A hydrogen leakage recovery system

Abstract

The present disclosure relates to a hydrogen leakage recovery system (1), the system (1) comprising: at least one turbomachinery unit (11); and a recovery unit (12) fluidically coupled with said at least one turbomachinery unit (11), the recovery unit (12) comprising: a separator (121) configured to receive a mixture of hydrogen and other compounds leaked from the turbomachinery unit (11), and to separate the hydrogen from the other compounds so as to obtain a hydrogen stream, and a compressor (123) fluidically coupled with the separator (121), the compressor (123) being configured to receive the hydrogen stream from the separator (121) and to compress the hydrogen stream so as to obtain a compressed hydrogen stream.

Description

A hydrogen leakage recovery systemDescriptionTECHNICAL FIELD

[0001] The present disclosure concerns a hydrogen leakage recovery system that allows to recover hydrogen from a mixture of hydrogen and other compounds leaked from the turbomachinery unit.

[0002] The present disclosure also concerns a method of operating the hydrogen leakage recovery system.BACKGROUND ART

[0003] Turbomachinery units such as compressors, turbo expander, gas turbines and the like are utilised in various industrial applications, particularly in the processing and transportation of gases and fluids, such as hydrogen. These machines operate under conditions of high pressure and temperature, which necessitates the implementation of robust sealing systems to ensure operational integrity and safety. The primary function of these sealing systems is to prevent the unintended escape of process gas (i.e. hydrogen), which can occur through the small gaps or clearances between stationary and rotating parts of the machinery, such as between the rotating parts of a compressor, a turbo expander or a gas turbine. Such gaps are inevitable due to the need for relative motion between the parts. The pressure differential between the internal process environment and the ambient surroundings further contributes the potential for leakage.

[0004] To mitigate this risk, sealing systems are typically buffered, meaning they are supplied with an auxiliary sealing gas — commonly nitrogen, although other inert or reactive gases may be used depending on the specific application. This sealing gas (also known as “buffer gas”) is injected into the sealing system at a pressure slightly higher than that of hydrogen. The intentional overpressure ensures that any mixed gas leakage consists predominantly of the sealing gas rather than the process gas.

[0005] The sealing system is engineered to allow a controlled leakage rate. This leakage, comprising a mixture of process gas and sealing gas, is carefully managed. It is routed through a designated pathway to a collection or disposal system. In most cases, this involves directing the leakage to a vent or flare system. Venting is employedwhen the leaked gas can be safely released into the atmosphere after ensuring that it meets environmental regulations, whereas flaring involves combusting the mixed gas containing hydrogen to convert it into less harmful emissions.

[0006] However, recent studies have classified hydrogen as an indirect greenhouse gas (GHG) with a significant impact on climate and atmospheric composition. The Global Warming Potential (GWP) key indicator is used to quantify the effect of hydrogen on the atmosphere. Greenhouse gases can absorb the wavelengths of thermal radiation emitted by the Earth. This effect accounts for the greater part of the hydrogen depletion (65 - 85%).

[0007] In light of the above, there is a need for reducing emission within the atmosphere of hydrogen leaked from a turbomachinery unit.SUMMARY

[0008] Certain aspects commensurate in scope with the originally claimed disclosure are summarized below. These aspects are not intended to limit the scope of the claimed disclosure, but rather these aspects are intended only to provide a brief summary of possible forms of the disclosure. Indeed, the full disclosure may encompass a variety of forms that may be similar to or different from the aspects set forth below.

[0009] In one aspect, the subject matter disclosed herein is directed to a hydrogen leakage recovery system comprising: at least one turbomachinery unit; and a recovery unit fluidically coupled with said at least one turbomachinery unit, the recovery unit comprising: a separator configured to receive a mixture of hydrogen and other compounds leaked from the turbomachinery unit, and to separate the hydrogen from the other compounds so as to obtain a hydrogen stream; and a compressor fluidically coupled with the separator, the compressor being configured to receive the hydrogen stream from the separator and to compress the hydrogen stream so as to obtain a compressed hydrogen stream.

[0010] In another aspect, the subject matter disclosed herein is directed to a method of operating a hydrogen leakage recovery system as defined above, the method comprising: receiving at recovery system a mixture of hydrogen and other compounds from the turbomachinery unit; separating using the separator the hydrogen from the other compounds so as to obtain a hydrogen stream; receiving the hydrogen stream at the compressor fluidically coupled with the separator; and compressing the hydrogenstream using said compressor.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:Fig. 1 illustrates a schematic view of a hydrogen leakage recovery system, according to an embodiment of the present disclosure;Fig. 2 illustrates block diagram of a method of operating a hydrogen leakage recovery system shown in Fig. 1.DETAILED DESCRIPTION OF EMBODIMENTS

[0012] Sealing systems for turbomachinery unit are conventionally engineered to allow a controlled leakage rate of a gas mixture comprising a mixture of process gas (e.g. hydrogen) and other compounds. However, the mixture is conventionally routed through a designated pathway to a disposal system which involves directing the leakage to a vent or flare.

[0013] In order to reduce emission within the atmosphere of hydrogen leaked from a turbomachinery unit, a hydrogen leakage recovery system can be employed to capture leaked mixtures comprising hydrogen for re-usage in the system or to be used elsewhere, such as for user distribution.

[0014] Fig. 1 illustrates a schematic view of a hydrogen leakage recovery system 1, according to an embodiment of the present disclosure. The hydrogen leakage recovery system 1 can be applied to recover hydrogen when hydrogen is used as process gas, as well as in any other application which processes a hydrogen carrier containing other compounds (e.g. syngases, which are mixture of gases primarily composed of hydrogen). The hydrogen leakage recovery system 1 can be utilized in LNG (Liquefied Natural Gas) operations, pipeline gas processing, refineries, petrochemical industries, and various other industrial applications. For example, the hydrogen leakage recovery system 1 may be part of a liquefaction system. However, it is evident that the present invention should not be limited to the specific uses herein described, in fact the hydrogen leakage recovery system 1 can be used also in green hydrogen plant or greenammonia plant whereby, respectively, hydrogen is produced by splitting water into hydrogen and oxygen using renewable energy sources like solar, wind, or hydroelectric power, whereas green ammonia is produced using green hydrogen and renewable energy.

[0015] The hydrogen leakage recovery system 1 comprises: at least one turbomachinery unit 11 and a recovery unit 12 fluidically coupled with the at least one turbomachinery unit 11.

[0016] The at least one turbomachinery unit 11 may comprise for example a compressor system for compressing hydrogen. Examples of the compressor system can include single-casing compressors, multi-stage compressors, and trains of multiple compressors, each with one or more compression stages. The compressor system can be driven by a mover, which can be, e.g., a gas turbine, a steam turbine, an expander, or an electric motor that receives electric power from an external power source. In another example the turbomachinery unit 11 may comprise a gas turbine, or a turbo expander. In Fig. 1 the turbomachinery unit 11 comprises a first turbomachinery unit 11-1 and a second turbomachinery unit 11-2, which may be of the same or different type.

[0017] As shown in Fig. 1, the turbomachinery unit 11 may be fed by one or more supply lines for supplying the at least one turbomachinery unit 11 with a source of hydrogen. In particular, the first box 21 represents a source of “green hydrogen”, which is hydrogen produced through electrolysis powered by renewable energy. The first box 21 is fluidically coupled to the turbomachinery unit 11 for supplying green hydrogen to the turbomachinery unit 11. The second box 22 in Fig. 1 represents a source of “blue hydrogen”, which is hydrogen derived from natural gas using carbon capture technology. The second box 22 is fluidically coupled to the turbomachinery unit 11 for supplying blue hydrogen to the turbomachinery unit 11. The third box 23 represents other clean hydrogen, which is hydrogen obtained via pyrolysis or similar processes. The third box 23 is fluidically coupled to the turbomachinery unit 11 for supplying clean hydrogen to the turbomachinery unit 11. The fourth box 24 represents a source of “clean hydrogen carriers”, which is liquid organic hydrogen carriers containing other compounds, such as ammonia. The fourth box 24 is fluidically coupled to the turbomachinery unit 11 for supplying the hydrogen carrier to the turbomachinery unit 11.

[0018] During normal operation of the hydrogen leakage recovery system 1, the turbomachinery unit 11 outputs a stream of hydrogen free of other compounds that is directed to the first exit point 13 for user distribution using the output line 111. However, the turbomachinery unit 11 may leak hydrogen due to imperfect sealing at various locations where the sealing elements of the turbomachinery unit 11 are located. The sealing elements can be, e.g., labyrinth seals, or other seal assemblies. The seal element / assembly avoids process gas (i.e. hydrogen) flowing outside the turbomachinery unit 11 through gaps between moving parts thereof, due to the pressure difference with the surrounding environment. However, in order to prevent hydrogen from leaking through the sealing elements due to imperfect sealing, a sealing gas can be delivered into a region adjacent to the respective seal assembly, thus preventing hydrogen from leaking through the sealing assembly / element. The seal assembly is thus configured to receive a sealing gas stream for containment of hydrogen within the turbomachinery unit 11. The sealing gas can be injected into the sealing system at a pressure higher than that of hydrogen to ensure that any mixed gas leakage consists predominantly of the sealing gas rather than the process gas. By introducing the sealing gas a controlled leakage is created containing process gas (i.e. hydrogen) plus sealing gas (e.g. nitrogen). Thus, the portion of sealing gas that leaks through the seal assembly can combine with hydrogen to create a mixture of hydrogen and other compounds at a respective vent the turbomachinery unit 11. For example, the turbomachinery unit 11 may comprise one or more vent for collecting the mixture leaked from the at least one turbomachinery unit 11, and one or more exhaust lines 114-1, 114-2 fluidically coupled to the one or more vent and the recovering unit 12 to direct the leaked flow of the respective turbomachinery units 11-1, 11-2 to the recovery unit 12.

[0019] The recovery unit 12 comprises in turn a separator 121 configured to receive a mixture of hydrogen and other compounds leaked from the turbomachinery unit 11, and to separate the hydrogen from the other compounds so as to obtain a hydrogen stream. The separator 121 can be for example, a two-phase separator that is configured to separate an input fluid into two or more different phases, such as into the liquid and gaseous fractions. In another example, the separator 121 can be a membrane able to produce a continuous flow of hydrogen free of other compounds by filtration. In a further example, the separator 121 may be a demister type separator, which comprisesa mesh or pad made of fine wires or filaments configured to remove liquid droplets from a gas stream thus allowing to separate condensates from the gas stream. However, it is evident that the present invention should not be limited to the specific types of separators herein described, in fact, in another example, the separator 121 may also be a dehydrator unit separator, or more generically a unit configured to separate the hydrogen from the other compounds.

[0020] The other compounds may comprise at least one of the following: oxygen, methane, nitrogen, and water. In a further example, the separator 121 can be able to separate various components of the other compounds such as, to obtain a separate stream of oxygen, nitrogen and water that can be used in a variety of ways or stored separately within the system 1.

[0021] The recovery unit 12 further comprises a compressor 123 fluidically coupled with the separator 121. The compressor 123 is configured to receive the hydrogen stream from the separator 121 and to compress the hydrogen stream so as to obtain a compressed hydrogen stream.

[0022] The compressed hydrogen stream can be handled in a variety of ways. For example, the compressor 123 may be configured to deliver at least a portion of the compressed hydrogen stream to at least one of: (i) the at least one turbomachinery unit 11, (ii) a first exit point 13 of the leakage recovery system 1 for user distribution, and (iii) an external component 30 fluidically coupled with the hydrogen leakage recovery system 1.

[0023] The external component 30 may comprise, for example, at least one of: a gas turbine, an external fuel cell, and a refuelling station. In one example, the compressed hydrogen stream outputted by the compressor 123, or a portion of it, can be returned back at the inlet of the turbomachinery unit 11 to be further compressed and condensed by the turbomachinery unit 11. The hydrogen stream is thus re-injected into the turbomachinery inlet without polluting the main inlet flow with nitrogen or other compounds. In another example, the hydrogen stream, or a portion of it, can be stored in a storage vessel of a refuelling station. In a further example, at least a portion of the hydrogen stream can be delivered to the exit point 13 of the system 1 for use elsewhere, such as for user distribution.

[0024] The recovery unit 12 may be fluidically coupled with at least one output linecomprising: a return line 116 for directing the at least a portion of the compressed hydrogen stream to the at least one turbomachinery unit 11, a distribution line 117 for directing the at least a portion of the compressed hydrogen stream to the first exit point 13 of the leakage recovery system 1, and a usage line 118 for directing the at least a portion of the compressed hydrogen stream to the external component 30.

[0025] The output line may comprise at least one controlling valve 16, 17, 18 for controlling the distribution of compressed hydrogen to the respective output lines 116, 117, 118. For example, as shown in Fig. 1, the return line 116 comprises a first control valve 16 that allows to regulate the flow and / or pressure of the gas within the return line 116; the distribution line 117 comprises a second control valve 17 that allows to regulate the flow and / or pressure of the gas within the distribution line 117; and the usage line 118 comprises a third control valve 18 that allows to regulate the flow and / or pressure of the gas within the usage line 118.

[0026] The recovery unit 12 may further comprise a purifier 122 for removing impurities from the hydrogen stream. As shown in Fig. 1 the purifier 122 is fluidically coupled to the compressor 123 for providing a purified stream of hydrogen to the compressor 123. The gas purifier 122 is configured to perform a purification process which involves filtering out other gases to meet specific quality requirements. The purifier 122 may be, for example, a membrane type purifier; a catalytic type purifier; or a multi-stage absorber designed to sequentially separate the stream of hydrogen into a purified stream of hydrogen, liquid hydrocarbons (oil or condensate), and water. For example, the purifier 122 can comprise a multi-stage gas separator, whereby the gas stream undergoes sequential separation to remove different phases by combining multiple purification technique like coalescing filtration, adsorption, catalytic reaction, condensation, dehydration, acid gas removal, demethanization, nitrogen extraction or the like.

[0027] The separator 121, the purifier 122, and the compressor 123 of the recovery unit 12 can either be part of a same device or be separate, independent sub-units of the recovery unit 12, which are fluidically connected as shown in Fig. 1. The sub units 121, 122 and 123 could be installed in any order, and thus not necessarily in the sequential order depicted in Fig. 1. For example, in a variant the compressor 123 could be placed before the purifier 122 or after it, depending on the specific application.

[0028] The recovery unit 12 may be configured to obtain / generate a stream of othercompounds. Accordingly, the separator 121 may be configured to receive a mixture of hydrogen and other compounds leaked from the turbomachinery unit 11, and to separate the hydrogen from the other compounds so as to obtain / generate a hydrogen stream and a stream of other compounds. Using the output line 115 that is fluidically coupled to the recovery unit 12, the stream of other compounds can be directed to a second exit point 14 of the hydrogen leakage recovery system 1 for user distribution.

[0029] With reference to Fig. 2 there is shown a block diagram of a method 100 of operating a hydrogen leakage recovery system 1 shown in Fig. 1.

[0030] At step 101 of the method 100 the recovery system 12 receives a mixture of hydrogen and other compounds from the turbomachinery unit 11.

[0031] At step 102 of the method 100 the separator 121 separates the hydrogen from the other compounds so as to obtain a hydrogen stream.

[0032] The method 100 may further comprise step 103 in which the hydrogen stream is purified with the purifier 122, fluidically coupled to the compressor 123.

[0033] At step 104 of the method 100 the compressor 123 receives the hydrogen stream.

[0034] At step 105 of the method 100 the hydrogen stream is compressed by the compressor 123.

[0035] The method 100 may further comprise step 106 whereby at least a portion of the separated hydrogen stream is delivered to at least one of (i) the at least one turbomachinery unit 11, (ii) a first exit point 13 of the leakage recovery system 1, and (iii) an external unit 30 fluidically coupled with the hydrogen leakage recovery system 1.

[0036] Exemplary technical effects of the method and system, described herein include, by way of non-limiting example, the ability to recover, and separate, and store hydrogen and / or the other components that leak from turbomachinery unit; and the ability to minimize / avoid waste of process gases.

[0037] For example, a first advantage of the present disclosure is to provide a hydrogen leakage recovery system 1 that operates without emitting any carbon dioxide (CO2) or other greenhouse gases (e.g. hydrogen) into the atmosphere. The system 1 could be applied to multiple turbomachinery units 11.

[0038] A second advantage of the present disclosure, is that the system 1 allows to recover hydrogen leakages from turbomachinery units 11 (such as compressor systems) through a recovery unit 12 that splits hydrogen flow from the other compounds present in the leaked mixture. The hydrogen stream outputted from the recovery unit 12 can then be redirected to compressor suction (i.e. the inlet of the turbomachinery units 11) or can be directed elsewhere for different uses (i.e. fuel cell, gas turbine, etc). In this way it is avoided to have leakages of hydrogen going to atmosphere or flare, which would cause waste of valuable product and GHG emissions. Moreover, depending on hydrogen production technology used upstream (electroliser, SMR, Auto Thermal Reformer, pyrolysis, H2 carrier, Nuclear), other compounds can be part of the mixture as contaminants of the process gas or function as specific components, for example in the event that hydrogen compression is part of existing process, such as a refinery process or other industrial plant processes. The other components can be directed to different exit points, for different uses, to create a circular economy.

[0039] While aspects of the invention have been described in terms of various specific embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes, and omissions are possible without departing form the spirit and scope of the claims. In addition, unless specified otherwise herein, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.

Claims

CLAIMS1. A hydrogen leakage recovery system (1), the system (1) comprising: at least one turbomachinery unit (11) comprising a gas turbine, or a turbo expander; and a recovery unit (12) fluidically coupled with said at least one turbomachinery unit (11), the recovery unit (12) comprising: a separator (121) configured to receive a mixture of hydrogen and other compounds leaked from the turbomachinery unit (11), and to separate the hydrogen from the other compounds so as to obtain a hydrogen stream, and a compressor (123) fluidically coupled with the separator (121), the compressor (123) being configured to receive the hydrogen stream from the separator (121) and to compress the hydrogen stream so as to obtain a compressed hydrogen stream, wherein the compressor (123) is further configured to deliver at least a portion of the compressed hydrogen stream to at least one of: the at least one turbomachinery unit (11), a first exit point (13) of the leakage recovery system (1) for user distribution, and an external component (30) fluidically coupled with the hydrogen leakage recovery system (1), preferably wherein the external component (30) comprises at least one of: a gas turbine, an external fuel cell, and a refuelling station; and wherein the recovery unit (12) is fluidically coupled with a plurality of output lines comprising: a return line (116) for directing the at least a portion of the compressed hydrogen stream to the at least one turbomachinery unit (11), a distribution line (117) for directing the at least a portion of the compressed hydrogen stream to the first exit point (13) of the leakage recovery system (1), and a usage line (118) for directing the at least a portion of the compressed hydrogen stream to the external component (30).

2. The hydrogen leakage recovery system (1) of the preceding claim, wherein the output line comprises a controlling valve (16, 17, 18).

3. The hydrogen leakage recovery system (1) of any one of the preceding claims, wherein the recovery unit (12) further comprises a purifier (122) for removing impurities from the hydrogen stream, the purifier (122) being fluidically coupled to at least one of: the compressor (123), and the separator (121) for providing a purified stream of hydrogen.

4. The hydrogen leakage recovery system (1) of any one of the preceding claims, wherein the other compounds comprise at least one of the following: oxygen, methane, nitrogen, and water.

5. The hydrogen leakage recovery system (1) of any one of the preceding claims, wherein the recovery unit (12) is configured to obtain a stream of other compounds.

6. The hydrogen leakage recovery system (1) of any one of the preceding claims, wherein the recovery unit (12) is fluidically coupled to an output line (115) configured to direct the stream of other compounds to a second exit point (14) of the hydrogen leakage recovery system (1) for user distribution.

7. The hydrogen leakage recovery system (1) of any one of the preceding claims, wherein the at least one turbomachinery unit (11) comprises a multi stage compressor system for compressing hydrogen including a seal assembly that is configured to receive a sealing gas stream for containment of hydrogen within the multi stage compressor system, wherein the sealing gas stream comprises a nitrogen stream.

8. The hydrogen leakage recovery system (1) of the preceding claim, wherein the multi stage compressor system further comprises: one or more vent for collecting said mixture leaked from the at least one turbomachinery unit (11); and one or more exhaust lines (114-1, 114-2) fluidically coupled to said one or more vent and said recovering unit (12) to direct the leaked flow of mixture toward said recovery unit (12).

9. The hydrogen leakage recovery system (1) of any one of the preceding claims, further comprising one or more supply lines for supply the at least one turbomachinery unit (11) with hydrogen.

10. A method (100) of operating a hydrogen leakage recovery system (1) as defined in any one of the preceding claims, the method comprising:receiving (101) at recovery system (12) a mixture of hydrogen and other compounds from the turbomachinery unit (11); separating (102) using the separator (121) the hydrogen from the other compounds so as to obtain a hydrogen stream; receiving (104) the hydrogen stream at the compressor (123) fluidically coupled with the separator (121); and compressing (105) the hydrogen stream using said compressor (123).

11. The method (100) of claim 10, wherein the compressor (123) is fluidically coupled with a purifier (122) and the method (100) further comprises purifying (103) the hydrogen stream with the purifier (122).

12. The method (100) of claim 10 or claim 11, further comprising delivering (106) at least a portion of the separated hydrogen stream to at least one of: the at least one turbomachinery unit (11), a first exit point (13) of the leakage recovery system (1), and an external unit (30) fluidically coupled with the hydrogen leakage recovery system (1), preferably wherein the external unit (30) comprises at least one of: a gas turbine, an external fuel cell, and a refuelling station.

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