Gas-liquid separator for an electrolysis system, electrolysis system

Abstract

The invention relates to a gas-liquid separator (1) for separating gases from a gas-liquid mixture for an electrolysis system, comprising a base body (2) with a circular cross-section, an inlet (3) for the gas-liquid mixture, a gas outlet (4), and a liquid outlet (5). According to the invention, the inlet (3) for the gas-liquid mixture is arranged tangentially with respect to the base body (2), and the base body (2) has a temperature control device (6).

Description

[0001] Die vorliegende Erfindung betrifft einen Gas-Flüssigkeitsseparator mit den Merkmalen des Oberbegriffs des Anspruchs 1. Darüber hinaus betrifft die Erfindung ein Elektrolysesystem mit einem erfindungsgemäßen Gas-Flüssigkeitsseparator.

[0002] A preferred application area of ​​the invention is electrolysis systems for the production of hydrogen. State of the art

[0003] In electrochemical cells, especially electrolysis cells, water reacts with electrical energy to form hydrogen and oxygen. This process releases waste heat, particularly during low-temperature electrolysis. The formation of hydrogen or oxygen in PEM electrolysis (PEM = "Protone Exchange Membrane") means that water molecules are consumed on the anode side or, due to the applied electric field, are converted into a hydrate shell of hydrogen. +Protons are transported to the cathode and react to form dissolved or gaseous hydrogen or oxygen. In practical applications, several of these cells are stacked. Within this cell stack, there are supply channels that provide the individual cells with water and electrical energy and remove the gases produced and the depleted solution.

[0004] During operation, water is typically supplied at a superstoichiometric level and simultaneously serves as a cooling and carrier fluid for the removal of residual heat and the generated gases in a so-called two-phase flow consisting of a gas and a liquid phase. The separation of the gas and liquid phases then takes place in a subsequent process step in a separator. For efficiency reasons, the gas phase is separated from the liquid phase first, before the depleted fluid is cooled in a heat exchanger. Currently, gas-liquid separation is achieved using horizontally arranged tanks as separators through passive degassing from the liquid medium within a specific residence time. The separation rate is a function of the temperature, pressure, viscosity, and residence time of the gas-liquid mixture.These separators typically have very large dimensions in order to separate larger quantities of fluid and gas and to ensure sufficient residence time within the separator.

[0005] Over time, during a continuous hydrogen production process, stack and / or cell components, such as the membrane of the electrolysis cells, can age, potentially leading to leaks. These leaks can cause hydrogen to pass into the oxygen path, or vice versa, rendering the separated gas mixture explosive. This poses a safety risk to the system. Of particular concern is the fact that, in such a case, not only the stack itself, but also all connected piping systems, tanks, and even the separator itself can become explosive.

[0006] The present invention aims to reduce the dimensions of a gas-liquid separator while simultaneously increasing its efficiency. Furthermore, it seeks to minimize the risk of explosion during the operation of a gas-liquid separator.

[0007] To solve this problem, a gas-liquid separator with the features of claim 1 is proposed. Advantageous embodiments of the invention are described in the dependent claims. Furthermore, an electrolysis system with a gas-liquid separator according to the invention is described. Disclosure of the invention

[0008] The proposed gas-liquid separator for an electrolysis system, used to separate gases from a gas-liquid mixture, has a circular base body with an inlet for the gas-liquid mixture, a gas outlet, and a liquid outlet. According to the invention, the inlet for the gas-liquid mixture is arranged tangentially to the base body, and the base body includes a temperature control device.

[0009] The proposed gas-liquid separator offers the advantage that the separation of the gas phase from the liquid phase is promoted by the tangentially arranged inlet, as this arrangement creates turbulence in the gas-liquid mixture flowing in through the inlet. Consequently, the gas-liquid separator can be designed to be smaller, thus saving space and costs. This, in turn, makes it possible to equip the main body of the gas-liquid separator with a temperature control device to simultaneously temper, and in particular cool, the incoming gas-liquid mixture. In this way, two process steps can be carried out simultaneously, further increasing the system's efficiency while simultaneously reducing the required installation space.

[0010] According to a preferred embodiment of the invention, the base body has a longitudinal axis that is oriented substantially vertically, with the gas outlet located at an upper end of the base body and the liquid outlet at a lower end, and with the inlet for the gas-liquid mixture being oriented tangentially to the base body in the region of the upper end. The substantially vertical orientation of the base body and the arrangement of the inlet in the region of the upper end of the base body optimize the flow conditions in the gas-liquid separator. Furthermore, gravity can be used to further assist the separation of the gas phase from the liquid phase. Both effects lead to a further increase in the efficiency of the gas-liquid separator.

[0011] Preferably, the base body has a conically shaped section. In the region of the conically shaped section, the flow is accelerated, thus further promoting the separation of the gas phase from the liquid phase.

[0012] Preferably, the conically shaped section tapers towards the lower end of the base body, forming a funnel-like structure through which the liquid phase is fed to the liquid outlet. The smaller cross-section at the lower end also facilitates easier discharge of the liquid for any subsequent process steps.

[0013] Preferably, the temperature control device is designed as a heat exchanger integrated into a cooling circuit. In this case, cooling is achieved using a cooling medium from the cooling circuit, which is passed through the heat exchanger. As it flows through the heat exchanger, the cooling medium absorbs heat from the gas-liquid mixture, which, preferably to optimize heat transfer, is separated from the heat exchanger only by the base body.

[0014] In its configuration as a heat exchanger, the temperature control unit also offers the possibility of volume-flow-controlled heat dissipation via the cooling medium. This volume-flow-controlled heat dissipation enables precise control of the system's cooling.

[0015] Furthermore, the temperature control device preferably comprises a coiled tube or cooling fins that can be supplied with a cooling medium. The coiled tube or cooling fins can be integrated into the base body or the wall of the base body, so that the cooling medium is separated from the gas-liquid mixture only by a wall. This further improves heat transfer.

[0016] As a further improvement measure, it is proposed that the gas-liquid separator be equipped with a gas sensor in the gas outlet area. This gas sensor, positioned at the outlet, enables analysis of the gas composition of the gas phase immediately after separation from the liquid phase. Any leaks or pinholes in the cell membranes, or excessively high hydrogen or oxygen content in the oxygen exhaust gas, can thus be detected at an early stage. This, in turn, allows for a faster response to leaks and / or pinholes, thereby increasing the operational safety of the system.

[0017] Advantageously, the gas flow rate is automatically measured using a commercially available gas sensor. Automating the gas analysis leads to faster and more accurate detection of explosive gas mixtures, further reducing the risk of explosion and—provided each stack has a separator—also enabling leak localization. In such cases, individual stacks can be selectively replaced without having to shut down the entire system.

[0018] Since the preferred application area of ​​a gas-liquid separator according to the invention is electrolysis systems, an electrolysis system with a gas-liquid separator according to the invention is also proposed. The efficient separation of the gas phase from the liquid phase achieved with the aid of the gas-liquid separator according to the invention also increases the efficiency of the electrolysis system. At the same time, installation space can be saved, since the gas-liquid separator can be made smaller. Further space savings result from the fact that the gas-liquid separator is equipped with a temperature control device, thus eliminating the need for a separate temperature control unit.

[0019] The invention and its advantages are described in more detail below with reference to the accompanying drawing or figure. This shows a schematic cross-section through a preferred embodiment of a gas-liquid separator according to the invention. Detailed description of the drawing

[0020] The figure shows an example of a gas-liquid separator 1 according to the invention for an electrolysis system. The gas-liquid separator 1 consists of a base body 2 with a circular cross-section and a longitudinal axis A that is vertically oriented. The base body 2 thus has an upper end 2.1 and a lower end 2.2. In the region of the upper end 2.1, the base body 2 has a tangential inlet 3 for a gas-liquid mixture and a gas outlet 4. In the region of the lower end 2.2, the base body 2 has a liquid outlet 5. A temperature control device 6 is also integrated into the base body 2.

[0021] The gas-liquid mixture flows into the base body 2 through inlet 3. Due to the tangential arrangement of inlet 3, the gas-liquid mixture is guided along an inner wall 7 of the base body 2, resulting in turbulence. This movement, caused by centrifugal force, separates the gas from the liquid in the vortex flow and simultaneously tempers, and in particular cools, the gas by the integrated temperature control unit 6. A cooling fluid flows through the temperature control unit 6 for this purpose.

[0022] The base body 2 of the gas-liquid separator 1 shown in the figure has a conically shaped section 8 that tapers towards the lower end 2.2. A gas sensor 9 mounted above the gas outlet 4 also measures the composition of the exiting gas phase and analyzes it for any potentially explosive components.

Claims

[1] Gas-liquid separator (1) for separating gases from a gas-liquid mixture for an electrolysis system, comprising a base body (2) with a circular cross-section, an inlet (3) for the gas-liquid mixture, a gas outlet (4) and a liquid outlet (5), characterized by , that the inlet (3) for the gas-liquid mixture is arranged tangentially with respect to the base body (2) and the base body (2) has a temperature control device (6). [2] Gas-liquid separator (1) according to claim 1, characterized by , that the base body (2) has a longitudinal axis (A) which is substantially vertically oriented, wherein the gas outlet (4) is located at an upper end (2.1) of the base body (2) and the liquid outlet (5) is located at a lower end (2.2) of the base body (2) and wherein the inlet (3) for the gas-liquid mixture is oriented tangentially to the base body (2) in the region of the upper end (2.1). [3] Gas-liquid separator (1) according to claim 1 or 2, characterized by , that the base body (2) has a conically shaped section (8) which preferably tapers towards the lower end (2.2). [4] Gas-liquid separator (1) according to any one of the preceding claims, characterized by , that the temperature control device (6) is designed as a heat exchanger which is integrated into a cooling circuit. [5] Gas-liquid separator (1) according to any one of the preceding claims, characterized by , that the temperature control device (6) has a coil of tubing or cooling fins which can be supplied with a cooling medium. [6] Gas-liquid separator (1) according to any one of the preceding claims, characterized by , that the gas-liquid separator (1) has a gas sensor (9) in the area of ​​the gas outlet (4). [7] Electrolysis system with a gas-liquid separator (1) according to one of the preceding claims.

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