Method and apparatus for treatment of process gas

Abstract

A method of treatment of process gas from an industrial process having a main stream and a secondary stream, wherein at least a portion of the process gas is treated by the following process steps: a first condensation step, in which a first condensate is separated out of the process gas; a first branching that takes place after the first condensation step, in which at least a portion of the process gas is branched off from the main stream as offgas into the secondary stream; a first further treatment step that takes place in the main stream after the first branching, in which at least a portion of the process gas is treated further after the first condensation step.

Description

[0001] Method and device for treating process gas

[0002] Description

[0003] Technical area

[0004] The present invention relates to a method for treating process gas from an industrial process.

[0005] State of the art

[0006] Process gas can be used as a medium in certain process steps in the manufacture of products in order to bring about certain technical effects such as drying in a process step. For the purposes of the present invention, a process gas is understood to be a gas or gas mixture which serves to have a technical effect on the product to be manufactured. Depending on the product and industrial process, the process gas can be an inert or non-inert gas or gas mixture. In particular in the case of non-inert process gas, air or air-like gas mixtures are often used. In this case, the term process air is often used synonymously with process gas. The process gas can absorb in industrial processes, whereby the process gas is released into the environment after leaving the industrial process. However, such operating materials can contain pollutants or solvents which have a negative impact on the environment.To reduce the negative environmental impact, this exhaust gas must be treated accordingly, also to comply with given legal limits for the exhaust gas released into the environment. If the process gas is process air, the exhaust gas is often referred to synonymously as exhaust air. A key distinguishing feature between exhaust gas and exhaust air can be the O2 concentration in the underlying gas mixture. Pollutants or pollutant-containing solvents are understood to be substances that, at a certain quantity or concentration in the gas outlet, can harm plants, animals and / or people in the surrounding area. The pollutants can be, for example, solvents (e.g. NMP, NEP, TEP, EAA, GBL, etc.), hydrocarbons, nitrogen oxides, ammonia, hydrogen fluoride, etc.

[0007] Conventional process gas treatment devices often contain a

[0008] Main flow channel through which a process gas stream is passed. The

[0009] Main flow channel is typically between an outlet for discharging to

[0010] 1

[0011] Confirmation copy of the purified process gas from the industrial process and an inlet for introducing the same into a condenser, in particular, it connects the outlet to the inlet. The pollutants or solvents contained in the process gas can be condensed in the condenser, and the condensed pollutants or solvents can thus preferably be at least partially separated from the process gas. A portion of the treated process gas is often diverted from the main stream as exhaust gas to an exhaust outlet into the environment.

[0012] In the prior art, processes with a condensation step are known in particular, whereby condensates are separated from the process gas and solvents can thereby be recovered.

[0013] CA2214542A1 shows a process in which a solvent can be recovered during the production of lithium-ion batteries by condensing the solvent from solvent-containing process air.

[0014] The present invention relates to a method for treating process gas, in particular for recovering solvents used in industrial processes such as the production of lithium-ion batteries. The method comprises condensation processes operating at different temperature levels, wherein a solvent-containing condensate is separated from the process gas and subsequently fed to a recovery process. The present invention also relates to a device for treating process gas from an industrial process, in particular for carrying out a method according to the invention.

[0015] Description of the invention

[0016] The present invention is based on the object of creating an improved method for treating process gas from an industrial plant / industrial process, which results in increased flexibility of use while avoiding extreme operating costs and overly complex designs and achieving a strong cleaning effect of the process gas.

[0017] This object is achieved according to the invention by a method for treating process gas from an industrial process with a main stream and a secondary stream, wherein at least a portion of the process gas is treated using the following method steps: a first condensation step in which a first condensate is separated from the process gas; a first branching taking place after the first condensation step in which at least a portion of the process gas is branched off from the main stream as exhaust gas into the secondary stream; a first further treatment step taking place in the main stream after the first branching, in which at least a portion of the process gas is further treated after the first condensation step. The invention disclosed here can advantageously be used both for the treatment, in particular preparation or purification of process gas and process air, so that within the meaning of the invention the terms process gas and process air orExhaust gas and exhaust air are synonymous.

[0018] The first further treatment step can also comprise the addition of heat, a reduction in pressure, and / or a second supply of ambient air or process gas from outside the main flow, for example from a secondary flow. Particularly preferably, heat is added in the first further treatment step, the thermal energy having been obtained from the first condensation step. The addition of heat in the first further treatment step can therefore be understood as heat recovery. An exhaust gas within the scope of this invention can, in particular, be a process gas removed from the main flow or from a main flow channel. The exhaust gas can, for example, be discharged into the environment, but can also be fed into an industrial process and / or forwarded to at least one further process step for further treatment.

[0019] The inventors have discovered that it can be advantageous for the treatment of process gas to first treat a portion of the process gas in a first condensation step and then branch it off into a bypass channel. The remainder of the process gas is further treated in a subsequent treatment step. The first condensation step can take place in a more energetically favorable range, whereby a heat transfer medium can be used to cool the process gas, which is cooled down with less energy. Treating in a first condensation step can promote solvent recovery and simultaneously reduce the pollutant concentration in the exhaust gas. The volume flow branched off during the first branching into the bypass channel is typically smaller than the volume flow present in the main stream after the first branching.Preferably, after the first condensation step, the process gas is divided into at least two streams, for example, a main stream and a secondary stream. Even when branching into multiple secondary streams, the total branched volume flow, which is added together across all secondary streams, is preferably smaller than the existing volume flow remaining in the main stream downstream of the first branch.

[0020] In the context of this disclosure, "a" and "an" are to be read as indefinite articles unless expressly stated otherwise, and thus always as "at least one" or "at least one," respectively. Thus, after several first condensation steps, several second condensation steps may also be provided. The first or second condensation step can also be understood as a multi-stage first or multi-stage second condensation step, respectively.

[0021] In particular, a first or second condensation step can comprise multiple condensation processes (see below). A condensation stage can, for example, have a heat exchanger or heat sink through which the process gas is passed. In particular, two or more condensation stages can be connected in series. For example, two or more different heat exchangers or heat sinks can be arranged in series, which cool the process gas to different temperature levels. A condensation step can therefore comprise multi-stage cooling.

[0022] Directional terms such as "after" or "before" in the process generally refer to the direction of flow. For example, the phrase "after the first condensation step" or "before the second condensation step" should be understood as "downstream of the first condensation step" or "upstream of the second condensation step," respectively. A heat transfer medium can, in particular, be a cooling medium or a refrigerant. For example, the heat transfer medium can comprise water, ammonia, carbon dioxide, organic refrigerants, or inorganic refrigerants.

[0023] A heat transport medium can be used in a cooling stage to cool the process gas during a condensation step, wherein heat is extracted from the process gas in a heat shift in the cooling stage and transported away by means of the heat transport medium. The heat shift can be understood to mean that the thermal energy extracted from a medium is transferred to a medium at another location or in another process step. The heat transport medium can be a cooling fluid, in particular a cooling liquid, e.g., water, as described above. The heat transport medium can be spatially separated from the process gas; for example, the heat transport medium can circulate in a cooling circuit spatially separate from the process gas. Particularly preferably, several cooling stages in a condensation step have a respective heat transport medium, e.g.,a first heat transfer medium is used in the first cooling stage and a second heat transfer medium is used in the second cooling stage. Optionally, the cooling stages can also each have separate cooling circuits. The heat extracted from the process gas during cooling can then be at least partially returned to the process gas in a further treatment step. The heat transfer can thus take place between the condensation step and the further treatment step by means of the heat transfer medium, i.e., heat energy can be transferred from the process gas from the condensation step to the further treatment step. The heat transfer medium, in particular a cooling liquid, can thus ensure high cooling performance in the cooling stage. In particular, the cooling performance in an air-water heat exchanger can be higher than in an air-air heat exchanger.Preferably, a heat transfer medium is used to cool the process gas during the first cooling stage, with the heat extracted from the process gas in the first cooling stage being added back to the process gas in a further treatment step. The heat transfer can be achieved simply by pumping cooling media. Optionally, the heat transfer can also be achieved using a heat pump or a heat pipe.

[0024] The method according to the invention is preferably suitable for treating process gas that was involved in an industrial process, for example during the drying of a coating for the production of lithium-ion batteries or components thereof, in particular electrodes, separators and / or membranes for secondary batteries or fuel cells. Preferably, the main stream represents a continuous flow of the process gas in the method. Preferably, the main stream comprises the flow that is conducted from the industrial process to the first condensation step, i.e. preferably the majority, particularly preferably the entire gas stream of the process gas conducted to the first condensation step. The spatial extent of the main stream also comprises, in particular, the flow space in which the first condensation step takes place.By analogy, this also applies to the flow space of the secondary stream, where the flow interacts with a solid, for example, in the case of a concentrator or a filter. This is especially the case when an adsorber is used.

[0025] In a preferred embodiment of the invention, the first further treatment step comprises heating and / or reducing the pressure, and / or supplying gas from outside the main stream, in particular air from an ambient environment. At least a portion of the process gas is treated with the following process step: returning process gas after the first condensation step to the industrial process. The term "after the first condensation step" is to be understood in particular as "downstream of the first condensation step"; the process gas can, in particular, only be returned after the first further treatment step.

[0026] The gas from outside the main stream can, for example, at least partially be process gas from one or more industrial processes. It is also conceivable that the gas can originate at least partially from at least one branched secondary stream, in which the gas flowing in the secondary stream has been further treated or conditioned. In certain cases where the ambient temperature and / or the relative saturation of the ambient air is below a certain value, for example, when the ambient air is dry or hot and dry enough, it may be preferable to add ambient air to the process gas, for example, to reduce the relative saturation during the first further treatment step.

[0027] The first further treatment step after the first branching can precondition the process gas, particularly for use in an industrial process, and reuse the process gas for energy recovery, for example, by heating the process gas through heat recovery from a condensation step. The industrial process can preferably be the industrial process from which the process gas was fed to the first condensation step, in the sense of recirculating the process gas. However, it may also be useful to feed the process gas to another industrial process.When operating with advantageous ambient air temperatures, which allow a desired temperature and / or relative saturation to be set when ambient air is supplied into the main stream, this desired state of the process gas can be achieved optionally or alternatively by simply supplying ambient air, even without heating in the first further treatment step.

[0028] In a further preferred embodiment of the invention, a portion of the process gas is branched off from the main stream in a second branching step, which takes place after the first branching step, in particular after the first further treatment step, and is added to the exhaust gas, wherein the relative saturation of the exhaust gas branched off during the second branching step is lower than the relative saturation of the exhaust gas branched off during the first branching step. In particular, a measurement of the temperature and / or saturation can be carried out after the portion of the process gas branched off during the second branching step is added to the exhaust gas. Preferably, a flow rate of the process gas branched off during the second branching step can be adjusted based on the measured temperature and / or saturation.

[0029] After the first branching, a saturated exhaust gas may still be present. The exhaust gas can in particular be saturated with a gas mixture, for example a gas mixture comprising water vapor and at least one gaseous solvent. A relative saturation can therefore generally comprise a relative saturation of the water vapor and / or a relative saturation of the gaseous solvent. The exhaust gas branched off during the first branching can therefore have a high relative saturation. Handling a flow with a high relative saturation can be made more difficult due to the risk of condensate formation, for example on the surface of lines or ducts. During the second branching, process gas is preferably branched off from the main stream, which has been heated or preheated, for example, beforehand in the first further treatment step.After the process gas is heated, the heated process gas can now have a lower relative saturation than the relative saturation of the exhaust gas that was previously branched off from the process gas during the first branching. This heated partial process gas stream can be added to the saturated exhaust gas and reduce its overall relative saturation. The risk of condensate formation can thus be reduced. The addition of exhaust gas can also involve adding or admixing. In particular, the addition of branched process gas can result in homogeneous flow characteristics of the exhaust gas.

[0030] In a further preferred embodiment of the invention, at least a portion of the exhaust gas is treated using the following process steps: First, a second condensation step taking place after the first condensation step, in which a second condensate is separated from the process gas. Second, a second further treatment step taking place after the second condensation step, in which at least a portion of the exhaust gas is further treated after the second condensation step, comprising heating and / or reducing the pressure and / or filtering; and / or third, a concentration step taking place after the first condensation step, comprising at least one concentration stage for reducing the concentration of a pollutant, and / or fourth, filtering of the exhaust gas taking place after the first condensation step. Additionally or optionally, a portion of the branched off exhaust gas can be released into the environment after the first condensation step.This can be particularly the case in water-based industrial processes. In the second condensation step, a condensate can be separated, preferably using a demister, i.e., a separation device for separating water droplets suspended in the exhaust gas. Filtering the exhaust gas can also preferably take place after the second condensation step.

[0031] Analogous to the first treatment step, the second further treatment step can also include heat supply, pressure reduction, and / or a second supply of ambient air or process gas from outside the main stream, for example, from a secondary stream. Heat supply is particularly preferably carried out in the second further treatment step, with the thermal energy being obtained from the second condensation step. The heat supply in the second further treatment step can therefore be understood as heat recovery. The lowest exhaust gas temperature reached in the second condensation step can, in particular, be lower than the lowest process gas temperature reached in the first condensation step.For the recovery of solvent-containing condensate from the sidestream, it may be advantageous to additionally treat the exhaust gas with a second condensation step, wherein the process gas is cooled to a lower temperature in the second condensation step than in the first condensation step. Overall, this arrangement according to the invention allows a higher proportion of solvents to be separated from the process gas than is possible with a single condensation step. In particular, with TEP / EAA as solvent components in the process gas, the exhaust gas can preferably be cooled to below 0 °C, particularly preferably below -5 °C, -10 °C, or -15 °C, in the second condensation step.

[0032] Typically, the concentration step within the scope of the invention is carried out as an adsorption process using an adsorption wheel or adsorption carousel, whereby atoms or molecules of liquids or gases are deposited, i.e., adsorbed, on a solid surface. Within the scope of the invention, a concentration reducer can be configured as a device comprising a housing within which at least one adsorption wheel or adsorption carousel is arranged to reduce the pollutant concentration of an exhaust gas.

[0033] Filtering the exhaust gas is particularly preferably carried out after the second condensation step or after the concentration step. This process step can be optional if the pollutant concentration is already below the legal emission limits after the second condensation step or after the concentration step.

[0034] It is also conceivable to treat a portion of the exhaust gas with the second condensation step and another portion of the exhaust gas with the concentration step. Such a process arrangement can be particularly advantageous if the process gas contains different pollutant components that can be removed from the exhaust gas either more effectively by means of a condensation step or by adsorption. The process gas can be a gas mixture, with at least one component being condensable. In particular, such a component comprises a solvent. A solvent component can be, for example, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), triethyl phosphate (TEP), ethyl acetoacetate (EAA), dimethylacetamide (DMAc), γ-butyrolactone (GBL), propylene carbonate (PC), or even water, acetone, or alcohol.

[0035] In a further preferred embodiment of the invention, the following method steps are carried out for desorbing a concentrator: first, a portion of the exhaust gas is diverted before and / or after it is or has been concentrated in a concentration stage. Second, the diverted portion of the exhaust gas is heated to a desorption gas. Third, a desorption step using the desorption gas, wherein the desorption gas flows through a desorption region of a concentrator and absorbs at least one adsorbed pollutant. Fourth, the desorption gas is discharged as concentrate gas after flowing through the desorption region. Fifth, the concentrate gas is fed to a condensation step, in particular to the first condensation step and / or to a further condensation step, and / or to a concentration step.The branched part of the exhaust gas can in particular be heated to a temperature suitable for desorption, i.e. to a desorption temperature, whereby the desorption gas is generated.

[0036] The concentrator to be desorbed may preferably be the concentrator that cleans the exhaust gas, the exhaust gas having previously been diverted from the main stream.

[0037] Also preferably, the concentrator to be desorbed can be arranged in parallel to another concentrator, wherein the exhaust gas originating from the main stream is divided into at least two partial streams.

[0038] In principle, it is conceivable that the exhaust gas could be divided into at least two partial streams, each of which would be fed to a separate concentrator. In this case, the partial exhaust gas streams originate from a single main stream that has previously been treated in the first condensation step.

[0039] In principle, several industrial processes can run in parallel, with several parallel-connected initial condensation steps. In this case, several exhaust gas streams, each branched off from its own main stream, can be fed to a concentration step. The concentrator to be desorbed can therefore also be another concentrator treating a process gas originating from a separate industrial process.

[0040] The portion of the exhaust gas diverted before the concentration stage is referred to as raw gas. The portion of the exhaust gas diverted after the concentration stage is referred to as clean gas. The desorption gas can therefore be diverted in the form of raw gas or clean gas. Fresh air from the environment can also be used as desorption gas, whereby the fresh air is heated to a desorption temperature, thereby generating desorption gas. Since pollutants are removed from the exhaust gas in a concentration stage, the pollutant concentration in the exhaust gas can be higher before a concentration stage than after it. The pollutant concentration in the raw gas can therefore also be higher than the pollutant concentration in the clean gas.

[0041] In the process for desorbing a downconcentrator, the desorption gas is heated up and passed through a desorption zone of the downconcentrator to absorb adsorbed pollutants before being discharged from the desorption zone as concentrate gas. If raw gas is branched off as desorption gas instead of clean gas, the desorption gas may contain more pollutants and the concentrate gas may have a correspondingly higher pollutant concentration. This can be advantageous if the concentrate gas is passed to a condensation step, where the condensation step is carried out using a concentrate gas condenser, because correspondingly more pollutants can be separated as condensate. A further advantage of using raw gas as desorption gas could be lower equipment costs. A concentrate gas condenser can, in particular, be a condenser that primarily or exclusively treats concentrate gas.Particularly preferably, the concentrate gas is fed to the first condensation step and added to the process gas before the first condensation step.

[0042] In an alternative application scenario, clean gas can also be advantageously diverted as desorption gas. As explained above, the desorption gas can now contain fewer pollutants in the form of clean gas instead of raw gas. This can be advantageous, for example, if the desorption capacity of the desorption gas is to be increased. The desorption gas can absorb correspondingly more pollutants as it flows through the desorption zone and cleans the concentrator more effectively.

[0043] In another alternative application scenario, it may also be advantageous if the desorption gas, after flowing through the desorption zone, is fed to a concentration step as concentrate gas. The concentrate gas is preferably fed to the concentration step, particularly preferably to the first concentration stage of the concentration step. Because the desorption gas is in the form of clean gas instead of raw gas, the pollutant concentration of the concentrate gas can be lower and correspondingly less burden on the concentrator in the concentration stage.

[0044] In a further preferred embodiment of the invention, the following process steps are carried out: first, a concentrate gas is generated after flowing through the desorption region of a downconcentrator. Second, the concentrate gas is treated in a condensation step and / or concentration step. Third, the treated concentrate gas is fed to the first condensation step and / or to a concentration step, in particular to the first stage of the concentration step, and / or divided into at least two substreams before at least one of the substreams of the treated concentrate gas is fed to a condensation step and / or to a concentration step.

[0045] In this embodiment, the concentrate gas can first be treated in a condensation step, wherein a concentrate gas condenser is used. Alternatively, the concentrate gas is first treated in a concentration stage of a concentration step. The treated concentrate gas can be fed to the first condensation step; in particular, the treated concentrate gas can be added to the process gas before the first condensation step. Preferably, the treated concentrate gas is divided into, for example, two partial streams, wherein one partial stream is fed to the first condensation step and another partial stream is fed to another condensation step, for example to a condensation step, wherein a concentrate gas condenser is used. It is also conceivable for one partial stream to be fed to the first condensation step and another partial stream to the first concentration stage of the concentration step.

[0046] In a further preferred embodiment of the invention, a concentration step comprises at least two concentration stages arranged one behind the other in the flow direction of the exhaust gas, wherein the concentration stages each have a concentrator, wherein a concentrate gas from a concentration stage arranged downstream of at least one concentration stage is treated with the following process steps: the concentrate gas is mixed with the concentrate gas from an upstream concentration stage; and / or the concentrate gas is condensed in a condensation step and discharged by means of a further concentrate gas line after the condensation step; and / or the concentrate gas is guided to a concentration stage, in particular to the foremost concentration stage; and / or the concentrate gas is guided to the first condensation step.

[0047] This embodiment of the invention relates in particular to an advantageous gas flow path for the concentrate gas of a downstream concentration stage for desorbing a concentrator. This downstream concentration stage is thus arranged downstream of another concentration stage with respect to the main flow direction of the exhaust gas. For example, in a two-stage concentration step, this applies to the second stage; in a three-stage concentration step, this applies to the second and third stages.

[0048] The concentrate gas from the downstream concentration stage can be mixed with the concentrate gas from an upstream concentration stage, i.e., the two concentrate gas streams can be combined. The volume flow of concentrate gas can thus be increased, which in particular can increase the effectiveness of treating the combined concentrate gas streams. Preferably, the concentrate gas is condensed in a condensation step, for example, in a concentrate gas condenser, where a pollutant-containing condensate can be separated from the concentrate gas. The process with a condensation step in the concentrate gas condenser can be particularly advantageous if several concentrate gas streams are combined. The concentrate gas condenser can accordingly separate more pollutant-containing condensate. Nevertheless, the dimensions of the concentrate gas condenser can advantageously be designed for a larger throughput.

[0049] Also conceivable would be a stronger cooling of the concentrate gas condenser, which is designed for smaller throughputs of concentrate gas. By increasing the cooling during the condensation step using the concentrate gas condenser, the pollutant content in the separated condensate can be increased and the recovery of solvent-containing pollutants can be improved. Due to the smaller dimensions of the concentrate gas condenser, the energy consumption can be reduced.

[0050] Likewise, the concentrate gas is preferably directed to a concentration stage of a concentration step, particularly preferably to the frontmost concentration stage of the concentration step, i.e., the first concentration stage with respect to the main flow direction of the exhaust gas. The frontmost concentration stage can be designed, in particular, to concentrate a higher pollutant concentration, which is why the concentrate gas is advantageously preferably directed there.

[0051] Likewise, the concentrate gas is particularly preferably fed to the first condensation step. The concentrate gas can be added to the process gas before the first condensation step, and the pollutant concentration of the process gas can be increased before the first condensation step. The removal of as many pollutants as possible in the first condensation step can thus be advantageously configured. This is particularly advantageous if the concentrate gas contains solvent-containing pollutants, which can be recovered by means of a condensation step. In particular, as described above, heat recovery can be coupled with the first condensation step during cooling. By feeding the concentrate gas to the first condensation step, part of the thermal energy can be recovered from the concentrate gas.

[0052] In a further preferred embodiment of the invention, a concentration step comprises at least two concentration stages arranged one behind the other in the flow direction of the exhaust gas, wherein the concentration stages each have a concentrator, wherein a concentrate gas from a concentration stage which is arranged upstream of a further concentration stage, in the case of three concentration stages or more than the foremost concentration stage, is treated with the following process steps: the concentrate gas is mixed with the concentrate gas from a downstream concentration stage; and / or the concentrate gas is condensed in a condensation step before being discharged by means of a further concentrate gas line after the condensation step; and / or the concentrate gas is led to a concentration stage, in particular to the foremost concentration stage;and / or the concentrate gas is passed to the first condensation step.;

[0053] This embodiment of the invention particularly relates to an advantageous gas flow path for desorption in a concentration stage, which is the frontmost concentration stage with respect to the main flow direction of the exhaust gas. Thus, during treatment in the concentration step, the exhaust gas is first treated by this frontmost concentration stage before being treated downstream in a further concentration stage.

[0054] The gas flow of the concentrate gas in this embodiment can be carried out in a manner analogous to the gas flow of the concentrate gas of the downstream concentration stage described above.

[0055] In a further preferred embodiment of the invention, particularly at the start of operation or an interruption of operation or at the end of operation of the industrial process, at least a portion of the process gas, preferably completely, is filtered and / or purged after the first condensation step, in particular after the first further treatment step, and then led into the environment as exhaust gas, wherein fresh air from the environment is simultaneously led to the industrial process.

[0056] An interruption in operation can occur, for example, if an operating parameter is exceeded that requires an interruption in operation. The exhaust gas is preferably first filtered after the first condensation step before being released into the environment. It is also conceivable for the exhaust gas to be heated up in the first further treatment step after the first condensation step; however, when used with an activated carbon filter, the heating is typically limited to below 50 °C before the exhaust gas is filtered and released into the environment. The simultaneous introduction of fresh air from the environment can, in particular, be compensatory, i.e., at a similar volume flow ratio, to the discharge of fresh air. The industrial plant in which the industrial process takes place can therefore be flushed with fresh air using this method, and the relative saturation in the industrial plant can be kept below a certain level.

[0057] The present invention further relates to a device for treating process gas from an industrial process, preferably for carrying out a method as described above.

[0058] The present invention is based on the object of providing an advantageous device for the treatment of process gas from an industrial process.

[0059] This object is achieved according to the invention by a device for treating process gas from an industrial process, in particular for carrying out a method according to one of the preceding claims, having an outlet for discharging process gas from an industrial process, a heating element for heating the process gas, an inlet for introducing process gas into a first condenser which has a first cooling unit for cooling process gas, a first branching point for branching off at least a portion of process gas as exhaust gas into a bypass channel, wherein the heating element is arranged behind the first branching point.

[0060] In this embodiment, the heating element can be a heat exchanger connected to the first cooling unit, which, as described above, is operated, for example, by means of a coolant to achieve heat transfer. However, the heating element can also be an electric heating element, which can optionally also be used as a heating element in addition to a heat exchanger. The heating element can preferably be arranged in the first condenser. However, the heating element can also be connected to a heat source outside the first condenser and can also be arranged outside the first condenser.

[0061] Within the scope of the invention, a main or secondary flow channel can be understood as a flow channel through which a gas flow can be conducted. A channel can also be a gas or air line.

[0062] In a preferred embodiment, the device has a second branching point with which process gas is branched off into the bypass channel to reduce the relative saturation of the exhaust gas, wherein the first branching point is arranged behind the cooling unit and the second branching point is arranged behind the heating element.

[0063] The second branch point can preferably be located in the first condenser to achieve a compact design. However, it may also be advantageous to direct the process gas to the heating element outside the first condenser and then divert the exhaust gas into the bypass duct via the second branch point.

[0064] In a further preferred embodiment, the bypass duct for introducing at least a portion of the exhaust gas is connectable to: an inlet arranged downstream of the first condenser for introducing into a second condenser, wherein a second condensate is removed from the exhaust gas; and / or an inlet arranged downstream of the first condenser for introducing into a concentrator for reducing the concentration of a pollutant; and / or an inlet arranged downstream of the first condenser for introducing into a filter, in particular into an activated carbon filter.

[0065] Within the scope of this embodiment, the exhaust gas can be a process gas discharged from the main flow channel. The exhaust gas can, for example, be branched from the main flow channel into the secondary flow channel at the first branch point and / or at a second branch point. However, a portion of the exhaust gas can also be discharged from a process gas, for example, from another industrial plant or condenser operating in parallel with the first condenser.

[0066] Preferably, the bypass duct is connected to the inlet of the second condenser. The second condenser is particularly preferably arranged downstream of the first condenser with respect to the main flow direction of the exhaust gas. In the case of a multi-stage concentration step, several concentrators can be arranged in series. In such a case, the bypass duct can be arranged between two concentrators, whereby an exhaust gas treated in the front concentrator can be guided through the bypass duct to the rear concentrator.

[0067] In a further preferred embodiment for desorbing a concentrator, the device has a branching device for discharging a portion of the exhaust gas, wherein the branched portion of the exhaust gas is guided to a heating unit in which desorption gas is generated for desorbing the concentrator (80, 81, 85).

[0068] The branching device can preferably be designed in the form of a box or a chamber for diverting a flow, a valve or a flap.

[0069] The branching device can preferably be arranged in a downconcentrator, for example, as a valve or box within a downconcentrator. The branching device can, in particular, branch off or divert a portion of the exhaust gas, with the branched portion of the exhaust gas being guided into a separate gas duct to the heating unit. In the heating unit, the branched portion of the exhaust gas is preferably heated to a desorption temperature, generating desorption gas. The desorption gas can preferably leave the heating unit via a desorption gas line.

[0070] In a further preferred embodiment, the device comprises a downconcentrator with at least one adsorption and one desorption region, a concentrate gas line for guiding concentrate gas from the desorption region to an inlet for introducing concentrate gas into the first condenser and / or into a concentrate gas condenser and / or into an adsorption region of a downconcentrator.

[0071] The downconcentrator preferably has an adsorption, a desorption, and a cooling region for cooling a portion of the adsorption wheel. In a further preferred embodiment, the device has at least two downconcentrators arranged one behind the other with respect to the flow direction of the exhaust gas, each having at least one adsorption and one desorption region, a second concentrate gas line for discharging concentrate gas from the desorption region of a downstream downconcentrator, wherein the second concentrate gas line for introducing the concentrate gas is connectable to: an inlet for introducing it into an adsorption region of a downconcentrator; and / or a first concentrate gas line of an upstream downconcentrator for mixing with its concentrate gas; and / or the inlet for introducing it into the first condenser and / or an inlet for introducing it into a concentrate gas condenser.

[0072] In a further preferred embodiment, a further concentrate gas line for introducing a concentrate gas treated in a condenser and / or down-concentrator is provided with an inlet for introducing it into the first condensation step and / or an inlet for introducing it into a down-concentrator, and / or a splitter, wherein the treated concentrate gas is divided into at least two partial streams before at least one of the partial streams of the treated concentrate gas is guided with an inlet for introducing it into a condenser and / or into a down-concentrator.

[0073] In a further preferred embodiment, the device comprises at least two downconcentrators arranged one behind the other with respect to the flow direction of the exhaust gas, each having at least one adsorption and one desorption region, a first concentrate gas line for discharging concentrate gas from the desorption region of an upstream downconcentrator, in the case of at least three downconcentrators, the foremost downconcentrator, wherein the first concentrate gas line for introducing the concentrate gas is connectable to: an inlet for introducing it into the adsorption region of a downconcentrator; and / or an inlet for introducing it into a concentrate gas condenser; and / or the second concentrate gas line of a downstream downconcentrator for mixing with its concentrate gas; and / or the inlet for introducing it into the first condenser.The invention can fundamentally be used for any industrial plant and industrial process that utilizes process gas. The applications exemplified above in the technical background also apply to the devices and methods according to the invention. Advantageously, the device and method according to the invention can be used to treat a circulating process fluid or process air of a dryer, in particular circulating or recirculating air of a dryer, in particular from the process air of a production plant for producing battery electrodes. This typically occurs in a production plant for producing an electrical energy storage device, which is discharged from a drying plant in which electrodes are dried after a coating process.

[0074] Examples of implementation

[0075] The invention is explained in more detail below using several exemplary embodiments, without distinguishing between the different claim categories. Furthermore, it is clarified that the proposed solutions according to the invention can be applied to various different industrial processes in which, for example, an inert gas is used as the process gas. As an example, process air from an industrial process for producing battery electrodes is specifically discussed according to the invention below.

[0076] Character list

[0077] The drawings show:

[0078] Fig. 1 is a schematic representation of a device according to the invention with a first and a second condenser for treating process air from an industrial process for drying an electrode coating;

[0079] Fig. 1a is a schematic representation of a method according to the invention for treating process air. Fig. 1;

[0080] Fig. 2 is a schematic representation of a device according to the invention for treating diverted exhaust air by means of a concentrator;

[0081] Fig. 2a is a schematic representation of a method according to the invention for treating diverted exhaust air, as shown in Fig. 2; Fig. 3 is a schematic representation of a device according to the invention for treating diverted exhaust air by means of two concentrators;

[0082] Fig. 3a is a schematic representation of a method according to the invention for treating process air. Fig. 3;

[0083] Preferred embodiment of the invention

[0084] Fig. 1 shows schematically an embodiment of a device according to the invention for treating process air from an industrial process for the production of lithium-ion batteries.

[0085] Reference numeral 1 denotes an exemplary electrode coating system in which electrodes for producing lithium-ion batteries are coated in an electrode coating process S1. For example, one of the aforementioned solvents can be used; in particular, a mixture of, for example, TEP and EAA can also be used as the solvent. Process air A from the electrode coating process S1 is conveyed from an outlet 4a by a blower 61 into the main flow channel 5a to a first condenser 2. The blower 61 can also optionally be arranged between the condenser 2 and a first air heater 12. The temperature of the process air A is typically approximately 120°C, for example, in a range between 100 and 150°C upon entering the first condenser 2. In a first cooling unit 6, the process air A is successively cooled, preferably to approximately 15°C as the target temperature.The first cooling unit 6 optionally has a three- or multi-stage heat exchanger 6a in which heat is extracted from the process air. In the exemplary embodiment, the process air A is cooled in the three-stage heat exchanger 6a after the first stage to 60 °C, after the second stage to 30 °C, and after the third stage to 15 °C. However, it can also be provided to cool the process air A to a target temperature of up to approximately 10, 11, 12, 13, or 14 °C. In the first stage of the heat exchanger 6a, the process air is cooled, for example, from 120 °C upon entry to typically approximately 60 °C, in the second stage to, for example, approximately 40 °C, and finally in the third stage to the target temperature. The heat extracted in the first stage is transferred via a heat transfer device 15 to a first heating element 18, which is designed as a heat exchanger.The heat transfer device 15 can alternatively or additionally also comprise, for example, a heat pump, heat conductor, or the like. A heat conductor can be designed, for example, as a "heat pipe," wherein heat energy is transported by means of a solid material with good heat conduction. Preferably, the heat transfer medium is circulated in the heat transfer device 15, wherein heat energy is transported from the first cooling unit 6 to the first heating element 18. The first heating element 18 serves to return the heat extracted from the process air A in the heat exchanger 6a. The heat extracted in the second and third stages can optionally be fed to a further process (not shown) via separate heat transfer devices; for example, the heat can be coupled into the electrode coating process S1.

[0086] The heat exchanger 6a has a heat sink for each stage, preferably with vertically extending cooling fins, through which the process air A is passed. The cooling process creates the first condensate 16 on the surface of the cooling fins, which is then drained by gravity into a collecting container arranged below the first cooling unit 6. As a result of the cooling process in the first cooling unit 6, aerosol formation sometimes occurs. This creates aerosols that are transported with the main flow 5 through the first condenser 2. Therefore, a first separator 7 is preferably arranged downstream of the first cooling unit 6. This first separator 7 is designed as a "demister" or impact separator made of a wire mesh for separating fine droplets.The process air A flows through the first separator 7, whereby the first condensate 16 is again produced and is drained by gravity into the collecting tank arranged below the first cooling unit 6.

[0087] The separated first condensate 16 contains a first solvent 16a, which may, for example, be a mixture of TEP and EAA together with various by-products with similar condensation properties. The first condensate 16 is pumped from the collection vessel into a first condensate collector 13 outside the first condenser 2 and treated, preferably distilled, in a condensate recycling system 14a for recirculation to the electrode coating process 1a. In the condensate recycling system 14a, the first condensate 16 is separated into its respective solvent components (TEP and EAA) and enriched. Downstream of the first separator 7, a portion of the process air A is branched off from the main stream 5 at a first branching point 9 through a valve of a diversion device and diverted or discharged as exhaust air B into the bypass duct 31a to a second condenser 3.The portion of the process air conducted in the bypass duct 31a is preferably also referred to below as exhaust air B. A further portion of the process air A located in the main flow 5, which has already been heated by the heating element 18a, is branched off into the bypass duct 31a via an auxiliary line 46 connected to a second branching point 9a downstream of the first branching point 9, and is fed to or mixed with the exhaust air located in the bypass duct 31a. The amount of process air A branched off via the auxiliary line 46 is adjusted by means of a valve of the diverter 8. Instead of at least one of the valves, a flap or a throttle can equally be provided at at least one branching point. For example, a throttle can be used at the first branching point and an adjustable valve can be used at the second branching point to adjust the relative saturation of the exhaust air B.By supplying a portion of (re)heated process air A, the relative saturation of the exhaust air B in the bypass duct 31a can be reduced or the temperature of the exhaust air B in the bypass duct 31a can be increased, thereby facilitating its handling or further treatment. For example, undesirable condensation can be prevented. In this way, additional process air A can be branched off at the second branch point 9a and mixed with the exhaust air B previously collected at the first branch point 9. The temperature of the exhaust air B can be increased from 15 °C to approximately 20 °C by the addition, for example. While the exhaust air B branched off at the first branch point 9 in the coldest zone of the condenser 2 is almost 100% saturated with water vapor and / or solvent, the relative saturation of the process air A branched off at the second branch point 9a is significantly lower, while its temperature is comparatively higher.Therefore, the exhaust air B formed from the two partial streams has a reduced relative saturation of water vapor and, if appropriate, solvent, preferably a maximum of 80% or less. The volume flow at the second branch point 9a can preferably be adjusted by means of a control unit, whereby a measurement of the temperature, saturation, and / or solvent concentration is performed.

[0088] A second cooling unit 32 represents an essential component of the second condenser 3 and has at least a two-stage heat exchanger 32a in which heat, in particular further heat, is extracted from the exhaust air B. In the first stage, the exhaust air B is cooled, for example, from 20°C to -5°C and in the second stage to -20°C. Optionally, further stages can be added under certain circumstances in order to cool the exhaust air B to a target temperature below 0°C. Because the exhaust air B is cooled to <0°C, it may be particularly preferable to use a further, second cooling unit arranged in parallel. The further, second cooling unit can, for example, take over the cooling of the exhaust air B during a defrosting process of the second cooling unit 32. The heat extracted in the first stage is transferred via a heat transfer device 34 to a second heating element 19, which is designed as a heat exchanger.The previously extracted heat is at least partially added back to the exhaust air B in the secondary stream 31 via the second heating element 19. The heat extracted in the second stage is, if required, fed to a further process (not shown) via a separate heat pump. Both the separation of a second condensate 17 and the design of a second heat exchanger 32a and a second separator 33 (demister) are preferably carried out in a similar way to the first condenser 2. The second condensate has a second solvent 17a, wherein the second solvent 17a can have any composition (e.g. TEP and EAA). The second condensate 17, like the first condensate 16, is extracted from the solution shown in Fig.1 not shown collecting container into the second condensate collector 37 outside the second condenser 3 and processed, in particular distilled, in a condensate recycling plant 14b for return to the electrode coating process 1a, in which condensate recycling plant 14b the second condensate 17 is separated and enriched into its respective solvent components (e.g. TEP and EAA).

[0089] Downstream of the second separator 33, the exhaust air B of the secondary stream 31 is heated to 10°C by the second heating element 19 using the recovered heat from the second heat exchanger 32a. A second air heater 35 is arranged downstream of the second condenser 3, via which the exhaust air B is then further heated to 15°C before the exhaust air B is fed into a second further treatment device 39. In the second further treatment device 39, the exhaust air B in the example according to Fig. 1 is filtered through an activated carbon filter 36 before it is finally released into the environment 11 through an air outlet 21. Now back to the process air circuit of the main stream 5: Downstream of the separator ?, the process air A in the main stream 5 is reheated from approx. 15°C to approx. 60°C by the first heating element 18. In the example according to Fig.1, the process air A leaving the first condenser 2 is guided to a first air heater 12 for further conditioning via the main flow channel 5a.

[0090] The main flow channel 5a of the example according to Fig. 1 further comprises a second and third valve 23a, 23b. These valves 23a, 23b are preferably controlled or regulated by a second control unit 22, which can communicate with the first control unit 10. Alternatively, the valves can also be adjusted manually. The second valve 23a is preferably provided to regulate an air volume from the environment 11 through an air inlet 20 and, in doing so, to adjust a flow rate to the main flow channel 5a. During normal operation, the air inlet 20 can remain closed. So-called "web slots" can also be arranged in the electrode coating system 1 as air inlets, so that an air volume supplied to the electrode coating process 1a through the web slots preferably corresponds to an air volume diverted into the secondary flow 31.Web slots are typically slits in the housing through which, for example, a coated film is passed. However, particularly during an interruption in operation, the third valve 23b can also be completely closed; and the process air A can be completely guided by means of a valve (not shown) to a filter (not shown), in particular to an activated carbon filter, and filtered in the process, before the process air A is released into the environment as exhaust air B. At the same time, the second valve 23a is opened, whereby fresh air from the environment is guided to the industrial process to compensate for the discharged exhaust air B. This method can also be used, for example, at the start and / or end of operation.

[0091] The fresh air supplied from the environment 11 and the process air A from the condenser 2 are guided by means of the main flow channel 5a through the first air heater 12, in which the air is preheated or heated for the electrode coating process 1a and finally fed back into the electrode coating system 1.

[0092] Fig. 1a schematically shows an example of a method according to the invention for treating process air from an industrial process for producing lithium-ion batteries. In the method according to Fig. 1a, an electrode coating process S1 takes place, preferably using a solvent or solvent mixture, for example a combination of TEP and EAA (hereinafter referred to as TEP / EAA solvent). The process air is used to dry the wet electrode coating containing TEP / EAA solvent, in particular to expel the solvent from at least one coating layer.

[0093] According to the method according to the invention, the process air A is fed in a main stream 5 to a first condensation step S41. Before the condensation step S41, the process air A is preferably filtered. A filtration step S4a serves to separate the process air A from coarse particles which were created during the electrode coating process S1 and / or entrained or carried along by the flowing process air A. In the first condensation step S41, the process air A is cooled from, for example, approx. 120 °C upon entry into the first condensation step S41, successively down to approx. 15 °C. This separates a first condensate 16 from the process air A, which is fed to a first recovery process S42. In the first condensation step S41, the process air A can be cleaned such that the concentration of TEP / EAA solvent in the process air A typically falls below approx.4000 ppm upon entry into the first condensation step to, for example, approximately 300 ppm upon exit (i.e., reduced by a factor greater than 10). In the recovery process S42, the first condensate 16 is collected and, in addition, preferably treated with a destination and condensate reprocessing process (not shown). The first condensate 16, which contains, for example, TEP / EAA solvent, is converted into a first enriched condensate 16a. If required, the TEP / EAA solvent can also be separated into the different solvent components (TEP and EAA) in the recovery process S42. Preferably, the enriched condensate 16a and / or the solvent components are subsequently fed back into the electrode coating process S1.

[0094] After the process air A in the main stream 5 has been treated in the first condensation step S41, exhaust air B is diverted from the main stream 5 via a first branch S44 into a secondary stream 31, which is then fed to a second condensation step S51. The volume flow diverted into the secondary stream 31 typically corresponds to approximately 10% of the existing volume flow remaining in the main stream 5 after the first branch S44 and is fed to a first further treatment step S45.

[0095] After the first branching S44, the process air A is conditioned in a first further treatment step S45, in particular by first warming or heating the process air A, then optionally supplementing it with air from the environment and then preferably further heating it. In particular, the relative saturation of the process air A is reduced. After the first further treatment step S45, a portion of the process air A is branched off from the main stream 5 in a second branching S44a and added to the exhaust air B led to the second condensation step S51. In particular, the relative saturation of the exhaust air B led to the second condensation step S51 can be reduced overall by adding a portion of process air A treated after the first further treatment step S45, which has a lower relative saturation, to the exhaust air B.The volume flow branched off at the second branching S44a typically corresponds to less than 15%, preferably less than 10%, particularly preferably less than 5% of the existing volume flow remaining in the main stream 5 after the second branching S44a.

[0096] The process air A remaining in the main stream 5 is fed back to the electrode coating process S1 after the second branch S44a. Main stream 5 is also called the recirculation stream or "make-up air."

[0097] After the first branching S44, the exhaust air B is led to the second condensation step S51. The exhaust air B preferably has a temperature of 20 °C upon entering the second condensation step S41. There, the exhaust air B is successively cooled down to, for example, -20 °C, wherein a second condensate 17 is separated from the exhaust air B and fed to a second recovery process S52. In the second condensation step S51, the exhaust air B can be cleaned such that a concentration of TEP / EAA solvent (or other solvents, e.g., NMP, GBL, etc.) in the process air can be reduced from typically approximately 300 ppm upon inlet to typically approximately 50 ppm upon outlet. In the recovery process S52, the second condensate 17 is collected and also treated with a destination and condensate recycling process (not shown).The second condensate 17 is processed into a second enriched condensate 17a, which in particular contains TEP / EAA solvent, in particular separated into the respective solvent components (TEP and EAA) and fed back to the electrode coating process S1.

[0098] After the second condensation step S51, the exhaust air B in the secondary stream 31 is treated in a second treatment step S54. The exhaust air B is first tempered to 20 °C, then filtered, and finally released into the environment via an outlet step S55. The filtering in the second treatment step S54 ensures that the solvent components in the exhaust air B are removed in such a way that the legal emission limits can be met.

[0099] Fig. 2 shows schematically an alternative embodiment for the treatment of exhaust air by means of a concentrator 80 in a device according to the invention, wherein the exhaust air was branched off from the main stream 5 in a first and second branch.

[0100] In contrast to Fig. 1, the bypass duct 31a is connected to an inlet 80i of the downconcentrator 80. The exhaust air B is guided to the downconcentrator 80. The downconcentrator 80 is designed, for example, as an adsorption device, wherein the downconcentrator 80 can be designed or function, for example, as a filter, an electrostatic precipitator, or a sorptive precipitator within the scope of the invention. As indicated in Fig. 2, the exemplary sorptive downconcentrator 80 has an adsorption region 80a, a cooling region 80b, and a desorption region 80c. Located in the downconcentrator 80 is at least one adsorber 80d, which is rotatable / displaceable such that its sections are alternately located in the adsorption region 80a or the desorption region 80c.The adsorption region 80a is arranged between an inlet 80i and an outlet 80ii, so that the section of the adsorber 80d located in the adsorption region 80a adsorbs pollutants, in particular solvents, from the exhaust air B flowing from the inlet 80i to the outlet 80ii. In the cooling region 80b, the section of the adsorber 80d moving into the adsorption region 80a is cooled to enhance the adsorption effect.

[0101] The pollutants adsorbed in the adsorption region 80a can then be desorbed from the adsorber 80d and removed from the removal concentrator 80 by rotating / moving the adsorber 80d in the desorption region 80c. To desorb the adsorbed pollutants from the adsorber 80d, a desorption air C is used, which flows through the desorption region 80c. In this exemplary embodiment, the exhaust air B is used as the desorption air C. This exhaust air B is branched off from the secondary stream 31 by means of a branching device 87 via a desorption air line 31b downstream of the removal concentrator 80 and is subsequently heated to a desorption temperature by means of a desorption air heater 84. As shown in Fig. 2, the exhaust air B first flows through the cooling region 80b of the deconcentrator 80 in order to cool the section of the adsorber 80d moving into the adsorption region 80a, before a part of the exhaust air B is branched off and led to the desorption air heater 84.After being heated in the desorption air heater 84, the desorption air C flows through the desorption region 80c of the deconcentrator 80, whereby the adsorbed pollutants are detached or desorbed from the desorption region 80c of the adsorber 80d. After flowing through the desorption region 80c, the desorption air C is discharged as concentrate air D. The concentrate air D is then guided from the desorption region 80c into the main flow channel 5a via a concentrate air line 31c and preferably to the first condenser 2. The connection point between the concentrate air line 31c and the main flow channel 5a thus serves as an inlet for introducing concentrate air D into the first condenser.

[0102] An activated carbon filter 36 is preferably arranged behind the concentrator 80, with which the exhaust air B is filtered before it is discharged to the outlet 21 into the environment 11.

[0103] Fig. 2a illustrates an example of a process S8 for cleaning exhaust air by means of a single-stage concentration step.

[0104] After a portion of the process air A has been branched off from the main stream 5 in the respective process steps S44, S44a of the first and second branching, the exhaust air B is treated in a concentration step S80 by means of a concentrator 80, whereby pollutants from the exhaust air B are adsorbed and the concentration of the pollutant is reduced.

[0105] The process S8 for cleaning exhaust air B by means of a single-stage concentration step comprises the following process steps:

[0106] S80: The exhaust air B is cleaned by means of a single-stage concentration step, thereby reducing the pollutant concentration.

[0107] S80b: A portion of the exhaust air will first absorb heat energy by means of the cooling area 80b and thereby cool the cooling area 80b of the adsorber 80d, wherein in particular the temperature of the portion of the exhaust air will be increased from approximately 20 to 30 °C to approximately 100 to 140 °C as a result of the heat transfer from the cooling area 80b.

[0108] S82; The exhaust air B is filtered using an activated carbon filter, thereby reducing the pollutant concentration.

[0109] S83: The filtered exhaust air B is discharged into the environment.

[0110] First, the process steps for desorbing a concentrator 80 using a so-called raw gas purification process S8a are explained. In the raw gas purification process S8a, a portion of the exhaust air B is diverted before flowing through the adsorption area 80a to desorb the concentrator.

[0111] Alternatively, a clean gas purification process can also be performed. In the clean gas purification process, a portion of the exhaust air B, which has been treated by the adsorption zone 80a, is diverted for desorption. In this case, after flowing through an adsorption zone 80a of the concentrator 80, the exhaust air B treated by the concentrator 80 can be referred to as the so-called clean gas.

[0112] The raw gas cleaning process S8a comprises the following process steps: S87: A portion of the exhaust air B is diverted from the secondary stream 31 for desorption of the concentrator 80.

[0113] S84: The branched part of the exhaust air B is heated by means of a heating element, according to Fig. 2 in the form of a desorption air heater 84, and is led as desorption gas C to the desorption area S80c.

[0114] S80c: After heating in the previous process step, the desorption air C will desorb the pollutant adsorbed in the adsorber 80d in a desorption step S80c as it flows through the desorption area 80c of the concentrator 80 and will be discharged as concentrate air D.

[0115] S41a: The pollutant-containing concentrate air D is passed after the desorption step S80c for treatment with the first condensation step S41 and mixed with the process air A in the main stream 5 before the process air A is treated in the first condensation step S41.

[0116] After the exhaust air B has been treated as described above by means of the concentrator 80 and a part of it has been diverted in process step S81, the remaining part is filtered in a further process step S82 and then discharged into the environment (S83).

[0117] Fig. 3 shows schematically a further alternative embodiment for the treatment of exhaust air of a device according to the invention for treating the exhaust air branched off from the main stream 5 by means of two concentrators arranged one behind the other.

[0118] The second concentrator 85 is arranged downstream of the first concentrator 81. The operation of the first and second concentrators 81, 85 is analogous to the previously described concentrator 80. Of particular note in this exemplary embodiment is the arrangement of the desorption and concentrate air lines.

[0119] A portion of the exhaust air B is branched off by means of a branching device 87a and guided to the desorption air heater 84a. After entering the desorption concentrator 81, a portion of the exhaust air B passes through the cooling area 81b, the desorption air heater 84a, and the desorption area 81c, before the desorption air C is discharged as concentrate air D from the desorption area 81c via a first concentrate air line 31cc. The further course of the concentrate air line 31cc is analogous to the course of the concentrate air line 31c described in Fig. 2. The concentrate air line 31cc is connected to a connection point on the main flow duct 5a, i.e., to an inlet for introducing concentrate air D into the first condenser 2, whereby concentrate air is directed into the main flow duct 5a and guided to the first condenser 2.

[0120] The operation of the de-concentrators 81, 85 is analogous to the de-concentrator 80 shown in Fig. 2. A portion of the exhaust air B is branched off to the desorption air heater 84aa. The air flow is analogous to the previous example, whereby the branched off portion of the exhaust air B is heated to a desorption temperature by means of the desorption air heater 84aa and is guided as desorption air into a second desorption air line 31bbb to the desorption region 85c. After flowing through the desorption region 85c, the desorption air C is discharged as concentrate air D. The concentrate air D is then guided from the desorption region 85c by means of a second concentrate air line 31ccc for treatment with a concentrate air condenser 86, whereby a pollutant-containing condensate is separated from the concentrate air D and a treated concentrate air D' is generated.

[0121] A further concentrate air line 31ddd is connected to an outlet of the concentrate air condenser 86 and is further connected to an inlet 31e for introducing treated concentrate air D' into the first downconcentrator 81. The inlet 31e is shown as a simple connection point between the further concentrate air line 31ddd and the bypass duct 31a.

[0122] The bypass duct 31a is connected to the second branching device 87b and an inlet 85i of the second concentrator 85. The exhaust air B is guided through the bypass duct 31a to the adsorption region 85a of the second concentrator 85. After flowing through the adsorption region 85a of the second concentrator 85, the pollutant concentration of the exhaust air B (for example, the NMP concentration) is further reduced to below 50 ppm, particularly preferably to below 1 ppm. Ideally, the statutory emission limits can already be met at this point, so that the outlet 21 for discharging exhaust air B into the environment is already arranged downstream of the second concentrator 85. Optionally, an activated carbon filter can also be arranged between the outlet 21 and the second concentrator 85 in order to further reduce the pollutant concentration of the exhaust air B before it is discharged into the environment 11, if necessary.This can be the case, for example, if aging effects occur in the concentrators and the actual concentration performance deviates from the originally intended one.

[0123] As an alternative embodiment, several first condensers 2 are operated in parallel with a respective main flow, wherein the exhaust air flows branched off from the respective main flow are combined into the secondary flow channel 31a. The exhaust air B contained in this secondary flow channel 31a is then guided to the first concentrator 81.

[0124] Fig. 3a illustrates an example. Fig. 3 shows a process S9 for purifying the exhaust air using two consecutive concentration stages and two raw gas purification processes S8b and S8c for desorbing a concentrator.

[0125] After a part of the process air A has been branched off from the main stream 5 in the respective process steps S44, S44a of the first and second branching as shown in Fig. 2a, the exhaust air B is led to the process steps S81 and S81b.

[0126] The process S9 for cleaning the exhaust air B comprises the following process steps:

[0127] S87a: In a process step S87a, desorption air C' is diverted from the secondary stream 31 from a portion of the exhaust air B upstream of the first concentration stage. The proportion of the diverted volume flow in this process step typically corresponds to 15% of the volume flow remaining after diverting.

[0128] As an alternative embodiment, several first condensers are operated in parallel with a respective main stream, wherein the exhaust air streams branched off from the respective main stream are combined into a secondary stream 31. Process step S81 is then carried out from this combined secondary stream 31. S81: The exhaust air B is purified in a first concentration stage by means of the concentrator 81, whereby the pollutant concentration is reduced from approximately 1000 ppm to approximately 50 ppm.

[0129] S85: Exhaust air B is purified in a second concentration stage using the concentrator 85, further reducing the pollutant concentration from approximately 40 ppm to less than 1 ppm. Optionally, exhaust air B could be additionally filtered after the second concentration stage using an activated carbon filter.

[0130] S83: The exhaust air B, which has been cleaned after two concentration stages, is discharged into the environment.

[0131] The raw gas cleaning process S8b for desorbing the first concentrator comprises the following process steps:

[0132] S81 b: Part of the exhaust air B is led to a cooling area of ​​the concentrator 81b, wherein the desorption air C' is heated up to 200 °C, in particular up to 180 °C, preferably to approximately 100 to 140 °C.

[0133] S87a: Desorption air C is diverted from another portion of exhaust air B upstream of the second concentration stage. The proportion of the diverted volume flow in this process step typically corresponds to 15% of the volume flow of exhaust air B, which is concentrated in process step S81.

[0134] S84a: The branched part of the exhaust air B is further heated to a desorption temperature of approximately 180 to 200 °C by means of a desorption air heater and is led as desorption air C to the desorption area 81c.

[0135] S81c: After heating, the desorption air C will desorb the pollutant adsorbed in the adsorber 81d in a desorption step S81c as it flows through the desorption area 81c and is discharged as concentrate air D.

[0136] S41a: The concentrate air D is sent for treatment with the first condensation step S41. Alternatively, in this process step, the concentrate air D could be divided into two partial streams, for example, before each of the partial streams is sent to a separate condensation step.

[0137] The raw gas cleaning process S8c for desorbing the second concentrator comprises the following process steps:

[0138] S85b: Part of the exhaust air B is led to a cooling area of ​​the concentrator 85b.

[0139] S87b: A portion of exhaust air B is diverted for desorption by the concentrator. The diverted volume flow in this process step typically corresponds to 18% of the volume flow of exhaust air B, which is concentrated in process step S85.

[0140] S84aa: The branched part of the exhaust air B is further heated to approximately 200 °C by means of a desorption air heater and fed as desorption air to process step S85c.

[0141] S85c: After heating, the desorption air C will desorb the pollutant adsorbed in the adsorber 85d in a desorption step S85c as it flows through the desorption area 85c and is discharged as concentrate air D.

[0142] S86: The concentrate air D is sent to a condensation step with a

[0143] Concentrate air condenser 86 separates the condensate containing pollutants. Treated concentrate air D' is generated after flowing through concentrate air condenser 86.

[0144] S86a: The concentrate air D' treated with the concentrate air condenser 86 is led to treatment with the first concentration stage (S81) of the concentration step.

[0145] Finally, it should be noted that the concentration steps / stages (S80; S81, S85) or the concentrators (80; 81, 85) of the present invention are not limited to the wheel or disc concentrators, in particular zeolite wheels, schematically illustrated in Figures 2, 2a and 3, 3a. Rather, individual concentration steps / stages or concentrators can also be provided or designed in other configurations known to those skilled in the art, such as designs designed as carousel concentrators, without having a significant influence on the implementation of the invention disclosed here. Carousel concentrators are known, for example, from WO 2020 / 126551 A1 and US 10,682,602 B2, to whose descriptions regarding possible alternative or supplementary designs of concentrators, explicit reference is hereby made.

Claims

Claims: A process for treating process gas (A) from an industrial process (S1) with a main stream (5) and a side stream (31), wherein at least a part of the process gas (A) is treated by the following process steps: a first condensation step (S41) in which a first condensate (16) is separated from the process gas (A); a first diversion (S44) taking place after the first condensation step (S41) in which at least a part of the process gas (A) from the main stream (5) is diverted as exhaust gas (B) into the side stream (31); a first further treatment step (S45) taking place in the main stream (5) after the first diversion (S44) in which at least a part of the process gas (A) is further treated after the first condensation step (S41).A method according to claim 1, wherein the first treatment step (S45) comprises heating and / or pressure reduction, and / or the introduction of gas outside the main stream (5), in particular air from an environment (11), and at least a portion of the process gas (A) is treated by the following process step: recirculation of process gas (A) after the first condensation step (S41) into the industrial process. A method according to claim 1 or 2, wherein at least a portion of the process gas (A) is diverted from the main stream (5) in a second branch (S44a), which occurs after the first branch (S44a), in particular after the first treatment step (S45), and added to the exhaust gas (B), wherein the relative saturation of the exhaust gas (B) diverted in the second branch (S44a) is lower than the relative saturation of the exhaust gas (B) diverted in the first branch (S44). 37 RECTIFIED SHEET (RULE 91 ) ISA / EP A method according to one of the preceding claims, wherein at least a part of the exhaust gas (B) is treated with the following process steps: a. a second condensation step (S51) taking place after the first condensation step (S41), in which a second condensate (17) is separated from the process gas (A), b. a second condensation step (S51) taking place after the second condensation step (S51). Further treatment step (S54) in which at least a portion of the exhaust gas (B) is further treated after the second condensation step (S51), comprising heating and / or pressure reduction and / or filtering; and / or c. a deconcentration step (S80) taking place after the first condensation step (S41) with at least one deconcentration stage for reducing the concentration of a pollutant; and / or d. a filtering (S82) of the exhaust gas (B) taking place after the first condensation step (S41). Method according to one of the preceding claims in which the following process steps for desorbing a deconcentrator (80, 81, 85) are carried out: a. a portion of the exhaust gas (B) is diverted before and / or after the portion of the exhaust gas (B) is deconcentrated in a deconcentration stage (S); b. a heating of the diverted part of the exhaust gas (B) to a desorption gas (C), c.a desorption step (S80c) using the desorption gas (C), wherein the desorption gas (C) flows through a desorption section (81c) of the deconcentrator (80, 81, 85) and takes up at least one adsorbed pollutant, i.e. the desorption gas (C) is discharged as concentrate gas (D, D') after passing through the desorption section (81c), e. the concentrate gas (D, D') is used for a condensation step, in particular for the first condensation step (S41) and / or for. 38 RECTIFIED SHEET (RULE 91 ) ISA / EP a further condensation step, and / or a de-concentration step (S81). A method according to one of the preceding claims, in which the following process steps are carried out: a. a concentrate gas (D) is generated after flowing through the desorption section (81c) of a de-concentrator (80, 81, 85), b. the concentrate gas (D) is treated in a condensation step (S86) and / or a de-concentration step, wherein the treated concentrate gas (D') is i. led to the first condensation step (S41) and / or ii. led to a de-concentration step, in particular to the first stage of the de-concentration step (S86a), and / or iii. divided into at least two partial streams before at least one of the partial streams of the treated concentrate gas (D') is led to a condensation step and / or to a de-concentration step (S81).A method according to claim 5 or 6, wherein a method comprises a reduction step comprising at least two reduction stages (S81, S85) arranged one after the other in the direction of flow of the exhaust gas (B), the reduction stages (S81, S85) each comprising a reduction concentrator (81, 85), wherein a concentrate gas (D') of a reduction stage (S85) arranged downstream of at least one reduction stage (S81) is treated with at least one of the following process steps: a. the concentrate gas (D) is mixed with the concentrate gas (D) of an upstream reduction stage (S81); and / or b. the concentrate gas (D) is condensed in a condensation step (S86) and discharged by means of a further concentrate gas line (31 ddd) after the condensation step (S86); and / or c. The concentrate gas (D) is directed to a reduction stage, in particular to the foremost reduction stage (S81); and / or. 39 RECTIFIED SHEET (RULE 91 ) ISA / EP d. the concentrate gas (D) is fed to the first condensation step (S41). A method according to any one of claims 5 to 7, wherein a method comprises a reduction step comprising at least two reduction stages (S81, S85) arranged one after the other in the direction of flow of the exhaust gas (B), wherein the reduction stages (S81, S85) each have a reduction concentrator (81, 85), wherein a concentrate gas (D) of a reduction stage (S81), which is arranged upstream of a further reduction stage (S85), in the case of three or more reduction stages than the foremost reduction stage, is treated with at least one of the following process steps: a. the concentrate gas (D) is mixed with the concentrate gas (D) of a reduction stage (S85) arranged downstream; and / or b.The concentrate gas (D) is condensed in a condensation step (S86) before being discharged via a further concentrate gas line (31ddd) after the condensation step (S86); and / or c. the concentrate gas (D) is fed to a de-concentration stage, in particular to the foremost de-concentration stage (S81); and / or d. the concentrate gas (D) is fed to the first condensation step (S41).Device for treating process gas (A) from an industrial process (S1), in particular for carrying out a method according to one of the preceding claims, comprising an outlet (4a) for discharge of process gas (A) from an industrial process (S1), a heating element (18, 18a) for heating the process gas (A), an inlet (4b) for introducing process gas (A) into a first condenser (2), which has a first cooling unit (6) for cooling process gas (A), a first branch point (9) for diverting at least a portion of process gas (A) as exhaust gas (B) into a sidestream channel (31a). 40 RECTIFIED SHEET (RULE 91 ) ISA / EP wherein the heating element (6, 6a) is arranged behind the first branch point (9).

10. Device according to claim 9 with a second branch point (9a) by which process gas (A) is diverted into the bypass channel (31a) to reduce the relative saturation of the exhaust gas (B), wherein the first branch point (9) is arranged downstream of the cooling unit (6) and the second branch point (9a) is arranged downstream of the heating element (18).

11. Device according to claims 9 to 10, wherein the bypass channel (31a) for introducing at least a portion of the exhaust gas (B) is connectable to: a. an inlet (4bb) arranged downstream of the first condenser (2) for introducing into a second condenser (3), whereby a second condensate (17) is discharged from the exhaust gas (B); and / or b. an inlet (80i) arranged downstream of the first condenser (2) for introducing into a deconcentrator (80) for reducing the concentration of a pollutant; and / or c. an inlet (36a) arranged downstream of the first condenser (2) for introducing into a filter, in particular an activated carbon filter (36).

12. Device according to one of claims 10 to 11, in particular for carrying out a method according to one of the preceding claims for desorbing a deconcentrator (80, 81, 85) with a branch device (87, 87a, 87b) for removing a part of the exhaust gas (B), wherein the branched part of the exhaust gas (B) is directed to a heating unit (84, 84a, 84aa) in which desorption gas is generated for desorbing the deconcentrator (80, 81, 85).

13. Device according to one of claims 10 to 12 comprising a deconcentrator (80) having at least one adsorption (80a) and one desorption (80c) region, a concentrate gas line (31c) for conveying concentrate gas (D) from the desorption region to an inlet for introducing concentrate gas (B) into the first condenser (2) and / or into a 41 RECTIFIED SHEET (RULE 91 ) ISA / EP Concentrate gas condenser (86) and / or into an adsorption region (80a) of a deconcentrator (80). Device according to one of claims 10 to 13 with at least two deconcentrators (81, 85) arranged one behind the other with respect to the flow direction of the exhaust gas (B), each having at least one adsorption (81a, 85a) and one desorption region (81c, 85c), a second concentrate gas line (31ccc) for removing concentrate gas (D) from the desorption region (85c) of a deconcentrator (85) arranged downstream, wherein the second concentrate gas line (31ccc) for introducing the concentrate gas (D) with: a. an inlet (81i, 85i) for introducing it into an adsorption region (81a, 85a) of a deconcentrator (81, 85); and / or b. a first concentrate gas line (31 cc) of an upstream deconcentrator (81) for mixing with its concentrate gas (D); and / or c. the inlet (4b) for introducing into the first condenser (2) and / or d.a device according to one of claims 13 or 14, wherein a further concentrate gas line (31 ddd) for introducing a concentrate gas (D') treated in a condenser (86) and / or deconcentrator has an inlet for introducing it into the first condensation step (S2) and / or an inlet (31 e) for introducing it into a deconcentrator (81), and / or a divider, wherein the treated concentrate gas is divided into at least two partial streams before at least one of the partial streams of the treated concentrate gas (D') is guided to an inlet (4b, 4bb) for introducing it into a condenser (2, 3) and / or into a deconcentrator (81 i, 85i). 42 RECTIFIED SHEET (RULE 91 ) ISA / EP Device according to any one of claims 9 to 15 with at least two deconcentrators (81, 85) arranged one behind the other with respect to the flow direction of the exhaust gas (B), each having at least one adsorption (81a, 85a) and one desorption region (81c, 85c), a first concentrate gas line (31 cc) for removing concentrate gas (D) from the desorption region (81c) of an upstream deconcentrator (81), in the case of at least three deconcentrators of the foremost deconcentrator, wherein the first concentrate gas line (31 cc) for introducing the concentrate gas (D) with: a. an inlet for introducing into the adsorption region (81a, 85a) of a deconcentrator (81, 85); and / or b. an inlet for introducing into a concentrate gas condenser (86); and / or c. the second concentrate gas line (31 ccc) of a downstream deconcentrator (85) for mixing with its concentrate gas (D); and / or d.the inlet (4b) can be connected for introduction into the first capacitor (2). Use of the method according to one of claims 1 to 8 or the device according to one of claims 9 to 16 for treating a circulating process fluid, in particular circulating or recirculated air of a dryer, for treating process air (A) of a dryer, in particular from the process air (A) of a manufacturing plant for the production of electrodes of a battery. 43 RECTIFIED SHEET (RULE 91 ) ISA / EP

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