Dihydrogen production facility and associated infrastructure

Abstract

The invention relates to a hydrogen production installation (4) comprising: a production line (12) for an outlet stream (16) of steam from an inlet stream (10) of liquid water; and an electrochemical device (14) configured to produce hydrogen from the outlet stream (16). The steam production line (12) comprises: an expansion stage (18) configured to: reduce the pressure of the inlet stream (10) to a first pressure value; and ensure heat exchange between the inlet stream (10) and a primary heat source (22), external to the installation (4), in order to vaporize the water in the inlet stream (10) and deliver an intermediate steam stream (23); a compression stage (20) configured to bring the intermediate steam stream to a second pressure value strictly higher than the first pressure value. Figure 1

Description

Title of the invention: Hydrogen production plant and associated infrastructure technical field

[0001] The present invention relates to a dihydrogen production installation comprising: • a steam production line configured to produce, from an inlet stream comprising liquid water, an outlet stream comprising water vapor; and • an electrochemical device connected to the outlet of the steam production line and configured to produce dihydrogen from the available output stream at the outlet of the steam production line.

[0002] The invention also relates to an infrastructure comprising such an installation.

[0003] The invention applies to the field of industrial production of dihydrogen, and in particular to installations implementing solid oxide electrolysis cells. State of the art

[0004] In the field of dihydrogen production, it is classically known to use electrolysis systems employing a proton exchange membrane (or PEM, from the English "Proton Exchange Membrane"), an anion exchange membrane (or AEM, from the English "Anion Exchange Membrane"), or even an alkaline technology.

[0005] More recently, so-called SOE (Solid Oxide Electrolysis) systems, offering better efficiency than conventional systems, have emerged. Such SOE systems are configured to produce dihydrogen from an inlet stream of water vapor.

[0006] In general, the efficiency of an electrolysis system is defined as the electrical energy consumed by the electrolysis system for one kilogram of dihydrogen produced.

[0007] More specifically, an SOE electrolysis system has an efficiency greater than 80%, which is about 30% better performance than that of PEM electrolysis systems.

[0008] Such an improvement in efficiency relies largely on the use of waste heat lost by an industrial installation, for example, at a corresponding exhaust outlet (chimney, exhaust duct, etc.). More precisely, the waste heat extracted from the equivalent installation is used, in the associated dihydrogen production facility, to vaporize an inlet stream of liquid water into a stream of water vapor intended to be hydrolyzed by the SOE electrolysis systems of said dihydrogen production facility.

[0009] However, conventional dihydrogen production installations with SOE electrolysis systems do not provide complete satisfaction.

[0010] Indeed, as previously stated, the hydrolysis reactions implemented by SOE electrolysis systems require the use of steam. Consequently, the analogous installations with which current dihydrogen production installations are likely to be associated are limited to those whose waste heat is available at a temperature greater than or equal to 100°C, or even greater than or equal to 150°C.

[0011] This results in a limitation on the similar installations to which a dihydrogen production installation with SOE electrolysis systems can be associated, and therefore on the development prospects of this sector.

[0012] One object of the present invention is to remedy at least one of the drawbacks of the prior art.

[0013] Another object of the invention is to propose a dihydrogen production installation that is compatible with a larger number of similar installations.

[0014] Another object of the invention is to propose a dihydrogen production installation that is compatible with installations whose waste heat is available at a temperature less than or equal to 150°C, or even less than or equal to 100°C. Description of the invention

[0015] To this end, the invention relates to a hydrogen production installation of the aforementioned type, in which the steam production line comprises: • a relaxation stage configured for: • lower the inlet flow pressure to a first pressure value; and • ensure heat exchange between the inlet flow and a primary heat source, external to the installation, in order to vaporize the water in the inlet flow and deliver an intermediate steam flow; • a compression stage configured to bring the intermediate vapor flow to a second pressure value strictly greater than the first pressure value, in order to produce the outlet flow.

[0016] Indeed, the temperature required for liquid water to change into vapor decreases with pressure. Therefore, thanks to the expansion stage, the use of It is possible to have available waste heat at a temperature of 150°C or lower, or even 100°C or lower.

[0017] It follows that a larger number of similar installations are likely to be used for joint operation with such a dihydrogen production installation.

[0018] Furthermore, the inventors discovered the surprising effect whereby the energy balance of such a transformation is very favorable, insofar as the input of latent heat of vaporization represents the largest part of the energy required during such a transformation. Now, thanks to the invention, the drop in pressure leads to a decrease in latent heat.

[0019] Advantageously, the dihydrogen production installation according to the invention has one or more of the following characteristics, taken individually or in any technically feasible combination:

[0020] The expansion stage comprises: • a pressure-reducing chamber configured to lower the inlet flow pressure to the first pressure value; and • a heat exchanger configured to ensure heat exchange between the inlet flow available at the outlet of the expansion chamber and the primary heat source;

[0021] the first pressure value is less than atmospheric pressure;

[0022] the second pressure value is greater than or equal to atmospheric pressure;

[0023] the compression stage is, moreover, configured to ensure heat exchange between the intermediate flow and a secondary heat source;

[0024] the secondary heat source is an electrical heat source;

[0025] the electrochemical device is a solid oxide electrolyzer.

[0026] According to another aspect of the invention, an infrastructure is proposed comprising a dihydrogen production installation as defined above and a second installation separate from the dihydrogen production installation, an exhaust outlet of the second installation being connected to the expansion stage to form the primary heat source. Brief description of the figures

[0027] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0028] [Fig.1] is a schematic representation of an infrastructure according to the invention.

[0029] It is understood that the embodiments described below are by no means limiting. Variants of the invention may, in particular, be imagined comprising only a selection of features described hereafter in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection includes at least one preferably functional feature without structural details, or with only a portion of the structural details if it is this portion that is solely sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0030] In particular, all the variants and all the embodiments described are combinable with each other if nothing prevents this combination from a technical point of view.

[0031] In the figures and in the rest of the description, elements common to several figures retain the same reference. Detailed description

[0032] An infrastructure 2 according to the invention is illustrated by [Fig.1].

[0033] Infrastructure 2 includes a dihydrogen production facility 4 (referred to as "production facility") and a second facility 6 (also referred to as "counterpart facility"), separate from production facility 4.

[0034] The corresponding installation 6 is, for example, an industrial installation, such as a steel production or processing plant, a cement production plant, a glass production plant, an incineration plant, a chemical or petrochemical production plant, a geothermal thermal recovery plant, etc.

[0035] As illustrated by the figure, the corresponding installation 6 includes an exhaust outlet 8, at which level waste heat is available.

[0036] Preferably, the temperature at the outlet of the evacuation 8 of the corresponding installation 6 is less than or equal to 150°C, for example between 50°C and 110°C.

[0037] In this figure, the black arrows represent flows including water in the liquid state, while the white arrows represent flows including water in the vapor phase.

[0038] The production facility 4 is configured to produce dihydrogen from an inlet stream 10 comprising liquid water.

[0039] The production installation 4 comprises a steam production line 12 and an electrochemical device 14 fluidly connected at the outlet of the steam production line 12.

[0040] More specifically, the steam production line 12 is configured to produce an outlet stream 16 comprising steam. Furthermore, the device electrochemical 14 is configured to produce dihydrogen from the outlet stream 16 received from the steam production line 12.

[0041] For the purposes of the present invention, the expression "A fluidically connected / linked / connected to B" means that "A is in fluidic connection with B", but does not exclude the presence of one or more organ(s) between A and B.

[0042] Steam production line 12

[0043] As shown in the figure, the steam production line 12 comprises an expansion stage 18 and a compression stage 20 fluidly connected at the outlet of the expansion stage 18.

[0044] Expansion stage 18

[0045] The expansion stage 18 is connected to the exhaust outlet 8 of the corresponding installation 6, so that the exhaust outlet 8 forms a primary heat source 22, external to the production installation 4.

[0046] The expansion stage 18 is configured to lower the pressure of the inlet flow 10 to a first pressure value.

[0047] In addition, the expansion stage 18 is configured to ensure heat exchange between the inlet flow 10 and the primary heat source 22 (in this case the exhaust outlet 8 of the corresponding installation 6), in order to vaporize the water from the inlet flow 10, and deliver an intermediate steam flow 23 comprising water vapor.

[0048] Preferably, the expansion stage 18 comprises an expansion chamber 24 and a heat exchanger 26 fluidly connected to each other.

[0049] More specifically, the expansion chamber 24 is configured to receive the inlet flow 10, and to lower the pressure of the inlet flow 10 to the first pressure value.

[0050] Advantageously, the first pressure value is lower than atmospheric pressure. This characteristic is advantageous because it helps to lower the temperature required to vaporize the inlet flow 10, since a decrease in water pressure results in a decrease in the temperature required for its boiling.

[0051] Preferably, the first pressure value is dependent on the temperature of the primary heat source 22 and is, for example, between 0.2 bar and 0.9 bar absolute.

[0052] For example, the expansion chamber 24 includes a tank 28 to which a pump 30 is fluidly connected. In this case, the pump 30 is configured to, in operation, reduce the pressure in the tank 28 by a displacement of matter from the inside of the tank 28 to the outside of the tank 28.

[0053] Furthermore, the heat exchanger 26 is configured to ensure heat exchange between the available flow at the outlet of the expansion chamber 24 (i.e. the flow inlet whose pressure is equal to the first pressure value) and the primary heat source 22, in order to produce the intermediate steam flow 23 from the inlet flow 10.

[0054] In particular, the heat exchanger 26 comprises: • a cold inlet EF, fluidly connected to the outlet of the expansion chamber 24 to receive the flow obtained after raising the pressure of the inlet flow 10 to the first pressure value; and • a hot outlet SC for delivering the intermediate steam flow 23.

[0055] In addition, the heat exchanger 26 includes a heat collection portion 32 for extracting, from the primary heat source 22, the heat required for vaporizing the flow circulating from the cold inlet EC to the hot outlet EF. In particular, the heat collection portion 32 is a fluidly connected conduit to the exhaust outlet 8 of the corresponding installation 6.

[0056] Alternatively, the expansion stage 18 is configured so that heat exchange takes place directly with the tank 28, by means of an evaporator.

[0057] Compression stage 20

[0058] The compression stage 20 is configured to bring the intermediate vapor flow 23 to a second pressure value strictly greater than the first pressure value, in order to produce the outlet flow 16.

[0059] Preferably, the second pressure value is greater than or equal to atmospheric pressure

[0060] Advantageously, the compression stage 20 is further configured to ensure heat exchange between the intermediate steam stream 23 and a secondary heat source (not shown). This feature is advantageous because, depending on the temperature of the steam in the intermediate steam stream 23, the pressure increase of said intermediate steam stream 23 at the compression stage 20 is likely to place said steam in a thermodynamic state favorable to its condensation. The secondary heat source thus makes it possible to maintain the steam in a state of saturation or even superheating, thereby eliminating the risk of condensation.

[0061] For example, the secondary heat source is an electrical heat source, or any other type of heat source.

[0062] Electrochemical device 14

[0063] The electrochemical device 14 is connected to the outlet of the steam production line 12 to receive the outlet flow 16. In particular, an inlet 14E of the electrochemical device 14 is fluidly connected to an outlet of the compression stage 20.

[0064] In addition, the electrochemical device 14 is configured to produce dihydrogen from the output stream 16 available at the outlet of the steam production line 12.

[0065] For example, the electrochemical device 14 is an electrolyzer, preferably a solid oxide electrolyzer.

[0066] In particular, the electrochemical device 14 is configured to produce at least one resulting flux 36 from the output flux 16.

[0067] In particular, the at least one resulting flow 36 comprises a first resulting flow 38 comprising dihydrogen, evacuated through a first evacuation conduit 40.

[0068] Preferably, the at least one resulting flow 36 also includes a second resulting flow 42 comprising dioxygen, discharged through a second discharge pipe 44.

[0069] Operation

[0070] The operation of infrastructure 2 will now be described.

[0071] During its operation, the approved installation 6 produces waste heat, available at its exhaust outlet 8, forming the primary heat source 22.

[0072] In addition, the production installation 4 receives the inlet flow 10 comprising liquid water.

[0073] Within the expansion stage 18 of the steam production line 12 of the production installation 4, and more specifically in the expansion chamber 24, the pressure of the inlet flow 10 is lowered to the first pressure value.

[0074] Then, a heat exchange is carried out at the level of the heat exchanger 26, between, on the one hand, the available flow at the outlet of the expansion chamber 24 and, on the other hand, the primary heat source 22, in order to produce the intermediate steam flow 23.

[0075] Then, the intermediate steam flow 23 is routed to the compression stage 20.

[0076] Then, within the compression stage 20, the pressure of the intermediate flow of steam 23 is brought to the second pressure value, strictly greater than the first pressure value, in order to produce the outlet flow 16 comprising water vapor.

[0077] Then, the output stream 16 is routed to the input 14E of the electrochemical device 14.

[0078] The electrochemical device 14 then produces dihydrogen from the output stream 16 received from the steam production line 12.

[0079] More specifically, the electrochemical device 14 produces at least one resultant flux 36 from the output flux 16. In particular, the at least one resultant flux 36 comprises a first resultant flux 38 comprising dihydrogen, discharged through a first discharge conduit 40.

[0080] Of course, the invention is not limited to the examples just described.

Claims

Demands

1. Installation (4) for the production of dihydrogen comprising: • a steam production line (12) configured to produce, from an inlet stream (10) comprising liquid water, an outlet stream (16) comprising water vapor; and • an electrochemical device (14) connected at the outlet of the steam production line (12) and configured to produce dihydrogen from the outlet stream (16) available at the outlet of the steam production line (12), The hydrogen production installation (4) is characterized in that the steam production line (12) comprises: • a relaxation stage (18) configured for: • lower the inlet flow pressure (10) to a first pressure value; and • ensure heat exchange between the inlet stream (10) and a primary heat source (22), external to the installation (4), in order to vaporize the water from the inlet stream (10) and deliver an intermediate steam stream (23); • a compression stage (20) configured to bring the intermediate steam flow (23) to a second pressure value strictly greater than the first pressure value, in order to produce the outlet flow (16).

2. Installation (4) according to claim 1, wherein the expansion stage (18) comprises: • a pressure-reducing chamber (24) configured to lower the inlet flow pressure to the first pressure value; and • a heat exchanger (26) configured to ensure heat exchange between the inlet flow available at the outlet of the expansion chamber and the primary heat source.

3. Installation (4) according to claim 1 or 2, wherein the first pressure value is less than atmospheric pressure.

4. Installation (4) according to any one of claims 1 to 3, wherein the second pressure value is greater than or equal to atmospheric pressure.

5. Installation (4) according to any one of claims 1 to 4, wherein the compression stage (20) is further configured to provide heat exchange between the intermediate flow (23) and a secondary heat source.

6. Installation (4) according to claim 5, wherein the secondary heat source is an electric heat source.

7. Installation (4) according to any one of claims 1 to 6, wherein the electrochemical device (14) is a solid oxide electrolyzer.

8. Infrastructure (2) comprising a hydrogen production facility (4) according to any one of claims 1 to 7 and a second facility (6) separate from the hydrogen production facility (4), an exhaust outlet (8) of the second facility (6) being connected to the expansion stage (18) to form the primary heat source (22).

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