Apparatus and method for improved coolant circulation in microstructured reactors

Abstract

The invention relates to apparatuses and methods for improved coolant circulation in (micro-)structured reactors.

Description

[0001] DEVICE AND METHOD FOR IMPROVED COOLANT CIRCULATION IN MICRO-STRUCTURED REACTORS

[0002] All documents cited in the present application are incorporated in their entirety by reference.

[0003] The present invention relates to devices and methods for improved coolant circulation in (micro-)structured reactors.

[0004] State of the art:

[0005] In (micro)structured reactors, solid catalysts can be introduced as layers or as particle fillings. Such reactors are typically used for fast, high-energy reactions. The layered structure—alternating levels with flow of reaction medium and heat transfer medium—ensures efficient heat input and output, allowing the reaction to operate as close as possible to the target temperature. This is particularly effective when the reactor uses a coolant close to its boiling point on the cooling side, ensuring that at least a portion of the coolant evaporates as it passes through the reactor. This process utilizes the constant temperature of the coolant and the high heat transfer coefficient during phase transitions.

[0006] From an energy perspective and for reasons of isothermity within the reactor, preheating as close as possible to the boiling point of the coolant is advantageous. This is described, among other things, in US2013 / 0165536 Al, where a high velocity in the microchannel of > 10 cm / s enables partial evaporation over a length of more than 25 cm. In this case, the coolant channel is oriented 50% horizontally and orthogonally to the reaction coordinate. Maintaining the coolant temperature as close as possible to the boiling point is also beneficial from an energy perspective and for reasons of isothermity within the reactor when using reactors according to existing patent WO 2017 / 013003, since the supply channel of the parallelized evaporation structures is also perpendicular to the reaction coordinate.

[0007] The parallelization of reactors, including microstructured reactors, is well-documented in the literature for constructing plants with higher production capacity. Parallelization with regard to the distribution of the reaction stream is described, for example, in US6149882, WO 97 / 32208, DE 198 09 477, WO 99 / 41005, DE 198 06 848, WO 00 / 51720, and DE 601 08 482 T2. US9822049 further describes a common closed-loop coolant system, where the phase transition of a coolant is used for cooling. Crucially, this document states that heat removal from all reactors occurs in a common steam drum, while pressure control is implemented downstream of each reactor in the two-phase coolant to precisely control the reaction progress in each reactor. Further examples of the state of the art could be DE 11 2015 0014 756 T5 or DE 11 2012 003 021 T5.

[0008] Key challenges in the parallelization of reactors that have not been satisfactorily addressed by current technology include the following:

[0009] 1) If catalysts of different ages are used—in the extreme case, a fresh, highly active catalyst and a catalyst that has been in the reactor for several years and has already deactivated—significantly different pressures are required in the respective coolant streams. For example, in the Fischer-Tropsch synthesis, 15 bar and 30 bar are required, corresponding to boiling points of 198°C and 234°C, respectively. If heat extraction occurs after the streams are combined (for example, as in US9822049), the maximum available coolant temperature for recuperation with incoming coolant in the reactors is determined by the lowest pressure in the respective streams. Furthermore, the two-phase mixture cools down after pressure adjustment in the streams operating at higher pressures.Therefore, raising the coolant temperature to boiling point after the pump(s) and before entering the reactors must be powered by another energy source, which makes the process less economical. 2) Pressure control of a two-phase mixture is virtually impossible with regular control valves without pressure pulsations; therefore, the combination described in US9822049 is not advantageous.

[0010] 3) If heat extraction is performed from a two-phase coolant, the surface area required in the relevant heat exchanger increases due to the larger overall volume flow rate. Depending on the temperature of the second fluid used for heat extraction, the already liquid portion of the coolant may become subcooled. If the liquid fraction in the coolant is high after passing through the reactors, there is an increased need to raise the temperature of the recooled, liquid coolant before it re-enters the reactors.

[0011] There are currently no solutions that can satisfactorily address these challenges.

[0012] Therefore, based on the known state of the art, there is still a considerable need to improve the current state of the art, especially with regard to the three specifically mentioned challenges.

[0013] Task:

[0014] The object of the present invention was therefore to overcome the disadvantages of the prior art described above and to provide devices and methods which no longer exhibit these problems, or at least only to a significantly lesser extent.

[0015] In particular, more efficient methods and equipment should be made available.

[0016] Further tasks arise for the expert when considering the requirements and from the following description.

[0017] Solution:

[0018] These and other problems that arise for a person skilled in the art from the present description are solved by the items described in the independent claims. Preferred and particularly advantageous embodiments are described in the dependent claims and the following description.

[0019] Detailed description of the invention:

[0020] Within the scope of the present invention, all quantity specifications, unless otherwise stated, are to be understood as weight specifications.

[0021] Within the scope of the present invention, the term "ambient temperature" means a temperature of 20°C. Unless otherwise specified, temperature readings are in degrees Celsius (°C).

[0022] Unless otherwise stated, the reactions or process steps listed are carried out at ambient pressure (=normal pressure / atmospheric pressure), i.e. at 1013 mbar.

[0023] Pressure specifications within the scope of the present invention, unless otherwise stated, mean absolute pressure specifications, i.e., x bar (i.e., without a subscript) means x bar absolute (bar). a ) and not x bar gauge.

[0024] The present invention relates in a first essential aspect to a device for carrying out exothermic reactions, comprising at least one microreactor based on at least two superimposed reactor subunits, wherein each reactor subunit comprises at least one, or exactly one, reaction layer and at least one, or exactly one, cooling layer, and wherein each reactor subunit is provided with its own coolant inlet and its own coolant outlet, wherein each reactor subunit is assigned as separate components a first heat exchanger, a first phase separation device for dividing the coolant flow, a first control device for pressure control to the desired boiling pressure for the cooling water supply, and a second control device for controlling the liquid level in the first phase separation device.wherein the first heat exchanger (responsible only for this reactor subunit) for the recovery of heat contained in the discharged coolant stream (especially preferably against the cooling water supply to the reactor) is connected downstream of the coolant discharge of the respective reactor subunit; connected downstream of this first heat exchanger is the first phase separation device for splitting the coolant stream into a gas phase stream (vapor phase stream) and a liquid phase stream, wherein the first control device, in particular a pressure control device, is connected in the line for the gas phase stream leading out of the respective first phase separation device.for pressure control to the desired boiling pressure (boiling pressure corresponds to reaction temperature according to the Tp diagram) for the respective cooling water supply, and in the line for the liquid phase flow leading out of the respective first phase separation device, the respective second control device for controlling the level in the first phase separation device is arranged; the lines for the gas phase flows originating from the first phase separation devices lead downstream of the first control device into a device for combining the gas phase flows corresponding to the number of reactor subunits, from which a combined gas phase flow is then derived; downstream of the device for combining the gas phase flows, a second heat exchanger is arranged, which is configuredto extract heat derived from the combined gas phase stream for use in other applications; downstream of the second control device for regulating the level in the first phase separation device, a device for combining the liquid phase streams corresponding to the number of reactor subunits is located, from which a combined liquid phase stream is then derived; downstream of the second heat exchanger and the device for combining the liquid phase streams corresponding to the number of reactor subunits, a device for combining the two gas and liquid phase streams (resulting from the respective gas phase streams and the respective liquid phase streams, and now each liquid) and combining them into a combined coolant stream is located; downstream of the device for combining, a recirculation device, preferably a pump, is configuredthe combined coolant flow is returned as a return coolant flow; downstream of the return device, a device for dividing the return coolant flow into coolant partial flows corresponding to the number of reactor subunits is located, and then the coolant partial flows are fed via the respective first heat exchanger, wherein the coolant is heated in the respective first heat exchanger to (the desired) supply temperature, preferably close to the boiling point, particularly preferably 1 to 20°C, particularly preferably 1 to 8°C, below the boiling point of the coolant, into the coolant inlet of the respective reactor subunit.

[0025] It should be noted that the gas phase stream may be partially or completely condensed after passing through the second heat exchanger. For the sake of simplicity, however, it will continue to be referred to as a gas phase stream (until it merges with the liquid phase stream from the first phase separation device); firstly, because it may still be (partially) gaseous after the second heat exchanger if heat extraction is low, and secondly, to distinguish it from the liquid phase stream. If necessary, further condensation can take place downstream, as described below.

[0026] In preferred embodiments of the invention, the pressure control for the reactor is achieved on the gas phase stream, while the liquid fraction is continuously discharged according to the level in the vessel. The gas phase stream is then completely condensed in the subsequent second heat exchanger. In this embodiment, a pressurized buffer vessel can be arranged upstream of the return pump, from which the return pump draws its gas. In further preferred embodiments, gas (N₂ or other inert gas) can be added to or removed from the pressurized buffer vessel. This is because the fill level in the pressurized buffer vessel changes when evaporation begins in the reactor and controls the overall pressure level in the circuit.Since the device of the present invention represents a closed circuit, a pressure increase can occur if steam suddenly arises from a liquid-filled system; this can be countered by the addition or removal of gas, so that this addition or removal of gas, via gas inlets and outlets configured for this purpose in these variants, is provided as a control step or control device.

[0027] The pressure in the reactor is ultimately influenced by all components; according to the invention, the control is preferably not achieved by means of the feedback device (i.e., in particular not by speed control of a pump as a feedback device).

[0028] In preferred embodiments of the present invention, a third heat exchanger for pre-cooling the combined coolant flow against a heat-receiving substance (i.e., coolant, preferably water, air or similar, in particular water), in particular with simple mass flow control, is arranged between the merging device and the return device as a further component in the course of the combined coolant flow.

[0029] In preferred embodiments of the present invention, a second phase separation device is arranged upstream of the recirculation device, which is preferably configured to recool the combined coolant flow by controlling the amount of coolant supplied to the maximum inlet temperature specified by the downstream recirculation device.

[0030] At this point in the circuit, the coolant is therefore completely liquid, meaning the gas phase(s) are / are completely condensed. If the coolant is already completely condensed, i.e., completely liquid, before this point, the third heat exchanger, the second phase separation device, or the (pressurized) buffer tank can potentially be omitted. According to the invention, the third heat exchanger is used particularly when there is a risk that the coolant is still too hot, that a vapor phase is formed due to its expansion, or that cavitation is likely due to the suction effect of the downstream recirculation device (pump). In further embodiments of the present invention, the third heat exchanger can be switched on and off in a controlled manner.

[0031] In preferred embodiments of the present invention, the device comprises, between the device for dividing the return coolant flow into the number of reactor subunits corresponding to the number of coolant partial flows and the respective first heat exchanger, a third control device assigned to the respective reactor subunit, which is configured to direct the coolant partial flows via a respective bypass line, bypassing the first heat exchanger, directly into the coolant inlet, in the event that the temperature of the coolant flow is too close to the boiling temperature of the coolant.

[0032] This device component or step serves to prevent excessively hot coolant from entering the respective reactor subunit, because the already hot coolant would be heated even further by the first heat exchanger, so that (there is a risk that) it would already be present as a two-phase mass flow under boiling conditions; this would drastically reduce the cooling efficiency.

[0033] In preferred embodiments of the present invention, the second heat exchanger is configured to transfer some of the heat contained in the gas phase stream via indirect contact to a heat-receiving substance (i.e., a coolant), preferably water, in particular steam, for the operation of a reverse water-gas shift reaction.

[0034] In preferred embodiments of the present invention, the device is configured to use the heat extracted via the second heat exchanger for other purposes, such as steam generation, in particular for the generation of accompanying water for a rWGS, or for desorption of CO2 from a direct air capture plant or other uses, such as general heat applications.

[0035] In some preferred embodiments of the present invention, a further control device is located between the coolant return device and the device for dividing the return coolant flow into coolant partial flows corresponding to the number of reactor subunits. This control device sets a pressure that then enables division into the individual coolant partial flows if the pressure of the return coolant flow is insufficient or too high.

[0036] In preferred embodiments of the present invention, the device does not include any electrical heating devices that are active during continuous operation or operation.

[0037] One advantage of the device or method according to the invention is that no electric heating devices are required during continuous operation (running operation, normal operation, or regular operation). However, in some variants, it may be preferable to implement electric heating devices to bring the circuit to the "starting temperature" (i.e., the coolant to preferably 1 to 20°C, particularly preferably 1 to 8°C below boiling point) during commissioning or starting. According to the invention, no electric heating devices are required during continuous operation (running operation, normal operation, or regular operation). It is also possible, accordingly, not to implement any electric heating devices at all and to bring the circuit to the "starting temperature" during commissioning or starting.to start the cycle by using other known methods (for example, using the heat from other processes or solar heat) to bring it up to temperature, or for example, to only temporarily install electric heating devices and then remove them again.

[0038] In some embodiments of the present invention, it is possible to combine gas phase streams (vapor phase stream) and liquid phase streams originating from several respective reactor subunits before the second heat exchanger or before the merging device, and then to return the combined coolant as a whole and only divide it back into partial streams before introducing it into the respective reactor subunits.

[0039] In some embodiments of the present invention, at least one flow indicator / flow control device and / or at least one pressure indicator / pressure control device can be arranged upstream of the third control device in the flow direction. The present invention is based on the fact that the reactor subunits can operate at different pressures in the boiling water circuit (depending on the respective conditions in the respective reactor subunit, for example, catalyst activity). For this purpose, the recuperation of coolant upstream of the reactor, up to the pressure control point, is carried out separately for the respective reactor subunits. The extraction of heat for external use is simple, i.e., with combined coolant flows comprising coolant from several, preferably all, reactor subunits, as is the recirculation device (pump) for the (combined) coolant.

[0040] The present invention relates in a second essential object to a method for boiling water cooling in devices for carrying out exothermic reactions, in particular the devices according to the invention, wherein the device comprises at least one microreactor based on at least two superimposed reactor subunits, wherein each reactor subunit comprises at least one reaction layer and at least one cooling layer, and wherein each reactor subunit is provided with its own coolant inlet and its own coolant outlet, and wherein each reactor subunit is assigned as separate components a first heat exchanger, a first phase separation device for dividing the coolant flow, a first control device for pressure control to the desired boiling pressure for the cooling water supply, and a second control device for controlling the liquid level in the first phase separation device, and the method comprises steps i) to vi).comprising, wherein i) the coolant stream discharged from the coolant outlet of the respective reactor subunit is subjected in the respective first (i.e., solely for that) heat exchanger to the recuperation of contained heat (against the cooling water supply to the reactor); ii) subsequently, in the respective first phase separation device, the respective coolant stream is split into a gas phase stream (vapor phase stream) and a liquid phase stream, each of the two partial streams discharged from the respective first phase separation device being subjected to individual pressure control; iii) the gas phase streams originating from the first phase separation device are combined downstream of its pressure control device via a device for combining the gas phase streams corresponding to the number of reactor subunits into a combined gas phase stream; iv) downstream of this, the combined gas phase stream is transferred via a second heat exchangerHeat is extracted from the gas phase stream and extracted for other applications; v) the liquid phase streams originating from the first phase separation device are combined downstream of its pressure control device via a device for combining the liquid phase streams corresponding to the number of reactor subunits into a combined liquid phase stream; vi) downstream of the second heat exchanger and the device for combining the liquid phase streams corresponding to the number of reactor subunits, gas phase streams and liquid phase streams are combined and merged into a coolant stream; viii) the combined coolant stream is then returned as a return coolant stream by means of a recirculation device, preferably a pump; ix) the return coolant stream is divided into coolant partial streams corresponding to the number of reactor subunits via a device for dividing the return coolant stream; x) thenThe coolant partial flows corresponding to the number of reactor subunits are heated via the first heat exchanger to (the desired) supply temperature, preferably close to the boiling point, particularly preferably 1 to 20°C, particularly preferably 1 to 8°C, below the boiling point of the coolant, and returned to the coolant inlet of the respective reactor subunit.

[0041] In preferred embodiments of the present invention, between steps vi) and viii) step vii) pre-cooling of the combined coolant flow in a third heat exchanger against a second coolant (water, air or similar), in particular with simple mass flow control, takes place.

[0042] In preferred embodiments of the present invention, the second heat exchanger transfers a portion of the heat contained in the gas phase stream via indirect contact to a coolant, preferably water, in particular steam, for the operation of a reverse water-gas shift reaction.

[0043] In preferred embodiments of the present invention, the heat extracted via the second heat exchanger is used for other purposes, such as steam generation, in particular for the generation of accompanying water for a rWGS, or for desorption of CO2 from a direct air capture plant or other uses, such as general heat applications.

[0044] In preferred embodiments of the present invention, in which the steam coming from the first phase separation devices is used as process steam for other applications (i.e., extracted / drained from the system), the difference in coolant volume can be replaced by fresh water, which can be added to the liquid phase stream coming directly from the first phase separation device, downstream of the second heat exchanger to the coolant stream coming from the second heat exchanger (wholly or partially condensed gas phase stream), or in the device for combining the gas and liquid phase streams. In preferred embodiments of the devices or the method according to the invention, cooling in the microreactors takes place in cross-flow or counter-flow, particularly preferably in counter-flow.

[0045] Last but not least, the present invention relates to the use of the device according to the invention for Fischer-Tropsch reactions or methanol synthesis.

[0046] The problems described above, in particular the three specifically listed challenges, are solved by the devices and methods (guidelines) according to the invention, especially as follows:

[0047] 1) In the present invention, recuperation for preheating takes place directly after the coolant flows through each reactor sub-stream, i.e., after each individual reactor. This ensures that the incoming coolant temperature is preheated close to the boiling point. In this way, electric preheaters are unnecessary during normal operation or under steady-state conditions. A temperature between 1°C and 5°C lower than the boiling point can be guaranteed in each sub-stream. By controlling the sub-stream upstream of the recuperative heat exchanger in the inlet of the respective reactor sub-unit, this range can be extended, preferably to up to 8°C below the boiling point. Since each reactor has a pressure drop for the coolant of a maximum of 0.5 bar to 1 bar, and the boiling point drops by approximately 2°C in this process, it is also ensured that the boiling point is not exceeded during preheating.

[0048] 2) After each recuperation cycle, the coolant undergoes gas-liquid separation, with level control ensuring a pulsation-free pressure setting across the gas phase section. Despite the formation of a two-phase mixture, the liquid discharged from the first phase separation unit can be mixed with the condensed portion of the coolant upon expansion to the lowest pressure in the combined coolant circuit. Alternatively, if the steam is used as process steam for other applications, it can be replaced with fresh water, mixed, and pumped back to the reactors. To prevent vaporous components in the pump's feed line, the mixed stream is additionally cooled with coolant to the maximum inlet temperature specified by the pump (i.e., below the temperature at which no cavity problems occur or which the installed components can withstand) by means of flow control.From the steam extracted during phase separation, at least 70%, and usually even over 80%, of the total heat output released by the reactors can be transferred to other trades.

[0049] The present invention differs from the prior art in particular by a combination of the following features, which is not known from the prior art: individual recuperation in the coolant partial stream of each reactor subunit; pressure control in each coolant partial stream after gas-liquid separation in each coolant partial stream;

[0050] Extraction of the reaction heat contained in the dry steam for other trades in a common heat exchanger; optionally pre-cooling of the jointly recirculated liquid phase of the coolant before the pump with simple mass flow control of a second coolant.

[0051] With the devices and methods according to the invention, it is therefore possible to work considerably more efficiently compared to the prior art.

[0052] The devices and methods according to the invention offer several significant advantages over the prior art, some, but not all, of which are the following:

[0053] Maximizing the coolant supply temperature (close to the boiling point) in each partial stream without risk of exceeding the boiling point and without additional energy (only using reactor waste heat) through individual recuperation in each coolant partial stream; pulsation-free pressure control in each partial stream through gas-liquid separation upstream of pressure control; maximum utilization of the reaction heat through heat transfer from a common heat exchanger for the vapor phase; targeted pre-cooling of the jointly recirculated liquid phase upstream of the pump.

[0054] The person skilled in the art can, within the scope of their general expertise, determine the exact design of the described devices, insofar as these are not explicitly described in this description, such as size, wall thicknesses, materials, etc., according to the reaction conditions intended for a specific reaction.

[0055] Insofar as parts or the entire device are described as "consisting of" in the description of the devices according to the invention, this is to be understood as referring to the aforementioned essential components. This does not exclude obvious or inherent parts such as pipes, valves, screws, housings, measuring devices, storage containers for reactants / products, etc.

[0056] Unless explicitly described otherwise, the individual parts of the devices are interconnected in a manner customary and known in the field.

[0057] The various embodiments of the present invention, e.g. - but not exclusively - those of the various dependent claims, can be combined with each other in any way, provided that such combinations do not contradict each other.

[0058] It should be noted here that all described parts and functions are claimed as essential to the invention, both individually and in any combination, especially the details shown in the drawing. Modifications to this are familiar to those skilled in the art.

[0059] Furthermore, it is noted that the broadest possible scope of protection is sought. Therefore, the disclosure contained in the claims can also be specified by features that are described by further features (even if these further features are not necessarily included). It is explicitly pointed out that parentheses and the term "in particular" are intended to emphasize the optionality of features in the respective context (which does not imply that a feature is to be considered mandatory in the corresponding context without such indication).

[0060] Examples:

[0061] The invention will now be further explained with reference to the following non-limiting examples. In the experiments, several reactors according to the invention were arranged one above the other to form a multiple reactor arrangement according to the invention.

[0062] Example:

[0063] A reactor with two reactor subunits was operated, and the cooling water was recirculated. The first reactor subunit was already significantly deactivated due to its operating hours and sulfur contamination of the feed gas. The second reactor subunit was freshly filled with catalyst and had only been operated for a few hours. Due to the deactivation of the first reactor subunit, it was operated at 215°C. The pressure at its first pressure regulating device in the gas outlet from its first phase separation device was 18.2 bar. g and the CO conversion was 58%. The second reactor subunit was operated at 202°C, for which the pressure at its first pressure regulating device in the gas discharge from its first phase separation device was set to 14.1 bar. gThe CO conversion in the second reactor subunit was 71%. Complete recuperation at the first heat exchangers allowed the reactor inlet temperature of the recirculated coolant to be set to 210°C (for the first reactor subunit) and 197°C (for the second reactor subunit). 340 kg / h of water was fed into the first and second reactor subunits, respectively. The energy generated by condensing the produced vapor phase was completely transferred in a second, shared heat exchanger to generate steam for a RWGS process at 9 bar. g The condensed water mass flow, combined with liquid water from the first phase separation devices, was cooled to 133°C in a third heat exchanger using 25°C cooling water and then pumped back up to a pressure of 20 bar. g provided. The cooling water heated up to 43°C. Fiquren description:

[0064] The present invention is explained in more detail below with reference to the drawing. The drawing is not to be interpreted as limiting and is not to scale. It is schematic and does not include all features found in conventional devices, but is reduced to those essential for understanding the present invention. For example, screws, connections, etc., are not shown or not shown in detail. The drawing represents a preferred embodiment; however, not all possible embodiments or modifications according to the invention are illustrated in this drawing.

[0065] The same reference symbols indicate the same features in the figure, description, and claims.

[0066] Figure 1 illustrates the present invention in a highly schematic manner.

[0067] The figure above shows a reactor Rx with a certain number of reactor subunits (each consisting of a cooling layer and a reaction layer), represented by the variable "x". For the sake of simplicity, in the following, when referring to a specific reactor subunit x, it will not be explicitly named as such each time, but rather the corresponding device component will simply be represented by adding an "x"; for example, Wlx for the heat exchanger associated with the xth reactor subunit.

[0068] A feed gas stream F, comprising reaction gas, is fed into this reactor, and a product gas stream P exits the reactor after the reaction gas has been converted. These conversions include, for example, well-known exothermic reactions, i.e., reactions that require cooling of the reaction layers (or where cooling is at least advantageous).

[0069] A heated coolant stream Kla-x is discharged from the reactor. This coolant stream Kla-x is subjected to heat transfer (recuperation) via a first heat exchanger Wlx against the coolant partial stream Kx (as described below), whereby the coolant partial stream Kx is heated, and then introduced into the first phase separation device Blx.

[0070] In this first phase separation device Blx, the still relatively hot coolant is split into a gas phase stream (vapor phase) K2a-x and a liquid phase stream K2b-x. A first control device D-Rl-x is located in the line for the gas phase stream K2a-x leading out of the respective first phase separation device Blx. This device regulates the pressure to the desired boiling pressure for the respective cooling water supply Kle-x (see also the description above).

[0071] The gas phase streams K2a-x originating from the first phase separation devices Blx are guided downstream of the first control device D-Rl-x into a device VZ-G for combining the gas phase streams K2a-x into a single gas phase stream. Only this combined gas phase stream K2a is then derived from this device VZ-G.

[0072] Downstream of the device for combining the gas phase streams VZ-G, a second heat exchanger W-2 is arranged, configured to extract heat from the combined gas phase stream K2a and supply it to other applications. This is illustrated in the figure as follows: a stream of a heat-receiving substance WE-E (this substance is not referred to here as a coolant for clarity; it is usually water) enters the heat exchanger W-2 and receives heat from the combined gas phase stream K2a; the now heated heat-receiving substance WE-A then exits the heat exchanger W-2, and the heat can be used for other purposes, for example, to operate a reverse water-gas shift reaction or for supply to other applications.For the sake of simplicity, the combined gas phase stream K2a exiting the heat exchanger is still referred to here as a gas phase stream, although it is usually at least partially condensed; this is readily understandable to the expert and therefore does not need to be described in detail.

[0073] In each line carrying the liquid phase current K2b-x leading out of the first phase separation device Blx, there is a second control device D-R2-X. This device regulates the (liquid) level in the first phase separation device Blx.

[0074] Downstream of the second control device D-R2-X for controlling the level in the first phase separation device Blx, a device VZ-F is located for combining the liquid phase streams K2b-x corresponding to the number of reactor subunits, from which a combined liquid phase stream K2b is then derived. Furthermore, downstream of the second heat exchanger W-2 and the device VZ-F for combining the liquid phase streams K2b-x, a device VZ-T for combining the two gas and liquid phase streams K2a, K2b and combining them into a combined coolant stream K3 is arranged.

[0075] The combined coolant flow K3 can then, optionally but as shown in the figure, be directed via a third heat exchanger W-3 to pre-cool the combined coolant flow K3 against another heat-receiving substance.

[0076] As with the second heat exchanger shown above, the figure illustrates that a stream of heat-receiving substance WE-E (this substance is not referred to as coolant here for clarity; it is usually water) enters the heat exchanger W-3 and receives heat from the combined coolant stream K3; subsequently, the now heated heat-receiving substance WE-A exits the heat exchanger W-3, and the heat content can be used for other purposes.

[0077] Downstream of the merging device VZ-T or the heat exchanger W-3, if present, a second phase separation device or (pressurized) buffer tank B-2 can be arranged, through which the combined coolant flow K3 can be further treated, if necessary; in particular to avoid vaporous components in the supply line to the downstream return device (pump) Pl. In this buffer tank B-2, the mixed flow can additionally be cooled down to the maximum inlet temperature specified by the downstream return device (pump) Pl by means of controlled coolant flow (i.e., below the temperature at which no cavity problems occur or which the installed components can withstand).

[0078] Downstream of the merging device VZ-T or the optional heat exchanger W-3, or the second phase separation device B-2, if present, a return device Pl is arranged which is configured to return the merged coolant flow K3 as a return coolant flow KR to the reactor.

[0079] The return coolant flow KR from the recirculation device Pl is then directed to a device VA for dividing the return coolant flow KR into coolant partial flows Kx corresponding to the number of reactor subunits. From this point on, the devices again divide the coolant flow according to reactor subunits.

[0080] The coolant partial flows Kx generated in the device VA for splitting the return coolant flow KR are then fed via the first heat exchanger Wlx into the coolant inlet Kle-x of the respective reactor subunit. For this purpose, the coolant is heated to supply temperature in the first heat exchanger Wlx.

[0081] Furthermore, optionally, and as shown in the figure, a third control device BP-Rx (for controlling the bypass flow at Wlx) assigned to each reactor subunit Rx can be provided between the device VA for splitting the return coolant flow KR and the respective first heat exchanger Wlx. If this device is present, it is preferably configured to direct the coolant partial flows Kx via a respective bypass line BP-x, bypassing the respective first heat exchanger Wlx, directly into the respective coolant inlet Kle-x, in the event that the temperature of the coolant flow KR is too close to the boiling point of the coolant.

[0082] It should be clarified that the dashed line illustrates which respective assemblies / devices are present multiple times, i.e., in a number corresponding to the number of reactor subunits used. (In variants of the present invention, it is also possible to use a microreactor with a certain number of reactor subunits, of which only a portion is used (for example, for capacity reasons) - then the number of other devices to be used results from the number of reactor subunits actually used, not from the number of the maximum usable reactor subunits.)The devices not enclosed by the dashed line are used only once within the scope of the present invention (in variants of the present invention, one, several, or all of these devices may also be implemented multiple times; for example, to double the capacity – however, the actual number of devices not enclosed by the dashed line does not depend on the number of reactor subunits used). Corresponding to the hybrid status (change from multiple assignment to general or vice versa) of the device for combining gas-phase flows VZ-G and the device for combining liquid-phase flows VZ-F, as well as the device for dividing the return coolant flow KR into coolant partial flows Kx, the dashed line passes through these devices to illustrate this hybrid status.Although not shown in the drawing, it should be noted that in some embodiments of the present invention at least one flow indicator / flow control device and at least one pressure indicator / pressure control device may be arranged upstream of the third control device BP-Rx.

[0083] List of reference symbols:

[0084] WE-A escaping heat-receiving substance

[0085] WE-E incoming heat-receiving substance

[0086] F Feed (reaction gas)

[0087] Product (reaction gas)

[0088] Hlx assigned to the xth reactor subunit (optional) electrical

[0089] heater

[0090] Wlx, first heat exchanger assigned to the xth reactor subunit

[0091] W-2 second heat exchanger

[0092] W-3 third heat exchanger

[0093] Coolant inlet / coolant flow leading to the xth reactor subunit (Kle-x)

[0094] Kla-x coolant flow discharged from the xth reactor subunit (from the reactor subunit)

[0095] K2a-x gas phase stream assigned to the xth reactor sub-unit

[0096] (vapor phase current)

[0097] K2a Gas phase current (vapor phase current) (from x gas phase currents)

[0098] (vapor phase streams) combined)

[0099] K2b-x liquid phase stream assigned to the xth reactor subunit

[0100] K2b Liquid phase current (combined from x liquid phase currents)

[0101] K3 combined coolant flow

[0102] KR return coolant flow

[0103] VZ-G device for combining x gas phase flows

[0104] VZ-F device for combining x liquid phase flows

[0105] VZ-T Device for combining gas phase and

[0106] liquid phase current

[0107] D-Rl-x first control device assigned to the xth reactor subunit (for

[0108] Pressure regulation to the desired boiling pressure)

[0109] D-R2-X second control device assigned to the xth reactor subunit (for level control)

[0110] BP-Rx third control device assigned to the xth reactor subunit for

[0111] Control of the bypass current at WLX

[0112] Pl Return device Blx of the xth reactor subunit assigned first phase separation device

[0113] B-2 (optional) second phase separation device or (pressurized)

[0114] Buffer tank Rx xth reactor sub-unit

[0115] BP-x bypass line assigned to the xth reactor subunit

[0116] VA device for splitting the return coolant flow (KR) into x

[0117] Coolant partial flows (Kx), x consecutive number of the respective reactor subunit used

Claims

Claims:

1. Device for carrying out exothermic reactions, comprising at least one microreactor based on at least two stacked reactor subunits (Rx), wherein each reactor subunit (Rx) comprises at least one reaction layer and at least one cooling layer, and wherein each reactor subunit (Rx) is provided with its own coolant inlet (Kle-x) and its own coolant outlet (Kla-x), characterized in that each reactor subunit is assigned as separate components a first heat exchanger (Wlx), a first phase separation device (Blx) for splitting the coolant flow (Kla-x), a first control device (D-Rl-x) for pressure control to the desired boiling pressure for the cooling water supply (Kle-x), and a second control device (D-R2-x) for controlling the liquid level in the first phase separation device (Blx),wherein the first heat exchanger (Wlx) for the recovery of heat contained in the discharged coolant stream (Kla-x) is connected downstream of the coolant discharge of the respective reactor subunit; downstream of this heat exchanger (Wlx) is the first phase separation device (Blx) for splitting the coolant stream (Kla-x) into a gas phase stream (vapor phase stream) (K2a-x) and a liquid phase stream (K2b-x), wherein in the line leading out of the respective first phase separation device (Blx) for the gas phase stream (K2a-x) is the first control device (D-Rl-x) for pressure control to the desired boiling pressure for the respective cooling water supply (Kle-x), as well as in the respective line leading out of the respective first phase separation device, (Blx) the line for the liquid phase stream (K2b-x) is connected to the second control device (D-R2-x) for controlling the level in the first phase separation device (Blx); the lines for the gas phase streams (K2a-x) originating from the first phase separation devices (Blx) lead downstream of the first control device (D-Rl-x) to a device (VZ-G) for combining the gas phase streams (K2a-x) corresponding to the number of reactor subunits, from which a combined gas phase stream (K2a) is then derived; downstream of the device for combining the gas phase streams (VZ-G) a second heat exchanger (W-2) is connected, which is configured to extract heat from the combined gas phase stream (K2a) and to extract it for other applications;Downstream of the second control device (D-R2-x) for controlling the level in the first phase separation device (Blx), a device (VZ-F) for combining the liquid phase streams (K2b-x) corresponding to the number of reactor subunits is located, from which a combined liquid phase stream (K2b) is then derived; downstream of the second heat exchanger (W-2) and the device (VZ-F) for combining the liquid phase streams (K2b-x) corresponding to the number of reactor subunits, a device (VZ-T) for combining the two gas and liquid phase streams (K2a, K2b) and combining them into a combined coolant stream (K3) is located; downstream of the device for combining (VZ-T), a recirculation device (Pl) is located, configured to return the combined coolant stream (K3) as a return coolant stream (KR);downstream of the recirculation device (Pl) is a device (VA) for dividing the return coolant flow (KR) into coolant partial flows (Kx) corresponding to the number of reactor subunits; and; then the coolant partial flows (Kx) via the respective first heat exchanger (Wlx), whereby the coolant is heated to flow temperature in the respective first heat exchanger (Wlx), are led into the coolant inlet (Kle-x) of the respective reactor subunit; where x is the consecutive number of the respective reactor subunit (Rx) used.

2. Device according to claim 1, characterized in that a third heat exchanger (W-3) for pre-cooling the combined coolant flow (K3) against a second coolant is arranged as a further component in the course of the combined coolant flow (K3) between the device for combining (VZ-T) and the return device (Pl).

3. Device according to claim 1 or 2, characterized in that between the device (VA) for dividing the return coolant flow (KR) into coolant partial flows (Kx) corresponding to the number of reactor subunits and the respective first heat exchanger (Wlx) a third control device (BP-Rx) assigned to the respective reactor subunit (Rx) is provided, which is configured to direct the coolant partial flows (Kx) via a respective bypass line (BP-x) bypassing the respective first heat exchanger (Wlx) directly into the respective coolant inlet (Kle-x) in the event that the temperature of the coolant flow (KR) is too close to the boiling temperature of the coolant.

4. Device according to one of claims 1 to 3, characterized in that the second heat exchanger (W-2) is configured to transfer a portion of the heat contained in the gas phase stream (K2a-x) via indirect contact to a heat-receiving substance for the operation of a reverse water-gas shift reaction.

5. Device according to one of claims 1 to 4, in particular claim 1, characterized in that it is configured to use the heat extracted via the second heat exchanger (W-2) for other trades to generate steam.

6. Device according to one of claims 1 to 5, in particular claim 1, characterized in that a second phase separation device (B-2) is arranged upstream of the recirculation device (Pl), which is preferably configured to recool the combined coolant flow (K3) by quantity control with coolant to the maximum inlet temperature specified by the downstream recirculation device (Pl).

7. Device according to one of claims 1 to 6, in particular claim 1, characterized in that at least one flow indicator / flow control device and / or at least one pressure indicator / pressure control device is arranged upstream of the third control device (BP-Rx) in the direction of flow.

8. Method for boiling water cooling in devices for carrying out exothermic reactions, wherein the device comprises at least one microreactor based on at least two stacked reactor subunits (rx), each reactor subunit (Rx) comprising a reaction layer and a cooling layer, and wherein each reactor subunit (Rx) is provided with its own coolant inlet (Kle-x) and its own coolant outlet (Kla-x), characterized in that each reactor subunit comprises as separate components a first heat exchanger (Wlx), a first phase separation device (Blx) for dividing the coolant flow, a first control device (D-Rl-x) for pressure control to the desired boiling pressure for the cooling water supply (Kle-x), and a second control device (D-R2-x) for controlling the liquid level in the first phase separation device (Blx), and the method comprises steps i) to vi), wherein i) the coolant flow (Kla-x) discharged from the coolant outlet of the respective reactor subunit is subjected to heat recovery in the respective first heat exchanger (Wlx); ii) the coolant flow is then split in the respective first phase separation device (Blx) into a gas phase flow (vapor phase flow) (K2a-x) and a liquid phase flow (K2b-x), each of the two partial flows (K2a-x) and (K2b-x) discharged from the respective first phase separation device (Blx) being subjected to individual pressure control;iii) the gas phase streams (K2a-x) originating from the first phase separation device (Blx) are combined downstream of its pressure control via a device (VZ-G) for combining the gas phase streams corresponding to the number of reactor subunits into a combined gas phase stream (K2a); iv) downstream of this, heat is extracted from the combined gas phase stream (K2a) via a second heat exchanger (W-2) and extracted for other applications; v) the liquid phase streams (K2b-x) originating from the first phase separation device (Blx) are combined downstream of its pressure control via a device (VZ-F) for combining the x liquid phase streams into a combined liquid phase stream (K2b); vi) downstream of the second heat exchanger (W-2) and the device (VZ-F) for combining the liquid phase streams (K2b-x) corresponding to the number of reactor subunits; Liquid phase streams (K2a, K2b) are combined and merged into a coolant stream (K3); viii) the combined coolant stream (K3) is then returned as a return coolant stream (KR) by means of a recirculation device; ix) the return coolant stream (KR) is divided into coolant partial streams (Kx) corresponding to the number of reactor subunits via a device (VA) for dividing the return coolant stream (KR); x) the coolant partial streams (Kx) corresponding to the number of reactor subunits are then heated to supply temperature via the respective first heat exchanger (Wl-x) and returned to the coolant inlet (Kle-x) of the respective reactor subunit (Rx), where x is the consecutive number of the respective reactor subunit used.

9. Method according to claim 8, characterized in that step vii) involves pre-cooling the combined coolant flow (K3) in a third heat exchanger (W-3) against a second coolant between steps vi) and viii).

10. Method according to claim 8 or 9, characterized in that the second heat exchanger (W-2) transfers a portion of the heat contained in the gas phase stream (K2a) via indirect contact to a further coolant for the operation of a reverse water-gas shift reaction.

11. Use of the device according to any one of claims 1 to 7 for Fischer-Tropsch reactions or methanol synthesis.

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