream; a third heat exchanger (260) configured to capture heat from a first air stream discharged from the first dryer (231) and provide a second heated air stream using the captured heat; and a second dryer (232) configured to dry the thermophilic fermentation culture by using the second air stream to recover a protein culture, the process according to Embodiments 16 to 21.

[0093] Embodiment 23. The process according to Embodiment 22, wherein the third heat exchanger is a heat pump.

[0094] Embodiment 24. The system according to Embodiments 16 to 23, further comprising an additional condenser (250) configured to heat water.

[0095] Embodiment 25. The system according to Embodiments 16 to 24, wherein the heated air stream used during drying has a temperature between 70°C and 120°C.

[0096] Embodiment 26. The system according to Embodiments 16 to 25, further comprising a clean-in-process (CIP) system configured to use heat generated during aerobic fermentation.

[0097] Although the present invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made without departing from the scope of the present invention and equivalents can be substituted for its elements. Further, many modifications can be made to adapt a particular situation or material to the teachings of the present invention without departing from its essential scope. Therefore, the present invention is not intended to be limited to the particular embodiments disclosed, but is intended to cover all embodiments falling within the scope of the appended claims.

Claims

1. A process (100) for reusing heat in a protein culture, said process comprising: - Aerobically fermenting a material with a thermophilic organism to provide a thermophilic fermentation culture (step 110); - Performing a drying process on the thermophilic fermentation culture using the heat generated during said aerobic fermentation (step 120), - said process comprising using a first heat exchanger to capture said heat from a gas stream discharged during said aerobic fermentation and heating an air stream for the drying process; Process (100).

2. The process according to claim 1, wherein said first heat exchanger is a heat pump.

3. The process according to claim 2, wherein said first heat pump uses ammonia or R1234 as a refrigerant.

4. The process according to claim 2 or 3, wherein said gas stream has a temperature of 36°C or higher and a relative humidity of 100%.

5. Said drying process comprising: - Further increasing the temperature of the air stream flowing out of said first heat exchanger using a second heat exchanger; The process according to any one of claims 1 to 4.

6. The process according to claim 5, wherein said second heat exchanger is a steam heat exchanger.

7. The process according to any one of claims 1 to 6, wherein said heated air stream used during drying has a temperature between 70°C and 120°C.

8. Said drying process comprising: - In a first step, drying said thermophilic fermentation culture using said heated air stream; - In a second step, drying said thermophilic fermentation culture using the heat generated during said first drying step. The process according to any one of claims 1 to 7.

9. Using the heat generated during said first drying step comprises capturing said heat from a first air stream discharged during said first drying step using a third heat exchanger and heating a second air stream.

10. The process according to claim 9, wherein said third heat exchanger is a heat pump.

11. - Further comprising using the waste heat generated during said aerobic fermentation to increase the temperature of a cleaning substance used in a clean in process (CIP). The process according to any one of claims 1 to 10.

12. Aerobic fermentation of materials with thermophilic organisms to provide thermophilic fermentation cultures involves - introducing sterile air or non-sterile air, The process according to any one of claims 1 to 11, comprising.

13. The process according to claim 12, wherein the sterile air or non-sterile air is introduced at a predetermined air flow rate.

14. Aerobic fermentation of materials with thermophilic organisms to provide thermophilic fermentation cultures involves - introducing at least one substance for controlling pH, The process according to any one of claims 1 to 13, comprising.

15. A system (200) for reusing heat in a protein culture, comprising - a fermenter (210), ・ Aerobically fermenting materials with thermophilic organisms to provide thermophilic fermentation cultures, ・ Discharging a gas stream from the fermenter, A fermenter (210) configured as such; - a dryer (230), ・ Drying the thermophilic fermentation culture to recover the protein culture, A dryer (230) configured as such; - a first heat exchanger (220), ・ Capturing heat from the discharged gas stream of the fermenter and using the captured heat to provide a heated air stream for the dryer, A first heat exchanger (220) configured as such A system (200) comprising.

16. The system according to claim 15, wherein the fermenter (210) includes an air inlet (211) for introducing sterile air or non-sterile air and / or for introducing at least one substance for controlling pH.

17. The system according to claim 15 or 16, wherein the discharged gas stream has a temperature of 36°C or higher and a relative humidity of 100%.

18. The system includes - a second heat exchanger (240) configured to further increase the temperature of the heated air stream flowing out of the first heat exchanger (220), The system according to any one of claims 15 to 17, further comprising.

19. The dryer (230) includes - a first dryer (231) configured to dry the thermophilic fermentation culture by using the heated air stream, - a third heat exchanger (260) configured to capture heat from the first air stream discharged from the first dryer (231) and use the captured heat to provide a heated second air stream, - A second dryer (232) configured to dry the thermophilic fermentation culture by using the second air stream to recover a protein culture The system according to any one of claims 15 to 18, comprising: **Claim 20** The process according to claim 19, wherein the third heat exchanger is a heat pump. **Claim 21** The system is - An additional condenser (250) configured to heat water The system according to any one of claims 15 to 20, further comprising: **Claim 22** The system according to any one of claims 15 to 21, wherein the dryer (230) is configured to use the heated air stream having a temperature between 70°C and 120°C. **Claim 23** - A clean-in-place (CIP) system configured to use the heat generated during the aerobic fermentation to raise the temperature of the cleaning substance The system according to any one of claims 15 to 22, further comprising:

Images