Coating method and coating system for coating an object

Abstract

The invention presented relates to a coating method (100) for coating an object with a coating material, the coating method (100) comprising: - coating (101) the object with the coating material, - drying (103) the coated object, - condensing solvent from a fluid which arises in the process of coating the object, in a solvent recovery process (105), - evaporating (107) a refrigerant by means of thermal energy released during the solvent recovery process, - compressing (109) the refrigerant in order to maximize a temperature of the refrigerant, - transferring (111) thermal energy stored in the compressed refrigerant to a working fluid which is used in the process of coating the object.

Description

[0001] Description

[0002] Coating process and coating system for coating an object

[0003] The invention relates to a coating method and a coating system for coating an object with a coating material according to the appended claims.

[0004] Coating processes are used to apply thin layers of coating material to an object. This can be done, for example, by pulling the object through a bath of coating material.

[0005] A coated object is then dried to prevent the coating material from running off and to ensure complete coverage of the object's surface with coating material.

[0006] For example, fans are used for drying, which are very energy-intensive and, as a result, harmful to the climate.

[0007] EP 3 974 057 A1 describes a coating process for an object with a polymer material comprising a monomer. A gas consumed during the coating process is regenerated by a gas regeneration system, thus minimizing the consumption of the gas, e.g., carbon dioxide.

[0008] EP 1 066240 B1 describes a process for the production of acrylic acid and acid esters in which condensation energy released during production is fed back into the production process.

[0009] It is therefore an object of the present invention to enable a cost- and energy-efficient coating process that generates a minimum of climate-damaging emissions.

[0010] The above object is achieved by the subject matter of the independent claims. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Thus, according to a first aspect of the invention, a coating method for coating an object with a coating material is presented.

[0011] The presented coating method includes coating the object with the coating material, drying the coated object, condensing solvent from a fluid generated during coating of the object in a solvent recovery process, evaporating a refrigerant using thermal energy released during the solvent recovery process, compressing the refrigerant to maximize a temperature of the refrigerant, and transferring thermal energy stored in the compressed refrigerant to a working fluid used in coating the object.

[0012] By compressing the refrigerant to maximize a temperature in the refrigerant, in particular using a heat pump, an energy efficiency of the presented coating process is maximized.

[0013] In the context of the present invention, a solvent recovery process is understood to mean a process in which solvent is separated from a coating material in order to reuse the solvent. For this purpose, a mixture of coating material and solvent can, for example, be heated to such an extent that the solvent evaporates, releasing thermal energy in the form of so-called condensation energy upon condensation of the solvent.

[0014] In this context, a heat exchanger is understood to be an object that conducts heat well, such as a heat exchanger, in particular a plate heat exchanger.

[0015] The presented invention is based on the transfer of thermal energy, in particular condensation energy, released during a solvent recovery process to a drying apparatus used to dry the object, such as a drying oven or a heater of an area used to dry the object.

[0016] When previously evaporated solvent condenses, condensation heat or condensation enthalpy is released, which can be absorbed or dissipated, for example, by a plate heat exchanger where the condensate accumulates. This heat is transferred to the drying apparatus and the solvent condensation process is supported or accelerated. Accordingly, the energy released in the solvent recovery process is not discarded by the coating process presented here, but is reused, so that at least a portion of the energy used to operate the drying apparatus is provided by the solvent recovery process.

[0017] The coating process can be a cyclic coating process or a continuous process.

[0018] To minimize the additional energy that must be supplied to the drying apparatus or heating system, for example, from a power plant, and which is therefore potentially harmful to the climate, the invention provides that the thermal energy released in the solvent recovery process is transferred to a refrigerant. This evaporates the refrigerant. The refrigerant is then compressed or liquefied to maximize its energy content, e.g., to heat the refrigerant to a predetermined temperature.

[0019] Finally, the thermal energy stored in the coolant is used in the coating of the object, for example by supplying the drying apparatus or the heater with the thermal energy.

[0020] It can be provided that the thermal energy released during the solvent recovery process is transferred by means of a first heat exchanger to a first working fluid flowing in a first circuit and the thermal energy is transferred via a second heat exchanger from the first working fluid to the refrigerant in order to evaporate the latter, wherein the refrigerant is compressed by means of a compressor and wherein thermal energy from the refrigerant is transferred via a third heat exchanger to a second working fluid, and the object is dried by means of thermal energy stored in the second working fluid.

[0021] Three fluid circuits allow efficient flow through three thermally different areas, so that thermal energy is collected and distributed throughout the respective areas.

[0022] The first working fluid and / or the second working fluid may comprise thermal oil or consist of thermal oil.

[0023] It may further be provided that, in the event that a temperature of the refrigerant is below a predetermined threshold value, additional thermal energy is provided by a heating system in order to heat the third region to a temperature which is greater than the threshold value.

[0024] In case the energy released by the solvent recovery process and any thermal energy provided by the densification process is not sufficient to operate the drying apparatus, a heating system can be used to provide additional thermal energy.

[0025] The heating system can, for example, be supplied with energy by a power plant, or can itself be a heating system, in particular a combustion heating system for burning fossil fuels.

[0026] In particular, the heating system may be electric heating and include a number of solar thermal modules so that the additional thermal energy is provided without emitting greenhouse gases.

[0027] It can further be provided that the thermal energy released during the solvent recovery process is transferred to the refrigerant via a precondensation heat exchanger thermally coupled to a precondensation region and / or a postcondensation heat exchanger thermally coupled to a postcondensation region, and thermal energy is transferred from the compressed refrigerant to a working fluid via a working heat exchanger, wherein the working fluid is used to heat the object.

[0028] Different condensation zones with different temperatures can provide different supply routes for supplying the refrigerant with thermal energy, so that, for example, a warmer pre-condensation zone is thermally coupled to the refrigerant via a heat exchanger in order to accumulate the thermal energy provided in the pre-condensation zone through compression, and a colder post-condensation zone directly tempers the heat exchanger via a stream of a gas mixture.

[0029] Optionally, the cooler post-condensation zone can also be thermally coupled directly to the third zone via a stream of a gas mixture, so that the cooler gas mixture from the post-condensation zone is introduced, for example, into a first heating stage or pre-heating stage, which precedes a main heating stage in which a predetermined maximum temperature is reached, in order to slowly heat the object to the maximum temperature. It can also be provided that the refrigerant is compressed using a heat pump.

[0030] A heat pump converts electrical energy into thermal energy. More thermal energy is provided than electrical energy consumed, thus minimizing the amount of electrical power required to heat the refrigerant.

[0031] In particular, the compression of the refrigerant can be carried out by a compressor of a heat pump.

[0032] It can further be provided that the first working fluid is circulated in a first circuit, the refrigerant is circulated in a second circuit and the second working fluid is circulated in a third circuit, wherein the first circuit is thermally coupled to the second circuit only via the second heat exchanger, wherein the second circuit is coupled to the third circuit only via the third heat exchanger.

[0033] Three separate circuits, each with its own circulating thermal fluid, can be used to create three zones that are thermally separated or simply connected by appropriate heat exchangers. Accordingly, different temperatures can be set in each zone.

[0034] According to a second aspect, the presented invention relates to a coating system for coating an object with a coating material.

[0035] The coating system presented comprises a first region configured to carry out a solvent recovery process, a second region configured to evaporate a refrigerant by means of thermal energy generated in the first region and to compress the refrigerant in order to maximize a temperature of the refrigerant, and a third region configured to dry the object by means of thermal energy stored in the compressed refrigerant, wherein the first region is fluidly coupled to the third region.

[0036] The coating system presented is used in particular to carry out the coating process presented.

[0037] It can be provided that a first circuit is formed in the first region, a second circuit is formed in the second region and a third circuit is formed in the third region, wherein the first circuit comprises a first pump for circulating a first working fluid in the first circuit, a first heat exchanger for transferring thermal energy released during a solvent recovery process carried out in the first region to the first working fluid and a second heat exchanger for transferring thermal energy from the first working fluid to a refrigerant of the second circuit, wherein the second circuit comprises a second pump for circulating the refrigerant in the second circuit,a compressor for compressing the refrigerant and a third heat exchanger for transferring thermal energy stored in the refrigerant to a second working fluid of the third circuit, and wherein the third circuit comprises a third pump for circulating the second working fluid in the third circuit and a fourth heat exchanger for providing thermal energy for a drying process for drying the object after a coating process from the second working fluid.

[0038] Three independent circuits, in each of which thermal fluid is circulated by a pump and which are only coupled to each other by heat exchangers, enable the formation of three areas in which different thermal conditions exist.

[0039] The second circuit serves in particular to transfer thermal energy from the first area to the third area.

[0040] It can be provided that the first working fluid and / or the second working fluid comprise or comprise thermal oil and / or hot water and / or steam.

[0041] Thermal oil has proven to be a particularly suitable and safe thermal fluid.

[0042] It can further be provided that the first region comprises a pre-condensation heat exchanger thermally coupled to a pre-condensation region and / or a post-condensation heat exchanger thermally coupled to a post-condensation region, wherein the pre-condensation heat exchanger and / or the post-condensation heat exchanger are configured to transfer thermal energy accumulating in the first region to the refrigerant, and wherein the second region comprises a refrigerant heat exchanger configured to transfer thermal energy stored in the refrigerant to a fluid flowing in a fluid channel to the third region. It can further be provided that the second region comprises a heat pump, wherein the heat pump comprises the compressor.

[0043] A heat pump arranged in the second area maximizes the efficiency of converting the electricity consumed by the coating system into thermal energy provided by the coating system or to coated objects.

[0044] In particular, the refrigerant heat exchanger can be designed as an integral component of the heat pump.

[0045] Further advantages, features, and details of the invention will become apparent from the following description, in which several embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. The invention is illustrated in the following figures:

[0046] Figure 1 shows a possible design of the coating process presented,

[0047] Figure 2 shows a possible design of the coating system presented.

[0048] Figure 3 shows another possible design of the coating system presented.

[0049] Figure 1 shows a coating method 100 for coating an object with a coating material.

[0050] The coating method 100 comprises a coating step 101 in which the object is coated with the coating material and a drying step 103 in which the coated object is dried.

[0051] The coating step 101 and the drying step 103 are repeated in particular in a cyclic process for a plurality of objects in a third area.

[0052] In a solvent recovery process, solvent from a fluid generated during the coating of the object is condensed in a first area.

[0053] Energy released during the solvent recovery process (105) is evaporated in an evaporation step 107 using thermal energy released during the solvent recovery process. For this purpose, the thermal energy from the solvent recovery process can, for example, be transferred to the refrigerant by means of a heat exchanger.

[0054] In a compression step 109, the refrigerant is then compressed by means of a compressor so that thermal energy or working energy accumulates in the refrigerant.

[0055] Finally, thermal energy from the coolant is transferred in a transfer step 111, e.g. via another heat exchanger, to a working fluid that is used in coating the object

[0056] Figure 2 shows a coating system 200 for coating an object with a coating material.

[0057] The coating system 200 comprises a first region 201 in which a first circuit 203 is formed, a second region 205 in which a second circuit 207 is formed, and a third region 209 in which a third circuit 211 is formed.

[0058] In the first area 201, a solvent recovery process is carried out in which solvent is condensed in order to separate it from a coating material.

[0059] Condensation energy is transferred from the solvent recovery process by means of a first heat exchanger 213 to a first working fluid circulated in the first circuit 203 by a first pump 215.

[0060] The first circuit 203 is thermally coupled to the second circuit 207 via a second heat exchanger 217.

[0061] In the present case, the second heat exchanger 217 forms the evaporator side of a heat pump formed by the second region 205.

[0062] The thermal energy coupled into the first circuit 203 by the first heat exchanger 213 is coupled into the second circuit 207 by the second heat exchanger 217, so that a refrigerant circulated in the second region 205 by a compressor 219 is heated with thermal energy from the first region 201 and evaporates at the second heat exchanger 217 in the second region 205. The gaseous refrigerant is compressed by a compressor 219 from a low pressure level to a higher pressure level. The compression increases the temperature of the refrigerant, the pressure level, and, consequently, the energy content of the refrigerant.

[0063] Via a third heat exchanger 223, energy is transferred from the refrigerant to a second working fluid, e.g. thermal oil, circulated in the third circuit 211 by a third pump 225 as preheating.

[0064] The refrigerant is then released through an expansion valve 227. This cools the refrigerant and continues the continuous process.

[0065] The third pump 225 transports the second working fluid through a piping system toward a fourth heat exchanger 229 to a preheater for the coating process. There, the energy is fed into a respective segment of a coating furnace at the maximum possible temperature before a post-heater regulates the temperature to the target temperature of the respective segment.

[0066] Figure 3 shows a coating system with a first area 201, a second area 205 and a third area 209.

[0067] In the first region, a solvent recovery process takes place in which solvent condenses out of a fluid flowing via a channel 243 from the third region 209 into the first region 201, thereby providing thermal energy.

[0068] A pre-condensation region 231 and a post-condensation region 235 are formed, with a higher temperature being reached in the pre-condensation region than in the post-condensation region 235.

[0069] The pre-condensation region 231 is thermally coupled to refrigerant flowing in a heat pump 245 via a pre-condensation heat exchanger 233 and the post-condensation region 235 is thermally coupled to refrigerant flowing in a heat pump 245 via a post-condensation heat exchanger 237, so that thermal energy provided in the pre-condensation region 231 and the post-condensation region 235 is transferred to the refrigerant and accumulated by the heat pump 245.

[0070] Warm and humid air from the post-condensation area 235 can be directed via optional air ducts 247 and 249 to a refrigerant heat exchanger 239 or into the third area 209. The refrigerant heat exchanger 239 transfers thermal energy accumulated in the refrigerant to a fluid flow, in particular an air flow, which is directed via a fluid duct 251 into the third area 209 to dry an object. The refrigerant is then expanded via an expansion valve 253, causing it to cool and liquefy, allowing the process to continue continuously.

[0071] The refrigerant heat exchanger 239 preheats a partial flow of the gas mixture from the outlet of the solvent recovery in the first area 201 for a number of hot sections 255 in the coater of the third area 209 to the maximum possible temperature level before it is subsequently heated to the target temperature by a final heating stage 257.

[0072] A number of cold sections 259 of the coater in the third area 209 are supplied directly with the gas mixture from the outlet of the solvent recovery in the first area 201 and heated to the target temperature in a further heating stage 261.

[0073] List of reference symbols

[0074] Coating process

[0075] Coating step

[0076] Drying step

[0077] Solvent recovery process

[0078] Coating system first area first circuit second area second circuit third area third circuit first heat exchanger first pump second heat exchanger

[0079] Compressor third heat exchanger third pump

[0080] Expansion valve

[0081] Fourth heat exchanger

[0082] Pre-condensation area

[0083] Precondensation heat exchanger

[0084] Post-condensation area

[0085] Post-condensation heat exchanger

[0086] Refrigerant heat exchanger

[0087] channel

[0088] heat pump

[0089] air duct

[0090] air duct

[0091] Fluid channel

[0092] Expansion valve hot section

[0093] Heating stage cold section

[0094] Heating stage

Claims

Patent claims 1. A coating method (100) for coating an object with a coating material, the coating method (100) comprising: Coating (101) the object with the coating material, Drying (103) the coated object, Condensing solvent from a fluid produced during coating of the object in a solvent recovery process (105), Evaporating (107) a refrigerant by means of thermal energy released during the solvent recovery process, Compressing (109) the refrigerant to maximize a temperature of the refrigerant, Transferring (111) thermal energy stored in the compressed refrigerant to a working fluid used in coating the object.

2. Coating method (100) according to claim 1, characterized in that the thermal energy released during the solvent recovery process (105) is transferred by means of a first heat exchanger (213) to a first working fluid flowing in a first circuit (203), wherein the thermal energy is transferred from the first working fluid to the refrigerant via a second heat exchanger (217) in order to evaporate the latter, wherein the refrigerant is compressed by means of a compressor (219), wherein thermal energy from the refrigerant is transferred to a second working fluid via a third heat exchanger (223), and the object is dried by means of thermal energy stored in the second working fluid.

3. Coating method (100) according to claim 2, characterized in that, in the event that a temperature of the refrigerant is below a predetermined threshold value, additional thermal energy is provided by a heating system in order to heat the third region to a temperature which is greater than the threshold value.

4. Coating method (100) according to claim 1, characterized in that the thermal energy released during the solvent recovery process (105) is transferred to the refrigerant via a precondensation heat exchanger (233) thermally coupled to a precondensation region (231) and / or a postcondensation heat exchanger (237) thermally coupled to a postcondensation region (235), and thermal energy is transferred from the compressed refrigerant to a working fluid via a working heat exchanger (239), the working fluid being used to heat the object.

5. Coating method (100) according to one of the preceding claims, characterized in that the compression of the refrigerant is carried out by means of a heat pump.

6. A coating system (200) for coating an object with a coating material, the coating system (200) comprising: a first region (201) configured to carry out a solvent recovery process (105), a second region (205) configured to evaporate a refrigerant by means of thermal energy generated in the first region (201) and to compress the refrigerant in order to maximize a temperature of the refrigerant, a third region (209) configured to dry the object by means of thermal energy stored in the compressed refrigerant, the first region (201) being fluidly coupled to the third region (209).

7. Coating system according to claim 6, characterized in that a first circuit (203) is formed in the first region (201), a second circuit (207) is formed in the second region (205), and a third circuit (211) is formed in the third region (209), wherein the first circuit (203) comprises a first pump (215) for circulating a first working fluid in the first circuit (203), a first heat exchanger (213) for transferring thermal energy released during a solvent recovery process (105) carried out in the first region (201) to the first working fluid, and a second heat exchanger (217) for transferring thermal energy from the first working fluid to a refrigerant of the second circuit (207). wherein the second circuit (207) comprises a compressor (219) for circulating and compressing the refrigerant in the second circuit (207) and a third heat exchanger (223) for transferring thermal energy stored in the refrigerant to a second working fluid of the third circuit (211), wherein the third circuit (211) comprises a third pump (225) for circulating the second working fluid in the third circuit (211) and a fourth heat exchanger (229) for providing thermal energy for a drying process for drying the object after a coating process from the second working fluid.

8. Coating system (200) according to claim 7, characterized in that the first working fluid and / or the second working fluid comprise thermal oil and / or heating water and / or steam.

9. Coating system (200) according to claim 6, characterized in that the first region (201) comprises a precondensation heat exchanger (233) thermally coupled to a precondensation region (231) and / or a postcondensation heat exchanger (237) thermally coupled to a postcondensation region (235), wherein the precondensation heat exchanger (233) and / or the Post-condensation heat exchangers (237) are configured to transfer thermal energy occurring in the first region (201) to the refrigerant, wherein the second region (205) comprises a refrigerant heat exchanger (239) which is configured to transfer thermal energy stored in the refrigerant to a fluid flowing in a fluid channel to the third region (209).

10. Coating system (200) according to one of claims 6 to 9, characterized in that the second region (205) comprises a heat pump, wherein the heat pump comprises a compressor (219).

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