Conversion kit for a treatment system and method for converting a treatment system

Abstract

The invention relates to a conversion kit (202) suitable for converting a treatment system, more particularly an existing treatment system, for treating workpieces, in particular for drying vehicle bodies, the conversion kit (202) comprising the following: - one or more additional heating devices (206, 208, 210) suitable for heating a clean gas conducted in a clean-gas guide (126) or fresh air conducted in a fresh-air guide (122); and a) a regenerative thermal oxidation device (204) as a replacement for a thermal post-combustion device (142), in particular fossil-fueled thermal post-combustion device; or b) a regenerative thermal oxidation device (204) as a replacement for a fresh-air heat exchanger (144) and a converted thermal post-combustion device (142), in particular fossil-heated thermal post-combustion device, for use as a fresh-air heat exchanger (150); or c) a regenerative thermal oxidation device (204) as a replacement for a thermal post-combustion device (142), in particular fossil-fueled thermal post-combustion device, and electrically heated air circulation modules (214) as a replacement for air circulation modules (110) with heat exchanger or converted air circulation modules (214) with electrical heating registers instead of heat exchangers.

Description

[0001] Conversion kit for a treatment plant and method for converting a treatment plant

[0002] The present invention relates to a conversion kit for converting a treatment plant, in particular an existing treatment plant, for the treatment of workpieces, in particular drying vehicle bodies, and a method for converting a treatment plant.

[0003] In the course of combating global warming, more and more automobile manufacturers are considering converting existing treatment or drying systems in the bodywork sector from fossil fuel heating (gas, petroleum, etc.) to heating using electrical energy from renewable energy sources.

[0004] The state of the art in heating such drying systems, or dryers for short, is the combination of exhaust air cleaning and heat generation. The residual heat from the cleaned dryer exhaust air, also known as clean gas, is used in downstream heat recovery systems to heat the recirculating air in the recirculating air units or modules of the individual dryer zones or sections, as well as to heat the fresh air in the fresh air units or heat exchangers, before the exhaust air is subsequently discharged into the atmosphere (via the roof).

[0005] For the technical ventilation of drying systems in the body shop, a constant exchange of the dryer atmosphere containing solvents (exhaust air) with a solvent-free fresh air stream is provided. For this purpose, an exhaust air volume flow is extracted from one or more locations in the treatment room or drying tunnel using an exhaust fan and fed into an exhaust air purification device, usually a recuperative thermal afterburner (TAR).

[0006] The cleaned exhaust air volume flow, i.e. the clean gas, is available for dryer heating at a temperature of approximately 450 °C when a TAR is used.

[0007] The individual dryer sections are heated via recirculation modules with their own heat exchangers, while the clean gas stream cools along the clean gas duct that connects the recirculation modules. Finally, the clean gas stream flows through a fresh air heat exchanger and exits the drying system at a temperature of, for example, 130 °C above the roof.

[0008] Alternatively or additionally, recirculation modules are conceivable, each of which comprises a separate combustion device or is coupled to such a device, whereby the recirculation modules are configured in such a way that they can heat the respective local recirculation air flow, which is guided in a local recirculation duct through the respective associated treatment room section.

[0009] The minimum exhaust air volume flow is determined by the standard based on the lower explosion limit, but in practice is correspondingly higher so that the dryer energy requirement can be covered by the clean gas enthalpy flow.

[0010] When converting drying plants from fossil to electric heating, it is obvious that the possibilities of direct electric heating should be exploited.

[0011] Direct heating converts electrical energy into heat energy. The current flows into a heating coil or heating wire. This creates a resistance, which in turn generates heat. The heat is transferred directly to the air stream (e.g., recirculating or fresh air) via heat conductors such as heating fins.

[0012] Fossil heating is accompanied by an exhaust gas stream that contains pollutants such as nitrogen oxides, which must not enter the dryer atmosphere because they have a negative effect on the paint quality.

[0013] For this reason, fossil-fired drying systems are equipped with indirect heating. With the help of heat exchangers, in particular those connected in series and preferably integrated into the recirculation modules, the thermal energy of the flue gas, i.e. the gaseous combustion product from the technical combustion of fuels, or the clean gas from the central exhaust air cleaning or treatment device is transferred to the dryer atmosphere, which includes both recirculated air and fresh air, without any material mixing of the two media, i.e. no mixing of flue gas or clean gas with recirculated air and fresh air. If such fossil-fired heating systems are to be converted to electric heating, it is state of the art and also known from new systems to dismantle the existing system components for indirect heat transfer and replace them with electric heating registers.

[0014] These electric heating registers then find their place, for example, as decentralized heat sources in the recirculation units and / or fresh air units.

[0015] The dryer exhaust air is then cleaned separately from the dryer heater. Thermal processes are generally used to clean the solvent-containing and odorous exhaust air.

[0016] These processes can be heated to operating temperature using fossil fuels or electrical energy. Once the system reaches operating temperature, often – depending on the solvent load – only the heat energy released by solvent oxidation is required to achieve self-sufficient, autothermal operation.

[0017] However, it is known from practice that when converting from fossil to electric heating of drying plants, concepts are used that are used when setting up new plants.

[0018] These concepts bring with them the following disadvantages and problems in the case of existing systems.

[0019] The installation of a decentralized electrical heating system, in which the individual recirculation and fresh air units are equipped with their own electric heating registers, requires a significant amount of mechanical modification to the individual units, as, among other things, the clean gas heat exchanger must be replaced with an electric heating register. In addition, a significant amount of electrical installation work is required on the individual recirculation units, including the positioning of the control cabinet with the connection to the heating register, as well as the positioning and connection of the main station with the low-voltage system. Furthermore, the placement or positioning of one or more main stations for supplying power to the individual heating registers within the framework of a decentralized electrical heating system largely determines the cable lengths to the individual heating registers and the associated costs.

[0020] In addition, free installation space is rare, especially for existing systems.

[0021] Furthermore, the conversion also entails dismantling the existing heating system, i.e., dismantling the clean gas line along the entire length of the dryer, dismantling the clean gas ducts and dampers in the area of ​​the recirculation / fresh air units, and possibly dismantling the exhaust air duct to the TAR. The latter depends on where the new exhaust air cleaning system is to be or can be located.

[0022] Another factor to be considered is the high time and financial expenditure that a conversion entails, because such a conversion or retrofitting can hardly be realized during a shutdown phase and also requires sufficient available manpower.

[0023] The present invention is based on the object of providing a conversion kit which enables an efficient conversion of treatment plants to electrical heating.

[0024] This object is achieved according to the invention by a conversion kit having the features according to claim 1.

[0025] The conversion kit according to the invention serves or is suitable for converting a treatment plant, in particular an existing treatment plant, for the treatment of workpieces, in particular drying of vehicle bodies.

[0026] The conversion kit according to the invention comprises the following: one or more additional heating devices which are suitable for heating a clean gas guided in a clean gas duct and / or fresh air guided in a fresh air duct; and a) a regenerative thermal oxidizer as a replacement for a thermal afterburner, in particular a fossil-fuel-heated one (hereinafter also referred to as case a)); or b) a regenerative thermal oxidizer as a replacement for a fresh air heat exchanger and a converted, in particular a fossil-fuel-heated, thermal afterburner for use as a fresh air heat exchanger (hereinafter also referred to as case b));or c) a regenerative thermal oxidiser as a replacement for a thermal afterburner, in particular one heated by fossil fuels, and electrically heated recirculation modules as a replacement for recirculation modules with heat exchangers or converted recirculation modules with electric heating registers instead of heat exchangers (hereinafter also referred to as case c)).

[0027] The treatment plant to be converted, which is preferably or includes an existing treatment plant with a convertible basic structure, has a conveying direction and comprises the following: a treatment chamber which comprises a plurality of treatment chamber sections, each of which is assigned to a separate recirculation module, each of which comprises a heat exchanger; an exhaust air duct which removes exhaust air from the treatment chamber; the thermal afterburning device, in particular one heated by fossil fuels, for processing, in particular for cleaning, the exhaust air, which is provided for conversion or replacement; a clean gas duct which guides cleaned exhaust air, in particular clean gas, wherein the clean gas duct preferably runs at least approximately parallel to the conveying direction; and a fresh air supply which supplies fresh air to the treatment chamber.

[0028] Furthermore, the treatment chamber preferably comprises a pre-treatment chamber which is arranged upstream of the treatment chamber with respect to the conveying direction, and / or a post-treatment chamber which is arranged downstream of the treatment chamber with respect to the conveying direction.

[0029] The invention is based on the fundamental idea of ​​keeping the cost of converting a treatment plant as low as possible and maximizing the number of components of the existing plant that can be reused or reused. Accordingly, the conversion to electric heating is not aimed at direct heating, but rather at making the existing indirect heating system compatible with electric heating.

[0030] Consequently, the previously fossil-fired TAR is replaced by an electric and thus flameless regenerative thermal oxidizer (F-RTO), which preferably includes a single-bed exhaust air purification system, and the dryer exhaust air is used as a heat transfer medium for the electrical heating.

[0031] Furthermore, the clean gas infrastructure can be reused, particularly for central and indirect electrical dryer heating.

[0032] Various positions within the treatment plant are possible for the F-RTO. One option is to position the F-RTO at the beginning of the heat transfer line, i.e., directly after the exhaust air is discharged from the dryer, where the temperature increase from the exhaust air purification is used to heat the exhaust air by approximately 20 K. The other option is to position the F-RTO at the end of the heat transfer line, i.e., after the fresh air unit or fresh air heat exchanger, where the temperature increase is then utilized with the help of other heat recovery measures.

[0033] It is particularly advantageous if the F-RTO contains a single horizontal, electrically heated bed and the flow direction can be cyclically switched via poppet valves. As the flow passes through the bed, the material is preheated down to the core, resulting in chemical conversion without the need for combustion gas.

[0034] The gas then cools down on the other half of the bed.

[0035] It can be advantageous to operate the F-RTO autothermally once the solvent concentration has exceeded a certain limit. In the case of an autothermal reaction, for example, at a solvent concentration of 1 g / m 3approximately 20 K in temperature, with the temperature gain increasing with rising solvent concentration. The F-RTO can preferably have a catalytic effect. Preferably, all electrically operated heating components (such as the electrically operated additional heating devices) of the converted treatment plant can be supplied with a medium voltage of, for example, at least approximately 3 kV and / or at most approximately 8 kV, in particular 4,160 V to 6,600 V, instead of the usual 400 V. Although this may require special heating elements with corresponding additional costs, it offers great savings potential, preferably in the periphery, ie with regard to connections, cables, etc. In addition, a significantly lower voltage transformation factor from the supply network is necessary, which, among other things, reduces the size of the transformer station in favor of lower investment costs and saves space.The connection to an electrically operated heating component with such a medium voltage also results in significantly smaller cable diameters.

[0036] In one embodiment of the invention, it can be provided that the treatment plant to be converted further comprises a fresh air heat exchanger which is designed to transfer thermal energy contained in the clean gas to the fresh air supplied to the treatment plant.

[0037] In a further embodiment of the invention, it can be provided that the one or more additional heating devices are purely electrically operated, hydrogen-operated or thermal oil-operated additional heating devices.

[0038] However, the corresponding upper temperature limit must be observed for thermal oil-operated auxiliary heating devices.

[0039] In a further embodiment of the invention, it can be provided that the regenerative thermal oxidation device is a purely electrically operated, flameless, regenerative thermal oxidation device.

[0040] In a further embodiment of the invention, it can be provided that the one or more purely electrically operated auxiliary heating devices and / or the purely electrically operated, flameless, regenerative thermal oxidizer can be connected to a central electrical connection point, in particular a center station. A central electrical connection point not only saves installation space but also reduces costs.

[0041] In a further embodiment of the invention, it can be provided that the regenerative thermal oxidation device comprises a fan for conveying an air flow.

[0042] In a further embodiment of the invention, it can be provided that in case b) of replacing the fresh air heat exchanger with a regenerative thermal oxidation device, the thermal afterburning device of the treatment plant, which is heated in particular by fossil fuels, can be used as a fresh air heat exchanger, in particular after the conversion.

[0043] The old TAR serves as the new fresh air heat exchanger in its previous location. Following the conversion, the TAR of the treatment plant has ceased to serve as a treatment device, and its effective internal heat exchanger is used to heat fresh air at the end of the exhaust air line.

[0044] In a further embodiment of the invention, it can be provided that in case c) the clean gas can be guided exclusively to the fresh air heat exchanger by means of the clean gas guide, ie in particular that the clean gas is not guided through the recirculation modules.

[0045] In a further embodiment of the invention, it can be provided that in the case of a) and c) the clean gas guide can be flowed through in the conveying direction.

[0046] Existing treatment plants are also known in which the TAR is located near the outlet of the treatment chamber, while the fresh air heat exchanger is located near the inlet. With such an arrangement, a modification of the plant according to cases a) and c) would still result in the clean gas flow continuing to be directed counter to the conveying direction.

[0047] In contrast, in a further embodiment of the invention, it can be provided that, in the case of b), the clean gas duct can be flowed through counter to the conveying direction. In a further embodiment of the invention, it can be provided that the regenerative thermal oxidation device is arranged at one end of the clean gas duct, relative to the conveying direction.

[0048] In a further embodiment of the invention, it can be provided that the fresh air heat exchanger is designed as a thermal oil circuit or as a circuit composite system.

[0049] Such a design of the fresh air heat exchanger is particularly advantageous when the oxidation device is located too far from the treatment room, for example outside the building, because by means of a thermal oil circuit or a circuit combination system, sensible and latent heat energy can be efficiently transferred from the locally more distant exhaust air stream to the fresh air required for the treatment room.

[0050] Alternatively or additionally, it may be provided that one or more high-temperature additional heating devices or high-temperature additional heating registers are arranged downstream of the oxidation device.

[0051] A high-temperature auxiliary heating device comprises an electric heating element, preferably in the form of a tubular or round-tube heater, or is designed as such, with the heat being generated in a current-carrying heating conductor. This heating conductor is preferably centrally embedded in a highly compacted magnesium oxide layer, thereby achieving high electrical insulation with good heat conduction.

[0052] By means of one or more high-temperature auxiliary heating devices, the cleaned exhaust air or clean gas can be heated to a temperature of 450 °C to 480 °C, thus providing a clean gas temperature for dryer heating that is comparable to that which has been available in treatment plants with the previous use of TAR.

[0053] Such a high-temperature additional heating device is preferably arranged suspended in the treatment plant, thereby avoiding friction caused by acting normal forces, as is the case with a classic horizontal and adjacent arrangement of pipes.

[0054] Several high-temperature additional heating devices are preferably arranged in series, wherein in the case of use of more than one high-temperature additional heating device, these are preferably of the same type, ie in particular with the same surface load of, for example, 1 W / cm 2 up to 2 W / cm 2 , are designed. The use of identical high-temperature auxiliary heating devices minimizes the number of units required for possible replacement.

[0055] The present invention is further based on the object of providing a method which enables a conversion of a treatment plant, in particular an existing treatment plant, into an exhaust air-reduced, electrically heated treatment plant.

[0056] This object is achieved according to the invention by a method according to the independent method claim.

[0057] The conversion method is preferably based on a treatment plant to be converted for the treatment of workpieces, in particular for drying vehicle bodies, which has a conveying direction and comprises the following: a treatment chamber which comprises a plurality of treatment chamber sections, each of which is assigned to a separate recirculation module, each of which comprises a heat exchanger; an exhaust air duct which removes exhaust air from the treatment chamber; a thermal afterburning device, in particular one heated by fossil fuels, for processing, in particular for cleaning, the exhaust air, which is provided for conversion or replacement; a clean gas duct which guides cleaned exhaust air, in particular clean gas; a fresh air heat exchanger which transfers thermal energy contained in the clean gas to fresh air supplied to the treatment plant; and a fresh air supply which supplies fresh air to the treatment chamber via the fresh air heat exchanger.The procedure includes the following steps:.

[0058] Installation of one or more additional heating devices in the clean gas duct and / or the fresh air supply; and a) replacing the thermal treatment device with a regenerative thermal oxidizer; or b) replacing the fresh air heat exchanger with a regenerative thermal oxidizer and converting the thermal afterburner, in particular a fossil-fuel-heated one, for use as a fresh air heat exchanger; or c) replacing the thermal treatment device with a regenerative thermal oxidizer and replacing the recirculation modules with heat exchangers with electrically heated recirculation modules or replacing the heat exchangers of the recirculation modules with electric heating registers.

[0059] The method preferably has one or more of the features and / or advantages described in connection with the conversion kit.

[0060] Preferably, the conversion kit further comprises one or more of the features and / or advantages described in connection with the method.

[0061] In the second alternative of case c), the existing recirculation modules are retained, i.e. preferably left in their position, and the respective heat exchangers are preferably replaced by electric heating registers.

[0062] In one embodiment of the invention, it can be provided that the one or more purely electrically operated, hydrogen-operated or thermal oil-operated additional heating devices and / or the purely electrically operated, preferably flameless, regenerative thermal oxidation device are connected to a central electrical connection point, in particular a center station.

[0063] In a further embodiment of the invention, it can be provided that, in the case of b), the thermal afterburner, particularly one fueled by fossil fuels, of the treatment plant to be converted continues to be used as a fresh air heat exchanger. In a further embodiment of the invention, it can be provided that, in the case of a) and c), clean gas flows through the clean gas line in the conveying direction.

[0064] In one embodiment of the invention, it can be provided that in the case of b) the clean gas flows through the clean gas guide opposite to the conveying direction.

[0065] In one embodiment of the invention, it can be provided that the exhaust air is passed at least partially or at least approximately completely through the purely electrically operated, preferably flameless, regenerative thermal oxidation device and is heated at least temporarily to a temperature which brings about a chemical conversion of substances contained in the air stream, in particular solvents, and that at least part of the heat temporarily contained in the exhaust air is recuperated, so that the clean gas leaves the purely electrically operated, preferably flameless, regenerative thermal oxidation device at a temperature which lies between an inlet temperature and a temporary maximum temperature.

[0066] Further preferred features and / or advantages of the invention are the subject of the following description and the drawings of exemplary embodiments.

[0067] The figures show:

[0068] Fig. 1 is a schematic representation of a basic structure of a treatment plant;

[0069] Fig. 2 is a schematic representation of a first embodiment of a converted treatment plant;

[0070] Fig. 3 is a schematic representation of a second embodiment of a converted treatment plant;

[0071] Fig. 4 is a schematic representation of a third embodiment of a converted treatment plant; Fig. 5 is a schematic representation of a fourth embodiment of a converted treatment plant;

[0072] Fig. 6 is a schematic representation of a fifth embodiment of a converted treatment plant; and

[0073] Fig. 7 is a schematic representation of the air connection of an oxidation device.

[0074] Identical or functionally equivalent elements are provided with the same reference numerals in all figures.

[0075] A basic structure of a treatment plant, in particular an inventory treatment plant, shown in Fig. 1 and designated as a whole by 100, is used for the treatment of workpieces (not shown), in particular for the drying of vehicle bodies.

[0076] The treatment plant basic structure 100 is in particular a basic structure of a dryer 102 for drying previously coated vehicle bodies.

[0077] The basic treatment plant structure 100 is to be understood as the basis of a treatment plant that is the basis of a conversion or whose components are reused and / or are functionally and / or structurally integrated into the converted plant. Thus, all components of the basic treatment plant structure 100 are also to be understood as being contained in a treatment plant, in particular an existing treatment plant.

[0078] The basic treatment plant structure 100 comprises a treatment room 104 and a post-treatment room 106.

[0079] The treatment room 104 comprises several treatment room sections 108.

[0080] The treatment room sections 108 are assigned to several separate recirculation modules 110 of the treatment system 100. The recirculation modules 110 each circulate a local recirculation air flow 112 in a local recirculation duct 114 through the respectively assigned treatment room section 108.

[0081] The recirculation modules 110 each preferably comprise a fan and a heat exchanger.

[0082] The workpieces to be treated, in particular vehicle bodies, are conveyed through the treatment chamber 104 and the post-treatment chamber 106 along a conveying direction 116.

[0083] The treatment room 104 further comprises an inlet lock 118 and / or an outlet lock 120, which are supplied with preferably preheated fresh air via a fresh air duct 122 to form an air silhouette.

[0084] It is also conceivable that the fresh air duct 122 is additionally or alternatively connected to at least one of the recirculation modules 110 or supplies at least one recirculation module 110 with fresh air.

[0085] Exhaust air is discharged from the treatment room 104, preferably centrally, via an exhaust air duct 124.

[0086] Treated exhaust air or clean gas is passed through a clean gas duct 126.

[0087] The clean gas guide 126 is thermally coupled to the recirculation modules 110 so that the thermal energy contained in the clean gas can be transferred to the local recirculation air flows 112.

[0088] The post-treatment chamber 106 adjoins the treatment chamber 104 in the conveying direction 116.

[0089] However, it is also conceivable that a cooling zone (not shown) is arranged between the post-treatment room 106 and the treatment room 104, in which the treated workpieces are actively and / or passively cooled down.

[0090] The aftertreatment chamber 106 comprises several aftertreatment chamber sections 128. A fresh air heat exchanger 130 is assigned to the aftertreatment chamber 106, which transfers the thermal energy contained in an exhaust air stream 132 to a supplied fresh air stream 134. However, it is probably more common to mix a partial stream from the exhaust air stream 132 into the fresh air stream 134.

[0091] A preheated fresh air stream 136 is supplied to one of the aftertreatment chamber sections 128 from the fresh air heat exchanger 130.

[0092] A recirculating air flow 138 is formed between the aftertreatment chamber sections 128.

[0093] After transferring at least a portion of the thermal energy, the exhaust air stream 132 is discharged downstream of the fresh air heat exchanger 130 as a cooled exhaust air stream 140. If exhaust air is admixed with the fresh air stream, the non-reused portion of the exhaust air exits the treatment plant 100 via the roof.

[0094] The basic structure of a treatment plant 100 shown in Fig. 1 forms the basis in Figs. 2 to 6 from which the conversion components or conversion process steps are described.

[0095] The basic structure 100 or the plant infrastructure of the existing treatment plant and the corresponding components that will continue to be used after the conversion are shown in Figures 1 to 6 as dashed symbols or dashed lines. The schematic position of the components that will be replaced or exchanged during the conversion is shown in the figures as dotted symbols or dotted lines. Furthermore, the components of the basic treatment plant structure 100 are identified by reference numerals in the range from 100 to 199, while conversion or new components are identified by reference numerals in the range greater than or equal to 200.

[0096] Fig. 2 shows a first embodiment of a converted treatment system 200, which was converted using a conversion kit 202. In the embodiment of the converted treatment system 200 shown in Fig. 2, exhaust air from the treatment chamber 104 is exhausted via the exhaust air duct 124 and fed to a purely electrically operated, preferably flameless, regenerative thermal oxidation device 204.

[0097] The oxidation device 204 replaces a previously used, in particular fossil-fired, thermal afterburning device 142 at the corresponding position.

[0098] Consequently, the post-combustion device 142, which is heated or fired in particular by fossil fuels, is replaced by the electrically heated oxidation device 204, and the temperature increase caused by the cleaning or treatment of the exhaust air in the oxidation device 204 is used to heat the treatment chamber sections 108.

[0099] The treated exhaust air or the clean gas is additionally heated downstream of the oxidation device 204 by an electrically operated additional heating device 206 so that the heat input into the local circulating air streams 112 is sufficient for the treatment of the workpieces, ie in particular the drying of the vehicle bodies.

[0100] If necessary, it is possible to arrange further electrically operated auxiliary heating devices 208 between the recirculation modules 110 in order to be able to provide sufficient heat energy to the local recirculation air flows 112 over the entire length of the treatment room 104.

[0101] The arrangement of further electrically operated auxiliary heating devices 208 between the recirculation modules 110 also avoids excessive heating power and excessively high required surface temperatures at the electrically operated auxiliary heating device 206.

[0102] The clean gas flows through the clean gas duct 126 in the conveying direction 116 and transfers its thermal energy to the supplied fresh air 146 in a fresh air heat exchanger 144, which can in particular be part of the basic treatment plant structure 100, before being discharged via the roof as a cooled clean gas stream 148. Control valves (not shown) are also reused in the area of ​​the fresh air heat exchanger 144 and the recirculation modules 110.

[0103] Preferably, a further electrically operated auxiliary heating device 210 is arranged in the fresh air duct 122 in order to be able to discharge the purified exhaust air or the clean gas after the fresh air heat exchanger as a cooled clean gas stream 148 with a low temperature into the atmosphere or via the roof.

[0104] For this purpose, the enthalpy flow through the roof must be kept as low as possible, which is why it is advisable to simply preheat the fresh air using the fresh air heat exchanger 144. The remaining, required temperature increase is then achieved by means of the additional electrically operated auxiliary heating device 210 by directly heating the fresh air flow in the fresh air duct 122.

[0105] The electrically operated additional heating device 210 in the fresh air duct 122 also performs a further function, namely the regulation of temperature fluctuations of the fresh air which arise during the necessary, cyclical switching of the flow direction of the individual bed of the oxidation device 204.

[0106] The appropriately tempered fresh air is finally supplied preferably via the fresh air supply 122 to the inlet lock 118 and / or the outlet lock 120 and from there circulated in the local recirculating air flows 112 of the treatment room sections 110.

[0107] Fig. 3 shows a second embodiment of the treatment plant 200 converted with a conversion kit 202.

[0108] In this embodiment, the exhaust gas duct 124 guides the exhaust gas discharged from the treatment chamber 104 through the purely electrically operated, flameless, regenerative thermal oxidizer 204, which now replaces the fresh air heat exchanger 144. Also arranged downstream of the oxidizer 204 is the electrically operated auxiliary heating device 206, which further heats the clean gas after the oxidizer 204.

[0109] Due to the alternative exchange position within the treatment plant 200, the clean gas flows downstream of the oxidation device 204 or the electrically operated additional heating device 206 through the clean gas guide 126 against the conveying direction 116, wherein here too the thermal energy of the clean gas guided in the clean gas guide 126 is transferred to the local recirculating air streams 112 by means of the heat exchangers of the recirculating air modules 110.

[0110] Likewise, it is preferably also provided in the second embodiment that further electrically operated additional heating devices 208 are arranged along the clean gas duct, ie in particular between the recirculation modules 110.

[0111] As an alternative to the first embodiment, the thermal post-combustion device 142, which is heated in particular by fossil fuels and has previously been operated in an existing treatment plant, is not completely replaced but converted, i.e., the post-combustion is shut down and the internal heat exchanger of the post-combustion device 142 is used as a fresh air heat exchanger 150 to transfer the remaining thermal energy of the clean gas downstream of the recirculation modules 110 to the required, supplied fresh air stream 152. Thus, the generally high-quality and highly effective heat exchanger of the post-combustion device 142 can be reused.

[0112] The clean gas cooled as a result of the heat transfer is discharged into the atmosphere or via the roof as cooled clean gas stream 154.

[0113] The preheated fresh air is increased downstream of the fresh air heat exchanger 150 by means of the further additional device 210 to the temperature which is preferably required for the inlet lock 118 and / or outlet lock 120.

[0114] As a result of the conversion, the oxidation device 204 replaces the fresh air heat exchanger 144 of an existing system at its original position, whereas the thermal afterburning device 142, which is heated in particular by fossil fuels, remains in its position with minimal effort and at reduced costs and is merely converted so that its internal heat exchanger can be used as a fresh air heat exchanger 150.

[0115] However, the reversal of the flow direction in the clean gas duct 126 requires an adaptation of the exhaust air duct 124, which must be extended by a conversion exhaust air duct 212 so that the exhaust air can be guided to the alternative installation position of the oxidation device 204 instead of the original fresh air heat exchanger 144.

[0116] It is also conceivable that a pretreatment room is arranged upstream of the treatment room 104, with respect to the conveying direction 116, in which pretreatment room the workpieces are pretreated in one or more pretreatment room sections, each pretreatment room section being assigned a separate recirculation module.

[0117] The pretreatment room may have its own inlet lock and / or outlet lock or intermediate lock to which fresh air is supplied.

[0118] With regard to a converted treatment plant 200, it may be necessary to arrange further electrically operated auxiliary heating devices 208 on or in the clean gas duct 126 in order to be able to transfer sufficient thermal energy for the heat transfer from the clean gas to the local circulating air flows 112 in the area of ​​the pretreatment room sections.

[0119] However, the required temperature level in the pretreatment room is generally lower than in the treatment room, which is why additional electrically operated auxiliary heating devices 208 between the recirculation modules 110 assigned to the pretreatment room sections may be unnecessary.

[0120] Otherwise, the conversion of an existing treatment plant with a pre-treatment room is analogous to a plant without pre-treatment, especially since the air and gas ducts required for the pre-treatment room are already in place.

[0121] The third embodiment of a treatment plant 200 converted with a conversion kit 202, shown in Fig. 4, differs from the first embodiment in that the thermal afterburning device 142, which is heated in particular by fossil fuels, is also replaced by a purely electrically operated, flameless, regenerative thermal oxidizer 204, but in a different position.

[0122] The original afterburner device 142 is either shut down and bridged in the position indicated in Fig. 4 or removed from this position.

[0123] The oxidation device 204 is arranged downstream of the recirculation modules 110 and upstream of the fresh air heat exchanger 144.

[0124] The installation of the oxidation device 204 at a different position than that of the original afterburning device 142 can, for example, be due to space reasons, which also means that the space volume freed up at the position of the original afterburning device 142 can be used, for example, for the transformer infrastructure, ie in particular for an integrated unit comprising a central electrical heat generation and a central voltage transformation.

[0125] In the third embodiment, as in the first embodiment or in contrast to the second embodiment, the exhaust air is guided in the conveying direction 116 through the clean gas guide 126, wherein an electrically operated additional heating device 206 downstream of the treatment chamber 104 and / or further electrically operated additional heating devices 208 are also provided between the recirculation modules 110 in order to additionally heat the exhaust air flow and thus ensure that the thermal energy input into the local recirculation air flows 112 is sufficient for the workpiece treatment.

[0126] Fig. 5 shows a fourth embodiment of an existing treatment plant 200 converted with the conversion kit 202.

[0127] The fourth embodiment is to be understood as a variant of the third embodiment shown in Fig. 4, wherein in the fourth embodiment it is assumed that the oxidation device 204 is to be arranged only very far away from the treatment room 104, for example outside a building boundary 156.

[0128] Utilizing the exhaust air enthalpy flow in the fresh air heat exchanger 144 would therefore require a high expenditure in terms of additional lengths in the exhaust air duct, ie additional duct length, and might also require additional insulation of the exhaust air duct downstream of the recirculation modules 110.

[0129] For this reason, a thermal oil circuit 213 or a closed-loop system (KVS) is used here, with the aid of which the sensible and latent heat from the locally more distant exhaust air stream, which was discharged from the treatment room 104, can be transferred to the fresh air required for the treatment room, in particular for the inlet lock 118 and / or the outlet lock 120.

[0130] The remaining, necessary temperature increase is again carried out by means of an electrically operated additional heating device 210 as direct heating of the preheated fresh air flow guided in the fresh air duct 122.

[0131] Fig. 6 shows a fifth embodiment of a treatment plant 200 converted by means of the conversion kit 202.

[0132] Comparable, for example, to the first embodiment, in the fifth embodiment the exhaust air is also guided through the exhaust air duct 124 to the purely electrically operated, flameless, regenerative thermal oxidation device 204, wherein the oxidation device 204 replaces the thermal afterburning device 142, which is heated in particular by fossil fuels.

[0133] Likewise, the electrically operated auxiliary heating device 206 is preferably arranged downstream of the oxidation device 204 in order to provide additional heat energy to the clean gas discharged from the oxidation device 204 or to further heat the clean gas. However, the auxiliary heating device 206 is not absolutely necessary if a correspondingly larger auxiliary heating device 210 compensates for the resulting lower preheating of the fresh air. In an exemplary comparison to the first embodiment, however, the clean gas guide 126 is now thermally decoupled from the recirculation modules and accordingly guides the heated clean gas to the fresh air heat exchanger 144 without stepwise heat transfer.

[0134] Instead of the original recirculation modules 110, which each had its own heat exchanger, electrically operated recirculation modules 214 are installed or installed, which decentrally heat the respective local recirculation air flow 112.

[0135] Consequently, the fifth embodiment does not utilize central and indirect heating of recirculating air modules or units via the oxidation device 204. Nevertheless, the temperature increase in the range of approximately 20 K is provided for the fresh air heating in the fresh air heat exchanger 144 as part of the exhaust air cleaning in the oxidation device 204.

[0136] The heating of the local recirculating air flows 112 is carried out, comparable to the installation of a preferably purely electrically operated new system, in a decentralized manner by means of direct electrical heating via the corresponding recirculating air modules 214.

[0137] It is advantageous if the conversion of the recirculation modules 110 is carried out in such a way that only the internal heat exchangers and the control flaps are dismantled, the corresponding inlets and outlets are closed and electrical heating registers are inserted into the recirculation modules to form electrically operated recirculation modules 214.

[0138] Consequently, the vertical displacement of the clean gas guide 126 in Fig. 6 represents only a schematic, thermal decoupling and should not be synonymous with a relocation of the corresponding, real piping.

[0139] In the first, second, fourth, and fifth embodiments, the oxidation device 204 is preferably arranged or installed close to the dryer for the purpose of cleaning the exhaust air from the treatment chamber 104. However, due to the short exhaust air duct 124 between the treatment chamber 104 and the oxidation device 204, dynamic pressure changes are to be expected, which can have a negative impact on the balance of the treatment chamber 104. The reason for this are pressure surges that occur within the oxidation device 204 due to recurring switching processes of the flow across the thermal bed of the oxidation device 204. These switching processes occur depending on the solvent concentration and the temperature, for example, every 3 to 7 minutes. The switching is carried out via poppet valves and is necessary to stabilize the temperature profile across the thermal bed of the oxidation device 204.

[0140] The described switching within the oxidation device 204 generates undesirable pressure surges, which can lead to the treatment chamber 104, in the area of ​​the inlet lock 118 and the outlet lock 120, forcing the dryer atmosphere or the atmosphere of the treatment chamber 104 into the adjacent areas or treatment chamber sections 108, where condensation can occur. To prevent this, it is advantageous if i) the volume flow to be cleaned, which is supplied to the oxidation device 204 via the exhaust air duct 124, is divided, or ii) the recurring pressure surges are buffered by means of a buffer section between the treatment chamber 104 and the oxidation device 204.

[0141] For variant i), it is conceivable that an oxidation device 204 is configured such that the volume flow to be cleaned is divided into two or more smaller-volume flows and passed through this oxidation device 204. Alternatively, two or more oxidation devices 204 are arranged parallel to one another at the location of the oxidation device 204, so that the volume flow to be cleaned can be divided between these two or more oxidation devices 204.

[0142] As a result, the one or more oxidation devices 204 are flowed through by streams of smaller volume, whereby the switching-related pressure surges are reduced in intensity and the atmospheric balance of the treatment chamber 104 is less affected.

[0143] For variant ii), it is conceivable that the cross section or diameter of the exhaust air duct 124, which may be formed, for example, by a channel, is widened from the treatment chamber 104 to the oxidation device 204. For example, the diameter of the exhaust air duct 124 could be increased at a volume flow of approximately 12,000 Nm 3 / h over a length of 6 m from 0.6 m to 1.5 m.

[0144] In Fig. 6, the air connection of an oxidation device 204 is shown schematically.

[0145] The exhaust air to be cleaned from the treatment room 104 is fed to the oxidation device 204 via the exhaust air duct 124, wherein, for example, the exhaust air from a pre-dryer 216 can be fed to the exhaust air duct 124 via a pre-dryer exhaust air duct 218.

[0146] The combined exhaust air from the treatment chamber 104 and the pre-dryer 216 is conveyed by means of a first fan 220 in the direction of the oxidation device 204, wherein said exhaust air is initially guided downstream of the first fan 220 into a buffer channel 222.

[0147] The volume flow from the buffer channel 222 towards the oxidation device is controlled and / or regulated via a valve device 224.

[0148] A second fan (not shown) is associated with the oxidizer 204 and is preferably located upstream thereof. All internal pressure losses, such as 4,000 Pa to 6,000 Pa at 20°C, of ​​the oxidizer 204 are absorbed by this second fan.

[0149] A third fan 226 is arranged downstream of the oxidizer and upstream of the auxiliary heater 206 in the clean gas duct 126. This third fan 226 overcomes all clean gas pressure losses downstream of the oxidizer 204, such as 4,000 Pa to 7,000 Pa at 20°C.

[0150] For example, in the event of a malfunction of the oxidation device 204, a bypass duct 228 branches off from the exhaust air duct 124 downstream of the buffer channel 222 and is fed to the clean gas duct 126, wherein the volume flow of the bypass duct 228 can be controlled and / or regulated via a further valve device 230. To coordinate the respective volume flows, the valve device 224 of the exhaust air duct and the valve device 230 of the bypass duct 228 are coupled to one another, preferably electrically.

[0151] Furthermore, purge air for temperature control and / or regulation of the thermal bed of the oxidation device 204 can be supplied to a separate chimney 234 via a purge air duct 232, wherein the volume flow can also be controlled and / or regulated via a further valve device 236.

[0152] Fresh air, such as hall air or ambient air, for the oxidation process is also supplied to the oxidation device 204 via a fresh air duct 238, the volume flow of which can be controlled and / or regulated via a further valve device 240.

[0153] The valve device 236 of the purge air guide 232 and the valve device 240 of the fresh air guide 240 are also preferably connected to one another, in particular electrically, to coordinate the respective volume flows.

[0154] List of reference symbols

[0155] Treatment plant basic structure

[0156] Dryer basic structure

[0157] treatment room

[0158] Aftercare room

[0159] Treatment room section

[0160] Recirculation module local recirculation flow local recirculation flow

[0161] Conveying direction

[0162] Inlet lock

[0163] Outlet lock

[0164] Fresh air supply

[0165] Exhaust air duct

[0166] Clean gas flow

[0167] Post-treatment room sections

[0168] Fresh air heat exchanger

[0169] Exhaust air flow supplied fresh air flow preheated fresh air flow

[0170] Recirculating air flow cooled exhaust air flow

[0171] Afterburner device

[0172] Fresh air heat exchanger supplied fresh air cooled clean gas stream

[0173] Fresh air heat exchanger

[0174] Fresh air flow cooled clean gas flow

[0175] Building boundary converted treatment plant

[0176] Conversion kit regenerative thermal oxidizer electrically operated auxiliary heater electrically operated auxiliary heater electrically operated auxiliary heater conversion exhaust air duct

[0177] Thermal oil circuit electrically operated recirculation modules

[0178] Pre-dryer

[0179] Pre-dryer exhaust air duct first fan

[0180] Buffer channel

[0181] Valve device third fan

[0182] Bypass routing

[0183] Valve device

[0184] Purge air duct

[0185] Chimney

[0186] Valve device

[0187] Fresh air supply

[0188] Valve device

Claims

Claims Conversion kit (202) suitable for converting a treatment plant, in particular an existing treatment plant, for the treatment of workpieces, especially drying of vehicle bodies, wherein the conversion kit (202) comprises: one or more auxiliary heating devices (206, 208, 210) suitable for heating a clean gas guided in a clean gas duct (126) and / or fresh air guided in a fresh air duct (122); and a) a regenerative thermal oxidation device (204) as a replacement for a thermal afterburner device (142), in particular one heated by fossil fuels; or b) a regenerative thermal oxidation device (204) as a replacement for a fresh air heat exchanger (144) and a converted thermal afterburner device (142), in particular one heated by fossil fuels, for use as a fresh air heat exchanger (150);or c) a regenerative thermal oxidizer (204) as a replacement for a thermal afterburner (142), in particular one heated by fossil fuels, and electrically heated recirculating air modules (214) as a replacement for recirculating air modules (110) with heat exchangers or converted recirculating air modules (214) with electric heating elements instead of heat exchangers. Conversion kit (202) according to claim 1, characterized in that the treatment plant to be converted has a conveying direction (116) and comprises the following: a treatment chamber (104) comprising several treatment chamber sections (108), each of which is assigned to a separate recirculating air module (110), each of which comprises a heat exchanger; an exhaust air duct (124) which discharges exhaust air from the treatment chamber (104); the thermal afterburner (142), in particular one heated by fossil fuels, for conditioning, in particular for cleaning, the exhaust air, which is provided for conversion or replacement; A clean gas guide (126) which carries purified exhaust air, in particular clean gas, wherein the clean gas guide (126) preferably runs at least approximately parallel to the conveying direction (116); and a fresh air supply (122) which supplies fresh air to the treatment chamber (104). Conversion kit (202) according to claim 2, characterized in that the treatment plant to be converted further comprises a fresh air heat exchanger (144) which is designed to transfer heat energy contained in the clean gas to the fresh air (146) supplied to the treatment plant. Conversion kit (202) according to any one of claims 1 to 3, characterized in that the one or more auxiliary heating devices (206, 208, 210) are purely electrically operated, hydrogen-operated, or thermal oil-operated auxiliary heating devices.Conversion kit (202) according to any one of claims 1 to 4, characterized in that the regenerative thermal oxidation device (204) is a purely electrically operated, in particular flameless, regenerative thermal oxidation device. Conversion kit (202) according to any one of claims 1 to 5, characterized in that one or more purely electrically operated auxiliary heating devices (206, 208, 210) and / or the purely electrically operated, in particular flameless, regenerative thermal oxidation device (204) are connectable to a central electrical connection point, in particular a center station. Conversion kit (202) according to any one of claims 1 to 6, characterized in that the regenerative thermal oxidation device (204) comprises a fan for conveying an airflow.Conversion kit (202) according to one of claims 1 to 7, characterized in that in c) by means of the clean gas guide (126) the clean gas can be guided exclusively to the fresh air heat exchanger (144). Conversion kit (202) according to any one of claims 1 to 7, characterized in that, in a) and c), the clean gas guide (126) is permeable in the conveying direction (116). Conversion kit (202) according to any one of claims 1 to 7, characterized in that, in b), the clean gas guide (126) is permeable against the conveying direction (116). Conversion kit (202) according to any one of claims 1 to 10, characterized in that the regenerative thermal oxidation device (204) is arranged at one end of the clean gas guide (126) with respect to the conveying direction (116). Conversion kit (202) according to any one of claims 1 to 11, characterized in that the fresh air heat exchanger (144) is designed as a thermal oil circuit (212) or as a closed-loop system. Method for converting a treatment plant, in particular an existing treatment plant, for the treatment of workpieces, in particular drying of vehicle bodies.wherein the treatment plant to be converted has a conveying direction (116), and wherein the treatment plant to be converted comprises the following: a treatment chamber (104) comprising several treatment chamber sections (108), each of which is assigned to a separate recirculating air module (110), each of which comprises a heat exchanger; an exhaust air duct (124) which discharges exhaust air from the treatment chamber (104); a thermal afterburner (142), in particular fossil-fuel heated, for conditioning, in particular cleaning, the exhaust air, which is intended for conversion or replacement; a clean gas duct (126) which carries cleaned exhaust air, in particular clean gas; a fresh air heat exchanger (144) which transfers the thermal energy contained in the clean gas to the fresh air (146) supplied to the treatment plant; and, a fresh air supply (122) which supplies fresh air to the treatment room (104) via the fresh air heat exchanger (144); wherein the method comprises the following steps: Installing one or more purely electrically operated auxiliary heating devices (206, 208, 210) in the clean gas flow (126) and / or the fresh air supply (122); and a) replacing the thermal afterburner (142), which is particularly fossil fuel-heated, with a purely electrically operated, preferably flameless, regenerative thermal oxidizer (204); or b) replacing the fresh air heat exchanger (144) with a purely electrically operated, preferably flameless, regenerative thermal oxidizer (204) and converting the thermal afterburner (142), which is particularly fossil fuel-heated, for use as a fresh air heat exchanger (150); or c) replacing the thermal afterburner (142), which is particularly fossil fuel-heated, with a purely electrically operated, preferably flameless,regenerative thermal oxidation device (204) and replacement of the recirculating air modules (110) with heat exchangers by electrically heated recirculating air modules (214) or replacement of the heat exchangers of the recirculating air modules (110) by electric heating elements. Method according to claim 13, characterized in that one or more purely electrically operated, hydrogen-operated or thermal oil-operated auxiliary heating devices (206, 208, 210) and / or the purely electrically operated, preferably flameless, regenerative thermal oxidation device are connected to a central electrical connection point, in particular a central station. Method according to claim 13 or 14, characterized in that in b) the thermal afterburner device (142) of the treatment plant to be converted, which is in particular fossil fuel-heated, is reused as a fresh air heat exchanger (150). A method according to claim 13 or 14, characterized in that in a) and c) the clean gas guide (126) is flowed through by the clean gas in the conveying direction (116). A method according to claim 13 or 14, characterized in that in b) the clean gas guide (126) is flowed through by the clean gas against the conveying direction (116).A method according to one of claims 13 to 17, characterized in that the exhaust air is passed at least partially or at least approximately completely through the purely electrically operated, preferably flameless, regenerative thermal oxidation device (204) and is thereby heated at least temporarily to a temperature which causes a chemical conversion of substances contained in the air stream, in particular solvents, and that at least a part of the heat temporarily contained in the exhaust air is recuperated, so that the clean gas leaves the purely electrically operated, preferably flameless, regenerative thermal oxidation device (204) at a temperature which lies between an inlet temperature and a temporary maximum temperature.

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