WO2025120060A1 - Cooling system and system for producing a globally usable energy carrier comprising such a cooling system - Google Patents

Abstract

The invention relates to a cooling system for dissipating process heat into the surrounding air and for extracting carbon dioxide from the surrounding air, wherein the cooling system has at least one air supply line (3) for supplying the surrounding air into a housing (1) and at least one air outlet (8) for dispensing filtered surrounding air out of the housing (1). The housing (1) is equipped with a liquor distributing unit (10) for distributing a carbon dioxide-binding liquor (9) in the housing (1), said distributing unit being integrated into a liquor circuit, and a heat exchanger (5) is positioned upstream of the liquor distributing unit (10) in the flow direction of the liquor (9) in the liquor circuit, said heat exchanger thermally coupling the liquor circuit to an exhaust heat circuit (20) of a production system.

Description

Cooling system and plant for producing a globally usable energy source with such a cooling system

The invention relates to a cooling system, a plant for producing a globally usable energy source with such a cooling system, an operating method of the plant and a cooling method.

State-of-the-art systems, such as WO 2022/096615 A1, are known to produce hydrogen by electrolysis, primarily in areas of the Earth with intensive solar radiation. The location of such systems is based on the idea of using exclusively renewable energy sources, particularly photovoltaic systems, to generate energy for hydrogen production.

The electrolytic production of hydrogen generates waste heat, which is primarily in the low-temperature range (50 °C - 150 °C). Dissipating such waste heat typically requires a natural cooling water source. Therefore, such plants are usually planned near a river or the sea to provide the necessary cooling water. This significantly limits the choice of locations for such plants. Many locations that are well-suited to generating sufficient energy using photovoltaics to operate such a plant are therefore unusable due to the lack of an appropriate cooling water source.

The object of the invention is to provide a cooling system that enables the location of plants for the electrolytic production of hydrogen to be selected independently of a natural cooling water source. Furthermore, the object of the invention is to provide a plant for producing a globally usable energy source with such a cooling system. A further object of the invention is to provide an operating method for such a plant and a cooling method. According to the invention, this object is achieved with regard to the cooling system by the subject matter of patent claim 1, with regard to the plant by the subject matter of patent claim 8, with regard to the operating method by the subject matter of patent claim 10 and with regard to the cooling method by the subject matter of patent claim 12.

Specifically, the invention is based on the idea of providing a cooling system for discharging process heat to ambient air and for extracting carbon dioxide from ambient air, wherein the cooling system has at least one air supply for supplying the ambient air into a housing and at least one air outlet for discharging purified ambient air from the housing, wherein a lye distribution unit for distributing a carbon dioxide-binding lye in the housing is arranged, which is integrated into a lye circuit, wherein a heat exchanger in the lye circuit is arranged upstream of the distribution unit in the flow direction of the lye, which heat exchanger thermally couples the lye circuit with a waste heat circuit of a production plant.

The invention is based on the discovery that low-temperature heat can be dissipated not only via a natural cooling water source, but also via the ambient air. In particular, if the carbon required for the production of alcohols and/or hydrocarbons is obtained by sorption of carbon dioxide, the carbon dioxide sorption unit can be used to simultaneously dissipate the waste heat from the production plant to the ambient air via the circulating lye, which binds carbon dioxide. This significantly expands the possibilities for locations of such production plants. In particular, a natural cooling water source can be dispensed with. This can significantly increase the total production of alcohols and/or hydrocarbons from purely renewable energies worldwide.

The cooling system can have a dual function. On the one hand, the carbon dioxide binding lye can extract carbon dioxide from the ambient air, whereby the extracted carbon dioxide can then be further processed in the production plant, in particular into alcohols and/or hydrocarbons. At the same time, the waste heat generated in the production plant can be transferred to the The carbon dioxide is returned to the carbon dioxide sorption unit, where the ambient air cools the lye, thus removing the heat from the lye. The ambient air, purified of carbon dioxide and discharged through the air outlet, also removes the heat from the lye, which the lye absorbed as waste heat during its passage through the production plant. The heat exchanger transfers the waste heat from the production plant's waste heat circuit to the lye circuit.

To maintain circulation in the lye circuit, it is preferred that a lye pump be arranged upstream of the heat exchanger in the lye circuit. Locating the lye pump in the heat exchanger's inlet is advantageous to prevent cavitation in the heat exchanger, which can occur if the heat exchanger is connected to the lye pump on the suction side. This arrangement also protects the lye pump, as it is supplied with cooled lye. This increases the service life of the lye.

The cooling system's air supply may include a fan. The fan increases the incoming air flow, thereby improving the efficiency of carbon dioxide sorption. The fan may be controlled by a controller to adjust the air flow into the housing as needed. The controller may also be configured as a closed-loop control system that uses ambient parameters, such as temperature and/or relative humidity, as input variables.

Preferably, the housing contains fillers around which air from the air supply can flow and which can be wetted with the brine by the brine distribution unit. The fillers form a large surface area that is wetted by the brine, thus creating a large exchange area between the brine and the ambient air. This increases the efficiency of carbon dioxide sorption. Specifically, the carbon dioxide binds to the brine and can thus be removed with the brine.

The lye distribution unit is preferably arranged above and/or below the packing elements. The packing elements can rest on a grate. The lye distribution unit can, in particular, comprise a spray device for finely spraying the lye onto the packing elements. The spray device is preferably arranged above the packing elements, but can also be arranged below the packing elements. In a preferred embodiment of the cooling system according to the invention, the air supply and the lye circuit are arranged such that the ambient air is supplied in countercurrent and/or cocurrent flow relative to the flow direction of the lye. The air supply can therefore be oriented such that the air flow and the lye flow are in the same direction (cocurrent flow). Alternatively, the air supply and the lye circuit can also be arranged such that the air flow and the lye flow are in opposite directions (countercurrent flow).

It is advantageous if caustic soda, potassium hydroxide, or a mixture comprising caustic soda and potassium hydroxide circulates in the caustic cycle. Such caustic solutions or mixtures have been shown to be particularly well-suited for extracting carbon dioxide from the ambient air and for releasing low-temperature heat from a production facility to the ambient air.

The invention also relates to a plant, in particular a production plant, for producing a globally usable energy source. The plant preferably has a photovoltaic unit for converting solar energy into electricity, which has an output, in particular a peak output, of at least 1.0 gigawatts, in particular at least 1.3 gigawatts, in particular at least 1.5 gigawatts. Furthermore, the plant comprises a water supply unit, in particular a seawater desalination unit for producing desalinated water, which has an absorption capacity of at least 900,000 tons of additional water per year. In addition, an electrolysis unit for producing hydrogen is provided, which is connected by at least one pipeline to the water supply unit, in particular the seawater desalination unit, for supplying water, in particular desalinated water.

The plant comprises a cooling system as described above and a synthesis unit for producing hydrocarbons, in particular synthetic methanol, which is connected by at least one pipeline to the electrolysis unit for supplying hydrogen and by at least one pipeline to the cooling system for supplying carbon dioxide. In the system according to the invention, the water supply unit, in particular the seawater desalination unit, the electrolysis unit, the cooling system, and/or the synthesis unit for absorbing process heat, are coupled to a waste heat circuit, which is thermally coupled to a liquor circuit of the cooling system via a heat exchanger. To ensure the location independence of the system, the water supply unit can, for example, comprise a device for extracting water from ambient air. Such a device for extracting water from ambient air can at least reduce the need for other water sources. The system can thus also be used at locations that otherwise provide an inadequate natural water supply.

It is advantageous in any case if the water supply unit, in particular the seawater desalination unit, the electrolysis unit, the cooling system, and the synthesis unit are each connected to the photovoltaic unit for power supply and arranged in a contiguous system area with the photovoltaic unit. The photovoltaic unit is preferably adapted to absorb at least 1500 kWh/ ^m² per year, in particular at least 2000 kWh/ ^m² per year, in particular at least 2300 kWh/ ^m² per year, in particular at least 2500 kWh/ ^m² per year, in particular at least 2700 kWh/m² ^per year, of solar energy. The synthesis unit can have a delivery capacity of at least 300,000 tonnes, in particular at least 450,000 tonnes, of renewably produced hydrocarbons per year.

A further aspect of the invention relates to a method for operating a previously described plant, in which a quantity of water is taken up by the electrolysis unit for oxygen production through at least one water supply line, and the taken-up quantity of water is split into a partial quantity of oxygen and a partial quantity of hydrogen by electrolysis; the partial quantity of hydrogen is at least partially passed to a carbonation unit, in particular a Bosch reaction unit, by at least one hydrogen transport device; Ambient air of an external atmosphere surrounding the plant is purified by a previously described cooling system, wherein the ambient air is supplied to a housing through at least one air supply and then a quantity of carbon dioxide is extracted from the supplied ambient air; and the quantity of carbon dioxide is passed to the carbonization unit through at least one carbon dioxide transport device,

- whereby the oxygen partial quantity and the purified ambient air are released into the outside atmosphere and the hydrogen partial quantity and the carbon dioxide quantity are converted in the carbonation unit into water, carbon, heat and other chemical products, for example glycol.

The waste heat from the electrolysis unit and/or the carbonization unit is transferred via a waste heat circuit and a heat exchanger to a liquor circuit of the cooling system and released from the cooling system to the outside atmosphere.

Preferably, sodium hydroxide, potassium hydroxide, or a mixture comprising sodium hydroxide and potassium hydroxide circulates in the lye circuit and is passed through the electrolysis unit as an electrolyte. The use of sodium hydroxide is particularly advantageous because, on the one hand, sodium hydroxide serves as an electrolyte suitable for extracting carbon dioxide from the ambient air, and, on the other hand, it represents an effective cooling medium. This dual function of sodium hydroxide is utilized particularly efficiently within the scope of the present invention.

A further aspect of the invention relates to a cooling process with release of process heat and absorption of carbon dioxide, which comprises the following steps:

Providing a previously described cooling system and

Circulating a lye through the lye circuit of the cooling system by means of a lye pump, The lye absorbs heat from a waste heat cycle and releases it to the ambient air when absorbing carbon dioxide. The waste heat cycle is preferably integrated into a production plant for the production of hydrocarbons, in particular methanol.

For all aspects of the invention described here, it is advantageous if the alkali has a concentration such that the alkali is in equilibrium with the environment. In particular, the method can provide for the concentration of the sodium hydroxide solution to be selected to be at least high enough that in the cooling system, in particular in a carbon dioxide sorption unit and/or a housing of the cooling system, the partial pressure of water in the aqueous solution of the sodium hydroxide solution corresponds at most to the partial pressure of water in the ambient air. In this way, it is achieved that, despite the elevated temperature of the sodium hydroxide solution, no water is lost to the ambient air through evaporation. Rather, the heat is released from the aqueous sodium hydroxide solution by convection.

The invention will be explained in more detail below using an exemplary embodiment with reference to the attached schematic drawings.

Fig. 1 is a cross-sectional view of a countercurrent cooling system according to the invention in accordance with a preferred embodiment;

Fig. 2 is a cross-sectional view of a direct current cooling system according to the invention according to a preferred embodiment; and

Fig. 3 is a process diagram of a plant according to the invention for producing a globally usable energy source with removal of the process heat via the cooling system described above.

Figures 1 and 2 each show a cooling system that, on the one hand, enables the release of process heat to the ambient air and, at the same time, extracts carbon dioxide from the ambient air. Particularly in the extraction of carbon dioxide from the ambient air, large quantities of ambient air are blown through a bed wetted with a concentrated sodium hydroxide solution. This requires intensive mass transfer between the The caustic soda solution and the air are required. This intensive mass transfer is used to simultaneously release excess low-temperature waste heat into the ambient air. However, evaporative cooling is not the primary focus here, as the highly concentrated caustic soda solution is preferably adjusted to release hardly any water into the ambient air. Rather, heat transfer from the solution to the ambient air occurs primarily through convection.

The cooling systems shown in Figures 1 and 2 each comprise a housing 1 in which several fillers 11 are arranged on a perforated grid or grate 6. The grate 6 retains the fillers 11. Below the grate 6, an air inlet 3 opens into the housing 1. The air inlet 3 comprises a fan 2, which draws in ambient air and blows it into the housing 1 via the air inlet 3.

Above the filler elements 11, the housing 1 has an air outlet funnel 7, which opens into an air outlet 8. The air outlet 8 is spatially separated from the air supply 3. The purified ambient air is released into the environment via the air outlet 8.

A lye distribution unit 10 is arranged above the packing elements 11. The lye distribution unit 10 can have several spray devices that spray the lye 9 over the packing elements 11. This wets the packing elements 11 with the lye 9. The lye 9, which is shown by framed arrows in Figures 1 and 2, passes through the packing elements 11 or the bed of packing elements 11. In the cooling system according to Figure 1, the ambient air flows through the bed of packing elements 11 in the opposite direction to the flow direction of the lye 9. The cooling system according to Figure 1 is therefore a countercurrent cooling system. In the cooling system according to Figure 2, however, the ambient air flows through the bed of packing elements 11 in the same direction as the flow direction of the lye 9, i.e., the cooling system is used in cocurrent operation. In both cases, the filling bodies 11 are surrounded by the ambient air.

The flow direction of the ambient air is shown in Figures 1 and 2 by solid arrows. On the one hand, the lye 9 exchanges carbon dioxide with the ambient air, whereby carbon dioxide is bound in the lye. On the other hand, the lye 9 simultaneously releases heat to the ambient air. Heated ambient air leaves the housing 1 via the air outlet funnel 7 and the air outlet 8.

The lye 9, which has since been enriched with carbon dioxide, falls through the grate 6 into a basin at the bottom of the housing 1. There, the collected and carbon dioxide-enriched lye 9 is pumped out via a lye pump 4 and passed through a heat exchanger 5. The heat exchanger 5 is coupled to a waste heat circuit of a production plant, so that waste heat generated in the production plant, in particular low-temperature waste heat with a temperature level between 50 °C and 150 °C, is transferred to the lye 9. The lye 9 thus absorbs waste heat from the production plant in the heat exchanger 5. The now heated lye 9 reaches the lye distribution unit 10 and is again distributed via the packing elements 11.

The lye circuit thus comprises the lye pump 4, the heat exchanger 5, the lye distribution unit 10, and the cooling system housing 1. The lye 9 circulates continuously within the lye circuit.

The cooling systems shown in Figures 1 and 2 are particularly simple and cost-effective to manufacture. In particular, to save costs, the essential components, such as the housing 1, the grate 6, the air outlet funnel 7, the lye distribution unit 10, and/or the filler elements 11, can each be made of plastic.

The cooling system is preferably controlled such that the mass flow of the ambient air through the bed of packing elements 11 is at least one order of magnitude greater than the mass flow of the lye 9. In other words, preferably at least ten times the mass flow of the ambient air is passed through the bed of packing elements 11 compared to the mass flow of the lye 9. This ensures that the air temperature at the air outlet 8 is increased by a maximum of approximately 3° Kelvin. At the same time, the lye leaves the bed of packing elements 11 at a temperature level that is close to the temperature level of the supplied ambient air.

It is surprising that increasing the temperature of the liquor 9 through the heat exchanger 5 leads to an improvement in the distribution of the Lye 9, particularly its viscosity, and thus the efficiency of carbon dioxide absorption. Lye 9, particularly sodium hydroxide, also serves as both an electrolyte and a cooling medium, so that in a production plant with an electrolysis unit, an additional cooling circuit in the electrolysis can be avoided.

Fig. 2 shows a process diagram of a plant for the production of methanol using renewable energy. The feedstocks used are water, sunlight, and ambient air. The water can be provided, for example, as seawater if the plant is installed near a sea. Alternatively, the water can also be obtained by extracting water from ambient air.

When seawater, i.e., saline water, is provided, it is first desalinated, producing pure water. This pure water is fed to an electrolysis unit. The energy for the electrolysis is provided by a photovoltaic unit 24, which uses sunlight as the starting material. The electrolysis leads to the production of oxygen, which is released into the ambient air. Furthermore, hydrogen is produced by the electrolysis, which, along with energy and carbon dioxide, is fed to a synthesis unit. In the embodiment shown in Fig. 2, methanol synthesis takes place in the synthesis unit, producing methanol.

The carbon dioxide for methanol synthesis is provided by sorption from the ambient air. A corresponding carbon dioxide sorption unit absorbs ambient air and extracts the carbon dioxide from it. This can be achieved, for example, by a cooling system as shown in Fig. 1.

In the methanol synthesis unit, in addition to methanol, water is also produced, which is advantageously fed back to the electrolysis unit so that the water produced in the methanol synthesis unit can be recycled to produce hydrogen by electrolysis.

The cooling system shown in Fig. 1 is not shown separately in Fig. 2. Rather, the cooling system is an integral part of the carbon dioxide sorption unit 23, which is referred to as "CCh sorption" in the process diagram. The process diagram in Fig. 2 shows that heat is generated during electrolysis. This heat is removed from the electrolysis unit 21 via a low-temperature waste heat circuit 20. The low-temperature waste heat circuit 20 is also connected to the methanol synthesis unit 22, so that process heat generated during methanol synthesis is also transferred to the low-temperature waste heat circuit 20. All of the waste heat from the electrolysis and methanol synthesis is then conducted to the carbon dioxide sorption unit 23 via the low-temperature waste heat circuit 20 or transferred to the lye circuit via the heat exchanger 5. The lye 9 is heated in the process, which leads to more efficient use of the lye 9. At the same time, the heat from the lye 9 is removed via the carbon dioxide sorption unit 23, so that the overall process heat can be dissipated to the environment via the lye circuit. It is important that the heat is not dissipated via a natural cooling water source as usual, but rather is dissipated into the ambient air, thus creating location independence with regard to the cooling of the system.

1 housing

2 fans

3 Air supply

4 Drain pump

5 heat exchangers

6 Rust

7 air outlet funnels

8 Air outlet

9 Lye

10 Lye distribution unit

11 packing

20 Low-temperature waste heat cycle

21 Electrolysis unit

22 Methanol synthesis unit

23 Carbon dioxide sorption unit

24 photovoltaic units

25 water supply unit

26 Seawater Desalination Unit

Claims

Patent claims 1. Cooling system for discharging process heat to ambient air and for extracting carbon dioxide from ambient air, the cooling system comprising at least one air inlet (3) for supplying the ambient air into a housing (1) and at least one air outlet (8) for discharging purified ambient air from the housing (1), a lye distribution unit (10) for distributing a carbon dioxide-binding lye (9) in the housing (1) being arranged in the housing (1), which lye distribution unit is integrated into a lye circuit, a heat exchanger (5) being arranged upstream of the lye distribution unit (10) in the flow direction of the lye (9) in the lye circuit, which heat exchanger thermally couples the lye circuit with a waste heat circuit (20) of a production plant. 2. Cooling system according to claim 1, characterized in that a lye pump (4) is arranged upstream of the heat exchanger (5) in the lye circuit. 3. Cooling system according to claim 1 or 2, characterized in that the air supply (3) comprises a fan (2). 4. Cooling system according to one of the preceding claims, characterized in that filling bodies (11) are arranged in the housing (1), around which air from the air supply (3) can flow and which can be wetted with the lye (9) by the lye distribution unit (10). 5. Cooling system according to claim 4, characterized in that the lye distribution unit (10) is arranged above and/or below the filling bodies (11) which rest on a grate (6). 6. Cooling system according to one of the preceding claims, characterized in that the air supply (3) and the lye circuit are arranged such that the supply of ambient air takes place in countercurrent and/or cocurrent with respect to the flow direction of the lye (9). 7. Cooling system according to one of the preceding claims, characterized in that caustic soda, potassium hydroxide or a mixture comprising caustic soda and potassium hydroxide circulates in the lye circuit. 8. A plant for producing a globally usable energy source, comprising a photovoltaic unit (24) for converting solar energy into electricity, which has a power output, in particular a peak power of at least 1.0 gigawatts, in particular at least 1.3 gigawatts, in particular at least 1.5 gigawatts, a water supply unit (25), in particular a seawater desalination unit (26) for producing desalinated water, which has an absorption capacity of at least 900,000 tons of seawater per year, an electrolysis unit (21) for producing hydrogen, which is connected by at least one pipeline to the water supply unit (25), in particular the seawater desalination unit (26), for supplying water, in particular desalinated water, a cooling system according to one of the preceding claims, a synthesis unit for producing hydrocarbons, in particular synthetic methanol, which is connected by at least one pipeline to the electrolysis unit (21) for supplying hydrogen and by at least one pipeline to the cooling system for supplying carbon dioxide, the water supply unit (25), in particular seawater desalination unit (26), the electrolysis unit (21), the cooling system and/or the synthesis unit for absorbing process heat is coupled to a waste heat circuit (20) which is thermally coupled to the lye circuit of the cooling system via the heat exchanger (5). 9. Plant according to claim 8, characterized in that the water supply unit (25), in particular seawater desalination unit (26), the electrolysis unit (21), the cooling system and the synthesis unit are each connected to the photovoltaic unit (24) for power supply and are arranged in a connected plant area with the photovoltaic unit (24), the photovoltaic unit (24) is adapted to absorb at least 1500 kWh/m ² a, in particular at least 2000 kWh/m ² a, in particular at least 2300 kWh/m ² a, in particular at least 2500 kWh/m ² a, in particular at least 2700 kWh/m ² a, of solar energy and the synthesis unit has a delivery capacity of at least 300,000 tonnes, in particular at least 450,000 tonnes, of renewably produced hydrocarbons per year. 10. A method for operating a plant according to claim 8 or 9, wherein a quantity of water (M _H 2o) is taken up by the electrolysis unit (21) for oxygen production through at least one water supply line and the taken-up quantity of water (M _H 2o) is split by electrolysis into a partial quantity of oxygen ( _MO2 ) and a partial quantity of hydrogen; the partial quantity of hydrogen is passed at least partially to a carbonation unit, in particular a Bosch reaction unit, by at least one hydrogen transport device; Ambient air of an external atmosphere surrounding the system is cleaned by a cooling system according to one of claims 1 to 7, wherein the ambient air is supplied to a housing through at least one air supply (3) (1) and then an amount of carbon dioxide is extracted from the supplied ambient air; and the amount of carbon dioxide is passed through at least one carbon dioxide transport device to the carbonation unit, wherein the partial amount of oxygen ( _MO2 ) and the purified ambient air are released into the outside atmosphere and the partial amount of hydrogen and the amount of carbon dioxide are converted in the carbonation unit to water, carbon, heat and other chemical products, for example glycol, and wherein waste heat from the electrolysis unit (21) and/or the carbonation unit is transferred via a waste heat circuit (20) and a heat exchanger (5) to a liquor circuit of the cooling system and is released from the cooling system to the outside atmosphere. 11. The method according to claim 10, characterized in that sodium hydroxide solution, potassium hydroxide or a mixture comprising sodium hydroxide solution and potassium hydroxide circulates in the lye circuit and is passed through the electrolysis unit (21) as electrolyte. 12. Cooling process with release of process heat and absorption of carbon dioxide, comprising the following steps: Providing a cooling system according to any one of claims 1 to 7 and Circulating a lye (9), in particular caustic soda, through the lye circuit of the cooling system by means of a lye pump (4), wherein the lye (9) absorbs heat from a waste heat circuit (20) and releases it to the ambient air when absorbing carbon dioxide. 13. Cooling method according to claim 12, characterized in that the concentration of the alkali (9) is selected to be at least high enough that in the cooling system, in particular in a carbon dioxide sorption unit (23) and/or a housing (1) of the cooling system, the partial pressure of water in the aqueous solution of the alkali corresponds at most to the partial pressure of water in the ambient air.