System of thermally coupled process devices

The system of heat-coupled process devices with thermal storage and a heat pump addresses the challenge of intermittent renewable energy by efficiently coupling processes with different operation times, optimizing energy use and reducing costs through flexible heat management.

WO2025172015A1PCT designated stage Publication Date: 2025-08-21SIEMENS ENERGY GLOBAL GMBH & CO KG
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Patent Information

Application Number
PCT/EP2025/051639
Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
Priority Date
2024-02-14
Filing Date
2025-01-23
Publication Date
2025-08-21

AI Technical Summary

Technical Problem

Chemical and food technology processes face challenges in operating intermittently due to the fluctuating availability of renewable energy, leading to mismatched waste heat supply and demand, high capital expenditures, and inefficiencies in energy utilization, especially when processes require continuous operation.

Method used

A system of heat-coupled process devices utilizing a heat pump to raise waste heat from one process to a suitable level for another, with thermal storage units to store and adjust heat flows, allowing flexible operation and efficient utilization of renewable energy.

Benefits of technology

Enables efficient coupling of processes with different operation times, optimizing energy use and reducing costs by storing heat and adjusting temperature levels with an energy-efficient heat pump, facilitating the use of volatile energy sources.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention relates to a system (1) of thermally coupled processes, wherein the system (1) has: at least one heat-emitting process device (P1) which is designed to carry out a technical process and thereby emit waste heat at a temperature T1; at least one heat-absorbing process device (P2) which is designed to carry out a technical process and thereby absorb heat at a temperature T2 which is higher than T1; a heat pump (10) which is designed to increase the waste heat of the heat-emitting process device (P1) from T1 to T2; and a T1 store (20), which is a thermal store, arranged between the heat-emitting process device (P1) and the heat pump (10) and designed to store the waste heat of the heat-emitting process device (P1), preferably at the temperature T1, and / or a T2 store (30), which is a thermal store, arranged between the heat pump (10) and the heat-absorbing process device (P2) and designed to store the heat to be absorbed by the heat-absorbing process device (P2), preferably at the temperature T2.
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Description

[0001] Description

[0002] System of heat-coupled process equipment

[0003] The application relates to a system of heat-coupled process devices and a method for operating such a system.

[0004] In chemical, energy, and process engineering, thermally coupling processes is common practice. This involves a process releasing waste heat, which is then fed into another process for use instead of being discarded, thus optimizing overall energy use. Numerous examples of such process coupling are known, such as electrolysis, thermocatalytic processes, drying, pyrolysis, and the like. These are generally processes that run continuously (24 / 7). If waste heat is available at a higher temperature level, it can be continuously used to supply other processes at a lower temperature level (temperature cascade).

[0005] In the context of the decarbonization of chemical and food technology processes, especially petrochemical processes, there is a desire to operate processes with renewable energy. However, this energy is not necessarily available continuously (24 / 7), which may require the processes to be operated intermittently depending on the availability of volatile energy. Some processes are fundamentally unsuitable for such intermittent operation, for example, many thermocatalytic processes in refineries, for example, those used to produce ammonia, methane, methanol, gasoline, or diesel. For some processes, capital expenditures are very high, so limited machine utilization ("load factor") significantly increases the product's cost. This can lead to situations where it is most economical to operate only certain processes intermittently and supply others with conventional energy and run them continuously.Examples of intermittent processes generally include highly energy-intensive processes that operate only when renewable energy is readily available and generate waste heat (electrolysis, compression, etc.). Continuous processes include, for example, chemical-technical processes for extracting CO2 from the ambient air (direct air CO2 capture), water treatment by distillation / evaporation, thermocatalytic processes, drying, sterilization, food preparation (cooking, baking), melting plastics for extrusion, and others.

[0006] In the case of continuous processes, the mandatory continuous waste heat transfer is not possible, even if renewable energy is available. This results in the problem of different operating times for the intended use of waste heat, for example, from an intermittently operated process for heat generation with a continuously operated process (fluctuating waste heat supply vs. continuous operation of the process). Furthermore, the temperature of the waste heat source may be too low.

[0007] To solve these problems, all processes could be operated with continuously available energy from the power grid, which, however, would result in correspondingly high CCy emissions. Alternatively, the processes could be operated only when renewable energy is available. However, this is often not possible, as many processes must be operated continuously for technical reasons or are not economical, especially in the case of CAPEX-intensive processes with low load factors. The use of batteries to provide electrical energy when renewables are unavailable is generally not economical, as storing electrical energy is very resource- and cost-intensive.Alternatively, if renewable energy is not available, electricity could be drawn from the grid. However, due to the electricity mix in the grids, this generally does not meet the criterion of a purely renewable energy supply and prevents the use of temporarily cheap renewable energy.

[0008] An object of the invention is to provide an improved system of heat-coupled process devices and an improved method for operating such a system.

[0009] This object is achieved by a system having the features of claim 1 and a method having the features of the subordinate method claim. Advantageous further developments follow from the subclaims, the following description of the invention, and the description of preferred embodiments.

[0010] The invention relates to a system of heat-coupled processes. These are technical, industrial processes, in particular from the chemical, energy, and / or process engineering sectors, including, for example, electrolysis and / or DAC (Direct Air Capture).

[0011] The system comprises at least one heat-emitting process device configured to carry out a technical process and thereby release waste heat at a temperature T1, and at least one heat-absorbing process device configured to carry out a technical process and thereby absorb and utilize heat at a temperature T2 higher than T1. The system has a heat pump configured to raise the waste heat of the heat-emitting process device from T1 to T2.

[0012] The heat pump thermally couples the two processes, i.e., it provides a heat flow from the heat-emitting process to the heat-absorbing process and modifies this flow to raise the waste heat from one process to a suitable level for the heat-absorbing process. Heat transfer occurs via a suitable heat medium, which can be liquid or gaseous.

[0013] The system further comprises a T1 storage device, which is a thermal storage device, arranged between the heat-emitting process device and the heat pump and is designed to store the waste heat of the heat-emitting process device, preferably at the temperature T1 or in a temperature range around T1, and / or a T2 storage device, which is a thermal storage device, arranged between the heat pump and the heat-absorbing process device and is designed to store the heat to be absorbed by the heat-absorbing process device, preferably at the temperature T2 or in a temperature range around T2.

[0014] It should be noted that the preposition "between" and the like in the present context refers to the heat flow and does not necessarily define a spatial relationship. Furthermore, for the sake of linguistic simplicity, reference is usually made to a heat-emitting process device and a heat-absorbing process device. However, the invention analogously encompasses the thermal coupling of several process devices or processes on the heat-emitting side and / or the heat-absorbing side.

[0015] The system takes advantage of the fact that, unlike electricity, heat and / or process gases can be stored much more cost-effectively and with less resource consumption. This allows the processes of the process facilities, especially when they run at different times, to be advantageously coupled without burdening the overall process with excessive costs or resource consumption. The system thus allows the coupling of processes operating at different times if the temperature level of the heat-emitting process is below the temperature level of the heat-absorbing process.

[0016] The system also enables heat coupling between continuously and intermittently operated processes. This allows for flexible adaptation of the system to the use of temporarily available or volatile energy, such as renewable energy. The system allows for adjustment of the temperature levels between the heat-emitting process and the heat-absorbing process using an energy-efficient heat pump, whose operating time can in turn be adjusted to the availability of electrical energy. The system thus enables ideal waste heat utilization, for example, in the production of synthetic fuels or energy sources.

[0017] The heat pump is preferably configured to deliver cold at a temperature T3 and supply it to the heat-dissipating process device. This usually occurs via an evaporator of the heat pump. A T3 storage unit, which is a thermal storage unit, can be arranged between the heat pump and the heat-dissipating process device and configured to store the cold delivered by the heat pump, preferably at temperature T3. The low temperature T3 delivered by the heat pump can be supplied to the heat-dissipating process as actively generated cold. This utilization of the heat pump's cooling capacity is particularly advantageous at high ambient temperatures, eliminates the need for a cooling device (air cooling, water cooling), and often also improves the efficiency of the heat-dissipating process.

[0018] The effects can be enhanced with a cooling device arranged between the heat pump and the heat-emitting process device or the T3 storage tank, and configured to cool the cold released by the heat pump at temperature T3 to a lower temperature T3 '. The cooling device is implemented, for example, by air cooling, cooling with ambient water, or another heat pump used for cooling. This enables even more effective cooling of the heat-emitting process.

[0019] It is possible to utilize the waste heat from the heat-absorbing process. In this case, the heat-absorbing process absorbs heat at a temperature of T2 and releases heat at a colder temperature level T4. Preferably, the heat-absorbing process device is thus configured to release waste heat at a temperature T4 and supply it to the heat pump. A T4 storage device, which is a thermal storage device, can be arranged between the heat-absorbing process device and the heat pump and configured to store the waste heat released by the heat-absorbing process, preferably at temperature T4.

[0020] If the temperature T4 is below the temperature level delivered by the heat pump, then a circuit in which the colder temperature T4 (if necessary via the T4 storage tank) is used to cool the heat-generating process is advantageous. The temperature level T3 delivered by the heat pump or its evaporator is preferably used to generate the heat supply at T2. Possible examples of heat-absorbing processes with a very low output temperature T4 include drying or DAC technologies with amine-based capture molecules. The system is thus preferably designed to supply the waste heat, preferably at temperature T4, to the heat-absorbing process device or the T4 storage tank, to the heat-emitting process device or the T3 storage tank for cooling, bypassing the heat pump. The cold at T3 from the heat pump can preferably be supplied to the Ti storage tank.

[0021] The circuit is preferably switchable between different configurations, including those mentioned above, by means of a switching valve.

[0022] The technical processes of the processing facilities often provide starting materials that are then converted into the actual target substances in a large-scale synthesis process (e.g., methanol synthesis, reverse water gas shift reaction followed by a Fischer-Tropsch process). In this case, it may be useful to provide one or more product buffer storage units, each configured to store a starting product from the corresponding process facility.

[0023] Pressure accumulators made of metal or plastic, in particular fiber-reinforced plastic, can be used as product buffer storage, which are preferably dimensioned so that process interruptions of hours to days can occur before the starting product runs out.

[0024] Preferably, the heat-emitting process device and / or the heat-absorbing process device and / or the heat pump draw electrical energy for regular operation. This system provides an economically advantageous solution, particularly for renewable or otherwise volatile electrical energy. For example, when electrical energy is available, the heat pump can be operated to raise the waste heat from the T1 storage tank to a higher temperature level and feed it into the T2 storage tank. In this way, the heat-coupled processes and the heat pump can be operated independently to a certain extent, thus responding to the availability of volatile energy sources.

[0025] The heat-emitting process device and / or the heat-absorbing process device and / or the heat pump preferably operate intermittently, i.e., not continuously. In particular, the processes of the process devices and the heat pump do not necessarily have to run simultaneously due to the thermal storage.

[0026] The system preferably comprises a control device for controlling and / or regulating the processes and heat flows. In particular, the control device is configured to obtain information about the fill levels of the thermal storage units and to control the heat pump in such a way that sufficient process heat is always available for the heat-absorbing process device.

[0027] The processes of the process equipment and their coupling via the heat pump and the thermal storage are controlled and / or regulated by the control device. The control device particularly controls / regulates the times at which the processes are operated. In addition to system parameters, the control device uses information on available renewable energy, prices, availability forecasts, and the fill levels of the thermal storage. One goal of the control device is preferably to control the heat pump in such a way that sufficient process heat is always available for the heat-absorbing process, if possible at the lowest cost or with maximum utilization of renewable energy. In addition, the control device can use the key system parameters for monitoring purposes by checking the plausibility of the interaction of the system parameters.

[0028] The control device is connected in terms of signal technology to the components of the system to be controlled or regulated and / or read out, with any integrated sensors, for example for temperatures, fill levels and / or throughput quantities, and thus in particular to the process devices, the heat pump and the thermal storage devices.

[0029] Communication between the control device and the components to be controlled or regulated and / or read can be wired or wireless, digital or analog. The control device can receive and / or transmit signals (control signals, data, etc.) accordingly, whereby both one-way and two-way signal transport fall under the term "communication" in this context. The control device does not necessarily have to be implemented by a central computing device or electronic control system; rather, decentralized and / or multi-level systems, control networks, cloud systems, and the like are included. The control device can also be an integral part of a higher-level system control system or communicate with such a system.

[0030] Preferably, the heat-releasing process device is an electrolyzer for generating H2 or directly reducing CO2. Alternatively or additionally, the heat-receiving process device can be configured to perform a DAC process to provide CO2.

[0031] The above-mentioned object is further achieved by a method for operating a system of heat-coupled processes, the method comprising: carrying out a technical process, which in the process releases waste heat at a temperature T1, by means of a heat-releasing process device; carrying out a further technical process, which in the process absorbs heat at a temperature T2 that is higher than T1, by means of a heat-absorbing process device; raising the waste heat of the heat-releasing process from T1 to T2 by means of a heat pump; storing the waste heat of the heat-releasing process in a T1 storage device, which is a thermal storage device and is arranged between the heat-releasing process device and the heat pump, and / or storing the heat to be absorbed by the heat-absorbing process in a T1 storage device, which is a thermal storage device and is arranged between the heat pump and the heat-absorbing process device.

[0032] The features, technical effects, advantages and embodiments described with regard to the system apply analogously to the method.

[0033] For the reasons stated above, the heat-emitting process and the heat-absorbing process are preferably not carried out simultaneously, at least temporarily.

[0034] For the reasons stated above, the heat pump preferably releases cold at a temperature T3 and supplies it to the heat-emitting process device, wherein preferably a T3 storage device, which is a thermal storage device, is arranged between the heat pump and the heat-emitting process device and stores the cold released by the heat pump, preferably at the temperature T3.

[0035] For the reasons stated above, the heat-absorbing process device preferably releases waste heat at a temperature T4 and feeds it to the heat pump, wherein a Ti storage device, which is a thermal storage device, is preferably arranged between the heat-absorbing process device and the heat pump and stores the waste heat released by the heat-absorbing process, preferably at temperature T4. Further advantages and features of the present invention will become apparent from the following description of preferred exemplary embodiments. The features described therein can be implemented alone or in combination with one or more of the features set out above, provided the features do not contradict one another. The following description of preferred exemplary embodiments is made with reference to the accompanying drawings.

[0036] Preferred further embodiments of the invention are explained in more detail in the following description of the figures. In the figures:

[0037] Figure 1 shows a schematic diagram of a system with heat-coupled process equipment and thermal storage;

[0038] Figure 2 schematically shows a system with heat-coupled process devices and thermal storage devices according to a further embodiment;

[0039] Figure 3 schematically shows a system with heat-coupled process devices and thermal storage devices according to a further embodiment;

[0040] Figure 4 schematically shows a system with heat-coupled process devices, thermal storage and an additional cooling device according to a further embodiment;

[0041] Figure 5 schematically shows a system with heat-coupled process devices, thermal storage and additional use of cold discharge temperatures of the heat-absorbing process according to a further embodiment;

[0042] Figure 6 shows schematically a system with heat-coupled process equipment, thermal storage and variable use of low temperatures with switching option according to another

[0043] embodiment; and

[0044] Figure 7 schematically shows a system with heat-coupled process devices, thermal storage and product buffer storage according to a further embodiment.

[0045] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the different figures are provided with identical reference numerals, and a repeated description of these elements is partially omitted to avoid redundancy.

[0046] In the figures, electrical power supplied by corresponding devices E is represented by single-line arrows. Double-line arrows indicate heat flow.

[0047] Figure 1 schematically shows a system 1 with two heat-coupled process devices PI and P2 and several thermal storage devices 20, 30, 40, 50.

[0048] The process facilities P1 and P2 are each configured to perform a technical process, for example, electrolysis in the case of the process facility P1 and DAC (Direct Air Capture) in the case of the process facility P2. The process facility P1 performs a heat-releasing process, while the process facility P2 performs a heat-absorbing process. The terms "process facility" and "process" are sometimes used synonymously herein.

[0049] Figure 1 shows a heat flow in system 1 using double arrows. Heat transfer occurs via a suitable heat medium, which can be liquid or gaseous. The heat medium in system 1 is preferably water, possibly under pressure. However, other heat transfer media such as alcohols, thermal oils, or even gases are also possible.

[0050] System 1 comprises a heat pump 10, via which the two process devices P1, P2 are thermally coupled. Heat pump 10 is configured to transform supplied heat at a temperature T1 (waste heat from the heat-emitting process device) into heat at a higher temperature level T2 (supply heat from the heat-absorbing process device P2) using technical work, for example, by means of an electrically driven compressor, and thereby release cold at a temperature level T3.

[0051] For this purpose, the heat pump 10, comprising an evaporator 11 and a condenser 12, operates with a heat transfer medium selected to ensure the transformation of the waste heat temperature level to the desired high temperature level is as economical as possible. In addition to the appropriate selection of the working medium, the pressure levels of the heat pump process are also optimally adjusted where possible.

[0052] During operation of the heat-emitting process PI, its waste heat at temperature TI is introduced into a thermal storage unit 20, also referred to herein as the "Tl storage unit." At a suitable time, the heat pump 10 uses the Tl storage unit 20 as a heat source to generate heat at a higher temperature level T2 > TI and store it in a second thermal storage unit 30, also referred to herein as the "Ti storage unit." The heat-absorbing process P2 can then be fed from the T2 storage unit 30. The heat T4 released therefrom can be supplied to the condenser 12 of the heat pump 10.

[0053] Particularly when renewable electrical energy is available, the heat pump 10 can be operated to raise the waste heat from the T1 storage tank 20 to the higher temperature level T2 and feed it into the T2 storage tank. In this way, the heat-coupled processes P1, P2, and the heat pump 10 can be operated independently to a certain extent and thus respond to the availability of volatile energy.

[0054] The low temperature T3 released by the evaporator 11 of the heat pump 10 can be fed to the heat-dissipating process PI as actively generated cold. Such utilization of the cooling capacity of the heat pump 10 is particularly advantageous at high ambient temperatures, eliminates the need for a cooling device (air cooling, water cooling), and often also improves the efficiency of the heat-dissipating process PI.

[0055] Preferably, the system comprises additional thermal storage units 40, 50 for the intermediate storage of the cold temperature level T3 of the heat pump 10 and the waste heat T4 of the heat-absorbing process P2. The thermal storage unit 40 for supplying the heat-emitting process P1 with cold is also referred to herein as the "T3 storage unit." The thermal storage unit 50 for the waste heat of the heat-absorbing process P2 is also referred to herein as the "T4 storage unit."

[0056] System 1 allows the use of the waste heat from process PI, which is too cold for the heat-absorbing process P2. Furthermore, the two processes PI, P2, and the heat pump 10 can be operated independently of each other.

[0057] The processes P1, P2 and their coupling via the heat pump 10 and the thermal storage units 20, 30, 40, 50 are controlled and / or regulated by a control device 100. The control device 100 controls / regulates, in particular, the times at which the processes P1, P2 are operated. In addition to system parameters, the control device 100 uses, for example, information about the available renewable energy, prices and availability forecasts, as well as about the filling levels of the thermal storage units 20, 30, 40, 50. One aim of the control device 100 is to control the heat pump 10 such that sufficient process heat is always available for the heat-absorbing process P2, if possible at the lowest cost or with maximum utilization of the renewable energies. In addition, the control device 100 can use the essential system parameters for monitoring by checking the interaction of the system parameters for plausibility.

[0058] The control device 100 is signal-connected to the components of the system 1 to be controlled or regulated and / or read out, thus in particular to the processes P1, P2, the heat pump 10 and the thermal storage units 20, 30, 40, 50.

[0059] Communication between the control device 100 and the components to be controlled or regulated and / or read can be wired or wireless, digital or analog. The control device 100 can receive and / or transmit signals (control signals, data, etc.) accordingly, whereby both one-way and two-way signal transport fall under the term "communication" in this context. The control device 100 does not necessarily have to be implemented by a central computing device or electronic control system; rather, decentralized and / or multi-level systems, control networks, cloud systems, and the like are included. The control device 100 can also be an integral part of a higher-level system control system or communicate with such a system.

[0060] If the heat pump 10 is operated simultaneously with the heat-absorbing process P2, the thermal storage units 30, 50 can be omitted. Figure 2 shows such an embodiment in which the process P1 is operated when energy, for example, renewable energy, is available while the heat pump 10 and the process P2 are running.

[0061] Alternatively, the thermal storage units 20, 40 on the other side can be omitted if the heat pump 10 is operated simultaneously with the heat-emitting process PI. Figure 3 shows such an embodiment, in which the process P2 is operated when energy, for example, renewable energy, is available while the heat pump 10 and the process PI are running.

[0062] The thermal storage devices 20, 30, 40, 50 are preferably designed as thermally insulated devices, such as insulated containers made of steel, concrete or temperature-resistant plastics and filled with water or thermal oil.

[0063] Thermal storage systems 20, 30, 40, 50 with a phase change can also be considered, or for example the salt storage systems commonly used in Concentrated Solar Power (CSP) or water-carrying pipes in solid concrete or bulk material (such as sand), whereby the concrete or the bulk material takes over the function of the thermal storage.

[0064] The heat TI released by the process PI for the system 1 proposed here is preferably in the range of 30 to 140°C, in particular in the range of 50 to 80°C. The required process heat T2 is preferably in the range of 70 to 250°C, in particular in the range of 90 to 140°C. Higher final temperatures are also contemplated, although in this case, additional components such as steam compressors or electrical heating elements may be required.

[0065] Figure 4 shows another embodiment of the

[0066] System 1, in which additional cooling of the cold emitted by the evaporator 11 of the heat pump 10 is implemented.

[0067] The heat pump 10 receives the waste heat at temperature TI, releases heat from a higher temperature T2 and simultaneously releases cold at temperature T3, i.e. T2 > TI > T3. The released cold is therefore below the temperature of the coolant outlet of the heat-releasing process PI. Depending on the design of the processes, further cooling of the cooling released at T3 by the evaporator 11 of the heat pump 10 to a temperature T3 ' < T3 may be useful. In the present exemplary embodiment, this is achieved by a cooling device 60 that is installed between the evaporator 11 and the thermal storage device 40. The cooling device 60 is implemented, for example, by air cooling, cooling with ambient water or another heat pump that is used for cooling. This enables even more effective cooling of the heat-releasing process PI.

[0068] In addition, the cold generated by the cooling device 60 can in principle also be used for other applications with a corresponding cooling requirement, such as data centers.

[0069] Figure 5 shows a further embodiment of the system 1, which enables an alternative use of cold discharge temperatures of the heat-absorbing process P2.

[0070] The heat-absorbing process P2 absorbs heat at a temperature of T2 and releases heat at a colder temperature level T4. If T4 is below the temperature level released by the evaporator 11 of the heat pump 10, then a circuit as shown in Figure 5 is advantageous, in which the colder temperature T4 (optionally via the thermal storage 40) is used to cool the heat-generating process P1. The temperature level T3 released by the evaporator 11 is used to generate the heat supply at T2.

[0071] Possible examples of heat-absorbing processes P2 with very low discharge temperature T4 include drying or DAC technologies with amine-based capture molecules.

[0072] A lower starting level is available for efficient cooling of the heat-emitting process PI and a higher starting level for heat generation, which allows the temperature increase to be achieved by the heat pump 10 to be limited. This advantageously saves operating energy.

[0073] In the configuration shown in Figure 5, the same heat medium must be used in both circuits. It is possible that different flows (volume per unit time) of the heat transfer medium through the evaporator 11 and condenser 12 are used in the design. This leads to different fill levels in the thermal storage units 20, 50 and 30, 40, so that in this case, measures should be taken to balance the quantities of the thermal storage units. This can be achieved using the control device 100 by a suitable, controlled pumping of heat medium between the thermal storage units 20, 30, 40, 50.

[0074] Here, the control device 100 again assumes control and / or regulation of the relevant processes. The control device 100 preferably also obtains information about the current values ​​of T4 and T3 and, in a further embodiment, can switch the circuit configuration between those shown in Figures 1 and 5. For this purpose, a corresponding switching valve 70 can be implemented, as shown in the embodiment of Figure 6.

[0075] A solution for heat coupling between intermittent and continuously operated processes P1, P2, or in other words, processes P1, P2 operated with different time frames, has been described. An example of this is an intermittently operated electrolysis process P1, such as an electrolyzer for the production of H2 or the direct reduction of CO2, and a DAC process for the production of CO2.

[0076] Processes P1, P2 often provide starting products that are then converted into the actual target substances in a large-scale synthesis process (e.g., methanol synthesis, reverse water gas shift reaction followed by a Fischer-Tropsch process). These large-scale synthesis processes typically run continuously, but the preceding processes P1, P2 sometimes run intermittently. In this case, it may be useful to provide product buffer storage 80, 90 before transfer to the subsequent synthesis process, as shown in the embodiment in Figure 7.

[0077] Preferably, for each intermittent process PI and / or P2, such a product buffer storage 80, 90 is provided for a subsequent continuously operated process. The product buffer storage 80, 90 should be dimensioned such that it can bridge downtimes of the volatile energies (a few hours to a few days). With only one intermittently operated process PI or P2, only one gas storage is required. A continuously operated process Pl, P2 requires no or only a significantly large product buffer storage 80, 90. Depending on the sensitivity of the process Pl, P2, direct coupling is also possible, or the use of a very small product buffer storage 80, 90 to compensate for process fluctuations (bridging times of, for example, 10 minutes to 1 hour).

[0078] As product buffer storage 80, 90, pressure storage devices made of metal or plastic, in particular fiber-reinforced plastic, are preferably used, which are preferably dimensioned so that process interruptions of hours to days can occur before the respective starting product runs out.

[0079] The control device 100 can additionally be supplied with information about the filling level of the product buffer stores 80, 90, so that the running times of the intermittently operated heat-emitting / heat-absorbing processes PI, P2 can be controlled such that the continuous supply of continuously operated subsequent processes is ensured via a sufficient filling level of the product buffer stores 80, 90.

[0080] The above-described embodiments of the system 1 of heat-coupled processes Pl, P2 can be applied to various industrial processes, including, for example, the process of producing synthetic fuels or energy carriers, which could be dimensioned as follows:

[0081] The starting point is the coupling of an industrial water electrolyzer with 17.5 MW of electrical power, whose waste heat is fed to a DAC plant with the aim of producing corresponding amounts of H2 and CO2, which can then be used for the synthesis of hydrocarbons (gasoline, methane, etc.).

[0082] Water electrolyzer: Intermittent operation (load factor 30%); 17.5 MW, 75% efficiency -> approx. 4.4 MWh waste heat at 65°C per hour; Produces approx. 335 kg H2 in 1 h of operation. Using this amount of hydrogen, it is possible to synthesize gasoline (approximate formula CgH 18) approximately 2,300 kg of CO2 are required. The synthesis of methanol (formula CH3OH) requires approximately 2,460 kg of CO2.

[0083] DAC: Continuous operation; approximately 2.78 MWh of heat is required to release 1t of CO2, resulting in the following heat quantities for the provision of the required CO2: approximately 6.39 MWh heat input for gasoline production; approximately 6.84 MWh heat input for methanol production.

[0084] The compressor's drive power must be added to the waste heat output. With a COP of 4, this results in approximately 5.5 MWh of heat at the high temperature level. COP (Coefficient of Performance) is defined as COP = generated heat at T2 [kWh] / required electrical power [kWh]. This results in a well-adapted system, as it is quite close to the heat output required by the DAC system. The smaller additional heat output required can be provided by other waste heat sources or by direct generation (electricity, gas, etc.). This results in a highly efficient overall system that ideally utilizes the fluctuating waste heat in the overall process.

[0085] The PI process for providing the waste heat source can be implemented in other ways besides the electrolyzer mentioned, for example via a data center, thermal power plant or a fuel cell.

[0086] To further minimize the operating costs of System 1, the integration of a battery storage system is recommended. This battery storage system is charged during peak times when the demand of heat pump 10 or System 1 is lower than the volatile energy generated. This system supplies the power to heat pump 10 (or other units) during periods of low energy generation. For example, with a solar PV system, the midday peak can be used to operate the units via the battery storage system in the morning and evening hours.

[0087] System 1 takes advantage of the fact that, unlike electricity, heat and / or process gases can be stored more cost-effectively and in a more resource-efficient manner. This allows processes P1 and P2 that run at different times (continuous and intermittent) to be advantageously coupled without placing excessive costs or resource burdens on the overall process.

[0088] System 1 enables the heat coupling of continuously operated and intermittently operated processes P1, P2. This allows flexible coordination with the use of temporarily available energy sources, such as renewable energies. System 1 allows adjustment of the temperature levels between the heat-emitting process P1 and the heat-absorbing process P2 by an energy-efficient heat pump 10, whose operating time can in turn be adapted to the availability of energy. The operating behavior can be optimized by control logic implemented by control device 100. Control device 100 can also implement monitoring functions. System 1 allows ideal waste heat utilization, for example, in the production of synthetic fuels or energy sources.

[0089] Where applicable, all individual features presented in the embodiments may be combined and / or exchanged without departing from the scope of the invention.

[0090] List of reference symbols

[0091] I System

[0092] 10 heat pump

[0093] II Evaporator

[0094] 12 Capacitor

[0095] 20 Thermal storage / Tl storage

[0096] 30 Thermal storage / T2 storage

[0097] 40 Thermal storage / T3 storage

[0098] 50 Thermal storage / T4 storage

[0099] 60 Cooling device

[0100] 70 changeover valve

[0101] 80 product buffer storage

[0102] 90 product buffer storage

[0103] 100 control device

[0104] PI Heat-emitting process equipment

[0105] P2 Heat-absorbing process device

[0106] E Facility for providing electrical energy

[0107] TI waste heat of the heat-emitting process

[0108] T2 Input heat of the heat-absorbing process

[0109] T3 Temperature level of cold release

[0110] T4 Waste heat from the heat-absorbing process

Claims

Claims 1. System (1) for heat-coupled processes, the system (1) comprising: at least one heat-emitting process device (PI) configured to carry out a technical process and thereby release waste heat at a temperature TI; at least one heat-absorbing process device (P2) configured to carry out a technical process and thereby absorb heat at a temperature T2 higher than TI; a heat pump (10) configured to raise the waste heat of the heat-emitting process device (PI) from TI to T2;and a Tl storage device (20), which is a thermal storage device, is arranged between the heat-emitting process device (PI) and the heat pump (10) and is set up to store the waste heat of the heat-emitting process device (PI), preferably at the temperature T1, and / or a T2 storage device (30), which is a thermal storage device, is arranged between the heat pump (10) and the heat-absorbing process device (P2) and is set up to store the heat to be absorbed by the heat-absorbing process device (P2), preferably at the temperature T2.; 2. System (1) according to claim 1, characterized in that the heat pump (10) is designed to deliver cold of a temperature T3 and to supply it to the heat-emitting process device (PI), wherein preferably a T3 storage (40), which is a thermal storage, is arranged between the heat pump (10) and the heat-emitting process device (PI) and is designed to store the cold emitted by the heat pump (10), preferably at temperature T3.

3. System (1) according to claim 2, characterized in that the system (1) comprises a cooling device (60) which is arranged between the heat pump (10) and the heat-emitting process device (PI) or the T3 storage (40) and is designed to cool the cold emitted by the heat pump (10) at T3 to a lower temperature T3 '.

4. System (1) according to one of the preceding claims, characterized in that the heat-absorbing process device (P2) is designed to release waste heat of a temperature T4 and to supply it to the heat pump (10), wherein preferably a T4 storage device (50), which is a thermal storage device, is arranged between the heat-absorbing process device (P2) and the heat pump (10) and is designed to store the waste heat released by the heat-absorbing process (P2), preferably at the temperature T4.

5. System (1) according to claim 4, characterized in that the waste heat on T4 of the heat-absorbing process device (P2) or the T4 storage (50) can be supplied to the heat-emitting process device (PI) or the T3 storage for cooling, bypassing the heat pump (10), preferably switchable by means of a switching valve (70).

6. System (1) according to claim 5, characterized in that the cold at T3 of the heat pump (10) can be fed to the T4 storage, preferably switchable by means of the switching valve (70).

7. System (1) according to one of the preceding claims, characterized in that at least one product buffer (80, 90) is provided, which is designed to Starting product of at least one of the process devices (Pl, P2) to be stored.

8. System (1) according to one of the preceding claims, characterized in that the heat-emitting process device (PI) and / or the heat-absorbing process device (P2) and / or the heat pump (10) draw electrical energy for regular operation.

9. System (1) according to one of the preceding claims, characterized in that the heat-emitting process device (PI) and / or the heat-absorbing process device (P2) and / or the heat pump (10) operate intermittently.

10. System (1) according to one of the preceding claims, characterized in that a control device (100) is further provided for controlling and / or regulating the system (1), wherein the control device (100) is preferably set up to obtain information about the filling states of the thermal storage devices (20, 30, 40, 50) and to control the heat pump (10) in such a way that sufficient process heat is always available for the heat-absorbing process device (P2).

11. System (1) according to one of the preceding claims, characterized in that the heat-emitting process device (PI) is an electrolyzer for generating H2 or directly reducing CO2 and / or the heat-absorbing process device (P2) is configured to carry out a DAC process for providing CO2.

12. A method for operating a system (1) of heat-coupled processes, the method comprising: Carrying out a technical process which releases waste heat at a temperature TI by means of a heat-emitting process device (PI); Carrying out a technical process which absorbs heat at a temperature T2 higher than TI by means of a heat-absorbing process device (P2); Raising the waste heat of the heat-emitting process from TI to T2 by means of a heat pump (10); Storing the waste heat of the heat-emitting process in a Tl storage (20), which is a thermal storage and is arranged between the heat-emitting process device (PI) and the heat pump (10), and / or Storing the heat to be absorbed by the heat-absorbing process in a T2 storage device (30), which is a thermal storage device and is arranged between the heat pump (10) and the heat-absorbing process device (P2).

13. Method according to claim 12, characterized in that the heat-emitting process and the heat-absorbing process are at least temporarily not carried out simultaneously.

14. The method according to claim 12 or 13, characterized in that the heat pump (10) releases cold at a temperature T3 and supplies it to the heat-emitting process device (PI), wherein preferably a T3 storage device (40), which is a thermal storage device, is arranged between the heat pump (10) and the heat-emitting process device (PI) and stores the cold released by the heat pump (10), preferably at the temperature T3.

15. Method according to one of claims 12 to 14, characterized in that the heat-absorbing process device (P2) releases waste heat of a temperature T4 and supplies it to the heat pump (10), wherein preferably a T4 storage (50), which is a thermal Storage is arranged between the heat-absorbing process device (P2) and the heat pump (10) and stores the waste heat emitted by the heat-absorbing process (P2), preferably at temperature T4.

Citation Information

Patent Citations

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    EP1614980A2

  • Combined heating power and cooling apparatus with energy storage type adapted to an active distribution network and its method

    US20170131037A1