Discontinuously operated desublimer having at least one perforated plate

Abstract

The invention relates to a discontinuously operated desublimer (1) for removal of at least one gas component to be desublimed from a gas mixture flow, comprising a housing wall (7), an inlet (2) on the housing wall (7) to supply the gas mixture flow to the desublimer (1), an outlet (6) on the housing wall (7) for removing the treated gas mixture flow from the desublimer (1), a desublimation zone (4) having temperature-controllable flow channel walls, wherein the temperature of the flow channel walls is adjustable such that, during a loading process, the at least one gas component to be desublimed is desublimed on the flow channel walls, and such that, during a subsequent melting process, the at least one gas component desublimed in the loading process melts on the flow channel walls, a gas inlet distributor space (3) between the inlet (2) and the desublimation zone (4), and a gas outlet space (5) between the outlet (6) and the desublimation zone (4). According to the invention, at least one first perforated plate (8) disposed in the gas inlet distributor space (3) for uniform distribution of the gas mixture flow through the flow channels that arise from the flow channel walls of the desublimation zone (4) has a geometric centroid having a distance (AT) from the desublimation zone (4) in the range from 0 to Amax, preferably in the range from 0 to 0.5 * Amax and more preferably in the range from 0.03 to 0.3 * Amax, where Amax corresponds to the distance between the inlet area (9) of the inlet (2) and the desublimation zone (4), and where the at least one first perforated plate has a porosity in the range from 5% to 50%, preferably 10% to 30%, more preferably 10% to 20%. The invention further provides a method of operating a desublimer (1) of the invention.

Description

[0001] Discontinuously operated desublimator with at least one perforated plate

[0002] Description

[0003] The invention relates to a discontinuously operated desublimator for removing at least one gas component to be desublimated from a gas mixture flow, which comprises a housing wall, an inlet on the housing wall for supplying the gas mixture flow, an outlet on the housing wall for discharging the treated gas mixture flow and a desublimation zone with temperature-controlled flow channel walls, wherein the flow channel walls are temperature-controlled such that during a loading process the at least one gas component to be desublimated desublimates on the flow channel walls, and that during a subsequent melting process the at least one gas component desublimated in the loading process melts on the flow channel walls.

[0004] In addition, the desublimator comprises a gas inlet distribution chamber located between the inlet and the desublimation zone and a gas outlet chamber located between the outlet and the desublimation zone.

[0005] Known discontinuously operated desublimators have flow channel walls inside them, which can be in the form of bundles of finned tubes. Finned tubes are characterized by the fact that their tubes are surrounded by fins, whereby the fins can be heated or cooled by a fluid flowing through the tubes. During the loading process, a gas component to be desublimated contained in a gas or gas-vapor mixture is recovered by desublimating the gas component to be desublimated on the cooled fins. In a subsequent melting process, the gas component desublimated on the now heated walls of the finned tubes is melted and discharged from the desublimator. Instead of finned tubes, other designs of flow channel walls, such as fins or honeycombs, can also be arranged in the desublimator.When using fins, the cooling or heating medium is usually guided through fluid lines that are usually arranged on the outside of the housing walls, so that the heat transfer takes place essentially between the externally arranged fluid lines and the housing wall and between the housing wall and the fins.

[0006] In the desublimators described above, the gas mixture flow during the loading process exhibits poor uniformity with respect to the flow through the flow channels, causing the gas component to be desublimated to desublimate unevenly on the flow channel walls. As a result, the pressure loss between the inlet and outlet of the desublimator increases more rapidly during the loading process, and the desublimator must therefore be regenerated at shorter intervals, even though its maximum loading capacity has not yet been reached. The desublimator is typically regenerated through the melting process and an optional, subsequent recooling process.

[0007] DE3407104 A1 discloses discontinuously operated desublimators for separating products from gas mixtures. These desublimators have fins as flow channel walls inside them, which are attached to the housing side walls. A cooling or heating medium is guided through fluid lines arranged only on the outer housing side walls. Heat transfer occurs during heating of the fins from the fluid lines to the housing side walls and from the housing side walls to the fins, whereas heat transfer during cooling of the fins occurs from the fins to the housing side walls and from the housing side walls to the fluid lines. These desublimators are used, for example, in the production of phthalic anhydride (PSA).

[0008] However, this results in larger parasitic heat losses to the environment, since the desublimator is only heated or cooled from the outside. For larger desublimators with an internal volume of, for example, more than 1 m 3 However, during desublimator operation, the heat transfer between the housing side walls and the fins further away from the housing side walls is generally too low, resulting in a temperature gradient within the fins during the loading process, which leads to different desublimation rates. As a result, the pressure loss increases more rapidly during the loading process, and the desublimator must be regenerated at shorter intervals, even though its maximum loading capacity has not yet been reached.

[0009] DE102015101398 A1 discloses a discontinuously operated desublimator in a cylindrical design for removing a gas component to be desublimated from a gas flow. The desublimator comprises a housing containing an inner fluid line and fins as flow channel walls, which are arranged on an inner side of the housing wall and are directed inward. The fins can also be cooled by a coolant flowing through the inner fluid line or heated by a heating medium flowing through the inner fluid line. However, if such desublimators have an internal volume of, for example, more than 1 m 3, then the heat transfer from the inner fluid line to the locations on the fins further away from the fluid line is generally too low, resulting in a temperature gradient within the fins, which leads to different desublimation rates during the loading process. The longer design of such desublimators has the disadvantage that desublimation occurs particularly at those locations on the fins that are close to the inlet of the gas mixture flow. This can cause the fins in the inlet area to become clogged quickly, even if desublimation has not yet taken place on all wall surfaces of the fins. Due to the disadvantages described above, the pressure loss increases more quickly during the loading process and the desublimator must therefore be regenerated at shorter intervals, even though its maximum loading capacity has not yet been reached.

[0010] The task was therefore to provide a desublimator that achieves the most evenly distributed gas mixture flow through the flow channels of the desublimation zone during its loading process. A further objective was to ensure that the pressure loss between the desublimator inlet and outlet increases as slowly as possible during the desublimator loading process, thus allowing the desublimator to be regenerated at longer intervals. Furthermore, the task was to provide a desublimator with a larger loading capacity for desublimating gas components at a given maximum pressure loss between the desublimator inlet and outlet or at a given maximum loading time for the loading process.

[0011] These objects are achieved according to the present invention by a discontinuously operated desublimator according to claim 1 and by a method for operating the desublimator according to claim 13. Advantageous embodiments of the desublimator are given in claims 2 to 12, whereas advantageous embodiments of the method for operating the desublimator are given in claims 14 and 15.

[0012] The discontinuously operated desublimator according to the invention for removing at least one gas component to be desublimated from a gas mixture flow comprises a housing wall, an inlet on the housing wall for feeding the gas mixture flow into the desublimator, an outlet on the housing wall for discharging the treated gas mixture flow from the desublimator, a desublimation zone with temperature-controlled flow channel walls, wherein the flow channel walls are temperature-controlled such that during a loading process the at least one gas component to be desublimated desublimates on the flow channel walls, and that during a subsequent melting process the at least one gas component desublimated in the loading process melts on the flow channel walls, a gas inlet distribution space located between the inlet and the desublimation zone, and a gas outlet space located between the outlet and the desublimation zone.

[0013] According to the invention, at least one first perforated plate is arranged in the gas inlet distribution chamber for the uniform distribution of the gas mixture flow through the flow channels resulting from the flow channel walls of the desublimation zone, the geometric center of gravity of which has a distance A T to the desublimation zone in the range from 0 to A ma x, preferably in the range of 0 to 0.5 * Amax and particularly preferably in the range of 0.03 to 0.3 * A ma x, wherein Amax corresponds to the distance between the inlet surface of the inlet and the desublimation zone, and wherein the at least first perforated plate has a porosity in the range of 5 to 50%, preferably in the range of 10 to 30% and particularly preferably in the range of 10 to 20%.

[0014] The first or subsequent perforated plates in the gas inlet distribution chamber distribute the incoming gas mixture flow more evenly through the individual flow channels of the desublimation zone during the loading process, resulting in more uniform desublimation at the flow channel walls. The more uniform flow through the flow channels and the more uniform desublimation at the flow channel walls prevent excessive gas mixture flow velocities, which can sometimes be far more than twice the average gas mixture flow velocity through the desublimation zone. Furthermore, the interaction between the flow channel walls and the gas mixture flow is enhanced.

[0015] Due to the desublimation of at least one gas component to be desublimated, the surfaces of the flow channel walls are coated, causing the pressure loss across the individual flow channels to increase accordingly during the loading process. Due to the more uniform flow through the flow channels and the more uniform desublimation at the flow channel walls, the pressure loss across the individual flow channels increases less. Thus, the pressure loss between the inlet and outlet of the desublimator according to the invention also increases less during the loading process, and the desublimator can therefore be regenerated at longer intervals.In addition, the desublimator according to the invention can desublimate more of the at least one gas component to be desublimated at its flow channel walls compared to a desublimator without a perforated plate at the same pressure loss between the inlet and the outlet of the desublimator, whereby the desublimator according to the invention with at least one first perforated plate achieves a larger loading capacity at the same pressure loss.

[0016] In this document, the term "gas mixture flow" generally refers to a flowing gas mixture. The gas mixture can also be a gas-vapor mixture. In principle, the gas mixture can contain liquid droplets or solid particles, provided that they do not damage or clog the desublimator.

[0017] In this document, the term "a gas component to be desublimated" generally refers to a gas component that desublimates predominantly at flow channel walls within a desublimation zone, where the flow channel walls have a lower temperature than the desublimation temperature during a loading process. In thermodynamics, desublimation is the process of the immediate transition of a substance from the gaseous to the solid state. The desublimation temperature indicates the maximum temperature at a given pressure below which a gas component changes to the solid state.

[0018] In this document, the term "fluid line" refers to a line through which a cooling or heating medium can flow. The fluid line can be arranged on the outside of the housing wall and / or inside the desublimator. If one or more fluid lines are arranged on the outside, heat transfer takes place between the fluid line(s) and the housing wall, whereby the gas mixture flow in contact with the inside of the housing wall can be temperature controlled. In addition, the flow channel walls can also be temperature controlled if the flow channel walls are thermally coupled to the inside of the housing wall. If one or more fluid lines are arranged inside the desublimator, heat transfer generally takes place predominantly between the fluid line(s) and the flow channel walls, whereby the flow channel walls can be temperature controlled.

[0019] In this document, the term "housing wall" generally refers to the outer boundary of the desublimator. Typically, the housing wall is also referred to as a shell in the literature. The walls of the housing wall have sufficient technical tightness. Typically, the outer side of the housing wall is at least partially heated by an external heating element. As a rule, the external heating element is provided by one or more fluid lines, which are typically mounted directly on the outer side of the housing wall. During operation of the desublimator, a cooling or heating medium is usually conveyed through the fluid line(s) in order to be able to control the temperature of the gas mixture flow and / or the flow channel walls accordingly. One or more inlet and outlet surfaces are provided by a respective recess in the housing wall.

[0020] In this document, the term "desublimation zone with temperature-controlled flow channel walls" generally refers to an area in which, during a loading process, at least one gas component to be desublimated is desublimated at the flow channel walls, and the remaining gas mixture flow, also referred to as the treated gas mixture flow, flows out of the desublimation zone and thus reaches the gas outlet space. In a melting process following the loading process, the flow channel walls of the desublimation zone are heated to melt the gas component(s) desublimated at the flow channel walls and to remove them from the desublimator. The temperature-controlled flow channel walls of the desublimation zone can be provided, for example, by the outer walls of finned tubes, finned tube bundles, tube bundles, finned bodies, honeycomb bodies, tube rods, tube rod bundles, or plate bodies.Lamellar, plate, or honeycomb bodies are components that contain lamellae, plates, or honeycombs, respectively. In the case of a lamellar body, the cavities between the individual lamellae form the flow channels. Accordingly, the flow channel walls are provided by the lamellar surfaces. In the case of finned tubes, the adjacent fins form a cavity that serves as a flow channel through which a fluid, such as a gas mixture, can flow. As a rule, bundles of finned tubes are arranged in the desublimation zone, whereby, for example, adjacent finned tubes can form further flow channels, or individual finned tubes in combination with adjacent finned tubes can form continuous flow channels.

[0021] The flow channels can all have the same channel diameter by equidistantly spacing the fins of the finned tube(s). However, the flow channels preferably have different channel diameters by spaced apart the fins of the finned tube(s). When flowing through the flow channels, it can be advantageous for more uniform flow through the flow channels if the channel diameter is larger at the inlet of the respective flow channel than at the outlet of the respective flow channel. In addition, the at least one gas component to be desublimated desublimates more evenly at the flow channel walls over the length of the respective flow channel. The tube shape of the finned tube(s) can be circular, oval, or square.

[0022] Furthermore, the inlet area of ​​the desublimation zone is defined by the fictitious separation area between the gas inlet distribution space and the desublimation zone, whereby the surfaces of the respective flow channel walls located in the separation area are also assigned to the inlet area of ​​the desublimation zone for simplification.

[0023] The outlet area of ​​the desublimation zone is defined by the fictitious separation area between the gas outlet distribution chamber and the desublimation zone, whereby the surfaces of the respective flow channel walls located in the separation area are also assigned to the outlet area of ​​the desublimation zone for simplification.

[0024] The ratio between the inlet area of ​​the desublimation zone and the distance between the inlet and outlet areas of the desublimation zone should preferably be greater than 5 [m 2 / m], where the inlet area in square meters [m 2] and the distance between the inlet and outlet surfaces of the desublimation zone is to be measured in meters [m]. By adhering to the preferred range for the ratio, significantly excessive desublimation at flow channel walls in the region of the inlet surface of the desublimation zone is avoided. This is because increased desublimation at a flow channel wall significantly reduces the minimum free gas passage area of ​​the flow channel in question within a very short loading time, which would rapidly increase the pressure loss across the flow channel in question at the beginning of the loading process and ultimately block the flow channel in question after a very short loading time, even if desublimation at the flow channel wall in question essentially only takes place in the region of the inlet surface of the desublimation zone.

[0025] The more inlet area is available, the less likely increased desublimation at the flow channel walls in the area of ​​the inlet area of ​​the desublimation zone can lead to a significantly greater pressure loss or even to blockage.

[0026] In order to design a desublimator in a cost-effective and space-saving manner, the ratio between the inlet area of ​​the desublimation zone and the distance between the inlet and outlet areas of the desublimation zone should preferably be less than 100 [m 2 / m], where the inlet area in square meters [m 2 ] and the distance between the inlet and outlet surfaces of the desublimation zone is to be measured in metres [m].

[0027] To control the temperature of the flow channel walls of the desublimation zone, one or more flowable fluid lines can be arranged within the desublimation zone, for example, through which a heating or cooling medium can flow, thus controlling the temperature of the walls of the fluid line(s). The flow channel walls are accordingly temperature-controlled through the heat transfer between the flow channel walls and the flowable fluid line(s). Additionally or alternatively, temperature control can be achieved by an external, flowable fluid line or by several external, flowable fluid lines arranged on the outside of the housing wall.In this case, the flow channel walls of the desublimation zone are tempered accordingly by the heat transfer between the flow channel walls of the desublimation zone and the outer, flowable fluid line(s), whereby the heat transfer naturally also takes place through the housing wall in between.

[0028] If a coolant flows through the inner or outer fluid line(s) during the loading process, the walls of the flow channels are cooled due to heat conduction between the flow channel walls and the fluid line(s), so that the at least one gas component to be desublimated can desublimate on the walls of the flow channels. If a heating medium flows through the inner or outer fluid line(s) during the melting process, the walls of the flow channels are heated due to heat conduction between the flow channel walls and the fluid line(s), so that the gas component(s) desublimated on the walls of the flow channels can melt. For example, a different or the same heat transfer oil, such as Diphyl DT, can be used as the heating or coolant.

[0029] In this document, the term "desublimated at the flow channel walls" generally refers to a deposition process in which at least one gas component to be desublimated contained in a gas mixture flow is cooled to such an extent that it desublimates and deposits on the flow channel walls. The desublimated gas component(s) adhere(s) accordingly to the flow channel walls in the solid state.

[0030] Depending on the prevailing thermodynamic conditions, the term "desublimated" can also be understood in this document to mean that in the desublimation zone, a phase change initially occurs in at least a portion of the gas mixture flow from a gaseous to a liquid state, and only then does a phase change from the liquid to the solid state occur. The flow channel walls of the desublimation zone are accordingly at least partially wetted with the liquid created by the phase change. Due to the cooled flow channel walls, the phase change from the liquid to the solid state takes place at the flow channel walls within a very short time. In summary, in this case too, the gas component to be desublimated on the flow channel walls of the desublimation zone and accordingly adheres to the flow channel walls in the solid state.

[0031] In this document, the term "gas inlet distribution chamber" generally refers to a chamber within the desublimator defined by the housing wall of the desublimator, the inlet surface of the desublimator, and the desublimation zone. During a loading process, a gas mixture flows through the gas inlet distribution chamber, with the gas mixture flowing in through an inlet on the desublimator. Adjacent to the gas inlet distribution chamber is the desublimation zone with temperature-controlled flow channel walls. The gas mixture flow can generally only flow out of the gas inlet distribution chamber through this desublimation zone.

[0032] In this document, the term "gas outlet chamber" generally refers to a chamber into which a gas mixture flow can be fed from its adjacent desublimation zone. This chamber typically also has an outlet through which the treated gas mixture flow can flow out of the desublimator.

[0033] Typically, there is also an additional outlet port with a drain valve, which can be a sealed cap, for example. During a melting process, the drain valve is open, allowing the generated melt to flow out of the desublimator. During a loading process, the drain valve is closed, preventing fluid from flowing out of the outlet port. This additional outlet port is typically located at the lowest point in the gas outlet chamber, allowing the melt to flow to the additional outlet port by gravity.

[0034] In this document, the term "discontinuously operated desublimator" generally refers to a desublimator that is typically operated discontinuously with two or three different process cycles. The first process cycle represents a loading process in which the at least one gas component to be desublimated desublimates on the flow channel walls of the desublimation zone. During the loading process, the flow channel walls are cooled. The second process cycle represents a melting process in which the desublimated gas component(s) melt by heating the flow channel walls of the desublimation zone and are removed from the desublimator.

[0035] The third process cycle represents an optional recooling process, in which the flow channel walls of the desublimation zone are cooled after the desublimated gas component(s) have been removed from the desublimator. Instead of the recooling process, the cooling of the flow channel walls can also take place at the beginning of the loading process.

[0036] In this document, the term "loading process" generally refers to a process cycle during the operation of a desublimator, in which the desublimator is operated until a predetermined loading of one or more desublimated gas components is reached on the flow channel walls of the desublimation zone. The loading is understood to be the deposited mass of one or more desublimated gas components on the flow channel walls.

[0037] In this document, the term "loading capacity" is generally understood to mean the total mass of desublimated gas component or desublimated gas components that desublimate at the flow channel walls during a loading process before the pressure drop between the inlet and outlet of the desublimator exceeds a predetermined value and / or until a predetermined period of time is reached as the loading time.

[0038] In this document, the term "melting process" generally refers to a process cycle during the operation of a desublimator, during which the desublimator has reached its loading capacity and the desublimated gas component(s) subsequently melt by heating the flow channel walls. They can then flow out of the desublimator, for example, through a drain port located at the bottom of the desublimator. Typically, the gas mixture flow into the desublimator is stopped during the melting process. The melting process is also typically referred to as the regeneration process.

[0039] In this document, the term "recooling process" generally refers to an optional process cycle during the operation of a desublimator, in which the flow channel walls of the desublimation zone are cooled after the desublimated gas component(s) have been removed from the desublimator. Typically, the recooling process, in conjunction with the upstream melting process, is also referred to as the regeneration process.

[0040] In this document, the term "perforated plate" generally refers to a component which, during the loading process, ensures that a gas mixture flowing in from the inlet flows as evenly as possible through the flow channels of the desublimation zone. In general, a gas mixture can essentially only flow through the holes in the perforated plate. An example of a possible exception would be a possible gap between the perforated plate and the housing wall of a desublimator, through which a gas mixture could also flow. The perforated plate can also be heated, for example by mounting the perforated plate on the housing side walls of a desublimator in such a way that a sufficient heat flow can flow from the housing side walls to the perforated plate. A heating element for the perforated plate, for example an electric heater in contact with the perforated plate, is also conceivable.

[0041] In this document, the term “hole pitch” defines the distance between two adjacent holes measured from hole center to hole center.

[0042] In this document, the term “hole area” defines the area of ​​a hole in the perforated sheet.

[0043] In this document, the term “total surface of the perforated sheet” refers to the surface of the perforated sheet including its perforated surfaces.

[0044] In this document, the term “free area” defines the total area of ​​all perforated surfaces of the perforated sheet.

[0045] In this document, the term "relative free area of ​​the perforated sheet" defines the ratio between the free area and the total surface of the perforated sheet. For example, a 100 mm x 100 mm perforated sheet has 100 holes, each with a hole area of ​​10 mm. 2 Thus, the total area of ​​all perforated surfaces of the perforated sheet is 1000 mm 2The total surface area of ​​the perforated sheet including the perforated areas is 10000 mm 2 This results in a relative free area of ​​the perforated sheet of 1000 / 10000 = 0.1. In this document, the term "porosity of the perforated sheet" defines the ratio between the free area and the total surface area of ​​the perforated sheet. The "porosity of the perforated sheet" thus corresponds to the "relative free area of ​​the perforated sheet."

[0046] In this document, the term “inflow surface” is generally understood to mean a surface over which a fluid flows and thus a flow pressure acts in the direction of the surface.

[0047] In a preferred embodiment of the desublimator according to the invention, the distance between the geometric center of gravity of the perforated plate and the desublimation zone corresponds to at least twice the distance A min, which results from the arithmetic mean of the distances between the directly adjacent holes of the at least first perforated plate. As a result, in this embodiment, the geometric center of gravity of the at least first perforated plate has a distance from the desublimation zone in the range of 2.0 * A m in to 1.0 * Amax, preferably in the range of 2.0 * A m in up to 0.5 * A ma x , and particularly preferably in the range from 3.0 * Amin to 0.3 * A ma x, where A ma x corresponds to the distance between the inlet surface of the inlet and the desublimation zone.

[0048] In a particularly preferred embodiment of the desublimator according to the invention, the distance between the geometric center of gravity of the perforated plate and the desublimation zone corresponds to at least three times the distance A min, which results from the arithmetic mean of the distances between the directly adjacent holes of the at least first perforated plate. As a result, in this embodiment, the geometric center of gravity of the at least first perforated plate has a distance from the desublimation zone in the range of 3.0 * Amin to 1.0 * Amax, preferably in the range of 3.0 * A m in up to 0.5 * A ma x, where A ma x corresponds to the distance between the inlet surface of the inlet and the desublimation zone.

[0049] In a preferred embodiment of the desublimator according to the invention, the distance between the geometric center of gravity of the perforated plate and the desublimation zone corresponds to at least three times the distance A min, which results from the arithmetic mean of the distances between the directly adjacent holes of the at least first perforated plate. As a result, in this embodiment, the geometric center of gravity of the at least first perforated plate has a distance from the desublimation zone in the range of 3.0 * A m in to 1.0 * Amax, preferably in the range of 3.0 * A m in up to 0.5 * A ma x , and particularly preferably in the range from 5.0 * Amin to 0.3 * A ma x, where A ma x corresponds to the distance between the inlet surface of the inlet and the desublimation zone. In a particularly preferred embodiment of the desublimator according to the invention, the distance between the geometric center of gravity of the perforated plate and the desublimation zone corresponds to at least five times the distance A min, which results from the arithmetic mean of the distances between the directly adjacent holes of the at least first perforated plate. As a result, in this embodiment, the geometric center of gravity of the at least first perforated plate has a distance from the desublimation zone in the range of 5.0 * Amin to 1.0 * Amax, preferably in the range of 5.0 * A m in up to 0.5 * A ma x, where A ma x corresponds to the distance between the inlet surface of the inlet and the desublimation zone.

[0050] In a preferred embodiment of the desublimator according to the invention, the distance between the geometric center of gravity of the perforated plate and the desublimation zone corresponds to at least five times the distance A min, which results from the arithmetic mean of the distances between the directly adjacent holes of the at least first perforated plate. As a result, in this embodiment, the geometric center of gravity of the at least first perforated plate has a distance from the desublimation zone in the range of 5.0 * A m in to 1.0 * Amax, preferably in the range of 5.0 * A m in up to 0.5 * A ma x , and particularly preferably in the range from 10.0 * Amin to 0.3 * A ma x, where A ma x corresponds to the distance between the inlet surface of the inlet and the desublimation zone.

[0051] In a particularly preferred embodiment of the desublimator according to the invention, the distance between the geometric center of gravity of the perforated plate and the desublimation zone corresponds to at least five times the distance A min, which results from the arithmetic mean of the distances between the directly adjacent holes of the at least first perforated plate. As a result, the geometric center of gravity of the at least first perforated plate has a distance from the desublimation zone in the range of 12 * A m in up to 30 * A m in as long as the value 30*A m is smaller than A ma x and particularly preferably the value 30*A m in is less than 0.5 Amax-

[0052] The three last-described preferred embodiments have the advantage that an optimization takes place between the following two factors:

[0053] 1 : The distance between the perforated plate and the desublimation zone:

[0054] The greater the distance, the more homogeneous the flow of the gas mixture to the flow channel walls becomes, since the individual jets from the holes in the perforated plate reduce with increasing distance from the perforated plate.

[0055] 2: The distance between the perforated plate and the inlet surface 9:

[0056] The closer the perforated plate is to the inlet surface, the greater the risk of flow reversal in the perforated plate due to a jet pump effect. This effect can be explained by the high velocities along the perforated plate, which lead to a local pressure drop. If the pressure at the outlet of the flow channel walls is greater than the pressure at the perforated plate, this leads to a flow reversal. In addition, too small a space above the perforated plate can reduce the uniform distribution of the gas mixture flow.

[0057] In a preferred embodiment of the desublimator according to the invention, the at least first perforated plate extends in its width essentially to the two opposite housing side walls of the desublimator. Preferably, the at least first perforated plate has a distance from the walls of the desublimator in the range of 0 to 10 mm, and particularly preferably a distance from the walls of the desublimator in the range of 0 to 1 mm. This offers the advantage that the gas mixture flow is distributed less unevenly across the desublimation zone, thus avoiding the risk of the gas mixture flow flowing predominantly laterally past the perforated plate.

[0058] In a preferred embodiment of the desublimator according to the invention, the at least first perforated plate has a widthwise distance from the housing side walls of the desublimator in the range of 0 to 10 mm, preferably in the range of 0 to 1 mm. This offers the advantage that the gas mixture flow is distributed less unevenly across the desublimation zone and the risk of the gas mixture flowing predominantly laterally past the perforated plate is avoided.

[0059] The width of the perforated plate runs parallel along the transverse axis of the desublimator, with the transverse axis running perpendicular to the main axis of the flow channel walls.

[0060] In a preferred embodiment of the desublimator according to the invention, the at least first perforated plate essentially covers the entire desublimation zone. The at least first perforated plate is spaced from the walls of the desublimator at a distance in the range of 0 to 10 mm, preferably in the range of 0 to 1 mm. This offers the advantage that the gas mixture flow is distributed less unevenly across the desublimation zone, thus avoiding the risk of the gas mixture flow predominantly flowing laterally past the perforated plate.

[0061] In a preferred embodiment of the desublimator according to the invention, in the case of several perforated plates being present, there is a distance between the respective adjacent perforated plates in the range from 0 to 0.50 * Amax, preferably in the range from 0 to 0.25 * Amax, where A max corresponds to the distance between the inlet surface and the desublimation zone. This offers the advantage that the gas mixture flow can initially be more evenly distributed after passing through one perforated plate before flowing through the next perforated plate. This avoids direct flow from one hole to the next hole in the next perforated plate, which ensures a more even distribution of the gas mixture flow at the inlet of the desublimation zone.

[0062] In a preferred embodiment of the desublimator according to the invention, the holes of the at least first perforated plate have different equivalent diameters, wherein the equivalent diameter corresponds to the diameter of a circle of equal area, and wherein the equivalent diameter of the individual holes is preferably in the range from 0.3 to 50.0 mm, particularly preferably in the range from 1.0 to 25.0 mm, and particularly preferably in the range from 5 to 20.0 mm. This offers the advantage that each location at the inlet of the desublimation zone can be locally optimized with regard to uniform distribution by adapting the equivalent diameter of the respective hole of the perforated plate to the gas mixture flow.

[0063] In a particularly preferred embodiment of the desublimator according to the invention, the at least first perforated plate has different equivalent diameters and / or different hole pitches and / or different porosities. This offers the advantage that each location at the inlet of the desublimation zone can be locally optimized with regard to uniform distribution by adapting the equivalent diameter of the respective hole in the perforated plate to the gas mixture flow.

[0064] In a preferred embodiment of the desublimator according to the invention, the holes of the at least first perforated plate, which are located at a distance from the inlet surface in the range from 0.0 mm to L / 2, have a larger equivalent diameter than the more widely spaced holes of the perforated plate, where L corresponds to the length of the longitudinal axis of the gas inlet distribution chamber. Instead of the distance of L / 2, a different distance such as L / 3, L / 4 or L / 5 can also be selected, with the respective dividers 3, 4 or 5 defining the number of regions on the perforated plate, where the holes of the perforated plate can have a different equivalent diameter per region.

[0065] Furthermore, instead of the distance of L / 2, another distance can be selected, such as a distance in the range of 0.1 to 0.9 * L.

[0066] This offers the advantage that the gas mixture flow through the desublimation zone can be optimized independently of each other in a front and a rear area in the main flow direction of the gas inlet distribution chamber.

[0067] In a further preferred embodiment of the desublimator according to the invention, the holes of the at least first perforated plate each have an equivalent diameter that is dimensioned as a function of the distance between the inlet surface (9) and the respective hole. Preferably, the dependence of the respective equivalent diameter on the distance represents a continuous gradient. This offers the advantage that the gas mixture flow through the desublimation zone can be optimized independently of one another in a front and a rear region in the main flow direction of the gas inlet distribution chamber.

[0068] In a preferred embodiment of the desublimator according to the invention, the at least first perforated plate (8) has circular, elongated, elliptical, oval, rectangular, or polygonal holes. This offers the advantage that the holes can be efficiently produced in the perforated plate and that, in the event of desublimation at a hole edge, the gas mixture flow does not immediately become impervious to the hole in the perforated plate.

[0069] In a preferred embodiment of the desublimator according to the invention, the number of holes of the at least first perforated plate is in the range of 100 to 15000 per m 2 -Perforated sheet area, preferably in the range of 1000 to 4000 per m 2 -perforated sheet surface, and the holes preferably correspond to the pattern of an equilateral triangle.

[0070] This offers the advantage that with comparable uniform distribution the pressure loss across the perforated sheet is lower.

[0071] In principle, patterns other than an equilateral triangle are also conceivable, such as a general triangle, a quadrilateral or a polygon.

[0072] In a preferred embodiment of the desublimator according to the invention, the holes of the at least first perforated plate have a pitch in the range of 5 to 50 mm, preferably in the range of 20 to 40 mm. This offers the advantage that in the event of desublimation at a hole edge, the hole in the perforated plate does not immediately become impervious to flow, and the hole size can be adapted to the distance between the flow channel walls.

[0073] In a preferred embodiment of the desublimator according to the invention, several holes, preferably most of the holes, particularly preferably all of the holes, of the at least first perforated plate are arranged in such a way that the flow channel walls projected perpendicularly onto the plane of the at least first perforated plate form a pattern with the geometric centers of gravity of the holes, wherein in the pattern one of the projected flow channel walls overlaps with the nearest geometric center of gravity of the corresponding hole or has a maximum distance of up to 0.50 * D Mit or with the nearest geometric center of gravity of the corresponding hole at a distance of 0.50 * DMÜ, where Dia corresponds to the equivalent diameter geometrically averaged over all flow channels, and where each individual equivalent diameter corresponds to a circle with the same area as the respective flow channel and each individual equivalent diameter is measured at the inlet of the desublimation zone.

[0074] This offers the advantage that the gas mixture flow can flow more evenly into the flow channels of the desublimation zone, since essentially the same hole area is present per projected flow channel, whereby the respective projected flow channel results from two adjacent projected flow channel walls.

[0075] In a preferred embodiment of the desublimator according to the invention, the desublimator has a horizontal longitudinal axis oriented perpendicular to the longitudinal axis of the flow channels of the desublimation zone (4), and the gas inlet distribution chamber (3) is arranged above the desublimation zone (4). This provides the advantage that during the loading process, the cooling of the gas mixture flow occurring in the flow channels of the desublimation zone causes the gas mixture to flow more intensively toward the gas outlet chamber due to the resulting convection effect.

[0076] In a preferred embodiment of the desublimator according to the invention, the flow channel walls are formed by the outer walls of a tube bundle, a finned tube, a finned tube bundle, a finned body, a honeycomb body, and / or a plate body. This offers the advantage that, during the loading process, the at least one gas component to be desublimated efficiently desublimates at the flow channel walls of the desublimation zone, and that the pressure loss across the desublimation zone is minimized during the loading process.

[0077] Another object of the invention is a method for operating a desublimator according to the invention.

[0078] In the method according to the invention for operating a desublimator according to the invention, during the loading process of the desublimator, the gas mixture flow containing at least one gas component to be desublimated flows in at the inlet at a mass flow of at least 0.01 kg / s, at a temperature in the range from above the desublimation temperature given at the existing pressure to 300 °C above the desublimation temperature of the at least one gas component to be desublimated at the existing pressure, and at an absolute pressure in the range from 0.1 to 10.00 bar, preferably in the range from 0.5 to 1.5 bar, particularly preferably in the range from 1.05 to 1.10 bar. The flow channel walls of the desublimation zone are cooled to a temperature in the range from 150 °C below the desublimation temperature given at the existing pressure to 1 °C below the desublimation temperature given at the existing pressure.The at least one gas component to be desublimated in the gas mixture flow desublimates at least partially within the desublimator. Preferably, the at least one gas component to be desublimated desublimates in the range of 10 to 100 wt. %, based on the at least one gas component of the gas mixture flow to be desublimated flowing in at the inlet. Particularly preferably, the at least one gas component to be desublimated desublimates in the range of 50 to 100 wt. %, based on the at least one gas component of the gas mixture flow to be desublimated flowing in at the inlet. If there are multiple gas components to be desublimated in the gas mixture flow, the ranges specified above refer to the respective gas component to be desublimated.

[0079] This results in the advantage that during the loading process, at least one gas component to be desublimated efficiently desublimates at the flow channel walls of the desublimation zone, and that the pressure loss across the desublimation zone is minimized. Furthermore, the gas mixture flows more evenly through the flow channels of the desublimation zone.

[0080] In a preferred embodiment of the method according to the invention for operating a desublimator according to the invention, the pressure loss between the inlet and the outlet of the desublimator during the loading process is a maximum of 80 mbar, preferably a maximum of 40 mbar, particularly preferably a maximum of 20 mbar.

[0081] This offers the advantage that the pressure drop does not become excessive during maximum load operation of the loading process. If the pressure drop does become excessive, the mass flow of the gas mixture at the inlet could decrease. In this case, a pump could be used as an alternative to achieve the desired mass flow of the gas mixture at the inlet. However, this poses the risk that the pump could become clogged with at least one gas component to be desublimated during operation and thus have to be shut down.

[0082] In a preferred embodiment of the method according to the invention for operating a desublimator according to the invention, after reaching a predetermined loading of the at least one desublimated gas component on the flow channel walls of the desublimator or after reaching a predetermined loading time, a melting process takes place, which comprises the following steps:

[0083] • Stop the supply of the gas mixture flow into the desublimator,

[0084] • Heating the flow channel walls of the desublimation zone to a temperature in the range from the desublimation temperature given at the existing pressure to 300 °C above the desublimation temperature of the at least one gas component to be desublimated given at the existing pressure, • Melting the at least one desublimated gas component in the desublimator to obtain a melt, and

[0085] • Removal of the melt from the desublimator, whereby the removal preferably takes place through an outlet nozzle on the housing wall of the gas outlet chamber.

[0086] This offers the advantage of a more efficient melting process. For example, scraping the desublimated gas component(s) from the flow channel walls of the desublimation zone is not necessary.

[0087] In a preferred embodiment of the method according to the invention for operating a desublimator according to the invention, after the melt has been removed from the desublimator, a recooling process takes place in which the flow channel walls of the desublimation zone are cooled to a temperature in the range from 150 °C below the desublimation temperature given at the existing pressure to 1 °C below the desublimation temperature given at the existing pressure.

[0088] This offers the advantage that the flow channels of the desublimation zone already have the required temperature for desublimation before the loading process. Thus, at least one gas component to be desublimated is efficiently separated from the gas mixture flow right at the beginning of the loading process.

[0089] In a preferred embodiment of the method according to the invention for operating a desublimator according to the invention, the at least one gas component to be desublimated contains predominantly phthalic anhydride, preferably only phthalic anhydride, in its mass fraction.

[0090] In a preferred embodiment of the method according to the invention for operating a desublimator according to the invention, the concentration of the at least one gas component to be desublimated in the gas mixture flow at the inlet is in the range from 0.001 to 50 wt.%, preferably in the range from 0.1 to 10 wt.%.

[0091] This results in the advantage that at least one gas component to be desublimated is efficiently separated from the gas mixture flow.

[0092] The invention is explained in more detail below with reference to the drawings. The drawings are to be understood as schematic representations. They do not represent a limitation of the invention, for example, with regard to specific dimensions or design variants. They show: Fig. 1: A drawing of a first exemplary embodiment of a desublimator according to the invention in longitudinal section.

[0093] Fig. 2: A drawing of the first exemplary embodiment of a desublimator according to the invention according to Fig. 1 in cross section.

[0094] Fig. 3: A drawing of a second exemplary embodiment of a perforated plate according to the invention. The holes in the perforated plate each have a diameter of 10 mm and a pitch of 24 mm.

[0095] Fig. 4: A drawing of a third exemplary embodiment of a perforated plate according to the invention. The holes in the perforated plate each have a diameter of 15 mm and a pitch of 36 mm.

[0096] Fig. 5: A drawing of a fourth exemplary embodiment of a perforated plate according to the invention. The holes in the perforated plate are elongated holes and have a short side of 10.0 mm and a long side of 19.8 mm. The hole pitch is 24 mm.

[0097] Fig. 6: A perspective view of a desublimator without a perforated plate according to a first comparative example, showing the velocities of the gas mixture flow along the longitudinal axis of the flow channels on the area shown at the beginning of the loading process. The area shown lies in the uppermost surface of the desublimation zone.

[0098] Fig. 7: A vector plot of the velocities of the gas mixture flow at the beginning of the loading process within a desublimator according to Fig. 6, which does not have a perforated plate, the vector plot being shown on the cross-sectional surface of the desublimator longitudinal section.

[0099] Fig. 8: A perspective view of a fifth exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3, wherein the velocities of the gas mixture flow in the direction of the longitudinal axis of the flow channels are shown on the area shown at the beginning of the loading process. Here, the area shown lies in the uppermost surface of the desublimation zone.

[0100] Fig. 9: A perspective view of a sixth exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3, wherein the velocities of the gas mixture flow in the direction of the longitudinal axis of the flow channels are shown on the area shown at the beginning of the loading process. Here, the area shown lies in the uppermost surface of the desublimation zone.

[0101] Fig. 10: A perspective view of a desublimator without a perforated plate according to a second comparative example, showing the velocities of the gas mixture flow along the longitudinal axis of the flow channels on the area shown at the beginning of the loading process. The area shown lies in the uppermost surface of the desublimation zone.

[0102] Fig. 11: A perspective view of a seventh exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3, wherein the velocities of the gas mixture flow in the direction of the longitudinal axis of the flow channels are shown on the area shown at the beginning of the loading process. Here, the area shown lies in the uppermost surface of the desublimation zone.

[0103] Fig. 12: A perspective view of an eighth exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3, wherein the velocities of the gas mixture flow in the direction of the longitudinal axis of the flow channels are shown on the area shown at the beginning of the loading process. Here, the area shown lies in the uppermost surface of the desublimation zone.

[0104] Fig. 13: A perspective view of a ninth exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3, wherein the velocities of the gas mixture flow in the direction of the longitudinal axis of the flow channels are shown on the area shown at the beginning of the loading process. Here, the area shown lies in the uppermost surface of the desublimation zone.

[0105] Fig. 14: A perspective view of a tenth exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3 in cross section, wherein the velocities on the surface shown are shown at the beginning of the loading process.

[0106] Fig. 15: A perspective view of an eleventh exemplary embodiment of the desublimator according to the invention with a perforated plate according to the invention according to Fig. 3 in cross section, wherein the velocities on the surface shown are shown at the beginning of the loading process.

[0107] List of reference symbols used:

[0108] 1 desublimator

[0109] 2 Entrance

[0110] 3 Gas inlet distribution room

[0111] 4 Desublimation zone

[0112] 5 Gas outlet room

[0113] 6 Outlet

[0114] 7 Housing wall 8 Perforated sheet

[0115] 9 Inlet area

[0116] 10 inlet nozzles

[0117] 11 Outlet nozzle

[0118] 12 outlet area

[0119] 17 Additional outlet nozzle with a drain valve

[0120] Amax distance between the inlet surface and the desublimation zone

[0121] A T Distance between the geometric center of gravity of at least one

[0122] Perforated plate and the desublimation zone

[0123] B Width of the desublimator

[0124] D equivalent diameter g gravity vector

[0125] H Height of the desublimator

[0126] L Length of the desublimator

[0127] Fig. 1 shows a first exemplary embodiment of a desublimator 1 according to the invention with a length L in longitudinal section, wherein the gravity vector g is represented by an arrow at the bottom right of Fig. 1 and the xy coordinate system is represented at the bottom left of Fig. 1. The desublimator 1 has a horizontal longitudinal axis perpendicular to the longitudinal axis of the flow channels of the desublimation zone 4. The desublimator 1 has an inlet 2 with an inlet nozzle 10 through which, during a loading process, a gas mixture flow containing at least one gas component to be desublimated flows into the gas inlet distribution chamber 3 of the desublimator 1. For this purpose, an inlet surface 9 is provided on the housing wall 7, wherein the housing wall 7 serves as the outer boundary of the desublimator 1. A desublimation zone 4 with temperature-controlled flow channel walls spaced the gas inlet distribution chamber 3 from a gas outlet chamber 5.The desublimation zone is connected to the gas inlet distribution chamber 3 such that, during the loading process, the gas mixture flow can flow from the gas inlet distribution chamber 3 to the desublimation zone 4. Furthermore, the desublimation zone 4 is connected to a gas outlet chamber 5 such that, during the loading process, the gas mixture flow can flow from the desublimation zone 4 to the gas outlet chamber 5. An outlet 6 is arranged at the gas outlet chamber 5 so that, during the loading process, the gas mixture flow can flow out of the desublimator 1. For this purpose, an outlet surface 12 is provided on the housing wall 7, with an outlet nozzle 11 arranged around the outlet surface 12. The desublimation zone 4 preferably has a volume in the range of 1 to 100 m³. 3 .

[0128] A perforated plate 8 is arranged in the gas inlet distribution chamber 3 so that the gas mixture flows more evenly through the flow channels during the loading process. The gas mixture should flow through as large a proportion of the total area of ​​all flow channel walls of the desublimation zone 4 as possible, so that the gas mixture flows from the gas inlet distribution chamber 3 toward the gas outlet chamber 5.

[0129] This provides the largest possible area for desublimation.

[0130] The maximum velocity at which the gas flows through the flow channels of the desublimation zone 4 should be as close as possible to the average value of the velocities through the flow channels to prevent rapid clogging of individual flow channels. Furthermore, backflow of the treated gas mixture from the gas outlet chamber 5 toward the gas inlet distribution chamber 3 should be avoided as much as possible to prevent a significant pressure loss across the desublimation zone 4. In this example, the perforated plate 8 according to the invention is arranged in the gas inlet distribution chamber 7 at a distance ΔT from the desublimation zone 4 in the range of 0.03 to 0.3 * ΔA. max, where Amax corresponds to the distance between the inlet surface 9 and the desublimation zone 4. The perforated plate 8 has a porosity of 15.7% and a hole pitch of 24 mm, with the hole pattern corresponding to equilateral triangles. Furthermore, the holes in the perforated plate are circular, and their respective hole diameters are 10 mm.

[0131] In general, the spacing between the holes of a perforated plate 8 should preferably follow the pattern of the flow channel walls in the desublimator. In the examples disclosed here, these are between 6 mm and 12 mm.

[0132] Other patterns may be appropriate, for example, if the distance between two adjacent perforated plates in the desublimator varies. In this case, the pattern can be adapted to the position of the channels. The equilateral triangle arrangement has the advantage of a small and more uniform distance between two holes in adjacent perforated plates.

[0133] In addition, there is also an additional outlet nozzle 17 with a drain valve, which can be a sealed closure cap, for example. During the loading process, the drain valve is closed, preventing any gas mixture from flowing out of the additional outlet nozzle 17. During a melting process, however, the drain valve is open, allowing the generated melt to flow out of the desublimator. Typically, this additional outlet nozzle 17 is located at the lowest point in the gas outlet chamber, allowing the melt to flow to the additional outlet nozzle 17 by gravity.

[0134] Fig. 2 shows a cross-section of the first exemplary embodiment of a desublimator 1 according to the invention according to Fig. 1, wherein the desublimator 1 has a height H and a width B. The zy coordinate system is shown at the bottom left of Fig. 2. The cross-section shows the housing wall 7, the gas inlet distribution chamber 3, the desublimation zone 4, the perforated plate 8 with its distance A. T to the desublimation zone 4, the maximum distance Amax, which is defined by the distance between the inlet surface 9 and the desublimation zone 4, the gas outlet space 5, the outlet surface 12 and the inlet surface 9 with a diameter D.

[0135] Fig. 3 shows a perforated plate 8 according to the invention with a hole diameter of 10 mm and a hole pitch of 24 mm, with three holes forming an equilateral triangle as a pattern. The parallel lines represent the flow channel walls. Thus, the holes are located between the flow channel walls when viewed perpendicularly from the gas inlet distribution chamber 3 onto the perforated plate.

[0136] Fig. 4 shows a perforated plate 8 according to the invention with a hole diameter of 15 mm and a hole pitch of 36 mm, with three holes forming an equilateral triangle as a pattern. The parallel lines represent the flow channel walls. Thus, the holes are located centrally above the flow channel walls when viewed perpendicularly from the gas inlet distribution chamber 3 onto the perforated plate.

[0137] Fig. 5 shows a perforated plate 8 according to the invention with elongated holes whose long side is 19.8 mm and whose short side is 10.0 mm. The perforated plate 8 has a hole pitch of 36 mm, with three holes forming an equilateral triangle as a pattern. The parallel lines represent the flow channel walls. Thus, the holes are located with an overlap between the flow channel walls when viewed perpendicularly from the gas inlet distribution chamber 3.

[0138] Examples

[0139] The following examples of the loading process of a desublimator are represented by numerical fluid mechanics simulations. Numerical fluid mechanics simulations are also often referred to as "computational fluid dynamics (CFD)". The software ANSYS Fluent was used for this purpose, which is available on the website ;-fluent (accessed on August 25, 2022). ANSYS Fluent is a comprehensive simulation software used for modeling, simulating, and optimizing fluid dynamic processes, systems, and components in industry.

[0140] The simulations in the following examples are based on a steady-state simulation using the RANS turbulence model. The default settings of the Fluent Solver version 22.1 are used. Example 1

[0141] A thermodynamic simulation of an embodiment of the method for operating a desublimator 1 according to the invention according to Fig. 1 was carried out in Fluent.

[0142] The length L of the desublimator 1 is 7.24 m, the width B of the desublimator 1 is 2.85 m, the height H of the desublimator 1 is 4.56 m, the height of the desublimation zone is 1.7 m, the diameter D of the circular inlet surface 9 is 0.79 m, the diameter of the circular outlet surface 12 is 0.79 m, the internal volume of the gas inlet distribution chamber is 23.8 m 3 and the internal volume of the gas outlet chamber is 24.9 m 3 .

[0143] The ratio between the inlet area of ​​the desublimation zone 4 and the distance between the inlet and outlet areas of the desublimation zone 4 is 13.1 [m 2 / m].

[0144] Desublimation zone 4 has a volume of 32.58 m 3 The surface area of ​​all flow channel walls in desublimation zone 4 is 5000 m 2 . This means that a cooling surface of 5000 m 2 before and for the melting process there is a heating surface of 5000 m 2 before.

[0145] In the simulation, however, the finned tubes are simplified due to the required computing power so that a porous zone represents the four finned tube bundles. The pressure loss across the flow channels of desublimation zone 4 is thus calculated efficiently. The porous zone is described in chapter 6.2.3 in the ANSYS Fluent User's Guide dated February 17, 2016, which is published by

[0146] The porous zone is described in more detail on the Computational Fluid Mechanics website provided by ANSYS, Inc., at "https: / / www.ansys.com / ." Furthermore, such a porous zone is also described on page 44 of the Computational Fluid Mechanics website. of Chemical Processes - Books (accessed on September 5, 2022).

[0147] In this case, the flow directions of the gas mixture flow within the flow channels, which would deviate from the longitudinal axis of the flow channels, are at least predominantly aligned by a corresponding pressure loss in such a way that these flow directions also point in the direction of the longitudinal axis of the flow channels.

[0148] The perforated plate 8 according to the invention is located directly on the uppermost surface of the desublimation zone. The distance ΔT between the perforated plate 8 and the desublimation zone is thus 0 mm.

[0149] The pressure drop of perforated plate 8 is set based on the detailed simulation of perforated plate 8 shown below in Fig. 3. Perforated plate 8 shown in Fig. 3 has a hole diameter of 10 mm and a hole pitch of 24 mm, with three holes forming an equilateral triangle. The porosity of perforated plate 8 is 15.7%.

[0150] The simulation produces the following results:

[0151] A gas mixture flow with a mass flow of 150 t / h, an absolute pressure of 1,086 bar, and a temperature of 178 °C is fed to the desublimator 1 through an inlet 2. The mass flow of the gas mixture flow contains PSA as the gas component to be desublimated at a concentration of 8 wt.%. Under the prevailing thermodynamic conditions, the density of the gas mixture flow is 4.4 kg / m 3 and the dynamic viscosity of the gas mixture flow is 2.5*10 -5 Pa*s. The housing wall has a temperature of 178 °C.

[0152] The area-averaged pressure loss caused by the perforated plate 8 is less than 100 Pa. The pressure loss between the inlet 2 and the outlet 6 of the desublimator 1 is 15.86 mbar.

[0153] The inflow area is 14 m 2from the gas inlet distribution chamber 3 to the gas outlet chamber 5. A backflow occurs in the remaining portion of the inlet area. The maximum velocity of the gas mixture flow through the desublimation zone 4 is 3.5 m / s, and the average velocity of the gas mixture flow through the desublimation zone 4 is 0.46 m / s.

[0154] The achieved uniform distribution of the gas mixture flow through the flow channels is evaluated based on the following flow simulation results:

[0155] Fig. 8 shows the inflow area of ​​the desublimation zone 4, wherein the velocities of the gas mixture flow are shown in the direction of the longitudinal axis of the flow channels at the beginning of the loading process, and wherein the inflow area is located in the uppermost surface of the desublimation zone 4. At the beginning of the loading process, the desublimation at the flow channel walls of the desublimation zone 4 takes place predominantly in an area located on the opposite side of the inlet surface 9. As the loading process progresses, the location of the desublimation shifts towards the inlet surface 9. The velocities whose velocity vectors are oriented in the direction of the main flow direction of the gas mixture flow through the flow channels of the desublimation zone 4 are shown in black if the magnitude of the velocity is greater than or equal to 10 m / s.The velocities whose velocity vectors are oriented in the opposite direction to the main flow direction of the gas mixture flow through the flow channels of the desublimation zone 4 are shown in white if the velocity magnitude is greater than 0 m / s. A comparison of Figures 6 and 8 shows that in a desublimator 1 according to the invention, the gas mixture flows through a larger area of ​​the desublimation zone 4 in the direction of the gas outlet chamber 5. In addition, the perforated plate 8 according to the invention ensures that the rear area of ​​the gas inlet distribution chamber 3 in the main flow direction has velocity directions oriented in the direction of the gas outlet chamber 5 across the entire width B of the desublimator 1. This avoids higher velocities in the flow channels of the desublimation zone 4, and the pressure loss across the desublimation zone 4 is correspondingly lower.A strong flow through individual flow channels would lead to rapid clogging. In extreme cases, this could even result in desublimation at the flow channel walls only partially occurring due to the high velocities of the gas mixture flow. A perforated plate 8 reduces excessive velocities and the resulting backflow in neighboring flow channels, thus preventing or at least partially preventing the aforementioned effects.

[0156] Example 2

[0157] A thermodynamic simulation of an inventive embodiment of the method for operating a desublimator 1 according to the invention as shown in Fig. 1 was carried out in Fluent. This Example 2 differs from Example 1 only in the material properties and the mass flow of the gas mixture flow. In this Example 2, a gas mixture flow with a mass flow of 30 t / h, an absolute pressure of 1,086 bar, and a temperature of 178 °C is fed to the desublimator 1 through an inlet 2. The mass flow of the gas mixture flow contains PSA as the gas component to be desublimated at a concentration of 3 wt. %, whereby the gas mixture flow has a molar mass of 29.7 g / mol. Under the existing thermodynamic conditions, the dynamic viscosity of the gas mixture flow is 2.26*10-5 Pa*s. The housing wall has a temperature of 178 °C.

[0158] The pressure loss caused by the perforated plate 8 is less than 10 Pa. The pressure loss between the inlet 2 and the outlet 6 of the desublimator 1 is 3.3 mbar.

[0159] The inflow area of ​​the desublimation zone 4 is shown in Fig. 9, where the velocities of the gas mixture flow in the direction of the longitudinal axis of the flow channels at the beginning of the loading process are shown, and where the inflow area is located in the uppermost surface of the desublimation zone 4. The inflow area is 14.7 m 2 from the gas inlet distribution chamber 3 to the gas outlet chamber 5. A backflow occurs in the remaining portion of the inlet area. The maximum velocity of the gas mixture flow through the desublimation zone 4 is 2.7 m / s, and the average velocity of the gas mixture flow through the desublimation zone 4 is 0.46 m / s.

[0160] At the beginning of the loading process, desublimation at the flow channel walls of the desublimation zone 4 predominantly takes place in an area located on the opposite side of the inlet surface 9. As the loading process progresses, the location of desublimation shifts toward the inlet surface 9.

[0161] The velocities whose velocity vectors are oriented in the direction of the main flow direction of the gas mixture flow through the flow channels of desublimation zone 4 are shown in black if the velocity magnitude is greater than or equal to 12 m / s. The velocities whose velocity vectors are oriented in the opposite direction to the main flow direction of the gas mixture flow through the flow channels of desublimation zone 4 are shown in white if the velocity magnitude is greater than 0 m / s.

[0162] From the comparison of the two Figures 8 and 9 it can be seen that, despite the different material properties of the gas mixture flow, the perforated plate 8 achieves a similar effect with regard to the even distribution of the gas mixture flow through the flow channels of the desublimation zone 4, whereby Fig. 8 is assigned to Example 1 and Fig. 9 to Example 2. In both Figures 8 and 9 the loading process takes place accordingly more evenly than in Comparative Example 1 with its associated Fig. 6. Only in the vicinity of the inlet surface 9 does an area exist in Figures 8 and 9 through which the flow flows in the opposite direction to the main flow direction.

[0163] Consequently, a perforated plate 8 according to the invention also reduces excessive velocities in the case of other material properties or mass flows of the gas mixture flow and thus also reduces backflows in adjacent flow channels.

[0164] It has hereby been demonstrated that the perforated plate 8 according to the invention achieves its effect of better uniform distribution through the flow channels of the desublimation zone 4 with different material properties of the gas mixture flow or with different mass flows of the gas mixture flow.

[0165] Example 8 Example 8 according to the invention corresponds to Example 2, whereby the porosity of the perforated sheet 8 is now 5%.

[0166] The inflow area is 17.04 m 2 from the gas inlet distribution chamber 3 to the gas outlet chamber 5. The pressure loss is 4.39 mbar across the desublimator and the maximum velocity is 0.65 m / s.

[0167] Fig. 11 shows that almost the entire inflow area is flowed from the gas inlet distribution chamber 3 to the gas outlet chamber 5.

[0168] Example 9

[0169] Example 9 according to the invention corresponds to Example 2, whereby the porosity of the perforated sheet 8 is now 20%.

[0170] The inflow area is 13.06 m 2 from the gas inlet distribution chamber 3 to the gas outlet chamber 5. The pressure loss is 3.25 mbar across the desublimator and the maximum velocity is 3.8 m / s.

[0171] Fig. 12 shows that, except for the front area, the entire inflow area is subjected to flow from the gas inlet distribution chamber 3 to the gas outlet chamber 5.

[0172] Example 10

[0173] Example 10 according to the invention corresponds to Example 2, whereby the porosity of the perforated sheet 8 is now 50%.

[0174] The inflow area is 10.47 m 2 from the gas inlet distribution chamber 3 to the gas outlet chamber 5. The pressure loss is 3.17 mbar across the desublimator and the maximum velocity is 6.2 m / s.

[0175] Fig. 13 shows that essentially only the rear half of the inflow area is flowed from the gas inlet distribution chamber 3 to the gas outlet chamber 5.

[0176] Example 11

[0177] Example 11 according to the invention corresponds to Example 2, with the distance AT between the perforated plate 8 and the desublimation zone 4 now being 24 mm. Since the diameter D of the circular inlet surface 9 remains 0.79 m, this corresponds to 0.03 * D.

[0178] Fig. 14 shows a cross-section through the desublimator, with the holes in the perforated plate 8 aligned with the flow channel walls. The flow can hardly be distributed between the perforated plate 8 and the desublimation zone 4, whereby the jets emanating from the holes in the perforated plate 8 are maintained and flow through the flow channel walls of the desublimation zone 4 with virtually no interference. Example 12

[0179] Example 12 according to the invention corresponds to Example 2, wherein the distance A T between the perforated plate 8 and the desublimation zone 4 is now 400 mm. Since the diameter D of the circular inlet surface 9 remains 0.79 m, this corresponds to 0.5 * D.

[0180] Fig. 15 shows a cross-section through the desublimator. The flow can be well distributed between the perforated plate 8 and the desublimation zone 4, whereby the jets originating from the holes in the perforated plate 8 become smaller with increasing distance from the perforated plate.

[0181] Conclusion for the above examples:

[0182] If the perforated plate 8 either lies directly on the desublimation zone 4 or is located at a close distance from the desublimation zone 4, the individual jets from the perforated plate 8 enter the flow channels of the desublimation zone 4 at an excessive speed. The average jet speed here is the ideal, homogeneous speed divided by the porosity. The lower the porosity, the greater the local velocity increase. At a porosity of 5%, this results in a factor of 20. These strong jets then, in turn, lead to backflow areas between the jets and poor flow distribution. Therefore, at low porosities, it is even more preferable to have a large distance between the perforated plate and the desublimation zone. At 50% porosity, a short distance is usually sufficient.If the perforated plate is too close to the inlet surface 9 and also has a low porosity, the "jet pump effect" can also lead to a reversal of the flow direction through the perforated plate 8 in the area of ​​the incoming jet.

[0183] Comparison example 1

[0184] Compared to Example 1, there is no perforated plate 8. All other features of desublimator 1, as well as the process parameters for the loading process, remained the same. Here, too, a simulation was performed using the Fluent software.

[0185] The achieved uniform distribution of the gas mixture flow through the individual flow channels is evaluated based on the following flow simulation results:

[0186] The pressure loss between inlet 2 and outlet 6 of desublimator 1 is 15.68 mbar. The desublimation zone 4 receives gas from the gas inlet distribution chamber 3 via an inflow area, whereby the inflow area corresponds to the uppermost surface of the desublimation zone 4.

[0187] The inflow area is 8.6 m 2 from the gas inlet distribution chamber 3 to the gas outlet chamber 5. A backflow occurs in the remaining portion of the inlet area. The maximum velocity of the gas mixture flow through the desublimation zone 4 is 13.4 m / s, and the average velocity of the gas mixture flow through the desublimation zone 4 is 0.46 m / s.

[0188] The inflow surface of the desublimation zone 4 is shown in Fig.6, where the velocities of the gas mixture flow at the beginning of the loading process are shown on the inflow surface shown in the direction of the longitudinal axis of the flow channels, and where the inflow surface is located in the uppermost surface of the desublimation zone 4.

[0189] At the beginning of the loading process, desublimation at the flow channel walls of the desublimation zone 4 predominantly takes place in an area located on the opposite side of the inlet surface 9. As the loading process progresses, the location of desublimation shifts toward the inlet surface 9.

[0190] The inflow surface exhibits a gradient between the central axis and the housing walls 7, whereby the gradient is determined by the uneven velocity distribution. Desublimation occurs particularly near the housing wall 7. In the area of ​​the inlet surface 9, hardly any desublimation occurs at the beginning of the loading process.

[0191] The velocities whose velocity vectors are oriented in the direction of the main flow direction of the gas mixture through the flow channels of desublimation zone 4 are shown in black if the velocity magnitude is greater than or equal to 10 m / s. The velocities whose velocity vectors are oriented in the opposite direction to the main flow direction of the gas mixture through the flow channels of desublimation zone 4 are shown in white if the velocity magnitude is greater than 0 m / s. Values ​​in the intermediate range are shown according to the scale shown in Fig. 6.

[0192] A vector plot of the velocity vectors of the gas mixture flow at the beginning of the loading process is shown inside the desublimator 1 in Fig. 7, with the vector plot being plotted on the section of the desublimator's longitudinal section. The length of the vectors is constant and thus independent of the velocity magnitude.

[0193] It can be seen that essentially in the left-hand area of ​​the desublimation zone 4, indicated by a rectangular frame, the gas mixture flows completely through the desublimation zone 4 toward the gas outlet chamber 5. The curved, dashed line in the desublimation zone 4 indicates the transition point at which the velocity direction through the flow channels of the desublimation zone 4 reverses. The further the curve descends, the less the gas mixture flows through the flow channels of the desublimation zone 4 toward the gas outlet chamber 5. In the area to the right of the curve, the gas mixture flows from the gas outlet chamber 5 through the flow channels of the desublimation zone 4 toward the gas inlet distribution chamber 3.

[0194] Comparison example 2

[0195] Compared to Comparative Example 1, Comparative Example 2 differs only in the material properties and the mass flow of the gas mixture. Here, too, a simulation was performed using the Fluent software.

[0196] In this comparative example 2, a gas mixture flow with a mass flow of 30 t / h, an absolute pressure of 1,086 bar, and a temperature of 178 °C is fed to the desublimator 1 through an inlet 2. The mass flow of the gas mixture flow contains PSA as the gas component to be desublimated at a concentration of 3 wt. %, whereby the gas mixture flow has a molar mass of 29.7 g / mol. Under the prevailing thermodynamic conditions, the dynamic viscosity of the gas mixture flow is 2.26*10-5 Pa*s. The housing wall has a temperature of 178 °C.

[0197] The achieved uniform distribution of the gas mixture flow through the individual flow channels is evaluated based on the following flow simulation results:

[0198] The pressure loss between inlet 2 and outlet 6 of desublimator 1 is 3.2 mbar.

[0199] The desublimation zone 4 is supplied with gas from the gas inlet distribution chamber 3 via an inflow surface, whereby the inflow surface corresponds to the uppermost surface of the desublimation zone 4.

[0200] The inflow area is 8.7 m 2from the gas inlet distribution chamber 3 to the gas outlet distribution chamber 5, through which the gas mixture flows. A backflow occurs in the remaining portion of the inflow area. The maximum velocity of the gas mixture flow through the desublimation zone 4 is 11.2 m / s, and the average velocity of the gas mixture flow through the desublimation zone 4 is 0.46 m / s. The inflow area of ​​the desublimation zone 4 is shown in Fig. 10, with the velocities of the gas mixture flow at the beginning of the loading process on the inflow area shown being shown in the direction of the longitudinal axis of the flow channels, and with the inflow area being located on the uppermost surface of the desublimation zone 4.

[0201] At the beginning of the loading process, desublimation at the flow channel walls of the desublimation zone 4 predominantly takes place in an area located on the opposite side of the inlet surface 9. As the loading process progresses, the location of desublimation shifts toward the inlet surface 9.

[0202] The inflow surface exhibits a gradient between the central axis and the housing walls 7, whereby the gradient is determined by the uneven velocity distribution. Desublimation occurs particularly near the housing wall 7. In the area of ​​the inlet surface 9, hardly any desublimation occurs at the beginning of the loading process.

[0203] The velocities whose velocity vectors are oriented in the direction of the main flow direction of the gas mixture through the flow channels of desublimation zone 4 are shown in black if the velocity magnitude is greater than or equal to 12 m / s. The velocities whose velocity vectors are oriented in the opposite direction to the main flow direction of the gas mixture through the flow channels of desublimation zone 4 are shown in white if the velocity magnitude is greater than 0 m / s. Values ​​in the intermediate range are shown according to the scale shown in Fig. 10.

[0204] The following are detailed simulations to investigate the influence of the exact perforated plate geometry depending on the design of the desublimation zone:

[0205] The detailed simulations were also calculated using the Fluent software. They each include only a portion of the perforated plate 8 with the flow channel walls of the desublimation zone 4 located underneath, as shown in Figs. 3 to 5. In addition to the inlet and outlet, symmetry boundary conditions are applied to the other outer boundaries of the computational model.

[0206] A simulation of the entire perforated plate 8 and accordingly also of the entire desublimation zone 4 would be too complex.

[0207] To demonstrate the potential for improving desublimation in desublimator 1, the heat transfer between the gas mixture flow and the flow channel walls was simulated in addition to the gas mixture flow. For each simulation, a gas mixture flow with an inlet velocity of 0.5 m / s at the inlet of the calculation model and an absolute pressure of 1.01325 bar at the outlet of the calculation model was set. The gas mixture flow has a temperature of 178 °C at the inlet of the calculation model. The flow channel walls are cooled to a temperature of 27 °C. Under the thermodynamic conditions present in the simulations, the density of the gas mixture flow is 0.81 kg / m 3 and the dynamic viscosity of the gas mixture flow is 2.26*10' 5 Pa*s.

[0208] The calculation model has the following design:

[0209] The length of the flow channel walls in the main flow direction is 0.35 m.

[0210] The distance between the flow channel walls is 11 mm, and the thickness of the flow channel walls is 1 mm. The aperture ratio, which corresponds to the ratio between the flowable inlet area and the total inlet area, is 91.67% at both the inlet and outlet.

[0211] Detailed simulation example 3:

[0212] Detailed simulation example 3 examines a perforated plate 8 according to the invention as shown in Fig. 3, with a hole diameter of 10 mm and a hole pitch of 24 mm, with three holes forming an equilateral triangle as a pattern. The porosity of the perforated plate 8 is 15.7%. The perforated plate 8 is arranged directly on the desublimation zone 4, whereby the distance between the perforated plate 8 and the desublimation zone 4 is exactly 0 mm.

[0213] Detailed simulation example 4:

[0214] Detailed simulation example 4 examines a perforated plate 8 according to the invention as shown in Fig. 3, with a hole diameter of 10 mm and a hole pitch of 24 mm, with three holes forming an equilateral triangle as a pattern. The perforation rate of the perforated plate 8 is 15.7%. The perforated plate 8 is spaced 40 mm from the desublimation zone 4.

[0215] Detailed simulation example 5:

[0216] Detailed simulation example 5 examines a perforated plate 8 according to the invention as shown in Fig. 4, with a hole diameter of 15 mm and a hole pitch of 36 mm, with three holes forming an equilateral triangle as a pattern. The porosity of the perforated plate 8 is 15.7%. The perforated plate 8 is arranged directly on the desublimation zone 4, whereby the distance between the perforated plate 8 and the desublimation zone 4 is exactly 0 mm. Detailed simulation example 6:

[0217] Detailed simulation example 6 examines a perforated plate 8 according to the invention as shown in Fig. 5 with elongated holes, each having a short and a long side. The short side of an elongated hole is 10 mm, and the long side of the elongated hole is 19.8 mm. The perforated plate 8 has a hole pitch of 36 mm, with three holes forming an equilateral triangle as a pattern. The porosity of the perforated plate 8 is 15.7%. The perforated plate 8 is arranged directly on the desublimation zone 4, whereby the distance between the perforated plate 8 and the desublimation zone 4 is exactly 0 mm.

[0218] Detailed simulation example 7:

[0219] Detailed simulation example 7 examines a perforated plate 8 according to the invention as shown in Fig. 5 with elongated holes, each having a short and a long side. The short side of an elongated hole is 10 mm, and the long side of the elongated hole is 19.8 mm. The perforated plate 8 has a hole pitch of 36 mm, with three holes forming an equilateral triangle as a pattern. The porosity of the perforated plate 8 is 15.7%. The perforated plate 8 is spaced 40 mm from the desublimation zone 4.

[0220] Results of the detailed simulations:

[0221] The reference for the detailed simulation examples recorded in Table 1 is perforated plate 8 according to detailed simulation example 3, with a hole diameter of 10 mm and a hole pitch of 24 mm. Perforated plate 8 is positioned directly on desublimation zone 4, resulting in a distance of exactly 0 mm between perforated plate 8 and desublimation zone 4.

[0222] Table 1: Evaluation of the detailed simulation examples 3 to 7. All values ​​are relative to the values ​​of detailed simulation example 3. Here, "aw-uni-alpha" is the area-related "uniformity index" of the heat transfer coefficient. The relative aw-uni-alpha values ​​in Table 1 correspond to the ratio between the "uniformity index" of the heat transfer coefficient of the respective detailed simulation example and the "uniformity index" of the heat transfer coefficient according to Detailed Simulation Example 3.

[0223] The larger this value is, the more uniform the desublimation takes place on the flow channel walls and thus the desublimator 1 can be operated longer and accordingly a larger amount of the desublimating gas component can be deposited on the flow channel walls.

[0224] Here, “T mw, outlet“ of the mass-averaged temperature of the gas mixture flow at the outlet of the desublimation zone 4. The relative “T m The “w, outlet” values ​​in Table 1 represent the ratio between the mass-averaged temperature of the gas mixture flow at the outlet of the desublimation zone 4 of the respective detailed simulation example and the mass-averaged temperature of the gas mixture flow at the outlet of the desublimation zone 4 according to the detailed simulation example 3. The lower this value, the better it is for the desublimation process, since more heat of the gas mixture is transferred to the flow channel walls.

[0225] Here, “dT mw, miet to outlet“ of the difference between the mass-averaged temperature of the gas mixture flow at the inlet of the desublimation zone 4 and the mass-averaged temperature of the gas mixture flow at the outlet of the desublimation zone 4. The relative “dTmw, miet to outlet” values ​​in Table 1 represent the ratio between the “dT mw , rent to outlet“ value of the respective detailed simulation example and the “dT mw , rent to outlet“ value of the detailed simulation example 3. The larger this value, the better it is for the desublimation process, since more heat of the gas mixture is transferred to the flow channel walls.

[0226] Here, “Pj n “ the absolute pressure at inlet 2 of desublimator 1.

[0227] The relative “Pj n“ Values ​​in Table 1 represent the relationship between the absolute pressure at inlet 2 of desublimator 1 of the respective detailed simulation example and the absolute pressure at inlet 2 of desublimator 1 according to detailed simulation example 3. The lower the value, the better it is for the desublimation process, as less pressure loss occurs in desublimator 1. The specific values ​​of detailed simulation example 3 are:

[0228] Conclusion:

[0229] Thus, the perforated plate 8, spaced 40 mm from the desublimation zone 4, according to Detailed Simulation Example 4, is considered the preferred embodiment. This perforated plate 8 has circular holes with a hole diameter of 10 mm and a hole pitch of 24 mm, with three holes forming an equilateral triangle as a pattern. The porosity of the perforated plate 8 is 15.7%.

[0230] This perforated plate 8 is best suited for installation in the desublimator 1, as the pressure loss is low and the mass-averaged temperature of the gas mixture flow at the outlet of the desublimation zone 4 is significantly lower than in the detailed simulation examples 3, 5, 6, and 7. The "aw-uni-alpha" value is also greater than 1, which means that desublimation at the flow channel walls occurs more uniformly than in the detailed simulation examples 3 and 5.

Claims

Patent claims 1. A discontinuously operated desublimator (1) for removing at least one gas component to be desublimated from a gas mixture flow, comprising a housing wall (7) as the outer boundary, an inlet (2) on the housing wall (7) for feeding the gas mixture flow into the desublimator (1), an outlet (6) on the housing wall (7) for discharging the treated gas mixture flow from the desublimator (1), a desublimation zone (4) with temperature-controlled flow channel walls, wherein the flow channel walls are temperature-controlled such that during a loading process, the at least one gas component to be desublimated desublimates on the flow channel walls, and that during a subsequent melting process, the at least one gas component desublimated in the loading process melts on the flow channel walls, a gas inlet distribution chamber (3) located between the inlet (2) and the desublimation zone (4), and a gas outlet chamber (5),which is located between the outlet (6) and the desublimation zone (4), characterized in that, • at least one first perforated plate (8) is arranged in the gas inlet distribution chamber (3) for the uniform distribution of the gas mixture flow through the flow channels resulting from the flow channel walls of the desublimation zone (4), • whose geometric center of gravity is a distance (A T ) to the desublimation zone (4) in the range from 0 to A ma x, preferably in the range of 0 to 0.5 * A ma x , and particularly preferably in the range from 0.03 to 0.3 * A ma x, where A ma x corresponds to the distance between the inlet surface (9) of the inlet (2) and the desublimation zone (4), and • wherein the at least first perforated plate (8) has a porosity in the range from 5 to 50%, preferably in the range from 10 to 30%, particularly preferably in the range from 10 to 20% and most particularly preferably in the range from 5 to 20%.

2. Desublimator (1) according to claim 1, wherein the at least first perforated plate (8) extends in its width up to the two opposite housing side walls (7) of the desublimator (1) and preferably has a distance of Range of 0 to 10 mm and particularly preferably a distance in the range of 0 to 1 mm.

3. Desublimator (1) according to one of claims 1 or 2, wherein the at least first perforated plate (8) covers the entire desublimation zone (4) and has a distance from the walls of the desublimator in the range of 0 to 10 mm, preferably in the range of 0 to 1 mm.

4. Desublimator (1) according to one of the preceding claims, wherein, when several perforated plates are present, a distance between the respective adjacent perforated plates in the range of 0 to 0.50 * A max , preferably in the range of 0 to 0.25* A ma x, where A max corresponds to the distance between the inlet surface (9) and the desublimation zone (4).

5. Desublimator (1) according to one of the preceding claims, wherein the holes of the at least first perforated plate (8) have different equivalent diameters, wherein the equivalent diameter corresponds to the diameter of a circle of equal area, and wherein the equivalent diameter of the individual holes is preferably in the range from 0.3 to 50.0 mm, particularly preferably in the range from 1.0 to 25.0 mm and most particularly preferably in the range from 5.0 to 20.0 mm.

6. Desublimator (1) according to claim 5, wherein the holes of the at least first perforated plate (8) which are located at a distance from the inlet surface (9) in the range from 0.0 mm to L / X mm have a larger equivalent diameter than the more widely spaced holes of the perforated plate (8), where L corresponds to the length of the longitudinal axis of the gas inlet distribution space (3) and X has a value in the range from 1.1 to 10.0 * L.

7. Desublimator (1) according to one of the preceding claims, wherein at least the first perforated plate (8) has circular, elongated, elliptical, oval, rectangular or polygonal holes.

8. Desublimator (1) according to one of the preceding claims, wherein the number of holes of the at least first perforated plate (8) is in the range of 100 to 15000 per m 2 -Perforated sheet surface, preferably in the range of 1000 to 4000 per m 2 -perforated sheet surface, and the holes preferably correspond to the pattern of an equilateral triangle.

9. Desublimator (1) according to one of the preceding claims, wherein the holes of the at least first perforated plate (8) have a hole pitch in the range of 5 to 50 mm, preferably in the range of 20 to 30 mm.

10. Desublimator (1) according to one of the preceding claims, wherein several holes, preferably most of the holes, particularly preferably all of the holes, of the at least first perforated plate (8) are arranged such that the flow channel walls projected perpendicularly onto the plane of the at least first perforated plate (8) form a pattern with the geometric centers of gravity of the holes, wherein in the pattern one of the projected flow channel walls overlaps with the nearest geometric center of gravity of the corresponding hole or has a maximum distance of up to 0.50 * D Mit or with the nearest geometric center of gravity of the corresponding hole at a distance of 0.50 * DMÜ, where DIM corresponds to the equivalent diameter geometrically averaged over all flow channels, and where each individual equivalent diameter corresponds to a circle having the same area as the respective flow channel and each individual equivalent diameter is dimensioned at the inlet of the desublimation zone (4).

11. Desublimator (1) according to one of the preceding claims, wherein the desublimator (1) has a horizontal longitudinal axis oriented perpendicular to the longitudinal axis of the flow channels of the desublimation zone (4), and the gas inlet distribution space (3) is arranged above the desublimation zone (4).

12. Desublimator (1) according to one of the preceding claims, wherein the flow channel walls are provided by the outer walls of a tube bundle, a finned tube, a finned tube bundle, a lamellar body, a honeycomb body and / or a plate body.

13. A method for operating a desublimator (1) according to one of the preceding claims, wherein during the loading process of the desublimator (1), the gas mixture flow containing at least one gas component to be desublimated flows in at the inlet (2) at a mass flow of at least 0.01 kg / s, at a temperature in the range from above the desublimation temperature given at the existing pressure to 300 °C above the desublimation temperature of the at least one gas component to be desublimated at the existing pressure, and at an absolute pressure in the range from 0.1 to 10.00 bar, preferably in the range from 0.5 to 1.5 bar, particularly preferably in the range from 1.05 to 1.10 bar, the flow channel walls of the desublimation zone (4) are cooled to a temperature in the range from 150 °C below the desublimation temperature given at the existing pressure to 1 °C below the desublimation temperature given at the existing pressure become, and the at least one gas component to be desublimated in the gas mixture flow is at least partially desublimated, preferably in the range from 10 to 100 wt.%, based on the at least one gas component of the gas mixture flow to be desublimated flowing in at the inlet (2), and particularly preferably in the range from 50 to 100 wt.%, based on the at least one gas component of the gas mixture flow to be desublimated flowing in at the inlet (2).

14. The method according to claim 13, wherein during the loading process the pressure loss between the inlet (2) and the outlet of the desublimator (1) is a maximum of 200 mbar, preferably a maximum of 80 mbar and particularly preferably a maximum of 20 mbar.

15. The method according to claim 13 or 14, wherein the at least one gas component to be desublimated contains predominantly phthalic anhydride, preferably only phthalic anhydride, in its mass fraction.

Images