Method for producing a binder using thermal energy, and method for drying panels produced using a binder in a drying device

Abstract

The invention relates to a coupled method comprising a method for producing or treating a binder using thermal energy in a first device (100) and a method for drying panels produced using a binder in a second device, which is designed as a drying device (1), wherein exhaust heat generated in the first device is recovered via at least one heat recovery means and is at least partly supplied to the second device, in which the heat is used to dry the panels.

Description

[0001] Method for producing a binder using thermal energy and method for drying boards produced using a binder in a drying device

[0002] The invention relates to a coupled method comprising a method for producing a binder using thermal energy in a first device and a method for drying boards produced using a binder in a second device designed as a drying device, wherein waste heat generated in the first device is recovered via at least one heat recovery means and is at least partially fed to the second device in which it is used to dry the boards.

[0003] During calcination, a building material or binder, particularly a calcium-containing mineral, is heated in the presence of air or in an oxygen-containing atmosphere to dehydrate or condition the mineral. An example of a calcination process is lime burning, in which water, calcium oxide, and carbon dioxide are formed as decomposition products. The calcination processes are similar for magnesite and dolomite. In gypsum production, water of crystallization is extracted from calcium sulfate dihydrate. In clay and porcelain firing, bound water also escapes with the simultaneous sintering of the particles. Calcination is also used in the production of cement and aluminum oxide; rotary kilns are often used for calcination. Binders used in finished building material mixtures or in building panels are also prepared for use by heating in rotary kilns.

[0004] A calcining device will be referred to below as a calciner. For the purposes of the invention, a calciner is understood to mean any form of apparatus suitable for calcination, for example, an indirectly heated rotary kiln, an indirect cooker, a steam-heated calciner, or even a conventional hammer or roller mill when converted to electric heating. All calcination processes require high energy input and high temperatures. In the case of calcined clay, for example, temperatures of over 800°C are reached; in the case of gypsum, for example, temperatures between 150°C and 400°C are used. For example, see WO 2012 / 028251 A1.

[0005] In addition to the energy input, calcination processes usually require the calcined minerals to be actively cooled.

[0006] On the other hand, when drying building panels, such as gypsum boards, plasterboard, gypsum fiberboard, cement boards, and other building material boards, the problem arises that a fuel (i.e., primary energy) is required to heat the drying air, for example, using burners or heating registers, and electrical energy (i.e., secondary energy) is required to supply the air via fans. The use of both primary and secondary energy must be reduced to enable more energy-efficient production of the aforementioned panels.

[0007] DE 26 13 512 A1 discloses a drying process in a drying device in which low primary energy consumption is achieved by utilizing the condensation heat of the exhaust air. This process is designed in two stages. In the first drying stage, drying takes place at high temperature and high humidity, and in the second drying stage at low temperature and low humidity. The drying capacity of the first stage is two to three times that of the second stage, and the second drying stage is heated from the exhaust air of the first drying stage via an intermediary heat exchanger. In both stages, the drying air is supplied using a recirculation process: in the first drying stage, in the form of longitudinal ventilation, and in the second drying stage, in the form of transverse ventilation with a large recirculation mass flow. However, the second stage requires a large recirculation mass flow and thus a high consumption of secondary energy.The aim is to reduce the overall energy consumption in the production of building panels, in particular to make the use of thermal energy more economical and environmentally friendly.

[0008] According to the invention, this object is achieved as stated in claim 1.

[0009] The invention makes it possible to reuse heat energy from the calcination or conditioning device of a building material in order to reduce the overall energy consumption in the production of building material panels.

[0010] According to the invention, waste heat generated in the first device is recovered via at least one heat pump and at least partially fed to the second device in which it is used to dry the panels.

[0011] According to the invention, a significant portion of the thermal energy is supplied to the at least one heat pump, which in turn transfers the thermal energy to a line that is directly or indirectly connected to at least one part or region of a drying device.

[0012] Compared to the process proposed in patent application DE 10 2022 000 627.8, the dryer's residual energy requirement is significantly reduced, preferably halved. The front section of the dryer can be realized with a lightweight shell construction, thus saving material costs.

[0013] Advantageous further developments emerge from the subclaims and the description, in particular in conjunction with the drawings.

[0014] The invention is used in particular in conjunction with a calciner from which heat energy is supplied to the drying device. According to the invention, the same building material is generally prepared, heated, or prepared for a subsequent manufacturing process in the calciner, from which panels are manufactured in another device, which are then dried in the drying device using at least part of the waste heat from the first device. However, the invention also does not preclude the possibility of processing, heating, or drying different building materials or binders in the first and second devices.

[0015] The calciner, for example, is designed as a rotary kiln that is heated directly or indirectly. Alternatively, a cooker is used, which can also be heated directly or indirectly; steam can also be used for heating. Conventional hammer and roller mills can also be used for calcination. High efficiency is achieved when the hammer or roller mills are converted to a

[0016] The invention thus relates to a coupled process in which the building material or the insulating material or the binder is treated by heating in the first device designed as a rotary kiln, wherein the waste heat of the rotary kiln is fed to the at least one heat recovery means, from which it is then fed to the second device.

[0017] Preferably, the coupled method is characterized in that heat is recovered in at least one heat pump by the at least one heat recovery means. The heat pump is arranged in close proximity to the first device and represents a high-temperature heat pump, since the inlet temperature of the air flowing out of the first device is already very high and is raised to an even higher value by the heat pump.

[0018] The heat is transferred from the heat pump to the second device via at least one heat exchanger.

[0019] Preferably, gypsum or cement clinker is burned in the rotary kiln, and boards containing gypsum or cement clinker are dried in the second device.

[0020] It is also advantageous if gypsum boards or cement boards are produced from the gypsum heated in the rotary kiln or cement clinker heated in the rotary kiln in an intermediate process, and if the gypsum boards or cement boards are dried in the second device. The invention thus also includes the use of a portion of the heat lost in the first device for a manufacturing process or a manufacturing step of the intermediate process that precedes the use of the heat in the second device, i.e., the drying device.

[0021] When heated air from the heat recovery means is introduced into the second device, which is designed as a drying device, the energy consumption in the second device is significantly reduced. For example, it is possible to provide 50% to 100% of the energy for the second device through the heat recovery means.

[0022] In a particular embodiment of the invention, energy, for example in the form of heated air, is supplied to at least one front part of the second device, relative to the plate conveying direction.

[0023] Preferably, the method according to the invention is characterized in that the boards pass through a first stage (A) and a second stage (B) in the drying device, wherein the two stages (A, B) each have tiers and the boards are each placed on surfaces formed in tiers and are guided through the drying device in the respective tiers of the two stages (A, B), wherein the boards are brought into contact with high-temperature drying air in the first stage (A) and dried and are dried with drying air of a lower temperature in the second stage (B), wherein the boards are heated at least in the first stage by warm air generated by a heat exchanger, by means of a heat pump, by means of a wet separator, by a burner directly or by means of hot steam or by means of thermal oil or electrically indirectly or by means of low-calorific heat,At most, a single means is provided for recovering heat supplied to the plates in the second stage. Preferably, the front and rear parts of the second device have the same number of floors. According to the invention, the coupled process ensures that the plates are dried by circulating air at least in the first stage. At high temperatures in the range between 90°C and 160°C, preferably between 120°C and 140°C, the air absorbs so much moisture that the dew point lies between 60°C and 99°C, preferably between 75°C and 90°C. In this way, it is possible to convert large quantities of water into the liquid state by cooling the water gas-saturated air and to recover the enthalpy of the phase transition via condensation in a heat exchanger in the region of the second device.

[0024] Preferably, in one embodiment, the method is characterized in that the plates are dried at least substantially by the use of nozzle boxes, at least in the region of the first stage (A).

[0025] According to one embodiment, the plates are dried in the second stage (B) by drying air at a temperature of 20 to 90 °C.

[0026] According to one embodiment, the exhaust air of the first stage (A) is passed into a heat exchanger (31) for preheating the drying air of the second stage (B).

[0027] It is advantageous if the panels are first dried in a pre-drying stage prior to the first stage (A), then in the first stage (A) and finally in the second stage (B).

[0028] It is also advantageous if the plates in the stages (A, B) are each transported through sections (2) by means of separate conveyor devices for each stage (A, B).

[0029] In a further embodiment, the boards in the second stage (B) are guided in a higher number of tiers than in the first stage (A); stages (A, B) can, for example, run above one another or next to one another. When drying boards, especially cement- and gypsum-containing building boards, the boards conveyed through a dryer are brought into contact with heated air.

[0030] The drying air can be supplied by longitudinal ventilation, transverse ventilation, or cross ventilation using nozzle boxes equipped with nozzles. With longitudinal ventilation, the drying air is supplied at one end of the dryer or, if it is divided into several zones, at one end of a zone and exhausted at the opposite end.

[0031] With cross ventilation, the air is introduced at several points along the sides of the dryer and discharged at the opposite sides, enabling more intensive drying within the dryer. Particularly intensive drying is achieved with cross ventilation via nozzles through the jet dryers in impingement flow.

[0032] Preferably, the boards are dried in the first stage A using drying air at a temperature of 90 to 1600°C, although in other embodiments of the invention, medium temperatures in the range between 120 and 140°C are also selected. Selecting low temperatures allows for gentle drying of the boards. This prevents the formation of gypsum anhydrite in the boards.

[0033] When the panels are dried in the first stage A in these temperature ranges, the warm air absorbs a lot of moisture. The temperature and circulation speed of the air are preferably selected so that the dew point of the warm air is in the range between 60 and 99°C.

[0034] The drying zones of the first stage A have either cross-ventilation, for example without nozzle boxes, or longitudinal ventilation takes place. In a preferred embodiment, stage A is at least partially heated indirectly via a heat pump, for example to 50%. Ventilation in the first stage takes place in particular by recirculated air per zone. The first stage is preferably designed as a lightweight construction, whereby the individual drying zones have side walls and an upper cover, but do not require their own floor because they are built directly on the screed of a factory hall. The drying zones of the first stage preferably do not have nozzle boxes, thereby realizing a very simple and cost-effective construction. The first drying zones of the first stage, for example the first five drying zones of the first stages, are preferably equipped to absorb the heat from the at least one heat pump and / or with heating registers.Preferably, all drying zones of the first stage, or at least the first drying zones, are each equipped with a fan for generating a transverse air flow, while the warm air generated by the high-temperature heat pump is passed longitudinally through the first stage and preferably also through the second stage. The drying device is preferably equipped at several points with fans or nozzles and chimneys for discharging moisture-saturated air.

[0035] The exhaust air from the drying process of the first stage A can advantageously be reused by passing it into a heat exchanger to preheat the drying air of the second stage B.

[0036] An even higher efficiency of the drying process according to the invention can be achieved if the panels are first dried in a pre-drying stage prior to the first stage A, then in the first stage A and finally in the second stage B.

[0037] Preferably, the panels in stages A and B are conveyed through sections by means of separate conveyors for each stage A and B and / or each section. Alternatively, the conveyors are each driven by direct-drive motors, or they are at least partially interconnected using gears.

[0038] The invention provides a dryer for drying boards in a first and a second stage A, B, each of which is equipped with a conveyor device for conveying the boards arranged in tiers through the dryer, wherein the first stage (A) has at least one zone, wherein the first stage A has a supply device, a discharge device and a recirculation duct with conveying means and a heating device for recirculation air, as well as means for supplying supply air and means for discharging exhaust air, and wherein the second stage B is equipped to take over the boards from the first stage A and is equipped with a supply device for drying air and a discharge device for drying air and a heating device.

[0039] It is also an object of the invention to provide a system for carrying out a coupled method as explained above.

[0040] According to the invention, this object is achieved in that the plant comprises at least a first device for producing a binder using thermal energy and a second device for drying panels produced using a building material or insulating material or binder, wherein thermal energy can be transferred from the first device to the second device by means of a heat pump.

[0041] Advantageous further developments of the system arise from the subclaims.

[0042] Preferably, the first device is a calciner for burning gypsum or cement, the second device being used for drying panels manufactured using a building material or insulating material or binder, the first plant being connected to the second plant via at least one heat pump.

[0043] It is also advantageous if the calciner is a rotary kiln for drying gypsum and the second device is a plate dryer for drying gypsum boards.

[0044] Preferably, the plate dryer is provided with drying zones for drying the plates in a first (A) and a second stage (B), wherein the first stage (A) has at least one drying zone, wherein the first stage is heatable in recirculation mode and wherein the second stage (B) is equipped for receiving the plates from the first stage (A) and a device for fresh air ventilation.

[0045] In a further advantageous embodiment of the invention, it is provided that the first stage has a plurality of drying zones which can be heated by the heat pump or additionally by at least one heat exchanger or by warm air generated by at least one heater, by means of a heat pump, by means of a wet separator, or by means of superheated steam or by means of thermal oil or electrically indirectly or by means of low-calorific heat.

[0046] In another embodiment, it is advantageously provided that at most a single heat pump is provided for recovering heat, which can be supplied to the plates in the second stage.

[0047] In each of the two stages, the panels are dried at a speed and temperature that ensures rapid throughput of the panels through the dryer while simultaneously utilizing energy efficiently.

[0048] This optimizes the use of both primary and secondary energy. In particular, the primary energy used is maintained by utilizing waste heat and the condensation heat of the exhaust air, without increasing the demand for secondary energy by recirculating large air mass flows.

[0049] In particular, high flow rates for air circulation are avoided in the second stage, so that this dryer has only a low consumption of secondary energy.

[0050] Preferably, the dryer housing is equipped with a door for each drying zone. Preferably, the dryer, particularly in stage B, does not have its own floor, but is installed on the screed of a factory hall. Advantageously, a dryer is provided in which the first and second stages A, B each comprise at least one section and are equipped with means for circulating air perpendicular to the conveying direction of the panels.

[0051] For structural reasons, in another advantageous embodiment, the first stage A of the dryer is divided into several sections, which are at least partially equipped with nozzle boxes for cross ventilation by means of impingement flow of hot air.

[0052] Advantageously, the second stage B of the dryer is equipped with means for the flow of circulating air against and / or in the conveying direction of the plates.

[0053] In a further advantageous embodiment of the dryer, the second stage B is equipped with guide means for helically guiding the recirculating air or with at least one exhaust air fan in conjunction with at least one recirculating air fan. Alternatively, guide means, for example in the form of baffles, are provided.

[0054] Preferably, the drying device comprises at least one heat exchanger.

[0055] Roller conveyors or conveyor belts are preferably provided as conveying devices for transporting the panels to be dried in the dryer.

[0056] In stage B, the exhaust air from stage A, which is highly vapor-laden and passes through the heat exchanger, is cooled so much in the heat exchanger that some of the water vapor condenses. The resulting heated fresh air is fed to stage B.

[0057] When the drying air is directed countercurrently to the exhaust air passing through the heat exchanger in stage A, cooler drying air encounters already cooled exhaust air. This ensures the greatest possible condensation of the water vapor contained in the exhaust air and further improves the utilization of primary energy. The more intensive use of primary energy leads to significant savings in primary energy through the utilization of the condensation heat.

[0058] Overall, drying performance in stage B is at most half of that of stage A.

[0059] Each stage A, B is provided with a conveyor device for conveying boards arranged in tiers through the dryer. The dryer can be designed as a roller conveyor dryer or a belt dryer, with the conveyor device comprising several roller conveyors or conveyor belts arranged one above the other. The tiers are spaced apart, particularly in the rear section, by 100 mm to 200 mm, preferably 120 mm. Stages A, B preferably have the same number of tiers to accommodate the boards to be dried; a high number of tiers is desired, for example, at least twenty; however, it is understood that the number of tiers can be even higher. By having a high number of tiers and a short distance between the tiers, a very compact and therefore cost-effective dryer design is achieved.Since the number of floors in the two levels A and B is preferably identical, it is not necessary to provide a separate transfer area between the floors.

[0060] The plate dryer according to the invention can be constructed in a compact manner; it is not necessary to provide a base plate for the dryer; rather, it is sufficient if the side walls of the dryer are placed directly on the floor of a factory hall without the need to lay an additional base plate for the dryer.

[0061] For additional transient loads, additional heating devices can be installed in stage B.

[0062] The invention is explained in more detail below using an exemplary embodiment. Figure 1 shows the overall structure of the coupled arrangement with a first device designed as a rotary kiln and a second device designed as a drying device for drying building boards.

[0063] Fig. 2 the first device in detail,

[0064] Fig. 3 the second device in detail and

[0065] Fig. 4 shows a flow chart for the production of plasterboard.

[0066] A dryer 1 (Fig. 1 ) is supplied with heat energy from a calciner 101 with a rotary kiln 100 via a high-temperature heat pump 101.

[0067] The rotary kiln 100 (Fig. 2) comprises a rotary tube 102, which is rotated by a drive gear 104 driven by a motor 103. A burner 105 generates hot air, which is introduced into the interior of the rotary tube 102 through a line 106a and a chamber 106 upstream of the rotary tube 102. There, the hot air heats and dehumidifies the gypsum or another binding agent such as cement or a building material, which is introduced into the rotary tube 102 in powder form via a rotary valve 107 serving as the raw gypsum feeder. The rotary tube 102 is provided with outlets or inlets 108, 110, arranged, for example, via rotary unions, through which hot air or flue gas is discharged or cooling air is supplied. In particular, the flue gas escapes via the chamber 106, a flue gas exhaust fan 106b and a chimney 106c arranged downstream thereof.Cooling air is supplied via inlet 110; the cooling air, after being heated in the rotary tube 102, is fed back to the burner 105 as combustion air via outlet 108 and a fan 113, and then via a fan 113b. Air is fed to a chimney 113a via an outlet 111 located in the chamber 106 and a fan 112.

[0068] The fired stucco is removed from the rotary kiln 102 either directly via the outlet 109, a rotary valve 115 downstream of the rotary kiln, and a conveyor screw 115a, or via a cooling device downstream of the rotary kiln 102, or via a dust filter 114 and another rotary valve 116. Along with the building material, a significant portion of the hot air is also removed from the rotary kiln in this way, particularly via dust removal fans 117, 118. The fan 118 is downstream of a filter 119. The hot exhaust air is then fed by a heat pump 120. From the filter 119, the stucco is fed to the conveyor screw 115a via a rotary valve 119a.

[0069] The heat energy is extracted from the warm exhaust air passed through the fan 118 by the heat pump 120 using a coolant. The cooled exhaust air is then discharged through a chimney 120a.

[0070] From the heat pump 120, the heat energy is supplied via a coolant and / or a steam turbine via a heating register or a heat pump to a heat exchanger 121 and from there to the dryer 1.

[0071] For this purpose, a line 120b leads a fluid, for example water, from the heat pump to a heat exchanger 121. The heat exchanger 121 is connected to a coolant circuit with a line 122 and a compressor, for example a piston compressor 122a, for compressing a fluid serving as a coolant in the coolant circuit. Via the line 122, the coolant is fed to a heat exchanger 125, which serves as the steam generator for generating the steam that heats the plates in the dryer 1. The dryer 1 is thus connected to a steam circuit with vapor recompression. While the coolant circuit with the compressor forms a first heat pump stage, the steam circuit represents the second heat pump stage.

[0072] A compressor 127 is arranged in a line 126, through which the steam is fed as a heat transfer medium to the dryer 1. A condensate drain or condensate separator 129 is arranged in a line 128, through which the cooled steam is returned to the heat exchanger 125. Cooled warm air is returned from the dryer 1 via line 128 to the heat exchanger 125. A control valve 126a is also arranged in the line 126. The dryer 1 (Fig. 3) comprises two stages A and B for drying panels, which are fed to the dryer 1 in the direction of an arrow C. These panels are, in particular, building material panels, for example, plasterboard or

[0073] Gypsum fiberboard.

[0074] Each of the two stages A and B is preferably divided into sections 2. This applies in particular to section A, in whose sections 2 additional heat exchangers 12 are arranged, each connected to the lines 126 and 128, and which serve for heating with steam; alternatively, the use of a coolant from the heat pump is also possible. As additional means for generating heat in sections 2 of stage A, burners 12a are provided in all or some of the sections 2 of stage A, which can be used redundantly. This generates a temperature of up to 160 °C within sections 2 of stage A.

[0075] Preferably, stage A has a pre-drying section 3 on the inlet side. Pre-drying stage 3 is supplied with fresh air heated by a heat exchanger 4 via a supply line 6 equipped with a closable flap 5. This fresh air supply serves not only to heat the panels but also to seal stage A against other air currents and the penetration of outside air into stage A.

[0076] Fresh air heated by the heat exchanger, wet steam, or a coolant is distributed via a line 7 branching off from the supply line 6 into individual lines 9, 10, 11. From these, the fresh air is directed to heating devices 12, 13, or 14, respectively, which are arranged, for example, in a ceiling box above the nozzle boxes. As shown in Fig. 1, the heating devices or heating registers 12 to 14 are each assigned to two sections 2 of stage A. It is understood that other assignments may be made in another embodiment. For example, in another embodiment, one heating device is provided for each section. The heating devices 12 to 14 are preferably direct heating devices such as burners, or indirect heating devices such as steam or electric heaters.Within sections 2 or jointly for each section, at least one recirculation fan 15 to 18 is provided to generate a cross-flow of the heated air in sections 2 as recirculation air. Alternatively, two recirculation fans 15 to 17 are arranged in each section 2.

[0077] Stage B is also supplied with heated fresh air from heat exchanger 4. Lines 19 to 24 serve this purpose. Of these, lines 19, 21, and 23 are each equipped with a control damper 25, 26, and 27, respectively.

[0078] At the inlet of sections 2, the air flowing into sections 2 from lines 19 to 24 is heated by heating devices 29 to 31. The heating devices 29 to 31 are switched on when additional heating energy is required; this is the case when the system is started up, when insufficient heat is yet available from stage A and heat exchanger 4 is not yet receiving any warm exhaust air or not enough warm exhaust air from stage A. The heating devices are also required when the system is shut down and insufficient warm air is no longer available from stage A to enter stage B. The heating devices 29 to 31 can also be used if the boards to be dried have a higher moisture content than expected, or when changing between different board formats, which can lead to a lack of heat energy in stage B.Thus, the heating devices 29 to 31 are kept in reserve especially for transient loads in stage B.

[0079] It is understood that, depending on the length of stage B, a plurality of lines can be provided for supplying air, in particular warm air from the heat exchanger 4 or from another heat exchanger, in order to recover the evaporation enthalpy of the water evaporated from the plates.

[0080] Just like the recirculation fans, exhaust fans 32, 33 are also arranged along the entire length of stage B, of which only the exhaust fans 32, 33 are shown as examples. Moist air is removed from stage B via these and chimneys 34, 35. Additionally, an exhaust fan 36 is provided at the end in conjunction with a chimney 37.

[0081] An internal heat exchanger can be provided in both stage A and stage B, for example above the nozzle boxes in stage A in a ceiling box or above the conveyor device in stage B, also in a ceiling box provided for this purpose.

[0082] The heat exchanger 4 is connected to sections 2 of stage A via exhaust air ducts 38 and a central exhaust air duct 39. Warm, moisture-saturated air is conveyed via the exhaust air ducts 38, 39 via an exhaust air fan 40 to the heat exchanger 4, where it condenses and releases its moisture to the environment as water via a chimney 42.

[0083] The heat exchanger 4 draws in fresh air via a fresh air fan 41. A heating register 43 is provided between the fresh air fan 41 and the heat exchanger to utilize the condensate heat.

[0084] The coupled method according to the invention is used for the production of gypsum plasterboard, wherein raw gypsum 400 (Fig. 4) is fed to a calciner 101. The calciner 101 produces stucco 401 in the rotary kiln 100, which is fed to a device 402 for producing gypsum plasterboard. The device 402 comprises a mixer; with the aid of cardboard 403, starch 404, and additives 405, gypsum plasterboards 406 are produced in the mixer using setting tape and a cutting device. The gypsum plasterboards 406 are then fed to the dryer 1.

[0085] On the other hand, waste heat 407 from the calciner 101 is fed to a heat pump 408 or a plurality of heat pumps or heat recovery devices. The at least one heat pump 408 supplies heating energy 409 for the dryer 1, which produces dry plasterboards 410. These then undergo the steps 412 of trimming, stacking, and packaging until they become ready-to-sell plasterboards 411.

Claims

Patent claims 1. Coupled method, comprising a method for producing or treating a binder using thermal energy in a first device (100) and a method for drying boards produced using a building material or insulation material or binder in a second device designed as a drying device (1), wherein waste heat generated in the first device is recovered via at least one heat pump and is at least partially fed to the second device in which it is used to dry the boards.

2. Coupled method according to claim 1, characterized in that heat is conducted from the heat pump to the second device (1) via at least one heat exchanger.

3. Coupled method according to claim 1 or 2, characterized in that in the rotary kiln (100) warm air heats the building material and the air surrounding the building material in the rotary kiln in a countercurrent process and that the heated building material is carried out of the rotary kiln (100) together with the air heated in the rotary kiln, that the building material is led out of the rotary kiln (100) via conveying means and that the heated air is fed to the at least one heat pump (120).

4. Coupled process according to one of claims 1 to 3, characterized in that gypsum or cement clinker is burned in the calciner and that boards containing gypsum or cement clinker are dried in the second device.

5. Coupled process according to claim 4, characterized in that gypsum boards or cement boards are produced in an intermediate process from the gypsum heated in the rotary kiln or cement clinker heated in the calciner, and in that the gypsum boards or cement boards are dried in the second device. A coupled method according to one of claims 1 to 5, characterized in that heated air from the heat pump is introduced into the second device designed as a drying device. A coupled method according to claim 5, characterized in that the heated air is supplied to at least one front part of the second device, relative to the plate conveying direction. A coupled method according to claim 6 or 7, characterized in that the plates in the drying device pass through a first stage (A) and a second stage (B), wherein the two stages (A, B) each have tiers and the plates are each placed on surfaces formed in tiers and are guided through the drying device in the respective tiers of the two stages (A, B).wherein the panels are brought into contact with high-temperature drying air in the first stage (A) and dried, and are dried with lower-temperature drying air in the second stage (B), wherein the panels are heated at least in the first stage by warm air generated by a heat exchanger, by means of a heat pump, by means of a wet separator, by a burner directly or by means of superheated steam or by means of thermal oil or indirectly electrically or by means of low-calorific heat, wherein at most a single means is provided for recovering heat, which is supplied to the panels in the second stage. A coupled process according to one of claims 1 to 8, characterized in that the panels are dried by circulating air at least in the first stage. A coupled process according to one of claims 1 to 9, characterized in thatthat the plates are dried at least in the region of the first stage (A) at least substantially by the use of nozzle boxes.

1. Coupled process according to one of claims 1 to 10, characterized in that the panels are dried in the first stage (A) or in the second stage (B) by at least one internal heat exchanger (27) and / or by at least one external heat exchanger (4, 43, 44, 45).

2. Coupled process according to one of claims 1 to 11, characterized in that the panels are dried in the second stage (B) by drying air at a temperature of 20 to 90 °C.

3. Coupled process according to one of claims 1 to 12, characterized in that the exhaust air from the first stage (A) is passed into a heat exchanger (31) for preheating the drying air from the second stage (B).

4. A coupled process according to one of claims 1 to 13, characterized in that the panels are first dried in a pre-drying stage preceding the first stage (A), then in the first stage (A), and finally in the second stage (B).Plant for carrying out a coupled process according to one of claims 1 to 14, characterized in that the plant comprises at least a first device for producing binder using thermal energy and a second device for drying panels manufactured using a building material, insulation material or binder, wherein thermal energy can be transferred from the first device to the second device by means of a heat pump.

6. Plant according to claim 15, characterized in that the first device is a calciner for drying gypsum or cement and that the second device is used for firing panels manufactured using a building material, insulation material or binder, wherein the first plant is connected to the second plant via at least one heat pump. Plant according to claim 16, characterized in that the calciner is a rotary kiln for drying gypsum, and the second device is a plate dryer for drying gypsum boards. Plant according to one of claims 15 to 17, characterized in that the plate dryer is provided with drying zones for drying the boards in a first stage (A) and a second stage (B), wherein the first stage (A) has at least one drying zone, wherein the first stage is heatable in recirculation mode, and wherein the second stage (B) is equipped for receiving the boards from the first stage (A) and a device for longitudinal ventilation.System according to one of claims 15 to 18, characterized in that the first stage comprises a plurality of drying zones that can be heated by the heat pump, at least one heat exchanger, or by warm air generated by at least one heater, by a heat pump, by a wet separator, by superheated steam, by thermal oil, indirectly electrically, or by low-calorific heat. System according to claim 19, characterized in that at most a single means for recovering heat is provided, which can be supplied to the plates in the second stage.

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