Process for converting alkanes into olefins in an electrically energized fluidized bed reactor

Abstract

The present disclosure relates to a process for carrying out a reaction of converting alkanes into olefins, the process comprising the steps of: (a) providing a stream comprising a light alkane feedstock having one or more alkanes and one or more oxidants selected from CO2 and / or COS; and providing at least one fluidized bed reactor, the fluidized bed reactor comprising at least two electrodes and a bed comprising particles; (b) fluidizing the particles of the bed to obtain a fluidized bed; and (c) heating the fluidized bed to a temperature in the range of 600°C to 1500°C to carry out the reaction; the process is remarkable in that step c) is carried out by passing an electric current through the fluidized bed; the particles of the bed comprise conductive particles, and at least 10% by weight of the particles are conductive particles and have a resistivity in the range of 0.001 to 500 Ohm.cm at 800°C.

Description

Technical Field

[0001] The present disclosure relates to processes for the conversion of alkanes to olefins (such as partial oxidation of alkanes and / or oxidative coupling of alkanes) in a fluidized bed reactor, where the reaction is carried out in the fluidized bed reactor without the need for an external heating device. The present disclosure aims to contribute to the replacement of heating devices based on fossil carbon. The present disclosure relates to the electrification of the chemical industry. Background Art

[0002] Climate change and the ongoing energy transition have made it necessary to develop new electrification processes for the production of, in particular, basic chemicals. Given the development of shale gas extraction, the conversion of light alkanes to olefins (or olefins) is one of the potentially cleaner opportunities to reduce dependence on crude oil-based products.

[0003] Olefins within the petrochemical industry can include any unsaturated hydrocarbon compound containing at least one carbon-carbon double bond. Olefins are widely used within the chemical industry due to their general reactivity and their ability to polymerize or oligomerize into longer-chain hydrocarbon products such as synthetic fuels.

[0004] Currently, short-chain olefins are typically produced using gaseous or liquid light hydrocarbons, which are steam cracked at temperatures between 750 °C and 950 °C. The cracked gas contains a variety of olefins and is immediately quenched to stop the numerous secondary (olefin-consuming) radical reactions within the off-gas. The various olefins can then be separated from the remaining quenched cracked gas via distillation.

[0005] Natural gas is a naturally occurring mixture of hydrocarbon gases (including methane) and contains up to approximately 20% concentrations of higher hydrocarbons (such as ethane) and impurities (such as carbon dioxide and hydrogen sulfide). Due to the hundreds of trillions of cubic feet of proven, unexploited natural gas reserves, natural gas potentially provides an abundant source of hydrocarbons. Unfortunately, except via pipeline, natural gas, or more specifically methane found in natural gas, is expensive to transport over long distances. Even in the case of using pipelines, methane requires a significant capital investment in the pipeline itself and generates significant operating expenses at the recompression stations required to maintain reasonable pipeline flow rates. However, the limitation of transportation to pipelines essentially relegates such methane sources to a regional supply role, meaning that unless there is local demand for methane, the natural gas supply is "stranded" - available for extraction but without local demand to make extraction economically attractive and practical.

[0006] Historically, methane has been converted into longer-chain hydrocarbons by steam reforming to provide synthesis gas (“syngas”), a mixture containing carbon monoxide and hydrogen, which is then used as a feedstock for the Fischer-Tropsch process that converts carbon monoxide and hydrogen into liquid hydrocarbons (often referred to as the “gas-to-liquid” or “GTL” process). Steam reforming can also process higher alkanes (e.g., ethane and propane) and has many commercial options. However, even with the Fischer-Tropsch process, the ability to convert methane into short-chain olefins such as ethylene is extremely limited.

[0007] The oxidative coupling of methane (“OCM”) reaction promotes the formation of olefins such as ethylene using an exothermic reaction of methane and oxygen on one or more catalysts according to the following equation:

[0008] 2CH4+O2→C2H4+2H2O

[0009] This reaction is exothermic and has historically been carried out at very high temperatures above 750 °C. Difficulties associated with reaction control have driven the search for alternative oxidants. Suitable alternatives involve compounds such as N2O, S2 (the gaseous form of sulfur, S8), CO2 (Angewandte Chemie, Volume 60, Issue 19, 2021, pp. 10502-10515; and Nature Chemistry, Volume 5, 2013, pp. 104-109) as mentioned in the compound academic literature.

[0010] 2CH4+S2→C2H4+2H2S

[0011] The conversion of higher alkanes accompanying methane in NG reservoirs by oxidative dehydrogenation encounters the same problems as the oxidative coupling of methane (Catalysis Science and Technology, Issue 6, 2016, pp. 5483-5493).

[0012] The present disclosure aims to provide large-scale solutions suitable for applications in industries such as the chemical industry for one or more problems encountered in the prior art. The present disclosure aims to facilitate the use of heating devices based on fossil carbon-based fuels in fluidized bed reactors. The present disclosure provides solutions for the conversion of alkanes into olefins in fluidized bed reactors, such as the partial oxidation reaction and / or oxidative coupling reaction of light alkanes. Summary of the Invention

[0013] According to a first aspect, the present disclosure provides a process for converting alkanes into olefins, the process comprising the following steps:

[0014] a) Provide a stream of a feedstock containing light alkanes, the stream of the feedstock containing light alkanes containing one or more alkanes, and one or more oxidants selected from carbon dioxide (CO2), carbonyl sulfide (COS), and any mixture thereof; and further provide at least one fluidized bed reactor, the fluidized bed reactor comprising at least two electrodes and a bed containing particles;

[0015] b) Fluidize the particles of the bed to obtain a fluidized bed; and

[0016] c) Heat the fluidized bed to a temperature in the range of 600 °C to 1500 °C to effect the conversion of the alkanes in the feedstock containing light alkanes to olefins;

[0017] d) Optionally collect the product of the reaction;

[0018] The process is remarkable in that step c) of heating the fluidized bed is carried out by passing an electric current through the fluidized bed; the particles of the bed comprise conductive particles and optionally particles of a catalytic composition; and based on the total weight of the particles of the bed, at least 10% by weight of the particles are conductive particles and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C.

[0019] Preferably, the conversion of alkanes to olefins is or comprises a partial oxidation reaction and / or an oxidative coupling reaction of the alkanes containing light alkanes.

[0020] Surprisingly, it has been found that the use of conductive particles in one or more electrically energized fluidized bed reactors allows the attainment and maintenance of a temperature sufficient to effect the partial oxidation reaction and / or the oxidative coupling reaction of the alkanes containing light alkanes. Although these reactions require high temperature conditions, such as temperature conditions in the range of 600 °C to 1500 °C, the reaction is carried out without the need for additional external heating means such as heating means in or around the reaction vessel of the fluidized bed reactor. The use of at least 10% by weight of conductive particles within the particles of the bed allows the minimization of heat loss upon application of a voltage. Due to the Joule effect, most (if not all) of the electrical energy is converted into heat for heating the reactor medium.

[0021] For example, the conductive particles are or comprise one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more carbon-containing particles, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0022] In a preferred embodiment, the conductive particles are or comprise one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, graphite, carbon black, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0023] Advantageously, the process further comprises a step d) of collecting the reaction product, wherein the product comprises one or more olefins and carbon monoxide. Step d) is carried out after step c).

[0024] In a preferred embodiment, the volumetric heat generation rate is greater than 0.1 MW / m 3 fluidized bed, more preferably greater than 1 MW / m 3 , especially greater than 3 MW / m 3 .

[0025] In a preferred embodiment, at least one fluidized bed reactor has no heating device. It should be understood that, except for the combination of the electrodes and the bed containing at least 10 wt% conductive particles, at least one fluidized bed reactor has no heating device. For example, at least one fluidized bed reactor comprises a container and has no heating device located around or inside the container. For example, at least one fluidized bed reactor has no heating device selected from an oven, a gas burner, a hot plate, or any combination thereof. For example, all fluidized bed reactors have no heating device selected from an oven, a gas burner, a hot plate, or any combination thereof.

[0026] For example, based on the total weight of the particles of the bed, the content of the conductive particles is in the range of 10 wt% to 100 wt%; preferably, 15 wt% to 95 wt%, more preferably 20 wt% to 90 wt%, even more preferably 25 wt% to 80 wt%, and most preferably 30 wt% to 75 wt%.

[0027] For example, based on the total weight of the particles of the bed, the content of the conductive particles is at least 12 wt% based on the total weight of the particles of the bed; preferably, at least 15 wt%, more preferably, at least 20 wt%; even more preferably at least 25 wt%, and most preferably at least 30 wt% or at least 40 wt% or at least 50 wt% or at least 60 wt%.

[0028] For example, the conductive particles have a resistivity in the range of 0.005 to 400 Ohm.cm at 800 °C, preferably in the range of 0.01 to 300 Ohm.cm at 800 °C; more preferably in the range of 0.05 to 150 Ohm.cm at 800 °C, and most preferably in the range of 0.1 to 100 Ohm.cm at 800 °C.

[0029] For example, the conductive particles have a resistivity of at least 0.005 Ohm.cm at 800 °C; preferably at least 0.01 Ohm.cm at 800 °C, more preferably at least 0.05 Ohm.cm at 800 °C; even more preferably at least 0.1 Ohm.cm at 800 °C, and most preferably at least 0.5 Ohm.cm at 800 °C.

[0030] For example, the conductive particles have a resistivity of at most 400 Ohm.cm at 800 °C; preferably at most 300 Ohm.cm at 800 °C, more preferably at most 200 Ohm.cm at 800 °C; even more preferably at most 150 Ohm.cm at 800 °C, and most preferably at most 100 Ohm.cm at 800 °C. The content of the conductive particles based on the total weight of the particles of the bed and the selection of the conductive particles with a given resistivity affect the temperature reached by the fluidized bed. Therefore, in the case where the target temperature is not reached, a person skilled in the art can increase the density of the particle bed, the content of the conductive particles based on the total weight of the particles of the bed, and / or select conductive particles with a lower resistivity to increase the temperature reached by the fluidized bed.

[0031] For example, the density of the bed of particles is expressed as the void fraction. The void fraction or bed porosity is the volume of the voids between the particles divided by the total volume of the bed. At the initial fluidization velocity, the void fraction is typically 0.4 to 0.5. In a fast fluidized bed, the void fraction can increase up to 0.98, where it is a lower value of about 0.5 at the bottom of the bed and higher than 0.9 at the top of the bed. The void fraction can be controlled by the linear velocity of the fluidizing gas and can be reduced by recycling solid particles collected at the top and fed back to the bottom of the fluidized bed, which compensates for the entrained solid particles from the bed.

[0032] The void fraction VF is defined as the volume fraction of voids in the bed of particles and is determined according to the following formula:

[0033]

[0034] where Vt is the total volume of the bed and is determined by the following formula

[0035] Vt = AH (2)

[0036] where A is the cross-sectional area of the fluidized bed and H is the height of the fluidized bed; and

[0037] where Vp is the total volume of the particles in the fluidized bed.

[0038] For example, the porosity of the bed is in the range of 0.5 to 0.8; preferably in the range of 0.5 to 0.7, more preferably in the range of 0.5 to 0.6. To increase the density of the bed of particles, the porosity is to be decreased.

[0039] For example, when measured by sieving according to ASTM D4513-11, the particles of the bed have an average particle size in the range of 5 to 300 μm, preferably in the range of 10 to 200 μm, and more preferably in the range of 20 to 200 μm or 30 to 150 μm.

[0040] Measurement by sieving according to ASTM D4513-11 is preferred. In the case where the particles have an average size below 20 μm, the average size can also be measured by laser scattering according to ASTM D4464-15.

[0041] For example, when measured by sieving according to ASTM D4513-11, the conductive particles of the bed have an average particle size in the range of 5 to 300 μm, preferably in the range of 10 to 200 μm, and more preferably in the range of 30 to 150 μm.

[0042] Preferably, the conductive particles of the bed are or comprise one or more selected from the following: graphite, carbon black, one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof; preferably, the content is 50 wt% to 100 wt% based on the total weight of the conductive particles of the bed; preferably, 60 wt% to 100 wt%; more preferably 70 wt% to 100 wt%; even more preferably 80 wt% to 100 wt%, and most preferably 90 wt% to 100 wt%.

[0043] Preferably, the conductive particles of the bed are or comprise one or more carbon-containing particles that are graphite.

[0044] Preferably, the conductive particles of the bed are or comprise one or more selected from the following: graphite, carbon black, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0045] Preferably, the conductive particles of the bed are or comprise one or more selected from the following: one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0046] For example, the conductive particles of the bed do not contain one or more carbon-containing particles selected from petroleum coke, carbon black, coke, or a mixture thereof.

[0047] In one embodiment, the conductive particles of the bed do not contain one or more carbon-containing particles selected from graphite, petroleum coke, carbon black, coke, or a mixture thereof. For example, the conductive particles of the bed do not contain graphite and / or carbon black. For example, the conductive particles of the bed do not contain petroleum coke and / or coke.

[0048] Alternatively, the conductive particles of the bed are or comprise graphite and one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0049] As an alternative, the conductive particles of the bed are one or more particles selected from the following: one or more metal alloys, one or more non-metallic resistors (provided that the non-metallic resistor is not silicon carbide), one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, graphite, carbon black, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, and / or one or more and / or mixed sulfides doped with one or more low-valent cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0050] For example, the conductive particles of the bed are or comprise one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, graphite, carbon black, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof, preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0051] For example, the conductive particles of the bed are or comprise graphite and one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0052] For example, the conductive particles of the bed are or comprise one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0053] For example, the conductive particles of the bed are or comprise one or more selected from the following: one or more non-metallic resistors, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof; preferably, the content is 50% to 100% by weight based on the total weight of the conductive particles of the bed; preferably, 60% to 100% by weight; more preferably 70% to 100% by weight; even more preferably 80% to 100% by weight, and most preferably 90% to 100% by weight.

[0054] Advantageously, the conductive particles of the bed comprise one or more metal alloys. For example, the one or more metal alloys are selected from Ni-Cr, Fe-Ni-Cr, Fe-Ni-Al, or a mixture thereof. Preferably, when the metal alloy contains at least chromium, the chromium content is at least 15 mol%, more preferably at least 20 mol%, even more preferably at least 25 mol%, and most preferably at least 30 mol% of the total molar content of the metal alloy containing at least chromium. Also advantageously, the iron content in the metal alloy is at most 2.0 mol%, preferably at most 1.5 mol%, more preferably at most 1.0 mol%, even more preferably at most 0.5 mol% based on the total molar content of the metal alloy.

[0055] For example, the one or more non-metallic resistive bodies are selected from silicon carbide (SiC), molybdenum disilicide (MoSi2), nickel silicide (NiSi), sodium silicide (Na2Si), magnesium silicide (Mg2Si), platinum silicide (PtSi), titanium silicide (TiSi2), tungsten silicide (WSi2), or a mixture thereof, preferably silicon carbide.

[0056] For example, the one or more metal carbides are selected from iron carbide (Fe3C) and / or molybdenum carbide (e.g., a mixture of MoC and Mo2C).

[0057] For example, the one or more transition metal nitrides are selected from zirconium nitride (ZrN), tungsten nitride (e.g., a mixture of W2N, WN, and WN2), vanadium nitride (VN), tantalum nitride (TaN), and / or niobium nitride (NbN).

[0058] For example, the one or more metal phosphides are selected from copper phosphide (Cu3P), indium phosphide (InP), gallium phosphide (GaP), sodium phosphide (Na3P), aluminum phosphide (AlP), zinc phosphide (Zn3P2), and / or calcium phosphide (Ca3P2).

[0059] Advantageously, the conductive particles of the bed comprise one or more superionic conductors. For example, the one or more superionic conductors are selected from LiAlSiO4, Li 10 GeP2S 12 , L i3.6 Si 0.6 P 0.4 O4, sodium superionic conductor (NaSICON) such as Na3Zr2PSi2O 12 , or sodium beta-alumina such as NaAl 11 O 17 , Na 1.6 Al 11 0 17.3 , and / or Na 1.76 Li 0.38 Al 10.62 0 17 .

[0060] For example, the one or more phosphate electrolytes are selected from LiPO4 or LaPO4.

[0061] For example, the one or more mixed oxides are ionic or mixed conductors doped with one or more low-valent cations. Advantageously, the mixed oxides are doped with one or more low-valent cations and are selected from oxides having a cubic fluorite structure, perovskite, and pyrochlore.

[0062] For example, the one or more mixed sulfides are ionic or mixed conductors doped with one or more low-valence cations.

[0063] For example, the conductive particles of the bed are or comprise one or more non-metallic resistors selected from silicon carbide, molybdenum disilicide, or mixtures thereof. For example, the conductive particles of the bed are or comprise silicon carbide.

[0064] For example, the conductive particles of the bed are or comprise a mixture of a non-metallic resistor that is silicon carbide and conductive particles different from silicon carbide. The presence of conductive particles different from silicon carbide in the bed is optional. It can be present as a starting material for heating the bed because it has been found that the resistivity of silicon carbide at room temperature is too high to start heating the bed. As an alternative to the presence of conductive particles different from silicon carbide, heat can be provided to the reactor for a defined time to initiate the reaction.

[0065] For example, silicon carbide is selected from sintered silicon carbide, nitride-bonded silicon carbide, recrystallized silicon carbide, reaction-bonded silicon carbide, and any mixtures thereof.

[0066] For example, the conductive particles of the bed are or comprise a mixture of a non-metallic resistor that is silicon carbide and conductive particles different from silicon carbide. Preferably, the conductive particles of the bed comprise 10 wt% to 99 wt%, preferably 15 wt% to 95 wt%, more preferably 20 wt% to 90 wt%, even more preferably 25 wt% to 80 wt%, and most preferably 30 wt% to 75 wt% of silicon carbide based on the total weight of the conductors in the bed.

[0067] For example, the conductive particles of the bed are or comprise a mixture of a non-metallic resistor that is silicon carbide and conductive particles different from silicon carbide, and the conductive particles different from silicon carbide are one or more carbon-containing particles and / or one or more mixed oxides doped with one or more low-valence cations, and / or one or more mixed sulfides doped with one or more low-valence cations.

[0068] For example, the conductive particles of the bed are or comprise a mixture of a non-metallic resistor that is silicon carbide and conductive particles different from silicon carbide, and the conductive particles different from silicon carbide are graphite and / or one or more mixed oxides doped with one or more low-valence cations, and / or one or more mixed sulfides doped with one or more low-valence cations.

[0069] For example, the conductive particles of the bed are or comprise one or more mixed oxides as ion conductors (i.e., doped with one or more low-valent cations); preferably, the mixed oxides are selected from:

[0070] - one or more oxides having a cubic fluorite structure and at least partially substituted with one or more low-valent cations preferably selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and / or

[0071] - one or more ABO3 perovskites having A and B trivalent cations, wherein the ABO3 perovskite is at least partially substituted with one or more low-valent cations preferably selected from Ca, Sr, or Mg at the A site and contains at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe, and / or mixtures thereof at the B site; and / or

[0072] - one or more ABO3 perovskites having A divalent cations and B tetravalent cations, wherein the ABO3 perovskite is at least partially substituted with one or more low-valent cations preferably selected from magnesium (Mg), scandium (Sc), yttrium (Y), neodymium (Nd), or ytterbium (Yb) or a mixture of different B elements at the B site; and / or

[0073] - one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, wherein the A2B2O7 pyrochlore is at least partially substituted with one or more low-valent cations preferably selected from Ca or Mg at the A site and contains at least one of Sn, Zr, and Ti at the B site.

[0074] For example, the conductive particles of the bed are or comprise one or more mixed sulfides as ion conductors (i.e., doped with one or more low-valent cations); preferably, the mixed sulfides are selected from:

[0075] - one or more sulfides having a cubic fluorite structure and at least partially substituted with one or more low-valent cations preferably selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and / or

[0076] - one or more ABS3 structures having A and B trivalent cations, wherein the ABS3 structure is at least partially substituted with one or more low-valent cations preferably selected from Ca, Sr, or Mg at the A site and contains at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe, and / or mixtures thereof at the B site; and / or

[0077] -One or more ABS3 structures having A divalent cations and B tetravalent cations, wherein the ABS3 structure is at least partially substituted at the B-site by one or more low-valence cations preferably selected from Mg, Sc, Y, Nd or Yb, or by a mixture of different B elements at the B-site; and / or

[0078] -One or more A2B2S7 structures having A trivalent cations and B tetravalent cations, wherein the A2B2S7 structure is at least partially substituted at the A-site by one or more low-valence cations preferably selected from Ca or Mg, and contains at least one of Sn, Zr and Ti at the B-site.

[0079] Preferably, based on the total number of atoms present in one or more oxides having a cubic fluorite structure, the degree of substitution in one or more mixed oxides doped with one or more low-valence cations and having a cubic fluorite structure is 1 to 15 atomic %, preferably 3 to 12 atomic %, more preferably 5 to 10 atomic %.

[0080] Preferably, based on the total number of atoms present in the one or more ABO3 perovskites having A and B trivalent cations, the one or more ABO3 perovskites having A divalent cations and B tetravalent cations, or the one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, the degree of substitution in the one or more mixed oxides doped with one or more low-valence cations is 1 to 50 atomic %, preferably 3 to 20 atomic %, more preferably 5 to 15 atomic %.

[0081] Preferably, based on the total number of atoms present in one or more oxides having a cubic fluorite structure, the degree of substitution in one or more mixed sulfides doped with one or more low-valence cations and having a cubic fluorite structure is 1 to 15 atomic %, preferably 3 to 12 atomic %, more preferably 5 to 10 atomic %.

[0082] Preferably, based on the total number of atoms present in the one or more ABS3 structures having A and B trivalent cations, the one or more ABS3 structures having A divalent cations and B tetravalent cations, or the one or more A2B2S7 structures having A trivalent cations and B tetravalent cations, the degree of substitution in one or more mixed sulfides doped with one or more low-valence cations is 1 to 50 atomic %, preferably 3 to 20 atomic %, more preferably 5 to 15 atomic %.

[0083] For example, the conductive particles of the bed are or comprise one or more metal alloys; preferably, the one or more metal alloys are selected from Ni-Cr, Fe-Ni-Cr, Fe-Ni-Al, or mixtures thereof.

[0084] Preferably, when the metal alloy contains at least chromium, the chromium content is at least 15 mol%, more preferably at least 20 mol%, even more preferably at least 25 mol%, and most preferably at least 30 mol% of the total molar content of the metal alloy containing at least chromium. Advantageously, the iron content in the metal alloy is at most 2.0 mol%, preferably at most 1.5 mol%, more preferably at most 1.0 mol%, even more preferably at most 0.5 mol% based on the total molar content of the metal alloy.

[0085] For example, the conductive particles of the bed are or comprise a mixture of a non-metallic resistor which is or comprises silicon carbide and particles different from silicon carbide, wherein the particles different from silicon carbide are or comprise graphite.

[0086] For example, the conductive particles of the bed are or comprise one or more carbon-containing particles which are graphite. Preferably, the graphite is graphite particles having an average particle size in the range of 5 to 300 μm, more preferably in the range of 10 to 200 μm, and most preferably in the range of 30 to 150 μm when measured by sieving according to ASTM D4513-11.

[0087] For example, the conductive particles of the bed are or comprise graphite and one or more conductive particles different from graphite and selected from one or more of the following: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, or any mixture thereof. Preferably, the conductive particles of the bed comprise 10 wt% to 99 wt% based on the total weight of the conductors in the bed; preferably 15 wt% to 95 wt%, more preferably 20 wt% to 90 wt%, even more preferably 25 wt% to 80 wt%, and most preferably 30 wt% to 75 wt% of graphite.

[0088] Advantageously, the bed contains particles of a catalyst composition, and the catalyst composition comprises one or more selected from rare earth oxides, rare earth sulfides, transition metal oxides, transition metal sulfides, and any mixture thereof, and the catalyst composition optionally comprises one or more dopants. Preferably, the one or more dopants comprise at least one alkali metal, alkaline earth metal, transition metal, post-transition metal, or rare earth metal carbonate or thiocarbonate, or any mixture thereof.

[0089] Advantageously, the bed contains particles of a catalytic composition, and the catalyst composition comprises one or more selected from Na-W-Mn / SiO2, NaCl-MnNa2WO4 / SiO2, La2O3-CeO2, Li / MgO, CaO-Sm2O3, KCl-SmCl3, CaO-NaCl / Na2CO3, CeO2 / ZnO, La2O3 / Al2O3, and FeS x thereof.

[0090] For example, the partial oxidation reaction and / or oxidative coupling reaction of alkanes is carried out at a temperature in the range of 500 °C to 2000 °C, more preferably 550 °C to 1700 °C, even more preferably 600 °C to 1500 °C, or 700 to 1300 °C; most preferably 800 °C to 1200 °C or 900 °C to 1400 °C; and even most preferably 1000 °C to 1500 °C.

[0091] For example, the partial oxidation reaction and / or oxidative coupling reaction of alkanes is carried out at a pressure in the range of 0.1 MPa to 10 MPa, preferably 0.1 MPa to 5.0 MPa, or 0.2 MPa to 3.0 MPa.

[0092] In one embodiment, the process comprises the step of preheating the fluidized bed reactor with a gaseous stream before carrying out the partial oxidation reaction and / or oxidative coupling reaction of alkanes in the fluidized bed reactor; preferably, the gaseous stream is a stream of an inert gas and / or has a temperature comprised between 400 °C and 1000 °C. This embodiment is of interest when the particles of the bed, such as silicon carbide, have too high an electrical resistivity at room temperature to initiate the electrical heating of the bed.

[0093] For example, the partial oxidation reaction and / or oxidative coupling reaction of alkanes is carried out in the presence of a dilution stream and at a weight hourly space velocity of the reaction stream comprised between 0.1 h -1 to 100 h -1 preferably comprised between 1.0 h -1 to 50 h -1 The weight hourly space velocity is defined as the ratio of the mass flow rate of the reaction stream to the mass of the solid particulate material in the fluidized bed.

[0094] The feedstock containing light alkanes for the process of the present invention comprises one or more selected from natural gas and / or biogas. The feedstock containing light alkanes for the process of the present invention comprises one or more alkanes selected from methane, ethane, propane, butane, isobutane, and any mixture thereof. The feedstock containing light alkanes further comprises one or more oxidants selected from COS (carbonyl sulfide), CO2 (carbon dioxide), and any mixture thereof. In one embodiment, the step of providing a stream of the feedstock containing light alkanes containing one or more alkanes and one or more oxidants comprises mixing: a stream containing one or more alkanes selected from methane, ethane, propane, butane, isobutane, and any mixture thereof; and a stream containing one or more oxidants selected from COS (carbonyl sulfide), CO2 (carbon dioxide), and any mixture thereof. The mixing can be carried out outside or in situ (i.e., inside the at least one fluidized bed reactor) of the at least one fluidized bed reactor.

[0095] For example, COS can be produced from the acid gas components (H2S and CO2) present in natural gas reservoirs or biogas digesters by techniques known in the art.

[0096] In one embodiment, step a) includes a sub-step of producing a stream containing COS, wherein the sub-step comprises providing a feed stream containing at least 30 wt% carbon dioxide (CO2) and at least 20 wt% hydrogen sulfide (H2S) based on the total weight of the feed stream, and converting the feed stream into a stream containing COS; wherein the conversion is carried out at a temperature in the range of 50 to 800 °C, a pressure in the range of 0.01 to 5 MPa (0.1 to 50 bar), and a GHSV in the range of 0.1 to 10 h -1 range, wherein the stream containing COS contains water and at least 10 wt% carbonyl sulfide (COS) based on the total weight of the stream containing COS; preferably, the sub-step of producing the stream containing COS is carried out in the presence of a COS conversion catalyst and at least one adsorbent.

[0097] For example, in step b), the particles of the bed are fluidized by passing a gaseous stream comprising the feedstock containing light alkanes upward through the bed. For example, in step b), the particles of the bed are fluidized by passing a gaseous stream containing methane upward through the bed. For example, the feedstock containing light alkanes is a methane feedstock.

[0098] In particular, the olefins obtained in the process of the present invention may include one or more olefins selected from ethylene, propylene, butene, isobutene, or any mixture thereof.

[0099] In a preferred embodiment, the residence time of the alkane-containing feedstock in the fluidized bed section of the reactor, where the temperature is from 600 to 1500 °C, can be in the range of 0.01 to 5.0 seconds, preferably 0.1 to 1.0 second.

[0100] For example, the step of heating the fluidized bed is carried out by passing an electric current through the fluidized bed at a voltage of at most 300 V, preferably at most 200 V, more preferably at most 150 V, even more preferably at most 120 V, most preferably at most 100 V, and even most preferably at most 90 V.

[0101] For example, the process includes the step of preheating one or more fluidized bed reactors with a gaseous stream before carrying out the partial oxidation reaction and / or oxidative coupling reaction of the alkane in the fluidized bed reactor; preferably, the gaseous stream is a stream of an inert gas and / or has a temperature comprised between 400 °C and 1000 °C.

[0102] For example, the at least one fluidized bed reactor provided in step a) includes a heating zone and a reaction zone, and the step c) of heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C for carrying out the partial oxidation reaction and / or oxidative coupling reaction of the alkane includes the following sub-steps:

[0103] - Heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C by passing an electric current through the heating zone of at least one fluidized bed,

[0104] - Conveying the heated particles from the heating zone to the reaction zone,

[0105] - In the reaction zone, fluidizing the heated particles by passing a stream comprising a feedstock containing light alkanes and optionally a diluent gas upward through the bed of the reaction zone to obtain a fluidized bed for the conversion of the feedstock containing light alkanes from alkanes to olefins,

[0106] - Optionally, collecting the particles from the reaction zone and recycling them to the heating zone.

[0107] For example, the at least one fluidized bed reactor provided in step a) includes a heating zone and a reaction zone, and the step c) of heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C for carrying out the partial oxidation reaction and / or oxidative coupling reaction of the alkane includes the following sub-steps:

[0108] - Preheating the fluidized bed to a temperature in the range of 400 °C to 1000 °C by passing an upwardly fluidizing stream through the particle bed, the fluidizing stream being a gaseous stream having a temperature in the range of 400 °C to 1000 °C;

[0109] - Heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C by passing an electric current through the heating zone,

[0110] - Transporting the heated particles from the heating zone to the reaction zone,

[0111] - In the reaction zone, fluidizing the heated particles by passing a stream comprising a feedstock containing light alkanes and optionally a diluent gas upward through the bed of the reaction zone to obtain a fluidized bed for the conversion of alkanes to olefins in the feedstock containing light alkanes,

[0112] - Optionally, collecting the particles from the reaction zone and recycling them to the heating zone.

[0113] Thus, preferably, before step c), the particles are preheated and / or heated in a preheating zone and / or in the heating zone such that:

[0114] - The at least one fluidized bed reactor provided in step a) comprises a preheating zone, wherein the preheating step is carried out by passing a gaseous stream upward through the bed, wherein the gaseous stream is supplied to the preheating zone, and wherein the gaseous stream used has a temperature in the range of 400 °C to 1000 °C; and / or

[0115] - The at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone, wherein the particles of the bed are fluidized in the heating zone by passing a gaseous stream having a temperature in the range of 400 °C to 1000 °C upward through the bed, and wherein the fluidized bed is heated to a temperature in the range of 600 °C to 1500 °C by passing an electric current through the heating zone.

[0116] The fluidizing stream may be a gaseous stream comprising one or more diluents (e.g., one or more inert gases).

[0117] Step c) provides for the conversion of alkanes to olefins, such as partial oxidation reactions and / or oxidative coupling reactions of alkanes, and step c) is carried out on a feedstock containing light alkanes, which implies that a feedstock containing light alkanes is provided.

[0118] For example, in step b), the particles of the bed are fluidized by passing a gaseous stream upward through the bed and when the heating zone and the reaction zone are mixed (i.e., the same zone); the gaseous stream (i.e., the fluidizing stream) may be or include a feedstock containing light alkanes.

[0119] For example, in step b), by passing the gaseous stream upward through the bed and fluidizing the particles of the bed when the heating zone and the reaction zone are separate zones, the gaseous stream provided to the heating zone (i.e., the fluidized stream) may not contain a feedstock comprising light alkanes. For example, in step b), by passing the gaseous stream upward through the bed to fluidize the particles of the bed, and the process comprises providing at least one fluidized bed reactor as the heating zone and at least one fluidized bed reactor as the reaction zone, the gaseous stream provided to the heating zone in step b) does not contain a feedstock comprising light alkanes, and the gaseous stream provided to the reaction zone comprises a feedstock comprising light alkanes.

[0120] It should be understood that a feedstock comprising light alkanes is provided to the reaction zone, and when the heating zone is separated from the reaction zone, a feedstock comprising light alkanes is not provided to the heating zone.

[0121] Advantageously, the reaction product comprises one or more olefins and carbon monoxide.

[0122] According to a second aspect, the present disclosure provides an apparatus for carrying out the conversion of alkanes to olefins according to at least one embodiment of the first aspect, characterized in that the apparatus comprises:

[0123] - a CO2 sulfidation unit comprising one or more conversion reactors,

[0124] - an optional separation unit,

[0125] - an energized fluidized bed unit, the energized fluidized bed unit comprising at least one fluidized bed reactor, the fluidized bed reactor comprising: at least two electrodes; a reaction vessel; one or more fluid nozzles for introducing a fluidizing gas and / or a feedstock stream comprising light alkanes into the at least one fluidized bed reactor; and a bed comprising particles; wherein at least 10 wt% of the particles of the bed are conductive based on the total weight of the particles of the bed and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at a temperature of 800 °C;

[0126] And wherein the CO2 sulfidation unit, the separation unit when present, and the energized fluidized bed unit are fluidly connected in series in the order mentioned. This is when the process for converting alkanes to olefins further comprises a sub-step of generating a stream containing COS.

[0127] Preferably, the conversion of alkanes to olefins is or comprises a partial oxidation reaction and / or an oxidative coupling reaction of alkanes comprising light alkanes.

[0128] In one embodiment, the device includes a separation unit and further includes at least a recycle pipeline to recycle the unreacted carbon dioxide and unreacted hydrogen sulfide separated in the separation unit back to the CO2 sulfidation unit.

[0129] For example, the one or more conversion reactors are fixed-bed reactors.

[0130] Advantageously, at least one fluidized-bed reactor has no heating device. For example, at least one fluidized-bed reactor has no heating device located around or inside the reaction vessel. For example, all fluidized-bed reactors have no heating device. When it is stated that at least one of the fluidized-bed reactors has no "heating device", it means "classical" heating devices such as ovens, gas burners, hot plates, etc. Except for at least two electrodes of the fluidized-bed reactor itself, there are no other heating devices. For example, at least one fluidized-bed reactor has no heating device selected from ovens, gas burners, hot plates, or any combination thereof. For example, all fluidized-bed reactors have no heating device selected from ovens, gas burners, hot plates, or any combination thereof.

[0131] In a preferred embodiment, the at least one fluidized-bed reactor including at least two electrodes and a bed containing particles has no structured packing, such as honeycomb monolith or cross plates.

[0132] For example, the fluidizing gas is one or more diluent gases.

[0133] For example, the at least one reaction vessel has an inner diameter of at least 100 cm, preferably at least 200 cm, more preferably at least 300 cm.

[0134] Preferably, the reaction vessel includes a reactor wall made of a corrosion-resistant material, and advantageously, the reactor wall material includes nickel (Ni), SiAlON ceramic, yttria-stabilized zirconia (YSZ), tetragonal polycrystalline zirconia (TZP), and / or tetragonal zirconia polycrystal (TPZ).

[0135] Preferably, one of the electrodes is the reaction vessel or the gas distributor, and / or the at least two electrodes are made of stainless steel material or nickel-chromium alloy or nickel-chromium-iron alloy.

[0136] For example, the at least one fluidized-bed reactor includes a heating zone and a reaction zone, one or more fluid nozzles for supplying a stream of a feed containing light alkanes to the reaction zone, and optional means for transporting the particles of the bed from the reaction zone back to the heating zone.

[0137] For example, the apparatus comprises an energized fluidized bed unit having at least two fluidized bed reactors connected to each other, wherein at least one of the at least two fluidized bed reactors is a heating zone, and at least another of the at least two fluidized bed reactors is a reaction zone. Preferably, the energized fluidized bed unit comprises one or more fluid nozzles arranged to inject a stream of feedstock comprising light alkanes into at least one of the fluidized bed reactors serving as the reaction zone; means for transporting the bed particles from the heating zone to the reaction zone when necessary; and optional means for transporting the particles from the reaction zone back to the heating zone. The significance of this configuration is that a given particle bed is shared for at least two fluidized bed reactors.

[0138] For example, the at least one fluidized bed reactor is a single fluidized bed reactor, wherein the heating zone is the bottom part of the fluidized bed reactor, and the reaction zone is the top part of the fluidized bed reactor. Preferably, the apparatus comprises one or more fluid nozzles for injecting a feedstock comprising light alkanes between the two zones. The diameters of the heating zone and the reaction zone may be different to achieve optimal conditions for heating in the bottom zone and for methane conversion in the top zone. The particles may move from the heating zone to the reaction zone by entrainment, and return from the reaction zone to the heating zone by gravity in the opposite direction. Optionally, the particles may be collected from the upper heating zone and transported back to the bottom heating zone through a separate transport line.

[0139] For example, the at least one fluidized bed comprises at least two lateral zones, the at least two lateral zones being an outer zone and an inner zone, wherein the outer zone surrounds the inner zone, and the outer zone is the heating zone and the inner zone is the reaction zone. In a less preferred configuration, the outer zone is the reaction zone, and the inner zone is the heating zone. Preferably, the apparatus comprises one or more fluid nozzles for injecting a feedstock comprising light alkanes into the reaction zone.

[0140] According to a third aspect, the present disclosure provides the use of a bed comprising particles for the conversion of alkanes to olefins in at least one fluidized bed reactor according to the first aspect, the significance of this use being that, based on the total weight of the particles of the bed, at least 10% by weight of the particles of the bed are conductive and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at a temperature of 800 °C.

[0141] For example, the conductive particles are or comprise one or more selected from the following: one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more carbon-containing particles, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0142] For example, the conductive particles are or comprise one or more selected from the following: one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, graphite, carbon black, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0143] For example, the uses include heating a bed containing particles to a temperature in the range of 600 °C to 1500 °C in a first reactor, transporting the heated particle bed from the first reactor to a second reactor, and providing a feedstock containing light alkanes to the second reactor; preferably, at least the second reactor is a fluidized bed reactor and / or at least the second reactor has no heating device; more preferably, the first reactor and the second reactor are fluidized bed reactors, and / or the first and the second reactors have no heating device. For example, the second reactor has no electrodes.

[0144] According to a fourth aspect, the present disclosure provides the use of an apparatus comprising at least one fluidized bed reactor for carrying out partial oxidation and / or oxidative coupling of alkanes, characterized in that the apparatus is according to the second aspect. Preferably, the use of an apparatus with at least one fluidized bed reactor for carrying out partial oxidation and / or oxidative coupling of alkanes in a process according to the first aspect.

[0145] Specific features, structures, characteristics or embodiments can be combined in any suitable manner in one or more embodiments, as will be apparent to those skilled in the art from the present disclosure. Description of the Drawings

[0146] - Figure 1 Shows an apparatus according to the prior art.

[0147] - Figure 2 Shows an apparatus according to the present disclosure having one reactor, wherein the heating zone and the reaction zone are the same.

[0148] -Figure 3 An apparatus with one reactor according to the present disclosure is shown, where one of the heating zone and the reaction zone is arranged above the other.

[0149] - Figure 4 An apparatus with one reactor according to the present disclosure is shown, where the heating zone and the reaction zone are arranged laterally with respect to each other.

[0150] - Figure 5 An apparatus with two reactors according to the present disclosure is shown. Detailed Description

[0151] For the present disclosure, the following definitions are given:

[0152] As used herein, the terms "comprising" and "comprised of" are synonymous with "including" or "containing", and are inclusive or open-ended, and do not exclude additional unlisted members, elements or method steps. The terms "comprising" and "comprised of" also include the term "consisting of".

[0153] Numeric ranges expressed by endpoints include all integers, and, where appropriate, fractions included within the range (e.g., when referring to, for example, a plurality of elements, 1 to 5 may include 1, 2, 3, 4, 5, and when referring to, for example, measured values, may also include 1.5, 2, 2.75 and 3.80). The expression of endpoints also includes the endpoint values themselves (e.g., 1.0 to 5.0 includes both 1.0 and 5.0). Any numeric range expressed herein is intended to include all sub-ranges included therein.

[0154] The term "transition metal" refers to an element whose atoms have a partially filled d subshell, or which can produce a cation with an incomplete d subshell (IUPAC 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. The metals Ga, In, Sn, Tl, Pb and Bi are considered "post-transition" metals.

[0155] The present disclosure provides a process for the partial oxidation and / or oxidative coupling of light alkanes, the method comprising the following steps:

[0156] a) Provide a stream of a feedstock comprising light alkanes, wherein the stream of the feedstock comprising light alkanes further comprises one or more oxidants selected from carbon dioxide, carbonyl sulfide, and any mixture thereof; and further provide at least one fluidized bed reactor, the fluidized bed reactor comprising at least two electrodes and a bed comprising particles;

[0157] b) Fluidize the particles of the bed, for example, by passing a gaseous stream upward through the bed to obtain a fluidized bed;

[0158] c) Heat the fluidized bed to a temperature in the range of 600 °C to 1500 °C to effect the conversion of the light alkanes in the feedstock to olefins; and

[0159] d) Optionally, recover the product of the reaction,

[0160] The process is notable in that step c) of heating the fluidized bed is carried out by passing an electric current through the fluidized bed; the particles of the bed comprise conductive particles and optionally particles of a catalytic composition; and at least 10 wt% of the particles based on the total weight of the particles of the bed are conductive and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C.

[0161] For example, the conductive particles of the bed are or comprise one or more selected from: one or more carbon-containing particles, one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof.

[0162] For example, the conductive particles of the bed are or comprise one or more selected from: graphite, carbon black, one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof.

[0163] In one embodiment, based on the total weight of the conductive particles of the bed, 50 wt% to 100 wt%; preferably 60 wt% to 100 wt%; more preferably 70 wt% to 100 wt%; even more preferably 80 wt% to 100 wt%, and most preferably 90 wt% to 100 wt% of the conductive particles of the bed are one or more selected from the following: graphite, carbon black, one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0164] For example, in step b), the particles of the bed are fluidized by causing a fluidized upward flow of a gaseous stream that is a feedstock comprising light alkanes to pass through the bed. For example, in step b), the particles of the bed are fluidized by causing a fluidized upward flow of a gaseous stream comprising methane to pass through the bed. For example, the feedstock comprising light alkanes is a methane feedstock. For example, the step of heating the fluidized bed is carried out by passing a current at a voltage of up to 300 V, preferably up to 200 V, more preferably up to 150 V, even more preferably up to 120 V, most preferably up to 100 V, and even most preferably up to 90 V through the fluidized bed.

[0165] The solid particulate material in a fluidized bed reactor is typically supported by a perforated plate, a perforated plate, a plate having nozzles or flues (referred to as a distributor). Then, the fluid is forced to flow upward through the distributor and travel through the voids between the solid particulate material. At lower fluid velocities, the solids remain settled as the fluid passes through the voids in the material, referred to as a packed bed reactor. When the fluid velocity increases, the particulate solids will reach a stage where the force of the fluid on the solids is sufficient to counteract the weight of the solid particulate material. This stage is referred to as incipient fluidization and occurs at this minimum fluidization velocity. Once this minimum velocity is exceeded, the contents of the reactor bed begin to expand and become fluidized. Depending on the operating conditions and the nature of the solid phase, various flow regimes can be observed in such a reactor. The minimum fluidization velocity required to achieve bed expansion depends on the size, shape, porosity, and density of the particles and the density and viscosity of the upward flowing fluid.

[0166] P.R. Gunjal, V.V. Ranade, in Industrial Catalytic Processes for Fine and Specialty Chemicals, (2016) pointed out (recorded, read) that Geldart distinguished four different classes of fluidization based on the average particle, which determined the fluidization flow pattern:

[0167] - Type A, aeratable fluidization (medium-sized and medium-density particles that are relatively easy to fluidize; typically 30 - 100 μm, particles with a density of ~1500 kg / m 3 );

[0168] - Type B, sandy fluidization (heavier particles that are difficult to fluidize; typically 100 - 800 μm, particles with a density of 1500 to 4000 kg / m 3 );

[0169] - Type C, cohesive fluidization (typical fluidization of powdered solid particles; fine-sized particles (~20 μm), where the inter-particle forces or cohesive forces are dominant); and

[0170] - Type D, spoutable fluidization (large density and relatively large particles ~1 - 4 mm, dense and spoutable).

[0171] Fluidization can be generally divided into two flow patterns (Fluid Bed Technology in Materials Processing, 1999, CRC Press): homogeneous fluidization and heterogeneous fluidization. In homogeneous or particulate fluidization, the particles are fluidized uniformly without any obvious voids. In heterogeneous or bubbling fluidization, bubbles without solids can be clearly observed. These voids behave like bubbles in a gas-liquid flow and exchange gas with changing size and shape with the surrounding homogeneous medium while rising in the medium. In particulate fluidization, the bed expands smoothly as a large number of particles move, and the bed surface is well-defined. Particulate fluidization is only observed for Geldart-Type A particles. The bubbling fluidization flow pattern is observed at a much higher velocity than homogeneous fluidization, where distinguishable bubbles growing from the distributor can coalesce with other bubbles and eventually break at the surface of the bed. These bubbles enhance the mixing of the solid and the gas, and the bubble size further increases with the increase in the fluidization velocity. When the bubble diameter increases up to the reactor diameter, the slug flow pattern is observed. In the turbulent flow pattern, the bubbles grow and start to break as the bed expands. Under these conditions, the top surface of the bed is no longer distinguishable. In fast fluidization or pneumatic fluidization, the particles are transported out of the bed and need to be recycled back into the reactor. No obvious bed surface is observed.

[0172] The fluidized bed reactor has the following advantages:

[0173] Uniform particle mixing : Due to the inherent fluid-like behavior of the solid particulate material, the fluidized bed does not experience the poor mixing that occurs in a packed bed. The elimination of radial and axial concentration gradients also allows for better fluid-solid contact, which is crucial for reaction efficiency and quality.

[0174] Uniform temperature gradient : Many chemical reactions require the addition or removal of heat. Local hot or cold spots within the reaction bed are avoided in the case of fluidization.

[0175] Ability to operate the reactor continuously : The fluidized bed nature of these reactors allows for the ability to continuously withdraw products and introduce new reactants into the reaction vessel. On top of the continuous operation of chemical reactions, due to the flowable solid particulate material, the fluidized bed also allows for the continuous withdrawal of solid material either continuously or at a given frequency or the continuous addition of fresh solid material either continuously or at a given frequency.

[0176] Heat can be generated by passing an electric current through a conductive material (resistor body) with a sufficiently high electrical resistivity so that electrical energy is converted into heat. The electrical resistivity (also known as specific resistance or volume resistivity, an inherent property independent of shape and size) and its reciprocal (conductivity) are fundamental material properties that quantify how strongly a material resists or conducts an electric current (the SI unit of electrical resistivity is ohm-meter (Ω·m), and conductivity is siemens per meter (S / m)).

[0177] When an electric current passes through a fixed bed of a solid of conductive particles having sufficient resistivity, the bed provides a resistance to the flow of the current; this resistance depends on many parameters, including the nature of the solid, the nature of the connections between the particles within the bed, the bed porosity, the bed height, the electrode geometry, etc. If the same fixed bed is fluidized via a passing gas, the resistance of the bed increases; the resistance provided by the conductive particles generates heat within the bed and can maintain the bed under isothermal conditions (referred to as an electrothermal fluidized bed or an electrified bed reactor). In many high-temperature reactions, the electrified bed reactor provides in-situ heating during the reaction and is particularly useful for operating endothermic reactions and thus saves energy since no external heating or heat transfer is required. The prerequisite is that at least part of the solid particle material is conductive, but non-conductive solid particles can be mixed and still result in sufficient heat generation. Such non-conductive or very high resistivity solids can play a catalytic role in chemical transformations. The characteristics of the bed material determine the resistance of the electrothermal fluidized bed furnace; since this is a type of heat generation of a charged resistor body, the specific resistance of the particles affects the bed resistance. The size, shape, composition, and size distribution of the particles also affect the magnitude of the bed resistance. Additionally, when the bed is fluidized, the voids generated between the particles increase the bed resistance. The total resistance of the bed is the sum of two components, such as the electrode contact resistance (i.e., the resistance between the electrode and the bed) and the bed resistance. A larger contact resistance will cause a large amount of local heating near the electrode while the rest of the bed remains rather cold. The following factors determine the contact resistance: the current density, the fluidization velocity, the type of bed material, the electrode size, and the type of material used for the electrode. The electrode composition can advantageously be a metal such as iron, cast iron, or other steel alloys, copper or copper-based alloys, nickel or nickel-based alloys, or refractory-like metals, intermetallic compounds, or alloys of Zr, Hf, V, Nb, Ta, Cr, Mo, W, or ceramic-like carbides, nitrides, or carbon-based such as graphite. The contact area between the bed material and the electrode can be adjusted according to the electrode immersion and the amount of particulate material in the fluidized bed. Thus, the resistance and power level can be manipulated by adjusting these variables. Advantageously, to prevent the electrodes from overheating compared to the fluidized bed, the resistivity of the electrodes (and thus the Joule heating) should be lower than that of the particulate material of the fluidized bed. In a preferred embodiment, the electrodes can be cooled by passing a cooler fluid inside or outside the electrodes. Such a fluid can be any liquid that evaporates upon heating, a gas stream, or can be a part of a cooler feedstock that first cools the electrodes before entering the fluidized bed.

[0178] The bed resistance can be predicted by Ohm's law。The current transfer mechanism in a fluidized bed is believed to occur at low operating voltages by the flow of current along a continuous chain of conductive particles. At high voltages, current transfer occurs through a combination of chains of conductive particles, arc discharges between the electrodes and the bed, and arc discharges between particles that can ionize the gas, thereby reducing the bed resistance. In principle, arc discharges within the bed are undesirable because they reduce electrical and thermal efficiency. Gas velocity strongly affects the bed resistance, with the resistance from a settling bed increasing sharply as the gas flow rate increases; a maximum occurs near the initial fluidization velocity, followed by a decrease at higher velocities. At gas flow rates sufficient to initiate slugging, the resistance increases again. Average particle size and shape affect the resistance because they affect the points of contact between particles. Generally speaking, the bed resistivity increases by a factor of 2 to 5 from a settling bed (e.g., 20 Ohm.cm for graphite) to initial fluidization (60 Ohm.cm for graphite), and by a factor of 10 to 40 from a settling bed to twice the initial fluidization velocity (300 Ohm.cm for graphite). Non-conductive or less conductive particles can be added to the conductive particles. If the conductive solid fraction is small, the resistivity of the bed will increase due to breaks in the conductive solid chain between the electrodes. If the non-conductive solid fraction is finer in size, it will fill the gaps or voids between the larger conductive solids and thus increase the bed resistance.

[0179] Generally speaking, for a desired high heating power, a high current at low voltage is preferred. The power source can be AC or DC. The voltage applied in an electrothermal fluidized bed is typically below 100V to achieve sufficient heating power. The electrothermal fluidized bed can be controlled in the following three ways:

[0180] 1. Adjust the gas flow rate: Since the conductivity of the bed depends on the degree of voids or bubbles within the bed, any change in the gas flow rate will change the power level; thus, the temperature can be controlled by adjusting the fluidization gas flow rate. The flow rate required for optimal performance corresponds to a velocity equal to or slightly exceeding the minimum fluidization velocity.

[0181] 2. Adjust the electrode immersion: The power level can also be controlled by changing the level of electrode immersion within the bed, since the conductivity of the bed depends on the contact area between the conductive particles and the electrodes: the surface area of the electrodes available for current increases with electrode immersion, resulting in a decrease in the total resistance.

[0182] 3. Adjust the applied voltage: Although it is often more affordable or economical to change the power level by using the first two methods than by increasing the applied voltage, however, in an electrothermal fluidized bed, all three variables can be used to control the resulting heating power.

[0183] The walls of the reactor are generally made of graphite, ceramics (such as SiC), high melting point metals or alloys, as it is versatile and compatible with many high temperature reactions of industrial interest. Since an oxidizing atmosphere can cause carbon materials to burn or produce a non-conductive metal oxide layer on top of metals or alloys, the atmosphere used for the reaction is often limited to neutral or reducing types. The wall and / or the distribution plate itself can act as an electrode of the reactor. The fluidized solid can be graphite or any other high melting point conductive particles. Other electrodes usually immersed in the bed can also be graphite or high melting point metals, intermetallic compounds or alloys.

[0184] It can be advantageous to generate the required reaction heat by heating the conductive particles and / or the catalyst particles in a separate zone of the reactor where there is little or essentially no feed hydrocarbon but only diluent gas. The benefit is that the appropriate fluidization conditions for generating heat by passing an electric current through a bed of conductive particles can be optimized, while the optimal reaction conditions during hydrocarbon conversion can be selected for other zones of the reactor. Such conditions of optimal void fraction and linear velocity may be different for heating purposes and chemical conversion purposes.

[0185] In one embodiment of the present disclosure, the apparatus comprises two zones arranged in series, i.e., the first zone is a heating zone and the second zone is a reaction zone, wherein the conductive particles and the catalyst particles continuously move or are transported from the first zone to the second zone and vice versa. The first and the second zones can be different parts of a fluidized bed or can be located in separate fluidized bed reactors connected to each other.

[0186] In the said embodiment, the process for the conversion of alkanes to alkenes comprises the following steps:

[0187] a) Providing a stream of feed comprising light alkanes, the stream of feed comprising light alkanes comprising one or more alkanes and one or more oxidants selected from carbon dioxide, carbonyl sulfide, and any mixture thereof; and further providing at least one fluidized bed reactor comprising at least two electrodes and a bed comprising particles;

[0188] b) Fluidizing the particles to obtain a fluidized bed;

[0189] c) Heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C to carry out partial oxidation and / or oxidative coupling reaction of the alkane moiety of the feed comprising light alkanes; and

[0190] d) Optionally collecting the product of the reaction;

[0191] Step c) of heating the fluidized bed is carried out by passing an electric current through the fluidized bed; wherein the particles of the bed comprise conductive particles and optionally particles of a catalytic composition; and wherein at least 10% by weight of the particles, based on the total weight of the particles of the bed, are conductive particles having a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C;

[0192] Wherein at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone, and wherein step c) of heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C for the conversion of a feedstock comprising light alkanes to olefins comprises the following sub-steps:

[0193] - Heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C by passing an electric current through the heating zone of the at least one fluidized bed,

[0194] - Transporting the heated particles from the heating zone to the reaction zone,

[0195] - In the reaction zone, fluidizing the heated particles by passing a stream comprising the feedstock comprising light alkanes and optionally a diluent gas upward through the bed of the reaction zone to obtain a fluidized bed, and carrying out an endothermic partial oxidation reaction and / or oxidative coupling reaction on the feedstock comprising light alkanes,

[0196] - Optionally, collecting the particles from the reaction zone and recycling them to the heating zone.

[0197] For example, the conductive particles are or comprise one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more carbon-containing particles, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and / or any mixture thereof.

[0198] For example, the conductive particles are or comprise one or more selected from the following: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, graphite, carbon black, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and / or any mixture thereof.

[0199] For example, the stream of the light alkane feedstock has no diluent.

[0200] For example, the flow of the light alkane feedstock is enriched with one or more oxidants by in-situ mixing in the reaction zone.

[0201] For example, the at least one fluidized bed reactor is at least two fluidized bed reactors connected to each other, wherein at least one of the at least two fluidized bed reactors is a heating zone, and at least another of the at least two fluidized bed reactors is a reaction zone. Preferably, at least one fluidized bed reactor serving as the heating zone includes a gravity or pneumatic conveying device to convey particles from the heating zone to the reaction zone, and / or the apparatus includes a device arranged to inject a feedstock containing light alkanes into at least one fluidized bed reactor serving as the reaction zone. The apparatus does not have a device for injecting a feedstock containing light alkanes into at least one fluidized bed reactor serving as the heating zone.

[0202] For example, the at least one fluidized bed reactor is a single fluidized bed reactor, wherein the heating zone is the bottom part of the fluidized bed reactor, and the reaction zone is the top part of the fluidized bed reactor. Preferably, the apparatus includes a device for injecting a feedstock containing light alkanes and / or a diluent between the two zones. The diameters of the heating zone and the reaction zone can be different to achieve optimal conditions for heating in the bottom zone and for hydrocarbon conversion in the top zone. The particles can move from the heating zone to the reaction zone by entrainment, and return from the reaction zone to the heating zone by gravity in the opposite direction. Optionally, the particles can be collected from the upper heating zone and conveyed back to the bottom heating zone through a separate conveying pipeline.

[0203] It should be understood that a feedstock containing light alkanes is provided to the reaction zone, and when the heating zone is separated from the reaction zone, preferably no feedstock containing light alkanes is provided to the heating zone. When the heating zone and the reaction zone are mixed (i.e., the same zone); the stream provided in step b) includes a feedstock containing light alkanes.

[0204] In one embodiment, step a) includes a sub-step of generating a stream containing COS, wherein the sub-step includes providing a feed stream containing at least 30 wt% carbon dioxide (CO2) and at least 20 wt% hydrogen sulfide (H2S) based on the total weight of the feed stream, and converting the feed stream into a stream containing COS; wherein the conversion is carried out at a temperature in the range of 50 to 800 °C, at a pressure in the range of 0.01 to 5 MPa (0.1 to 50 bar), and at a GHSV in the range of 0.1 to 10 h -1 The conversion can be described by the following chemical equation:

[0205] The conversion can be described by the following chemical equation:

[0206] CO2 + H2S → COS + H2O

[0207] The reaction will be carried out by reacting gaseous carbon dioxide and gaseous hydrogen sulfide together at a temperature in the range of 50 to 800 °C, at a pressure in the range of 0.1 to 5 MPa (1 to 50 bar), and at a GHSV in the range of 0.1 to 10 h -1 range.

[0208] The conversion reaction produces water. It is preferred to remove the water to avoid hydrolysis of COS to CO2 and H2S. Removing the water also helps to drive the reaction equilibrium to produce more carbonyl sulfide. The water can be removed in a separate sub-step, for example, by drying with an adsorbent. The adsorbent can also be used to at least partially separate the water during the sub-step of producing the stream containing COS. The adsorbent used in the sub-step of producing the stream containing COS and in the sub-step of drying the stream containing COS can be the same or different.

[0209] In one embodiment, the sub-step of producing the stream containing COS is carried out in a separate conversion reactor, preferably containing an adsorbent.

[0210] Any suitable adsorbent capable of absorbing water can be used. Silica, silica gel, or molecular sieves such as 13X or any mixture thereof can be used, for example, to dry the feed stream. Once saturated, the adsorbent can be regenerated by any method known in the art. For example, the adsorbent can be taken offline, and the pressure and / or temperature can be changed to desorb the water and regenerate the adsorbent. A drying gas such as N2 can also be used to desorb the water from the adsorbent. In one embodiment, two or more series of conversion reactors are used as swing beds. In this case, one adsorbent bed (the first bed) is used in the conversion reactor until it is saturated, at which time it is replaced with another adsorbent bed (the second bed) in the conversion reactor while drying the first bed to remove the water. In another embodiment, the adsorbent can be removed and sent to a regenerator for drying and then recycled for reuse.

[0211] In one embodiment, the sub-step of producing the stream containing COS is carried out in the presence of a COS conversion catalyst.

[0212] In a preferred embodiment, the sub-step of generating the stream containing COS is preferably carried out in a fixed bed conversion reactor using a sulfide catalyst, which is preferably a catalyst comprising at least one metal of Group VI, B (e.g., Mo, W) combined with a promoter of at least one metal selected from Group VIII and / or VIIIB (e.g., Ni and / or Co, and / or mixtures thereof), and these metals are used in sulfided form and are preferably supported on alumina, titania, zirconia, silica, carbon, and / or mixtures thereof.

[0213] In a preferred embodiment, the COS conversion catalyst is a mixed metal sulfide and a transition metal sulfide, especially a silica-supported metal sulfide. Other suitable catalysts include silica, amorphous silica-alumina (ASA, commercially available from CRI), and zeolite catalysts such as ZSM-5 (commercially available from Zeolyst International). When the catalyst is a sulfur-based catalyst, it is preferably based on metal oxides selected from Group VI-B (Mo, W, etc.) and Group VIII-B (Co, Ni, Pt, Pd, Ru, Rh, etc.) metals supported on carriers selected from alumina, silica / alumina, zeolite, ferrierite, phosphorylated alumina, phosphorylated silica / alumina, etc. Preferably, the COS conversion catalyst used is NiMo, CoMo, NiW, PtPd, or a mixture of two or more of these. The COS conversion catalyst used can also be based on metals in bulk form, such as the commercially known Nebula-type catalyst. The COS conversion catalyst can also be based on metal oxides selected from Group VI-B (Mo, W, etc.) and Group VIII-B (Co, Ni, Pt, Pd, Ru, Rh, etc.) metals supported on carriers selected from alumina, silica / alumina, zeolite, ferrierite, phosphorylated alumina, phosphorylated silica / alumina, etc., preferably NiMo, CoMo, NiW, PtPd, or a mixture of two or more of these.

[0214] Even more preferably, the COS conversion catalyst is based on nickel oxide on an acidic support such as amorphous silica-alumina, zeolite, ferrierite, phosphorylated alumina, phosphorylated silica / alumina, etc.

[0215] The COS conversion catalyst can be used alone or can be mixed with an adsorbent, which is preferably selected from silica, silica gel, or molecular sieves such as 13X, or any mixture thereof. In a more preferred embodiment, the COS conversion catalyst exhibits an adsorption function. For example, the active phase of the COS conversion catalyst can be deposited on a support capable of absorbing water. Non-limiting examples of possible supports for the COS conversion catalyst include silica, silica gel, or molecular sieves such as 13X, or any mixture thereof.

[0216] In a preferred embodiment, the stream containing COS contains at least 15% by weight of carbonyl sulfide (COS), based on the total weight of the stream containing COS; preferably at least 20% by weight of carbonyl sulfide (COS) up to 80% by weight, preferably up to 75% by weight. To increase the content of COS in the stream containing COS, a person skilled in the art can add a sub-step of separating water and preferably unreacted carbon dioxide (CO2) and unreacted hydrogen sulfide (H2S) (if any) from the stream containing COS. In a preferred embodiment, the unreacted carbon dioxide (CO2) and unreacted hydrogen sulfide (H2S) collected are recycled at the inlet of the conversion reactor.

[0217] In a preferred embodiment, the feed stream is selected to contain at least 20% by weight of carbon dioxide (CO2), based on the total weight of the feed stream.

[0218] In a preferred embodiment, the feed stream is selected to contain at least 20% by weight of hydrogen sulfide (H2S), based on the total weight of the feed stream.

[0219] In a preferred embodiment, the feed stream is selected to contain at most 10% by weight of water, more preferably at most 5% by weight of water, even more preferably at most 1% by weight of water, and in the most preferred embodiment, the feed stream does not contain water. When the feed stream contains water, it is preferably removed by means of an adsorbent.

[0220] Bed containing particles

[0221] To achieve the required temperature for carrying out the partial oxidation reaction and / or oxidative coupling reaction of alkanes, at least 10% by weight of the particles, based on the total weight of the particles of the bed, are conductive and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C.

[0222] For example, the conductive particles of the bed are or comprise one or more selected from the following: one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more carbon-containing particles, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof.

[0223] For example, the conductive particles of the bed are or comprise one or more selected from the following: one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, graphite, carbon black, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof.

[0224] For example, based on the total weight of the conductive particles of the bed, 50 wt% to 100 wt%; preferably, 60 wt% to 100 wt%; more preferably 70 wt% to 100 wt%; even more preferably 80 wt% to 100 wt%, and most preferably 90 wt% to 100 wt% of the conductive particles of the bed are one or more selected from the following: graphite, carbon black, one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof.

[0225] In one embodiment, based on the total weight of the conductive particles of the bed, 50 wt% to 100 wt%; preferably, 60 wt% to 95 wt%; more preferably 70 wt% to 90 wt%; and even more preferably 75 wt% to 85 wt% of the conductive particles of the bed do not contain graphite and / or carbon black.

[0226] For example, based on the total weight of the particles of the bed, the content of the conductive particles is in the range of 10 wt% to 100 wt%; preferably, 15 wt% to 95 wt%, more preferably 20 wt% to 90 wt%, even more preferably 25 wt% to 80 wt%, and most preferably 30 wt% to 75 wt%.

[0227] For example, based on the total weight of the particles in the bed, the content of the conductive particles based on the total weight of the bed is at least 12% by weight; preferably at least 15% by weight, more preferably at least 20% by weight; even more preferably at least 25% by weight, and most preferably at least 30% by weight or at least 40% by weight or at least 50% by weight or at least 60% by weight.

[0228] For example, the conductive particles have a resistivity in the range of 0.005 to 400 Ohm.cm at 800 °C, preferably in the range of 0.01 to 300 Ohm.cm at 800 °C; more preferably in the range of 0.05 to 150 Ohm.cm at 800 °C, and most preferably in the range of 0.1 to 100 Ohm.cm at 800 °C.

[0229] For example, the conductive particles have a resistivity of at least 0.005 Ohm.cm at 800 °C; preferably at least 0.01 Ohm.cm at 800 °C, more preferably at least 0.05 Ohm.cm at 800 °C; even more preferably at least 0.1 Ohm.cm at 800 °C, and most preferably at least 0.5 Ohm.cm at 800 °C.

[0230] For example, the conductive particles have a resistivity of at most 400 Ohm.cm at 800 °C; preferably at most 300 Ohm.cm at 800 °C, more preferably at most 200 Ohm.cm at 800 °C; even more preferably at most 150 Ohm.cm at 800 °C, and most preferably at most 100 Ohm.cm at 800 °C.

[0231] For example, when measured by sieving according to ASTM D4513-11, the particles of the bed have an average particle size in the range of up to 300 μm, preferably in the range of 10 to 200 μm, and more preferably in the range of 30 to 150 μm.

[0232] For example, when measured by sieving according to ASTM D4513-11, the conductive particles of the bed have an average particle size in the range of 5 to 300 μm, preferably in the range of 10 to 200 μm, and more preferably in the range of 30 to 150 μm.

[0233] The resistance is measured using an ohmmeter by the four-probe DC method. The densified powder sample is formed into a cylindrical pellet and placed between the probe electrodes. The resistivity is determined from the measured resistance value R by applying the known expression r = R×A / L, where L is the distance between the probe electrodes (typically a few millimeters), and A is the electrode area.

[0234] The conductive particles of the bed may exhibit electronic, ionic, or mixed electron-ion conductivity. The ionic bonding of many refractory compounds permits ionic diffusion and, accordingly, ionic conduction under the influence of an electric field and appropriate temperature conditions.

[0235] The conductivity s (the proportionality constant between the current density j and the electric field E) is given by

[0236] s = j / E = ∑c i ×Z i q×m i

[0237] where c i is the carrier density (number / cm 3 ), μ i is the mobility (cm 2 / Vs), and Z i q is the charge of the i-th charge carrier (q = 1.6×10 -19 C). The many orders of magnitude difference in s between metals, semiconductors, and insulators is generally caused by differences in c rather than μ. On the other hand, the relatively high conductivity of electronic conductors compared to ionic conductors is generally due to the much higher mobility of electronic species compared to ionic species.

[0238] The most common materials used for resistive heating are subdivided into nine groups:

[0239] (1) Metal alloys, up to a temperature of 1200 - 1400 °C,

[0240] (2) Non-metallic resistors such as silicon carbide (SiC), molybdenum disilicide (MoSi2), nickel silicide (NiSi), sodium silicide (Na2Si), magnesium silicide (Mg2Si), platinum silicide (PtSi), titanium silicide (TiSi2), and tungsten silicide (WSi2), up to 1600 - 1900 °C,

[0241] (3) Various mixed oxides and / or mixed sulfides doped with one or more low-valence cations, with variable temperature optima,

[0242] (4) Graphite, up to 2000 °C,

[0243] (5) Metal carbides,

[0244] (6) Transition metal nitrides,

[0245] (7) Metal phosphides,

[0246] (8) Superionic conductors, and

[0247] (9) Phosphate electrolytes.

[0248] For temperatures up to 1150 - 1250 °C, the first group of metallic alloys can consist of Ni - Cr alloys with a low Fe content (0.5 - 2.0%), preferably alloys Ni - Cr (80% Ni, 20% Cr) and (70% Ni, 30% Cr). Increasing the Cr content increases the oxidation resistance of the material at high temperatures. The second group of metallic alloys with three components is the Fe - Ni - Cr alloy, whose maximum operating temperature in an oxidizing atmosphere is 1050 - 1150 °C, but it can be conveniently used in a reducing atmosphere, or Fe - Cr - Al (chemical composition 15 - 30% Cr, 2 - 6% Al and the balance Fe) that is protected against corrosion by a surface layer of oxides of Cr and Al, can be used up to 1300 - 1400 °C in an oxidizing atmosphere. Silicon carbide, as a non - metallic resistor, can exhibit a wide range of resistivity values, which can be controlled by the way they are synthesized and by the presence of impurities (such as aluminum, iron, oxides, nitrogen, or additional carbon or silicon) that result in non - stoichiometric silicon carbide. Generally speaking, silicon carbide has a high resistivity at low temperatures, but has good resistivity in the range of 500 to 1200 °C. In an alternative embodiment, the non - metallic resistor can be free of silicon carbide and / or can contain molybdenum disilicide (MoSi2), nickel silicide (NiSi), sodium silicide (Na2Si), magnesium silicide (Mg2Si), platinum silicide (PtSi), titanium silicide (TiSi2), tungsten silicide (WSi2), or a mixture thereof.

[0249] Graphite has a rather low resistivity value, with a negative temperature coefficient up to about 600 °C, after which the resistivity starts to increase.

[0250] Many mixed oxides and / or mixed sulfides doped with one or more low - valence cations, which generally have too high a resistivity at low temperatures, become ionic conductors or mixed conductors at high temperatures. The following conditions can make the oxides or sulfides conductors sufficient for heating purposes: Ionic conduction in solids is described in terms of the generation and movement of atomic defects (especially vacancies and interstitials), whose generation and migration are very positively temperature - dependent. Such mixed oxides or sulfides are ionic or mixed conductors, i.e., doped with one or more low - valence cations. Three mechanisms for forming ionic defects in oxides are known: (1) thermally induced intrinsic ionic disorder (e.g., resulting in non - stoichiometric Schottky and Frenkel defect pairs), (2) redox - induced defects, and (3) impurity - induced defects. The first two categories of defects are predicted by statistical thermodynamics, and the latter form satisfies charge neutrality. In the latter case, a high charge - carrier density can be induced by substituting host cations with low - valence cations. Mixed oxides and / or mixed sulfides with a fluorite, pyrochlore, or perovskite structure are very suitable for substitution by one or more low - valence cations.

[0251] A variety of sublattice disordered oxides or sulfides have high ionic transport capabilities at elevated temperatures. These are superionic conductors, such as LiAlSiO4, Li 10 GeP2S 12 , L i3.6 Si 0.6 P 0.4 O4, having the general formula Na 1+x Zr2P 3-x Si x O 12 (where 0 < x < 3) of NaSICON (sodium (Na) superionic conductor) such as Na3Zr2PSi2O 12 (x = 2), or sodium beta-alumina such as NaAl 11 O 17 , Na 1.6 Al 11 0 17.3 , and / or Na 1.76 Li 0.38 Al 10.62 0 17 .

[0252] A high concentration of ionic carriers can be induced in an inherently insulating solid and produce a highly defective solid. Thus, the conductive particles of the bed are or comprise one or more mixed oxides as ionic or mixed conductors (i.e., doped with one or more low-valent cations), and / or one or more mixed sulfides as ionic or mixed conductors (i.e., doped with one or more low-valent cations). Preferably, the mixed oxides are selected from one or more oxides having a cubic fluorite structure, the cubic fluorite structure being at least partially replaced by one or more low-valent cations preferably selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and / or one or more ABO3 perovskites having A and B trivalent cations, at least partially replaced at the A-site by one or more low-valent cations preferably selected from Ca, Sr, or Mg, and containing at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe, and / or mixtures thereof at the B-site; and / or one or more ABO3 perovskites having A divalent cations and B tetravalent cations, at least partially replaced at the B-site by one or more low-valent cations preferably selected from Mg, Sc, Y, Nd or Yb or replaced at the B-site by a mixture of different B elements; and / or one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, at least partially replaced at the A-site by one or more low-valent cations preferably selected from Ca or Mg, and containing at least one of Sn, Zr and Ti at the B-site.

[0253] Preferably, the one or more mixed sulfides are selected from one or more sulfides having a cubic fluorite structure, the cubic fluorite structure being at least partially substituted by one or more lower-valent cations preferably selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and / or one or more ABS3 structures having A and B trivalent cations, at least partially substituted at the A-site by one or more lower-valent cations preferably selected from Ca, Sr, or Mg, and containing at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe, and / or mixtures thereof at the B-site; and / or one or more ABS3 structures having A divalent cations and B tetravalent cations, at least partially substituted at the B-site by one or more lower-valent cations preferably selected from Mg, Sc, Y, Nd or Yb or by a mixture of different B elements at the B-site; and / or one or more A2B2S7 structures having A trivalent cations and B tetravalent cations, at least partially substituted at the A-site by one or more lower-valent cations preferably selected from Ca or Mg, and containing at least one of Sn, Zr and Ti at the B-site.

[0254] Preferably, based on the total number of atoms present in the one or more oxides or sulfides having a cubic fluorite structure, the one or more ABO3 perovskites having A and B trivalent cations, the one or more ABO3 perovskites having A divalent cations and B tetravalent cations, or the one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, respectively, the degree of substitution in the one or more mixed oxides doped with one or more lower-valent cations and having a cubic fluorite structure is 1 to 15 atomic %, preferably 3 to 12 atomic %, more preferably 5 to 10 atomic %.

[0255] Preferably, based on the total number of atoms present in the one or more ABO3 perovskites having A and B trivalent cations, the one or more ABO3 perovskites having A divalent cations and B tetravalent cations, or the one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, respectively, the degree of substitution in the one or more mixed oxides doped with one or more lower-valent cations is 1 to 50 atomic %, preferably 3 to 20 atomic %, more preferably 5 to 15 atomic %.

[0256] Preferably, based on the total number of atoms present in one or more of the ABS3 structures having A and B trivalent cations, one or more of the ABS3 structures having A divalent cations and B tetravalent cations, or one or more of the A2B2S7 structures having A trivalent cations and B tetravalent cations, respectively, the substitution degree in one or more mixed sulfides doped with one or more low-valent cations and having a cubic fluorite structure is 1 to 15 atomic %, preferably 3 to 12 atomic %, more preferably 5 to 10 atomic %.

[0257] Preferably, based on the total number of atoms present in one or more of the ABS3 structures having A and B trivalent cations, one or more of the ABS3 structures having A divalent cations and B tetravalent cations, or one or more of the A2B2S7 structures having A trivalent cations and B tetravalent cations, respectively, the substitution degree in one or more mixed sulfides doped with one or more low-valent cations is 1 to 50 atomic %, preferably 3 to 20 atomic %, more preferably 5 to 15 atomic %.

[0258] One or more oxides having a cubic fluorite structure, one or more ABO3 perovskites having A and B trivalent cations, one or more ABO3 perovskites having A divalent cations and B tetravalent cations, or one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, at least partially substituted by low-valent cations, one or more sulfides having a cubic fluorite structure, one or more ABS3 structures having A and B trivalent cations, one or more ABS3 structures having A divalent cations and B tetravalent cations, one or more A2B2S7 structures having A trivalent cations and B tetravalent cations, at least partially substituted by low-valent cations also mean that the same element (i.e., the high-valent cation) can be reduced to a lower-valent equivalent, for example, Ti(IV) can be reduced to Ti(III), and / or Co(III) can be reduced to Co(II), and / or Fe(III) can be reduced to Fe(II), and / or Cu(II) can be reduced to Cu(I).

[0259] Phosphate electrolytes such as LiPO4 or LaPO4 can also be used as conductive particles.

[0260] Metal carbides, transition metal nitrides, and metal phosphides can also be selected as the conductive particles. For example, the metal carbide is selected from iron carbide (Fe3C), molybdenum carbide (e.g., a mixture of MoC and Mo2C). For example, the one or more transition metal nitrides are selected from zirconium nitride (ZrN), tungsten nitride (e.g., a mixture of W2N, WN, and WN2), vanadium nitride (VN), tantalum nitride (TaN), and / or niobium nitride (NbN). For example, the one or more metal phosphides are selected from copper phosphide (Cu3P), indium phosphide (InP), gallium phosphide (GaP), sodium phosphide (Na3P), aluminum phosphide (AlP), zinc phosphide (Zn3P2), and / or calcium phosphide (Ca3P2).

[0261] In a preferred embodiment of the present disclosure, conductive particles that exhibit a sufficiently low resistivity only at high temperatures can be heated by an external device and then resistively heated to a sufficiently high temperature using electrical overload, or can be mixed with a solid that has a sufficiently low resistivity at low temperatures such that the resulting resistivity of the mixture allows the fluidized bed to be heated to the desired reaction temperature.

[0262] For example, the conductive particles of the bed are or comprise silicon carbide. For example, based on the total weight of the conductive particles of the bed, at least 10 wt% of the conductive particles are silicon carbide particles and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C.

[0263] In embodiments where the conductive particles of the bed are or comprise silicon carbide, those skilled in the art will have the advantage of preheating the fluidized bed reactor with a gaseous stream before performing one or more reactions in the fluidized bed reactor. Advantageously, the gaseous stream is a stream of an inert gas, i.e., nitrogen, argon, helium, methane, carbon dioxide, hydrogen, or steam. The temperature of the gaseous stream can be at least 500 °C, or at least 550 °C, or at least 600 °C, or at least 650 °C, or at least 700 °C, or at least 750 °C, or at least 800 °C, or at least 850 °C, or at least 900 °C. Advantageously, the temperature of the gaseous stream can be comprised between 500 °C and 900 °C, such as between 600 °C and 800 °C or between 650 °C and 750 °C. The gaseous stream of the inert gas can also be used as the fluidizing gas. The preheating of the gaseous stream of the inert gas is carried out by conventional means, including using electrical energy. The temperature of the gaseous stream used to preheat the bed does not need to reach the reaction temperature.

[0264] In fact, silicon carbide has a relatively high resistivity at ambient temperature, and in order to facilitate the start of the reaction, it may be useful to heat the fluidized bed by an external device because preferably the fluidized bed reactor does not have a heating device. Once the bed is heated to the desired temperature, a hot gaseous stream does not have to be used.

[0265] However, in one embodiment, the conductive particles of the bed are or comprise a mixture of silicon carbide particles and conductive particles different from silicon carbide particles.

[0266] A preheating step can also be used in the case where there are conductive particles different from silicon carbide particles in the bed. For example, it can be used when the content of silicon carbide in the conductive particles of the bed is greater than 80% by weight, such as greater than 85% by weight, such as greater than 90% by weight, such as greater than 95% by weight, such as greater than 98% by weight, such as greater than 99% by weight based on the total weight of the particles of the bed. However, the preheating step can be used regardless of the content of silicon carbide particles in the bed.

[0267] In an embodiment where the conductive particles of the bed are or comprise a mixture of silicon carbide particles and conductive particles different from silicon carbide particles, the conductive particles of the bed can comprise 10% to 99% by weight based on the total weight of the conductive particles of the bed; preferably, 15% to 95% by weight, more preferably 20% to 90% by weight, even more preferably 25% to 80% by weight, and most preferably 30% to 75% by weight of silicon carbide particles.

[0268] For example, the conductive particles of the bed are or comprise a mixture of silicon carbide particles and conductive particles different from silicon carbide particles, and the conductive particles of the bed comprise at least 40% by weight based on the total weight of the conductive particles of the bed; preferably at least 50% by weight, more preferably at least 60% by weight, even more preferably at least 70% by weight, and most preferably at least 80% by weight of silicon carbide particles.

[0269] In one embodiment, the conductive particles of the bed can comprise 10% to 90% by weight based on the total weight of the conductive particles of the bed; preferably, 15% to 95% by weight, more preferably 20% to 90% by weight, even more preferably 25% to 80% by weight, and most preferably 30% to 75% by weight of conductive particles different from silicon carbide particles.

[0270] However, it may be interesting to keep the content of the electrically conductive particles different from the silicon carbide particles in the mixture rather low. Thus, in one embodiment, the electrically conductive particles of the bed are or comprise a mixture of silicon carbide particles and electrically conductive particles different from silicon carbide particles, and the electrically conductive particles of the bed comprise from 1 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 3 wt% to 10 wt%, and even more preferably from 4 wt% to 8 wt% of electrically conductive particles different from silicon carbide, based on the total weight of the electrically conductive particles of the bed.

[0271] For example, the electrically conductive particles of the bed are or comprise a mixture of silicon carbide particles and particles different from silicon carbide particles, and the particles different from silicon carbide particles are or comprise graphite particles.

[0272] Thus, in one embodiment, the electrically conductive particles are a combination of silicon carbide particles and graphite particles. Such electrically conductive particles will heat up when the fluidized bed reactor is energized and, due to their fluidization, contribute to raising and / or maintaining the temperature inside the reactor. The Joule heating of graphite allows the heating of the reactants and / or other particles present inside the fluidized bed reactor to be accelerated.

[0273] For example, the graphite can be flake graphite. Also preferably, when determined by sieving according to ASTM D4513-11, the graphite has an average particle size in the range of 1 to 400 μm, preferably 5 to 300 μm, more preferably 10 to 200 μm, and most preferably 30 to 150 μm.

[0274] The presence of graphite particles in the bed allows the process according to the present disclosure to be applied with or without a preheating step, preferably without a preheating step. In fact, the graphite particles heat up when the fluidized bed reactor is energized and, due to their fluidization, contribute to raising and / or maintaining the desired temperature inside the reactor.

[0275] Silicon carbide particles

[0276] For example, the silicon carbide is selected from sintered silicon carbide, nitride-bonded silicon carbide, recrystallized silicon carbide, reaction-bonded silicon carbide, and any mixture thereof.

[0277] Sintered SiC (SSiC) is a self-bonded material containing less than 1 wt% of sintering aids (typically boron).

[0278] Recrystallized silicon carbide (RSiC), a high-purity SiC material sintered by an evaporation-condensation process, without any additives.

[0279] Nitride-bonded silicon carbide (NBSC) is prepared by adding fine silicon powder with silicon carbide particles or finally sintering in the presence of mineral additives in a nitriding furnace. The silicon carbide is bonded by the silicon nitride phase (Si3N4) formed during nitriding.

[0280] Reaction-bonded silicon carbide (RBSC) (also known as silicided silicon carbide or SiSiC) is a type of silicon carbide manufactured by the chemical reaction between porous carbon or graphite and molten silicon. Silicon reacts with carbon to form silicon carbide and bond the silicon carbide particles. Any excess silicon fills the remaining pores in the body and produces a dense SiC-Si composite. Due to the residual traces of silicon, reaction-bonded silicon carbide is often referred to as silicided silicon carbide. This process is variously called reaction bonding, reaction sintering, self-bonding, or melt infiltration.

[0281] Generally, high-purity SiC particles have a resistivity above 1000 Ohm.cm, while sintered, reaction-bonded, and nitride-bonded ones can exhibit a resistivity of about 100 to 1000, depending on the impurities in the SiC phase. Depending on the sintering additives and heat treatment conditions, bulk polycrystalline SiC ceramics show a wide range of resistivity (Journal of the European Ceramic Society, Vol. 35, No. 15, December 2015, p. 4137; Ceramics International, Vol. 46, No. 4, March 2020, p. 5454). High-purity SiC polytypes have a high resistivity (>10 6 Ω.cm) due to their large bandgap energy. However, the resistivity of SiC is affected by doped impurities. N and P act as n-type dopants and decrease the resistivity of SiC, while Al, B, Ga, and Sc act as p-type dopants. SiC doped with Be, O, and V is highly insulating. N is considered the most effective dopant for improving the conductivity of SiC. For N doping of SiC (for reducing resistivity), Y2O3 and Y2O3-REM2O3 (REM, rare earth metal = Sm, Gd, Lu) have been used as sintering additives for the effective growth of conductive SiC grains containing N donors. N doping in SiC grains is promoted by adding nitrides (AlN, BN, Si3N4, TiN, and ZrN) or a combination of nitrides and Re2O3 (AlN-REM2O3 (REM = Sc, Nd, Eu, Gd, Ho, and Er) or TiN-Y2O3).

[0282] Reactions for converting alkanes to alkenes such as partial oxidation reactions and / or oxidative coupling reactions of light alkanes

[0283] Embodiments of the present invention relate to a process for converting alkanes, the process comprising contacting a reforming feed or combined feed comprising at least one alkane, and at least one oxidizing agent, and optionally at least one diluent, under suitable reaction conditions. The one or more alkanes are or comprise methane.

[0284] The feedstock containing light alkanes may contain one or more alkanes, which are methane and one or more selected from ethane (C2H6), propane (C3H8), butane (C4H 10 ) and its structural isomers (e.g., n-butane and / or isobutane), pentane (C5H 12 ) and its structural isomers, higher molecular weight alkanes (C6+ alkanes), and any mixture thereof.

[0285] The feedstock containing light alkanes may further contain one or more hydrocarbons selected from ethylene (C2H4), propylene (C3H6), butene (C4H8) and its structural and positional isomers (e.g., 1-butene, 2-butene, and / or isobutene), pentene (C5H 10 ) and its structural and positional isomers, higher molecular weight hydrocarbons (C6+ hydrocarbons), and any mixture thereof.

[0286] In one embodiment, the feedstock containing light alkanes having one or more alkanes and one or more oxidizing agents is obtained by mixing: a stream containing one or more alkanes selected from methane, ethane, propane, butane, isobutane, and any mixture thereof; and a stream containing one or more oxidizing agents selected from COS (carbonyl sulfide), CO2 (carbon dioxide), and any mixture thereof. The mixing can be carried out outside or in situ (i.e., inside the at least one fluidized bed reactor) of the at least one fluidized bed reactor.

[0287] Preferably, the alkane content in the feedstock containing light alkanes suitable for the conversion of alkanes to olefins is at least 5% by volume, more preferably at least 15% by volume, based on the total volume of the feedstock containing light alkanes. For example, the alkane content is at most 95% by volume based on the total volume of the feedstock containing light alkanes.

[0288] For example, the content of methane in the feedstock containing light alkanes is at least 5% by volume, more preferably at least 15% by volume, based on the total volume of the feedstock containing light alkanes. For example, the methane content is at most 95% by volume based on the total volume of the feedstock containing light alkanes.

[0289] The content of the oxidant, which can be CO2, COS, or a mixture thereof, is at least 5% by volume, more preferably at least 15% by volume, of the total volume of the feedstock containing light alkanes. For example, the content of the oxidant is at most 60% by volume based on the total volume of the feedstock containing light alkanes.

[0290] The diluent can be nitrogen, argon, helium, xenon, or carbon monoxide. Preferably, the content of the diluent is at most 70% by volume, more preferably at most 30% by volume, and even more preferably less than 5% by volume based on the total volume of the feedstock containing light alkanes. In some embodiments, there is no diluent in the feedstock containing light alkanes.

[0291] The oxidative coupling reaction of methane with COS and CO2 proceeds as follows:

[0292] 2CH4 + COS → C2H4 + 2H2S + 2CO ΔH = 216.7 kJ

[0293] 2CH4 + COS → C2H6 + H2S + CO ΔH = 73 kJ

[0294] 2CH4 + 2CO2 → C2H4 + 2H2O + 2CO ΔH = 71 kJ

[0295] 2CH4 + CO2 → C2H6 + H2O + CO ΔH = 72 kJ

[0296] The partial oxidation reactions include the possible conversion of alkanes to CO (also known as dry reforming) or CS2, and oxidative dehydrogenation to the corresponding olefins:

[0297] C2H6 + COS → C2H4 + H2S + CO ΔH = 143.5 kJ

[0298] C2H6 + 7COS → 2CS2 + 3H2S + 7CO ΔH = 452.9 kJ

[0299] CH4 + CO2 → 2CO + 2H2 ΔH = 247.8 kJ

[0300] C2H6 + 2CO → 4CO + 3H2 ΔH = 429.8 kJ

[0301] C2H6 + CO2 → C2H4 + H2O + CO ΔH = 133.4 kJ

[0302] C2H6 + 5CO2 → 3H2O + 7CO ΔH = 553.7 kJ

[0303] Depending on the choice of feedstock composition and operating conditions, the resulting effluent may contain unreacted alkanes, unreacted CO2, unreacted COS, olefins, H2S, H2O, CS2, hydrogen, and carbon monoxide. The mixture can be separated by techniques known in the art such as distillation, adsorption, absorption, membrane separation, or flash separation.

[0304] In one embodiment, the conversion of alkanes to olefins is carried out in the absence of a catalytic composition.

[0305] For example, the conversion of alkanes to olefins is carried out at a temperature in the range of 500 °C to 2000 °C, more preferably 550 °C to 1700 °C, even more preferably 600 °C to 1500 °C, or 700 °C to 1300 °C; most preferably 800 °C to 1200 °C, or 900 °C to 1400 °C; and even most preferably 1000 °C to 1500 °C.

[0306] For example, the conversion of the alkanes to olefins is carried out at a pressure in the range of 0.1 MPa to 5.0 MPa, preferably 0.2 MPa to 3.0 MPa.

[0307] For example, the conversion of alkanes to olefins is carried out in the presence of a reaction stream and at a weight hourly space velocity of the reaction stream that is between 0.1 h -1 to 100 h -1 and preferably between 1.0 h -1 to 50 h -1 The residence time of the feedstock containing light alkanes in the fluidized bed section of the reactor where the temperature is 600 to 1500 °C can advantageously be in the range of 0.01 to 0.6 seconds, more preferably 0.1 to 0.3 seconds.

[0308]

[0309] Optional particles of the catalytic composition

[0310] In one embodiment, the conversion of alkanes to olefins is carried out on a catalyst composition. In such an embodiment, the bed contains electrically conductive particles, which may be the same or different, and particles of the catalyst composition.

[0311] For example, based on the total weight of the particles of the bed, the content of the particles of the catalytic composition is in the range of 30 wt% to 100 wt%; preferably 32 wt% to 95 wt%, more preferably 35 wt% to 90 wt%, even more preferably 37 wt% to 85 wt%, most preferably 40 wt% to 80 wt%, even most preferably 45 wt% to 75 wt%, or 50 wt% to 70 wt%. In the case where the content of the particles of the catalytic composition is 100 wt% based on the total weight of the particles of the bed, at least a part of the particles of the catalytic composition is also conductive.

[0312] In one embodiment, the catalyst composition comprises one or more selected from rare earth oxides, rare earth sulfides, transition metal oxides, transition metal sulfides, and any mixture thereof; preferably, the catalyst composition further comprises one or more dopants. The presence or absence of the dopant in the catalyst composition depends on the choice of the oxidant used in the process. When the oxidant is COS, the presence of one or more dopants in the catalyst composition is optional. When the oxidant is CO2, the catalyst composition must comprise one or more dopants.

[0313] The rare earth oxide is one or more selected from scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0314] The transition metal is one or more selected from 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.

[0315] Preferably, the one or more dopants are selected from Eu / Na, Sr / Na, Na / Zr / Eu / Ca, Mg / Na, Sr / Sm / Ho / Tm, Sr / W, Mg / La / K, Na / K / Mg / Tm, Na / Dy / K, Na / La / Dy, Na / La / Eu, Na / La / Eu / In, Na / La / K, Na / La / Li / Cs, K / La, K / La / S, K / Na, Li / Cs, Li / Cs / La, Li / Cs / La / Tm, Li / Cs / Sr / Tm, Li / Sr / Cs, Li / Sr / Zn / K, Li / Ga / Cs, Li / K / Sr / La, Li / Na, Li / Na / Rb / Ga, Li / Na / Sr, Li / Na / Sr / La, Li / Sm / Cs, Ba / Sm / Yb / S, Ba / Tm / K / La, Ba / Tm / Zn / K, Cs / K / La, Cs / La / Tm / Na, Cs / Li / K / La, Sm / Li / Sr / Cs, Sr / Cs / La, Sr / Tm / Li / Cs, Zn / K, Zr / Cs / K / La, Rb / Ca / In / Ni, Sr / Ho / Tm, La / Nd / S, Li / Rb / Ca, Li / K, Tm / Lu / Ta / P, Rb / Ca / Dy / P, Mg / La / Yb / Zn, Rb / Sr / Lu, Na / Sr / Lu / Nb, Na / Eu / Hf, Dy / Rb / Gd, Na / Pt / Bi, Rb / Hf, Ca / Cs, Ca / Mg / Na, Hf / Bi, Sr / Sn, Sr / W, Sr / Nb, Zr / W, Y / W, Na / W, Bi / W, Bi / Cs, Bi / Ca, Bi / Sn, Bi / Sb, Ge / Hf, Hf / Sm, Sb / Ag, Sb / Bi, Sb / Au, Sb / Sm, Sb / Sr, Sb / W, Sb / Hf, Sb / Yb, Sb / Sn, Yb / Au, Yb / Ta, Yb / W, Yb / Sr, Yb / Pb, Yb / W, Yb / Ag, Au / Sr, W / Ge, Ta / Hf, W / Au, Ca / W, Au / Re, Sm / Li, La / K, Zn / Cs, Na / K / Mg, Zr / Cs, Ca / Ce, Na / Li / Cs, Li / Sr, Cs / Zn, La / Dy / K, Dy / K, La / Mg, Na / Nd / In / K, In / Sr, Sr / Cs, Rb / Ga / Tm / Cs, Ga / Cs, K / La / Zr / Ag, Lu / Fe, Sr / Tm, La / Dy, Sm / Li / Sr, Mg / K, Li / Rb / Ga, Li / Cs / Tm, Zr / K, Li / Cs, Li / K / La, Ce / Zr / La, Ca / Al / La, Sr / Zn / La, Sr / Cs / Zn, Sm / Cs, In / K,Ho / Cs / Li / La, Cs / La / Na, La / S / Sr, K / La / Zr / Ag, Lu / Tl, Pr / Zn, Rb / Sr / La, Na / Sr / Eu / Ca, K / Cs / Sr / La, Na / Sr / Lu, Sr / Eu / Dy, Lu / Nb, La / Dy / Gd, Na / Mg / Tl / P, Na / Pt, Gd / Li / K, Rb / K / Lu, Sr / La / Dy / S, Na / Ce / Co, Na / Ce, Na / Ga / Gd / Al, Ba / Rh / Ta, Ba / Ta, Na / Al / Bi, Cs / Eu / S, Sm / Tm / Yb / Fe, Sm / Tm / Yb, Hf / Zr / Ta, Rb / Gd / Li / K, Gd / Ho / Al / P, Na / Ca / Lu, Cu / Sn, Ag / Au, Al / Bi, Al / Mo, Al / Nb, Au / Pt, Ga / Bi, Mg / W, Pb / Au, Sn / Mg, Zn / Bi, Gd / Ho, Zr / Bi, Ho / Sr, Gd / Ho / Sr, Ca / Sr, Ca / Sr / W, Na / Zr / Eu / Tm, Sr / Ho / Tm / Na, Sr / Pb, Ca, Sr / W / Li, Ca / Sr / W, Sr / Hf, or combinations thereof.

[0316] Preferably, the catalyst composition is selected from one of the following: Na-W-Mn / SiO2, NaCl-MnNa2WO4 / SiO2, La2O3-CeO2, Li / MgO, CaO-Sm2O3, KCl-SmCl3, CaO-NaCl / Na2CO3, CeO2 / ZnO, La2O3 / Al2O3, FeS x .

[0317] The metal-containing dopant can react with the oxidants (i.e., COS and CO2) present in the feed stream according to the following equations:

[0318] M x O y + CO2 → M x CO y+2

[0319] M x O y + COS → M x CO y+1 S

[0320] These reactions may be non-stoichiometric and / or involve anion disproportionation, resulting in the formation of a thiocarbonate phase (describing an anion family with the chemical general formula CS 3-x O x 2- (x = 0, 1, or 2)).

[0321] Thus, in one embodiment, the dopant comprises at least one alkali metal, alkaline earth metal, transition metal, post-transition metal, or rare earth metal carbonate or thiocarbonate, or a mixture thereof.

[0322] The catalyst composition may further comprise a support and / or a binder. Suitable particulate catalyst supports are refractory oxides such as alumina (Al2O3), titanium dioxide (TiO2), zirconia (ZrO2), hafnia (HfO2), lanthanum oxide (La2O3), magnesia (MgO), cerium dioxide (CeO2), yttrium oxide (Y2O3), preferably zirconia, lanthanum oxide, yttrium oxide or cerium dioxide stabilized with magnesia; metal aluminates such as calcium aluminate and magnesium aluminate; and mixtures thereof. Particularly preferred particulate catalyst supports comprise alumina and / or stabilized zirconia, such as alumina stabilized with lanthanum oxide, ceria-zirconia-alumina, ceria-titania-alumina and ceria-magnesia-alumina materials. Preferred support materials are those common materials (mentioned above) that can be used for both resistance heating and can be subdivided into two main categories: (1) metal alloys; and (2) non-metallic resistors such as silicon carbide (SiC) and molybdenum disilicide (MoSi2), various mixed oxides with variable optimum temperatures, and carbon such as graphite. This latter option results in close contact between the catalytically active metal and the resistor particulate material.

[0323] Particulate catalyst support particles preferably have a particle size in the range of 5 to 300 μm, more preferably 10 to 200 μm, and most preferably 30 to 150 μm. The catalyst can be dispersed on the surface of the particulate catalyst support by conventionally impregnating a soluble metal compound onto the particulate catalyst support, followed by drying and calcining to convert one or more catalytic metal compounds into their corresponding oxides. Subsequent sulfidation in a stream of a suitable sulfiding agent (e.g., H2S or DMS) will result in the formation of the corresponding sulfide.

[0324] Alternatively, the catalytic metal or metal precursor can be dispersed on the surface of the particulate catalyst support material by using metal sol precipitation, or by the deposition-precipitation method, using metal salts that deposit insoluble metal compounds from solution onto the particulate catalyst support upon heating. In addition, the metal salt can be ion-exchanged with counter cations on the support material. The metal precursor is reduced to the metallic state at high temperature by using hydrogen, carbon monoxide or a hydrocarbon as a reducing agent. This can be carried out before loading the catalyst into the fluidized bed reactor or in situ in the fluidized bed before or during feeding the feedstock.

[0325] The catalyst composition may comprise a binder. Preferably, one or more of the following can be used to further define the binder:

[0326] - The binder is selected from silica, alumina, clay, alumina phosphate, calcium phosphate, magnesium phosphate, mullite, and any mixture thereof.

[0327] - The binder is or contains silica.

[0328] - The binder is present in an amount of at least 5 wt%, or at least 10 wt%, preferably at least 20 wt%, most preferably at least 30 wt%, even more preferably at least 40 wt%, and most preferably at least 50 wt% based on the total weight of the catalyst composition.

[0329] - The binder is present in an amount in the range of 5 wt% to 75 wt% based on the total weight of the catalyst composition; preferably in the range of 10 to 75 wt%; more preferably in the range of 12 to 65 wt%; even more preferably in the range of 15 to 60 wt%; most preferably in the range of 18 to 50 wt%; even most preferably in the range of 20 to 40 wt%; for example, in the range of 15 to 30 wt% or in the range of 10 to 50 wt%.

[0330] Equipment

[0331] The terms "bottom" and "top" should be understood with respect to the overall orientation of the device or the fluidized bed reactor. Thus, "bottom" will mean closer to the ground along the vertical axis than "top". In different figures, the same reference numerals designate the same or similar elements.

[0332] Figure 1 There is shown a prior art fluidized bed reactor 1, which comprises a reaction vessel 3, a bottom fluid nozzle 5 for introducing a fluidizing gas and a feedstock containing light alkanes, an optional inlet 7 for material loading, an optional outlet 9 for material discharge, and a gas outlet 11 and a bed 15. In Figure 1 the fluidized bed reactor 1, heat is provided by preheating the feedstock by burning a fossil fuel using a heating device 17, which is arranged, for example, at the level of a pipeline supplying the fluidizing gas and the feedstock containing light alkanes to the reactor.

[0333] Now refer to Figures 2 to 5 to describe the device of the present invention. For simplicity, the internal devices used in the fluidized bed reactor are known to those skilled in the art, such as bubble breakers, guide plates (deflection plates), particle terminal devices, cyclone separators, ceramic wall coatings, thermocouples, etc... and are not shown in the figures. Figures 2 to 5 There is shown an energized fluidized bed unit.

[0334] Figure 2Shows a first apparatus having a fluidized bed reactor 19, where the heating and reaction zones are the same. The fluidized bed reactor 19 includes a reaction vessel 3, a bottom fluid nozzle 21 for introducing a fluidizing gas and a feedstock containing light alkanes, an optional inlet 7 for material loading, an optional outlet 9 for material discharge, and a gas outlet 11. Figure 2 The fluidized bed reactor 1 shows two electrodes 13 immersed in the bed 25.

[0335] Figure 3 Shows an embodiment where at least one fluidized bed reactor 19 includes a heating zone 27 and a reaction zone 29, where the heating zone 27 is the bottom zone and the reaction zone 29 is on top of the heating zone 27. One or more fluid nozzles 23 supply a feedstock containing light alkanes to the reaction zone from a distributor 33. As Figure 3 can be seen, one or more fluid nozzles 23 can be connected to the distributor 33 to distribute the feedstock containing light alkanes inside the bed 25.

[0336] Figure 4 Shows an apparatus where at least one fluidized bed reactor 18 includes at least two lateral zones, where the outer zone is the heating zone 27 and the inner zone is the reaction zone 29. The heated particles of the bed 25 from the outer zone are transferred to the inner zone through one or more openings 41 and mixed with the feedstock containing light alkanes. At the end of the reaction zone, the particles are separated from the reaction products and transferred to the heating zone.

[0337] Figure 5 Shows an apparatus including at least two fluidized bed reactors (37, 39) connected to each other, where at least one fluidized bed reactor is the heating zone 27 and at least one fluidized bed reactor is the reaction zone 29.

[0338] The present disclosure provides an apparatus for use in a process of converting alkanes to olefins, the apparatus including an energized fluidized bed unit having at least one fluidized bed reactor (18, 19, 37, 39), the fluidized bed reactor including:

[0339] - at least two electrodes 13,

[0340] - a reaction vessel 3;

[0341] - one or more fluid nozzles (21, 23) for introducing a fluidizing gas and / or a feedstock containing light alkanes into at least one fluidized bed reactor (18, 19, 37, 39); and

[0342] - a bed 25 containing particles;

[0343] Based on the total weight of the particles of the bed 25, at least 10% by weight of the particles of the bed are conductive and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C.

[0344] When the process of converting alkanes into olefins further includes a sub-step of generating a stream containing COS, the apparatus for performing the partial oxidation reaction and / or oxidative coupling reaction of light alkanes includes:

[0345] - A CO2 sulfidation unit including one or more conversion reactors,

[0346] - An optional separation unit,

[0347] - An energized fluidized bed unit, which includes at least one fluidized bed reactor (18, 19, 37, 39), and the fluidized bed reactor includes: at least two electrodes 13; a reaction vessel 3; one or more fluid nozzles (21, 23) for introducing a fluidizing gas and / or a raw material stream containing light alkanes into at least one fluidized bed reactor; and a bed containing particles; based on the total weight of the particles of the bed, at least 10% by weight of the particles of the bed are conductive and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at a temperature of 800 °C;

[0348] And the CO2 sulfidation unit, the separation unit when present, and the energized fluidized bed unit are connected in series in fluid connection in the order mentioned.

[0349] For example, the conductive particles of the bed are or include one or more selected from the following: one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more carbon-containing particles, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0350] For example, the conductive particles of the bed are or include one or more selected from the following: one or more metal alloys, one or more non-metal resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, graphite, carbon black, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

[0351] In one embodiment, based on the total weight of the conductive particles of the bed, 50 wt% to 100 wt%; preferably 60 wt% to 100 wt%; more preferably 70 wt% to 100 wt%; even more preferably 80 wt% to 100 wt%, and most preferably 90 wt% to 100 wt% of the conductive particles of the bed are one or more selected from the following: graphite, carbon black, one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valence cations, one or more mixed sulfides doped with one or more low-valence cations, and any mixture thereof.

[0352] For example, one electrode is a submerged central electrode, or two electrodes 13 are submerged in the reaction vessel 3 of at least one reactor (18, 19, 37).

[0353] For example, the fluidizing gas is one or more dilution gases.

[0354] In a preferred embodiment, at least one fluidized bed reactor (18, 19, 37, 39) has no heating device. For example, at least one fluidized bed reactor has no heating device selected from an oven, a gas burner, a hot plate, or any combination thereof. For example, all fluidized bed reactors have no heating device selected from an oven, a gas burner, a hot plate, or any combination thereof. In a preferred embodiment, at least one fluidized bed reactor comprising at least two electrodes and a bed containing particles has no structured packing, such as a honeycomb monolith or a cross plate.

[0355] For example, the reaction vessel 3 has an inner diameter of at least 100 cm, or at least 200 cm; or at least 400 cm. Such a large diameter allows chemical reactions to be carried out on an industrial scale. For example, the weight hourly space velocity of the reaction stream is included between 0.1 h -1 to 100 h -1 and preferably included between 1.0 h -1 to 50 h -1 The weight hourly space velocity is defined as the ratio of the mass flow rate of the reaction stream to the mass of the solid particle material in the fluidized bed.

[0356] At least one fluidized bed reactor (18, 19, 37) comprises at least two electrodes 13. For example, one electrode is electrically connected to the outer wall of the fluidized bed reactor, while an additional electrode is immersed in the fluidized bed 25, or both electrodes 13 are immersed in the fluidized bed 25. The at least two electrodes 13 are electrically connected and connectable to a power source (not shown). Advantageously, the at least two electrodes 13 are made of graphite. Those skilled in the art will have the advantage that the electrodes 13 are more conductive than the particle bed 25.

[0357] For example, at least one electrode 13 is made of graphite or comprises graphite; preferably, all or two electrodes 13 are made of graphite. For example, one of the electrodes is the reaction vessel such that the reactor comprises two electrodes, one being an immersed central electrode, and one being the reaction vessel 3.

[0358] For example, at least one fluidized bed reactor comprises at least one cooling device which is arranged to cool at least one electrode.

[0359] During use of the fluidized bed reactor, a voltage of at most 300 V, preferably at most 250 V, more preferably at most 200 V, even more preferably at most 150 V, most preferably at most 100 V, even most preferably at most 90 V, or at most 80 V is applied.

[0360] Due to the fact that the current source can be adjusted, it is easy to adjust the temperature within the reactor bed.

[0361] The reaction vessel 3 can be made of graphite. In one embodiment, it can be made of a resistive material which is silicon carbide or a mixture of silicon carbide and graphite.

[0362] Preferably, the reaction vessel 3 comprises a reactor wall made of a material which is a corrosion-resistant material, and advantageously, the reactor wall material comprises nickel (Ni), SiAlON ceramic, yttria-stabilized zirconia (YSZ), tetragonal polycrystalline zirconia (TZP) and / or tetragonal zirconia polycrystal (TPZ). SiAlON ceramic is a ceramic based on the elements silicon (Si), aluminum (Al), oxygen (O) and nitrogen (N). They are solid solutions of silicon nitride (Si3N4) in which the Si-N bonds are partially replaced by Al-N and Al-O bonds.

[0363] For example, the reaction vessel 3 is made of a resistive material which is a mixture of silicon carbide and graphite; and the resistive material of the reaction vessel 3 comprises 10 wt% to 99 wt% based on the total weight of the resistive material; preferably, 15 wt% to 95 wt%, more preferably 20 wt% to 90 wt%, even more preferably 25 wt% to 80 wt%, and most preferably 30 wt% to 75 wt% of silicon carbide.

[0364] For example, the reaction vessel 3 is made of a resistive material that is a mixture of silicon carbide and graphite.

[0365] For example, the reaction vessel 3 is non-conductive. For example, the reaction vessel 3 is made of ceramic.

[0366] For example, at least one fluidized bed reactor (18, 19, 37, 39) comprises a heating zone 27 and a reaction zone 29, one or more fluid nozzles 21 for supplying a fluidizing gas from a distributor 31 to at least the heating zone, one or more fluid nozzles 23 for supplying a feedstock containing light alkanes from a distributor 33 to the reaction zone, and optionally means 41 for transporting particles from the heating zone 27 to the reaction zone 29, and optionally means 35 for transporting particles from the reaction zone 29 back to the heating zone 27.

[0367] For example, as Figure 3 shown, at least one fluidized bed reactor is a single fluidized bed reactor 19, wherein the heating zone 27 is the bottom part of the fluidized bed reactor 19 and the reaction zone 29 is the top part of the fluidized bed reactor 19; preferably, the apparatus comprises one or more fluid nozzles 23 for injecting a feedstock containing light alkanes between the two zones (27, 29) or in the reaction zone 29. The fluidized bed reactor 19 further comprises an inlet 7 for optionally loading material, an outlet 9 for optionally discharging material, and a gas outlet 11. Preferably, the fluidized bed reactor 19 has no heating means. For example, an electrode 13 is arranged at the bottom part of the fluidized bed reactor 19, i.e., in the heating zone 27. For example, the top of the fluidized bed reactor 19 (i.e., the reaction zone 29) has no electrode. Optionally, the fluidized bed reactor 19 comprises means 35 for transporting particles from the reaction zone 29 back to the heating zone 27; for example, by means of a pipeline arranged between the top part and the bottom part of the fluidized bed reactor 19.

[0368] For example, as Figure 4As shown, the apparatus comprises at least two laterally connected fluidized bed zones (27, 29), where at least one fluidized bed zone 27 is a heating zone and at least one fluidized bed zone 29 is a reaction zone. For example, the heating zone 27 surrounds the reaction zone 29. Preferably, the apparatus comprises one or more fluid nozzles 23 which are arranged to inject a feedstock containing light alkanes into at least one reaction zone 29 using a distributor 33. The fluidized bed zones (27, 29) further comprise an inlet 7 for optionally loading material and a gas outlet 11. Preferably, at least one fluidized bed zone serving as the heating zone 27 and / or at least one fluidized bed zone serving as the reaction zone 29 has no heating means. For example, at least one fluidized bed zone serving as the reaction zone 29 shows an outlet 9 for optionally discharging material. One or more fluid nozzles 21 supply fluidizing gas from a distributor 31 to at least the heating zone. Using one or more inlet means 41, heated particles are transported from the heating zone 27 to the reaction zone 29, and using one or more means 35 comprising downcomers, separated particles are transported from the reaction zone 29 back to the heating zone 27. The fluidizing gas for the heating zone 27 can be an inert diluent, such as one or more selected from steam, hydrogen, carbon dioxide, methane, argon, helium, and nitrogen. In such a configuration, the fluidizing gas for the heating zone can also contain air or oxygen to burn deposited coke from the particles.

[0369] For example, as Figure 5 As shown, the apparatus comprises at least two connected fluidized bed reactors (37, 39), where at least one fluidized bed reactor 37 is the heating zone 27 and at least one fluidized bed reactor 39 is the reaction zone 29. Preferably, the apparatus comprises one or more fluid nozzles 23 which are arranged to inject a feedstock containing light alkanes into at least one fluidized bed reactor 39 serving as the reaction zone 29. The fluidized bed reactors (37, 39) further comprise an inlet 7 for optionally loading material and a gas outlet 11. Preferably, at least one fluidized bed reactor 37 serving as the heating zone 27 and / or at least one fluidized bed reactor 39 serving as the reaction zone 29 has no heating means. For example, at least one fluidized bed reactor 39 serving as the reaction zone 29 shows an outlet 9 for optionally discharging material. When necessary, using inlet means 41, heated particles are transported from the heating zone 27 to the reaction zone 29, and using means 35, separated particles after the reaction zone are transported from the reaction zone back to the heating zone. The fluidizing gas for the heating zone can be an inert diluent, such as one or more selected from steam, hydrogen, carbon dioxide, methane, argon, helium, and nitrogen. In such a configuration, the fluidizing gas for the heating zone can also contain air or oxygen to burn deposited coke from the particles.

[0370] For example, at least one fluidized bed reactor 37 as the heating zone 27 includes at least two electrodes 13, while at least one fluidized bed reactor 39 as the reaction zone 29 has no electrodes.

[0371] For example, at least two fluidized bed reactors (37, 39) are connected to each other by means 41 (such as one or more pipelines) suitable for transporting particles from the heating zone 27 to the reaction zone 29.

[0372] For example, at least two fluidized bed reactors (37, 39) are connected to each other by means 35 (such as one or more pipelines) suitable for transporting particles from the reaction zone 29 back to the heating zone 27.

Claims

1. A process for converting alkanes into olefins; the process comprising the following steps: a) providing a stream of a feedstock containing light alkanes, the stream of the feedstock containing light alkanes containing one or more alkanes selected from methane, ethane, propane, butane, isobutane, and any mixture thereof, and one or more oxidants selected from carbon dioxide, carbonyl sulfide, and any mixture thereof; wherein the oxidant content is at least 15% by volume based on the total volume of the feedstock containing light alkanes; and further providing at least one fluidized bed reactor, the fluidized bed reactor comprising at least two electrodes and a bed containing particles; b) fluidizing the particles of the bed to obtain a fluidized bed; c) heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C to effect the conversion of the feedstock containing light alkanes into olefins; and d) optionally recovering the product of the reaction; characterized in that step c) of heating the fluidized bed is carried out by passing an electric current through the fluidized bed; the particles of the bed comprise conductive particles and particles of a catalytic composition; at least 10% by weight of the particles are conductive particles and have a resistivity in the range of 0.001 Ohm.cm to 500 Ohm.cm at 800 °C based on the total weight of the particles of the bed; the porosity of the bed is in the range of 0.5 to 0.8, and the particles of the bed have an average particle size in the range of 5 to 300 μm when determined by sieving according to ASTM D4513-11; In addition, the catalyst composition comprises one or more selected from rare earth sulfides, transition metal oxides, and any mixtures thereof, and / or one or more selected from Na-W-Mn / SiO2, NaCl-MnNa2WO4 / SiO2, Li / MgO, CaO-Sm2O3, KCl-SmCl3, CaO-NaCl / Na2CO3, La2O3 / Al2O3, and FeS x When one of the oxidants of the raw material containing light alkanes is carbon dioxide, the catalyst composition further comprises one or more dopants.

2. The process according to claim 1, characterized in that, The catalyst composition comprises rare earth oxides.

3. The process according to claim 1, characterized in that, The catalyst composition comprises one or more selected from La2O3-CeO2 and CeO2 / ZnO.

4. The process according to claim 1, characterized in that, The conductive particles of the bed are selected from: one or more metal alloys, one or more non-metallic resistors, one or more metal carbides, one or more transition metal nitrides, one or more metal phosphides, one or more carbon-containing particles, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides doped with one or more low-valent cations, one or more mixed sulfides doped with one or more low-valent cations, and any mixture thereof.

5. The process according to any one of claims 1 to 4, characterized in that, The conductive particles of the bed comprise one or more carbon-containing particles that are graphite, and / or the conductive particles of the bed comprise one or more non-metallic resistors selected from silicon carbide, molybdenum disilicide, or a mixture thereof.

6. The process according to any one of claims 1 to 4, characterized in that, The conductive particles of the bed comprise a mixture of a non-metallic resistor that is silicon carbide and conductive particles different from silicon carbide.

7. The process according to claim 6, characterized in that, Based on the total weight of the conductive particles of the bed, the conductive particles of the bed comprise 10% to 99% by weight of silicon carbide; and / or The conductive particles different from silicon carbide are one or more carbon-containing particles and / or one or more mixed oxides doped with one or more low-valent cations and / or one or more mixed sulfides doped with one or more low-valent cations.

8. The process according to any one of claims 1 to 4, characterized in that, The conductive particles of the bed comprise one or more mixed oxides doped with one or more low-valent cations.

9. The process according to claim 8, characterized in that, The mixed oxides are selected from: -One or more oxides having a cubic fluorite structure, wherein the cubic fluorite structure is at least partially substituted by one or more low-valence cations; and / or -One or more ABO3 perovskites having A and B trivalent cations, wherein the ABO3 perovskite is at least partially substituted by one or more low-valence cations at the A site; and contains at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe, and / or mixtures thereof at the B site; and / or -One or more ABO3 perovskites having A divalent cations and B tetravalent cations, wherein the ABO3 perovskite is at least partially substituted by one or more low-valence cations at the B site, or is substituted by a mixture of different B elements at the B site; and / or -One or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, wherein the A2B2O7 pyrochlore is at least partially substituted by one or more low-valence cations at the A site, and contains at least one of Sn, Zr, and Ti at the B site.

10. The process according to claim 9, characterized in that, For the one or more oxides having a cubic fluorite structure, the low-valence cations are selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, or Eu.

11. The process according to claim 9, characterized in that, For the one or more ABO3 perovskites having A and B trivalent cations, the low-valence cations are selected from Ca, Sr, or Mg.

12. The process according to claim 9, characterized in that, For the one or more ABO3 perovskites having A divalent cations and B tetravalent cations, the low-valence cations are selected from Mg, Sc, Y, Nd, or Yb.

13. The process according to claim 9, characterized in that, For the one or more A2B2O7 pyrochlore having A trivalent cations and B tetravalent cations, the low-valence cations are selected from Ca or Mg.

14. The process according to any one of claims 1 to 4, characterized in that, The conductive particles of the bed comprise: -One or more metal alloys; and / or -One or more superionic conductors.

15. The process according to claim 14, characterized in that, One or more superionic conductors are selected from LiAlSiO4, Li 10 GeP2S 12 , L i3.6 Si 0.6 P 0.4 O4, sodium superionic conductors, or sodium beta-alumina.

16. The process according to any one of claims 1 to 4, characterized in that, The catalyst composition comprises one or more selected from rare earth sulfides, transition metal oxides, transition metal sulfides, and any mixtures thereof, and the catalyst composition comprises one or more dopants.

17. The process according to claim 16, characterized in that, The catalyst composition comprises rare earth oxides.

18. The process according to claim 16, characterized in that, The one or more dopants comprise at least one alkali metal, alkaline earth metal, transition metal, or post-transition metal carbonate or thiocarbonate, or any mixtures thereof.

19. The process according to claim 18, characterized in that, The one or more dopants comprise at least one rare earth metal.

20. The process according to any one of claims 1 to 4, characterized in that, The porosity of the bed is in the range of 0.5 to 0.

7.

21. The process according to any one of claims 1 to 4, characterized in that, When determined by sieving according to ASTM D4513-11, the particles of the bed have an average particle size in the range of 10 to 200 μm.

22. The process according to any one of claims 1 to 4, characterized in that, In step b), the particles of the bed are fluidized by passing a gaseous stream containing methane upward through the bed; and / or it includes a step of preheating the one or more fluidized bed reactors with a gaseous stream before performing the partial oxidation reaction and / or oxidative coupling reaction of the alkane in the fluidized bed reactor, wherein the gaseous stream has a temperature comprised between 400 °C and 1000 °C.

23. The process according to any one of claims 1 to 4, characterized in that, The at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone, and the step c) of heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C for carrying out the partial oxidation reaction and / or oxidative coupling reaction of alkanes comprises the following sub-steps: - heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C by passing an electric current through the heating zone of the at least one fluidized bed; - conveying the heated particles from the heating zone to the reaction zone; - in the reaction zone, fluidizing the heated particles by passing a stream comprising a feedstock containing light alkanes and optionally a diluent gas upward through the bed of the reaction zone to obtain a fluidized bed for the conversion of the light-alkane-containing feedstock from alkanes to olefins; - optionally, withdrawing the particles from the reaction zone and recycling them to the heating zone.

24. The process according to any one of claims 1 to 4, characterized in that, The at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone, and the step c) of heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C for carrying out the conversion of alkanes to olefins comprises the following sub-steps: - preheating the fluidized bed to a range of 400 °C to 1000 °C by passing an upwardly flowing fluidized stream through a bed of particles, the fluidized stream being a gaseous stream having a temperature in the range of 400 °C to 1000 °C; - heating the fluidized bed to a temperature in the range of 600 °C to 1500 °C by passing an electric current through the heating zone; - conveying the heated particles from the heating zone to the reaction zone; - in the reaction zone, fluidizing the heated particles by passing a stream comprising a feedstock containing light alkanes and optionally a diluent gas upward through the bed of the reaction zone to obtain a fluidized bed for the conversion of the light-alkane-containing feedstock from alkanes to olefins; - optionally, withdrawing the particles from the reaction zone and recycling them to the heating zone.

25. The process according to any one of claims 1 to 4, characterized in that, Step a) includes a sub-step of generating a stream containing carbonyl sulfide, wherein the sub-step includes providing a feed stream containing at least 30 wt% carbon dioxide and at least 20 wt% hydrogen sulfide, based on the total weight of the feed stream, and converting the feed stream into a stream containing carbonyl sulfide; wherein the conversion is carried out at a temperature in the range of 50 to 800 °C, at a pressure in the range of 0.01 to 5 MPa, and at a GHSV in the range of 0.1 to 10 h -1 -1, wherein the stream containing carbonyl sulfide contains water and at least 10 wt% carbonyl sulfide, based on the total weight of the stream containing carbonyl sulfide.

26. The process according to claim 25, characterized in that, The sub-step of generating a stream containing carbonyl sulfide is carried out in the presence of a carbonyl sulfide conversion catalyst and at least one adsorbent.

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