AT528577A4 - Electrochemical system and method for operating an electrochemical system - Google Patents

Abstract

The present invention relates to an electrochemical system (100) for power generation or electrolysis, comprising a media supply area (10) for supplying media (40), wherein the media (40) comprise a reactant (42) and air (44), a cell stack (30) comprising several electrochemical cells (32), and a media feed area (20) for temperature-controlling the media (40) and for conveying the media (40) from the media supply area (10) to the cell stack (30). The media feed area (20) comprises at least two heat exchangers (62, 64) and at least two electric heaters (22, 24) for indirectly heating a reactant feed (28) comprising the reactant (42) in two stages.

Description

Description

ELECTROCHEMICAL SYSTEM AND METHOD FOR OPERATING AN ELECTROCHEMICAL SYSTEM

[0001] The present invention relates to an electrochemical system for generating electricity or for electrolysis and to a method for operating an electrochemical system for controlling the temperature of a reactant inflow.

[0002] Electrochemical systems for power generation or electrolysis are known in the prior art. Solid oxide fuel cells (SOFCs) require a very high temperature to maintain the electrochemical conversion until they reach their thermoneutral operating point. At the thermoneutral operating point, power can be generated efficiently, and excess heat can be supplied via the exothermic oxidation of various gases as reactants.

[0003] Typically, complex heating conditions are preset to meet the various requirements of a cell stack of an electrochemical system. Furthermore, during operation at high temperatures, the reactants are fed into the electrochemical cells of the cell stack because there are limitations due to thermal or chemical stresses in the reactive layers of the electrochemical cells.

[0004] In so-called high-temperature co-electrolysis (Co-Solid Oxide Electrolyzer Cell: Co-SOEC; parallel H2O & CO2 high-temperature co-electrolysis), the reactants are also supplied to the electrolysis cells at high temperatures, whereby the carbon dioxide CO2 can originate from various sources (direct air capture, biogas processes, industrial exhaust gases, etc.). The water H2O must be in vapor form. Depending on the CO2 content and operating point, heat is also required for this process.

[0005] Consequently, heating and maintaining a high operating temperature of SOFC/SOEC systems is crucial for their operability, lifetime, and sustainability.

[0006] Against this background, one object of the present invention is to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to provide an electrochemical system in which the heating of a reactant inflow is improved and which is flexible with regard to the reactants used and the mode of operation (current generation or electrolysis).

[0007] The foregoing problems are solved by an electrochemical system with the features of claim 1 and a method for operating an electrochemical system with the features of claim 10. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the electrochemical system according to the invention naturally also apply in connection with the method according to the invention for operating an electrochemical system, and vice versa, so that the disclosure regarding the individual aspects of the invention always refers, or can refer, to each other.

[0008] Accordingly, an electrochemical system for power generation or electrolysis is described. The electrochemical system comprises a media supply area for supplying media, wherein the media consist of a reactant and air, a cell stack comprising several electrochemical cells, and a media feed area for temperature control of the media and for conveying the media from the media supply area to the cell stack. The media feed area includes at least two heat exchangers and at least two electric heaters for indirectly heating a reactant feed comprising the reactant in two stages.

[0009] By providing at least two heat exchangers and at least two electric heaters for indirectly heating the reactant inflow, the reactant inflow can be-

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The current can be used to heat the system indirectly, thus allowing for flexible configuration of the electrochemical system.

[0010] Accordingly, the choice of media can be flexible. The media can be, on the one hand, the reactant and, on the other hand, air. The media can therefore contain both the reactant and air. The reactant can include hydrogen (H₂), water (H₂O), carbon monoxide (CO), carbon dioxide (CO₂), and/or methane (CH₄), and/or other hydrocarbons. Furthermore, nitrogen (N₂) and/or a protective gas can be added to the reactant. This can be advantageous during the start-up and stop-down processes of the electrochemical system.

[0011] The electrochemical system can be used, among other things, as a solid oxide fuel cell (SOFC), a solid oxide electrolyzer cell (SOEC), or a solid oxide co-electrolyzer cell (Co-SOEC) under real-world conditions. Likewise, the electrochemical system can also be used, among other things, as an SOFC, SOEC, or Co-SOEC test environment to test individual components, such as the cell stack. The electrochemical system allows for flexible configuration of the media supplied to the cell stack and flexible configuration of the operating mode, i.e., fuel cell or electrolyzer cell.

[0012] Furthermore, the combination of heat exchangers and electric heaters for indirect heating of the reactant inflow together with the reactant, water vapor and air supply allows a flexible configuration for the media and the operating mode.

[0013] The present invention contributes to the prior art by providing a more flexible and simpler infrastructure that enables efficient connection of the media to the cell stack. This can shorten installation and commissioning times and thereby facilitate efficient testing. Simplicity and flexibility are paramount in the present invention. Accordingly, no afterburner or heat exchanger is used for the exhaust gas flows of the cell stack. Furthermore, the setup of the present invention does not include an oil bath heat exchanger or a bypass path.

[0014] A stage can be a location where the reactant inflow is heated. Accordingly, the reactant inflow can be heated in two stages, i.e., at two different locations.

[0015] The electrochemical system can be a fuel cell system for generating electricity with at least one fuel cell stack or an electrolysis system for electrolysis with at least one electrolysis cell stack.

[0016] According to an embodiment of the electrochemical system, the media supply area has a first electric heater for heating a first air stream and a first heat exchanger to heat the reactant flow to the cell stack by means of the first heat exchanger and the first air stream in a first stage.

[0017] Advantageously, the reactant inflow is indirectly heated by means of the first electric heater. The first airflow is heated by means of the first electric heater. Subsequently, the first airflow is passed through the first heat exchanger and releases its heat to the reactant inflow there.

[0018] According to a further embodiment of the electrochemical system, the media supply area has a second electric heater for heating a second air stream and a second heat exchanger to heat the reactant inflow to the cell stack by means of the second heat exchanger and the second air stream in a second stage.

[0019] Advantageously, the reactant inflow is indirectly heated by means of the second electric heater. The second airflow is heated by means of the second electric heater. Subsequently, the second airflow is passed through the second heat exchanger and transfers its heat to the reactant inflow there.

[0020] In this process, the heating of the reactant inflow is carried out by means of the second heat exchanger.

in the direction of the reactant inflow downstream of the first heat exchanger. The heating of the reactant inflow takes place in two stages, with the first stage heating the reactant inflow by means of the first heat exchanger in the direction of the reactant inflow before the second stage heating the reactant inflow by means of the second heat exchanger.

[0021] According to a further embodiment of the electrochemical system, the media supply area has a third electric heater for heating an air stream for supplying the cell stack. The air stream is heated directly by means of the third electric heater. This allows for a very simple design. Alternatively, it can also be advantageous if the air stream to the cell stack is heated indirectly.

[0022] According to a further embodiment of the electrochemical system, the media supply area has a third electric heater for heating a third air stream and a third heat exchanger to heat an air stream to the cell stack by means of the third heat exchanger and the third air stream. The air stream is heated only indirectly by means of the electric heater.

[0023] According to a further embodiment of the electrochemical system, the electric heaters have built-in temperature sensors. These are arranged and designed specifically for component protection. Advantageously, however, this also allows the desired temperature of the corresponding air streams to be precisely set.

[0024] According to a further embodiment of the electrochemical system, the media supply area has a reactant line for conveying reactant to the first heat exchanger and a reactant line heat band, wherein the reactant line is surrounded by the reactant line heat band to prevent condensation in the reactant line.

[0025] The reactant line heat wrap serves to insulate the reactant line. By insulating the reactant line, condensation in the reactant line can be avoided or at least reduced.

[0026] According to a further embodiment of the electrochemical system, the media supply area has a steam line for conveying steam to the first heat exchanger and a steam line heating band, wherein the steam line is surrounded by the steam line heating band to prevent condensation in the steam line.

[0027] The steam pipe insulation tape serves to insulate the steam pipe. By insulating the steam pipe, condensation in the steam pipe can be prevented or at least reduced.

[0028] According to a further embodiment of the electrochemical system, the electrochemical system has a separate reactant exhaust line and a separate air exhaust line. The reactant exhaust line and the air exhaust line are not connected to each other and both terminate in an exhaust outlet. The exhaust outlet can be located in the media supply area. Because the two main exhaust lines are not connected to each other, flexible operation is possible.

[0029] Furthermore, a method for operating an electrochemical system for controlling the temperature of a reactant inflow, comprising a reactant for supplying a cell stack of the electrochemical system, is described. The method comprises the following steps:

[0030] Heating a first airflow by means of a first electric heater or via a heat exchanger,

[0031] Heating the reactant inflow by means of a first heat exchanger, wherein the first airflow is passed through the first heat exchanger to transfer heat to the reactant inflow,

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[0032] Heating a second airflow by means of a second electric heater, and

[0033] Heating the reactant inflow by means of a second heat exchanger, wherein the second airflow is passed through the second heat exchanger to transfer heat to the reactant inflow.

[0034] Advantageously, the reactant flow is heated in two successive stages. The heating of the reactant flow by means of the first heat exchanger constitutes the first heating stage. Furthermore, the heating of the reactant flow by means of the second heat exchanger constitutes the second heating stage.

[0035] A further advantage is that the reactant inflow is indirectly heated by means of the electric heaters. The actual heating of the reactant inflow is carried out by means of the heat exchangers. The electric heaters represent the active elements, since the actual heating power is provided here. The heat exchangers, on the other hand, can be passive elements. The temperature of the reactant inflow can be indirectly controlled via the electric heaters.

[0036] According to one embodiment of the method, the temperatures of the air streams are controlled by means of temperature sensors in the electric heaters. For this purpose, the temperature of the air streams can be continuously measured by means of the temperature sensors and the heating power of the electric heaters can then be controlled accordingly.

[0037] Alternatively or additionally, the temperature of the reactant inflow can be measured. The temperature of the reactant inflow can then be used to pre-control the electric heaters accordingly.

[0038] According to a further embodiment of the method, the method includes the following additional step: heating an air supply for feeding to the cell stack by means of a third electric heater. Accordingly, the air supply is heated directly by means of the third electric heater.

[0039] According to a further embodiment of the method, the method comprises the following additional steps: heating a third airflow by means of a third electric heater, and heating an airflow to the cell stack by means of a third heat exchanger, wherein the third airflow is passed through the third heat exchanger to transfer heat to the airflow. Accordingly, the airflow is only heated indirectly by means of the third electric heater.

[0040] According to a further embodiment of the method, a reactant supplied to the reactant flow is controlled by at least one mass flow controller with an integrated proportional solenoid valve. The respective proportional solenoid valve is normally closed for safety reasons and is opened during operation if no control of the proportional solenoid valve is available for any reason.

[0041] Other possible implementations of the invention also include combinations of features not explicitly mentioned above or below with regard to the exemplary embodiments. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0042] Further advantages, features and details of the invention will become apparent from the following description, in which exemplary embodiments are described in detail with reference to the drawings. The drawings show:

[0043] Fig. 1 shows a schematic view of an electrochemical system; and

[0044] Fig. 2 shows a flowchart of a method for operating an electrochemical system.

[0045] Fig. 1 shows a schematic view of an electrochemical system 100 for power generation or electrolysis. The electrochemical system 100 can be, among other things, a SOFC, SOEC, or Co-SOEC system. In particular, the electrochemical system 100 can be a test system for testing individual components of the system.

The electrochemical system 100 has a media supply area 10, a cell stack 30 and a media feed area 20.

[0046] The cell stack 30 comprises several electrochemical cells 32, a cell stack reactant inlet 72, a cell stack reactant outlet 74, a cell stack air inlet 76 and a cell stack air outlet 78.

[0047] The media supply area 10 comprises the media 40. The media 40 can include at least one reactant 42, nitrogen N2, a protective gas 98, water 38, and air 44. The reactant 42 can include hydrogen H2, carbon monoxide CO, carbon dioxide CO2, and/or methane CH4. All the different media can be stored in separate storage tanks. The media supply area 10 can additionally include a power supply 12, an air outlet 14, and an exhaust outlet 16.

[0048] The media supply area 20 serves to temper the media 40 and to direct the media 40 from the media supply area 10 to the cell stack 30. For this purpose, the media supply area 20 has at least two heat exchangers 62, 64 and at least two electric heaters 22, 24. A reactant inflow 28 comprising the reactant 42 is indirectly heated in two stages by means of the heat exchangers 62, 64 and the electric heaters 22, 24.

[0049] As shown in Fig. 1, the reactant inflow 28, comprising the reactant 42, is directed via the first heat exchanger 62 and then via the second heat exchanger 64 to the cell stack reactant inlet 72 of the cell stack 30. The first airflow 52 is passed through the first electric heater 22 and heated by it. The heated airflow 52 is then passed through the first heat exchanger 62 and transfers its heat to the reactant inflow 28. The first stage of heating the reactant inflow 28 takes place at the first heat exchanger 62.

[0050] The second airflow 54 is passed through the second electric heater 24 and heated by it. The heated second airflow 54 is then passed through the second heat exchanger 64, where it transfers its heat to the reactant inflow 28. The second stage of heating the reactant inflow 28 takes place in the second heat exchanger 64, since the second heat exchanger 64 is located downstream of the first heat exchanger 62 in the direction of the reactant inflow 28.

[0051] As can be seen in Fig. 1, the media supply area 20 additionally has a third electric heater 26. By means of the third electric heater 26, the air supply 56, which is supplied to the cell stack air inlet 76, is heated. The air supply 56 is thus heated directly.

[0052] Alternatively, as not shown in Fig. 1, the media supply area 20 could include a third electric heater 26 for heating a third airflow and a third heat exchanger. The airflow 56 to the cell stack 30 could then be heated by means of the third heat exchanger and the third airflow. Here, the airflow 56 is heated only indirectly.

[0053] All electric heaters 22, 24, 26 can have built-in temperature sensors for controlling the temperature of the electric heaters 22, 24, 26. This allows the corresponding air streams 52, 54, 54 to be tempered as desired.

[0054] The air 44, which may be compressed air, is passed through an air pressure valve 80 and then divided into the first air stream 52, the second air stream 54, and the air supply stream 56. Additionally, a first air valve 82 may be arranged in the first air stream 52, a second air valve 84 in the second air stream 54, and a third air valve 86 in the air supply stream 56. Furthermore, the air pressure valve 80, the first air valve 82, the second air valve 84, and the third air valve 86 may be arranged in the media supply area 10.

[0055] Furthermore, the air 44 can also be directed via a vent valve 60 and an element 92 to the first air stream 52, to the second air stream 54 and to the air inlet 56.

The vent valve 60 and the element 92 can be arranged in the media supply area 10.

[0056] The various reactants 42 and the nitrogen N2 can each be guided through a mass flow controller 50 and can be introduced into the reactant line 46 via a mixer M. This allows the mass flow controllers 50 to determine how much of each reactant 42 and how much nitrogen N2 are present in the reactant inflow 28.

[0057] Each mass flow controller 50 can have an integrated proportional solenoid valve to control the respective mass flow. For safety reasons, the respective integrated proportional solenoid valve is normally closed and opens during operation. This is the case as long as no control signals are sent to the integrated proportional solenoid valve.

[0058] A protective gas 98 can also be fed into the reactant line 46 via a vent valve 18 and an element 94 via the mixer M.

[0059] The vent valve 18 and element 94, as well as the exhaust outlet 16 and element 92, are specifically designed as venting paths and vent valves, which are used in the event of an emergency shutdown of the system. The vent valve 18 and the exhaust outlet 16 are closed during normal operation but are opened during non-power operation. Elements 92 and 94 are preferably designed as mechanical rotameters, which are configured to protect the system even in the event of a failure, allowing the system to be shut down in a controlled manner.

[0060] The media supply area 10 can further comprise a water tank for water 38, a water pump 70, and a water flow measuring device 90. The water pump 70 can pump the water 38 from the water tank, through the water flow measuring device 90, to the water evaporator 96. The water flow measuring device 90 can be used to regulate the pumping speed of the water pump 70. As shown in Fig. 1, the water evaporator 96 is arranged in the media supply area 20. Alternatively, the water evaporator 96 could also be arranged in the media supply area 10.

[0061] The steam exiting the water evaporator 96 is directed via the steam line 66 to a mixer M. The reactant line 46 also leads into this mixer M. The reactant inflow 28 is directed from this mixer M.

[0062] The reactant line 46 can be surrounded by a reactant line heating band 48. This can prevent or at least reduce condensation within the reactant line 46. Likewise, the steam line 66 can be surrounded by a steam line heating band 68. This can prevent or at least reduce condensation within the steam line 66.

[0063] After passing through the heat exchangers 62, 64, the first airflow 52 and the second airflow 54 are combined by means of a mixer M and directed to the air outlet 14.

[0064] The cell stack 30, in particular the several electrochemical cells 32, can be supplied with power via the power supply 12.

[0065] The electrochemical system 100 has a separate reactant exhaust line 34, which leads from the cell stack reactant outlet 74 to the exhaust outlet 16, and a separate air exhaust line 36, which leads from the cell stack air outlet 78 to the exhaust outlet 16. A reactant exhaust line backflow preventer 104 can be arranged in the reactant exhaust line 34. Furthermore, an air exhaust line backflow preventer 106 can be arranged in the air exhaust line 36.

[0066] Fig. 2 shows a flowchart of a method for operating an electrochemical system 100. In particular, the temperature of the reactant inflow 28 comprising the reactant 42 can be controlled by means of this method. The reactant inflow 28 serves to supply the cell stack 30 of the electrochemical system 100. The method

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exhibits the following steps:

[0067] In a first step S1, a first airflow 52 is heated by means of a first electric heater 22.

[0068] In a second step S2, the reactant inflow 28 is heated by means of a first heat exchanger 62. For this purpose, the first airflow 52 is passed through the first heat exchanger 62 to transfer heat to the reactant inflow 28.

[0069] In a third step S3, a second air stream 54 is heated by means of a second electric heater 24.

[0070] In a fourth step S4, the reactant inflow 28 is heated by means of a second heat exchanger 64. For this purpose, the second airflow 54 is passed through the second heat exchanger 64 to transfer heat to the reactant inflow 28.

[0071] The steps S1 to S4 do not have to be performed in the specified order.

REFERENCE MARK LIST

10 Media supply area

12 Power supply

14 Air outlet

16 Exhaust outlet

18 Vent valve

20 Media feed area

22 first electric heater

24 second electric heater

26 third electric heater

28 Reactant influx

30 cell stacks

32 several electrochemical cells 34 reactant exhaust line

36 Air exhaust pipe

38 Water

40 Medium

42 Reactant

44 Air

46 Reactant line

48 Reactant line heating tape 50 Mass flow controller

52 first airflow

54 second airflow

56 Airflow

60 Vent valve

62 first heat exchanger

64 second heat exchanger

66 Water vapor line

68 Water vapor line heating tape

Water pump, cell stack reactant inlet, cell stack reactant outlet, cell stack air inlet, cell stack air outlet, air pressure valve

first air valve

second air valve

third air valve 86 water flow measuring device element

element

Water evaporator

Inert gas

electrochemical system reactant exhaust line backflow valve

Air/exhaust pipe backflow preventer

Mixer

AT 528 577 A4 2026-03-15

Patent claims

1. Electrochemical system (100) for generating electricity or for electrolysis, comprising

a media supply area (10) for supplying media (40), wherein the media (40) comprise a reactant (42) and air (44),

a cell stack (30) comprising several electrochemical cells (32), and

a media feed area (20) for tempering the media (40) and for directing the media (40) from the media supply area (10) to the cell stack (30),

characterized in that the media supply area (20) has at least two heat exchangers (62, 64) and at least two electric heaters (22, 24) for indirectly heating a reactant inflow (28) comprising the reactant (42) in two stages.

2. Electrochemical system (100) according to claim 1, characterized in that the media supply area (20) has a first electric heater (22) for heating a first air stream (52) and a first heat exchanger (62) to heat the reactant inflow (28) to the cell stack (30) by means of the first heat exchanger (62) and the first air stream (52) in a first stage.

3. Electrochemical system (100) according to claim 2, characterized in that the media supply area (20) has a second electric heater (24) for heating a second air stream (54) and a second heat exchanger (64) to heat the reactant inflow (28) to the cell stack (30) by means of the second heat exchanger (64) and the second air stream (54) in a second stage.

4. Electrochemical system (100) according to one of the preceding claims, characterized in that the media supply area (20) has a third electric heater (26) for heating an air supply (56) for supplying to the cell stack (30).

5. Electrochemical system (100) according to one of claims 1 to 3, characterized in that the media supply area has a third electric heater (26) for heating a third air stream and a third heat exchanger to heat an air supply (56) to the cell stack (30) by means of the third heat exchanger and the third air stream.

6. Electrochemical system (100) according to one of the preceding claims, characterized in that the electric heaters (22, 24, 26) have built-in temperature sensors.

7. Electrochemical system (100) according to one of the preceding claims, characterized in that the media supply area (20) has a reactant line (46) for conveying reactant (42) to the first heat exchanger (62) and a reactant line heating band (48), wherein the reactant line (46) is surrounded by the reactant line heating band (48) to prevent condensation in the reactant line (46).

8. Electrochemical system (100) according to one of the preceding claims, characterized in that the media supply area (20) has a steam line (66) for conveying steam to the first heat exchanger (62) and a steam line heating band (68), wherein the steam line (66) is surrounded by the steam line heating band (68) to prevent condensation in the steam line (66).

9. Electrochemical system (100) according to one of the preceding claims, characterized in that the electrochemical system (100) has a separate reactant exhaust line (34) and a separate air exhaust line (36).

10. Method for operating an electrochemical system (100) for controlling the temperature of a reactant inflow (28) comprising a reactant (42) for supplying a cell stack (30) of the electrochemical system (100), characterized by the

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Steps:

Heating a first airflow (52) by means of a first electric heater (22),

Heating the reactant inflow (28) by means of a first heat exchanger (62), wherein the first airflow (52) is passed through the first heat exchanger (62) to transfer heat to the reactant inflow (28),

Heating a second airflow (54) by means of a second electric heater (24), and

Heating the reactant inflow (28) by means of a second heat exchanger (64), wherein the second airflow (54) is passed through the second heat exchanger (64) to transfer heat to the reactant inflow (28).

11. Method according to claim 10, characterized in that the temperatures of the air streams (52, 54) are controlled by means of temperature sensors in the electric heaters (22, 24).

12. Method according to claim 10 or 11, characterized by the further step of: heating an air inflow (56) for supply to the cell stack (30) by means of a third electric heater (26).

13. Method according to claim 10 or 11, characterized by the further steps of: heating a third air stream by means of a third electric heater (26), and

Heating an air inflow (56) to the cell stack (30) by means of a third heat exchanger, wherein the third airflow is passed through the third heat exchanger to transfer heat to the air inflow (56).

14. Method according to one of claims 10 to 13, characterized in that a reactant (42) supplied to the reactant inflow (28) is controlled via at least one mass flow controller (50) with integrated proportional solenoid valve.

This includes 2 sheets of drawings

Claims (9)

New patent claims 1. Electrochemical system (100) for generating electricity or for electrolysis, comprising a media supply area (10) for supplying media (40), wherein the media (40) comprise a reactant (42) and air (44), a cell stack (30) comprising several electrochemical cells (32), and a media feed area (20) for tempering the media (40) and for directing the media (40) from the media supply area (10) to the cell stack (30), wherein the media supply area (20) comprises at least two heat exchangers (62, 64) and at least two electric heaters (22, 24) for indirectly heating a reactant inflow (28) comprising the reactant (42) in two stages, wherein the media supply area (20) comprises a first electric heater (22) for heating a first airflow (52) and a first heat exchanger (62) for heating the reactant inflow (28) to the cell stack (30) by means of the first heat exchanger (62) and the first airflow (52) in a first stage, wherein the media supply area (20) comprises a second electric heater (24) for heating a second airflow (54) and a second heat exchanger (64) for heating the reactant inflow (28) to the cell stack (30) by means of the second heat exchanger (64) and the second airflow (54) to heat up in a second stage, characterized in that the media supply area (20) has a third electric heater (26) for heating an air supply (56) for supplying to the cell stack (30). 2. Electrochemical system (100) according to claim 1, characterized in that the electric heaters (22, 24, 26) have built-in temperature sensors. 3. Electrochemical system (100) according to one of the preceding claims, characterized in that the media supply area (20) has a reactant line (46) for conveying reactant (42) to the first heat exchanger (62) and a reactant line heating band (48), wherein the reactant line (46) is surrounded by the reactant line heating band (48) to prevent condensation in the reactant line (46). 4. Electrochemical system (100) according to one of the preceding claims, characterized in that the media supply area (20) has a steam line (66) for conveying steam to the first heat exchanger (62) and a steam line heating band (68), wherein the steam line (66) is surrounded by the steam line heating band (68) to prevent condensation in the steam line (66). 5. Electrochemical system (100) according to one of the preceding claims, characterized in that the electrochemical system (100) has a separate reactant exhaust line (34) and a separate air exhaust line (36). 6. Method for operating an electrochemical system (100) for controlling the temperature of a reactant inflow (28) comprising a reactant (42) for supplying a cell stack (30) of the electrochemical system (100), characterized by the steps: Heating a first airflow (52) by means of a first electric heater (22), Heating the reactant inflow (28) by means of a first heat exchanger (62), wherein the first airflow (52) is passed through the first heat exchanger (62) to transfer heat to the reactant inflow (28), Heating a second airflow (54) by means of a second electric heater (24), and Heating the reactant inflow (28) by means of a second heat exchanger (64), wherein the second airflow (54) is passed through the second heat exchanger (64) to transfer heat to the reactant inflow (28), LATEST CLAIMS MADE Heating a third airflow by means of a third electric heater (26), and Heating an air inflow (56) to the cell stack (30) by means of a third heat exchanger, wherein the third airflow is passed through the third heat exchanger to transfer heat to the air inflow (56). 7. Method according to claim 6, characterized in that the temperatures of the air streams (52, 54) are controlled by means of temperature sensors in the electric heaters (22, 24). 8. Method according to claim 6 or 7, characterized by the further step of: heating an air inflow (56) for supply to the cell stack (30) by means of a third electric heater (26). 9. Method according to one of claims 6 to 8, characterized in that a reactant (42) supplied to the reactant inflow (28) is controlled via at least one mass flow controller (50) with integrated proportional solenoid valve. 16 / 16 LATEST CLAIMS MADE