Method and separating device for separating water from a carbohydrate / water mixture

Abstract

The invention relates to a method for separating water from a carbohydrate / water mixture (4), wherein - the carbohydrate / water mixture (4) is introduced into at least one separating unit (3) in which water is separated from the carbohydrate / water mixture (4), - the at least one separating unit (3) is supplied with useful heat on a high-temperature side (9) in order to thermally separate the water from the carbohydrate / water mixture (4), - secondary thermal energy is discharged from the at least one separating unit (3) on a low-temperature side (13), - heat to be recycled is removed from the secondary thermal energy on the low-temperature side (13), and - the heat to be recycled is supplied to the high-temperature side (9) at a temperature level of more than 100 °C at least as part of the useful heat by means of a compression heat pump (17) which has a closed working media circuit (19).

Description

[0001] DESCRIPTION

[0002] Method and separation device for separating water from a

[0003] Carbohydrate-water mixture

[0004] The invention relates to a method and a separation device for separating water from a carbohydrate-water mixture.

[0005] To separate water from a water-containing mixture, such a mixture is introduced into at least one separation unit, wherein useful heat is supplied to the separation unit on a high-temperature side, by means of which the water is thermally separated. The at least one separation unit also has a low-temperature side on which thermal secondary energy is dissipated. To make the process efficient, recycled heat can be extracted from the thermal secondary energy and fed back into the high-temperature side at least as part of the useful heat. To increase the temperature level of the recycled heat, a heat pump can be provided. If an adsorption heat pump or an absorption heat pump is used, this disadvantageously leads to a limitation of the available temperature range and / or entails problems with regard to the efficiency and controllability of the process.If a vaporous medium exiting the low-temperature side of a separation unit is compressed and directly returned to a high-temperature side of the same or another separation unit, for example, in the form of vapor compression, this adversely leads to the mixing of different material streams, in particular the mixing of different condensate qualities or even the mixing of a heating medium with the product. Furthermore, this design poses the risk of droplets entering a compressor impeller intended for compressing the medium, which represents a significant operational risk for the compressor.If the recycled heat is to be recycled via a number of discrete separation stages, this design also requires a multi-stage arrangement of serially connected compressors, which increases the risk of failure of the entire separation system, as the recycling of recycled heat is no longer guaranteed if even a single compressor in the multi-stage arrangement fails. Furthermore, the size of the compressors depends on the specific volume of the medium to be compressed, which leads to design problems, especially in the vacuum range.

[0006] The invention is therefore based on the object of creating a method and a separation device for separating water from a carbohydrate-water mixture, wherein the aforementioned disadvantages do not occur.

[0007] The object is achieved by providing the present technical teaching, in particular the teaching of the independent claims as well as the embodiments disclosed in the dependent claims and the description.

[0008] The object is achieved in particular by providing a method for separating water from a carbohydrate-water mixture, wherein the carbohydrate-water mixture is introduced into at least one separation unit in which water is separated from the carbohydrate-water mixture, wherein useful heat is supplied to the at least one separation unit on a high-temperature side in order to thermally separate the water from the carbohydrate-water mixture, wherein thermal secondary energy is removed from the at least one separation unit on a low-temperature side, wherein recycling heat is extracted from the thermal secondary energy on the low-temperature side, and wherein the recycling heat is fed back to the high-temperature side at a temperature level of greater than 100 °C, at least as part of the useful heat, by means of a compression heat pump having a closed working medium circuit.By using a compression heat pump with a closed working fluid circuit, the recycled heat is advantageously returned from the low-temperature side to the high-temperature side without simultaneously recirculating a material flow. Rather, the high-temperature side is connected to the low-temperature side purely thermally, i.e., thermally, through a heat flow, but remains materially separated from the low-temperature side with regard to the return of recycled heat. This advantageously prevents mixing of different material flows, in particular mixing of different condensate qualities or even a heating medium with the product.The risk of droplets entering a compressor impeller is completely eliminated, and the returned heat flow can be easily influenced by the amount of working fluid circulated in the compression heat pump. Serial connection of multiple compressors is not required, particularly in the case of multi-stage recirculation of the recycled heat. Thus, the operational risk of a separation device operated with the method proposed here is low. Furthermore, the use of a compression heat pump with a closed working fluid circuit advantageously allows a comparatively high temperature level of more than 100 °C on the high-temperature side. Such a compression heat pump also exhibits high efficiency, particularly at temperatures above 100 °C, compared to an adsorption or absorption heat pump.In addition, such a compression heat pump has very good controllability, particularly in partial load operation, by varying the compressor speed.

[0009] In the context of the present technical teaching, a compression heat pump having a closed working medium circuit is understood in particular to mean a thermal device that carries out a thermal cycle, also referred to as a counterclockwise cycle. In particular, the compression heat pump has—in particular in the specified order along a flow direction of the working medium in the closed working medium circuit—an expansion valve or a throttle for expanding the working medium, a first working medium heat exchanger, in particular a working medium evaporator, at least one working medium compressor, and a second working medium heat exchanger, in particular a working medium condenser. The compression heat pump is in particular a high-temperature heat pump or an ultra-high-temperature heat pump.The working medium circuit has as working medium in particular a refrigerant, in particular a hydrofluoroolefin or a hydrochlorofluoroolefin, in particular (Z)-1,3,3,3-tetrafluoropropene, (E)-1,3,3,3-tetrafluoropropene, 1,1,2,2,3-pentafluoropropane, (Z)-l-chloro-3,3,3-trifluoropropene, (E)-l-chloro-3,3,3-trifluoropropene, (Z)-l-chloro-2,3,3,3-tetrafluoropropene, (E)-l-chloro-2,3,3,3-tetrafluoropropene, (Z)-l,l,l,4,4,4-hexafluoro-2-butene, 1,1,1,3,3-pentafluorobutane, dodecafluoro-2-methylpentan-3-one, isobutane, butane, or n-Pentane. The working medium compressor is, in particular, a mechanical compressor, especially a reciprocating piston compressor, screw compressor, or turbo compressor.The amount of working medium circulated in the working medium circuit per unit of time, and thus the returned heat flow, can be adjusted, in particular, by appropriately controlling the working medium compressor, in particular by varying the speed of the working medium compressor. In the context of the present technical teaching, the fact that the recycle heat is fed back to the high-temperature side at a temperature level greater than 100 °C means, in particular, that the condensation temperature of the working medium during operation of the compression heat pump is greater than 100 °C.

[0010] In particular, the useful heat is supplied to the high-temperature side as primary thermal energy.

[0011] In one embodiment of the method, the useful heat is supplied to the high-temperature side—in particular directly—by means of a heating medium, in particular by means of heating steam. In particular, the separation unit has at least one heating surface, preferably a plurality of heating surfaces, which is exposed to the heating medium on one heating medium side and is in thermal contact, in particular in contact with the carbohydrate-water mixture, on a product side facing away from the heating medium side.

[0012] In one embodiment of the process, it is alternatively or additionally provided that the useful heat is supplied to the high-temperature side by superheating the carbohydrate-water mixture. In particular, in this case, the separation unit has an evaporation chamber in which a - in particular sudden or instantaneous - evaporation of water from the superheated carbohydrate-water mixture can take place, in particular in the form of the formation of flash steam. The superheating of the carbohydrate-water mixture takes place in particular upstream of the evaporation chamber, i.e., before the carbohydrate-water mixture enters the evaporation chamber. In particular, the pressure in the evaporation chamber is lower than the pressure prevailing upstream of the evaporation chamber at the point where the carbohydrate-water mixture is superheated.

[0013] The term "upstream of a first element" generally means here and below that a second element, so designated, is located upstream of the first element along a flow or stream direction, i.e., is reached first—before the first element—by a test element moving along the flow or stream direction. Accordingly, the term "downstream of a first element" means that a second element, so designated, is located downstream of the first element along a flow or stream direction, i.e., is reached later—after the first element—by the test element.

[0014] In the context of the present technical teaching, a separation unit is understood to mean, in particular, a device - also referred to as an evaporation or crystallization stage - which is designed in such a way that water can be separated from a carbohydrate-water mixture with the device, in particular in the device.

[0015] According to one embodiment, the separation unit has at least one heating surface, preferably a plurality of heating surfaces, wherein the at least one heating surface is configured to be exposed to the heating medium on a heating medium side of the at least one heating surface and to be brought into thermal contact, in particular into contacting contact, with the carbohydrate-water mixture on a product side of the at least one heating surface facing away from the heating medium side. Such a separation unit can be designed, in particular, as a falling-film evaporator.

[0016] Alternatively or additionally, according to one embodiment, the separation unit comprises an evaporation chamber arranged and configured such that evaporation of water from the superheated carbohydrate-water mixture, particularly in the form of flash steam formation, can occur in the evaporation chamber. In one embodiment of the separation unit, a superheating device is provided upstream of the evaporation chamber, which is configured to superheat the carbohydrate-water mixture before it enters the evaporation chamber.

[0017] In the context of the present technical teaching, a separation device comprises, in particular, at least one such separation unit, in particular a plurality of such separation units. The separation units are arranged one behind the other in terms of flow, i.e., in particular, arranged serially or connected in series, with respect to a heat flow on the one hand and a product flow of the carbohydrate-water mixture on the other. In one embodiment, it is provided that the sequence of the separation units with respect to the heat flow on the one hand and with respect to the product flow on the other hand is the same. However, in another embodiment, it is also possible for the sequence of the separation units with respect to the heat flow to differ from the sequence of the separation units with respect to the product flow.In particular, it is possible for the order of the product flow to be opposite to the order of the heat flow. However, according to yet another embodiment, it is also possible for there to be at least no simple relationship between the order of the heat flow, on the one hand, and the order of the product flow, on the other.

[0018] In one embodiment, the separation device comprises only separation units, each with at least one heating surface. In another embodiment, the separation device comprises only separation units, each with an evaporation chamber. In yet another embodiment, the separation device comprises at least one separation unit with at least one heating surface and at least one further separation unit with an evaporation chamber.

[0019] In the context of the present technical teaching, the separation of water from a carbohydrate-water mixture is understood in particular to mean that water is removed or expelled from the carbohydrate-water mixture, whereby a water content of the carbohydrate-water mixture is reduced and a carbohydrate content of the carbohydrate-water mixture is increased. In particular, a product stream of the carbohydrate-water mixture is divided into a first partial product stream comprising a concentrated carbohydrate-water mixture with an increased carbohydrate content, and a second partial product stream comprising only water or a diluted carbohydrate-water mixture with an increased water content.Alternatively or additionally, a product stream of the carbohydrate-water mixture is divided into a first partial product stream containing crystallized carbohydrate and a second partial product stream containing only water or a diluted carbohydrate-water mixture with an increased water content. Separation is thus understood to mean, in particular, concentration by evaporation or crystallization.

[0020] In the context of the present technical teaching, thermal separation is understood in particular to mean separation by the addition of heat, wherein the water is removed from the carbohydrate-water mixture due to the added heat. In particular, in one embodiment, the water is separated from the carbohydrate-water mixture by expelling the water—in particular by evaporation, in the form of steam—and / or by crystallizing a carbohydrate from the carbohydrate-water mixture. The resulting partial product stream, which consists at least substantially of water—optionally with entrained carbohydrate portions—is also referred to as vapor. In a broader sense, vapor, in particular vapor generated from a condensate, or also alcohol-containing vapor, is sometimes referred to as vapor. In ethanol production in particular, the essential component of the vapor is alcohol.

[0021] In the context of the present technical teaching, useful heat is understood to mean heat or synonymously thermal energy which is supplied to the at least one separation unit - in particular as thermal primary energy - in order to thermally separate the water from the carbohydrate-water mixture.

[0022] In the context of the present technical teaching, thermal secondary energy is understood to mean, in particular, heat or, synonymously, thermal energy, which is removed on the low-temperature side by the at least one separation unit. In particular, the thermal secondary energy is removed embodied in the separated water, in particular in the form of water vapor, in particular in the form of vapor. However, thermal secondary energy can also be removed in the form of a condensate, wherein in particular the recycling heat can also be extracted from a condensate of a separation unit, in particular a condensate of a vapor or a condensate of a heating medium. It is possible for the recycling heat to be extracted directly from the condensate. However, it is also possible for the condensate to first be fed to another heat sink and the recycling heat to then be extracted from the remaining residual heat of the condensate.

[0023] In the context of the present technical teaching, recycled heat refers in particular to that portion of the thermal secondary energy that is extracted from the low-temperature side and returned to the high-temperature side by means of the compression heat pump. In particular, the compression heat pump generates additional heat, referred to as heat pump heat, with the recycled heat being fed back into the system, at least as part of the useful heat, in addition to the heat pump heat from the high-temperature side.

[0024] In certain embodiments, the recycle heat increased by the heat pump heat is sufficient, at least during ongoing operation, to separate the water from the carbohydrate-water mixture. In these cases, the useful heat consists of the recycle heat increased by the heat pump heat. In other embodiments, or for starting up a separation device, the useful heat includes, in addition to the recycle heat increased by the heat pump heat, heat provided elsewhere, which is also referred to as additional heat. In these cases, the additional heat is always supplied exclusively on the high-temperature side of the at least one separation unit in special embodiments; in particular, it is added - on the hot side of the working fluid circuit - to the recycle heat increased by the heat pump heat.In particular, no additional heat is introduced into the first working medium heat exchanger, i.e., in particular, no additional heat is fed into the cold side of the working medium circuit. It is energetically advantageous to introduce additional heat exclusively on the high-temperature side or the hot side of the working medium circuit, since this avoids increased evaporation of the working medium in the first working medium heat exchanger, which would otherwise be highly detrimental to energy efficiency, and thus simultaneously avoids an increase in the electrical and / or mechanical energy requirement for compressing the working medium. Such a design would be particularly disadvantageous in connection with the material separation of a heating mass flow on the one hand and the working medium circuit on the other, as discussed below.

[0025] In particular, the recycling heat consists solely of thermal secondary energy generated during the thermal separation of water from the carbohydrate-water mixture. In particular, the recycling heat consists of a quantity of heat extracted from a waste stream of the at least one separation unit, in particular from a mixture of waste streams from several separation units connected in parallel thermally and / or in series along a heat stream. The recycling heat is particularly different from optionally additional externally supplied heat quantities that do not originate as thermal secondary energy generated during the separation of water from the carbohydrate-water mixture.In particular, such external heat quantities can be embodied by steam from a boiler house, or they can be in the form of electrical energy, in particular from the public grid and / or from in-house production, in particular from an in-house combined heat and power plant. Advantageously, the manner described here makes it possible to provide a separation device with the lowest possible drive energy requirement for the compression heat pump, and to keep the circulating volume flow in the working fluid circuit and the associated dimensioning of the components of the working fluid circuit low.

[0026] According to a further development of the invention, the carbohydrate-water mixture is selected from a group consisting of: a sucrose-containing medium, in particular a sucrose-containing solution or a sucrose-containing suspension, in particular thin juice or thick juice for sucrose production, sucrose syrup, an isomaltulose-containing medium, in particular an isomaltulose-containing solution or an isomaltulose-containing suspension, a stillage from bio-alcohol production, an alcohol-water solution, in particular a bio-alcohol-water solution, a sugar alcohol-water medium, in particular a sugar alcohol-water solution or a sugar alcohol-water suspension, a starch-containing medium, in particular a starch-containing solution or a starch-containing suspension, and moisture-containing field crop pieces, in particular sugar beet pulp or chicory roots.

[0027] In the following, a thin juice is generally understood to be a carbohydrate-water mixture with a lower dry matter content, and a thick juice is understood to be a corresponding carbohydrate-water mixture with a higher dry matter content. The dry matter content of the thick juice is higher than the dry matter content of the thin juice, and vice versa. Specifically, i.e., where explicitly stated or clear from the context, a thin juice is understood to be a sucrose solution with a lower dry matter content, and a thick juice is understood to be a sucrose solution with a higher dry matter content.

[0028] In particular, within the scope of the process, a thin juice, in particular with a dry matter content of 10% to 25%, is preferably concentrated to a thick juice with a dry matter content of 65% to 80%. Alternatively or additionally, within the scope of the process, a desired supersaturation is set or achieved in a crystallization process by separating off water. In particular, within the scope of the process, a sugar is crystallized from a sugar solution. In particular, in one embodiment, sucrose is crystallized from an aqueous sucrose solution, in particular a thick juice. In another embodiment, isomaltulose is crystallized from an aqueous isomaltulose solution, in particular a thick juice. Alternatively or additionally, within the scope of the process, a rectification process is carried out by separating off water.Alternatively or additionally, sugar beet pulp and / or products from bioethanol production are dried in a dry matter range of 30% to 95% within the process.

[0029] According to a further development of the invention, a plurality of separation units are used to separate the water from the carbohydrate-water mixture. The separation units are thermally connected to one another and arranged in series along a heat flow, wherein the recycled heat of the thermal secondary energy is extracted from the low-temperature side of a downstream separation unit of the plurality of separation units and supplied to the high-temperature side of an upstream separation unit of the plurality of separation units by means of the compression heat pump. The upstream separation unit is arranged upstream of the downstream separation unit along the heat flow. Accordingly, the downstream separation unit is arranged downstream of the upstream separation unit along the heat flow.

[0030] In particular, the separation units are arranged in series along a temperature gradient and thermally connected to one another. The term "upstream of a first element" means that a second element, so designated, is arranged along the temperature gradient at a higher temperature level than the first element. Accordingly, the term "downstream of a first element" means that a second element, so designated, is arranged along the temperature gradient at a lower temperature level than the first element.

[0031] In particular, the low-temperature side of each separation unit—except for the last separation unit in the series—is thermally connected to the high-temperature side of a separation unit immediately following along the heat flow. Correspondingly, the high-temperature side of each separation unit—except for the first separation unit in the series—is thermally connected to the low-temperature side of a separation unit immediately preceding along the heat flow. In one embodiment, at least one separation unit has at least two partial separation units that are arranged parallel to one another with respect to the heat flow, i.e., in particular, at the same temperature level. The at least two partial separation units are preferably arranged in series or serially with respect to the product flow, i.e., one behind the other.

[0032] In particular, the separation units are additionally arranged in series along a pressure gradient. In particular, the pressure gradient has the same sign as the temperature gradient. In particular, the pressure prevailing in the separation units decreases along the row of separation units in the same direction in which the temperature decreases in the separation units.

[0033] In one embodiment, the recycled heat is not returned to the same separation unit from whose thermal secondary energy it was extracted, but rather is returned counter to the heat flow through at least one separation unit, in particular a plurality of separation units. The compression heat pump advantageously raises the temperature level of the recycled heat—in particular by supplying heat from the heat pump—while simultaneously returning the recycled heat against the temperature gradient.

[0034] According to a further development of the invention, it is provided that the recycling heat of the thermal secondary energy is taken from a last separation unit of the plurality of separation units along the heat flow - in particular the last separation unit in the row of separation units along the temperature gradient, i.e. the separation unit with the lowest temperature level - and is supplied to the high-temperature side of a first separation unit of the plurality of separation units along the heat flow - in particular the first separation unit in the row of separation units along the temperature gradient, i.e. the separation unit with the highest temperature level.

[0035] According to a further development of the invention, the useful heat of the at least one separation unit is supplied via a heating medium. In particular, the useful heat of the at least one separation unit is supplied via steam, also referred to as heating steam, in particular water vapor, as the heating medium. It is possible for the useful heat of a separation unit to not include any recycled heat. Alternatively, the useful heat of a separation unit comprises, in addition to heat provided elsewhere, i.e., additional heat—for example, embodied by steam from a boiler house—the recycled heat, in particular augmented by the heat pump heat. Further alternatively, the useful heat consists of the recycled heat, in particular augmented by the heat pump heat; this means, in particular, that the useful heat exclusively comprises the sum of the recycled heat and the heat pump heat.In particular, the recycling heat - in particular increased by the heat pump heat - is supplied to the high-temperature side of the separation unit in the form of a vapor which is generated using the recycling heat from a condensate produced during separation from the heating medium - in particular from the same vapor - in the same separation unit.

[0036] Alternatively, it is provided that the useful heat is used to heat, in particular to superheat, the carbohydrate-water mixture upstream of an evaporation chamber of the at least one separation unit. In this embodiment, water evaporates from the heated, in particular superheated, carbohydrate-water mixture in the evaporation chamber, in particular upon entry into the evaporation chamber, which is also referred to as the formation of flash steam. In particular, the pressure in the evaporation chamber is lower than the pressure at the location where the carbohydrate-water mixture is heated upstream of the evaporation chamber. According to one embodiment, the carbohydrate-water mixture is heated, in particular superheated, upstream of the separation unit.In this case, a superheating device configured to heat, in particular superheat, the carbohydrate-water mixture upstream of the evaporation chamber is not itself part of the separation unit but rather is arranged upstream of the separation unit. According to this embodiment, the useful heat of the separation unit is thus supplied by the carbohydrate-water mixture heated, in particular superheated, upstream of the separation unit. According to another embodiment, the carbohydrate-water mixture is heated, in particular superheated, in the separation unit upstream of the evaporation chamber. In this case, the superheating device is part of the separation unit and is arranged in the separation unit upstream of the evaporation chamber.The useful heat is supplied to the carbohydrate-water mixture – either upstream of the separation unit or within the separation unit – in particular via a heat transport medium or heating medium, in particular water, steam, or a heat transfer oil. In particular, the useful heat consists of the recycled heat, in particular augmented by the heat pump heat. Alternatively, the useful heat of a separation unit may not include any recycled heat. Further alternatively, the useful heat of a separation unit may include the recycled heat, in particular augmented by the heat pump heat, in addition to heat provided elsewhere, i.e., additional heat – for example, embodied by steam from a boiler house.

[0037] According to a further development of the invention, the recycling heat is extracted from a waste stream carrying the water separated from the carbohydrate-water mixture. Thus, the heat removed from the waste stream on the low-temperature side of a separation unit is advantageously returned to the high-temperature side of the separation unit or another separation unit, making the process proposed here highly efficient. At the same time, the compression heat pump achieves a material separation of the low-temperature side from the high-temperature side, whereby not a portion of the waste stream itself is returned, but only the recycling heat extracted from the waste stream. Thus, with regard to the return of the recycling heat, the low-temperature side and the high-temperature side are only thermally connected to one another via a heat flow, but are materially separated from one another.

[0038] In the context of the present technical teaching, a waste stream is understood in particular to mean a mass stream that comprises at least the water separated from the carbohydrate-water mixture in the separation unit, optionally plus entrained components of the carbohydrate-water mixture. In particular, the waste stream is steam formed from the carbohydrate-water mixture in the separation unit, moist air, in particular hot air, or in particular vapor. However, the waste stream can also be a condensate.

[0039] In one embodiment, the waste stream is fed at least partially directly to the first working-medium heat exchanger—in particular, the working-medium evaporator—of the compression heat pump. In this way, the recycle heat can be extracted from the waste stream directly in the first working-medium heat exchanger.

[0040] In another embodiment, the recycled heat from the waste stream is supplied to the first working-medium heat exchanger—in particular, the working-medium evaporator—via a first heat transport device. This allows, in particular, a spatial separation between the waste stream and the first working-medium heat exchanger or even the compression heat pump as a whole.

[0041] If the recycling heat is extracted from a condensate which is not a mass flow, it is also possible in this case that the condensate is fed at least partially directly to the first working medium heat exchanger in a first embodiment, or that in a second embodiment the recycling heat extracted from the condensate is fed to the first working medium heat exchanger via a heat transport device.

[0042] In the context of the present technical teaching, a heat transport device is understood to mean a device that is configured to transport heat from a first location to a second location spaced apart from the first location. The heat transport device can, in particular, comprise at least one heat transport element, for example, in the simplest embodiment, a bar or rod made of a thermally conductive material. In a more complex embodiment, the heat transport device comprises, in particular, at least one heat pipe. Alternatively or additionally, the heat transport device comprises at least one pipeline and / or a fitting, in particular at least one heat distributor.Alternatively or additionally, the heat transport device comprises at least one heat transport medium circuit, in particular with a liquid heat transport medium, wherein, for example, water or a heat transfer oil can be provided as the heat transport medium. The heat transitions in the heat transport medium circuit can include phase transitions or be designed as sensible heat transitions, i.e., without phase transitions. Alternatively or additionally, the heat transport device comprises or consists of a flue gas heat exchanger.

[0043] According to a further development of the invention, it is provided that the recycling heat is supplied to a heating mass flow which is supplied to the at least one separation unit on the high-temperature side in order to thermally separate the water from the carbohydrate-water mixture.

[0044] In the context of the present technical teaching, a heating mass flow is understood to be a heat-carrying mass flow. The fact that the recycled heat is added to the heating mass flow means, in particular, that the thermal energy of the heating mass flow is increased by the recycled heat—in particular, by the heat pump heat.

[0045] In particular, the heating mass flow is different from the working medium of the compression heat pump, in particular, it is materially separated from it. In particular, the heating mass flow does not contain the working medium of the compression heat pump; in particular, the heating mass flow does not consist of the working medium of the compression heat pump. In particular, the heating mass flow is materially separated from the working medium of the compression heat pump and is instead only thermally connected to the working medium.

[0046] In one embodiment of the process, the heating mass flow is the mass flow of a heating medium used to heat the carbohydrate-water mixture. In particular, it is possible to use steam, in particular water vapor, or air, in particular hot air, or a heat transport medium as the heating medium. In another embodiment of the process, the heating mass flow is the mass flow of the carbohydrate-water mixture itself. In this case, the recycling heat is used in particular to heat or preheat, in particular to superheat, the carbohydrate-water mixture. In one embodiment, the carbohydrate-water mixture is subsequently introduced into an evaporation space of the separation unit, where water evaporates abruptly from the carbohydrate-water mixture—in particular as so-called flash steam.

[0047] In one embodiment, at least a partial heating mass flow of the heating mass flow is passed upstream of the separation unit through the second working medium heat exchanger—in particular, the working medium condenser—of the compression heat pump. In this way, the recycled heat can be supplied to the heating mass flow directly from the second working medium heat exchanger. In one embodiment, the entire heating mass flow is passed upstream of the separation unit through the second working medium heat exchanger; in particular, the carbohydrate-water mixture is passed directly through the second working medium heat exchanger.

[0048] In another embodiment, the recycled heat is supplied to the heating mass flow from the second working-medium heat exchanger—in particular, the working-medium condenser—via a second heat transport device. This allows, in particular, a spatial separation between the heating mass flow and the second working-medium heat exchanger or even the compression heat pump as a whole.

[0049] In one embodiment, an evaporation unit is used as the at least one separation unit. In another embodiment, a crystallization unit is used as the at least one separation unit.

[0050] According to a further development of the invention, it is provided that at least one evaporation unit - as at least one first separation unit - and at least one crystallization unit - as at least one second separation unit - are used as the at least one separation unit, wherein recycling heat is extracted from thermal secondary energy of the at least one evaporation unit and is fed back to the at least one evaporation unit by means of a first compression heat pump, and wherein recycling heat is extracted from thermal secondary energy of the at least one crystallization unit and is fed back to the at least one crystallization unit by means of a second compression heat pump.By using separate compression heat pumps for the at least one evaporation unit and thus a concentration or thickening process on the one hand, and for the at least one crystallization unit and thus a crystallization process on the other, it is advantageously possible to thermally optimize the various processes at least largely independently of one another, in particular by carrying them out at different temperature levels. In particular, thermally decoupling the concentration or thickening, in particular the production of thick juice from the carbohydrate-water mixture entering the process as thin juice, from the crystallization allows for particularly efficient process control of the concentration or thickening process, in particular because it is no longer necessary to ensure that a sufficient amount of heat remains for crystallization at the end of the process.Rather, the process can advantageously be managed in such a way that the initially introduced heat quantity is used as completely as possible in the process itself. In particular, the temperature level for evaporation can be lowered, especially - for a sucrose solution, for example - from the conventional 130 °C to 135 °C in the initial separation stage to approximately 120 °C, so that the thermal impact is reduced and thus the risk of discoloration of the resulting thick juice is lowered. By decoupling the crystallization, a sufficient amount of heat, particularly in the form of vapors, can be easily provided for use in the first compression heat pump. At the same time, the thermal decoupling of the various processes allows the temperature for crystallization to be increased, so that this too can be carried out under particularly favorable conditions.In particular, the (vapor) temperature for crystallization can be raised, in particular—for example, for sucrose crystallization—from the conventional approximately 60°C at 0.2 bar absolute to approximately 65°C at 0.25 bar absolute, whereby the crystallization rate can advantageously be increased, in particular to its maximum. In particular, a space / time yield in the sugar house can be increased. With regard to the overall process, the total amount of heating steam to be supplied from the boiler house can advantageously be significantly reduced. Furthermore, the heating steam temperature for crystallization can be selected independently of the evaporation design and can even exceed 110°C. In particular, in one embodiment, a speed of the working medium compressor of the first compression heat pump is varied in order to adjust the temperature level for evaporation.In particular, in one embodiment, the speed of the working fluid compressor of the first compression heat pump is varied to adjust the dry matter content of the concentrated carbohydrate-water mixture, i.e., the resulting thick juice. In particular, the speed of the working fluid compressor of the first compression heat pump is selected such that the temperature level for evaporation in the initial separation stage is approximately 120°C.

[0051] Alternatively or additionally, the speed of the working medium compressor of the second compression heat pump is varied to adjust the temperature level for crystallization. In particular, in one embodiment, the speed of the working medium compressor of the first compression heat pump is varied to adjust the supersaturation of the carbohydrate-water mixture for crystallization. In particular, the speed of the working medium compressor of the second compression heat pump is selected such that the temperature level for crystallization is approximately 65°C at 0.25 bar absolute.

[0052] The determining parameter for temperature selection in the at least one evaporation unit is no longer crystallization, but rather the target temperature to be achieved during juice heating. By adjusting the connection of the evaporation units, the required heating steam temperatures are reduced, which also reduces the equivalent heat exposure time. The increased space / time yield in the at least one crystallization unit ("sugar house") is achieved, on the one hand, by improved mass transfer to the crystal and, on the other hand, by increasing the temperature differences due to higher initial temperatures of the magma in the cooling crystallization.

[0053] The procedure proposed here proves to be particularly advantageous in the production of crystalline sucrose or crystalline isomaltulose.

[0054] In one embodiment, the separation device comprises a plurality of evaporation units and exactly one crystallization unit.

[0055] According to a further development of the invention, a carbohydrate-water mixture from the at least one evaporation unit is supplied to the at least one crystallization unit. In particular, the carbohydrate-water mixture is first concentrated or thickened in the at least one evaporation unit, wherein, in particular, a thick juice is produced from a thin juice. Subsequently, a carbohydrate contained in the concentrated carbohydrate-water mixture is crystallized in the at least one crystallization unit, wherein the carbohydrate is precipitated, in particular, from the thick juice. In particular, sucrose or isomaltulose is crystallized from the concentrated carbohydrate-water mixture or thick juice, in particular a sugar solution, in the at least one crystallization unit.

[0056] In one embodiment, the crystallization unit and the evaporation unit are directly connected to each other via a product stream of the carbohydrate-water mixture. This allows, in particular, continuous process control.

[0057] In another embodiment, the crystallization unit and the evaporation unit are separated from each other with respect to the product flow by an intermediate storage facility for the carbohydrate-water mixture. The intermediate storage of the carbohydrate-water mixture, in particular the concentrated or thickened mixture, advantageously allows for independent, particularly demand-driven, process control of the various processes.

[0058] Alternatively or additionally, the at least one evaporation unit and the at least one crystallization unit, in particular the first compression heat pump and the second compression heat pump, are operated thermally separately from one another. This, in particular, allows for thermal separation of the various processes from one another, coupled with the advantages already explained.

[0059] Alternatively, it is possible for waste heat from the at least one evaporation unit, in particular embodied by vapor from the at least one evaporation unit, to be used as a heat source for the second compression heat pump. This advantageously allows waste heat from the concentration or thickening process to be used in the crystallization process.

[0060] According to a further development of the invention, the compression heat pump is electrically driven. The reuse of waste heat as recycled heat with the simultaneous supply of heat pump heat generated mechanically via an electric drive advantageously enables a significant substitution and thus reduction, or possibly even avoidance, of the useful heat initially fed into the process, generated thermally, particularly through the combustion of fossil fuels.In particular, the amount of steam initially fed into the process from a boiler house can be reduced—possibly, depending on the process, even reduced to zero—or the same amount of steam initially fed from the boiler house can be used much more efficiently, particularly for separating a larger amount of water from the carbohydrate-water mixture, particularly for processing a larger amount of carbohydrate-water mixture. Depending on the method of generating the electrical energy to drive the compression heat pump, considerable cost savings, and not least significant carbon dioxide emissions, can be achieved. Thus, a significant decarbonization of the process can be achieved.

[0061] In one embodiment, the compression heat pump is powered by electrical energy from renewable sources. In this case, in particular, the process proposed here exhibits significantly lower carbon dioxide emissions than conventional processes for separating water from a carbohydrate-water mixture. In particular, thermally generated heat from fossil fuels is effectively replaced by heat generated mechanically via the electrically driven working fluid compressor, which ultimately results from renewable sources.

[0062] In another embodiment, the compression heat pump is driven by electrical energy which is provided at least partially by a generator which is drive-connected to a heat engine, in particular an internal combustion engine, in particular a gas turbine.

[0063] Alternatively or additionally, the compression heat pump is mechanically driven by a heat engine, in particular an internal combustion engine, in particular a gas turbine, in particular via a transmission. This also represents a very efficient and cost-effective way to mechanically provide heat for the separation of water from the carbohydrate-water mixture.

[0064] In particular, the internal combustion engine, in particular the gas turbine, is operated with biogas or another fuel gas from a renewable source, so that in this case, too, significant carbon dioxide emissions are effectively saved and decarbonization effects are achieved. In one embodiment, waste heat from the heat engine is used as additional heat—in particular via a third heat transport device—that is, it is additionally fed into the useful heat or used as part of the useful heat, in particular, it is supplied to the heating mass flow.

[0065] In one embodiment, an evaporation unit is used as at least one first separation unit and a crystallization unit is used as at least one second separation unit, wherein thermal secondary energy of the crystallization unit is used to extract recycling heat, which is fed back to the crystallization unit by means of a compression heat pump, wherein the compression heat pump is driven directly and / or indirectly, that is to say in particular electrically and / or mechanically, by a heat engine, wherein waste heat from the heat engine - in particular via a third heat transport device - is used as additional heat for the evaporation unit, that is to say additionally fed into the useful heat supplied to the evaporation unit or used as part of the useful heat, that is to say in particular fed to the heating mass flow supplied to the evaporation unit.Alternatively or additionally, waste heat from the heat engine - in particular via the third heat transport device or a fourth heat transport device - is used in a corresponding manner as additional heat for the crystallization unit.

[0066] In particular, in one embodiment, an evaporation unit is used as at least one first separation unit, wherein recycling heat is extracted from thermal secondary energy of the evaporation unit and fed back to the evaporation unit by means of a first compression heat pump, wherein a crystallization unit is used as at least one second separation unit, wherein recycling heat is extracted from thermal secondary energy of the crystallization unit and fed back to the crystallization unit by means of a second compression heat pump, wherein the second compression heat pump is driven directly and / or indirectly, that is to say in particular electrically and / or mechanically, by a heat engine, wherein waste heat of the heat engine - in particular via a third heat transport device - is used as additional heat for the evaporation unit,This means that it is additionally fed into the useful heat supplied to the evaporation unit or used as part of the useful heat, which means, in particular, that it is fed into the heat mass flow supplied to the evaporation unit. Alternatively or additionally, waste heat from the heat engine—in particular via the third heat transport device or a fourth heat transport device—is used accordingly as additional heat for the crystallization unit.

[0067] In one embodiment, the crystallization unit is a crystallization unit of a sugar factory, particularly configured for sucrose crystallization. Alternatively or additionally, the evaporation unit is a juice evaporation facility of the sugar factory.

[0068] According to a further development of the invention, a plurality of separation units are operated as the at least one separation unit, with each separation unit of the plurality of separation units discharging a waste stream, with at least one of the waste streams being used as a heat source for another process. Advantageously, the heat contained in the various waste streams can thus be efficiently used for other processes, for example, for heating factory premises or other industrial, chemical, biological, and / or food-processing processes—particularly in the same factory or plant.

[0069] Alternatively or additionally, at least one of the waste streams can be used as a heat source for preheating the carbohydrate-water mixture, in particular before the carbohydrate-water mixture enters a first separation unit of the plurality of separation units in the flow direction of the carbohydrate-water mixture - that is to say along the sequence defined by the product stream.

[0070] According to a further development of the invention, it is provided that - as already described above - the useful heat supplied to the high-temperature side consists of the recycling heat increased by the heat pump heat of the compression heat pump.

[0071] Alternatively, the useful heat comprises, in addition to the recycling heat increased by the heat pump heat of the compression heat pump, also additional heat, wherein the additional heat is supplied - in particular exclusively - on the high-temperature side of the at least one separation unit, in particular on a hot side of the working medium circuit.

[0072] The object is also achieved by providing a separation device for separating water from a carbohydrate-water mixture, which has at least one separation unit, wherein the at least one separation unit has a product inlet for introducing the TI

[0073] Carbohydrate-water mixture into the separation unit and a product outlet for discharging a partially dehydrated carbohydrate-water mixture, wherein the separation unit is configured to separate water from the carbohydrate-water mixture, wherein the at least one separation unit has a useful heat inlet on a high-temperature side for supplying useful heat - as primary thermal energy - and a secondary energy outlet on a low-temperature side for discharging secondary thermal energy, wherein the separation device has a compression heat pump with a closed working medium circuit and is configured to extract recycling heat from the secondary thermal energy discharged via the secondary energy outlet and to feed the recycling heat back to the useful heat inlet on the high-temperature side at a temperature level of greater than 100 °C by means of the compression heat pump.In connection with the separation device, the advantages that have already been explained in connection with the method arise in particular.

[0074] In one embodiment, the separation device is configured to carry out a method according to the invention or a method according to one or more of the previously described embodiments.

[0075] In particular, the separating device, or elements of the separating device, have at least one feature previously explained in connection with the separating device or an element of the separating device, or a combination of these features.

[0076] In one embodiment, the useful heat inlet and the secondary energy outlet are arranged on the same spatial-geometric side of the at least one separation unit. In another embodiment, the useful heat inlet and the secondary energy outlet are arranged on different, in particular opposite, spatial-geometric sides of the at least one separation unit. In particular, in one embodiment, the heating medium and the product can be conducted in countercurrent, while in the other embodiment, the heating medium and the product have the same flow directions, at least in some regions within the separation unit. In accordance with the various embodiments described here, the terms "high-temperature side" and "low-temperature side" do not necessarily describe different spatial-geometric sides of a separation unit, but are to be understood merely in thermal terms.In certain embodiments, they can be assigned to the same spatial-geometric side or, in certain other embodiments, to different spatial-geometric sides of a separation unit.

[0077] In one embodiment of the separation device, the product inlet and the useful heat inlet of the at least one separation unit are spatially and / or fluidically separated from one another. In particular, in this embodiment, the useful heat inlet is configured to introduce the useful heat, embodied by a heating medium as the heating mass flow, into the separation unit. The heating medium is, in particular, steam, in particular water vapor, air, in particular hot air, a heat transport medium, or vapor generated, in particular, from a heating condensate, i.e., a condensate formed from the heating medium, of the separation unit having the useful heat inlet, i.e., the same separation unit.

[0078] In another embodiment of the separation device, the product inlet is identical to the useful heat inlet, whereby in this case the useful heat, embodied by the carbohydrate-water mixture itself, is introduced into the separation unit as the heating mass flow. In particular, the carbohydrate-water mixture is heated, in particular superheated, in a superheating device of the separation device, where it is subsequently introduced into an evaporation chamber of the separation unit, where water evaporates—in particular abruptly—from the carbohydrate-water mixture, a process also referred to as flash steam.

[0079] In one embodiment, the separation device has a plurality of separation units. In one embodiment, the separation device exclusively has separation units in which the product inlet is spatially and / or fluidically separated from the useful heat inlet. In another embodiment, the separation device exclusively has separation units in which the product inlet is identical to the useful heat inlet. In yet another embodiment, the separation device has at least a first separation unit in which the product inlet is spatially and / or fluidically separated from the useful heat inlet, wherein the separation device additionally has at least one second separation unit in which the product inlet is identical to the useful heat inlet.

[0080] In one embodiment, the separation device comprises only separation units, each with at least one heating surface. In another embodiment, the separation device comprises only separation units, each with an evaporation chamber. In yet another embodiment, the separation device comprises at least one separation unit with at least one heating surface and at least one further separation unit with an evaporation chamber.

[0081] The secondary energy output is in particular designed to discharge the thermal secondary energy in the form of steam, in particular water steam, in particular a vapor formed from the carbohydrate-water mixture, or in the form of hot air, and / or in the form of a condensate, in particular a condensate formed from the vapor formed from the carbohydrate-water mixture or the heating condensate.

[0082] In one embodiment, the separation device is configured to feed the recycled heat back to the useful heat input of the same separation unit on its high-temperature side.

[0083] In another embodiment, the separation device is configured to resupply the recycled heat to the useful heat input of a separation unit on the high-temperature side other than the separation unit from whose secondary energy output the recycled heat originates. In particular, the separation device is configured to extract the recycled heat from a separation unit located downstream of a heat flow through the separation device comprising a plurality of separation units and to supply it to a separation unit located upstream of the heat flow.

[0084] In particular, the separation device comprises a plurality of separation units that are thermally interconnected and arranged in series along a heat flow—in particular along a temperature gradient, and preferably additionally along a pressure gradient. The separation device is configured to extract the recycled heat of the thermal secondary energy on the low-temperature side of a downstream separation unit of the plurality of separation units and to supply it, by means of the compression heat pump, to the high-temperature side of an upstream separation unit of the plurality of separation units. The upstream separation unit is arranged upstream of the downstream separation unit along the heat flow.In particular, the downstream separation unit is a last separation unit of the plurality of separation units along the heat flow, and the upstream separation unit is a first separation unit of the plurality of separation units along the heat flow.

[0085] In particular, the secondary energy output is configured to discharge from the separation unit a waste stream carrying away the water separated from the carbohydrate-water mixture, in particular in the form of steam, in particular water steam, in particular a vapor, or in the form of air, in particular moist hot air, and / or in the form of a condensate.

[0086] In one embodiment, the secondary energy output is fluidically connected to the first working medium heat exchanger, in particular the working medium evaporator, of the compression heat pump, so that the recycling heat can be extracted from the mass flow directly in the first working medium heat exchanger and used to evaporate the working medium.

[0087] In another embodiment, the separation device comprises a first heat transport device which is arranged and configured to thermally connect the mass flow to the first working medium heat exchanger, in particular the working medium evaporator.

[0088] In one embodiment, the useful heat inlet, or - in particular if the product inlet is identical to the useful heat inlet - the product inlet is fluidically connected to the second working medium heat exchanger, in particular the working medium condenser, of the compression heat pump, so that the recycling heat - in particular augmented by the heat pump heat - can be supplied to at least a partial heating mass flow of the heating mass flow upstream of the useful heat inlet or the product inlet directly in the second working medium heat exchanger, where it is released in particular as condensation heat of the working medium.

[0089] In another embodiment, the separation device comprises a second heat transport device arranged and configured to thermally connect the useful heat input or the product input, and thus the heating mass flow, to the second working medium heat exchanger, in particular the working medium condenser. In one embodiment, the separation device comprises an evaporation unit as the at least one separation unit. In another embodiment, the separation device comprises a crystallization unit as the at least one separation unit.

[0090] In one embodiment, the separation device comprises, as the at least one separation unit, at least one evaporation unit—as at least one first separation unit—and at least one crystallization unit—as at least one second separation unit. The separation device is configured to extract recycle heat from thermal secondary energy of the at least one evaporation unit and to resupply the recycle heat to the at least one evaporation unit by means of a first compression heat pump. The separation device is also configured to extract recycle heat from thermal secondary energy of the at least one crystallization unit and to resupply the recycle heat to the at least one crystallization unit by means of a second compression heat pump.In particular, the separation device comprises, as the compression heat pump, on the one hand, the first compression heat pump and, on the other hand, the second compression heat pump, in particular two compression heat pumps.

[0091] In one embodiment, the separation device comprises a plurality of evaporation units and exactly one crystallization unit.

[0092] In one embodiment of the separation device, the at least one crystallization unit is fluidically connected - in particular via a product line - to the at least one evaporation unit, so that a carbohydrate-water mixture from the at least one evaporation unit can be fed to the crystallization unit directly via the fluidic connection for crystallization.

[0093] In another embodiment, the separation device comprises an intermediate storage facility into which the carbohydrate-water mixture emerging from the at least one evaporation unit can be stored. The carbohydrate-water mixture can be withdrawn from the intermediate storage facility and fed to the at least one crystallization unit for crystallization. In particular, the at least one evaporation unit and the at least one crystallization unit are fluidically separated from one another or at least not directly connected to one another, with mass transport of the carbohydrate-water mixture from the evaporation unit to the crystallization unit being provided only via the intermediate storage facility.

[0094] In one embodiment, the separation device is configured to operate the at least one evaporation unit and the at least one crystallization unit, in particular the first compression heat pump and the second compression heat pump, thermally separated from one another.

[0095] In another embodiment, the separation device is configured to use waste heat from the at least one evaporation unit as a heat source for the second compression heat pump. In particular, the separation device has a thermal connection—in particular in the form of a vapor line—between the at least one evaporation unit and the second compression heat pump, in particular the first working medium heat exchanger, in particular the working medium evaporator of the second compression heat pump.

[0096] In one embodiment of the separation device, the compression heat pump has an electric machine, in particular an electric motor, as a drive for the working medium compressor. In particular, the compression heat pump is designed to be operated with electrical energy from renewable sources.

[0097] In another embodiment, the compression heat pump is configured to be operated by electrical energy provided by a generator that is drivingly connected to a heat engine, in particular an internal combustion engine, in particular a gas turbine. In particular, the separation device comprises such a generator and the heat engine that is drivingly connected to it, wherein the generator is electrically connected to the electric motor of the compression heat pump.

[0098] Alternatively or additionally, the compression heat pump is connected to the heat engine - preferably via a gearbox.

[0099] In one embodiment, the heat engine is designed as an internal combustion engine, in particular as a gas turbine, and is preferably configured to be operated with biogas or another fuel gas from renewable sources. In one embodiment, the separation device comprises a third heat transport device configured to supply waste heat from the heat engine to the high-temperature side of the at least one separation unit as additional heat, i.e., to additionally feed it into the useful heat or to use it as part of the useful heat, i.e., to supply the waste heat, in particular, to the heating mass flow.

[0100] In one embodiment, the separation device has an evaporation unit as at least one first separation unit and a crystallization unit as at least one second separation unit, as well as a compression heat pump, by means of which recycling heat is extracted from thermal secondary energy of the crystallization unit and fed back to the crystallization unit, wherein the compression heat pump is driven directly and / or indirectly, that is to say in particular electrically and / or mechanically, by a heat engine, wherein the separation device is designed to use waste heat from the heat engine - in particular via a third heat transport device - as additional heat for the evaporation unit, that is to say additionally feed it into the useful heat supplied to the evaporation unit or use it as part of the useful heat, that is to say in particular feed it to the heating mass flow supplied to the evaporation unit.Alternatively or additionally, the separation device is designed to use waste heat from the heat engine - in particular via the third heat transport device or a fourth heat transport device - in a corresponding manner as additional heat for the crystallization unit.

[0101] In particular, in one embodiment, the separation device comprises an evaporation unit as at least one first separation unit, as well as a first compression heat pump, by means of which recycling heat is extracted from the thermal secondary energy of the evaporation unit and fed back to the evaporation unit, wherein the separation device comprises a crystallization unit as at least one second separation unit, as well as a second compression heat pump, by means of which recycling heat is extracted from the thermal secondary energy of the crystallization unit and fed back to the crystallization unit, wherein the second compression heat pump is driven directly and / or indirectly, that is to say in particular electrically and / or mechanically, by a heat engine, wherein the separation device is designedto use waste heat from the heat engine—in particular via a third heat transport device—as additional heat for the evaporation unit, i.e., to additionally feed it into the useful heat supplied to the evaporation unit or to use it as part of the useful heat, i.e., in particular, to supply it to the heat mass flow supplied to the evaporation unit. Alternatively or additionally, the separation device is configured to use waste heat from the heat engine—in particular via the third heat transport device or a fourth heat transport device—in a corresponding manner as additional heat for the crystallization unit.

[0102] In one embodiment, the crystallization unit is a crystallization unit of a sugar factory, particularly configured for sucrose crystallization. Alternatively or additionally, the evaporation unit is a juice evaporation facility of the sugar factory.

[0103] In one embodiment, the separation device comprises a plurality of separation units, wherein each separation unit of the plurality of separation units is assigned a waste stream discharge line which is thermally connected to at least one further process, so that at least one of the waste streams of the separation units can be used as a heat source for a further process.

[0104] The invention is explained in more detail below with reference to the drawings, which show:

[0105] Figure 1 shows a first embodiment of a method and a separation device for separating water from a carbohydrate-water mixture;

[0106] Figure 2 shows a second embodiment of a method and a separation device for separating water from a carbohydrate-water mixture;

[0107] Figure 3 shows a third embodiment of a method and a separation device for separating water from a carbohydrate-water mixture;

[0108] Figure 4 shows a fourth embodiment of a method and a separation device for separating water from a carbohydrate-water mixture, and

[0109] Figure 5 shows a fifth embodiment of a method and a separation device for separating water from a carbohydrate-water mixture.

[0110] In general, for the purpose of describing the various embodiments in the figures, the following system of variables is introduced: A specific separation unit or thermal separation stage, on whose low-temperature side recycling heat is extracted, is designated by the variable x, which can assume values ​​from 1 to n, where n is the total number of separation units encompassed by a separation device in question and integrated into a common heat flow. The thermal secondary energy removed on the low-temperature side of the separation unit x, in particular embodied by a vapor, is designated B x The useful heat supplied on the high-temperature side of a separation unit, which at least partially comprises the returned recycling heat - in particular embodied by a vapor - is denoted by B x.ywhere y is the number of separation units, including the separation unit from which the recycling heat is removed, by which the recycling heat is recycled. If the recycling heat is recycled directly from the low-temperature side of a separation unit to the high-temperature side of the same separation unit, then y = 1. A heating condensate of the separation unit x is denoted by K x .i. A product condensate of the separation unit x is denoted by K x designated.

[0111] In particular, the useful heat B comprising at least part of the recycling heat extracted from the separation unit x and recycled through y stages is generally x.y the separation unit x- +1. In this separation unit x- +1 a heating condensate K x.y , a brother B x.y +i and a product condensate K x.y+i. Useful heat is supplied to the separation unit x in the form of a vapor B x -i; there a heating condensate K x .i and a brother B x The product condensate of vapor B x is called K x designated.

[0112] In particular, the invention integrates a closed, counterclockwise heat pump cycle by using a vapor B x as a heat source is condensed to produce a heating steam B x.y to be fed to a heating element of an upstream stage xy for heating. The heat provided by the working medium circuit on the high pressure side is fed in the working medium condenser to a condensate stream from stage x- +1 (K x.y ), which leads to its evaporation. This additionally generated heating steam quantity B x.yis fed to the heating element of the stage. The heat fed back from stage x to stage x- +1 results in a change in the evaporation capacity. This can be influenced by the circulated amount of working fluid in the compression heat pump. An adjustment of the dry matter content is thus possible without a material return transport of a heating medium or vapor when selecting the parameter y. Due to the closed heat pump circuit, the energy content of the vapor B x from separation stage x is raised to the exergetic level of a steam quality y stages ahead and thus exergetically higher. The heating element of stage x-y+1, which is heated by the heating steam B x.y is heated, but can also be compared to the heat source, which determines the energy content of the vapor B xrepresents different quality requirements for the heat transfer medium of the heating steam, since in the closed heat pump circuit only an energy and no mass transport from the heat source B x to heat sink B x.y However, instead of vapors, any form of liquid heat source - especially a condensate K x - from any usage level x, where the heat is transferred by cooling the liquid.

[0113] Fig. 1 now shows a first embodiment of a method and a separation device 1 for separating water from a carbohydrate-water mixture.

[0114] The separation device 1 has a separation unit 3, which in turn has a product inlet 5 for introducing the carbohydrate-water mixture 4 into the separation unit 3 and a product outlet 7 for discharging a partially dehydrated carbohydrate-water mixture 4. The separation unit 3 is designed to separate water from the carbohydrate-water mixture. The separation unit 3 has a useful heat inlet 11 on a high-temperature side 9 for supplying useful heat and a secondary energy outlet 15 on a low-temperature side 13 for dissipating secondary thermal energy.Furthermore, the separation device 1 has a compression heat pump 17 with a closed working medium circuit 19 and is designed to extract recycling heat from the thermal secondary energy discharged via the secondary energy output 15 and to feed the recycling heat back to the useful heat input 11 on the high-temperature side 9 at a temperature level of greater than 100 °C by means of the compression heat pump 17.

[0115] The first embodiment of the separation device 1 is designed to separate water from moisture-containing crop pieces as the carbohydrate-water mixture 4, in particular sugar beet pulp or chicory roots. In particular, the separation device 1 is designed for pulp drying in a sugar factory.

[0116] The first embodiment of the separation device 1 also has a drying stage 21 arranged upstream of the separation unit 3 along a product stream of the carbohydrate-water mixture 4; however, this can also be omitted in another embodiment and is therefore optional.

[0117] The compression heat pump 17 has - in particular in the specified order along a flow direction of a working medium in the closed working medium circuit 19 - an expansion valve 23 for expanding the working medium, a first working medium heat exchanger 25, in particular a working medium evaporator 27, a working medium compressor 29, here two working medium compressors 29 connected in parallel to one another in terms of flow technology, and a second working medium heat exchanger 31, in particular a working medium condenser 33.

[0118] In the first exemplary embodiment of the separation device 1 and thus also of the method, the useful heat is supplied to the separation unit 3 via a heating medium 34, here via supply air 35. The recycle heat is extracted from a waste stream 37, here exhaust air 39, which carries the water separated from the carbohydrate-water mixture. The waste stream 37 is fed directly to the first working medium heat exchanger 25, i.e., the working medium evaporator 27, in order to extract the recycle heat. Alternatively, in another exemplary embodiment, it is possible for the recycle heat from the waste stream 37 to be fed to the first working medium heat exchanger 25 via a first heat transport device.

[0119] The recycled heat is fed to a heating mass flow, here the mass flow of the heating medium 34, i.e., the supply air 35, wherein the heating mass flow is fed to the separation unit 3 on its high-temperature side 9 in order to thermally separate the water from the carbohydrate-water mixture 4. The recycled heat is fed to the heating mass flow, i.e., the supply air 35 in the first exemplary embodiment, from the second working medium heat exchanger 31, in particular the working medium condenser 33, via a heat transport device 41, referred to here as the second heat transport device 41 to distinguish it from the aforementioned first heat transport device. The second heat transport device 41 has a heat transport medium circuit 43, in particular with a liquid heat transport medium, wherein, for example, water or a heat transfer oil can be provided as the heat transport medium.The heat transfer medium circuit 43 comprises a third heat exchanger 45, through which the heat transfer medium flows on the one hand and the heating medium on the other hand, wherein the recycle heat—in particular, increased by the heat pump heat—is transferred to the heating medium 34. Alternatively, in another initial example, it is possible for at least a partial heating mass flow of the heating mass flow to be guided through the second working medium heat exchanger 31 upstream of the separation unit 3.

[0120] In the first exemplary embodiment shown here, the compression heat pump 17, in particular the working fluid compressor 29, are each driven by an electric machine 44, in particular an electric motor. They are preferably powered by electrical energy from renewable sources. Thus, heat otherwise provided from chemical energy, in particular by the combustion of fossil fuels, can advantageously be replaced by mechanically generated heat, in particular mechanically generated heat using electrical energy—in particular from renewable sources.

[0121] In the first exemplary embodiment, the useful heat supplied to the separation unit 3 during ongoing operation preferably consists entirely of the recycled heat—augmented by the heat pump heat. No further heat supply is then required during ongoing operation of the separation device 1. However, to start up the separation device 1, external heat, for example, by means of an electric air heater—particularly on the high-temperature side 9 and thus simultaneously on the hot side of the working fluid circuit 19—can be supplied—particularly as additional heat—until a sufficient amount of heat is available in the waste stream 37 for the extraction of recycled heat in autonomous operation.

[0122] In particular, the crop pieces are fed to the separation device 1 at a mass flow of 45 t / h with a dry matter content of 32%. After passing through the upstream drying stage 21, a mass flow of 20 t / h of crop pieces with a dry matter content of 70% results, which enters the separation unit 3 via the product inlet 5. A mass flow of 138,000 m 3 / h supply air 35 is introduced into the separation unit 7, wherein the supply air 35 is previously heated in the third heat exchanger 45 from 7 °C with a relative humidity of 77% to 100 °C with a relative humidity of 0.8%.

[0123] A mass flow of 16 t / h of crop pieces with a dry matter content of 90% is discharged from product outlet 7. The waste stream 37 has a temperature of 30 °C and a relative humidity of 99.9%. After passing through the first working fluid heat exchanger 25, where the recycle heat is released, the waste stream 37 still has a temperature of 25 °C and a relative humidity of 99.9%.

[0124] The electrical power of the working media compressors 29, in particular the electrical machines 44, amounts to a total of 2 MW - preferably 1 MW per working media heat exchanger 29.

[0125] The heat transfer medium in the heat transfer medium circuit 43 preferably has a temperature of 105°C throughout the heat transfer medium circuit 43 during operation and is evaporated in the second working medium heat exchanger 31, whereby condensation heat is extracted from the working medium and supplied to the heat transfer medium as heat of vaporization. The heat transfer medium is condensed in the third heat exchanger 45, whereby condensation heat is extracted from it and supplied to the heating medium 34. In an alternative embodiment, however, sensible heat transfers without phase transitions of the heat transfer medium are also possible, particularly if the heat transfer medium is designed as heat transfer oil.

[0126] Since the separation device 1 in the first embodiment has only one separation unit 3, from whose low-temperature side 13 the recycling heat is returned to its own high-temperature side 9, in the variable system explained above, x = 1, y = 1, n = 1, and B x.y = Bo. The thermal secondary energy is denoted by Bi.

[0127] Fig. 2 shows a second embodiment of a method and a separation device 1 for separating water from a carbohydrate-water mixture 4.

[0128] Identical and functionally identical elements are provided with the same reference symbols in all figures, so that reference is made to the preceding description in each case.

[0129] The second embodiment of the separation device 1 is designed to separate water from a sucrose-containing solution, in particular from thin juice for sucrose production. In particular, the separation device 1 according to the second embodiment is designed as an evaporation station of a sugar factory. The separation device 1 according to the second embodiment has a plurality of separation units 3, here in particular four separation units 3, which are thermally connected to one another and arranged one behind the other in series along a heat flow, in particular along a temperature gradient and along a pressure gradient. In the series of separation units 3, the temperature and pressure are highest in a first separation unit 3.1, with both the pressure and the temperature along the series of separation units 3 via a second separation unit 3.2 and a third separation unit 3.3 down to a fourth separation unit 3.4, so that the temperature and pressure in the fourth separation unit 3.4 are lowest.

[0130] In this embodiment, the separation units 3 are designed as evaporation units.

[0131] The useful heat is initially supplied to the first separation unit 3.1 via a heating medium 34, in this case heating steam 48, in particular water vapor, which in particular partially comprises boiler house heating steam 49 coming from a boiler house 47. The recycled heat is extracted from the thermal secondary energy on the low-temperature side 13 of a downstream separation unit 3 of the plurality of separation units 3, specifically here a fourth low-temperature side 13.4 of the fourth separation unit 3.4, and is supplied by means of the compression heat pump 17 to the high-temperature side 9 of an upstream separation unit 3 of the plurality of separation units 3, specifically here a first high-temperature side 9.1 of the first separation unit 3.1; according to the above, the first upstream separation unit 3.1 is arranged upstream of the fourth downstream separation unit 3.4 along the heat flow.In particular, in this second embodiment, the recycling heat of the thermal secondary energy is taken from the last separation unit 3.4 of the plurality of separation units 3 along the heat flow and supplied to the high-temperature side 9.1 of the first separation unit 3.1 of the plurality of separation units 3 along the heat flow.

[0132] In particular, the recycling heat is supplied to the heating mass flow of the heating medium 34, here the boiler house heating steam 49, from the second working medium heat exchanger 31 of the compression heat pump 17.

[0133] The separation units 3 each have at least one heating surface 51, preferably a plurality of heating surfaces 51, which are exposed to the heating steam 48 on a heating medium side 53 and are in thermal contact, in particular in contact with the carbohydrate-water mixture 4 on a product side 55 facing away from the heating medium side 53. In particular, the at least one heating surface 51 of the first separation unit 3.1 is exposed to the heating medium 34, which condenses on the heating surface 51 to form a heating condensate 57 and transfers the condensation heat to the carbohydrate-water mixture 4. The heating condensate 57 of the first separation unit 1 thus produced is fed at least in part - in particular by means of the second heat transport device 41 - to the second working medium heat exchanger 31 of the compression heat pump 17, evaporated therein in turn and then fed as recycle steam 59 to the boiler house heating steam 49.The heating steam 48 supplied to the first separation unit 3.1 thus comprises, in part, the boiler house heating steam 49 flowing from the boiler house 47 and, in part, the recycle steam 59 formed from the heating condensate 57. In particular, in this exemplary embodiment, a partial heating mass flow in the form of the heating condensate 57 is passed through the second working medium heat exchanger 31, where this partial heating mass flow absorbs the recycle heat—augmented by the heat pump heat. The partial heating mass flow in the form of the recycle steam 59 formed in the second working medium heat exchanger 31 from the heating condensate 57 is then combined with the remaining heating mass flow, and the entire heating mass flow is supplied to the first high-temperature side 9.1 of the first separation unit 3.1.

[0134] Preferably, the heating condensate 57 is first collected in a collecting tank 61. Preferably, a distribution device 63, which may be configured in particular as a pump or a valve, determines which portion of the heating condensate 57 is fed to the second working medium heat exchanger 31. The remaining portion of the heating condensate 57 not fed to the second working medium heat exchanger 31 is preferably fed—in particular after cooling in a cooler 65—to a feedwater tank 67 of a steam generator (not shown) of the boiler house 47.

[0135] The recycling heat is extracted from the waste stream 37, here a vapor, which carries away the water separated from the carbohydrate-water mixture 4 in the fourth separation unit 3.4. The waste stream 37 is at least partially fed directly to the first working medium heat exchanger 25 of the compression heat pump 17. In the first working medium heat exchanger, the vapor is condensed into a product condensate 69, which is ultimately discharged—in particular for further use as a heat source in other processes. The compression heat pump 17 provides a material separation of the fourth low-temperature side 13.4 of the fourth separation unit 3.4 from the first high-temperature side 9.1 of the first separation unit 3.1, whereby these are merely thermally connected to one another via the compression heat pump 17. In this way, mixing of the product condensate 69 with the heating condensate 57 is advantageously avoided.

[0136] In each of the separation units 3, a vapor is produced by separating the water from the carbohydrate-water mixture 4. According to the previously explained system of variables, x = 4, y = 4 and n = 4, thus the heating steam 48 is charged with B x.y= Bo, the first vapor of the first separation unit 3.1 with Bi, the second vapor of the second separation unit 3.2 with B2, third vapor of the third separation unit 3.3 as B3, and finally the fourth vapor of the fourth separation unit 3.4 with / N, where the fourth vapor B4 is the waste stream 37. The separation units 3 following the first separation unit 3.1 are each heated by the vapor of the immediately preceding separation unit 3 - as a heating medium carrying useful heat. The thermal secondary energy of an immediately preceding separation unit 3 is thus at the same time at least partially the useful heat of the immediately following separation unit 3. In each of the separation units 3, a condensate is produced, where the condensates are referred to as Ko, Ki, K2, and K3 in analogy to the designation of the vapors.In particular, the second to fourth condensates Ki, K2, and Kj are each simultaneously product condensates of the respective separation units 3.1, 3.2, 3.3, which correspond in designation according to the index, and heating condensates of the immediately subsequent separation units 3.2, 3.3, 3.4 with an index increased by 1. The first condensate Ko accruing at the first separation unit 3.1 is the heating condensate 57. A fifth condensate K4 of the fourth vapor B4 is the product condensate 69. The condensates Ko, Ki, K2, Ks, K4 are each collected in collecting tanks 61 and finally discharged - in particular for further use as a heat source in other processes.

[0137] The vapors Bi, B2, and Bs are preferably used in part to preheat the carbohydrate-water mixture 4 in heaters 71, in addition to heating the immediately following separation unit 3. Furthermore, they are preferably partially condensed—in particular, a remaining portion—in the collection tanks 61 and accordingly discharged as condensate. The fourth vapor B4 is preferably partially used for further heat applications, for example, for juice purification, in particular raw juice, or for diffusion. The separation device 1 is preferably operated such that no portion of the fourth vapor B4 remains to be recooled during ongoing operation of the compression heat pump 17. In particular, the first working medium heat exchanger 25, as a heat sink, provides the driving force for the process.If, however, a portion requiring recooling remains—particularly during startup or shutdown of the separation device 1—this portion is preferably fed to a cooling tower 73 in order to provide sufficient driving force for the evaporation process. The supply line to the cooling tower 73 can be opened or closed, in particular as needed, via a valve device 75. In particular, the valve device 75 is closed during continuous operation and can be opened, in particular, to start up the separation device 1 and, in particular, remain open until the compression heat pump 17 can completely remove the waste heat of the fourth vapor B4 remaining after further heat uses.

[0138] In particular, a waste stream 37 in the form of the respective vapor Bi, B2, Bj, B4 is discharged from each separation unit 3 of the plurality of separation units 3, wherein at least one of the waste streams 37, in particular each waste stream 37, is used as a heat source for a further process.

[0139] In the second embodiment shown here, the product flow of the carbohydrate-water mixture 4 is designed parallel and in the same direction as the heat flow: The carbohydrate-water mixture 4 initially flows into the first separation unit 3.1 as thin juice and then passes through the second separation unit 3.2, the third separation unit 3.3 and finally the fourth separation unit 3.4 in the specified order, which it then leaves in concentrated form as thick juice.

[0140] In particular, the embodiment of the separation device 1 shown here is operated with the following parameters: 525 t / h of thin juice with a dry matter content of 18% are fed to the first separation unit 3.1 as the carbohydrate-water mixture 4, wherein the evaporation process in the four separation units 3 is conducted in such a way that a mass flow of 124 t / h of thick juice with a dry matter content of 72% results from the fourth separation unit 3.4.

[0141] While a conventional separation device 1 with a directly connected and thermally linked crystallization unit and six separation units 3 would have to be supplied with a mass flow of 100 t / h of heating steam from the boiler house 47 at a temperature level of 130 °C to 135 °C for the corresponding separation and crystallization performance, the separation device 1 shown here with its only four separation units 3 is only supplied with a mass flow of 41 t / h of boiler house heating steam 49 from the boiler house 47 at a temperature level of 120 °C at 1.96 bar absolute.This advantageously saves energy in two ways: firstly, with regard to the amount of steam to be generated in the boiler house 47, and secondly, with regard to the steam temperature, which requires a significantly reduced use of, in particular, fossil chemical combustion energy to generate steam; secondly, the risk of undesirable discoloration of the thick juice during the drying process is effectively reduced due to the lower thermal impact at the reduced temperature. In addition, 68 t / h of recycle steam 59 at a temperature level of 120 °C and 1.96 bar absolute are supplied from the second working medium heat exchanger 31, so that a total of 109 t / h of heating steam 48 at 120 °C and 1.96 bar absolute are supplied to the first separation unit 3.1 as heating medium 34.The energy for generating the recycle steam 59 is extracted, on the one hand, in the first working medium heat exchanger 25 from the waste stream 37 and thus from the fourth vapor B4, which has a total mass flow of 93.5 t / h at a temperature of 95 °C and a pressure of 0.84 bar absolute, of which 56.5 t / h are fed to the first working medium heat exchanger 25 and 37 t / h are fed to further heat uses. On the other hand, the energy comes from electrical power used to operate the working medium compressors 29, here a total of 6 MW. Reducing the number of separation units compared to a conventional process advantageously allows a high steam temperature to be maintained even downstream of the last separation unit, so that sufficient recycle heat can be extracted.

[0142] Fig. 3 shows a third embodiment of a method and a separation device 1 for separating water from a carbohydrate-water mixture 4. The fourth embodiment of the separation device 1 is designed to crystallize sucrose from thick juice or syrup by separating water from the thick juice or syrup. In particular, the separation device 1 according to the third embodiment is designed as a crystallization unit of a sugar factory.

[0143] In particular, the separation device 1 according to this exemplary embodiment has precisely one separation unit 3 designed as a crystallization unit. In this third exemplary embodiment, during ongoing operation of the separation device 1, the separation unit 3 is supplied with exclusively recycled heat—augmented by the heat pump heat—in the form of recycled steam 59 as useful heat on its high-temperature side 9. Thus, at least during ongoing operation, the useful heat consists of recycled heat—augmented by the heat pump heat—so that the energy required for the operation of the separation device 1, at least during ongoing operation, comes exclusively from the electrical power supplied to the working medium compressors 29, here 8 MW.To start up the separation device 1, heating steam—in particular as additional heat—can be fed in via a steam valve 77 in a manner not explicitly shown here, until the thermal secondary energy available on the low-temperature side 13 is sufficient for the autonomous operation of the separation device 1. The recycling steam 59 is generated in the second working medium heat exchanger 31 directly from the heating condensate 57. The recycling steam 59 thus condenses on the heating surface 51 of the separation unit 3 to form the heating condensate 57 and releases condensation heat to the carbohydrate-water mixture 4, and the heating condensate 57 is in turn evaporated in the second working medium heat exchanger 31 to form the recycling steam 59.The temperature preferably remains at least approximately constant along this circuit, an energy exchange or heat flow takes place only in the form of condensation heat in the separation unit 3 - with evaporation of water from the carbohydrate-water mixture 4 - and evaporation heat in the second working medium heat exchanger 31 - with condensation of the working medium.

[0144] In particular, in this embodiment, the entire heating mass flow is passed through the second working medium heat exchanger 31, where the heating mass flow absorbs the recycle heat—augmented by the heat pump heat—by converting the heating condensate 57 into recycle steam 59. The heating mass flow is then fed to the high-temperature side 9 of the separation unit 3 in the form of recycle steam 59.

[0145] The recycling heat is extracted from a portion of the waste stream 37 accumulating as vapors in the first working medium heat exchanger 25. The resulting product condensate 69 is preferably used to preheat raw juice from the sugar factory. Another portion of the waste stream 37 is preferably used to directly heat thick juice and / or raw juice. The vapors are first condensed in a pre-condenser represented as a first cooling tower 73.1, and the resulting condensate-cooling water mixture is then fed to the corresponding heat sink, i.e., the thick juice heating and / or the raw juice heating. The valve device 75 is preferably closed during operation, but can be opened, in particular, for starting up the separation device 1, in order to feed unused heat to a second cooling tower 73.2.

[0146] According to the variable system explained above, x = 1, y = 1, n = 1 and the recycle steam 59 is called B x.y = Bo. The vapor resulting as waste stream 37 is denoted by y. The heating condensate 57 is denoted by Ä7;, and the product condensate 69 by V / .

[0147] In particular, a mass flow of 51 t / h of recycle steam 59 at 102 °C and 1.09 bar absolute is fed to the separation unit 3. The waste stream 37 amounts to 36 t / h and leaves the separation unit 3 at a temperature of 65 °C and a pressure of 0.25 bar absolute. At the location of the first working medium heat exchanger 25, it still has a temperature of 60 °C.

[0148] In an embodiment not explicitly shown, but which can be thought of as a combination of the second embodiment and the third embodiment, the separation device 1 has at least one evaporation unit, in particular the four separation units 3 of the second embodiment, as at least one first separation unit, and additionally at least one crystallization unit, in particular the separation unit 3 of the third embodiment, as at least one second separation unit.In this case, recycling heat is extracted from the thermal secondary energy of the at least one evaporation unit and is fed back to the at least one evaporation unit by means of a first compression heat pump, while at the same time recycling heat is extracted from the thermal secondary energy of the at least one crystallization unit and is fed back to the at least one crystallization unit by means of a second compression heat pump.

[0149] In particular, the carbohydrate-water mixture 4 from the at least one evaporation unit, i.e., in particular, the thick juice, is fed to the at least one crystallization unit—directly or via an intermediate storage facility. In particular, the at least one evaporation unit and the at least one crystallization unit, in particular the first compression heat pump and the second compression heat pump, are operated thermally separately from one another.

[0150] Fig. 4 shows a fourth embodiment of a method and a separation device 1 for separating water from a carbohydrate-water mixture 4. The fourth embodiment of the separation device 1 is configured to separate water from a starch-containing medium as the carbohydrate-water mixture 4. In particular, the separation device 1 is configured as an evaporation station of a starch factory.

[0151] The separation device 1 according to the fourth exemplary embodiment has a plurality of separation units 3, here in particular four separation units 3, which are thermally connected to one another and arranged in series one behind the other along a heat flow, in particular along a temperature gradient and along a pressure gradient. In the series of separation units 3, the temperature and pressure are highest in a first separation unit 3.1, with both the pressure and the temperature decreasing along the series of separation units 3 via a second separation unit 3.2 and a third separation unit 3.3 up to a fourth separation unit 3.4, so that the temperature and pressure are lowest in the fourth separation unit 3.4.

[0152] The separation units 3 are also designed as evaporation units in the fourth embodiment.

[0153] In the fourth exemplary embodiment, too, during ongoing operation of the separation device 1 of the first separation unit 3.1 on its first high-temperature side 9.1, only recycled heat in the form of recycled steam 59 is supplied as useful heat. Thus, the useful heat consists of recycled heat at least during ongoing operation, so that the energy required for the operation of the separation device 1, at least during ongoing operation, comes exclusively from the electrical power supplied to the working medium compressors 29, here 1.6 MW. In particular, for starting up the separation device 1, boiler house heating steam 49 from a boiler house 47 can be fed in—in particular as additional heat—until the thermal secondary energy available on the fourth low-temperature side 13.4 of the fourth separation unit 3.4 is sufficient for the autonomous operation of the separation device 1.The recycle steam 59 is generated in the second working medium heat exchanger 31 directly from a heating condensate 57. The recycle steam 59 condenses on the heating surface 51 of the first separation unit 3.1 to form the heating condensate 57 and releases condensation heat to the carbohydrate-water mixture 4. The heating condensate 57 is then evaporated in the second working medium heat exchanger 31 to form the recycle steam 59. The temperature preferably remains at least approximately constant along this circuit.

[0154] In this exemplary embodiment, during operation, the entire heating mass flow, and in particular a partial heating mass flow for start-up, is conducted in the form of heating condensate 57 through the second working medium heat exchanger 31, where this heating mass flow absorbs the recycle heat—augmented by the heat pump heat. The heating mass flow is then fed in the form of recycle steam 59—optionally after combining with the remaining heating mass flow of the additional heat during start-up—to the first high-temperature side 9.1 of the first separation unit 3.1.

[0155] Preferably, the heating condensate 57 is first collected in a collecting tank 61.

[0156] The recycling heat is extracted from the waste stream 37, here a vapor, which carries away the water separated from the carbohydrate-water mixture 4 in the fourth separation unit 3.4. The waste stream 37 is at least partially fed directly to the first working-medium heat exchanger 25 of the compression heat pump 17. In the first working-medium heat exchanger 25, the vapor is condensed into a product condensate 69, which is ultimately discharged—in particular for further use as a heat source in other processes. The compression heat pump 17 provides a material separation of the fourth low-temperature side 13.4 of the fourth separation unit 3.4 from the first high-temperature side 9.1 of the first separation unit 3.1, whereby these are merely thermally connected to one another via the compression heat pump 17. In this way, mixing of the product condensate 69 with the heating condensate 57 is advantageously avoided.

[0157] In each of the separation units 3, a vapor is produced by separating the water from the carbohydrate-water mixture 4. According to the previously explained system of variables, x = 4, y = 4 and n = 4, thus the heating steam 48 is heated with B x.y= Bo, the first vapor of the first separation unit 3.1 with Bi, the second vapor of the second separation unit 3.2 with B2, third vapor of the third separation unit 3.3 as Bj, and finally the fourth vapor of the fourth separation unit 3.4 with B4, whereby the fourth vapor B4 is the mass flow 37. The separation units 3 following the first separation unit 3.1 are each heated by the vapor of the immediately preceding separation unit 3. In this case, a condensate arises in each of the separation units 3, whereby the condensates are designated as Ko, Ki, K2, and Ks analogously to the designation of the vapors. In particular, the second to fourth condensates Ki, K2, and Ks are each simultaneously product condensates of the separation unit 3.1, 3.2, 3.3, which correspond in designation according to the index, and heating condensates of the immediately following separation unit 3.2, 3.3, 3.4 with an index increased by 1.The first condensate Ko produced at the first separation unit 3.1 is the heating condensate 57. A fifth condensate K4 from the fourth vapor B4 is the product condensate 69.

[0158] In addition to heating the third separation unit 3.3, the second vapor B2 is used in part to preheat the carbohydrate-water mixture 4 in a first heater 71.1. The heating steam 48 is used in part in a second heater 71.2 for intermediate heating of the carbohydrate-water mixture 4.

[0159] The separation device 1 is preferably operated such that, during ongoing operation of the compression heat pump 17, a portion of 2.9 t / h of the fourth vapor B4 remains to be recooled, particularly since no further consumers or heat sinks are present in this exemplary embodiment. This portion to be recooled is preferably fed to a cooling tower 73, particularly to provide sufficient driving force for the evaporation process to achieve the desired dry matter content. The supply line to the cooling tower 73 can be opened or closed, in particular as required, via a valve device 75.

[0160] In the fourth exemplary embodiment shown here, the product flow of the carbohydrate-water mixture 4 is not designed along the heat flow: The carbohydrate-water mixture 4 first flows into the third separation unit 3.3 and then passes through the fourth separation unit 3.4, the second separation unit 3.2 and finally the first separation unit 3.1 in the specified order, from which it then leaves in a concentrated form. Between the fourth separation unit 3.4 and the second separation unit 3.2, the carbohydrate-water mixture 4 is intermediately heated by means of a portion of the second vapor B2 in the first heater 71.1. Between the second separation unit 3.2 and the first separation unit 3.1, the carbohydrate-water mixture 4 is intermediately heated by means of a portion of the heating steam 48 in the second heater 71.2.In particular, the sequence of the separation units 3 along the product stream and the heaters 71 ensures that the carbohydrate-water mixture 4 remains sufficiently fluid during concentration.

[0161] In particular, the embodiment of the separation device 1 shown here is operated with the following parameters: 43 t / h of syrup with a dry matter content of 32% are fed to the third separation unit 3.3 as the carbohydrate-water mixture 4, wherein the evaporation process in the four separation units 3 is carried out in such a way that a mass flow of 17 t / h of concentrated syrup with a dry matter content of 81% results from the first separation unit 3.1.

[0162] 6.8 t / h of recycling steam 59 are fed to the separation device 1 at a temperature level of 105 °C at 1.2 bar absolute. The fourth vapor B4 falls with a mass flow of

[0163] 7.4 t / h at a temperature level of 48 °C and a pressure of 0.11 bar absolute, of which

[0164] 4.5 t / h are fed to the first working medium heat exchanger 25. The remaining 2.9 t / h are fed to the cooling tower 73, particularly via the valve device 75.

[0165] Fig. 5 shows a fifth embodiment of a method and a separation device 1 for separating water from a carbohydrate-water mixture 4. The fifth embodiment of the separation device 1 is designed to separate water from a stillage from the bio-alcohol production as the carbohydrate-water mixture 4.

[0166] The separation device 1 according to the fifth exemplary embodiment has a plurality of separation units 3, here in particular four separation units 3, wherein at least the first three separation units 3.1, 3.2 and 3.3 are thermally connected to one another. These three separation units 3.1, 3.2, 3.3 are arranged one behind the other in series along a heat flow, in particular along a temperature gradient and along a pressure gradient. In the series of separation units 3, the temperature and pressure are highest in a first separation unit 3.1, wherein both the pressure and the temperature decrease along the series of separation units 3 via the second separation unit 3.2 up to the third separation unit 3.3, so that the temperature and pressure are lowest in the third separation unit 3.3.

[0167] The fourth separation unit 3.4 is separated from the heat flow of the remaining separation units 3 and heated separately, in particular by means of boiler house heating steam 49 as a carrier of useful heat from a boiler house 47. A waste stream 37 assigned to this fourth separation unit 3.4 and therefore referred to as fourth waste stream 37.4 is, in the exemplary embodiment illustrated here, at least largely discharged to a cooling tower 73, but can also be at least partially fed to the first working medium heat exchanger 25, so that recycling heat can then be extracted from this fourth waste stream 37.4 for the operation of the other separation units 3. In this way, the fourth separation unit 3.4 is then thermally connected to the remaining separation units 3.

[0168] The separation units 3 are also designed as evaporation units in the fifth embodiment.

[0169] Also in the fifth embodiment, during operation of the separation device 1 of the first separation unit 3.1 on its first high-temperature side 9.1, only recycling heat in the form of recycling steam 59 is supplied as useful heat.

[0170] The first, second, and third separation units 3.1, 3.2, 3.3 each have an evaporation chamber 79 arranged and configured such that evaporation of water from the superheated carbohydrate-water mixture 4, particularly in the form of flash steam formation, can occur in the evaporation chamber 79—particularly abrupt or sudden. Upstream of the evaporation chamber, the first, second, and third separation units 3.1, 3.2, 3.3 each have a superheating device 81 configured to superheat the carbohydrate-water mixture 4 before it enters the respective evaporation chamber 79. In particular, the pressure in the evaporation chamber 79 is lower than the pressure upstream of the respective evaporation chamber 79—particularly in the respectively assigned superheating device 81.

[0171] The useful heat is thus supplied to the respective high-temperature side 9 by superheating the carbohydrate-water mixture 4.

[0172] In particular, the recycle steam 59 is at least partially—a first portion—fed to the first superheating device 81.1 of the first separation unit 3.1, where it condenses, so that its condensation heat is used to superheat the carbohydrate-water mixture 4. A heating condensate 57 thus produced is fed into the second working medium heat exchanger 31 of the compression heat pump 17 and evaporated there, which in turn produces the recycle steam 59. A second portion of the recycle steam 59 is preferably used in a first additional superheater 83.1 of the first separation unit 3.1 to superheat the carbohydrate-water mixture 4. A third portion of the recycle steam 59 is preferably used in a second additional superheater 83.2 of the second separation unit 3.2 to superheat the carbohydrate-water mixture 4.

[0173] Accordingly, in this exemplary embodiment, the heating mass flow consists of the mass flow of the carbohydrate-water mixture 4 itself, with the recycling heat—augmented by the heat pump heat—being supplied to the heating mass flow from the second working-medium heat exchanger 31 via the second heat transport device 41. The second heat transport device 41 comprises, as the heat transport medium, the heating condensate 57 upstream of the second working-medium heat exchanger 31 and the recycling steam 59 formed therein downstream of the second working-medium heat exchanger 31.

[0174] The recycling heat is extracted in particular from the third waste stream 37.3, here a vapor, which carries off the water separated from the carbohydrate-water mixture 4 in the third separation unit 3.3, and / or - depending on the heat demand or specific design - from the fourth waste stream 37.4, also a vapor, wherein at least one of the waste streams 37.3, 37.4 is at least partially fed directly to the first working medium heat exchanger 25 of the compression heat pump 17. In the first working medium heat exchanger 25, the corresponding vapor is condensed into a product condensate 69, which is ultimately discharged - in particular for further use as a heat source in other processes.

[0175] In each of the separation units 3, vapor is produced by separating the water from the carbohydrate-water mixture 4. Since the fourth separation unit 3.4 is preferably not integrated into the heat flow of the other three separation units 3, it is not considered in the previously explained variable system. According to this system, x = 3, y = 3, and n = 3, thus the recycle steam is denoted by B x.y= Bo, the first vapor of the first separation unit 3.1 is designated Bi, the second vapor of the second separation unit 3.2 is designated B2, and the third vapor of the third separation unit 3.3 is designated Bj. The separation units 3 following the first separation unit 3.1 - in particular their respective superheating devices 81 - are each heated by the vapor of the immediately preceding separation unit 3, which supplies the respective useful heat. In each of the separation units 3, a condensate is produced in the superheating device 81, wherein the condensates are designated Ko, Ki, and K2 analogously to the designation of the vapors. In particular, the second and third condensates Ki and K2 are each simultaneously product condensates of the separation units 3.1, 3.2, which have the same designation according to the index, and heating condensates of the immediately following separation units 3.2, 3.3 with the index increased by 1.A third condensate K of the third vapor B is part of the product condensate 69.

[0176] A portion of the third and fourth mass flows 37.3, 37.4 to be recooled is preferably fed to the cooling tower 73. This portion can be adjusted, in particular, as required via a valve device 75.

[0177] In the fifth embodiment shown here, the product flow of the carbohydrate-water mixture 4 is designed at least partially counter to the heat flow: The carbohydrate-water mixture 4 first flows into the fourth separation unit 3.4 and then passes, in the specified order, successively through the third separation unit 3.3, the second separation unit 3.2, and finally the first separation unit 3.1, which it then leaves in a concentrated form. In particular, this ensures that the carbohydrate-water mixture 4 remains sufficiently fluid during the concentration process.The concentrated carbohydrate-water mixture 4 emerging from the evaporation chambers 79 of the first to third separation units 3 is returned in a predetermined proportion to the respective separation units 3 via the respective superheating device 81; the remaining proportion is fed to the separation unit 3 following along the product stream.

[0178] In particular, the embodiment of the separation device 1 shown here is operated with the following parameters: 83 t / h of stillage with a dry matter content of 15% are fed to the fourth separation unit 3.4 as the carbohydrate-water mixture 4, wherein the evaporation process in the four separation units 3 is carried out in such a way that a mass flow of 31 t / h of concentrated stillage with a dry matter content of 39% results from the first separation unit 3.1.

[0179] The fourth separation unit 3.4 is fed with 39 t / h of boiler house heating steam 49 at a temperature level of 94 °C and 0.79 bar absolute. The fourth waste stream 37.4 is generated with a mass flow of 41.7 t / h at 46 °C and a pressure of 0.1 bar absolute. The third vapor Bs is generated with a mass flow of 3.7 t / h at a temperature level of 46 °C and a pressure of 0.1 bar absolute. The first working medium heat exchanger 25 is fed with 3.8 t / h, in particular the third waste stream 37.3 and a small portion of 0.1 t / h from the fourth waste stream 37.4. The remaining 41.6 t / h of the fourth mass flow 37.4 are fed to the cooling tower 73, in particular via the valve device 75.

[0180] 6.2 t / h of recycling steam 59 at 102 °C and 1.1 bar absolute are fed to the first separation unit 3.1.

[0181] The power consumption of the working media compressor 29 is 1.4 MW.

Claims

REQUIREMENTS 1. Method for separating water from a carbohydrate-water mixture (4), wherein - the carbohydrate-water mixture (4) is introduced into at least one separation unit (3) in which water is separated from the carbohydrate-water mixture (4), wherein - to which at least one separation unit (3) on a high-temperature side (9) is supplied with useful heat in order to thermally separate the water from the carbohydrate-water mixture (4), wherein - thermal secondary energy is removed from at least one separation unit (3) on a low-temperature side (13), wherein - on the low-temperature side (13) of the thermal secondary energy, recycling heat is extracted, and wherein - the recycling heat is fed back to the high-temperature side (9) at a temperature level greater than 100 °C at least as part of the useful heat by means of a compression heat pump (17) having a closed working fluid circuit (19).

2. The method of claim 1, wherein the carbohydrate-water mixture (4) is selected from the group consisting of: a sucrose-containing medium, in particular a sucrose-containing solution, in particular thin juice or thick juice for sucrose production, sucrose syrup, an isomaltulose-containing medium, in particular an isomaltulose-containing solution, stillage from bioalcohol production, an alcohol-water solution, in particular a bioalcohol-water solution, a sugar alcohol-water medium, a starch-containing medium, and moisture-containing pieces of field crops, in particular sugar beet pulp or chicory roots.

3. A method according to any of the preceding claims, wherein a plurality of separation units (3) are used to separate the water from the carbohydrate-water mixture (4), the separation units (3) being thermally connected to one another and arranged in series along a heat flow, the recycling heat of the thermal secondary energy being extracted on the low-temperature side (13) of a downstream separation unit (3) of the plurality of separation units (3) and supplied to the high-temperature side (9) of an upstream separation unit (3) of the plurality of separation units (3) by means of the compression heat pump (17). is, wherein the upstream separation unit (3) is arranged along the heat flow upstream of the downstream separation unit (3).

4. Method according to claim 3, wherein the recycling heat of the thermal secondary energy of a separation unit (3) of the plurality of separation units (3) that is last along the heat flow is extracted and supplied to the high-temperature side (9) of a separation unit (3) of the plurality of separation units (3) that is first along the heat flow.

5. Method according to one of the preceding claims, wherein the useful heat is supplied to the at least one separation unit (3) via a heating medium (34), or wherein the useful heat is used to heat, in particular to superheat, the carbohydrate-water mixture (4) upstream of an evaporation chamber (79) of the at least one separation unit (3).

6. Method according to one of the preceding claims, wherein the recycling heat is extracted from a waste stream (37) that carries away the water separated from the carbohydrate-water mixture (4), wherein preferably the waste stream (37) is supplied at least partially directly to a first working medium heat exchanger (25), in particular a working medium evaporator (27), of the compression heat pump (17), or wherein the recycling heat from the waste stream (37) is supplied to the first working medium heat exchanger (25), in particular the working medium evaporator (27), via a first heat transport device.

7. A method according to any of the preceding claims, wherein the recycling heat is supplied to a heating mass flow which is supplied to the at least one separation unit (3) on the high-temperature side (9) in order to thermally separate the water from the carbohydrate-water mixture (4), wherein preferably - at least a partial heating mass flow of the heating mass flow upstream of the separation unit (3) is guided through a second working fluid heat exchanger (31), in particular a working fluid condenser (33), of the compression heat pump (17), or wherein The recycling heat is supplied to the heating mass flow from the second working fluid heat exchanger (31), in particular the working fluid condenser (33), via a second heat transport device (41).

8. Method according to one of the preceding claims, wherein the at least one separation unit (3) is at least one evaporation unit and at least one crystallization unit, wherein thermal secondary energy of the at least one evaporation unit is recycled heat which is supplied back to the at least one evaporation unit by means of a first compression heat pump (17), wherein thermal secondary energy of the at least one crystallization unit is recycled heat which is supplied back to the at least one crystallization unit by means of a second compression heat pump (17).

9. Method according to claim 8, wherein a carbohydrate-water mixture (4) from the at least one evaporation unit is supplied to the at least one crystallization unit, and / or wherein the at least one evaporation unit and the at least one crystallization unit, in particular the first compression heat pump (17) and the second compression heat pump (17), are operated thermally separately from each other.

10. Method according to one of the preceding claims, wherein the compression heat pump (17) is electrically driven, in particular with electrical energy from renewable sources.

11. Method according to one of the preceding claims, wherein a plurality of separation units (3) is operated as the at least one separation unit (3), wherein a mass flow (37) is discharged from each separation unit (3) of the plurality of separation units (3), wherein at least one of the mass flows (37) is used as a heat source for a further process.

12. Method according to one of the preceding claims, wherein the useful heat supplied to the high-temperature side (9) consists of the recycling heat increased by the heat pump heat of the compression heat pump (17), or wherein the useful heat comprises additional heat in addition to the recycling heat increased by the heat pump heat of the compression heat pump (17), wherein the additional heat is supplied - in particular exclusively - to the high-temperature side (9) which is supplied to at least one separation unit (3), in particular on a hot side of the working fluid circuit (19).

13. Separation device (1) for separating water from a carbohydrate-water mixture (4) with at least one separation unit (3), wherein - comprising at least one separation unit (3) having a product inlet (5) for introducing the carbohydrate-water mixture (4) into the separation unit (3) and a product outlet (7) for discharging a partially dehydrated carbohydrate-water mixture (4), wherein the separation unit (3) is configured to separate water from the carbohydrate-water mixture (4), wherein - which has at least one separation unit (3) on a high-temperature side (9) a useful heat input (11) for supplying useful heat and on a low-temperature side (13) a secondary energy output (15) for removing thermal secondary energy, wherein - the separation device (1) has a compression heat pump (17) with a closed working fluid circuit (19) and is set up to extract recycling heat from the thermal secondary energy discharged via the secondary energy output (15) and to feed the recycling heat back to the useful heat input (11) on the high-temperature side (9) at a temperature level greater than 100 °C by means of the compression heat pump (17).

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