Alkanes dehydrogenation process with hydrogen cofeeding

Abstract

The disclosure concerns an alkane dehydrogenation process remarkable in that it comprises the steps of (a) providing a first stream comprising one or more alkanes; (b) providing a second stream comprising hydrogen; (c) mixing the first stream and the second stream so as to generate a feedstream; (d) providing at least one proton-conducting catalytic membrane, each proton-conducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer; (e) feeding within the anode of said one or more proton-conducting catalytic membranes under alkane dehydrogenation conditions the feedstream generated at step (c); and (f) recovering a first effluent comprising at least one or more alkenes.

Description

[0001] Alkanes dehydrogenation process with hydrogen cofeeding

[0002] Technical field

[0003] The present disclosure relates to an alkanes dehydrogenation process.

[0004] Technical background

[0005] Alkanes dehydrogenation reactions are usually carried out without hydrogen extraction, limiting therefore the industrial processes to about 50% conversion. In addition, such reactions lead to significant and fast coking of the catalyst. Industrial processes require therefore either continuous decoking (with H2 or water). H2 produced must be separated from the product stream after the reaction.

[0006] In US20200248321 , a membrane reactor for conducting the dehydrogenation of alkanes to alkenes presents one or more tubes lined with one or more reactive ceramic membranes or layered throughout the one or more tubes. The membrane reactor allows a heated feed of alkanes to come into contact with the one or more ceramic membranes, wherein an alkane would react therewith, allowing alkenes to continue to flow through the one or more tubes and out of the system in reactor effluent feed, while hydrogen generated from the reaction of the alkane with the membrane would pass through the membrane and be physically separated.

[0007] In EP2534721 , WO2011098525 and WO2014187978, proton-conducting ceramic membrane were used with a tubular reactor. The proton-conducting membrane forms a layered structure of a porous and non-porous mixed metal oxide as a support and the a dehydrogenation catalyst can be deposited on said structure, either adhering or feely lieing on it.

[0008] The proton-conducting membrane are functioning thanks to the electricity and subsequently thanks to electrons transport.

[0009] The objective of this disclosure is therefore to provide an alkanes dehydrogation process that uses a proton-conducting membrane for allowing hydrgogen extraction and for which its efficiency is improved.

[0010] Summary

[0011] According to a first aspect, the disclosure relates to an alkane dehydrogenation process remarkable in that it comprises the following steps: a) providing a first stream comprising one or more alkanes; b) providing a second stream comprising hydrogen; c) mixing the first stream and the second stream so as to generate a feedstream; d) providing at least one proton-conducting catalytic membrane, each protonconducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer; e) feeding within the anode of said one or more proton-conducting catalytic membranes under alkane dehydrogenation conditions the feedstream generated at step (c); f) recovering a first effluent comprising at least one or more alkenes; g) optionally, recovering a second effluent comprising hydrogen.

[0012] Surprisingly, as a hydrogen is provided into the feedstream that is then fed to the anode of the one or more proton-conducting catalytic membranes, there is the activation of the protons transport in addition to the electrons transport which is activated thanks to the electricity. Subsquently, the conversion of the alkane dehydrogenation process is improved.

[0013] More particularly, the disclosure relates to an alkane dehydrogenation process remarkable in that it comprises the following steps: a) providing a first stream comprising one or more alkanes; b) providing a second stream comprising hydrogen; c) mixing the first stream and the second stream so as to generate a feedstream; d) providing at least one proton-conducting catalytic membrane, each protonconducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer; wherein the anode comprises at least one dehydrogenation catalyst; e) feeding within the anode of said one or more proton-conducting catalytic membranes under alkane dehydrogenation conditions the feedstream generated at step (c); f) recovering a first effluent comprising at least one or more alkenes; g) recovering at the cathode a second effluent comprising hydrogen; and providing said second effluent at step (b) as the second stream comprising hydrogen.

[0014] It has been found that the alkane dehydrogenation process of the present disclosure allows not only to recover one or more alkanes, but also hydrogen that can then be combined to perform the alkane dehydrogenation process and activate said alkane dehydrogenation process. This is interesting since the process of the present disclosure produces its own hydrogen that is required for its own improvement. The alkane dehydrogenation process

[0015] Advantageously, the feedstream generated at step (c) comprises hydrogen and one or more alkanes, wherein the hydrogen is at a molar fraction ranging between 0.01 and 0.1 , preferably between 0.025 and 0.05.

[0016] Advantageously, step (g) is carried out, and the second effluent is provided at step (b) as the second stream comprising hydrogen.

[0017] Advantageously, the alkane dehydrogenation conditions of step (e) comprise a temperature ranging between 400°C and 900°C, preferably between 425°C and 875°C, more preferably between 450°C and 850°C, even more preferably between 475°C and 825°C, most preferably between 500°C and 800°C, or between 525°C and 775°C, or between 550°C and 750°C, or between 575°C and 725°C, or between 600°C and 700°C.

[0018] Advantageously, the alkane dehydrogenation conditions of step (e) comprise a pressure ranging between 0.01 MPa and 1 MPa, preferably between 0.05 MPa and 0.9 MPa, more preferably between 0.09 MPa and 0.8 MPa, or between 0.1 MPa and 0.6 MPa.

[0019] Advantageously, the alkane dehydrogenation conditions of step (e) comprise a space velocity of at least 150 Nml / h / g, or of at least 200 Nml / h / g, or of at least 250 Nml / h / g, or of at least 300 Nml / h / g, or of at least 350 Nml / h / g, or of at least 400 Nml / h / g, or of at least 450 Nml / h / g, or of at least 500 Nml / h / g. For example, the alkane dehydrogenation conditions comprise a space velocity ranging between 150 Nml / h / g and 1000 Nml / h / g, or between 200 Nml / h / g and 1000 Nml / h / g, or between 250 Nml / h / g and 1000 Nml / h / g, or between 300 Nml / h / g and 1000

[0020] Nml / h / g, or between 350 Nml / h / g and 1000 Nml / h / g, or between 400 Nml / h / g and 1000

[0021] Nml / h / g, or between 450 Nml / h / g and 1000 Nml / h / g, or between 500 Nml / h / g and 1000

[0022] Nml / h / g.

[0023] Advantageously, the alkane dehydrogenation conditions of step (e) comprise providing an electrical current between the anode and the porous cathode of the one or more protonconducting catalytic membranes. With preference, said electrical current has a density of at least 0.10 A / cm2as measured by ampere meter / power supply instrument and divided by membrane surface or calculated from conductivity measurements (from electrochemical impedance spectroscopy, EIS), more preferably of at least 0.15 A / cm2, even more preferably of at least 0.20 A / cm2, most preferably of at least 0.25 A / cm2, even most preferably of at least 0.30 A / cm2, or of at least 0.35 A / cm2. For example, said electrical current has a density ranging between 0.10 A / cm2and 0.75 A / cm2as measured by ampere meter / power supply instrument and divided by membrane surface or calculated from conductivity measuremnets (from electrochemical impedance spectroscopy, EIS), more preferably between 0.15 A / cm2and 0.70 A / cm2, even more preferably between 0.20 A / cm2and 0.65 A / cm2, most preferably between 0.25 A / cm2and 0.60 A / cm2, or between 0.25 A / cm2and 0.55 A / cm2, or between 0.25 A / cm2and 0.50 A / cm2, or between 0.30 A / cm2and 0.45 A / cm2. With preference, said electrical current has electric potential ranging between 0.4 V and 1.8 V as measured by voltmeter / power supply instrument, more preferably between 0.5 V and 1.0 V

[0024] Advantageously, the stream provided at step (a) further comprises steam. With preference, the amount of steam is ranging between 1 vol.% and 15 vol.% based on the total volume of the stream provided at step (a) ; more preferably ranging between 2 vol.% and 10 vol.%.

[0025] For example, the process further comprises the step of providing steam into the stream provided at step (a). Said step of providing steam is performed continuously or in a pulsed manner (namely at intervals), preferably in a pulsed manner.

[0026] Advantageously, the one or more alkanes of the first stream are selected from one or more linear alkanes or one or more cyclic alkanes. With preference, said one or more alkanes of the first stream are selected from ethane, propane, butane, pentane, hexane, cyclohexane, methyl-cyclohexane, cyclopentane, methyl-cyclopentane, decalin, perhydro-dibenzyltoluene, dodecahydroW-ethyl carbazole or any mixtures thereof. More preferably, one alkane of the first stream is propane.

[0027] The one or more catalysts of the one or more proton-conducting catalytic membranes.

[0028] The one or more proton-conducting catalytic membranes comprises one or more catalysts, in particular one or more dehydrogenation catalysts.

[0029] For example, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts, one or more metal oxide-based catalysts, one or more zeolites, one or more transition metal carbides, one or more transition metal nitrides, one or more carbon nanotubes, or any mixtures thereof. With preference, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts, one or more metal oxide-based catalysts, one or more zeolites, or any mixtures thereof. More preferably, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts. For example, the one or more zeolites are selected from the group of CHA, MFI families or any mixtures thereof. For example, the one or more zeolites are doped with one or metals selected from Mo, W, Fe, V, Cr or any mixtures thereof. For example, the one or more metal-based catalysts and / or the one or more metal oxide-based catalyst comprises one or more metals selected from Pd, Pt, Sn, Mo, W, Fe, V, Cr or any mixtures thereof.

[0030] The anode

[0031] Advantageously, the anode comprises one or more channels, each of said channels comprising said at least one dehydrogenation catalyst.

[0032] With preference, said one or more channels are flared depth channels or rectangular channels.

[0033] Advantageously, the anode is made of one or more first metals and / or one or more spinels.

[0034] With preference, the one or more first metals are selected from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd, Au, Mn or any mixtures thereof, more preferably from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd or any mixtures thereof; even more preferably from Cu, Fe, Cr, Ag, Ni, Mo, or any mixtures thereof, most preferably from Cu, Fe, Cr, Ag, Ni or any mixtures thereof, such as Cu, Fe, Cr, Ni or any mixtures thereof, or such as Cu, Fe, Cr or any mixtures thereof, or such as Cu and / or Ag.

[0035] For example, the one or more first metals and / or the one or more spinels are doped with one or more dopants, preferably selected from Cu, Li, Cr or a mixture thereof.

[0036] For example, the anode is made of or comprises steel. More preferably, the anode is made of or comprises stainless steel, even more preferably ferritic stainless steel.

[0037] For example, the steel comprises between 60 wt.% and 80 wt.% of iron based on the total weight of the steel, preferably between 63 wt.% and 75 wt.% of iron.

[0038] For example, the steel comprises between 11 wt.% and 18 wt.% of chromium based on the total weight of the steel, preferably between 12 wt.% and 17 wt.%.

[0039] For example, the steel comprises between 10 wt.% and 14 wt.% of nickel based on the total weight of the steel, preferably between 11 wt.% and 13 wt.%.

[0040] For example, the steel comprises between 1 wt.% and 3 wt.% of molybdenum. For example, the steel comprises less than 0.15 wt.% of carbon based on the total weight of the steel, preferably less than 0.12 wt.%.

[0041] For example, the steel comprises at least 60 wt.% of iron and between 11 wt.% and 18 wt.% of chromium based on the total weight of the steel. With preference, the steel also comprises less than 0.15 wt.% of carbon based on the total weight of steel; preferably less than 0.12 wt.%.

[0042] For example, the steel comprises between 60 wt.% and 80 wt.% of iron, between 11 wt.% and 18 wt.% of chromium and less than 0.15 wt.% of carbon, based on the total weight of the steel.

[0043] For example, the anode is devoid of pores.

[0044] Advantageously, the anode has a thickness ranging between 3 mm and 6 mm as designed by SolidWorks software, preferably between 3.5 mm and 5.5 mm.

[0045] The electrolyte layer

[0046] Advantgeously, the electrolyte layer of the one or more proton-conducting catalytic membranes provided at step (d) comprises one or more perovskite materials with one or more cations selected from Ba, Ce, Zr, Y, La, Sr, Mn, Fe, Eu, Tb, Ni, Yb, Pr, Sm, Zn, Gd, Er, Co, Nd, or any mixtures thereof; with preference, said one or more cations are selected from Ba, Ce, Zr, Y, Ni, or any mixtures thereof; more preferably, said one or more cations are selected from Ba, Ce, Zr, Y, or any mixtures thereof.

[0047] For example, the electrolyte layer comprises one or more perovskite materials with an electrical conductivity ranging between 10'4S / cm and 10'3S / cm as determined by electrochemical impedance spectroscopy measurements performed at 600°C under an atmosphere comprising Ar and H2 in a ratio 75 / 25.

[0048] Advantageously, the electrolyte layer has a thickness ranging between 20 pm and 40 pm as determined by scanning electron microscopy, preferably between 25 pm and 35 pm.

[0049] The cathode

[0050] For example, the porous cathode comprises a mixture of one or more electrolytes and one or more second metals. For example, the one or more second metals are selected from Ni, Fe, Co, Pd, Pt, or any mixtures thereof, more preferably Ni. With preference, the amount of the one or more second metals is ranging between 50 wt.% and 70 wt.% of the total weight of said mixture, more preferably between 55 wt.% and 65 wt.%. For example, the amount of nickel is ranging between 50 wt.% and 70 wt.% of the total weight of said mixture, more preferably between 55 wt.% and 65 wt.%.

[0051] For example, the porous cathode is a macroporous layer.

[0052] Advantageously, the porous cathode has a thickness ranging between 30 pm and 50 pm as determined by scanning electron microscopy, preferably between 35 pm and 45 pm.

[0053] The one or more proton-conducting catalytic membranes

[0054] Advantageously, the one or more proton-conducting catalytic membranes provided at step (b) are one or more co-ionic catalytic membranes.

[0055] For example, water is co-fed into the feedstream generated at step (c) before step (d).

[0056] Advantageously, the at least one proton-conducting catalytic membrane has a tubular shape or is planar. With preference, the at least one proton-conducting catalytic membrane is planar.

[0057] Advantageously, the proton-conducting catalytic membrane presents a hydrogen extraction ratio ranging between 0.20 and 0.99, or between 0.25 and 0.90, at a temperature of at least 500°C and / or at a pressure of at most 0.1 MPa, the hydrogen extraction ratio being simulated by computational fluid dynamics (CFD) and / or quantified by gas chromatography (GC) during the reaction; with preference, the proton-conducting catalytic membrane presents a hydrogen extraction ratio ranging between 0.20 and 0.99, or between 0.25 and 0.90, at a temperature of at least 550°C and / or at a pressure of at most 0.05 MPa.

[0058] Description of the figures

[0059] Figure 1 : Scheme of the three layers forming a proton-conducting catalytic membrane which is particularly suitable to carry out the alkane dehydrogenation process in accordance with the present disclosure.

[0060] Figure 2: Scanning electron microscopy image of the proton-conducting catalytic membrane which is particularly suitable to carry out the alkane dehydrogenation process in accordance with the present disclosure. Figure 3: Scheme of a propane dehydrogenation (PDH) process carried out with the proton-conducting catalytic membrane.

[0061] Figure 4: Scheme of a rectangular channel arranged in the anode of a dehydrogenation reactor of the present disclosure.

[0062] Figure 5: Scheme of a flared depth channel arranged in the anode of a dehydrogenation reactor of the present disclosure, the flared depth channel having a surface area of the outlet larger than the surface area of the inlet.

[0063] Figure 6: Representation of the mechanism when a co-ionic catalytic membrane is used.

[0064] Figure 7: Electrochemical Impedance Spectroscopy (EIS) measurements of the electrolyte used in the present disclosure. Z’ and Z”” are respectively the real and the imaginary part of the impedance, each part corresponding to the two phases of the electrical impedance. The real part corresponds to the resistance R while the imaginary part corresponds to the reactance X

[0065] Figure 8: Zoom-in of figure 7 at the zone of the intersect of the curves with the abscissa. Figure 9: Conductivity measurement of the electrolytes used in the present disclosure. The electrolytes 1A and 1 B have been pre-calcined and then sintered at 700°C while the electrolyte 2A has been sintered at 700°C.

[0066] Figure 10: CFD simulation showing the evolution of the conversion of propane into propylene in function of the molar fraction of hydrogen that is cofed with the feed.

[0067] Figure 11 : Scheme of the installation according to the preferred embodiment of the present disclosure to conduct a polypropylene manufacturing process perthe present disclosure.

[0068] Figure 12: Sheme of the installation according to another embodiment of the present disclosure to conduct a polypropylene manufacturing process per the present disclosure.

[0069] Detailed description

[0070] For the disclosure, the following definitions are given:

[0071] The terms "comprising", "comprises" and "comprised of" as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms "comprising”, "comprises" and "comprised of" also include the term “consisting of”.

[0072] The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g., 1 to 5 can include 1 , 2, 3, 4, 5 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of endpoints also includes the recited endpoint values themselves (e.g., from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

[0073] Zeolite codes (e.g., CHA...) are defined according to the “Atlas of Zeolite Framework Types", 6threvised edition, 2007, Elsevier, to which the present application also makes reference.

[0074] As used herein, the term “C# hydrocarbons”, wherein “#” is a positive integer, is meant to describe all hydrocarbons having # carbon atoms. C# hydrocarbons are sometimes indicated as just C#.

[0075] The symbol “=” in the term “C#= hydrocarbon” indicates that the hydrocarbon concerned is an olefin or an alkene, and the notation “=” symbolises the carbon-carbon double bond. For instance, “C6=” stands for “C6 olefin”, or for “olefins comprising 6 carbon atoms”.

[0076] The term “steam” is used to refer to water in the gas phase, which is formed when water boils.

[0077] The term “transition metal” refers to an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell (IIIPAC definition). According to this definition, the transition metals are Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, and Cn.

[0078] The metals Ga, In, Sn, TI, Pb and Bi are considered “post-transition” metals.

[0079] The metals Au, Ag, Ru, Rh, Pd, Os, Ir and Pt show outstanding oxidation resistance and are considered “noble” metals. Other metals can be considered “non-noble” metals.

[0080] The term “alkali metal” refers to an element classified as an element from group 1 of the periodic table of elements (or group IA), excluding hydrogen. According to this definition, the alkali metals are Li, Na, K, Rb, Cs and Fr.

[0081] The term “alkaline earth metal” refers to an element classified as an element from group 2 of the periodic table of elements (or group HA). According to this definition, the alkaline earth metals are Be, Mg, Ca, Sr, Ba and Ra.

[0082] The term “rare earth elements” refer to the fifteen lanthanides, as well as scandium and yttrium. The 17 rare-earth elements are cerium (Ce), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), holmium (Ho), lanthanum (La), lutetium (Lu), neodymium (Nd), praseodymium (Pr), promethium (Pm), samarium (Sm), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb), and yttrium (Y).

[0083] The space velocity (Nml / h / g) is measured in term of the volumetric flow rate (Nml / h) of the reactant at 0°C and 1.01 bar per gram of catalyst (g-1). The volumetric flow rate of a fluid is expressed in Nml / h (“N” stands for “Normalized”), which corresponds to 1 cm3NTp / h.

[0084] The feed flow (T / h) is measured by a flowmeter and corresponds to the amount of ton per hour that is flowing.

[0085] The particular features, structures, characteristics or embodiments may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments.

[0086] The present disclosure relates to an alkane dehydrogenation process remarkable in that it comprises the following steps: a) providing a first stream comprising one or more alkanes; b) providing a second stream comprising hydrogen; c) mixing the first stream and the second stream so as to generate a feedstream; d) providing at least one proton-conducting catalytic membrane, each protonconducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer; e) feeding within the anode of said one or more proton-conducting catalytic membranes under alkane dehydrogenation conditions the feedstream generated at step (c); and f) recovering a first effluent comprising at least one or more alkenes.

[0087] The cofeeding of hydrogen (H2) wth the first stream comprising one or more alkanes is used to activate the transport of protons in the one or more proton-conducting catalytic membranes. Thefore, the cofeeding with hydrgogen comes in addition to the electricity that must be provided to activate the one or more porton-conducting catalytic membranes and therefore to perfom the dehydrogenation reaction of the one or more alkanes.

[0088] More particularly, the disclosure relates to an alkane dehydrogenation process remarkable in that it comprises the following steps: a) providing a first stream comprising one or more alkanes; b) providing a second stream comprising hydrogen; c) mixing the first stream and the second stream so as to generate a feedstream; d) providing at least one proton-conducting catalytic membrane, each protonconducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer; wherein the anode comprises at least one dehydrogenation catalyst; e) feeding within the anode of said one or more proton-conducting catalytic membranes under alkane dehydrogenation conditions the feedstream generated at step (c); f) recovering a first effluent comprising at least one or more alkenes; g) recovering at the cathode a second effluent comprising hydrogen; and providing said second effluent at step (b) as the second stream comprising hydrogen

[0089] For example, the one or more alkanes can be selected from one or more linear alkanes, and / or from one or more cyclic alkanes. For example, the one or more alkanes can be selected from ethane, propane, butane, pentane, hexane, cyclohexane, methyl-cyclohexane, cyclopentane, methyl-cyclopentane, decalin, perhydro-dibenzyltoluene, dodecahydro- / V-ethyl carbazole or a mixture thereof. With preference, one alkane of the first stream is propane, which is therefore dehydrogenated into propene. It is noted that methyl-cyclohexane, decaline, perhydro- dibenzyltoluene and dodecahydro- / V-ethyl carbazole are commonly known as liquid organic hydrogen carrier (LOHC) which acts as storage media for hydrogen. This indicates that the alkane dehydrogenation process of the present disclosure can be efficient in activating such LOHCs.

[0090] The feedstream which is generated at step (c) can comprise hydrogen and one or more alkanes, wherein the hydrogen is at a molar fraction ranging between 0.01 and 0.1 , preferably between 0.025 and 0.05. It is remarkable that only a small quantity of hydrogen is necessary to provide an improvement of the efficiency of the one or more proton-conducting catalytic membranes.

[0091] Optionally, a step (g) of recovering a second effluent comprising hydrogen can be carried out. When this step is carried out, the second effluent can be recycled and be used for example to trigger and to active the protons transport of the one or more proton-conducting catalytic membranes. So the second effluent can thus be provided at step (b) as the second stream comprising hydrogen. Advantageously, the alkane dehydrogenation conditions of step (e) comprise a temperature ranging between 400°C and 900°C, preferably between 425°C and 875°C, more preferably between 450°C and 850°C, even more preferably between 475°C and 825°C, most preferably between 500°C and 800°C, or between 525°C and 775°C, or between 550°C and 750°C, or between 575°C and 725°C, or between 600°C and 700°C.

[0092] Advantageously, the alkane dehydrogenation conditions of step (e) comprise a pressure ranging between 0.01 MPa and 1 MPa, preferably between 0.05 MPa and 0.9 MPa, more preferably between 0.09 MPa and 0.8 MPa, or between 0.1 MPa and 0.6 MPa.

[0093] Advantageously, the alkane dehydrogenation conditions of step (e) comprise a space velocity of at least 150 Nml / h / g, or of at least 200 Nml / h / g, or of at least 250 Nml / h / g, or of at least 300 Nml / h / g, or of at least 350 Nml / h / g, or of at least 400 Nml / h / g, or of at least 450 Nml / h / g, or of at least 500 Nml / h / g. For example, the alkane dehydrogenation conditions comprise a space velocity ranging between 150 Nml / h / g and 1000 Nml / h / g, or between 200 Nml / h / g and 1000 Nml / h / g, or between 250 Nml / h / g and 1000 Nml / h / g, or between 300 Nml / h / g and 1000

[0094] Nml / h / g, or between 350 Nml / h / g and 1000 Nml / h / g, or between 400 Nml / h / g and 1000

[0095] Nml / h / g, or between 450 Nml / h / g and 1000 Nml / h / g, or between 500 Nml / h / g and 1000

[0096] Nml / h / g.

[0097] Advantageously, the alkane dehydrogenation conditions of step (e) comprise providing an electrical current between the anode and the porous cathode of the one or more protonconducting catalytic membranes. With preference, said electrical current has a density of at least 0.10 A / cm2as measured by ampere meter / power supply instrument and divided by membrane surface or calculated from conductivity measurements (from electrochemical impedance spectroscopy, EIS), more preferably of at least 0.15 A / cm2, even more preferably of at least 0.20 A / cm2, most preferably of at least 0.25 A / cm2, even most preferably of at least 0.30 A / cm2, or of at least 0.35 A / cm2. For example, said electrical current has a density ranging between 0.10 A / cm2and 0.75 A / cm2as measured by ampere meter / power supply instrument and divided by membrane surface or calculated from conductivity measuremnets (from electrochemical impedance spectroscopy, EIS), more preferably between 0.15 A / cm2and 0.70 A / cm2, even more preferably between 0.20 A / cm2and 0.65 A / cm2, most preferably between 0.25 A / cm2and 0.60 A / cm2, or between 0.25 A / cm2and 0.55 A / cm2, or between 0.25 A / cm2and 0.50 A / cm2, or between 0.30 A / cm2and 0.45 A / cm2. With preference, said electrical current has electric potential ranging between 0.4 V and 1.8 V as measured by voltmeter / power supply instrument, more preferably between 0.5 V and 1.0 V Advantageously, the stream provided at step (a) further comprises steam. With preference, the amount of steam is ranging between 1 vol.% and 15 vol.% based on the total volume of the stream provided at step (a) ; more preferably ranging between 2 vol.% and 10 vol.%. For example, the process further comprises the step of providing steam into the stream provided at step (a). Said step of providing steam is performed continuously or in a pulsed manner (namely at intervals), preferably in a pulsed manner.

[0098] It is interesting that the cofeeding of hydrogen works well to improve to dehydrogenation reaction of the one or more alkanes with every kind of proton-conducting catalytic membranes. Thus, the one or more proton-conducting catalytic mebranes can have a tubular shape or can be planar.

[0099] Using one or more planar proton-conducting catalytic membranes provides some advantages. Indeed, it has been noticed that when the dehydrogenation reactor module is designed to reduce gas polarization, by being planar, it is still possible to improve the extracting capability of the proton-conducting catalytic membrane. Such proton-conducting catalytic membrane further minimizes coking formation and therefore preserves the activity of the one or more dehydrogenation catalysts.

[0100] For example, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts, one or more metal oxide-based catalysts, one or more zeolites, one or more transition metal carbides, one or more transition metal nitrides, one or more carbon nanotubes, or any mixtures thereof. With preference, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts, one or more metal oxide-based catalysts, one or more zeolites, or any mixtures thereof. More preferably, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts. For example, the one or more zeolites are selected from the group of CHA, MFI families or any mixtures thereof. For example, the one or more zeolites are doped with one or metals selected from Mo, W, Fe, V, Cr or any mixtures thereof. For example, the one or more metal-based catalysts and / or the one or more metal oxide-based catalyst comprises one or more metals selected from Pd, Pt, Sn, Mo, W, Fe, V, Cr or any mixtures thereof.

[0101] It is of course advantageous to use one or more proton-conducting catalytic membranes which present a hydrogen extraction ratio ranging between 0.20 and 0.99, or between 0.25 and 0.90, at a temperature of at least 500°C and / or at a pressure of at most 0.1 MPa, the hydrogen extraction ratio being simulated by computational fluid dynamics (CFD) and / or quantified by gas chromatography (GC) during the reaction. With preference, the proton-conducting catalytic membrane presents a hydrogen extraction ratio ranging between 0.20 and 0.99, or between 0.25 and 0.90, at a temperature of at least 550°C and / or at a pressure of at most 0.05 MPa.

[0102] A particular useful proton-conducting catalytic membrane that can be used in the present process of dehydrogenation of one or more alkanes is described in the following. It is a protonconducting catalytic membrane remarkable in that it comprises an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer, and wherein the anode is an anode which comprises at least one dehydrogenation catalyst. The proton-conducting catalytic membrane acts as an extractive membrane that removes the hydrogen that is produced during a dehydrogenation process. In particular, it is a protonconducting membrane remarkable in that it comprise an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer, wherein the anode comprises at least one dehydrogenation catalyst and is devoid of pores, and wherein the electrolyte layer comprises one or more perovskite materials with one or more cations selected from Ba, Ce, Zr, Y, La, Sr, Mn, Fe, Eu, Tb, Ni, Yb, Pr, Sm, Zn, Gd, Er, Co, Nd, or any mixtures thereof. It is schematized in figures 1 and 3, and imaged by scanning electron microscopy in figure 2.

[0103] Such proton-conducting catalytic membrane can be prepared according to the following method. The method comprises the following steps: a) providing a mixture of one or more electrolytes and one or more second metals to form a solution of mixed oxides; b) pressing uniaxially the mixture provided at step (a) to form a porous cathode, for example at a force ranging between 30 kN and 50 kN, preferably between 35 kN and 45 kN; c) optionally, calcining said porous cathode d) providing one or more electrolytes; e) screen-printing said one or more electrolytes on the porous cathode or on the calcined porous cathode if step (c) is carried out, to obtain a porous cathode with an electrolyte layer; f) sintering said porous cathode with an electrolyte layer, to obtain a sintered porous cathode with an electrolyte layer; g) providing an anode made of one or more first metals and / or one or more spinels; h) depositing at least one dehydrogenation catalyst on said anode provided at step (g), so as to form a catalytic anode; assembling together the sintered porous cathode with an electrolyte layer of step (f) with the catalytic anode formed at step (h), preferably by sealing with one or more sealants, so as to obtain a proton-conducting catalytic membrane as defined above.

[0104] The screen-printing technology, used at step (e), is a printing technique where a mesh, for example a 21 mesh, is used to transfer an ink onto a substrate. In this case, the substrate is a porous cathode and the ink is made essentially of the electrolyte.

[0105] The steps (a) to (f) are the steps for preparing a sintered porous cathode with an electrolyte layer of a proton-conducting membrane or of a proton-conducting catalytic membrane.

[0106] Before step (a), an activation step can be carried out under activation conditions on the oxidized form of the one or more second metals. For example, the activation conditions comprise providing a reduction atmosphere comprising preferably between 15 vol.% and 50 vol.% of hydrogen and between 85 vol.% and 50 vol.% of an inert gas based on the total volume of the reduction atmosphere. For example, the inert gas is Ar, He, N2 or a mixture thereof, preferably Ar. For example, the activation conditions comprise a temperature ranging between 600°C and 800°C, preferably between 650°C and 750°C. For example, the activation conditions comprise a reduction time ranging between 5 hours and 15 hours, preferably between 7 hours and 13 hours. With preference, a calcination step is carried out before said activation step, preferably at a temperature ranging between 600°C and 800°C, more preferably between 650°C and 750°C. For example, the calcination step is carried out under an inert gas atmosphere, such as under Ar, He, N2 or a mixture thereof, preferably under Ar.

[0107] The one or more electrolytes provided at step (a) can be a solid solution of at least two perovskite materials. The mixture of step (a) can further comprise one or more polar aprotic solvents, such as one or more of acetone, dimethyl formamide, dimethyl sulfoxide, or a mixture thereof, preferably acetone.

[0108] The mixture provided at step (a) can further comprise, to favour the pressing, one or more polymers selected from polyvinyl alcohol (PVA) or poly(methyl methacrylate) (PMMA), preferably polyvinyl alcohol (PVA). For example, the mixture provided at step (a) comprises said one or more polymers and mixed oxides at a ratio ranging between 1 / 0.050 and 1 / 0.100, preferably between 1 / 0.060 and 1 / 0.090, more preferably between 1 / 0.070 and 1 / 0.080.

[0109] Step (a) can be performed by grinding the mixture of one or more electrolytes and one or more second metals, preferably for at least 12 hours, more preferably for a time ranging between 18 hours and 36 hours, even more preferably ranging between 20 hours and 32 hours. After step (a) and before step (b), a drying step can be performed. For example, the drying step is performed at a temperature ranging between 40°C and 80°C, preferably between 50°C and 70°C.

[0110] The one or more first metals are advantageously selected from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd, Au, Mn or any mixtures thereof, more preferably from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd or any mixtures thereof; even more preferably from Cu, Fe, Cr, Ag, Ni, Mo, or any mixtures thereof, most preferably from Cu, Fe, Cr, Ag, Ni or any mixtures thereof, such as Cu, Fe, Cr, Ni or any mixtures thereof, or such as Cu, Fe, Cr or any mixtures thereof, or such as Cu and / or Ag. The one or more first metals and / or the one or more spinels can be doped with one or more dopants, preferably selected from Cu, Li, Cr or a mixture thereof.

[0111] The one or more second metals are advantageously selected from Ni, Fe, Co, Pd, Pt, or any mixtures thereof, more preferably Ni.

[0112] When step (c) is carried out, said step (c) can be performed at a temperature ranging between 600°C and 800°C, preferably between 650°C and 750°C; and / or during a time ranging between 5 hours and 15 hours, preferably between 7 hours and 13 hours.

[0113] The one or more electrolytes provided at step (a) and / or at step (d) can be or comprise one or more perovskite materials with one or more cations selected from Ba, Ce, Zr, Y, La, Sr, Mn, Fe, Eu, Tb, Ni, Yb, Pr, Sm, Zn, Gd, Er, Co, Nd, or any mixtures thereof; with preference, said one or more cations are selected from Ba, Ce, Zr, Y, Ni, or any mixtures thereof; more preferably, said one or more cations are selected from Ba, Ce, Zr, Y, or any mixtures thereof. For example, they are or comprise one or more perovskite materials with an electrical conductivity ranging between 10'4S / cm and 10'3S / cm as determined by electrochemical impedance spectroscopy measurements performed at 600°C under an atmosphere comprising Ar and H2 in a ratio 75 / 25. Advantageously, the one or more electrolytes provided at step (d) are the same as the one or more electrolytes provided in the mixture with one or more second metals.

[0114] The step (f) of sintering is the process of compacting and forming a solid mass by pressure and / or heat without melting the solid mass to its point of liquefaction. Step (f) can be performed at a temperature ranging between 1300°C and 1700°C, preferably between 1350°C and 1650°C, more preferably between 1400°C and 1600°C. Step (f) can be performed for a time of at least 5 hours, preferably during 10 hours and 15 hours. The steps (g) and (i) are the steps of making an anode on the electrolyte layer of the sintered porous cathode, the anode comprising ideally one or more dehydrogenation catalysts provided at step (h) so that the proton-conducting membrane is a proton-conducting catalytic membrane and can be used for example in a dehydrogenation process.

[0115] Before step (h) a step of forming one or more channels within the anode provided at step (g) can be carried out. With preference, said step of forming one or more channels is performed by electroforming or electroplating the anode provided at step (g). For example, said step of forming one or more channels is performed by chemical vapour deposition (CVD), physical vapour deposition (PVD), thermal spraying, microfabrication by etching, photolithography, tridimensional printing (such as fused deposition modelling, stereolithography or selective laser sintering), machining (such as milling, drilling or stamping), or any combination thereof.

[0116] Before step (i), a step of covering the electrochemical cell of step (f) with a layer of the same one or more first metals as those making the anode provided at step (g) can be carried out. The step (i) is advantageously performed by sealing together the electrochemical cell of step (f) with the catalytic anode formed at step (h) with one or more sealants. For example, the one or more sealants are one or more sealing tapes and / or one or more sealing pastes, more preferably one or more sealing tapes.

[0117] The anode

[0118] The anode is an electroconductive layer. The anode comprises at least one dehydrogenation catalyst and is devoid of pores.

[0119] For example, the anode is made of one or more first metals, and / or of one or more spinels ( / .e., MgAhCL). This is an electroconductive layer, where hydrogen is transformed into protons (H+), following the chemical equation (1):

[0120] H22 H++ 2e-

[0121] With preference, the one or more first metals are selected from from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd, Au, Mn or any mixtures thereof, more preferably from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd or any mixtures thereof; even more preferably from Cu, Fe, Cr, Ag, Ni, Mo, or any mixtures thereof, most preferably from Cu, Fe, Cr, Ag, Ni or any mixtures thereof, such as Cu, Fe, Cr, Ni or any mixtures thereof, or such as Cu, Fe, Cr or any mixtures thereof, or such as Cu and / or Ag. Silver is the highest conducting metals while copper is the cheapest. The one or more first metals and / or the one or more spinels can be preferably doped with one or more dopants which can be selected from Cu, Li, Cr or a mixture thereof. Advantageously, the anode is made of or comprises steel.

[0122] For example, the anode is made of or comprises stainless steel, more preferably ferritic stainless steel.

[0123] For example, the steel comprises between 60 wt.% and 80 wt.% of iron based on the total weight of the steel, preferably between 63 wt.% and 75 wt.% of iron.

[0124] For example, the steel comprises between 11 wt.% and 18 wt.% of chromium based on the total weight of the steel, preferably between 12 wt.% and 17 wt.%.

[0125] For example, the steel comprises between 10 wt.% and 14 wt.% of nickel based on the total weight of the steel, preferably between 11 wt.% and 13 wt.%.

[0126] For example, the steel comprises between 1 wt.% and 3 wt.% of molybdenum, such as 2 wt.% of molybdenum.

[0127] For example, the steel comprises less than 0.15 wt.% of carbon based on the total weight of the steel, preferably less than 0.12 wt.%.

[0128] For example, the steel comprises between 60 wt.% and 80 wt.% of iron, between 11 wt.% and 18 wt.% of chromium and less than 0.15 wt.% of carbon, based on the total weight of the steel.

[0129] For example, the steel comprises at least 60 wt.% of iron and between 11 wt.% and 18 wt.% of chromium based on the total weight of the steel. With preference, the steel also comprises less than 0.15 wt.% of carbon based on the total weight of steel; preferably less than 0.12 wt.%.

[0130] In particular, the steel comprises at least 60 wt.% of iron, between 11 wt.% and 18 wt.% of chromium, and less than 0.15 wt.% of carbon, based on the total weight of the steel. More particularly, the steel comprises at least 60 wt.% of iron, between 11 wt.% and 18 wt.% of chromium, less than 0.15 wt.% of carbon, between 10 wt.% and 14 wt.% of nickel and between 1 wt.% and 3 wt.% of molybdenum, based on the total weight of the steel

[0131] Advantageously, the anode has a thickness ranging between 3 mm and 6 mm as designed by SolidWorks software, preferably between 3.5 mm and 5.5 mm. A reactor housing, made for example in Inconel or steel, can encompass the anode, such as an anode made of copper. When the anode is made of steel, there is no need of reactor housing. Therefore, the thickness of the whole reactor is ranging between 1 cm and 2 cm. As no reactor housing is required, the reactor is lighter compared to a reactor with an anode in copper which required an Inconel or a steel housing.

[0132] For example, the anode is non-porous.

[0133] Advantageously, the one or more dehydrogenation catalysts comprise one or more metalbased catalysts, one or more metal oxide-based catalysts, one or more zeolites, one or more transition metal carbides, one or more transition metal nitrides, one or more carbon nanotubes, or any mixtures thereof. With preference, the one or more dehydrogenation catalysts comprise one or more metal-based catalysts, one or more metal oxide-based catalysts, one or more zeolites, or any mixtures thereof. For example, the one or more zeolites are selected from the group of CHA, MFI families or any mixtures thereof. For example, the one or more zeolites are doped with one or metals selected from Mo, W, Fe, V, Cr or any mixtures thereof. For example, the one or more metal-based catalysts and / or the one or more metal oxide-based catalyst comprises one or more metals selected from Pd, Pt, Sn, Mo, W, Fe, V, Cr or any mixtures thereof. The metal-based catalysts, such as the catalysts comprising one or more metals selected from Pd, Pt, Sn, Mo, W, Fe, V, Cr or any mixtures thereof, or preferably selected from Pd, Pt, Sn or any mixture thereof, are preferred as dehydrogenation catalysts. Such metal-based catalysts can be supported, for example onto AI2O3, SiC>2, TiC>2, CeC>2 or any mixture thereof, more preferably AI2O3 and / or SiC>2.

[0134] The fact that the anode comprises the one or more dehydrogenation catalysts allows for maximisation of the contact surface between the one or more dehydrogenation catalysts and the electrolyte, leading therefore to an improvement of the extraction capability of the membrane.

[0135] The electrolyte layer

[0136] The electrolyte layer acts as a protons transport layer. It is noted that since the electrolyte is a medium containing ion and that is electrically conducting upon the movement of those ions, the alkanes such as the propane, or the products of the dehydrogenation reaction, namely the corresponding alkenes, such as the propene, cannot cross the electrolyte layer. Only the hydrogen under the form of proton (H+) will be able to cross the electrolyte layer and then extracted upon application of an electrical current.

[0137] For example, the electrolyte of the electrolyte layer comprises one or more perovskite materials with an electrical conductivity ranging between 10'4S / cm and 10'3S / cm as determined by electrochemical impedance spectroscopy measurements performed at 600°C under an atmosphere comprising Ar and H2 in a ratio 75 / 25.

[0138] For example, the electrolyte of the electrolyte layer comprises one or more perovskite materials having a general formula ABX3, wherein A and B are cations with different oxidation states and X is an anion. The A-cation occupies the center of the unit cell, while the B cation and the X anions (commonly oxygen) are arranged at the corners and the edges of the unit cell, respectively.

[0139] For example, the electrolyte of the electrolyte layer is or comprises one or more perovskite materials with one or more cations selected from Ba, Ce, Zr, Y, La, Sr, Mn, Fe, Eu, Tb, Ni, Yb, Pr, Sm, Zn, Gd, Er, Co, Nd, or any mixtures thereof. With preference, said one or more cations are selected from Ba, Ce, Zr, Y, Ni, or any mixtures thereof. More preferably, the one or more cations are selected from Ba, Ce, Zr, Y, or any mixtures thereof. For example, the electrolyte of the electrolyte layer is or comprises at least two perovskite materials, preferably in the form of a solid solution.

[0140] For example, the electrolyte of the electrolyte layer comprises one or more perovskite materials being BaCeCh and BaZrCh in the form of a solid solution. BaCeCh exhibits higher proton conductivity than BaZrCh, but can suffer chemical instability. On the other hand, BaZrCh presents adequate stability under different conditions but presents a significant grain boundary resistance in addition to the high sintering temperature that causes Ba evaporation and the subsequent loss of transport properties. The solid solution of both BaCeCh and BaZrCh, corresponding to the electrolyte BaCeo.3Zro.5Yo.2O3, can overcome the disadvantages of both materials taken independently.

[0141] Advantageously, the electrolyte layer has a thickness ranging between 20 pm and 40 pm as determined by scanning electron microscopy, preferably between 25 pm and 35 pm.

[0142] With preference, the anode, which is an anode, comprises one or more channels arranged in parallel to each other, each of said channels comprising the one or more dehydrogenation catalysts. For example, the anode can advantageously comprise two channels, preferably 4 channels, more preferably 8 channels, or 9 channels or 10 channels. A configuration in which an anode comprises 4 channels is schematized in figure 3. The fact that the one or more dehydrogenation catalysts are surrounded by the electrolyte further contributes to the extractive capabilities of the proton-conducting catalytic membrane of the present disclosure. For example, each of said one or more channels has a cross-section amounting to at least 2 cm2, or to at least 2.5 cm2. For example, at least a part of said one or more channels are rectangular channels (see figure 4), flared depth channels (see figure 5), flared width channels, bended channels, or corrugated channels; more preferably, all of said one or more channels are rectangular channels, flared depth channels, flared width channels, bended channels, or corrugated channels; even more preferably, all of said one or more channels are rectangular channels or flared depth channels, most preferably, all of said one or more channels are flared depth channels. In particular, flared depth channels are channels with a surface area of the outlet larger than the surface area of the inlet, the inlet and the outlet being defined according to the sense of the feed flow, for example the inlet is where the compound to be dehydrogenated (e.g., the propane) is introduced into the proton-conducting catalytic membrane and the outlet is where the one or more products of the dehydrogenation reaction (e.g., propylene, cracked products (such as ethane and / or methane), coke) are exiting the proton-conducting catalytic membrane.

[0143] The porous cathode

[0144] For example, the porous cathode comprises a mixture of an electrolyte and one or more second metals. This porous layer ensures the recombination of protons (H+) into hydrogen (H2), following the chemical equation (2): 2H++ 2e_— > H2

[0145] With preference, the one or more second metals are selected from Ni, Fe, Co, Pd, Pt, or any mixtures thereof, more preferably Ni. For example, the amount of the one or more second metals is ranging between 50 wt.% and 70 wt.% of the total weight of said mixture, more preferably between 55 wt.% and 65 wt.%. Thus, in the case where nickel would be selected as the preferred cathodic metal, the amount of nickel in the mixture forming the porous cathode is ranging between 50 wt.% and 70 wt.% of the total weight of said mixture, more preferably between 55 wt.% and 65 wt.%.

[0146] Advantageously, the porous cathode is a porous layer with a thickness ranging between 30 pm and 50 pm as determined by scanning electron microscopy, preferably between 35 pm and 45 pm.

[0147] Advantageously, the one or more proton-conducting catalytic membranes provided at step (d) are one or more co-ionic catalytic membranes. Figure 6 displays a representation mechanism involving a co-ionic catalytic membrane. This is particularly efficient when the stream provided at step (a) further comprises steam. When a co-ionic membrane is used, water is co-fed into the feedstream generated at step (c), so that such feedstream comprises the one or more alkanes, hydrogen and water. The co-feeding is performed before step (d). The water is injected through the porous cathode of catalytic membrane, so that the water is split into hydrogen and oxygen. Then the oxygen anions can cross the membrane, so as to react with part of the hydrogen that is formed at the anode side, namely within the anode of the catalytic membrane. Such co-ionic catalytic membrane conducts therefore protons versus electrons and oxygen anions. Typical materials suitable for the co-ionic catalytic membranes are perovskites ABO3, such as oxides of Co, oxides of CoFe, oxides of Zr, oxides of BaZr, oxides of CaZr doped with one or more of Sr, Ba, Co, Cu, Fe, Cr, La, Ni, Ca.

[0148] With preference, the control of the quantity of coke that is formed can also occur when water is co-fed into the feedstream, and without the co-ionic catalytic membrane, but only in presence of the proton-conducting catalytic membrane.

[0149] Other membranes could be used, such as polymeric membranes including polyimides, polybenzimidazoles, silicon-based polymers; inorganic membranes including palladium, platinium or alloys-based membranes; zeolitic membranes; ceramic membranes comprising zirconia or alumina; composites membranes made of several materials that are above described, such as one or more perovskite materials with one or more cations selected from Ba, Ce, Zr, Y, La, Sr, Mn, Fe, Eu, Tb, Ni, Yb, Pr, Sm, Zn, Gd, Er, Co, Nd, or any mixtures thereof; organic membranes such as Metal-Organic Frameworks (MOFs); carbon nanotubes membranes (carbon molecular sieve (CMS) membranes).

[0150] Test and determination methods

[0151] Scanning electron microscopy (SEM) analysis was carried out by using a field-emission scanning electron microscope using a Zeiss Ultra 55 fitted with a field emission gun using an accelerating voltage of 30.0 kV. All samples before the SEM characterization were covered with a conductive layer (Pt or Au).

[0152] Electrochemical Impedance Spectroscopy (EIS) measurements were performed to validate the transport properties of the developed membranes. EIS measurements were measured using a SolarTron instrument and by applying an electrical current through the membrane by means of two silver electrodes EIS allows obtaining the resistance of the electrolyte, while equation (1) allows the determination of the electrical conductivity of the material. wherein o is the electrical conductivity, R is the electrical resistance and <|) is the area of electrode and t is the thickness of the electrode. The hydrogen extraction ratio, which is the quantity of hydrogen extracted on the quantity of hydrogen formed, is obtained by simulations using computational fluid dynamics (CFD) technique and / or is determined by using gas chromatography (GC) technique. The hydrogen extraction ratio is calculated and / or determined on the basis of the reactant conversion, for example the propane conversion and in the case of GC, the quantity of hydrogen formed, or in the case of CFD, the theoretical quantity of hydrogen generated.

[0153] With respect to the simulations made by CFD technique, they were performed with COMSOL Multiphysics 5.6 software on SYS-6018R-MTR Super server, with an Intel Xeon CPU E5-2640 v4 processor (clock speed 2.4 GHz, 40 CPUs) and 131 Gb RAM running Windows server edition 2016 (64-bit) as an operating system. For the gas flow, Navier-Stokes equations with the respective correction for the porous catalytic bed has been considered. Transport of species has been modelled using averaged-mixture model with propane, propylene and H2 as species. The density of the gas mixture has been estimated considering a mixture of ideal gases, and the viscosity has been calculated using the Wilke model. The porosity and permeability are two key factors that govern the fluid flow in the porous region and the permeability for a packed bed with randomly distributed spherical particles was calculated using the Carman-Kozeny model. According to the publication of Tong Y. et al (Int. J. of Hydrogen Energy, 2022, 47, 12067-12073), electrochemical hydrogen pumps are devices based upon proton-conducting electrolytes that offer 100% selectivity to hydrogen and allow for easy control of the hydrogen separation rate by simply adjusting the applied direct current. The tortuosity was estimated considering the inverse of the square root of the porosity. The binary gas diffusion coefficient has been calculated with an empirical equation based on the Fuller kinetic gas theory, and it was corrected with the ratio of the porosity to tortuosity. The mesh performed was based on tetrahedral elements, where the element size was calibrated for fluid dynamics. The calculations were carried out using the Parallel Direct Solver (PARDISO) with parameter continuation to assure convergence. The relative tolerance of the method is 0.001.

[0154] The thickness of the anode has been designed using SolidWorks software which is a solid modelling computer-aided design (CAD) and computer-aided engineering (CAE) application published by Dassault Systems.

[0155] The feed flow of the second stream and / or of the purge stream has been determined using a SolarTron ISA flowmeter.

[0156] The ampere meter / power supply instrument and the voltmeter / power supply instrument used for determining respectively the electrical current density and the electrical potential is a SolarTron power supply module. Examples

[0157] The embodiments of the present disclosure will be better understood by looking at the different examples below.

[0158] Preparation of the electrolyte BaCeo.3Zro.5Yo.2O3 under a form of a solid solution of BaCeOs and BaZrOs.

[0159] 1) Grind the precursors separately for 60 hours. The employed precursors were: BaCO3(99.8% 1-micron powder. Alfa Aesar Ref: 14341 , 1kg, CAS: 513-77-9), YSZ (ZrO2 / Y2O3) (8%), CeO2(REacton, 99.9% (REO), 5-micron powder. Alfa Aesar Ref: 11328, 1 kg, CAS: 1306-38- 3) and Y2O3(99.9995%. ABCR Ref: AB102097, 100 g, CAS: 1314-36-9).

[0160] 2) Mix the different precursors in adequate proportions in acetone to fulfil the stoichiometry of the desired compound and grind for 24 hours. The following amount of precursors have been weighted:

[0161] BaCO3^ 17.06 g

[0162] YSZ 6.14 g

[0163] CeO2^ 4.46 g

[0164] Y2O3^ 1.09 g

[0165] 3) Dry by heating at 60 °C in a furnace.

[0166] 4) Sieve the oxide mixture with a particle size of 200 pm.

[0167] 5) The oxide mixture is uniaxially pressed at 40 kN in the shape of a disc (disc diameter: 30 mm).

[0168] 6) Sinter discs at 1100°C for 10 hours.

[0169] 7) Repeat steps 4-6 twice then, grind the mixture for 24 hours.

[0170] 8) The calcined oxide mixture is pressed on 20 mm discs at 30kN.

[0171] 9) Sinter the obtained discs at 1565°C for 12 hours.

[0172] Preparation of the cathode NiO-BaCeo.3Zro.5Yo.2O3 under a form of a solid solution of BaCeOs and BaZrOs

[0173] 25 g of the solid solution of BaCeO3and BaZrO3is then mixed and ground for 15 hours in acetone together with 37.5 g NiO (99% - metal basis; 325 mesh powder, Alfa Aesar Ref: 12359, 250 g, CAS 1313-99-1). After a step of drying by heating at 60°C in a furnace, the mixed oxides are mixed with polyvinyl alcohol (PVA) to favour the pressing. The mixture has a ratio of mixed oxides / PVA 1 / 0.075. It is then ground with agate mortar before being pressed uniaxially at 40 kN in the shape of a disc (disc diameter: 20 mm). Optionally, the cathode is calcined at 700°C for 10h.

[0174] Then, the electrolytes are coated on the cathode by using screen-printing technique using a 21 -mesh to obtain a porous cathode with an electrolyte layer. The support is a pressed powder transformed into a disk. In membranes, the screen-printing procedure consists of squeezing the slurry “ink” (electrolyte) to pass through a 21 -mesh screen to print it on the cathode. After drying the layer (temperature of 80°C), it is possible to deposit extra layers. The typical thickness of the obtained layer is around 30 pm. After that, the different layers and cathode are sintered at 1565 °C temperature to obtain an efficient attachment between the cathode and the electrolyte and to afford a sintered porous cathode with an electrolyte layer.

[0175] Prior to be used, the NiO species have been reduced under hydrogen to form Ni+. This activation step is carried out in a 25 vol.% H2 atmosphere in argon at 700°C for 10 hours, optionally with a pre-calcination at 700°C under pure argon for 10 hours before the activation step.

[0176] Preparation of the proton-conducting membrane

[0177] Then, an anodic layer is coated on the electrolyte layer of the sintered porous cathode.

[0178] The anodic layer is an anode comprising Ag. A silver conducting paint (DYNALOY® 342) was indeed obtained from Merck (CAS 7440-22-4) and painted by hand.

[0179] Figure 7 shows a representative example of the electrochemical impedance spectra used to calculate the electrical conductivity. Three batches proton-conducting membrane, namely of electrochemical cells (BaCeo.3Zro.5Yo.2O3 on uncalcined NiO-BaCeo.3Zro.5Yo.2O3) layered with an Ag anode have been used. The curve “1” corresponds to wet conditions test ( / .e., 3 vol.% of water in the H2 / Ar feed) while the curves “2” and “3” are under the same dry conditions ( / .e., H2 / Ar feed without water) (reproducibility test). The tests have been made at 700°C. The intersect with the abscissa (that can be viewed on the zoom of figure 7 provided at figure 8) gives a value used for plotting figure 9.

[0180] Figure 9 shows the conductivity of three batches of proton-conducting membranes, namely of electrochemical cells (1A: BaCeo.3Zro.5Yo.2O3 on uncalcined NiO-BaCeo.3Zro.5Yo.2O3 with an activation preceded by a calcination; 1 B: BaCeo.3Zro.5Yo.2O3 on uncalcined NiO- BaCeo.3Zro.5Yo.2O3 with an activation without calcination; and 2A: (BaCeo.3Zro.5Yo.2O3 on calcined NiO-BaCeo.3Zro.5Yo.2O3) layered with an Ag anode. 1A: NiO-BaCeo.3Zro.5Yo.2O3 is pre-calcinated at 700°C under pure argon for 10 hours before NiO being activated with a 25 vol.% H2 atmosphere in argon at 700°C for 10 hours.

[0181] 1 B: NiO is activated with a 25 vol.% H2 atmosphere in argon at 700°C for 10 hours, without a pre-calcination step.

[0182] 2A: NiO-BaCeo.3Zro.5Yo.2O3 is pre-calcinated at 700°C under pure argon for 10 hours before addition of BaCeo.3Zro.5Yo.2O3. Then the NiO is reduced under H2 at 700°C for 10 hours.

[0183] Preparation of the proton-conducting catalytic membrane

[0184] The preparation of the reactor assembly is made as following:

[0185] 25 g of the solid solution of BaCeOs and BaZrOs is then mixed and ground for 15 hours in acetone together with 37.5 g of NiO (99% - metal basis; 325 mesh powder, Alfa Aesar Ref: 12359, 250 g, CAS 1313-99-1). After a step of drying by heating at 60°C in a furnace, the mixed oxides are mixed with polyvinyl alcohol (PVA) to favour the pressing. The mixture has a ratio of mixed oxides / PVA 1 / 0.075. It is then ground with agate mortar before being pressed uniaxially at 40 kN in the shape of a disc (disc diameter: 20 mm). Optionally, the cathode is calcined at 700°C for 10h.

[0186] Then, the electrolytes are coated on the cathode by using screen-printing technique using a 21 -mesh to obtain a porous cathode with an electrolyte layer. The support is a pressed powder transformed into a disk. In membranes, the screen-printing procedure consists of squeezing the slurry “ink” (electrolyte) to pass through a 21 -mesh screen to print it on the cathode. After drying the layer (temperature of 80°C), it is possible to deposit extra layers. The typical thickness of the obtained layer is around 30 pm. After that, the different layers and cathode are sintered at 1565 °C temperature to obtain an efficient attachment between the cathode and the electrolyte and to afford a sintered porous cathode with an electrolyte layer.

[0187] Prior to be used, the NiO species have been reduced under hydrogen to form Ni+. This activation step is carried out in a 25 vol.% H2 atmosphere in argon at 700°C for 10 hours, optionally with a pre-calcination at 700°C under pure argon for 10 hours before the activation step.

[0188] Then, an anodic layer is coated on the electrolyte layer of the sintered porous cathode.

[0189] The anodic layer is an anode comprising Cu, with channels and a dehydrogenation catalyst comprised within said channels.

[0190] The sintered porous cathode with an electrolyte layer is covered with copper, using ionsputtering. The ion-sputtering conditions involve a Pfeiffer Classic 250 deposition system equipped with two RF (13.56 MHz) power sources, each capable of delivering up to 25 W of 1 power. The system utilizes a Cu target for the deposition process and operates at room temperature. The deposition is carried out under a pure Ar atmosphere with a pressure range of 2.6.1 O'2to 7.4.10’2mbar.

[0191] A channeled support in copper comprising a dehydrogenation catalyst is then prepared by 3D printing of the anode. The 3D printer is a Markeforged MetalX printer using a Bound Powder Filament made of copper (90%) and a polymer (10%). The 3D printing allows to make linear channels. The obtained support is then calcined to remove the polymer at about 200°C and is sintered under Ar at about 900°C for 72h. Then, the channels of the support are filled by hands with 1.25 g of catalyst powder, namely of PtSnEu support on AI2O3 (0.5 wt.% of Pt, 2 wt.% of Eu and 3 wt.% of Sn).

[0192] The sintered porous cathode with an electrolyte layer covered with copper is thus placed on top of the channeled anode comprising the dehydrogenation catalyst and sealed with either GL1734 glass sealing paste (commercially available at Mo-Sci Corporation) or GM31107 glass sealant tape (commercially available at Schott AG) to obtain a proton-conducting catalytic membrane. The glass sealing paste is activated at 620°C for 4 hours, while the glass sealant tape is activated at 700°C for 2 hours.

[0193] The proton-conducting catalytic membrane is then placed into a reactor housing in Inconel alloy.

[0194] The initial geometry considered in this study consists of a series of rectangular microchannels arranged in parallel, with a length of 50 mm and a surface area of the inlet being equal to the surface area of the outlet (e.g., 25 mm2), as shown by figure 4. These channels have been filled with 1.25 g of catalyst ( / .e., PtSnEu supported on AI2O3) and equipped with a selective membrane to remove H2 on the top surface.

[0195] However, an optimized geometry study showed that the optimal extraction is performed having a flared depth channel as shown in figure 5 namely with a surface area of the outlet (e.g., 25 mm2) being larger than the surface area of the inlet (e.g.,10 mm2). In this experiment, the length of the channel has been fixed to 50 mm. These channels have been filled with 1.25 g of catalyst ( / .e., PtSnEu supported on AI2O3).

[0196] Dehydrogenation of alkanes

[0197] Table 1 is a simulation by CFD of the propane conversion and the hydrogen molar fraction at the outlet of a proton-conducting catalytic membrane presenting flared-depth channels having a length of 30 cm. The simulation has been made at a space velocity SV of 576 Nml / h / g. Table 1 : Simulation by CFD of the propane conversion and the hydrogen molar fraction at the oulet of the proton-conducting catalytic membrane.

[0198] The results of table 1 are displayed in figure 10, which therefore illustrates how the system behaves when a fraction of H2 is recirculated. In the absence of hydrogen fed into the system, the maxium current density that can be applied is limited by the initial region of the reactor. As the hydrogen molar fraction increases, this limitation is overcome, allowing for more effective H2 extraction, and enhancing the conversion. However, beyond a molar fraction of 0.05, the conversion is not improving anymore and is even starting to decrease. This is attributed to the additional hydrogen which decreases the kinetic rate. Therefore, the ideal hydrogen molar fraction is ranging between 0.025 and 0.050.

[0199] Implementaion in a propyplene manufacturing process

[0200] Hydrogen cofeeding can be implemented in different process, notably in a polypropylene manufacturing process.

[0201] Said polypropylene manufacturing process comprises the following steps: a) providing a first propylene stream, said first propylene stream optionally comprising one or more solvents; b) polymerizing the first propylene stream under polymerization conditions to form an effluent comprising polypropylene and at least propylene and propane and optionally the one or more solvents if any; c) separating the effluent to generate a first stream comprising polypropylene and a second stream comprising at least propylene and propane, and optionally a third stream comprising the one or more solvents if any; d) optionally, recycling the third stream if any; f) splitting the second stream to produce an overhead comprising propylene and a purge stream, said purge stream being a propane-rich stream further comprising propylene; g) optionally, recycling the overhead into the first propylene stream provided at step (a); wherein the process is remarkable in that it further comprises a first dehydrogenating step (h) and / or a second dehydrogenating step (e); wherein said first dehydrogenating step (h) is the step of dehydrogenating the purge stream produced at step (f) to enrich in propylene the purge stream; wherein said second dehydrogenating step (e) is carried out after the separation step (c) and before the spliiting step (f) and is the step of dehydrogenating the second stream generated at step (c) to enrich in propylene the second stream; and wherein said first and second dehydrogenating steps are each a propane dehydrogenation step producing respectively a first hydrogen effluent and a second hydrogen effluent, and wherein said first hydrogen effluent and / or said second hydrogen effluent are receovored and at least partially directed respectively in the purge stream and / or in the second stream.

[0202] Such process is carried out in an installation as described on figure 11 or 12. Said installation compries a polymerization zone 1 and a separation zone 3 which is downstream of the polymerization zone 1.

[0203] The polymerization zone 1 comprises a polymerization reactor 9. For example, there is an input line 23 for providing a first propylene stream as required by step (a). For example, polymer-grade propylene with a propylene content of at least 99 wt.% based on the total weight of the polymer-grade propylene, preferentially at least 99.5 wt.% is the first propylene stream. One or more catalysts, such as Ziegler-Natta catalyst or metallocene catalyst, typically titanium chlorides, one or more stabilizers such as H2, one or more inhibitors such as H2, and / or one or more solvents such as one or more organic solvents, and / or one or more diluents such as a C4, C5 or C6 alkanes, may be introduced into the polymerization reactor 9 as required, depending upon the specific polymerization technique being used. One or more polymerization reactors 9 can be involved in the process, with the individual reactors carrying out the same or different unit operations. The product manufactured may be any type of propylene polymer, including, but not limited to, homopolymers, such as a medium-or high- impact homopolymers; substituted, including halogenated, homopolymers; copolymers, such as random and block copolymers of ethylene and propylene; and terpolymers. For example, the polymerization step (b) is carried out in the liquid phase, resulting in the formation of polypropylene particles in suspension in the solvent, or in a gas phase, resulting in the formation of polypropylene powder entrained with the propylene gas.

[0204] It is noted that the reactor operating conditions and functioning are not critical to the disclosure and can vary from plant to plant. As shown in figures 11 and 12, the separation zone 3 comprises at least a polymer separation apparatus 21 and a splitter 11 with a bottom outlet 13, the polymer separation apparatus 21 being upstream to the splitter 11. There is a first line 5 between the polymerization reactor 9 and the polymer separation apparatus 21. The first line 5 is useful for conveying the products formed during the polymerizing step (b), namely an effluent comprising polypropylene and at least propylene ( / .e., the unreacted propylene) and propane, and optionally the one or more solvents if any to the polymer separation apparatus 21 , wherein the separating step (c) of the process is carried out.

[0205] For example, the polymer separation apparatus 21 can be one or more phase separation vessels (when the polymerizing step (b) is carried out in a liquid phase) or one or more cyclone separators (when the polymerizing step (b) is carried out a gas phase). The separation step (c) allows for the generation of a first stream of polypropylene that can be recovered through the polypropylene exit line 25, a second stream comprising at least propylene and propane and optionally a third stream comprising the one or more solvents if any. For example, the second stream comprising at least propylene and propane comprises after step (c) and / or before step (e) between 25 vol.% and 90 wt.% of propylene based on the total weight of the second stream, or between 30 vol.% and 85 wt.%, or between 35 vol.% and 80 wt.%.

[0206] An optional step (d) can be carried out to recycle the third stream comprising the one or more solvents. This is done via the recycling line 35. For example, the recycling line 35 can be directed to the polymerization zone 1 (not shown) to be mixed with the first propylene stream provided at step (a) and / or to downstream processes.

[0207] The installation is remarkable in that it comprises one or more first dehydrogenation reactors 15 arranged downstream of the bottom outlet 13 of the splitter and / or one or more second dehydrogenation reactors 16 arranged upstream of the splitter 11 ; each first and second dehydrogenation reactor (15, 16) comprising at least one proton-conducting catalytic membrane, each proton-conducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer, and wherein the anode comprises one or more channels, each of said channels comprising at least one dehydrogenation catalyst, wherein said one or more channels are flared depth channels or rectangular channels, and wherein said one or more channels are made in copper or steel. In a preferred embodiment, the installation comprises at least one first dehydrogenation reactor 15 that is arranged downstream of the bottom outlet 13 of the splitter, as depicted in figure 11. This allows the purge stream to be enriched with propylene.

[0208] In another embodiment, that can be complimentary to the above preferred embodiment, the installation can also comprise at least one second dehydrogenation reactor 16 arranged upstream to the splitter 11 , for example between the polymer separation apparatus 21 and the splitter. This dehydrogenation reactor 16, as depicted in figure 12, is used to convert the propane of the second stream into propylene. The second stream comprising at least propylene and propane is thus enriched in propylene.

[0209] The one or more first and / or second dehydrogenation reactors (15, 16) of the installation can also be used to extract the hydrogen generated during the dehydrogenation reaction. The hydrogen can then be recovered in an optional step through the first hydrogen effluent line 33 (figure 11) and / or through the second hydrogen effluent line 18 (figure 12).

[0210] A first hydrogen effluent recycled line 37 can be implemented, so that the first hydrogen effluent can be cofeeded with the purge stream being a propane-rich stream further comprising propylene, so that the protons transport of the one or more first dehydrogenation reactors 15 is activated.

[0211] A second hydrogen effluent recycled line 39 can be implemented, so that the second hydrogen effluent can be cofeeded with the second stream comprising at least propylene and propane, so that the protons transport of the one or more second dehydrogenation reactors 16 is activated.

Claims

CLAIMS1 . An alkane dehydrogenation process is characterized in that it comprises the following steps: a) providing a first stream comprising one or more alkanes; b) providing a second stream comprising hydrogen; c) mixing the first stream and the second stream so as to generate a feedstream; d) providing at least one proton-conducting catalytic membrane, each protonconducting catalytic membrane comprising an anode, an electrolyte layer disposed on top of the anode and a porous cathode disposed on top of the electrolyte layer; wherein the anode comprises at least one dehydrogenation catalyst; e) feeding within the anode of said one or more proton-conducting catalytic membranes under alkane dehydrogenation conditions the feedstream generated at step (c); f) recovering a first effluent comprising at least one or more alkenes; g) recovering at the cathode a second effluent comprising hydrogen; and providing said second effluent at step (b) as the second stream comprising hydrogen.

2. The alkane dehydrogenation process according to claim 1 is characterized in that the feedstream generated at step (c) comprises hydrogen and one or more alkanes, wherein the hydrogen is at a molar fraction ranging between 0.01 and 0.1 , preferably between 0.025 and 0.05.

3. The alkane dehydrogenation process according to claim 1 or 2 is characterized in that the alkane dehydrogenation conditions of step (e) comprise a temperature ranging between 400°C and 900°C.

4. The alkane dehydrogenation process according to any one of claims 1 to 3 is characterized in that the alkane dehydrogenation conditions of step (e) comprises providing an electrical current between the anode and the porous cathode of the one or more proton-conducting catalytic membranes.

5. The alkane dehydrogenation process according to claim 4, characterized in that said electrical current has a density of at least 0.10 A / cm2as measured by ampere meter and divided by membrane surface.

6. The alkane dehydrogenation process according to any one of claims 1 to 5 is characterized in that it comprises a step of providing steam into the feedstream generated at step (c) in a pulsed manner.

7. The alkane dehydrogenation process according to any one of claims 1 to 6 is characterized in that the stream provided at step (a) further comprises steam in an amount ranging between 1 vol.% and 15 vol.% of the total volume of the stream provided at step (a).

8. The alkane dehydrogenation process according to any one of claims 1 to 7 is characterized in that water is co-fed into the feedstream generated at step (c) before step (d).

9. The alkane dehydrogenation process according to any one of claims 1 to 8 is characterized in that the anode comprises one or more channels, each of said channels comprising said at least one dehydrogenation catalyst; with preference, said one or more channels are flared depth channels or rectangular channels.

10. The alkane dehydrogenation process according to any one of claims 1 to 9 is characterized in that the anode is made of one or more first metals.11 . The alkane dehydrogenation process according to claim 9 is characterized in that the one or more first metals are selected from Cu, Fe, Cr, Ag, Ni, Mo, Pt, Pd, Au, Mn or any mixtures thereof.

12. The alkane dehydrogenation process according to any one of claims 1 to 11 is characterized in that the anode is made of one or more spinels.

13. The alkane dehydrogenation process according to any one of claims 1 to 12 is characterized in that the electrolyte layer of the one or more proton-conducting catalytic membranes provided at step (d) comprises one or more perovskite materials with one or more cations selected from Ba, Ce, Zr, Y, La, Sr, Mn, Fe, Eu, Tb, Ni, Yb, Pr, Sm, Zn, Gd, Er, Co, Nd, or any mixtures thereof.

14. The alkane dehydrogenation process according to any one of claims 1 to 13 is characterized in that the at least one proton-conducting catalytic membrane has a tubular shape or is planar.

15. The alkane dehydrogenation process according to any one of claims 1 to 14 is characterized in that one alkane of the first stream is propane.

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