Treatment plant for treating workpieces, and method for treating workpieces

Abstract

The present invention relates to a treatment plant (100) for treating workpieces, in particular a drying plant (102) for drying vehicle bodies, comprising: at least one treatment chamber (104) which comprises one or several treatment chamber sections (105), wherein the at least one treatment chamber (104) and / or the one or several treatment chamber sections (105) are each assigned to one of several separate air circulation modules (106), and wherein each air circulation module (106) is arranged to guide a separate cyclical gas flow; and a heat carrier system (120) for indirectly heating the gas flows, which comprises a heating device (124), wherein a) at least one air circulation module (106) has a heat transfer device (144) by means of which the respective air circulation module (106) is coupled to the heat carrier system (120); and / or b) several air circulation modules (106) are incorporated into one or more heating circuits (160), in particular heating gas circuits, which are coupled to the heat carrier system (120) via a central heat transfer device (158). The present invention further relates to a method for treating workpieces.

Description

[0001] Treatment system for treating workpieces and method for treating workpieces

[0002] The present invention relates to a treatment system for treating workpieces. Furthermore, the invention relates to a method for treating workpieces.

[0003] It is known from practice that, in the course of combating global warming, more and more automobile manufacturers are considering converting existing treatment plants, such as drying plants for vehicle bodies, from fossil fuels such as gas, petroleum, etc. to heating using electrical energy from renewable energy sources.

[0004] It is known that up to now, a combination of heat provision and exhaust air cleaning has predominated in the heating of such drying systems or dryers, whereby the residual heat still present in the cleaned dryer exhaust air or the clean gas is transferred to the dryer atmosphere, i.e. the recirculating air and / or the fresh gas or the fresh air, by means of heat exchangers - usually connected in series - without the two media being mixed.

[0005] When converting or upgrading a drying plant from fossil to electric heating, it is common practice to use decentralized electrical heat sources to heat the recirculation and fresh air modules, also known as recirculation and fresh air units, and thus to utilize the possibilities of direct electrical heating, whereby each recirculation and fresh air module is usually equipped with its own heating register.

[0006] Direct heating converts electrical energy into thermal energy, or heat, by flowing the electrical current through a resistive heating coil, heating wire, or similar element. The thermal energy is transferred directly to the gas stream to be tempered, such as the recirculating air stream or the fresh air stream, via heat conductors such as heating fins. The dryer exhaust air is cleaned independently of the dryer heating system. Thermal processes are typically used to clean the solvent-containing and odorous exhaust air.

[0007] As part of the electrification process, these cleaning processes are now also brought to operating temperature using electrical energy. Once the system reaches the required operating temperature, often – depending on the solvent load – only the heat energy released by the oxidation of solvents is required to achieve self-sufficient and autothermal operation of the exhaust air cleaning system.

[0008] However, the specification and installation of decentralized electric heating registers in the individual recirculation and fresh air modules means that heat sources using sustainable energy sources such as hydrogen, biogas, solar thermal energy, pellets, etc. are not interchangeable for dryer heating. The parallel provision or parallel use of several different heat sources in a so-called hybrid mode is also not possible with decentralized electric direct heating.

[0009] The parallel use or at least the provision of several options is a decisive advantage, especially in times of the energy transition, since many operators of drying plants or similar systems cannot yet foresee which form of energy will be the energy of the future for their location.

[0010] Furthermore, the concept of dryer heating with decentralized electrical heat sources such as heating registers requires a significant amount of space. Control cabinets with the necessary power controls (e.g., thyristors) for the individual heating registers must be installed.

[0011] In addition, transformer substations must be installed to supply power to the individual heat sources. Since the conversion from the medium-voltage level (with small cable cross-sections) to the low-voltage level ideally takes place where the electrical energy is needed, i.e., at the decentralized heat sources, this creates a need for installation space that often cannot be met in existing systems due to the limited building space. If it is not possible to install the substations near the consumers, i.e., the heat sources, large and expensive cable cross-sections are required at the low-voltage level to avoid excessive power losses.

[0012] In addition, the current concept of dryer heating with decentralized electrical heating registers requires a high level of power cabling, as each unit or register must be connected separately.

[0013] In this context, the associated power losses (cable and control cabinet losses) should not be ignored. In a drying system for vehicle bodies with an exemplary throughput of 31 units per hour, these can add up to 173 kW, or approximately 11% of the total power. These high electrical losses contradict the original sustainability concept underlying the conversion. While these power losses can be partially counteracted by using larger cable cross-sections, this entails higher investment costs.

[0014] Another disadvantage is that the total connected load of the individual electrical heating sources or heating registers is usually higher (by approximately 10%) than in the case of a central solution with only a single heating source.

[0015] In the case of a single heat source, the power requirement of a dryer or drying system, which hardly differs from the heating-up case with a heat-up time of only two to three hours in operation or production, can be covered by this one heat source in both operating modes.

[0016] In comparison, at the section or zone level, i.e., when individual sections or zones of the dryer are heated separately, there are significant differences between the two modes "heating up" and "operation or hold." For example, during heating up sections, the power requirement is generally higher during operation than during heating up, and the opposite is true for hold sections.

[0017] Consequently, in a decentralized electrical solution, the electrical heating registers must be dimensioned according to the greater heating output of the operating or heating-up case, since each dryer section is heated independently and therefore has to be considered separately in terms of energy.

[0018] It is already known from EP 3 387 354 A1 that, in order to provide a treatment system with a simple design and enabling energy-efficient workpiece treatment, the treatment system comprises a treatment chamber comprising a plurality of treatment chamber sections, each of which is assigned to one of a plurality of separate recirculation modules of the treatment system. The treatment system further comprises a heating system comprising a self-contained hot gas duct, wherein a plurality of recirculation modules are coupled to the hot gas duct, in particular for heating the gas guided through the treatment chamber sections.

[0019] The present invention is therefore based on the object of providing a treatment plant which enables sustainable operation.

[0020] This object is achieved according to the invention by a treatment plant having the features according to claim 1.

[0021] The treatment plant is in particular a drying plant for drying vehicle bodies.

[0022] The treatment system comprises the following: at least one treatment room, which comprises one or more treatment room sections, wherein the at least one treatment room and / or the one or more treatment room sections are each assigned to one of several separate recirculation modules, and wherein each recirculation module is arranged to carry a separate, circulating gas flow; and a heat transfer system for indirectly heating the gas flows, which comprises a heating device, wherein it can optionally be provided that a) at least one recirculation module has a heat exchanger by means of which the respective recirculation module is coupled to the heat transfer system; and / or b) several recirculation modules are integrated into one or more heating circuits, in particular heating gas circuits, which are coupled to the heat transfer system via a central heat exchanger.

[0023] The invention is based on the idea that, particularly when converting existing plants, it is possible to use other sustainable energy sources in addition to heating with electrical energy from renewable energy sources. Furthermore, conversion should also be possible in plants where no free space is available in the treatment plant area, especially in the drying plant area. The overall design of the plant should take sustainability and energy conservation into account, especially by minimizing power losses as much as possible.

[0024] Overall, it is advantageous to hydraulically decouple the treatment system into a primary and a secondary circuit via a hydraulic separator in order to ensure hydraulically independent operation of the heater circuit, i.e. the circuit of the heat transfer system, and the consumer circuit, i.e. the circuit of the recirculation modules, and to enable multiple feeding of the heat transfer medium from preferably different heat sources into the heater circuit.

[0025] It should be understood that one or more heating gas circuits can be coupled to the central heat exchanger, into each of which one or more recirculation modules can be integrated.

[0026] It is advantageous if the heat transfer system comprises: a closed heat transfer circuit which has at least one flow and at least one return and in which a heat transfer medium, in particular a liquid heat transfer medium, circulates.

[0027] It is conceivable that the heating circuit carries a heating gas or another heat transfer medium to which thermal energy has been transferred from the heat transfer system. In the case of a heating gas circuit, this is mixed directly into the gas streams circulating in the recirculation modules. Whereas in the case of another heat transfer medium, the heat energy is preferably only transferred into the gas streams of the recirculation modules, without the corresponding medium entering these gas streams.

[0028] The heating device is preferably installed centrally (e.g. at a location not subject to explosion hazard) and the heat is supplied to individual consumers, such as recirculation and / or fresh gas modules, via a branched pipe network using the heat transfer medium or the heating gas.

[0029] The heat transfer medium can be solid, liquid or gaseous.

[0030] A solid heat transfer medium may comprise spheres filled with a phase change material, whereas a gaseous heat transfer medium is preferably vaporous for safety reasons.

[0031] A liquid heat transfer medium is in particular a thermal oil, water or an ionic liquid, whereby, for example, the thermal oil is pressureless and is therefore easier to handle or pump than steam in the heat transfer system.

[0032] When using thermal oil as the heat transfer medium, the flow temperature is preferably 250 °C and the return temperature is preferably 230 °C.

[0033] The aim is to keep the thermal oil temperature as low as possible to prevent the formation of low-boiling components (the decomposition of hydrocarbon chains into smaller fragments). Such decomposition lowers the flash point and increases the risk of forming an ignitable mixture, as well as the tendency to cavitation, which can lead to increased wear on system components (e.g., pumps). Thus, by avoiding reaching the so-called film temperature of the thermal oil, the longevity of the oil is promoted or at least maintained.

[0034] The preferred temperature range, which is very low for thermal oil, allows for the well-known Arrhenius law, according to which the reaction rate increases exponentially with temperature, to be taken into account, thus keeping the risk to the safety and service life of plant components very low. At the same time, the thermal oil temperature is sufficient to bring the fresh gas supplied, such as fresh air from the treatment plant hall and from outside the plant building, to the required target temperature. This is usually 10 to 20 K higher than the circulating air temperature in the treatment room.

[0035] Another important aspect regarding thermal oil temperatures is worth mentioning. Due to the moderate temperature chosen, the oils are still within the range of mineral oils. Higher temperatures, however, would require a silicone-based or synthetic oil. However, these often have the disadvantage of containing substances that impair paint wetting properties and are therefore not permitted in a treatment facility such as a paint shop.

[0036] In addition, mineral oil is usually classified as water hazard class 1, which means no additional precautionary measures are required. Furthermore, pressureless operation is possible at a thermal oil temperature in the range of 230 °C to 250 °C. Only the pressure difference for forced circulation of the thermal oil in the distribution network, i.e., in the heat transfer circuit, must be created by a pumping device.

[0037] Compared to air, thermal oil also has a higher specific heat capacity and a higher density, which allows for significantly reduced pipe cross-sections in the heat transfer circuit compared to hot air ducts. Significantly smaller pipe cross-sections also mean significantly lower surface heat losses. This makes integration into existing systems easier.

[0038] It can further be provided that the heating device comprises at least one, preferably at least two different heat sources, wherein the heat source is configured as a) an electric heating register, and / or b) a gas-fired boiler, and / or c) a hydrogen-fired boiler, and / or d) a solar thermal auxiliary heating system, and / or e) a heating gas circuit. Carbonated hydrogen, natural gas, biogas, or methane, for example, can be used, i.e., in particular, combusted, in the gas-fired boiler.

[0039] The centralized installation of the heating system offers the advantage, particularly compared to the decentralized heating system mentioned above, that a heat source can be easily replaced or several different heat sources can be maintained in parallel. This option is particularly advantageous in times of the energy transition, as many operators currently cannot foresee which form of energy will be the energy of the future for their location. Furthermore, the centralized installation allows for easy, gradual expansion of the heating system.

[0040] In the case of the electric heating register, the following types of current are possible:

[0041] AC low voltage (400 kV)

[0042] The advantage is simple low-voltage technology on the heater side of the heating device, which results in low investment costs. However, higher cable power losses result compared to medium voltage, but these can be minimized by placing the corresponding heat source near a transformer center of gravity station, thus keeping cable lengths short. The transformation of the factory voltage or plant voltage to a low-voltage level also involves considerable investment costs.

[0043] AC medium voltage (1 to 35 kV)

[0044] The advantage is that smaller cable cross-sections and lower cable losses can be achieved compared to low voltage. Furthermore, savings can be achieved if the center-of-mass station cannot be located in the immediate vicinity of the heating device, so that the lower costs for the cabling and the transformer center-of-mass station more than compensate for the remaining costs (e.g., additional costs on the heater side). Furthermore, the transformation effort is reduced, or the transformer center-of-mass station can be eliminated, if the electric heating register can be operated directly at the medium-voltage level of the system network. However, compared to low voltage, more complex medium-voltage technology is required on the heater side, with the corresponding costs.

[0045] direct current

[0046] The potential of industrial DC power distribution is diverse. A DC distribution network or grid allows photovoltaic modules or decentralized energy storage systems, for example, to be easily integrated into the existing infrastructure. The direct current from photovoltaic modules is transmitted directly to built-in heating elements, for example, and converted into heat immediately and without loss. The resulting reduction in losses during AC-DC conversion, coupled with intelligent load management, can significantly reduce energy consumption and avoid peak loads. This, in turn, has a positive impact on device designs, installations, and lower electricity tariffs. The integration of photovoltaic modules and storage systems also increases supply security.

[0047] The gas-fired boiler is preferably used so that, in the event of an increased power requirement for heating the cold treatment plant compared to the required production or operating power, an unnecessary electrical power installation can be dispensed with by providing the difference in power compared to the electrically provided operating power with a gas-fired boiler.

[0048] At thermal oil flow temperatures of approximately 250 °C to 300 °C, concentrating solar thermal energy can be used as a supplementary solar thermal heating system for the system in sunny locations with a high proportion of direct solar radiation. Fresnel collectors installed on the roof of the treatment plant can be integrated into the thermal oil circuit either directly or via a heat exchanger. The former approach of direct integration would have the advantage of allowing the existing thermal oil circuit to be used for solar thermal energy.

[0049] Depending on the different designs of the treatment plant, the heating system can be operated using pure hydrogen heating or in a hybrid mode.

[0050] In hybrid operation, the installed electrical power is preferably reduced by hydrogen-assisted heating of the treatment plant, whereby the hydrogen demand in this case can be covered by a hydrogen tank.

[0051] Hydrogen heating offers the possibility of CC>2-neutral operation of the system.

[0052] A key challenge in the use of hydrogen is managing the risk of fire and explosion, which requires adequate protective measures. The risk of explosion is increased if hydrogen is released indoors. Furthermore, leaks are difficult to detect without special detectors. Furthermore, the diffusion of hydrogen can lead to material embrittlement if appropriate materials are used.

[0053] To best address these safety aspects, it is advantageous to locate the hydrogen-powered boiler or hydrogen-powered central heating unit outside the building in a well-ventilated location (e.g., outdoors). Any future safety regulations will then only affect the installation of the central heating unit and can be implemented with correspondingly less effort than in the case of an indoor installation.

[0054] If the hydrogen-powered boiler is to be or must be operated within the system or within a building, the pipes are welded, ensuring they are permanently technically leak-proof. As part of this process, a certain number of weld seams are regularly X-rayed, and all threaded and flange connections must be regularly inspected. It is recommended to implement hydrogen detection using one or more sensors and connect these to a gas warning system, allowing, for example, solenoid valves to shut down or block corresponding areas or sections in the event of an alarm.

[0055] Outdoor installation is made possible by the fact that the thermal energy generated by the hydrogen-powered boiler or the hydrogen-powered central heating unit is transferred to the hot gas circuit via the heat transfer circuit and the central heat exchanger, with the central heat exchanger preferably located within the building or hall of the treatment plant. For heat distribution within the treatment plant, the aforementioned hot gas circuit with a gaseous heat transfer medium is then suitable, with the heat supply to the recirculation modules being realized by admixing the hot gas. Accordingly, in the treatment plant design with a hot gas circuit, no heat exchangers are required in the recirculation modules; instead, so-called mixing valves are required to control and / or regulate the supplied hot gas volume flow.The return of the heating gas circuit to the central heat exchanger can also be designed as a simple return duct; preferably within the treatment room or the dryer tunnel ("triangular duct" in the rear wall / ceiling area), resulting in virtually no surface heat losses.

[0056] The central heat exchanger is preferably located close to the treatment plant. This reduces the risk of thermal oil contamination and, consequently, significantly reduces the fire load. In other words, locating the central heat exchanger near the treatment plant means fewer piping needs to be provided or shorter piping can be installed, reducing the total circulating volume of thermal oil and, in the event of an accident, also reducing the fire load.

[0057] It is further advantageous if a) the at least one heat source is interchangeable with another heat source; and / or b) at least two different heat sources can be operated in parallel and / or alternately.

[0058] Exchange should be understood as meaning that the operator of the treatment plant can easily replace the heat source previously used with a heat source of a different type in response to a changed supply situation.

[0059] Alternatively or additionally, the heating device can already have two or more different heat sources, so that depending on the

[0060] Depending on the supply situation or the available supply, the different heat sources can be operated in parallel or alternately, i.e., alternating with each other, in a hybrid heating system. It is advantageous if the heating device includes at least one expansion tank to compensate for a thermally induced volume change of the heat transfer medium.

[0061] The heat transfer medium, such as thermal oil, can expand freely via a non-sealable expansion line between the heat source and the expansion tank or vessel. A nitrogen blanket in the expansion tank ensures the necessary pressure equalization and seals off oxygen to prevent the oil from oxidizing.

[0062] In addition, the following safety measures should be mentioned, particularly with regard to the use of thermal oil or hydrogen as a heat transfer medium:

[0063] Monitoring of the volume flow, as defined in DIN 4754 parts 1 to 3;

[0064] Level switch in the expansion tank and / or deficiency protection on the boiler to prevent the system from being run "dry";

[0065] Monitoring of the flow temperature (maximum permissible temperature of the thermal oil);

[0066] Monitoring the maximum permissible flue gas temperature (oil or gas-fired boiler); and

[0067] Monitoring the minimum nitrogen pressure and / or monitoring the pressure of the heat transfer system using a minimum pressure limiter.

[0068] On the one hand, the aim is to achieve the lowest possible exhaust gas temperature, which is achieved, among other things, by a heat exchanger downstream of the exhaust gas purification device, which further cools the exhaust gas discharged from the treatment plant to utilize the calorific value effect.

[0069] Furthermore, the boilers preferably require a minimum flue gas temperature to avoid condensation.

[0070] In a further embodiment of the invention, it can be provided that the heating gas circuit, the heat of which can be transferred to the heat transfer circuit by means of at least one heat exchanger, comprises the following: at least one electrical heating device for heating the heating gas, at least one mixing device which is arranged downstream of the at least one electrical heating device, and at least one heat storage unit for storing and discharging heat, wherein the at least one heat storage unit is fluidly connected to the at least one mixing device.

[0071] In the heating gas circuit, the heating gas is generated by the at least one electric heating device, and its heat is optionally stored in the at least one heat storage unit or transferred to the heat transfer circuit by means of the at least one heat transfer device. The heat stored in the at least one heat storage unit can be released as needed and added to the heating gas. The heat is transferred into and out of the at least one heat storage unit via the at least one mixing device.

[0072] The intermediate buffering of heat in the at least one heat storage unit of the heating gas circuit is preferably carried out by storing the heat during weekends or during production breaks. Thus, the stored heat can be accessed in parallel with the heat provided or generated by the electric heating device when the treatment plant needs to be heated to operating temperature or when more heat is required during production peaks.

[0073] Preferably, several heat storage units form a heat storage unit, wherein it is advantageous if the heat storage units can be individually charged or discharged with heat.

[0074] The additional provision of heat from the at least one heat storage unit or from the heat storage advantageously enables faster heating rates compared to a system that only has an electric heater. A heat storage unit also allows for a reduction in the installed power of the electric heater and thus the required connected load of the treatment plant. Furthermore, the heating gas circuit with heat storage enables increased flexibility in electricity procurement, allowing for the exploitation of daily electricity price fluctuations.In a further embodiment of the invention, it is provided that the mixing device is designed such that heating gas heated in the electric heating device can be fed to the heat exchanger, or to the at least one heat storage unit for storing at least part of the heat contained in the heating gas, or to the heat exchanger with the addition of at least part of the heat stored in the at least one heat storage unit.

[0075] Thus, the mixing device advantageously has at least three switching positions via which the heating gas flow can preferably be directed.

[0076] Preferably, the heat generated from electrical energy in the at least one heating device is stored in the at least one heat storage unit at times of low electricity prices and, conversely, is released when electricity prices are high. It is therefore advantageous if the control variable in this context is the electricity price. Storing heat generated from electrical energy could also be used to respond to a power shortage or power outage.

[0077] The heat exchanger is preferably a gas-liquid heat exchanger, wherein to protect against the entrainment of liquid or heat transfer medium from the heat transfer circuit into the heating gas circuit, the heat exchanger preferably has a double wall and a liquid detection device between the inner and outer tubes.

[0078] In a further embodiment of the invention, it can be provided that the heat transfer system comprises a pump device with at least one pump for conveying the heat transfer medium through the heat transfer circuit and at least part of the heating device.

[0079] The at least one pump can be a circulation pump, for example. It is also conceivable for two or more pumps to be operated in parallel.

[0080] Furthermore, it can be provided that a hydraulic switch is provided between the at least one treatment room and the heat transfer system, by means of which the consumer circuit, which supplies the treatment room sections via the recirculation modules, is hydraulically decoupled from the heater circuit, ie the circuit of the heat transfer system.

[0081] In a further embodiment of the invention, it can be provided that the treatment plant comprises an exhaust gas purification device, in particular an electrically thermal exhaust gas purification device, for cleaning exhaust air, which can be fed from the treatment chamber to the exhaust gas purification device via an exhaust gas duct, wherein the exhaust gas purification device leads clean gas obtained by cleaning out of the treatment plant via a clean gas duct.

[0082] It should be understood that an electrically thermal exhaust gas purification device is preferably an exhaust gas purification device which also uses electrical energy from renewable energy sources.

[0083] The cleaning of the exhaust air from the treatment plant is preferably carried out separately from the heating.

[0084] In this context, catalytic afterburning is known as an exhaust gas purification process. This process is also known as catalytic oxidation and is preferably used to reduce hydrocarbon emissions. Its advantage over thermal afterburning lies in the lower reaction temperature. A reaction temperature of approximately 790 °C is required to ensure the exhaust air is sufficiently purified, although this temperature is essentially independent of whether an RTO or thermal afterburning is used. However, it must be noted that certain ingredients in the paint can act as catalyst poisons and clog the catalyst. The system's maintenance requirements and the risk of failure can therefore be high.

[0085] A thermal process is therefore preferable for cleaning the solvent-containing and odorous exhaust air. A thermal process, in particular, enables autothermal operation using the thermal energy released by the oxidation of solvents. Furthermore, a low clean gas temperature level results following post-combustion, and the clean gas enthalpy can be used to preheat the fresh gas supplied to the system. The low clean gas temperature is essentially due to the design or structure of the exhaust air cleaning device and is therefore not essentially a characteristic of the actual solvent combustion.

[0086] For the system according to the invention, an electrical and thus flameless operated, regenerative-thermal single-bed exhaust air purification system (RTO), which achieves high energy efficiency, is preferred for the exhaust air purification device.

[0087] The flow through the electrically heated bed is controlled and / or regulated by means of poppet valves, which are switched cyclically. As the fluid flows through the bed, it is preheated to the core; a chemical reaction takes place without the addition of combustion gas, but with the addition of electrical energy. The gas then cools down in the other half of the bed.

[0088] Once the system reaches operating temperature, often only the heat energy released by the oxidation of solvents is required to achieve self-sufficient and autothermal operation (from approx. 1 g solvent per m 3 Air); electrical heating or auxiliary heating is not required in this operating mode. The high efficiency of this device is evident from the fact that the outlet temperature of the clean gas is only 20 K above the inlet temperature of the exhaust air to be cleaned.

[0089] As already mentioned above, it is advisable to use the clean gas enthalpy with the help of a heat exchanger for fresh gas preheating if the exhaust air purification device is located near the treatment plant.

[0090] In this case, the already preheated fresh gas flow only needs to be brought to the final or target temperature of the inlet or outlet lock of the treatment room, for example with the help of another downstream heat exchanger such as a thermal oil-gas heat exchanger, which is coupled to the heat transfer medium circuit.

[0091] In a further embodiment of the invention, it can be provided that a fan for conveying the exhaust air is arranged in the exhaust duct. In a further embodiment of the invention, it can be provided that the one or more heating circuits each comprise at least one heating flow and at least one heating return, and wherein heating gas can be fed into and out of the at least one treatment chamber by means of the heating circuit.

[0092] Accordingly, the heating circuit either supplies heating gas directly into the treatment room or serves to heat the gas flow fed into the recirculation modules using a heat transfer medium, such as thermal oil.

[0093] In a further embodiment of the invention, it can be provided that at least one pump device, in particular a fan, is arranged in the heating flow and / or in the heating return, by means of which the heating gas or a heat transfer medium can be conveyed in the heating circuit.

[0094] In a further embodiment of the invention, it can be provided that the heating device is arranged spatially separate from the treatment room, preferably outdoors or in a well-ventilated room or part of the building.

[0095] This is particularly preferable if the heat energy generated by the heating device is primarily provided by a hydrogen-based boiler or a hydrogen-based heating unit,

[0096] In a further embodiment of the invention, it can be provided that the heat transfer system is designed as a compact device in which at least the heating device, the central heat exchanger and the heat transfer circuit are integrated.

[0097] Furthermore, the pump device can also be integrated into the compact device.

[0098] It is also advantageous if the heat source of the heating device is or includes an electric heating element, particularly an AC medium-voltage heating element. When using an AC medium voltage (1 to 35 kV), a liquid heat transfer medium must flow around the heating element to ensure heat dissipation at elevated temperatures and avoid temperature hotspots. The same applies analogously to other voltage ranges.

[0099] Even when using a heat transfer system designed as a compact unit, the heat transfer circuit and the heating gas circuit are coupled together via the central heat exchanger for heat transfer.

[0100] In a further embodiment of the invention, it can be provided that the treatment chamber has an inlet lock and / or an outlet lock, and wherein fresh gas can be supplied to the inlet lock and / or the outlet lock via a fresh gas supply.

[0101] By supplying fresh gas into the locks, a fresh gas silhouette can be created there, by means of which the atmosphere of the treatment room can be separated from the ambient atmosphere.

[0102] In a further embodiment of the invention, it can be provided that at least one fresh gas module is arranged in the fresh gas supply, by means of which the supplied fresh gas can be tempered, in particular heated.

[0103] Heating of the fresh gas is necessary to prevent condensation in the area of ​​the locks, which could otherwise impair the workpiece treatment in the treatment room.

[0104] In a further embodiment of the invention, it can be provided that a first fresh gas module is arranged in the fresh gas supply, by means of which at least part of the thermal energy of the clean gas can be transferred to the fresh gas, and that a second fresh gas module is arranged downstream of the first fresh gas module, by means of which the fresh gas can be heated to a desired temperature.

[0105] In a further embodiment of the invention, the second fresh gas module can comprise an electric heating coil and / or be coupled to the heat transfer medium circuit. Since treatment systems such as drying systems for vehicle bodies are typically equipped with an exhaust air purification device, it is advantageous to utilize the waste heat from the purification process by using the purified, hot clean gas enthalpy stream with the aid of a heat exchanger to preheat the fresh gas or fresh air.

[0106] In such a case, the fresh air flow is already preheated and only needs to be brought to the final or target temperature for the inlet and / or outlet lock in a second step or stage.

[0107] The use of waste heat or the thermal energy contained in the cleaned clean gas is particularly suitable if the drying plant and the exhaust air purification device are not located too far apart from each other.

[0108] If the drying system and the exhaust air purification system are located too far apart (for example, if the exhaust air purification system is located outside the building and / or on a different system level), preheating the fresh gas is not economically viable. To heat the fresh gas, or typically the fresh air, from the initial temperature, such as a hall temperature of 20 °C, to the target temperature, the only preheating or heating stage used is a fresh gas module with a heat exchanger coupled to the heat transfer medium circuit, or an electric heating coil contained in the fresh gas module to heat the fresh gas.

[0109] In a further embodiment of the invention, it can be provided that a fan for conveying the fresh gas is arranged in the fresh gas supply.

[0110] In a further embodiment of the invention, it can be provided that each recirculation module is assigned at least one control and / or regulating device, in particular a 3-way control valve, for controlling and / or regulating the temperature of the gas flows carried by the recirculation modules, wherein the control and / or regulating devices are preferably arranged in the flow of the heat transfer medium circuit and / or in the heating gas flow of the heating gas circuit. Via the control and / or regulating device, the recirculation modules and, if applicable, the affected fresh gas module are thus supplied with the required amount of thermal oil or - in the case of a central heat exchanger - the recirculation modules with the required amount of heating gas, wherein the controlled variable here is the recirculation temperature in the treatment room or the treatment room sections.

[0111] In a central heating system with a heat transfer circuit, the heat exchanger for each treatment room section or zone is designed according to the higher heating output required for the operating or heating-up mode. The control and / or regulating devices or control groups can then distribute the central, relatively constant electrical heating output of the heating device to the treatment room sections depending on the operating mode. It should be noted that the required heating output during operation and heating-up differ considerably.

[0112] Furthermore, it can be provided that each treatment chamber section is also assigned at least one control and / or regulating device by means of which the respective volume flow of the heating gas returned to the central heat exchanger can be controlled and / or regulated.

[0113] The object of the present invention is further achieved by a method for treating workpieces.

[0114] The process is used to treat workpieces, in particular to dry vehicle bodies.

[0115] The procedure includes the following steps:

[0116] Flowing through several treatment room sections of one or more treatment rooms of a treatment plant with several gas flows guided in separate circuits, wherein the gas flows are guided by separate recirculation modules, each of which is assigned to a treatment room section;

[0117] Heating the gas streams by means of a heat transfer medium circuit of a heat transfer system comprising a heating device, wherein it can optionally be provided that the thermal energy contained in the heat transfer medium of the heat transfer circuit is a) transferred to the gas streams via heat exchangers of the recirculating air modules; and / or b) transferred via a central heat exchanger to one or more heating circuits, in particular heating gas circuits, by means of which heating gas is added to the gas streams via the recirculating air modules.

[0118] In a further embodiment of the invention, it can be provided that the heating device has i) at least one replaceable heat source; and / or ii) at least two different heat sources for parallel and / or alternating heating of the heat transfer medium.

[0119] The method preferably has one or more of the features and / or advantages described in connection with the recirculation system. Furthermore, the recirculation system preferably has one or more of the features and / or advantages described in connection with the method.

[0120] Further preferred features and / or advantages of the invention are the subject of the following description and the drawings of exemplary embodiments.

[0121] The figures show:

[0122] Fig. 1 is a schematic representation of a first embodiment of a

[0123] treatment plant;

[0124] Fig. 2 is a schematic representation of a second embodiment of a

[0125] treatment plant;

[0126] Fig. 3 is a schematic representation of a third embodiment of a

[0127] treatment plant;

[0128] Fig. 4 is a schematic representation of a fourth embodiment of a

[0129] Treatment plant; Fig. 5 is a schematic representation of a fifth embodiment of a

[0130] treatment plant; and

[0131] Fig. 6 is a schematic representation of a sixth embodiment of a

[0132] Treatment plant.

[0133] Identical or functionally equivalent elements are provided with the same reference numerals in all figures.

[0134] A first embodiment of a treatment system designated as a whole by 100, shown in Fig. 1, is used to treat workpieces (not shown).

[0135] The treatment system 100 is in particular a drying system 102 for drying previously coated or painted vehicle bodies.

[0136] The treatment system 100 comprises a treatment room 104 with preferably several treatment room sections 105.

[0137] The treatment room sections 105 are preferably each assigned a recirculation module 106.

[0138] The treatment chamber 104 further comprises an inlet lock 108 and an outlet lock 110, which are each supplied with fresh gas 114, in particular fresh air, via a fresh gas supply 112 to form a fresh gas silhouette.

[0139] The fresh gas silhouettes in the inlet and outlet of the treatment room 104 serve to separate the atmosphere within the treatment room 104 from the surroundings.

[0140] A first fresh gas module 116 and, upstream thereof, a second fresh gas module 118 are arranged in the fresh gas supply 112, each having a heat exchanger 117. The first and second fresh gas modules 116, 118 can preheat the sucked-in or supplied fresh gas 114 in two stages, in particular to prevent condensation in the inlet and outlet locks 108, 110. The treatment system further comprises a heat transfer system 120, which has a closed heat transfer circuit 122, a heating device 124, and a pump device 126.

[0141] The heat transfer circuit 122, which has a flow line 128 and a return line 130, preferably circulates a liquid heat transfer medium such as a thermal oil, water, or an ionic liquid. A thermal oil is preferred as the heat transfer medium, ideally with a flow temperature of 250°C and a return temperature of 230°C.

[0142] The heating device 124 has at least one, preferably at least two different heat sources 132, wherein the heat source 132 is designed as a) an electric heating register 134, and / or b) a gas-powered boiler 136, and / or c) a hydrogen-powered boiler 138, and / or d) a solar thermal auxiliary heating 140.

[0143] Each heat source 132 of the heating device 124 is either interchangeable, or the heating device 124 maintains at least two different heat sources 132 for hybrid heating of the heat transfer medium. This ensures that the operator of the treatment plant 100 can react to changes in the energy market, for example, with regard to availability or price.

[0144] The pumping device 126, which is preferably arranged in the return line 130 of the heat transfer circuit 122, comprises two pumps 142, in particular two circulation pumps, by means of which the heat transfer medium is conveyed through the heat transfer circuit 122, in particular in a controlled forced circulation. The two pumps 142 are arranged in particular parallel to one another.

[0145] The heating device 124 further comprises an expansion tank (not shown) connected to the one or more heat sources 132 via a non-closable expansion line (not shown), allowing the heat transfer medium to expand. A nitrogen blanket in the expansion tank ensures the necessary pressure equalization and seals off any oxygen supply, thus preventing oxidation of the thermal oil when thermal oil is used as the heat transfer medium.

[0146] The heating device 124 also preferably comprises a control and / or regulating group (not shown) by means of which the circulation in the heat transfer medium circuit 122 can be controlled and / or regulated.

[0147] The heat transfer medium heated in the heating device 124 is fed via the flow 128 of the heat transfer circuit 122 to the recirculation modules 106 and the second fresh gas module 118.

[0148] Each recirculation module 106 has a heat exchanger 144, in particular an oil-air heat exchanger, and a circulating fan 146, in particular a fan, wherein by means of the circulating fan 146 a gas stream is guided in a circuit through the associated treatment chamber section 105.

[0149] The heat exchangers 128 of the recirculation modules 106 transfer at least part of the thermal energy of the heat transfer medium supplied via the flow line 128 to the gas flow of the respective treatment chamber section 105.

[0150] In a comparable manner, at least part of the thermal energy is transferred from the heat transfer medium in the flow 128 to the fresh gas 114 in the second fresh gas module 118 with the aid of the corresponding heat exchanger 117.

[0151] The heat transfer medium cooled by heat transfer is returned from the recirculation modules 106 or the second fresh gas module 118 via the return line 130 of the heat transfer circuit 122 to the heating device 124 to be reheated there.

[0152] Each recirculation module 106 and the second fresh gas module 118 are each assigned a control and / or regulating device 148, in particular a 3-way control valve, which is arranged upstream of the respective recirculation module 106 or the second fresh gas module 118 in the flow line 128 of the heat transfer medium circuit 122. The control devices 148 can be used to control and / or regulate the temperature of the gas stream circulated by the recirculation modules 106 in the associated treatment chamber section 105 or the temperature of the fresh gas 114 conveyed by the second fresh gas module 118.

[0153] The treatment plant 100 further comprises an exhaust air purification device 150, in particular an electrically thermal exhaust air purification device. An exhaust air purification device configured as a catalytic afterburner is particularly preferred.

[0154] The exhaust air purification device 150 cleans at least part of the exhaust air of the treatment room 104, which is supplied to it via an exhaust air duct 152, wherein the exhaust air duct 152 is preferably discharged at one of the central treatment room sections 105.

[0155] A clean gas 154 is discharged from the exhaust air purification device 150 as cleaned exhaust air via a clean gas duct 155. The clean gas duct passes through the heat exchanger 117 of the first fresh gas module 116 and transfers at least a portion of the thermal energy contained in the clean gas in the heat exchanger 117 of the first fresh gas module 116 to the fresh gas 114 supplied to the treatment system 100.

[0156] The cooled clean gas 154 is finally led out of the treatment plant 100 via the roof.

[0157] The embodiments described below preferably have one or more of the features and / or advantages described in connection with the first embodiment and vice versa.

[0158] In Fig. 2, a second embodiment of the treatment plant 100 according to the invention is shown schematically.

[0159] In the second embodiment, the heating device 124 is preferably hydrogen-powered, i.e., the heat transfer medium, which is preferably liquid, is primarily heated by the hydrogen-powered boiler 138. For safety reasons, it is recommended that a hydrogen-powered heating device 124 be arranged outside a building boundary 156 of the treatment plant 100, e.g., outdoors or in a separate and well-ventilated part of the building of the treatment plant 100.

[0160] The spatial separation of the heat transfer system 120 and the treatment chamber 104 requires that the heat transfer from the heat transfer medium into the treatment chamber 104 or into the treatment chamber sections 105 must be designed differently in order not to lose part of the thermal energy temporarily stored in the heat transfer medium along the flow line 128 or the supply line.

[0161] The heat transfer medium circuit 122 is therefore coupled to a heating circuit 160, which is designed as a hot gas circuit, via a central heat exchanger 158. The heating circuit 160 has a heating flow 162 extending from the central heat exchanger 158 and a heating return 164 leading back to the central heat exchanger 158.

[0162] Thermal energy from the heat transfer medium conducted in the heat transfer circuit 122 is transferred to the heating gas circulating in the heating circuit 160 in the central heat exchanger 158 and is led to the recirculation modules 106 via the heating flow 162 of the heating circuit 160.

[0163] A fan 166 is arranged in the heating flow 162 of the heating circuit 160, in particular directly downstream of the central heat exchanger 158.

[0164] The recirculation modules 106 in the second embodiment of the treatment system 100 do not have their own heat exchangers, since they are supplied with the already heated heating gas, which is then mixed with the gas stream circulating in the respective treatment chamber section 105. For mixing, the recirculation modules 106 can each have at least one mixing flap (not shown).

[0165] In the case of the second embodiment in Fig. 2, each recirculation module 106 is also assigned a control and / or regulating device 148 in the heating flow 162, by means of which the temperature of the gas flow circulated by the corresponding recirculation module 106 can be controlled and / or regulated. The heating gas is returned to the central heat exchanger 158 via the heating return 164, which is preferably designed as a return duct within the treatment chamber 104 and particularly preferably as a triangular duct in the ceiling area and extends along the entire treatment chamber 104. There, thermal energy is again transferred from the heat transfer medium circuit 122 to the heating gas.

[0166] Each treatment chamber section 105 can be assigned a control and / or regulating device 167, by means of which the respective volume flow of the heating gas returned to the heating return line 164 can be controlled and / or regulated.

[0167] In comparison to the first embodiment in Fig. 1, alternatively or additionally a fan 168 is arranged in the exhaust air duct and a fan 170 is arranged at the inlet of the fresh gas supply 112, which convey the respective guided gas flow in the direction of the exhaust air purification device 150 or the first fresh gas module 116.

[0168] The second stage of fresh gas heating, i.e., the second fresh gas module 118, is coupled to the heat transfer medium circuit 122, depending on the type of system. In this case, the second fresh gas module 118 has a heat exchanger 117. Alternatively, the second fresh gas module 118 is not coupled to the heat transfer medium circuit 122 and, instead of the heat exchanger 117, comprises an electric heating register, by means of which the fresh gas is also heated to the target temperature for the inlet and / or outlet lock 108, 110.

[0169] In Fig. 3, a third embodiment of the treatment plant 100 according to the invention is shown schematically.

[0170] In direct comparison with the second embodiment, the heat transfer system 120, which is preferably arranged or installed within the building boundaries of the treatment room 104, is designed as a compact device 172.

[0171] The compact device 172 comprises the central heat exchanger 158, which is coupled to the heating circuit 160, the heat transfer circuit 122, the pump device 126, which comprises or is only a pump 142 due to the shortened flow and return lines 128, 130, and the heating device 124, which is or comprises an electric heating register 134, in particular an AC medium-voltage heating register 174.

[0172] Such a compact device 172 can be arranged in the treatment plant 100 in such a way that short cable routes can be realized for the heating circuit 160. Furthermore, if the AC medium-voltage heating register 174 can be operated directly at the medium-voltage level of the plant network or system network, the need for a transformer center station is eliminated.

[0173] The fourth embodiment of the treatment system 100 according to the invention shown in Fig. 4 differs from the first embodiment in Fig. 1 in that the treatment system 100 comprises, instead of a treatment chamber 104 with a plurality of treatment chamber sections 105, a plurality of separate treatment chambers 104, each of which has an inlet lock 108, an outlet lock 110 and only one treatment chamber section 105 for the treatment of workpieces.

[0174] Each treatment room 104 is assigned a recirculation module 106.

[0175] A fresh air silhouette can be formed in the inlet and / or outlet locks 108, 110 to atmospherically separate the respective treatment chamber sections 105 from the surroundings. However, it is also conceivable that the inlet and / or outlet locks 108, 110 alternatively or additionally comprise or are designed with a closure element such as a gate.

[0176] The fifth embodiment of the treatment system 100 according to the invention, shown in Fig. 5, differs from the first embodiment in Fig. 1 in that, with respect to the conveying direction, which preferably runs from left to right in Figs. 1 to 5, a pre-dryer chamber 176 is arranged upstream of the treatment chamber 104, in which the workpieces undergo a preliminary treatment, such as pre-drying. This makes it possible, for example, to influence, in particular reduce, the temperature level in the treatment chamber sections 105 of the treatment chamber 104. In Fig. 6, the heat source 132 of the heating device 124 is a heating gas circuit 178, wherein the heat of the heating gas conducted in the heating gas circuit 178 can be transferred to the heat transfer medium circuit 122 by means of a heat exchanger 180.

[0177] The heating gas circuit 178 preferably comprises an electric heating device 182, a mixing device 184 and at least one, preferably three heat storage units 186, which together form a heat storage unit.

[0178] The heating gas circuit 178 further preferably comprises a first and a second blower compressor 190, 192 driven by a motor 188, which convey the heating gas flow in the heating gas circuit 178.

[0179] Furthermore, the heating gas circuit preferably comprises a silencer unit 194, which reduces the noise emission when fresh air 196 is supplied to the heating gas circuit 178.

[0180] In addition, the heating gas circuit 178 preferably comprises nine controlled and / or regulated valves 198 for controlling and / or regulating the heating gas flow in the heating gas circuit 178.

[0181] During normal operation, fresh air 196 is supplied to the heating gas circuit 178, which initially passes through the silencer unit 194 to reduce noise emissions.

[0182] The volume flow of the fresh air supply is controlled and / or regulated via a valve 198, which is arranged downstream of the silencer 194 and is preferably piston-controlled and / or regulated.

[0183] The supplied fresh air is conveyed by means of the first blower compressor 190 in the direction of the electric heating device 182, in which the supplied fresh air 196 is heated.

[0184] Downstream of the electric heating device 182 is the mixing device 184, which, during normal operation, directs the gas heated in the electric heating device 182, i.e., the heating gas, according to its switching position. The mixing device 184 preferably has at least three switching positions.

[0185] In the first switching state, the heating gas supplied by the electric heating device 182 is directed exclusively in the direction of the heat exchanger 180 arranged downstream of the mixing device 184.

[0186] In the second switching state, the heating gas is directed exclusively towards the heat storage units 186 for storing the heat.

[0187] And in the third switching position, the heating gas coming from the electric heating device 182 is directed towards the heat exchanger 180 with the addition of the heat stored in the heat storage units 186.

[0188] In normal operation, the mixing device 184 in its first switching position directs the heating gas through a downstream valve 198 in the direction of the heat exchanger 180, wherein this valve 198 regulates and / or controls the volume flow of the heating gas.

[0189] Thus, in so-called normal operation, no heating gas is fed into the heat storage units 186 for storage.

[0190] The heat exchanger 180 is assigned two valves 198, which direct the heating gas through the heat exchanger 180 or bypass it.

[0191] Furthermore, a pump 200 is assigned to the heat exchanger 180, which circulates the heating gas coming via the mixing device 184 through the heat exchanger 180.

[0192] The gas flow downstream of the heat exchanger 180 is then conveyed by the second blower compressor 192 towards the electric heating device 184 for reheating.

[0193] Downstream of the second blower compressor 192, two controlled and / or regulated valves 198 are preferably arranged, which control and / or regulate the volume flow toward the electric heating device 182. When heat is stored in the heat storage units 186, the mixing device 184, in its second switching position, directs the generated heating gas into them. Fig. 6 shows three parallel heat storage units 186, into which heat is stored in parallel.

[0194] However, it is also conceivable that heat is supplied to only one heat storage unit 186 or only to a part of the heat storage units 186, for which purpose additional valves can be provided between the mixing device 184 and the heat storage units 186.

[0195] During the storage process, the valves 198 assigned to the respective heat storage unit 186, which are arranged downstream of the respective heat storage units 186, are at least partially opened in order to preferably allow the residual gas contained in the heat storage units 186, which is displaced by the supplied heating gas and preferably has a lower temperature than the supplied heating gas, to flow into the heating gas circuit 178.

[0196] At the end of the heat storage, the valves 198 associated with the heat storage units 186 are closed and the mixing device 184 is preferably switched to its first switching position.

[0197] In full-load operation, in which it is necessary, for example, to bring the heat exchanger 180 to the required operating temperature very quickly, the mixing device 184 is switched to its third switching position in order to mix the heat stored in the heat storage units 186, preferably temporarily, with the heating gas heated in the electric heating device 182.

[0198] Preferably, as soon as the required operating temperature has been reached, the mixing device 184 switches back to its first switching position, whereby no further heat is stored from the heat storage units 186.

[0199] During any downtime or break times or at times of low electricity prices, heat can then preferably be stored again in the heat storage units 186, for example, to keep them available for full-load operation.

[0200] Treatment plant Drying plant Treatment room Treatment room section Recirculation module

[0201] Inlet lock

[0202] Outlet lock Fresh gas supply Fresh gas First fresh gas module Heat exchanger Second fresh gas module Heat transfer system Heat transfer circuit Heating device Pumping device Flow

[0203] Return

[0204] Heat source electric heating register gas-fired boiler hydrogen-fired boiler solar thermal auxiliary heating pumps

[0205] Heat exchanger circulation fan

[0206] Control and / or regulation device Exhaust air purification device Exhaust air duct

[0207] Clean gas

[0208] Clean gas routing building boundary central heat exchanger

[0209] Heating circuit

[0210] Heating flow

[0211] Heating return

[0212] fan

[0213] Control and / or regulating device

[0214] fan

[0215] Ventilator172 compact unit

[0216] AC medium-voltage heating register

[0217] Pre-dryer room

[0218] Heating circuit

[0219] Heat exchanger electric heating device

[0220] Mixing device

[0221] Heat storage unit

[0222] Motor for blower compressor first blower compressor second blower compressor

[0223] silencer unit

[0224] Fresh air controlled and / or regulated valve pump

Claims

A treatment system (100) for treating workpieces, in particular a drying system (102) for drying vehicle bodies, comprising: at least one treatment chamber (104) which comprises one or more treatment chamber sections (105), wherein the at least one treatment chamber (104) and / or the one or more treatment chamber sections (105) are each assigned to one of several separate recirculation modules (106), and wherein each recirculation module (106) is arranged to carry a separate, circulating gas flow; and a heat transfer system (120) for indirectly heating the gas flows, which comprises a heating device (124), wherein a) at least one recirculation module (106) has a heat exchanger (144) by means of which the respective recirculation module (106) is coupled to the heat transfer system (120);and / or b) a plurality of recirculation modules (106) are integrated into one or more heating circuits (160), in particular heating gas circuits, which are coupled to the heat transfer system (120) via a central heat exchanger (158). Treatment system (100) according to claim 1, characterized in that the heat transfer system (120) comprises: a closed heat transfer circuit (122) which has at least one flow line (128) and at least one return line (130) and in which a liquid heat transfer medium, in particular thermal oil, water, or ionic liquid, circulates. Treatment plant (100) according to claim 1 or 2, characterized in that the heating device (124) comprises at least one, preferably at least two different heat sources (132), wherein the heat source (132) is a) an electric heating register (134), and / or b) a gas-operated boiler (136), and / or c) a hydrogen-operated boiler (138), and / or; d) a solar thermal auxiliary heating system (140), and / or e) a heating gas circuit (178) is provided. Treatment system (100) according to claim 3, characterized in that a) the at least one heat source (132) is interchangeable with another heat source (132); and / or b) at least two different heat sources (132) can be operated in parallel and / or alternately.Treatment system (100) according to claim 3 or 4, characterized in that the heating gas circuit (178), the heat of which can be transferred to the heat transfer medium circuit (122) by means of at least one heat exchanger (180), comprises the following: at least one electrical heating device (182) for heating the heating gas, at least one mixing device (184) arranged downstream of the at least one electrical heating device (182), and at least one heat storage unit (186) for storing and discharging heat, wherein the at least one heat storage unit (186) is fluidly connected to the at least one mixing device (184). Treatment system (100) according to one of claims 1 to 5, characterized in that the heat transfer medium system (120) comprises a pump device (126) with at least one pump (142) for conveying the heat transfer medium through the heat transfer medium circuit (122) and at least a portion of the heating device (124).Treatment plant (100) according to one of claims 1 to 6, characterized in that the treatment plant (100) comprises an exhaust gas purification device (150), in particular an electrically thermal exhaust gas purification device, for cleaning exhaust air, which can be fed from the treatment space (104) via an exhaust gas duct (152) to the exhaust gas purification device (150), wherein the. An exhaust gas purification device (150) guides clean gas (154) obtained by cleaning out of the treatment plant (100) via a clean gas guide (155). Treatment plant (100) according to one of claims 1 to 7, characterized in that the one or more heating circuits (160) each comprise at least one heating flow (162) and at least one heating return (164), and wherein heating gas can be guided into the at least one treatment chamber (104) and out of the at least one treatment chamber (104) by means of the one or more heating circuits (160). Treatment plant (100) according to claim 8, characterized in that at least one pump device, in particular a fan (166), is arranged in the heating flow (162) and / or in the heating return (164), by means of which pump device the heating gas or a heat transfer medium can be conveyed in the heating circuit (160).Treatment system (100) according to one of claims 1 to 9, characterized in that the heating device (124) is arranged spatially separate from the treatment chamber (104), preferably outdoors or in a well-ventilated room or part of a building. Treatment system (100) according to one of claims 6 to 10, characterized in that the heat transfer system (120) is designed as a compact device (172) into which at least the heating device (124), the central heat exchanger (158), and the heat transfer circuit (122) are integrated. Treatment system (100) according to claim 11, characterized in that the heat source (132) of the heating device (124) is or comprises an electrical heating register (134), in particular an AC medium-voltage heating register (170).Treatment plant (100) according to one of claims 1 to 12, characterized in that the treatment chamber (104) has an inlet lock (108) and / or an outlet lock (110), and wherein the inlet lock. (108) and / or the outlet lock (110) via a fresh gas supply (112). Treatment plant (100) according to claim 13, characterized in that at least one fresh gas module (116, 118) is arranged in the fresh gas supply (112), by means of which the supplied fresh gas (114) can be temperature-controlled, in particular heated. Treatment plant (100) according to claim 14, characterized in that a first fresh gas module (116) is arranged in the fresh gas supply (112), by means of which at least part of the thermal energy of the clean gas (154) can be transferred to the fresh gas (114), and in that a second fresh gas module (118) is arranged downstream of the first fresh gas module (116), by means of which the fresh gas can be heated to a desired temperature. Treatment plant (100) according to claim 15, characterized in that the second fresh gas module (118) comprises an electric heating register and / or is coupled to the heat transfer medium circuit (122).Treatment system (100) according to claims 2 to 16, characterized in that each recirculation module (106) is assigned at least one control and / or regulating device (148), in particular a 3-way control valve, for controlling and / or regulating the temperature of the gas streams guided by the recirculation modules (106), wherein the control and / or regulating devices (148) are preferably arranged in the supply line (128) of the heat transfer circuit (122) and / or in the heating supply line (162) of the heating circuit (160). A method for treating workpieces, in particular for drying vehicle bodies, wherein the method comprises the following steps: Flowing through a plurality of treatment chamber sections (105) of one or more treatment chambers (104) of a treatment plant (100) with a plurality of gas flows guided in separate circuits, wherein the gas flows are guided by separate recirculation modules (106), each of which is assigned to a treatment chamber section (105); Heating the gas streams by means of a heat transfer medium circuit (122) of a heat transfer system (120) comprising a heating device (124), wherein the thermal energy contained in the heat transfer medium of the heat transfer medium circuit (122) is a) transferred to the gas streams via heat exchangers (144) of the recirculating air modules (106); and / or b) transferred via a central heat exchanger (158) to one or more heating circuits (160), in particular heating gas circuits, by means of which heating gas is added to the gas streams via the recirculating air modules (106). The method according to claim 18, characterized in that the heating device (124) has i) at least one interchangeable heat source; and / or ii) at least two different heat sources for parallel and / or alternating heating of the heat transfer medium.

Images