Method and apparatus for separating a substance from a carrier gas stream by partial condensation

Abstract

A method for separating a gaseous or vaporous substance from a carrier gas stream by partial condensation, in which a carrier gas loaded with at least one substance to be condensed is guided through a flow path (20) extending in the housing (2, 102, 202, 302) of a condenser from a carrier gas inlet (7, 107, 207, 307) to a carrier gas outlet (8, 108, 208, 308), within which it is brought into indirect thermal contact with a heat transfer medium at a first heat exchanger surface and is thereby cooled to a temperature below the dew point temperature of the substance to be condensed, wherein the substance at least partially condenses on the heat exchanger surface in the form of liquid condensate, which is subsequently collected in a condensate bath (22) and discharged, wherein The carrier gas, after contact with the first heat exchanger surface, passes through an evaporation zone (23, 124) in the flow path (20) in which a temperature prevails that is higher than the dew point temperature of the substance to be condensed, and the carrier gas is subsequently cooled at a second heat exchanger surface in the flow path (20) in indirect thermal contact with a heat transfer medium to a temperature below the dew point temperature of the substance to be condensed. characterized by that at least a partial flow of the heat transfer medium used at the first and / or the second heat exchanger surface is brought into thermal contact with the collected condensate in the condensate bath (22) and is subsequently supplied to the evaporation heat exchanger surface (18b, 118b, 226b, 326b) for indirect heat exchange with the carrier gas in the evaporation area (23, 124).

Description

[0001] The invention relates to a method for separating a gaseous or vaporous substance from a carrier gas stream by partial condensation according to the preamble of claim 1. The invention further relates to a corresponding device.

[0002] Such processes and devices are known. They are characterized by the fact that a carrier gas loaded with a substance to be separated is cooled to a temperature below the dew point of the substance, and the substance that condenses during this process is subsequently removed from the carrier gas stream. The carrier gas, which does not condense during the process itself, is, for example, air, nitrogen, hydrogen, a noble gas, or a mixture of two or more of these gases. Frequently, the carrier gas is a gas stream from an industrial process (process gas) loaded with the gases or vapors to be separated. In the following, the terms "process gas" and "carrier gas" are used synonymously. The carrier gas stream loaded with substances to be separated is also referred to as the "carrier gas stream to be treated."The process gas stream to be treated and the carrier gas stream that is at least partially freed from the substances to be separated are referred to as the "treated carrier gas stream" or "treated process gas stream".

[0003] The gases or vapors to be separated from the carrier gas by condensation are primarily VOCs (volatile organic compounds) or other substances whose condensation temperature is higher than that of the carrier gas, such as water. It is irrelevant whether the substances to be separated are liquid or gaseous under ambient conditions. Furthermore, a carrier gas stream to be treated can also be loaded with several substances, not all of which are to be separated, or which are to be separated in successive process steps.

[0004] Prior art condensation processes utilize one or more devices called condensers. A condenser typically has a well-insulated housing through which the carrier gas stream to be treated is guided along a flow path and brought into indirect contact with a cold heat transfer medium at heat exchanger surfaces. The carrier gas is thereby cooled to a temperature below the dew point of the gaseous or vaporous substance to be separated from the process gas. The substance condenses or freezes, at least partially, and the resulting condensate can be separated from the gas stream. The heat transfer medium is, for example, a cryogenic cooling medium such as liquid nitrogen. Such condensation devices are widely used and are described, for example, in EP 1 743 688 A1, EP 0 275 472 A2, EP 0 988 879 A1, and DE 19 645 487 C1.

[0005] From DE 10 2017 007 031 B3, a device and a method for separating vapors from a gas stream are known, in which a process gas stream successively passes through two heat exchangers, where it is brought into thermal contact with a cooling medium. In the second heat exchanger, the process gas stream is also heated at a surface to re-evaporate aerosols that have formed during the process. The re-evaporated components then largely condense on the heat exchanger surfaces of the second heat exchanger.

[0006] A problematic aspect of many known condensation processes is the formation of aerosols. When a carrier gas stream laden with a substance encounters a surface whose temperature is significantly below the dew point temperature of the substance, aerosols are formed in the surrounding area. These aerosols contain the substance to be condensed and cannot be separated from the carrier gas stream within the condensers themselves. This leads to a higher residual loading of the treated carrier gas streams than would be expected based on the carrier gas temperature reached in the condenser.

[0007] To avoid or reduce aerosol formation, condensation processes are designed to minimize temperature differences between the carrier gas and the cooling surfaces in the condenser's flow path. However, this either leads to very large and complex equipment or results in reduced process efficiency.

[0008] Furthermore, a method and apparatus for low-aerosol partial condensation are known from EP 1 602 401 A2. In this method, a carrier gas stream to be treated is passed through two condensers connected in series, in each of which it is brought into indirect thermal contact with a cryogenic heat transfer medium. A heating device is arranged between the condensers, by means of which the carrier gas stream is heated to a temperature above the condensation temperature of a substance to be removed from the carrier gas. This causes the aerosols that have formed in the first condenser to evaporate. In the subsequent condenser, cooling occurs again below the dew point of the substance in the carrier gas, whereby at least a significant portion of the substance to be removed can be separated from the former aerosols. The aerosol content in the treated carrier gas stream is thus drastically minimized.The method described there has proven effective, but is comparatively complex in terms of setup and maintenance.

[0009] The object of the present invention is therefore to provide a method for separating vaporous or gaseous substances from a carrier gas stream by partial condensation, in which the loading of the treated carrier gas stream with aerosols is reduced compared to condensation methods according to the prior art and this can be achieved with comparatively simple means.

[0010] This problem is solved by a method having the features of claim 1 and by a device having the features of claim 8.

[0011] According to the invention, the carrier gas flows through a flow path within the housing of a condenser, where it is successively brought into indirect thermal contact with a heat transfer medium, for example, liquid or cold gaseous nitrogen, at at least two heat exchanger surfaces. At a first heat exchanger surface, it is cooled to a first temperature T1 below the dew point temperature TT1 of the substance to be condensed in the region of the first heat exchanger surface. At least a first portion of the substance contained in the carrier gas stream condenses and is discharged as liquid condensate, for example, and collected in a condensate container. Subsequently, the carrier gas passes through an evaporation zone in the flow path, in which a temperature T2 is maintained that is above the dew point temperature TT2 of the substance in this zone. During this phase, the aerosols present in the carrier gas stream evaporate, at least partially.At a second heat exchanger surface located downstream of the evaporation zone in the flow path, the carrier gas is cooled again, this time to a third temperature T3 below the dew point temperature TT3 of the substance to be condensed in the area of ​​the second heat exchanger surface. As a result, a significant portion of the substance from the previously evaporated aerosols condenses as liquid condensate at the second heat exchanger surface and is also removed. Therefore, T3 generally applies. <T1<T2, d.h. die Temperatur des Trägergases an der zweiten Wärmetauscherfläche ist niedriger als die Temperatur des Trägergases an der ersten Wärmetauscherfläche. Die Temperatur der Wärmeträgermedien im ersten und zweiten Wärmetauscher kann dabei auf gleicher Höhe liegen oder unterschiedlich sein; wesentlich für die Erfindung ist jedoch, das Trägergas im Bereich beider Wärmetauscher jeweils auf eine Temperatur unterhalb der jeweiligen Taupunkttemperatur gebracht wird.

[0012] The arrangement of the first and second heat exchanger surfaces and the evaporation zone within the same condenser housing results in the carrier gas flowing through being cooled and reheated very rapidly over a comparatively short distance. Therefore, aerosol droplets that form during the condensation of the substance in the vicinity of the first heat exchanger have very little time to coagulate into larger and more stable droplets; due to their relatively small diameter, they evaporate very quickly in the evaporation zone.

[0013] Advantageously, the process can also be carried out in multiple stages by repeatedly cooling the carrier gas at a first heat exchanger surface or group of first heat exchanger surfaces as it passes through the flow path, then heating it in an evaporation zone, and cooling it again at a second heat exchanger surface or group of second heat exchanger surfaces. The flow path can also be selected such that a second heat exchanger surface (or group of second heat exchanger surfaces) arranged downstream of an evaporation zone simultaneously functions as the first heat exchanger surface (or group of first heat exchanger surfaces) for a subsequent evaporation zone.Such a design can be implemented in a particularly simple manner, for example, by forcing the carrier gas in the condenser housing into a meandering path using conventional flow guide vanes. This path repeatedly flows around several straight-line arranged tube bundles serving as first and / or second heat exchanger surfaces, which are cooled by the heat transfer media flowing through them. Evaporation zones are provided between two such heat exchanger surfaces or between two groups of heat exchanger surfaces. These zones are equipped with means for heating the carrier gas; for example, they consist of another heat exchanger, such as a tube bundle through which a correspondingly warmer heat transfer medium flows.In a multi-stage process, even large temperature differences between the heat transfer media at the heat exchanger surfaces and the carrier gas can be tolerated, since the aerosols that initially form in relatively high quantities are at least largely eliminated in the subsequent process stages. This increases the efficiency of the process and enables a compact design for the corresponding condensation device.

[0014] The temperature of the carrier gas in the evaporation zone can be controlled, in particular, by means of an electric heating device and / or by heat from a radiation source. However, it is especially preferred that the carrier gas in the evaporation zone is heated by means of a heat exchanger surface (evaporation heat exchanger surface) where the carrier gas is brought into indirect thermal contact with a heat transfer medium whose temperature is above the dew point temperature of the substance to be condensed in the carrier gas. Furthermore, it is advantageous if the temperature in the evaporation zone is controlled by suitable means as a function of measured parameters, such as the residual charge of the treated carrier gas.

[0015] The heat transfer medium used at such an evaporative heat exchanger surface can be a different medium or the same medium used at the first and / or second heat exchanger surface. To heat the carrier gas in the evaporation zone at the evaporative heat exchanger surface, it must be heated to a suitable temperature.

[0016] The temperature control of a heat transfer medium used on the evaporative heat exchanger surface can be achieved, for example, by means of an electric or otherwise operated heating device.

[0017] According to the invention, at least a partial flow of the heat transfer medium used at the first and / or second heat exchanger surface is brought into thermal contact with the collected condensate after passing through this heat exchanger surface(s) and is then fed to the evaporative heat exchanger surface. The condensate is at a temperature that is naturally above the required dew point temperature. For example, the condensate collected at the first and / or the second and / or a subsequent heat exchanger surface is temporarily stored in a condensate tank, which can be arranged inside or outside the condenser housing. Preferably, a heat exchanger is arranged in this condensate tank, in which the heat transfer medium discharged from the first and / or second heat exchanger surface is brought into indirect thermal contact with the condensate.

[0018] This design is particularly advantageous when the inventive method is used in a device where the condensate is collected within the condenser housing, for example, in a sump of the housing, forming a condensate bath where there is no flow separation from the carrier gas stream. In such arrangements, especially with low-boiling substances, the problem arises that the condensate, due to thermal fluctuations or external heat input, re-evaporates completely or partially and returns to the carrier gas. The thermal contact of the heat transfer medium from the first and / or the second heat exchanger with the condensate in the condensate bath reduces its temperature, thereby at least reducing the probability of re-evaporation or preventing it entirely.In this way, active cooling of the condensate by means of a cooling device can be dispensed with, or at least such a device can be designed to be smaller.

[0019] In some cases, however, it may also prove advantageous to heat the condensate and / or the heat transfer medium fed to the heat exchanger in the condensate bath, for example by means of an electric heating device. Heating prevents excessive cooling or even freezing of the condensate, especially when a large flow rate of heat transfer medium is passed through the heat exchanger in the condensate tank.

[0020] The heat transfer media used at the first, second, and / or any subsequent heat exchanger surfaces can be derived entirely or partially from different sources; for example, they can be media of different composition or maintained at different temperatures. Preferably, however, the cooling medium used at the first and second heat exchanger surfaces originates from a common source, such as a liquid nitrogen tank. If the evaporation zone is heated by a heat transfer medium at an evaporation heat exchanger surface, it is advantageous, particularly for economic reasons, to use the same heat transfer medium, such as nitrogen, for this purpose as well, originating from the same source as the other heat transfer media.

[0021] A particularly advantageous process is one in which a liquefied gas, such as liquid nitrogen (LIN), liquid oxygen (LOX), or liquefied natural gas (LNG), is used as the heat transfer medium, which at least partially evaporates at the first and / or second heat exchanger surface through thermal contact with the carrier gas. This also allows the enthalpy of vaporization of the heat transfer medium to be used for cooling the carrier gas.

[0022] A cryogenic heat transfer medium, such as liquid nitrogen (LIN) or another cryogenically liquefied gas, is preferably used as the heat transfer medium at the first and / or second heat exchanger surface. However, other liquid or gaseous heat transfer media can also be used, provided they can be heated to a temperature suitable for condensing the substances to be separated in the carrier gas stream, such as brine, cooling water, or thermal oil.

[0023] Since the treated carrier gas, after thermal contact with the heat transfer medium at the second or subsequent heat exchanger surface, is sometimes at a very low temperature, it is often advantageous to bring at least a partial flow of the treated carrier gas into thermal contact with the untreated carrier gas in order to utilize any remaining residual cooling for the untreated carrier gas. This is achieved, for example, by means of an additional heat exchanger surface (recuperator), such as a tube bundle, which is arranged inside or outside the condenser housing and at which at least a partial flow of the treated carrier gas is brought into indirect thermal contact with the untreated carrier gas flow.

[0024] Furthermore, the inventive method also enables the treatment of carrier gas streams loaded with several substances, not all of which are to be separated, or which are to be separated simultaneously or in successive steps in the manner described above.

[0025] The object of the invention is also solved by a device with the features of claim 8.

[0026] A device according to the invention thus comprises a condenser housing through which a flow path extends from a process gas inlet to a process gas outlet, through which a carrier gas loaded with a substance to be condensed is guided during operation of the device. The flow path is not necessarily a straight path; rather, the flow path can also be designed such that the carrier gas is deflected once or several times within the housing and / or forced into a meandering path by means of suitable aids, such as flow guides. In this flow path, two or more heat exchanger surfaces are arranged one after the other for cooling the carrier gas to a temperature below the dew point temperature of a substance to be condensed contained in the carrier gas. These heat exchanger surfaces may each be, for example, a tube, a tube bundle, a cooling coil, or a section thereof.Between at least two of the heat exchanger surfaces – referred to here as the first and second heat exchanger surfaces – an evaporation zone is provided in which the carrier gas can be heated by suitable means to a temperature above the dew point temperature of the substance to be condensed in this evaporation zone. The means for heating the carrier gas in the evaporation zone include, for example, an electric heater or a heat exchanger through which a suitably heated heat transfer medium flows (evaporative heat exchanger). The device is also equipped with a system for collecting and draining liquid condensate.This preferably has one or more condensate tanks assigned to one or more heat exchangers, in which the condensate collected at the respective heat exchanger is stored at least temporarily; the condensate tank(s) may be arranged inside or outside the housing; the condensate tank may in particular be the sump of the condenser housing.

[0027] In the device according to the invention, the carrier gas is successively brought into indirect thermal contact with a heat transfer medium at the two heat exchanger surfaces and thereby cooled to a temperature below the respective dew point temperature of the substance to be condensed. The heating of the carrier gas in the evaporation zone located between the two heat exchanger surfaces raises the carrier gas temperature above the dew point temperature of the substance to be condensed. This causes aerosols containing the substance to be condensed, which are present in the carrier gas, to evaporate. The substance, now in gaseous form, condenses again upon cooling of the carrier gas at the second, or a subsequent, heat exchanger surface and is then at least partially discharged in the form of liquid condensate.

[0028] The device according to the invention is characterized by a compact and comparatively simple design and is suitable for effectively reducing aerosols in the treated carrier gas. The device is therefore particularly suitable for carrying out the method according to the invention.

[0029] In an advantageous embodiment of the device according to the invention, more than two heat exchanger surfaces for cooling the carrier gas are arranged one after the other in the flow path of the carrier gas, and the carrier gas flows over these surfaces sequentially. Evaporation zones for temporarily heating the carrier gas are provided at least between some of the heat exchanger surfaces. For example, a group consisting of two or more first heat exchanger surfaces arranged one after the other in the flow path can be arranged upstream of an evaporation zone equipped with means for heating the carrier gas, and / or a group consisting of two or more second heat exchanger surfaces arranged one after the other in the flow path can be arranged downstream of such an evaporation zone, wherein cooling of the previously cooled carrier gas takes place at the heat exchanger surfaces and heating in the evaporation zone.Similarly, a sequence of two or more evaporation zones with means for heating the carrier gas can be provided in the flow path. Upstream of each of these zones (viewed in the direction of the carrier gas flow), a first heat exchanger surface or a group of first heat exchanger surfaces is provided, and downstream of each zone, a second heat exchanger surface or a group of second heat exchanger surfaces is provided. The second heat exchanger surface or group of second heat exchanger surfaces can also be arranged directly upstream of an evaporation zone, so that it functions as the first heat exchanger or group of first heat exchangers with respect to that evaporation zone.In general, the first heat exchanger surface(s) shall be understood to be one or more such surfaces located in the flow path of the carrier gas upstream of an evaporation zone, and the second heat exchanger surface(s) shall be one or more such surfaces located in the flow path downstream of an evaporation zone.

[0030] Advantageously, the first heat exchanger and / or the second heat exchanger is designed as a shell-and-tube heat exchanger through which a heat transfer medium flows. The first heat exchanger surface and / or the second heat exchanger surface and / or, if applicable, one or more further heat exchanger surfaces are therefore each a tube bundle or a section of a tube bundle through which a heat transfer medium flows. The same or different heat transfer media can be used at both heat exchanger surfaces.

[0031] A particularly advantageous embodiment of the device according to the invention provides that the flow path of the carrier gas is meandering around tube bundles of the first and second heat exchangers, which are arranged parallel to each other and function as heat exchanger surfaces. A meandering flow path can be realized in a conventional manner, for example, by suitable flow guide plates, so-called "baffles," arranged within the condenser housing. With each change in the direction of the flow path, sections of the respective tube bundles are exposed to the carrier gas, resulting in a cooling of the carrier gas. Evaporation zones are provided between at least some of these sections, in which means for heating the carrier gas are arranged. Thus, as the carrier gas passes through the flow path, it is repeatedly cooled, heated, and cooled again in succession.With such a multi-stage arrangement, aerosols consisting of the substance and present in the carrier gas can be almost completely eliminated.

[0032] Furthermore, the tube bundles of all the aforementioned heat exchangers can also be U-shaped or connected to deflection chambers located in a headspace of the condenser housing in order to increase the flow path of the respective heat transfer medium in the condenser housing and the contact area with the carrier gas.

[0033] According to the invention, the means for heating the carrier gas in the evaporation zone comprise an evaporation heat exchanger equipped with an inlet and outlet for a heat transfer medium and an evaporation heat exchanger surface. Structurally, this is actually a third heat exchanger surface, which is arranged in the flow path between the other two heat exchanger surfaces, but operates at a higher temperature compared to them.

[0034] The supply line for the heat transfer medium of the evaporative heat exchanger is connected to the outlet for the heat transfer medium of the first and / or second heat exchanger, with means for heating the heat transfer medium being provided in the outlet for the heat transfer medium of the first and / or second heat exchanger, upstream of the evaporative heat exchanger. The first and / or second heat exchanger and the evaporative heat exchanger are therefore operated with the same heat transfer medium, which, however, is heated after passing through the first and / or second heat exchanger and before passing through the evaporative heat exchanger.

[0035] The aforementioned means for heating the heat transfer medium also include a condensate bath for the liquid condensate separated in the device and a heat exchanger surface arranged in the condensate bath, which is preferably also a tube bundle or a section thereof. At the heat exchanger surface, the heat transfer medium flowing from the first and / or second heat exchanger can be brought into thermal contact with the condensed substance before being fed to the evaporative heat exchanger. The condensate bath is preferably contained within the condenser housing, for example in a collection tank or in the sump of the condenser housing.

[0036] Preferably, the condensate bath includes means for tempering the condensate. Depending on the specific application, this can be a heating device and / or a cooling device.

[0037] A further advantageous embodiment of the invention provides that – viewed in the direction of flow of the carrier gas – a further heat exchanger, referred to here as a cryogenic heat exchanger, is arranged downstream of the second heat exchanger. At the cryogenic heat exchanger, the process gas is further cooled, preferably to a temperature lower than the temperature of the process gas at the second heat exchanger. This at least largely eliminates any remaining residual charge of substance to be condensed. Since aerosols are present in the carrier gas only to a very small extent downstream of the second heat exchanger (or a subsequent heat exchanger), no evaporation zone is required in the region of the cryogenic heat exchanger. The cryogenic heat exchanger is preferably designed as a shell-and-tube heat exchanger, in which the carrier gas is brought into thermal contact with a heat transfer medium supplied as a liquefied gas, which thereby evaporates.The evaporated heat transfer medium is subsequently used, for example, as a gaseous heat transfer medium in the first and / or the second heat exchanger and / or the evaporative heat exchanger.

[0038] A further advantageous embodiment of the invention provides that the heat exchanger surfaces of the first and / or second heat exchanger and the evaporative heat exchanger are designed as tube bundles that run concentrically to each other at least in a section of the condenser housing, wherein the tube bundles of the first and / or the second heat exchanger are arranged radially, at least partially, within the tube bundle of the evaporative heat exchanger. In this case, the evaporative heat exchanger, through which a relatively warmer heat transfer medium flows, acts as a cooling shield to protect the first and / or the second heat exchanger.

[0039] The drawings are intended to illustrate exemplary embodiments of the invention in more detail. The schematic views show: Fig. 1: A device according to the invention in a first embodiment in a longitudinal section, Fig. 2: A device according to the invention in a second embodiment in a longitudinal section, Fig. 3: A device according to the invention in a third embodiment in a longitudinal section and Fig. 4: A device according to the invention in a fourth embodiment in a longitudinal section.

[0040] In the embodiments of the invention shown below, identical or similarly acting components are identified by the same reference numerals.

[0041] The in Fig. The device 1 shown in Figure 1 for separating a gaseous or vaporous substance from a carrier gas stream by partial condensation has a condenser housing 2 equipped with thermally insulating walls. The condenser housing 2 comprises a cylindrical central section 3, a head chamber 5 separated from it by a tube sheet 4, and a sump 6. A carrier gas inlet 7 opens into the central section 3 at a lower geodetic position, and a carrier gas outlet 8 opens into the upper geodetic position. The head chamber 5 is divided by a vertical partition 9 into two fluidically separated sub-chambers 11 and 12. A supply line 13 for a liquid or gaseous heat transfer medium opens into sub-chamber 12, while an outlet 14 for heat transfer medium opens into sub-chamber 11.The sump 6, designed to receive liquid condensate, is equipped with an overflow 15, to which a gas barrier 16 is connected to prevent unwanted gas passage, for example a siphon or similar.

[0042] The sub-chambers 11, 12 of the head chamber 5 are interconnected via two U-shaped tube bundles 17, 18. In the embodiments shown here, these bundles are only indicated by individual tubes for clarity, but in reality, they consist of a plurality of parallel tubes. Each tube bundle 17, 18 has vertical tube bundle sections 17a, 17b; 18a, 18b, which are interconnected at their lower ends via a curved tube bundle section 17c, 18c or by tube sheets (not shown here). The tube bundles 17, 18 extend to different depths into the condenser housing 2. While tube bundle 17 does not extend deeper than a height just above the overflow 15, tube bundle 18 extends deep into the sump 6 below the level of the overflow 15. Furthermore, in the central section 3 of the capacitor housing 2 there are a plurality of flow guide vanes 19 (so-called“Baffles”) are arranged which force a gas flowing from the carrier gas inlet 7 to the carrier gas outlet 8 within the central section 3 into a meandering flow path 20 (indicated here by a dashed line).

[0043] During operation of the device 1, a carrier gas (process gas) loaded with a substance to be condensed flows into the condenser housing 2 via the carrier gas inlet 7 and exits it via the carrier gas outlet 8. The gas barrier 16 prevents process gas from flowing out via the overflow 15. In the central section 3, the flow path 20 of the process gas meanders, with the process gas coming into contact with the tube bundle sections 18b, 17b, 17a, 18a (in the case of a flow direction from left to right) or 18a, 17a, 17b, 18b (in the case of a flow direction from right to left) after each change in direction. At the same time, a heat transfer medium, which is cold compared to the process gas, is supplied via the sub-chamber 12 of the head chamber 5, from which it flows into the tube bundles 17, 18.If a liquefied gas, such as liquid nitrogen, is used as the heat transfer medium, the flow of the heat transfer medium through the tube bundles 17, 18 is preferably adjusted so that the heat transfer medium evaporates through thermal contact with the process gas within the tube bundle sections 17a, 18a. The heat transfer medium flows parallel through the tube bundles 17, 18 to the sub-chamber 11 and is discharged via the outlet 14.

[0044] Due to the thermal contact of the process gas with the heat transfer medium in the tube bundles 17, 18, the process gas is cooled at least at some points in the flow path 20 to a temperature below the dew point of a gaseous or vaporous substance contained in the process gas (hereinafter also referred to as the "substance to be condensed"). A liquid condensate forms on the surfaces of the tube bundles 17, 18, which subsequently collects in the sump 6 to form a condensate bath 22. The condensate bath 22 rises to a maximum level 21, which is determined by the position of the overflow 15. As soon as this level is reached, any further condensate flowing in is discharged via the overflow 15 and disposed of or further utilized.

[0045] Since the curved tube bundle section 18c of the tube bundle 18 runs below level 21, the heat transfer medium flowing through the tube bundle 18 comes into thermal contact with the liquid condensate bath 22 and is thereby heated; simultaneously, the condensate bath 22 is cooled in the sump 6. The heat transfer medium flowing through tube bundle section 18b is therefore at a higher temperature than that flowing through tube bundle sections 17a, 17b, and 18a.

[0046] In a right-to-left section of the flow path 20, the process gas successively flows around the tube bundle sections 18a, 17a, and 17b. Due to the low temperatures prevailing in the tube bundle sections 18a, 17a, and 17b, the process gas is cooled to a temperature below the dew point of the substance being condensed. In addition to the liquid condensate, undesirable aerosols containing the substance being condensed are also formed and carried along by the carrier gas stream. The flow path 20 of the process gas then crosses the tube bundle section 18b twice in succession. This section is at a comparatively higher temperature due to its previous thermal contact with the condensate in the sump 6. In an evaporation zone 23 around the tube bundle section 18b (indicated here by a gray area), the process gas is thereby heated above the dew point temperature of the substance being condensed.The aerosols that formed previously evaporate, at least to a large extent, and the substance that condenses back into gaseous form again with the process gas to create a homogeneous gas mixture. Subsequently, the process gas flows again around the tube bundle sections 17b, 17a, and 18a (but in a different loop of the meandering flow path), where it is cooled once more to a temperature below the dew point temperature of the substance, and the substance condenses again on the surface of the tube bundle sections 17a, 17b, and 18a. A large portion of the substance contained in the previously evaporated aerosols can thus be separated from the process gas and added to the condensate in sump 6.

[0047] An optional heating device 24, for example an electrically operated one, allows the condensate to be heated as needed, in particular to prevent the condensate from cooling down too much or freezing due to thermal contact with the heat transfer medium at the tube bundle section 18c. Alternatively or additionally, but not shown here, the heat transfer medium can also be heated before passing through the tube bundle section 18c, or warmer heat transfer medium can be added to the heat transfer medium in the tube bundle section 18c. Instead of or in addition to the heating device 24, a cooling device can also be provided to cool the condensate, for example, in the case of external heat input and / or only minimal cooling by the heat transfer medium, to prevent the condensate from re-evaporating.

[0048] The exemplary embodiment according to Fig. In contrast to the previously described embodiment, version 2 is characterized by a longer flow path of the process gas and thus by improved utilization of the coldness of the heat transfer medium.

[0049] Similar to device 1, the one in Fig. The device 101 shown in Figure 2 comprises a vertically arranged, thermally well-insulated condenser housing 102. The condenser housing 102 is equipped with a central section 103, a head section 105 fluidically separated from it by a tube sheet 104, and a sump 106. In an upper region of the central section 103, i.e., adjacent to the tube sheet 104, a carrier gas inlet 107 and a carrier gas outlet 108 open into it. The head section 105 is divided by a vertical partition 109 into two fluidically separated sub-chambers 111 and 112, with a supply line 113 for a heat transfer medium opening into sub-chamber 112 and an outlet 114 for a heat transfer medium opening into sub-chamber 111. The sump 106 is equipped with an overflow 115 and a gas barrier 116.

[0050] The sub-chambers 111, 112 of the head chamber 105 are interconnected via two U-shaped tube bundles 117, 118, which are only indicated here by individual tubes. The tube bundles 117, 118 each have vertical tube bundle sections 117a, 117b; 118a, 118b, which are interconnected at their lower ends via a curved tube bundle section 117c, 118c (as shown here) or by tube sheets. The tube bundles 117, 118 extend to different depths into the condenser housing 102; while tube bundle 117 does not extend deeper than a height just above the overflow 115, tube bundle 118 extends deep into the sump 106 below the height of the overflow 115.

[0051] In contrast to device 1, the central section 103 of the condenser housing 103 is divided by a partition 119 into two sections 120 and 121, which are partially separated from each other in terms of flow characteristics. The partition 119 extends vertically from the tube sheet 104 down to just above the sump 106 and forces a downward flow path for the process gas supplied via the carrier gas inlet 107 in section 120, and an upward flow path in section 121, i.e., in each case in counterflow to the heat exchanger medium flowing from the inlet 113 to the outlet 114 through the tube bundles 117 and 118. Furthermore, flow guide plates 122 are provided in both sections 120 and 121, which force a meandering path for the process gas.

[0052] Section 120 serves in particular to cool the process gas to a temperature below the dew point temperature of the substance being condensed and to remove any aerosols that have formed in the process. For this purpose, the process gas in section 120 flows alternately around the tube bundle sections 117b and 118b of the tube bundles 117 and 118. Upon contact with the heat exchanger medium in tube bundle section 117b, the process gas is cooled to a temperature below the dew point temperature of the substance being condensed. The liquid condensate that forms on the surface of tube bundle section 117b flows over the flow guide plates 122 to the sump 106 and collects there to form a condensate bath 123.

[0053] The heat exchanger medium of the tube bundle 118, which is immersed in the condensate bath 123 in tube bundle section 118c and heated there in thermal contact with the condensate, is at a higher temperature in tube bundle section 118b than the heat transfer medium in tube bundle section 117b. Therefore, the process gas, which was previously cooled in tube bundle section 117b, is heated upon thermal contact with the heat transfer medium in tube bundle section 118b to a temperature above the dew point temperature of the substance to be condensed. Heat transfer occurs through contact of the process gas with tube bundle section 118b and / or through thermal radiation emanating from tube bundle section 118b. In this way, an evaporation zone 124 exists radially around the tubes of tube bundle section 118b, in which aerosols containing the substance to be condensed, which were formed during the previous cooling of the process gas, evaporate.The substance, which thus reverts to gaseous form, condenses at least partially in liquid form upon subsequent renewed contact with the tube bundle section 117b.

[0054] The process gas flows from section 120 into section 121 of the central section 103. No further heating occurs in this area; instead, the process gas is continuously cooled to a low temperature in thermal contact with the tube bundle sections 117a and 118a, which function as cryogenic heat exchangers. If a liquefied gas is used as the heat transfer medium, the tube bundle sections 117a and 118a also preferably serve to vaporize the liquid heat transfer medium supplied via inlet 113.

[0055] The in Fig. 3 shown embodiment of a device 201 according to the invention has a condenser housing 202 which is also arranged vertically and provided with thermal insulation, and which is divided into a cylindrical central section 203, a head section 205 which is fluidically separated from this by a tube sheet 204 and a sump 206.

[0056] A carrier gas inlet 207 and a carrier gas outlet 208 open into an upper section of the central section 203. In this embodiment, the headspace 205 is divided by two vertical partitions 209, 210 into three fluidically separated sub-chambers 211a, 211b, 212, with a supply line 213 for a heat transfer medium opening into sub-chamber 212 and an outlet line 214 for a heat transfer medium opening into sub-chamber 211a. Sub-chamber 211b has no connection to the outside of the housing 202. The sump 206 is equipped – as in the preceding embodiments – with an overflow 215 and a gas barrier 216.

[0057] A partition 218, which extends within the central section 203 from the tube sheet 204 to just above the sump 206 and a condensate bath 219 present in the sump 206 during the operation of the device 201, divides the central section 203 into two functional sections 220, 221, wherein section 220 serves to remove the aerosols from the process gas, while in section 221, in which only a few aerosols are still present in the process gas, any remaining residual load in the process gas is at least largely eliminated.

[0058] A tube bundle 222 extends through section 221, connecting the two sub-chambers 212 and 211b in terms of fluid flow. The tube bundle 222 comprises two tube bundle sections 222a and 222b that are essentially perpendicular and parallel to each other, as well as a tube sheet 223 connecting them at their end opposite the tube sheet 204. The tube sheet 223 is suspended freely from the tube bundle sections 222a and 222b and is located above the condensate bath 219. As an alternative to the suspended tube sheet 223 shown here, a U-shaped tube bundle section (similar to tube bundle 226c) can also be provided.

[0059] In section 220, two U-shaped tube bundles 225, 226 are arranged, which fluidically connect the sub-chambers 211a and 211b of the head chamber 205. The tube bundles 225, 226 each have vertical tube bundle sections 225a, 225b; 226a, 226b, which are fluidically connected at their lower ends by a tube sheet 225c and a curved tube bundle section 226c, respectively. The tube bundles 225, 226 extend to different depths into the condenser housing 202; while tube bundle 225 does not extend deeper than a height above the overflow 215, tube bundle 226, with its tube sheet section 226c, is immersed in the liquid condensate bath 219.

[0060] Furthermore, in both section 220 and section 221, a plurality of flow guide plates 227 are provided, which in sections 220 and 221 each force a gas flowing from the carrier gas inlet 207 to the carrier gas outlet 208 within the central section 203 into a meandering flow path running downwards in section 220 and upwards in section 221.

[0061] During operation of the device 201, a process gas loaded with a substance to be condensed flows into the condenser housing 202 via the carrier gas inlet 207 and exits it via the carrier gas outlet 208. The gas barrier 216 prevents process gas from flowing out via the overflow 215. In section 220, the process gas is forced into a meandering flow path by the flow guide plates 227, whereby, after each change in direction, the process gas successively comes into contact with the tube bundle sections 226b, 225b, 225a, 226a (in the case of a flow direction from left to right) or 226a, 225a, 225b, 226b (in the case of a flow direction from right to left). Simultaneously, a cold heat transfer medium present in the sub-chamber 211b is fed into the tube bundle sections 225a, 226a. The heat transfer medium flows parallel through the tube bundles 225, 226 to the sub-space 211a and is discharged via the outlet 214.Upon thermal contact with the tube bundle sections 226a, 225a, 225b, the process gas is cooled to a temperature below the dew point temperature of the substance to be condensed. This results in the formation of a liquid condensate on the surface of the tube bundle sections 226a, 225a, 225b, which flows to the sump 206 and forms the condensate bath 219 there.

[0062] Since the curved tube bundle section 226c of the tube bundle 226 runs through the condensate bath 219, the heat transfer medium flowing through the tube bundle 226 comes into thermal contact with the liquid condensate and is thereby heated; simultaneously, the condensate is cooled in the sump 206. The heat transfer medium flowing through tube bundle section 226b is therefore at a higher temperature than that flowing through tube bundle sections 225a, 225b, and 226a. As a result, after each change in direction of the process gas in the region of tube bundle section 226b, the process gas, which was previously cooled in the tube sections 225a, 225b, and 226a, is heated, and any aerosols of the substance to be condensed that have previously formed evaporate again. The heat transfer medium carried through the pipe sections 225b, 226b is then discharged via the sub-chamber 211a and the outlet 214.

[0063] The process gas then flows into section 221 and is cooled there due to thermal contact with the heat transfer medium supplied via line 213, fed into tube bundle section 222a via sub-chamber 212, and guided through tube bundle 222. The heat transfer medium is, for example, a cryogenically liquefied gas that evaporates upon thermal contact with the process gas at tube bundle 222. Tube bundle 222 thus acts as a cryogenic heat exchanger, where the process gas is further cooled to remove any remaining residue of the substance to be condensed as much as possible through condensation.Depending on the dew point and melting point of the substance(s) to be condensed, freezing of the substance(s) on the tubes of tube bundle sections 222a and 222b may occur in this area; in this case, the device 201 must be defrosted from time to time to maintain its full performance. Since there are virtually no aerosols left in the process gas in section 221, an evaporation zone is unnecessary there.

[0064] The heat transfer medium, which heats up and may evaporate upon contact with the process gas at the tubes of the tube bundle 222, flows into the sub-chamber 211b. There, it then serves as a heat transfer medium for cooling the process gas in section 220 by being passed through the tube bundle heat exchangers 225 and 226, as described above. Overall, the operating temperature is therefore higher in section 220 than in section 221.

[0065] Furthermore, it is conceivable (not shown here) that the condenser housing 202 is divided not only into two sections 220, 221, but into three or more sections, each containing tube bundles that are successively traversed by the heat exchanger medium in the manner described, thereby bringing about thermal contact between the heat exchanger medium and the process gas. Such sections can also be arranged one above the other within the condenser housing.

[0066] Due to the strong cooling of the process gas in section 221, the residual cold of the treated process gas can be used to cool the untreated process gas in section 220. For this purpose, in the exemplary embodiment according to Fig. 3. A partial flow of the process gas exiting the carrier gas outlet 208 is fed via a conduit 228 (indicated here only by a dashed line) to a tube bundle arranged in section 220, which functions as a recuperator 230 by bringing the comparatively cold, treated process gas into indirect thermal contact with the comparatively warm, untreated process gas. Furthermore, such a recuperator can also be arranged elsewhere, for example upstream of the carrier gas inlet 207.

[0067] The in Fig. The device 301 shown in Figure 4 is characterized by a concentric arrangement of the tube bundles used as heat exchanger surfaces. Similar to the previously shown embodiments, the device 301 comprises a vertically arranged, thermally well-insulated condenser housing 302, which has a cylindrical central section 303, a head section 305 separated from it by a tube sheet 304, and a sump 306. A carrier gas inlet 307 opens laterally into the central section 303. A process outlet 308 passes through the head section 305 and the tube sheet 304, opening into the central section 303 approximately in the middle of the tube sheet 304.

[0068] The head chamber 305 is divided by cylindrical and coaxially arranged partitions 309a, 309b into fluidically separated, concentrically arranged sub-chambers 310, 311, 312, namely an inner sub-chamber 310, a middle sub-chamber 311 and an outer sub-chamber 312. A supply line 313 for a heat transfer medium, in the embodiment shown here liquid nitrogen (LIN), opens into the inner sub-chamber 310, and an outlet line 314 for the heat transfer medium, which is heated and possibly evaporated during operation of the device 301, opens into the outer sub-chamber 312. In the embodiment shown here gaseous nitrogen (GAN), this heat transfer medium opens into the outer sub-chamber 312. The central compartment 311 has no connection to the outside of the condenser housing 302. The sump 306 is, as in the previously shown embodiments, equipped with an overflow 315 and a gas barrier 316.

[0069] Concentric to a longitudinal axis 317 of the central section 303, a separating tube 318 is arranged, extending within the central section 303 from the tube sheet 304 down to a height just above the overflow 315 and thus above a condensate bath 319 located in the sump 306 during operation of the device 301. The separating tube 318 divides the central section 303 into two functional sections, an inner section 320 and an outer section 321, of which—similar to devices 101, 201—one section (here section 320) serves to remove the aerosols from the process gas, while in a second section (here section 321) any remaining residual charge in the process gas is reduced.

[0070] In the inner section 320, a tube bundle 322 is arranged, which fluidically connects the inner sub-chamber 310 with the central sub-chamber 311 of the head chamber 305. The tube bundle 322 has vertical tube bundle sections 322a, 322b, which are fluidically connected at their lower end by a tube sheet 323 or via curved tube bundle sections (not shown here). The tube bundle 322 extends only so far within the central section 303 that it is not wetted by the condensate bath 319 during operation of the device 301; the tube sheet 323 is therefore arranged vertically above the overflow 315.

[0071] In the outer section 321, two tube bundles 325, 326 are arranged, through which the middle sub-chamber 311 and the outer sub-chamber 312 of the head chamber 305 are flow-connected. The tube bundles 325, 326 each have vertical tube bundle sections 325a, 325b; 326a, 326b, which are flow-connected at their lower end via a tube sheet 325c or via U-shaped curved tube bundle sections 326c. The tube bundles 325, 326 extend to different depths into the condenser housing 302; while tube bundle 325 does not extend deeper than a height just above the sump 306, the outer tube bundle 326 with its tube sheet section 326c extends deep into the sump 306 below the level of the overflow 315. Furthermore, in Fig.4 the tube bundles 322, 325, 324, each consisting of a plurality of parallel tubes, are only indicated by individual tubes; in particular, the tube bundles 322, 325, 326 extend with a plurality of tubes over the entire direction of rotation of the central section 303.

[0072] Furthermore, a plurality of crescent-shaped or annular flow guide plates 327 are arranged in both the inner section 320 and the outer section 321 of the central section 303. The flow guide plates 327 force a process gas guided through the respective section 320, 321 into a meandering flow path, whereby the process gas is guided downwards in the outer section 321 and upwards in the inner section 320.

[0073] During operation of the device 301, a process gas loaded with a substance to be condensed flows into the condenser housing 302 via the carrier gas inlet 307 and exits it at the carrier gas outlet 308. The gas barrier 316 prevents process gas from flowing out via the overflow 315.

[0074] In the outer section 321, the process gas is forced into a meandering flow path radially by the flow guide plates 327. At each flow reversal, it successively comes into contact with the tube bundle sections 326a, 325a, 325b, 326b (in the case of radial outward flow) or the tube bundle sections 326b, 325b, 325a, 326a (in the case of radial inward flow). Upon thermal contact with the tube bundle sections 326a, 325a, 325b, the process gas is cooled to below the condensation temperature of the loaded substance. As a result, condensate forms on the tube bundle sections 326a, 325a, 325b, which subsequently flows into the condensate bath 319 in the sump 306. At the same time, undesirable aerosols containing the substance to be condensed are formed in the vicinity of the tube bundle sections 326a, 325a, 325b.

[0075] The heat transfer medium flows parallel through the tube bundles 325 and 326 to the sub-chamber 312 and is discharged via the outlet 314. Since the curved tube bundle section 326c of the tube bundle 326 runs through the condensate bath 319, the heat transfer medium flowing through the tube bundle 326 comes into thermal contact with the liquid condensate and is thus heated; simultaneously, the condensate is cooled in the sump 306. The heat transfer medium flowing through tube bundle section 326b is therefore at a higher temperature than the heat transfer medium flowing through tube bundle sections 325a, 325b, and 326a. As a result, after each reversal of direction of the process gas in the area of ​​the tube bundle section 326b, the process gas, which was previously cooled at the pipe sections 325a, 325b and 326a, is heated, and aerosols that have previously formed evaporate and are again subjected to condensation.

[0076] After passing through the outer section 321, the process gas flows into the inner section 320, where it is cooled to a very low temperature by the tube bundle 322, which functions as a cryogenic heat exchanger. During this process, it is again forced into a meandering path by flow guides 327, coming into contact with the tube bundle sections 322a and 322b after each change in direction. Simultaneously, a cryogenic, preferably liquefied heat transfer medium, for example liquid nitrogen, is fed into the tube bundle section 322a via the inner subchamber 310 of the headspace 305, passes through the tube bundle section 322b and thus enters the middle subchamber 311 of the headspace 305. The process gas is thereby cooled at the tube bundle 322 to a temperature lower than the temperature of the process gas at the heat exchanger surfaces 325a, 325b and 326a in the outer section 321.Simultaneously, the heat transfer medium in the tube bundle 322 evaporates through thermal contact with the process gas. Since there are virtually no aerosols left in the process gas in the inner section 320, an evaporation zone is unnecessary there.

[0077] The treated process gas finally flows out via the process gas outlet 308. Because it is still at a low temperature, it is also optionally possible to connect a recuperator (not shown here) upstream of the device 301 or to integrate a recuperator into the apparatus, in which the treated process gas is brought into thermal contact with the untreated process gas.

[0078] The device 301 enables particularly efficient operation because the tube bundle 322, which operates at the lowest temperature, is arranged radially on the inside, and the tube bundle section 326b, which operates at the highest temperature, is arranged radially on the outside. This reduces cooling losses due to the unavoidable heat input through the wall of the condenser housing 302. In certain applications, thermal insulation of the condenser housing 302 can even be omitted. The radially symmetrical arrangement of the tube bundles 322, 325, 326 also simplifies the flow path of the process gas and allows for a closer approximation of an equilibrium loading, thereby increasing the separation efficiency.

[0079] Furthermore, the vertical arrangement shown in the exemplary embodiments presented here is by no means mandatory within the scope of the invention; other arrangements are also conceivable, for example, condensers with a horizontal housing. Moreover, the devices 1, 101, 201, and 301 can each be equipped with a process control device (not shown here) by means of which the supplied flow rates of process gas and heat transfer medium can be regulated according to the respective task. Reference symbol list 1 Device 2 capacitor housings 3 Central section 4 Tube sheet 5 headroom 6 Swamp 7 Carrier gas inlet 8 Carrier gas outlet 9 Partition wall 10 - 11 sub-areas 12 sub-rooms 13 Supply line 14. Expulsion 15 Overflow 16 Gas lock 17 tube bundles 17a, 17b, 17c Tube bundle sections 18 tube bundles 18a, 18b, 18c Tube bundle sections 19 Flow guides 20 Flow path 21 levels 22 Condensate bath 23 Evaporation area 24 Heating system 101 Device 102 capacitor housings 103 Central Section 104 Tube sheet 105 headroom 106 Swamp 107 Carrier gas inlet 108 Carrier gas outlet 109 Partition wall 110 - 111 sub-area 112 sub-area 113 Supply line 114 Detoxification 115 Overflow 116 Gas lock 117 tube bundles 117a, 117b, 117c tube bundle sections 118 tube bundles 118a, 118b, 118c Tube bundle sections 119 Partition wall Section 120 Section 121 122 Flow guide plate 123 Condensate bath 124 Evaporation area 201 Device 202 Capacitor housings 203 Central Section 204 Tube sheet 205 headroom 206 Swamp 207 Carrier gas inlet 208 Carrier gas outlet 209 Partition wall 210 partition wall 211a, 211b Sub-area 212 sub-area 213 Supply line 214 Detoxification 215 Overflow 216 Gas lock 217 - 218 Partition wall 219 Condensate bath Section 220 Section 221 222 tube bundles 222a, 222b Tube bundle section 223 Tube sheet 224 - 225 tube bundles 225a, 225b, 225c tube bundle section 226 tube bundles 226a, 226b, 226c Tube bundle section 227 Flow guide plate 228 Line 229 - 230 recuperator 301 Device 302 Capacitor housing 303 Central Section 304 Tube sheet 305 headroom 306 Swamp 307 Carrier gas inlet 308 Carrier gas outlet 309a, 309b Partition wall 310 Inner sub-space 311 Middle sub-area 312 Outer sub-area 313 Supply line 314 Detoxification 315 Overflow 316 Gas lock 317 Longitudinal axis 318 Separating pipe 319 Condensate bath 320 Inner Section 321 Outer section 322 tube bundles 322a, 322b Tube bundle section 323 Tube sheet 324 - 325 Tube bundles 325a, 325b, 325c tube bundle section 326 tube bundles 326a, 326b, 326c Tube bundle section 327 Flow guide plate

Claims

[1] A method for separating a gaseous or vaporous substance from a carrier gas stream by partial condensation, in which a carrier gas loaded with at least one substance to be condensed is guided through a flow path (20) extending in the housing (2, 102, 202, 302) of a condenser from a carrier gas inlet (7, 107, 207, 307) to a carrier gas outlet (8, 108, 208, 308), within which it is brought into indirect thermal contact with a heat transfer medium at a first heat exchanger surface and is thereby cooled to a temperature below the dew point temperature of the substance to be condensed, wherein the substance at least partially condenses on the heat exchanger surface in the form of liquid condensate, which is subsequently collected in a condensate bath (22) and discharged, wherein The carrier gas, after contact with the first heat exchanger surface, passes through an evaporation zone (23, 124) in the flow path (20) in which a temperature prevails that is higher than the dew point temperature of the substance to be condensed, and the carrier gas is subsequently cooled at a second heat exchanger surface in the flow path (20) in indirect thermal contact with a heat transfer medium to a temperature below the dew point temperature of the substance to be condensed. characterized by , that at least a partial flow of the heat transfer medium used at the first and / or the second heat exchanger surface is brought into thermal contact with the collected condensate in the condensate bath (22) and is subsequently supplied to the evaporation heat exchanger surface (18b, 118b, 226b, 326b) for indirect heat exchange with the carrier gas in the evaporation area (23, 124). [2] Method according to claim 1, characterized by, that the carrier gas, as it passes through the flow path (20), is cooled several times in succession at a first heat exchanger surface or a group of first heat exchanger surfaces, then heated up in an evaporation area (23, 124) and cooled again at a second heat exchanger surface or a group of second heat exchanger surfaces. [3] Method according to claim 1 or 2, characterized by , that the temperature in the evaporation area (23, 124) is maintained by an evaporation heat exchanger surface (18b, 118b, 226b, 326b) arranged in the evaporation area (23, 124), on which the carrier gas is brought into indirect thermal contact with a heat transfer medium whose temperature is above the dew point temperature of the substance to be condensed in the carrier gas. [4] Method according to any one of the preceding claims, characterized by, that the condensate and / or the heat transfer medium supplied to the evaporative heat exchanger surface (18b, 118b, 226b, 326b) is heated. [5] Method according to any one of the preceding claims, characterized by that the cooling medium used at the first heat exchanger surface and the cooling medium used at the second heat exchanger surface are taken from a common source. [6] Method according to any one of the preceding claims, characterized by , that a liquefied gas, such as liquid nitrogen, is used as the heat transfer medium on at least one of the heat exchanger surfaces, which at least partially evaporates through indirect thermal contact with the carrier gas. [7] Method according to any one of the preceding claims, characterized by , that at least a partial stream of the treated carrier gas is brought into thermal contact with the untreated carrier gas at a recuperator (230). [8] Device for separating a gaseous or vaporous substance from a carrier gas stream by partial condensation, comprising a condenser having a housing (2, 102, 202, 302) through which a flow path (20) for a carrier gas loaded with at least one substance to be condensed extends between a carrier gas inlet (7, 107, 207, 307) and a carrier gas outlet (8, 108, 208, 308), in which flow path (20) a plurality of heat exchangers are arranged, each equipped with an inlet and an outlet for a heat transfer medium and with a heat exchanger surface for indirect thermal contact of the carrier gas with a heat transfer medium, and with a device for collecting and discharging the condensate from the condensed substance produced during indirect heat exchange, wherein in the flow path of the carrier gas - viewed in the direction of flow - a first heat exchanger with a first heat exchanger surface and a second heat exchanger with a second heat exchanger surface are arranged spaced apart one behind the other, and means for heating the carrier gas are provided in an evaporation area (23, 124) arranged between the first heat exchanger surface and the second heat exchanger surface, characterized by , that the means for heating the carrier gas in the evaporation area (23, 124) comprise an evaporation heat exchanger equipped with an inlet and outlet for a heat transfer medium and an evaporation heat exchanger surface (18b, 118b, 226b, 326b) and The supply line for the heat transfer medium of the evaporative heat exchanger is connected to the outlet for the heat transfer medium of the first and / or the second heat exchanger, with means for heating the heat transfer medium being provided downstream to the heat exchanger surface of the respective heat exchanger, but upstream to the evaporative heat exchanger surface (18b, 118b, 226b, 326b). The means for heating the heat transfer medium comprise a condensate bath (22, 123, 219, 319) in which a heat exchanger surface (18c, 118c, 226c, 326c) is arranged for heating the heat transfer medium. [9] Device according to claim 8, characterized by , that in the flow path (20) of the carrier gas more than two heat exchanger surfaces are arranged one after the other, which are successively supplied by the carrier gas, wherein at least between some of the heat exchanger surfaces evaporation areas (23, 124) are arranged in which means for heating the carrier gas are arranged. [10] Device according to claim 8 or 9, characterized by , that the first heat exchanger and / or the second heat exchanger is / are designed as a tube bundle (17, 18; 117, 118; 225, 226; 325, 326) through which a heat transfer medium flows. [11] Device according to claim 10, characterized by , that the flow path (20) of the carrier gas is meandering around tube bundles (17, 18; 117, 118; 225, 226; 325, 326) of the first and second heat exchangers arranged parallel to each other. [12] Device according to any one of claims 8 to 11, characterized by , that means for tempering the condensate are provided in the condensate bath (22, 123, 219, 319). [13] Device according to any one of claims 8 to 12, characterized by , that in the flow path (20) of the carrier gas, downstream to the second heat exchanger, a deep-freeze heat exchanger is arranged. [14] Device according to any one of claims 8 to 13, characterized by, that the heat exchanger surfaces (325a, 325b, 326a) of the first heat exchanger and / or the second heat exchanger and the evaporative heat exchanger are designed as tube bundles (325a, 325b, 326a, 326b) which run concentrically to each other at least in a section of the condenser housing (302), wherein the tube bundles (325a, 325b, 326a) of the first heat exchanger and / or the second heat exchanger are arranged radially within the tube bundle (326b) of the evaporative heat exchanger.

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