WO2022023365A1

WO2022023365A1 - Process to conduct an endothermic thio-reforming reaction of hydrocarbons in an installation comprising electrified fluidized bed reactor

Info

Publication number: WO2022023365A1
Application number: PCT/EP2021/071047
Authority: WO
Inventors: Gleb VERYASOV; Nikolai Nesterenko; Walter Vermeiren
Original assignee: Totalenergies Se
Priority date: 2020-07-28
Filing date: 2021-07-27
Publication date: 2022-02-03

Abstract

The present disclosure relates to a process for an endothermic thio-reforming reaction of hydrocarbons, said process is remarkable in that it comprises: (a) providing at least one fluidized bed reactor comprising at least two electrodes and a bed comprising particles; (b) putting the particles in a fluidized state to obtain a fluidized bed; (c) heating the fluidized bed to a temperature ranging from 500°C to 1200°C; (d) obtaining an effluent comprising hydrogen and carbon disulphide; and wherein the bed comprises electrically conductive particles and catalytic particles, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and wherein the step (c) of heating is performed by passing an electric current through the fluidized bed.

Description

Process to conduct an endothermic thio-reforming reaction of hydrocarbons in an installation comprising electrified fluidized bed reactor

Technical field

The present disclosure relates to a process for performing an endothermic thio-reforming reaction of hydrocarbons in an installation comprising at least one fluidized bed reactor, the process is performed without the need of an external heating device in the said fluidized bed reactor. The present disclosure aims to contribute to the replacement of the use of fossil carbon-based fuels heating devices. The present disclosure relates to the electrification of the chemical industry.

Technical background

Climate change and ongoing energy transition make it mandatory to replace fossil carbon- based fuels in chemical production and recycled processes with a more environmentally friendly decarbonized source of energy. Transforming natural gas into valuable chemicals requires elevated temperature, often higher than 800°C and even up to 1000°C and are often endothermic. The energy needed is, therefore, high and not often environmentally friendly, as is demonstrated by the common use of fired heated reactors. Several studies have been undertaken to reduce the burden imposed by these (harsh) reaction conditions.

The study of Asensio J. M. et al., entitled “Hydrodeoxygenation using magnetic induction: high- temperature heterogeneous catalysis in solution” ( Angew . Chem. Int. Ed., 2019, 58, 1-6) describes the use of magnetic nanoparticles as heating agents to improve the energy efficiency of reactions performed at high temperature, as the heat can be then directly and homogeneously transferred to the medium without the need for heating the reactor walls. This was applied in the hydrodeoxygenation of ketones. However, in such a system, relatively low temperatures up to 280°C were reached and the reaction is exothermic.

In the study of Wismann S.T. et al., entitled “Electrified methane reforming: A compact approach to greener industrial hydrogen production ” ( Science , 2019, 364, 756-759), a conventional fired reactor was replaced by an electric-resistance-heated reactor. A laboratory- scale reactor based on FeCrAI alloy tube having a diameter of 6 mm and coated with a 130- pm nickel-impregnated washcoat was used to carry out steam methane reforming. As the heat source and the wall of the tube are one, it is possible to minimize the loss of heat and then to render more efficient and more economical the process of steam methane reforming. Temperatures with a maximum of 800°C were reached with this kind of reactor. In the study of Malerod-Fjeld H. et ai, entitled “Thermo-electrochemical production of compressed hydrogen from methane with near-zero energy loss ” (Nat. Energy, 2017, 2, 923- 931), a ceramic tube, having an outer diameter of 1 cm and made of a perovskite derivative, is used as the electrolyte. By applying a voltage and hence a current across the electrolyte, hydrogen can be selectively extracted from methane and steam. The perovskite derivative is supplemented with nickel nanoparticles to provide the catalyst necessary for the reaction.

In the study of Varsano F. et ai, entitled “Dry reforming of methane powered by magnetic induction ” ( Int . J. of Hydrogen Energy, 2019, 44, 21037-21044), electromagnetic induction heating of catalytic heterogeneous processes was used and has been demonstrated as bringing several advantages in terms of process intensification, energy efficiency, reactor setup simplification and safety issues coming from the use of radiofrequency. Temperatures ranging between 850°C and 900°C in reactors having 1 cm of inner diameter can be reached using NίboOqbo pellets as heat mediators in a continuous-flow fixed-bed reactor.

These examples show that progress exists in the field of transforming fossils sources into valuable chemicals with the perspective to diminish the impact on the climate. However, this progress has not been developed to a large scale as it is rather limited to the laboratory environment.

With regards to this matter, the Shawinigan process, described in CA 573348, relates to a process to prepare hydrocyanic acid from ammonia using in a fluidized bed reactor made of high temperature-resistant silica glass and comprising conductive carbon particles, such as coke and/or petroleum coke. The principle resides in that the electricity is used to heat the conductive carbon particles which can maintain the fluidized bed at a temperature sufficient to transform ammonia into hydrocyanic acid, which is then recovered from the outgoing gas coming off the fluidized bed. The inner diameter of the reactor tube was 3.4 cm. A temperature ranging between 1300°C and 1600°C, sufficient to perform the requested reaction, can be reached by using such conductive carbon particles.

US 2,982,622 describes a method for producing hydrogen and high quality coke which comprises passing inert solid particles as a relatively dense mass downwardly through an elongated reaction zone, applying an electrical voltage of 0.1 to 1000 volts per inch across at least a portion of said solids mass in said reaction zone, said voltage being sufficient to raise the temperature of said solids to 1800 to 3000 F. due to their resistance to the flow of electricity without causing substantial electrical spark discharges through said solids mass, downwardly withdrawing thus heated solids from said reaction zone, pre-heating a hydrocarbon feed by heat exchange with said withdrawn solids and introducing said preheated feed into and upwardly through said reaction zone in the form of an upwardly moving gasiform stream, said feed contacting said heated solids and being converted to light vapors including a substantial portion of hydrogen and carbon which deposits on said solids, heat exchanging hot vapors withdrawn from said reaction zone with inert solids in a heating zone, circulating at least a portion of the solids withdrawn from the reaction zone and previously heat exchanged with said feed to said heating zone, passing solids from said heating zone to said reaction zone as solids feed thereto, and recovering at least a portion of the solids withdrawn from the reaction zone as product and recovering hydrogen gas and light vapors from the upper portion of said reaction zone.

US3259565 describes a process for converting hydrocarbons to produce lower boiling hydrocarbons and solid coke particles of a size larger than fluidizable size which comprises passing coke agglomerates down through a hot fluidized bed of coke particles, introducing hydrocarbon oil feed into said fluidized bed to crack the hydrocarbon oil, passing cracked vaporous products overhead, removing coke agglomerates from said fluid bed and passing them down through a heat exchanger zone in countercurrent contact with said withdrawn cracked vaporous products to cool said cracked vaporous products and to heat said coke agglomerates while condensing and depositing higher boiling hydrocarbons from said cracked vaporous products on said coke agglomerates, withdrawing resulting cracked vaporous products as product, recirculating the so treated coke agglomerates a number of times through said heat exchange zone to deposit hydrocarbons and through said hot fluidized coke bed to coke the deposited high boiling hydrocarbons and to increase the size of the coke agglomerates, withdrawing coke agglomerates of increased size as product from the system.

The disclosure of US 2017/0158516 described a fluidized-bed reactor made of silicon carbide for preparing granular polycrystalline silicon at the industrial level. The fluidized-bed reactor is heated using a heating device which is placed in an intermediate jacket between the outer wall of the reactor tube and the inner wall of the reactor vessel. Such intermediate jacket comprises an insulation material and is filled or flushed with an inert gas. It was found that the use of sintered silicon carbide (SSiC) having a SiC content of 98% by weight as the main element of the reactor tube with a high purity SiC coating deposited by chemical vapour deposition allowed reaching high temperature up to 1200°C without the tube being corroded. It was also found that using siliconized silicon carbide (SiSiC) as the main element of the reactor tube without any surface treatment, such as the deposition of a coating layer, led to the tube being corroded.

On the other hand, the disclosure of Goldberger W. M. et al., entitled “The electrothermal fluidized bed’ ( Chem . Eng. Progress, 1965, 61 (2), 63-67, relates to fluidized-bed reactor made in graphite and susceptible to perform reactions such as the hydrocracking of hydrocarbons, the pyrolysis of organics, the production of elemental phosphorus or the chlorination of zirconium oxide. Operation at temperatures up to about 4400°C appears possible. However, it is not certain that from a long-term perspective, the graphite material used to design the fluidized-bed reactor can resist such harsh reaction conditions. Indeed, in the study of Uda T. et ai, entitled “Experiments on high-temperature graphite and steam reactions under loss of coolant accident conditions", ( Fusion Engineering and Design, 1995, 29, 238-246), it has been shown that graphite corrodes under conditions involving steam and elevated temperature, for instance between 1000°C and 1600°C. Also, as shown in the study of Qiao M-X. et ai, entitled “Corrosion of graphite electrode in electrochemical advanced oxidation processes: degradation protocol and environmental application", ( Chem . Eng. J., 2018, 344, 410-418), the graphite is susceptible to carbon oxidation reaction, which impacts its activity as an electrode by restricting notably the voltage that can be applied to it.

A hydrocarbon reformer is a device based on steam reforming (SR), autothermal reforming (ATR) or partial oxidation (POx) in presence of steam and/or oxygen using a catalyst (usually nickel) at high temperature and pressure. The available reforming technologies differentiate by the way of getting the heat into the process or the means of heat transfer: convective heat transfer, radiant heat transfer and internal combustion.

1. Steam reforming (SR), being very endothermic, uses an external source of heat to heat multiple tubes, containing the catalyst that converts steam and light hydrocarbons into hydrogen and carbon monoxide (syngas). Steam reforming of light hydrocarbons, in particular of methane (SMR) for the production of synthesis gas are well known. The steam methane reforming process involves reacting a hydrocarbon feedstock (such as natural gas, refinery gas, or naphtha) with steam at elevated temperatures (up to about 1050°C) and in the presence of a catalyst to produce a gas mixture primarily composed of hydrogen and carbon monoxide, commonly known as syngas or synthesis gas. The hydrocarbon feedstock can be any that can be vaporised and can be desulphurized to permit the catalytic reaction with steam. Usually, it has a boiling point under 250°C and preferably it is gaseous, natural gas is most suitable.

The synthesis gas exiting the reformer contains carbon monoxide (CO) along with hydrogen, carbon dioxide (C0₂), steam and unconverted methane according to the equilibria (thermodynamically controlled) established in the following reactions:

CH₄+ H2O *± 3H₂+ CO Steam Reforming, endothermic, DH_G -206 kJ/mol H₂0 + C0 ?± H2+ CO2 Water Gas Shift, exothermic, DH_G= 41 kJ/mol

CH4 + CO2 ^ 2 H2+ 2 CO CO2 Reforming, endothermic, DH_G= -247 kJ/mol

Therefore, the reformer effluent composition depends on several variables including pressure, temperature, the molar ratio of steam/methane in the reactor feed and carbon dioxide concentration in the reactor feed. These reactions are generally carried out at high temperatures (700°C-1050°C) and high pressures (5-30 atmospheres) wherein the reactants are contacted with a metal-based catalyst. A typical SMR effluent composition (mole fractions) is composed of 73% H2, 13% CO, 8.5% CO2 and 5.5% CH4 when the SMR reaction is conducted at 850°C and 25 atmospheres using a CO2- free feed mixture containing a 3:1 water/methane molar ratio. The final hydrogen to carbon monoxide ratio can be controlled by adding carbon dioxide to the feed. The furnace consists of a box-type radiant section including the burners and a convection section to recover the waste heat of the flue gases leaving the radiant section. In the radiant section, a nickel catalyst is loaded in several high alloy reforming tubes placed in rows along with the furnace. The outer diameter of the tubes ranges typically from 5 to 25 cm and the length is from 10 to 15 m. Typical inlet temperatures to the catalyst bed are 450-650°C, and product syngas leaves at 800-950°C. Tubular reformers are designed with a variety of tube and burner arrangements, including side-fired furnaces, top-fired furnaces and terrace wall furnaces. The necessary heat for the reaction is supplied from the outside of the tubes usually by a combination of radiation and convection to the outer wall of the reformer tube. Subsequently, the heat is transferred to the inner side of the tube by heat conduction through the tube wall and is transferred to the gas phase by convection. Finally, the heat is transferred from the gas phase to the catalyst pellet by convection. The catalyst temperature can be more than 100°C lower than the inner tube wall temperature. The heat required in the tubular reformer (and hence the cost) may be reduced by increased preheat temperature. When higher hydrocarbons, like ethane, propane or naphtha-type molecules, are present in the feed during preheat steam cracking can result in olefins that easily form carbon in the reformer. In such cases, an adiabatic pre-reformer is added where the higher hydrocarbons are reformed into synthesis gas in the temperature range of 350-600°C, at which conditions the reforming and shift reactions are equilibrated. After the pre reformer, the gases can be preheated to temperatures around 650°C. In general, the pre-reformer captures also all the sulphur and hence protects the sulphur-sensitive catalyst in the tubular reformer. The pre-reformer is generally a fixed bed reactor operating under adiabatic conditions without heat injection to maintain the reaction temperature.

2. Autothermal reforming (ATR) uses oxygen and eventually steam and carbon dioxide to partially oxidize (internal combustion) the hydrocarbons:

CH₄+ 0.5 O₂ 2 H₂+ CO partial oxidation, exothermic, DH_G= 519 kJ/mol

2 CH₄ + 0.5 O₂ + CO₂ 4 H2 + 3 CO autothermal reforming, DH_G= 272 kJ/mol

2 CH₄ + 0.5 O₂ + H₂O +± 5 H2 + 2 CO autothermal reforming, DH_G= 313 kJ/mol

By adding steam or carbon dioxide the hydrogen to carbon monoxide ratio can be controlled according to the above-reported reactions. Autothermal reforming is essentially exothermic (extend depending on the amount of added steam or carbon dioxide) and can be operated in a single reactor vessel as no heat has to be injected into the reactor to maintain the appropriate reaction temperature.

Industrially steam reforming and autothermal reforming or partial oxidation can be applied individually but can also be combined. An endothermal steam tubular reformer can be operated at partial conversion, adding oxygen or air to the effluent that is subsequently sent to an exothermal autothermal reformer. Such configurations allow to reach very high conversion (methane slip) and reduce heat transfer equipment but reduce the hydrogen to carbon monoxide ratio. In the case of secondary reforming air is used to supply the needed nitrogen for ammonia synthesis. In the autothermal reforming, the added oxygen is converted by combustion and since the combustion reaction is exothermic, the temperature in the ATR is raised to about 1000 to 1050°C. The sensible heat in such reaction effluent of an autothermal reformer can be used to heat a heat-exchanger reformer (often called gas-heated reformer) by convective heat transfer. Such heat-exchanger (shell and tube exchanger or dual tube exchanger) reformer reactors are generally placed between a steam tubular reformer or pre-former and the autothermal reformer.

The autothermal reforming stage may be conducted with air (21 vol % oxygen) or with enriched air, i.e. a gas containing 30 to 70 vol % O2, more preferably 40 to 50 vol % C>2 to produce ammonia synthesis gas. When producing synthesis gas for hydrogen or methanol production, the autothermal reforming stage may be conducted with a gas containing at least 70 vol % oxygen, preferably nearly 100 vol % oxygen. The obtained syngas is used as a feedstock gas for multiple processes and can be converting into ammonia, methanol or higher alcohols, DME, into hydrocarbons (paraffins and olefins) by Fischer-Tropsch synthesis, or hydrogen. The use of syngas for the production of hydrogen is the primary commercial application of the SMR process. Hydrogen production incorporates several subsystems: i) feed pre-treatment, ii) reforming and heat recovery (including the steam system), iii) carbon monoxide conversion (water gas shift reaction), and iv) hydrogen purification (typically hydrogen pressure swing adsorption).

Alternatively, reforming of methane could be performed with hydrogen sulphide (H2S) which is frequently naturally present in gas reservoirs:

CH4 + 2 H2S CS2 + 4 H2 Thio-Reforming, endothermic, DH_G= -232 kJ/mol

The opportunity for methane reforming with hydrogen sulphide has been addressed in the patent documents: W02016001554A1, US20170158631A1, WO2017062799A1 and academic publications: A.L. Martinez-Salazar et al, Int. J. Hydr. Energy, 48, 2015, 17272- 17283. Typical catalysts used for the reaction are Pt/AhCh (0.5 wt.%), C^Ch/AhOs and PtRh, and reaction temperatures are in the range 700-1100°C, which would demand efficient heat management.

Formation of coke is the main issue of the process as forming carbon disulphide could polymerize at elevated temperatures to give so-called Brickman’s black, deactivating the catalyst. To mitigate coke formation, a large excess of hydrogen sulphide was used in listed disclosures, i.e. H2S/CH4 molar ratio of up to 12.

It is clear for one skilled in the art that implementation of such feed composition into the process is not favoured as circulation of tremendous amounts of hydrogen sulphide will cause high energy consumptions.

One should mention that the said thio-reforming has a big advantage relative to the traditional SMR due to the high flexibility of reaction feedstock. This means that any COx, water, and S- impurities are accepted by the reaction medium. So, the process is well adapted to the complex reaction medium and provides a significant saving in terms of energy and investments. In case if the oxygenates are present in the feedstock, the resulted product could be called sour synthesis gas, i.e. a mixture of CO, CS2 and H2.

One should mention that in contrast to the conventional SMR, the thio-reforming does not require a pre-reformer reactor with a very particular catalyst with a shorter lifetime versus the conventional SMR catalyst. This is possible due to a significant sulphur presence and mitigation of the coking. So, the presence of heavier hydrocarbons is not detrimental to the process.

The disclosure of GB1012284 relates to a process for the electrothermic production of carbon disulphide from gas-containing hydrogen sulphide and at least one gaseous hydrocarbon on a fluidized bed of coke particles at a temperature ranging between 900°C and 1500°C.

The present disclosure aims to provide a large-scale solution to one or more of the problems encountered in the prior art that is suitable for application in the industry, such as the chemical industry. The present disclosure aims to contribute to the replacement of the use of fossil carbon-based fuels heating devices in fluidized bed reactors. The present disclosure provides a solution to conduct endothermic reforming of light hydrocarbons with hydrogen sulphide into a mixture of hydrogen and carbon disulphide.

Summary

According to a first aspect, the disclosure provides for a process to perform an endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide (H2S) to produce carbon disulphide (CS2) and hydrogen (H2), said process is remarkable in that it comprises the steps of: a) providing at least one fluidized bed reactor comprising at least two electrodes, a bed comprising particles and optionally a solid discharge system; b) putting the particles of the bed, in a fluidized state by passing upwardly through the said bed a fluid stream, to obtain a fluidized bed; c) heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the endothermic thio-reforming reaction; d) obtaining a reactor effluent comprising hydrogen (H2), carbon disulphide (CS2), unconverted hydrogen sulphide (H2S) and hydrocarbons, and optionally sulfur (Ss) and/or methanethiol (CH₃SH); wherein the particles of the bed comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles, have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower- valent cations and/or any mixture thereof; and wherein the step (c) of heating the fluidized bed is performed by passing an electric current through the fluidized bed.

Surprisingly, it has been found that the use of electrically conductive particles such as silicon carbide, mixed oxides and/or mixed sulphides, said mixed oxides and/or said mixed sulphides being an ionic or mixed conductor, namely being doped with one or more lower-valent cations, in one or more fluidized bed reactors which are electrified allows maintaining a temperature sufficient to carry out an endothermic thio-reforming reaction requesting high-temperature condition such as temperature reaction ranging from 500°C to 1200°C without the need of any external heating device. The use of at least 10 wt.% of electrically conductive particles in the particles of the bed allows minimizing the loss of heat when a voltage is applied. Thanks to the Joule effect, most, if not all, the electrical energy is transformed into heat that is used for the heating of the reactor medium.

It is preferred that the at least one fluidized bed reactor comprising at least two electrodes and a bed comprising particles is devoid of packing.

For example, the fluid stream provided in step (b) comprises a mixture of hydrocarbon feedstock and hydrogen sulphide. The fluid stream may be a gaseous stream and/or a vaporized stream.

With preference, the fluid stream provided in step (b) further comprises carbon oxides (i.e. a mixture of carbon dioxide and/or carbon monoxide). In this case, the reactor effluent obtained at step (d) comprises hydrogen, carbon disulphide and unconverted carbon oxides, hydrogen sulphide and hydrocarbons, and optionally sulphur and/or methanethiol. In this case, the process advantageously comprises the step (e) of transforming said reactor effluent into thiol- derivative of said hydrocarbons and/or the step (f) of transforming said reactor effluent into higher hydrocarbons.

In a preferred embodiment, the volumetric heat generation rate is greater than 0.1 MW/m³ of fluidized bed, more preferably greater than 1 MW/m³, in particular, greater than 3 MW/m³.

In a preferred embodiment, at least one fluidized bed reactor is devoid of heating means; for example, at least one fluidized bed reactor is devoid of heating means located around or inside the vessel.

The solid particulate material (i.e. the particles) used in the at least one fluidized bed reactor comprises solid particulates having electrical conductivity allowing generating heat and catalytic particulate material to catalyse the thio-reforming reaction of hydrocarbons. The catalytic particulate material can also be electrically conductive and hence contribute to the generation of heat for the endothermal process.

The electrically conductive particles of the bed

For example, the content of electrically conductive particles based on the total weight of the particles of the bed is ranging from 10 wt.% to 100 wt.%; preferably, from 15 wt.% to 95 wt.%, more preferably from 20 wt.% to 90 wt.%, even more preferably from 25 wt.% to 80 wt.% and most preferably from 30 wt.% to 75 wt.%. In the case where the content of electrically conductive particles based on the total weight of the particles of the bed is 100 wt.%, at least a part of said electrically conductive particles are also catalytic particles.

For example, the content of electrically conductive particles based on the total weight of the particles of the bed 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.%.

For example, the electrically conductive particles have a resistivity ranging from 0.005 to 400 Ohm. cm at 800°C, preferably ranging from 0.01 to 300 Ohm. cm at 800°C; more preferably ranging from 0.05 to 150 Ohm. cm at 800°C and most preferably ranging from 0.1 to 100 Ohm. cm at 800°C.

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

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

The selection of the content of electrically conductive particles based on the total weight of the bed and of the electrically conductive particles of a given resistivity influence the temperature reached by the fluidized bed. Thus, in case the targeted temperature is not attained, the person skilled in the art may increase the density of the particles bed, the content of electrically conductive particles based on the total weight of the bed and/or select electrically conductive particles with a lower resistivity to increase the temperature reached by the fluidized bed.

For example, the density of the solid particles in the bed is expressed as the void fraction. Void fraction or bed porosity is the volume of voids between the particles divided by the total volume of the bed. At the incipient fluidisation velocity, the void fraction is typically between 0.4 and 0.5. The void fraction can increase up to 0.98 in fast fluidised beds with lower values at the bottom of about 0.5 and higher than 0.9 at the top of the bed. The void fraction can be controlled by the linear velocity of the fluidising gas and can be decreased by recycling solid particles that are recovered at the top and send back to the bottom of the fluidized bed, which compensates for the entrainment of solid particles out of the bed.

The void fraction VF is defined as the volume fraction of voids in a bed of particles and is determined according to the following equation:

Vt-Vp

VF = (1)

Vt wherein Vt is the total volume of the bed and is determined by

Vt = AH (2) wherein A is the cross-sectional area of the fluidized bed and H is the height of the fluidized bed; and wherein Vp is the total volume of particles within the fluidized bed.

For example, the void fraction of the bed is ranging from 0.5 to 0.8; preferably ranging from 0.5 to 0.7, more preferably from 0.5 to 0.6. To increase the density of the particle bed, the void fraction is to be reduced.

For example, the particles of the bed have an average particle size ranging from 5 to 300 pm as determined by sieving according to ASTM D4513-11, preferably ranging from 10 to 200 pm and more preferably ranging from 20 to 200 pm or from 30 to 150 pm. For example, the electrically conductive particles of the bed have an average particle size ranging from 5 to 300 pm as determined by sieving according to ASTM D4513-11 , preferably ranging from 10 to 200 pm and more preferably ranging from 20 pm or 200 pm or from 30 to 150 pm.

In an embodiment, from 50 wt.% to 100 wt.% of the electrically conductive particles of the bed based on the total weight of the electrically conductive particles of the bed are one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof; preferably, from 60 wt.% to 100 wt.%; more preferably from 70 wt.% to 100 wt.%; even more preferably from 80 wt.% to 100 wt.% and most preferably from 90 wt.% to 100 wt.%.

For example, the electrically conductive particles of the bed are or comprise one or more selected from one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, one or more mixed sulphides being doped with one or more lower-valent cations, and/or any mixture thereof; with preference in a content of from 50 wt.% to 100 wt.% based on the total weight of the electrically conductive particles of the bed; preferably, from 60 wt.% to 100 wt.%; more preferably from 70 wt.% to 100 wt.%; even more preferably from 80 wt.% to 100 wt.% and most preferably from 90 wt.% to 100 wt.%.

As an alternative, the electrically conductive particles of the bed comprise one or more particles selected from one or more metallic alloys, one or more non-metallic resistors, provided that the non-metallic resistor is not silicon carbide, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations and/or one or more and/or mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof; with preference in a content of from 50 wt.% to 100 wt.% based on the total weight of the electrically conductive particles of the bed; preferably, from 60 wt.% to 100 wt.%; more preferably from 70 wt.% to 100 wt.%; even more preferably from 80 wt.% to 100 wt.% and most preferably from 90 wt.% to 100 wt.%.

For example, the electrically conductive particles of the bed are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more mixed oxides being doped with one or more lower-valent cations, one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof; with preference in a content of from 50 wt.% to 100 wt.% based on the total weight of the electrically conductive particles of the bed; preferably, from 60 wt.% to 100 wt.%; more preferably from 70 wt.% to 100 wt.%; even more preferably from 80 wt.% to 100 wt.% and most preferably from 90 wt.% to 100 wt.%. For example, the electrically conductive particles of the bed are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more mixed oxides being doped with one or more lower-valent cations, one or more mixed sulphides being doped with one or more lower-valent cations, and/or any mixture thereof; with preference in a content of from 50 wt.% to 100 wt.% based on the total weight of the electrically conductive particles of the bed; preferably, from 60 wt.% to 100 wt.%; more preferably from 70 wt.% to 100 wt.%; even more preferably from 80 wt.% to 100 wt.% and most preferably from 90 wt.% to 100 wt.%.

For example, said one or more metallic alloys are selected from Ni-Cr, Fe-Ni-Cr, Fe-Ni-AI or a mixture thereof. With preference, when said metallic alloy comprises at least chromium, the chromium content is at least 15 mol.% of the total molar content of said metallic alloy comprising at least chromium, more preferably at least 20 mol.%, even more preferably at least 25 mol.%, most preferably at least 30 mol.%. Advantageously yet, the iron content in the metallic alloys is at most 2.0% based on the total molar content of said metallic alloy, preferably at most 1.5 mol.%, more preferably at most 1.0 mol.%, even more preferably at most 0.5 mol.%.

For example, a non-metallic resistor is silicon carbide (SiC), molybdenum disilicide (MoSh), nickel silicide (NiSi), sodium silicide (Na2Si), magnesium silicide (Mg2Si), platinum silicide (PtSi), titanium silicide (TiSh), tungsten silicide (WSh) or a mixture thereof, preferably silicon carbide. In an alternative, said non-metallic resistors particles are selected from molybdenum disilicide (MoSh), nickel silicide (NiSi), sodium silicide (Na2Si), magnesium silicide (Mg2Si), platinum silicide (PtSi), titanium silicide (TiSh), tungsten silicide (WSh) or a mixture thereof. For example, the non-metallic resistors particles are devoid of silicon carbide (SiC).

For example, said one or more metallic carbides are selected from iron carbide (FesC), molybdenum carbide (such as a mixture of MoC and M02C).

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

For example, said one or more metallic phosphides are selected from copper phosphide (CU₃P), indium phosphide (InP), gallium phosphide (GaP), sodium phosphide NasP), aluminium phosphide (AIP), zinc phosphide (Zn3P2) and/or calcium phosphide (Ca3P2).

For example, said one or more superionic conductors are selected from LiAISiCU, LiioGeP2Si2, Li3.6Sio_.6Po.4O4, sodium superionic conductors (NaSICON), such as Na3Zr2PSi20i2, or sodium beta alumina, such as NaAlnOi7, Nai.6Aln0i7.3, and/or Nai .761 — io - 38^^l 1 o - 62017.

For example, said one or more phosphate electrolytes are selected from UPO₄ or LaPCU.

For example, said one or more mixed oxides are ionic or mixed conductors being doped with one or more lower-valent cations. Advantageously, said mixed oxides are doped with one or more lower-valent cations, and are selected from oxides having a cubic fluorite structure, perovskite, pyrochlore.

For example, said one or more mixed sulphides are ionic or mixed conductors being doped with one or more lower-valent cations.

For example, the electrically conductive particles of the bed are or comprise silicon carbide.

For example, the electrically conductive particles of the bed comprise a mixture of a non- metallic resistor being silicon carbide and electrically conductive particles different from said silicon carbide. The presence of electrically conductive particles different from said silicon carbide in the bed is optional. It can be present as a starting material for heating the bed since it was found that the resistivity of silicon carbide at room temperature is too high to start heating the bed. Alternatively to the presence of electrically conductive particles different from silicon carbide, it is possible to provide heat to the reactor for a defined time to start the reaction.

For example, the silicon carbide is selected from sintered silicon carbide, nitride-bounded silicon carbide, recrystallised silicon carbide, reaction bonded silicon carbide and any mixture thereof. The type of silicon carbide material is selected according to the required heating power necessary for supplying the reaction heat.

For example, the particles of the bed comprise a mixture of a non-metallic resistor being silicon carbide and electrically conductive particles different from said silicon carbide and the particles of the bed comprises from 10 wt.% to 99 wt.% of silicon carbide based on the total weight of the particles of the bed; preferably, from 15 wt.% to 95 wt.%, more preferably from 20 wt.% to 90 wt.%, even more preferably from 25 wt.% to 80 wt.% and most preferably from 30 wt.% to 75 wt.%.

For example, the electrically conductive particles of the bed comprise a mixture of a non- metallic resistor being silicon carbide and electrically conductive particles different from said silicon carbide, said electrically conductive particles different from said silicon carbide are one or more mixed oxides being doped with one or more lower-valent cations and/or one or more mixed sulphides being doped with one or more lower-valent cations. For example, the electrically conductive particles of the bed comprise one or more mixed oxides being ionic conductor, namely being doped with one or more lower-valent cations; with preference, the mixed oxides being doped with one or more lower-valent cations are selected from:

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

- one or more ABCh-perovskites with A and B tri-valent cations, being at least partially substituted in A position with one or more lower-valent cations, preferentially selected from Ca, Sr, or Mg, and comprising at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe and/or a mixture thereof in B position; and/or

- one or more AB0₃-perovskites with A bivalent cation and B tetra-valent cation, being at least partially substituted with one or more lower-valent cations, preferentially selected from Mg, Sc, Y, Nd or Yb in the B position or with a mixture of different B elements in the B position; and/or

- one or more AaBaOypyrochlores with A trivalent cation and B tetra-valent cation being at least partially substituted in A position with one or more lower-valent cations, preferentially selected from Ca or Mg, and comprising at least one of Sn, Zr and Ti in B position.

Examples of one or more mixed sulphides are

- one or more sulphides having a cubic fluorite structure being at least partially substituted with one or more lower-valent cations, preferentially selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and/or

- one or more ABS₃ structures with A and B tri-valent cations being at least partially substituted in A position with one or more lower-valent cations, preferably selected from Ca, Sr, or Mg, and comprising at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe and/or a mixture thereof in B position; and/or

- one or more ABS₃ structures with A bi-valent cation and B tetra-valent cation, being at least partially substituted with one or more lower-valent cations, preferably selected from Mg, Sc, Y, Nd or Yb in the B position or with a mixture of different B elements in the B position; and/or

- one or more A2B2S7 structures with A tri-valent cation and B tetra-valent cation, being at least partially substituted in A position with one or more lower-valent cations, preferably selected from Ca or Mg, and comprising at least one of Sn, Zr and Ti in B position. With preference, 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 between 1 and 15 atom% based on the total number of atoms present in the one or more oxides having a cubic fluorite structure, preferably between 3 and 12 atom%, more preferably between 5 and 10 atom%.

Wth preference, the degree of substitution in the one or more mixed oxides doped with one or more lower-valent cations is between 1 and 50 atom % based on the total number of atoms present in the one or more ABCh-perovskites with A and B tri-valent cations, in the one or more ABCh-perovskites with A bivalent cation and B tetra-valent cation or in the one or more A B C> -pyrochlores with A trivalent cation and B tetra-valent cation respectively, preferably between 3 and 20 atom %, more preferably between 5 and 15 atom%.

Wth preference, the degree of substitution in the one or more mixed sulphides doped with one or more lower-valent cations and having a cubic fluorite structure is between 1 and 15 atom% based on the total number of atoms present in the one or more oxides having a cubic fluorite structure, preferably between 3 and 12 atom%, more preferably between 5 and 10 atom%.

Wth preference, the degree of substitution in the one or more mixed sulphides doped with one or more lower-valent cations is between 1 and 50 atom % based on the total number of atoms present in the one or more ABS₃ structures with A and B tri-valent cations, in the one or more ABS₃ structures with A bivalent cation and B tetra-valent cation or in the one or more A2B2S7 structures with A trivalent cation and B tetra-valent cation respectively, preferably between 3 and 20 atom%, more preferably between 5 and 15 atom%.

For example, the electrically conductive particles of the bed comprise one or more metallic alloys; with preference, one or more metallic alloys are selected from Ni-Cr, Fe-Ni-Cr, Fe-Ni- Al or a mixture thereof.

Wth preference, when said metallic alloy comprises at least chromium, the chromium content is at least 15 mol.% of the total molar content of said metallic alloy comprising at least chromium, more preferably at least 20 mol.%, even more preferably at least 25 mol.%, most preferably at least 30 mol.%. Advantageously yet, the iron content in the metallic alloys is at most 2.0% based on the total molar content of said metallic alloy, preferably at most 1.5 mol.%, more preferably at most 1.0 mol.%, even more preferably at most 0.5 mol.%.

In the case where said electrically conductive particles are different from said silicon carbide particles, they are particles are selected from non-metallic resistors, said non-metallic resistor is preferably molybdenum disilicide (MoSh). The particles of a catalytic composition

For example, the content of the particles of a catalytic composition based on the total weight of the particles of the bed is ranging from 30 wt.% to 100 wt.%; preferably from 32 wt.% to 95 wt.%, more preferably from 35 wt.% to 90 wt.%, even more preferably from 37 wt.% to 85 wt.%, most preferably from 40 wt.% to 80 wt.%, even most preferably from 45 wt.% to 75 wt.% or from 50 wt.% to 70 wt.%. In the case where the content of the particles of a catalytic composition based on the total weight of the particles of the bed is 100 wt.%, said particles of a catalytic composition are also electrically conductive particles.

For example, the particles of a catalytic composition have an average particle size ranging from 5 to 300 pm as determined by sieving according to ASTM D4513-11, preferably ranging from 10 to 200 pm and more preferably ranging from 20 to 200 pm, or from 30 to 150 pm.

For example, the catalytic composition comprises one or more metals. With preference, said one or more metals are selected from Ni, Ga, Cu, Fe, Co, Mo, Pt, Pd, Rh, Ru and/or Au, more preferably from Ni.

For example, the catalytic composition comprises one or more transition metals in a content ranging between 0.1 and 60.0 wt.% of the total weight of said catalytic composition; preferably between 0.5 and 55.0 wt.%, more preferably between 1.0 and 50.0 wt.%, even more preferably between 3.0 and 45.0 wt.%, most preferably between 5.0 and 40.0 wt.%, even most preferably between 10.0 and 35.0 wt.%.

Wth preference, the catalytic composition comprises a catalytic support.

Advantageously, said catalytic support is the electrically conductive particles; with preference, electrically conductive particles different from said silicon carbide. This allows intimate contact between the catalytic active material and the electrically conductive material.

Advantageously yet, said catalytic support is selected from AI₂O₃, T1O₂, ZrC>2, HfC>2, La₂C>₃, CeC>2, AI₂O₃ doped with silica, preferably from AI₂O₃.

Advantageously, said catalytic composition is pre-treated in an H2S stream at a temperature of at least 300°C before loading into the reactor.

In an embodiment, the catalytic composition comprises transition metals supported on AI₂O₃.

In an embodiment, the catalytic composition comprises noble metals supported on AI₂O₃. In an embodiment, the catalytic composition comprises metal sulphides, preferably supported on AI2O3.

In an embodiment, the catalytic composition comprises metal carbides.

In an embodiment, the catalytic composition comprises metal nitrides.

In an embodiment, the catalytic composition comprises metal silicides.

The endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide

For example, the endothermic thio-reforming reaction of hydrocarbons is conducted at a temperature ranging between 500°C and 1200°C, preferably ranging from 550°C and 1150°C, more preferably from 600°C to 1100°C, more preferably from 650°C to 1050°C, even more preferably from 700°C to 1000°C, and or from 800°C to 950°C.

For example, the endothermic thio-reforming reaction of hydrocarbons is performed at a pressure ranging between 0. 1 MPa and 10 MPa, preferably between 0.5 MPa and 8.0 MPa, more preferably between 1.0 MPa and 7.0 MPa, even more preferably between 1.5 MPa and 6.5 MPa.

For example, the FhS/number of carbon atoms in the hydrocarbons feedstock molar ratio is ranging between 0.15 and 5.0, preferably between 0.20 and 4.5, more preferably between 0.3 and 4.0, even more preferably between 0.5 and 3.5, most preferably between 1.0 and 3.0.

In an embodiment, said process comprises a step of pre-heating with a gaseous stream said one or more fluidized bed reactor before conducting said endothermic thio-reforming reaction of hydrocarbons in said one or more fluidized bed reactors; with preference, said gaseous stream is a stream of diluent gas being inert gas and/or has a temperature comprised between 500°C and 1200°C. The said embodiment is of interest when the electrically conductive particles of the bed have too high resistivity at room temperature to start the electro-heating of the bed.

For example, the endothermic thio-reforming reaction of hydrocarbons is performed at a weight hourly space velocity (defined as the ratio of mass flow of reaction stream to the mass of solid particulate material in the fluidized bed) of said reaction stream comprised between 0.1 h ¹ and 100 h ¹, preferably comprised between 1.0 h ¹ and 50 h ¹, more preferably comprised between 1.5 h ¹ and 10 h ¹, even more preferably comprised between 2.0 h ¹ and 6.0 h ¹. The weight hourly space velocity is defined as the ratio of mass flow of the reaction stream to the mass of solid particulate material in the fluidized bed. For example, the said at least two electrodes are made in electrically conductive material; with preference, said at least two electrodes are made in graphite; or in nickel-chromium alloys; or in nickel-chromium-iron alloys.

In a preferred embodiment, the outlet temperature of the reactor may range from 800 to 1200°C, preferably from 820 to 1100°C, more preferably from 830 to 950°C, more preferably from 840°C to 900°C.

In a preferred embodiment, the residence time of the hydrocarbon feedstock in the fluidised bed section of the reactor where the temperature is between 500 and 1200°C, may range from 0.005 to 0.5 seconds, preferably from 0.01 to 0.4 seconds.

In a preferred embodiment said hydrocarbon feedstock is comprising at least 50 wt.% of methane based on the total weight of said hydrocarbon feedstock, preferably at least 80 wt.%, most preferably at least 90 wt.%. Optionally, said hydrocarbon feedstock comprises C2+ hydrocarbons and/or higher thiols (i.e. thiols having at least two carbon atoms).

With preference, the fluid stream provided in step (b) comprises one or more oxygenates selected from water (H₂O), carbonyl sulphide (COS), methanol (CH₃OH), dimethoxyethane (C₄H₁₀O₂, i.e. DME), and ethanol (C₂H₅OH). The fluid stream provided in step (b) can optionally comprise dimethyl sulphide (CH₃SCH₃), dimethyl disulphide (CH₃S-SCH₃), and/or inert gas, such as nitrogen, helium and/or argon.

For example, the fluid stream provided in step (b) is a gaseous fluid stream. The fluid stream may be a vaporized stream.

For example, the step of heating the fluidized bed is performed by passing an electric current of at most 300 V through the fluidized bed, preferably at most 200 V, more preferably at most 150 V, even more preferably at most 120 V, most preferably at most 100 V, even most preferably at most 90 V.

For example, wherein the at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone and wherein the fluid stream provided in step b) is provided to the heating zone and comprises diluent gases and/or hydrogen sulphide, the step c) of heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the thio- reforming reaction of hydrocarbons comprises the following sub-steps: heating the fluidized bed to a temperature ranging from 500°C to 1200°C by passing an electric current through the heating zone of the at least one fluidized bed, transporting the heated particles from the heating zone to the reaction zone, in the reaction zone, putting the heated particles in a fluidized state by passing upwardly through the said bed of the reaction zone a fluid stream comprising a mixture of hydrocarbon feedstock, hydrogen sulphide and optional diluent gases to obtain a fluidized bed and to conduct the thio-reforming reaction on the hydrocarbon feedstock, optionally, recovering the particles from the reaction zone and recycling them to the heating zone.

Step c) provides that the thio-reforming reaction is performed on a mixture of hydrocarbon feedstock and hydrogen sulphide which implies that a mixture of hydrocarbons feedstock and hydrogen sulphide is provided.

For example, wherein the heating zone and the reaction zone are mixed (i.e. the same zone); the fluid stream provided in step b) comprises a mixture of hydrocarbons feedstock and hydrogen sulphide. The fluid stream may be a gaseous stream and/or a vaporized stream.

For example, wherein the heating zone and the reaction zone are separated zones, the fluid stream provided in step b) to the heating zone is devoid of a hydrocarbon feedstock. For example, wherein the process comprises providing at least one fluidized bed reactor being a heating zone and at least one fluidized bed reactor is a reaction zone, the fluid stream provided in step b) to the heating zone is devoid of a hydrocarbons feedstock and the fluid stream provided in step b) to the reaction zone comprises a mixture of a hydrocarbons feedstock and hydrogen sulphide.

Thus, depending on the configuration, the fluid stream comprises a mixture of hydrocarbons feedstock and hydrogen sulphide; and/or diluent gases.

It is understood that the mixture of hydrocarbon feedstock and hydrogen sulphide is provided to the reaction zone and that when the heating zone is separated from the reaction zone, such a mixture of hydrocarbon feedstock and hydrogen sulphide is not provided to the heating zone.

The installation

According to a second aspect, the disclosure provides an installation to perform an endothermic reforming reaction on hydrocarbons with hydrogen sulphide to produce carbon disulphide and hydrogen, according to the first aspect, said installation comprising at least one fluidized bed reactor comprising: at least two electrodes; with preference one electrode is a submerged central electrode or two electrodes are submerged electrodes; optionally a solid discharge system, a reactor vessel; one or more fluid nozzles for the introduction of a fluidizing gas and/or of a reaction stream within the reactor; and a bed comprising particles; the installation is remarkable in that the particles of the bed comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof.

Advantageously, at least one fluidized bed reactor is devoid of heating means. For example, at least one fluidized bed reactor is devoid of heating means located around or inside the reactor vessel. For example, all the fluidized bed reactors are devoid of heating means. For example, at least one fluidized bed reactor is devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof. For example, all the fluidized bed reactors are devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof.

For example, at least one reactor vessel has an inner diameter of at least 100 cm, preferably at least 200 cm, more preferably at least 300 cm.

With preference, the reactor vessel comprises a reactor wall made of materials that are corrosion-resistant materials and advantageously said reactor wall materials comprise nickel (Ni), SiAION ceramics, yttria-stabilized zirconia (YSZ), tetragonal polycrystalline zirconia (TZP) and/or tetragonal zirconia polycrystal (TPZ).

For example, the at least one fluidized bed reactor comprises a heating zone and a reaction zone, one or more fluid nozzles to provide a mixture of hydrocarbon feedstock and hydrogen sulphide to the reaction zone, and the installation is arranged or comprises means to transport the particles from the heating zone to the reaction zone and optional means to transport the particles from the reaction zone back to the heating zone. This configuration is remarkable in that a given particle bed is common to at least two fluidized bed reactors. The common bed particle is distributed between at least two reactors and continuously moving from one reactor to another one.

For example, the installation comprises at least two fluidized bed reactors connected one to each other wherein at least one of said at least two fluidized bed reactors is the heating zone and at least another of said at least two fluidized bed reactors is the reaction zone. With preference, the installation comprises one or more fluid nozzles arranged to inject a mixture of hydrocarbon feedstock and hydrogen sulphide to the at least one fluidized bed reactor being the reaction zone.

For example, the at least one fluidized bed reactor is a single one fluidized bed reactor wherein the heating zone is the bottom part of the fluidized bed reactor while the reaction zone is the top part of the fluidised bed reactor. Wth preference, the installation comprises one or more fluid nozzles to inject a mixture of hydrocarbon feedstock and hydrogen sulphide between the two zones. The diameter of the heating zone and reaction zone can be different to accomplish optimum conditions for heating in the bottom zone and optimum conditions for hydrogen sulphide in the top zone. Particles can move from the heating zone to the reaction zone by entrainment and the other way around from the reaction zone back to the heating zone by gravity. Optionally, particles can be collected from the upper heating zone and transferred by a separate transfer line back to the bottom heating zone.

For example, the at least one fluidized bed comprises at least two lateral zones being an outer zone and an inner zone wherein the outer zone is surrounding the inner zone, with the outer zone being the heating zone and the inner zone being the reaction zone. In a less preferred configuration, the outer zone is the reaction zone and the inner zone is the heating zone. Wth preference, the installation comprises one or more fluid nozzles to inject a hydrocarbon feedstock in the reaction zone. Wth preference, one of the electrodes is the reactor vessel or the gas distributor and/or said at least two electrodes are made in graphite or in nickel- chromium alloys or in nickel-chromium-iron alloys.

For example, the at least one fluidized bed reactor is devoid of packing. In an embodiment, from 50 wt.% to 100 wt.% of the electrically conductive particles of the bed based on the total weight of the electrically conductive particles of the bed are one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof; preferably, from 60 wt.% to 100 wt.%; more preferably from 70 wt.% to 100 wt.%; even more preferably from 80 wt.% to 100 wt.% and most preferably from 90 wt.% to 100 wt.%.

The use of a particle bed

According to a third aspect, the disclosure provides the use of a bed comprising particles in at least one fluidized bed reactor to perform a process of thio-reforming reaction of hydrocarbons with hydrogen sulphide according to the first aspect, the use is remarkable in that the particles of the bed comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof.

For example, the at least one fluidized bed reactor comprising at least two electrodes and a bed comprising particles is devoid of packing.

For example, the use comprises heating the bed comprising particles to a temperature ranging from 500°C to 1200°C in a first reactor, transporting the heated particle bed from the first reactor to a second reactor and providing a mixture of hydrocarbon feedstock and hydrogen sulphide to the second reactor; with preference, at least the second reactor is a fluidized bed reactor and/or at least the second reactor is devoid of heating means; more preferably, the first reactor and the second reactor are fluidized bed reactors and/or the first and the second reactor are devoid of heating means. For example, at least the second reactor is devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof. For example, the first and the second reactors are devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof.

The use of an installation with at least one fluidized bed reactor

According to a fourth aspect, the disclosure provides the use of an installation comprising at least one fluidized bed reactor to perform a thio-reforming reaction, remarkable in that the installation is according to the second aspect. With preference, the use of an installation at least one fluidized bed reactor to perform a thio-reforming reaction in a process according to the first aspect.

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

Description of the figures

- Figure 1 illustrates an installation according to the prior art.

- Figure 2 illustrates an installation according to the disclosure with one reactor wherein the heating zone and reaction zone are the same.

- Figure 3 illustrates an installation according to the disclosure with one reactor wherein the heating zone and reaction zone are arranged one above the other.

- Figure 4 illustrates an installation according to the disclosure with one reactor wherein the heating zone and reaction zone are arranged one lateral to the other.

- Figure 5 illustrates an installation according to the disclosure with two reactors.

Detailed description

For the disclosure, the following definitions are given:

The terms "comprising", "comprises" and "comprised of" as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms "comprising”, "comprises" and "comprised of" also include the term “consisting of”. The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1 , 2, 3, 4, 5 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of endpoints also includes the recited endpoint values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

According to a first aspect, the disclosure provides for a process to perform an endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide (H2S) to produce carbon disulphide (CS2) and hydrogen (H2), said process is remarkable in that it comprises the steps of: a) providing at least one fluidized bed reactor comprising at least two electrodes, a bed comprising particles and optionally a solid discharge system; b) putting the particles of the bed in a fluidized state by passing upwardly through the said bed a fluid stream, to obtain a fluidized bed; c) heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the endothermic thio-reforming reaction; d) obtaining a reactor effluent containing hydrogen (H2), carbon disulphide (CS2), unconverted hydrogen sulphide (H2S) and hydrocarbons, and optionally sulfur (Ss) and/or methanethiol (CH₃SH); wherein the particles of the bed comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and wherein the step (c) of heating the fluidized bed is performed by passing an electric current through the fluidized bed.

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

For example, the fluid stream provided in step (b) comprises a fluidising gas and/or a reaction stream; with preference, the fluidizing gas is one or more diluent gases; and/or the reaction stream comprises a mixture of hydrocarbons feedstock and hydrogen sulphide.

For example, the fluid stream provided in step (b) comprises a mixture of hydrocarbons feedstock and hydrogen sulphide. With preference, the fluid stream provided in step (b) further comprises carbon oxides (i.e. a mixture of carbon dioxide and/or carbon monoxide) and water. In this case, the reactor effluent obtained at step (d) comprises hydrogen, carbon disulphide and unconverted carbon oxides, hydrogen sulphide and hydrocarbons, and optionally sulphur and/or methanethiol.

In a preferred embodiment said hydrocarbons feedstock comprises at least 50 wt.% of methane based on the total weight of said hydrocarbons feedstock, preferably at least 80 wt.%, most preferably at least 90 wt.%. Optionally, said hydrocarbons feedstock comprises at least one of the following: ethane, propane, butane, pentane, ethylene, propylene, butene, pentene, methanethiol, and ethanethiol. These hydrocarbons can be processed without pre reformer.

With preference, the fluid stream provided in step (b) comprises one or more oxygenates selected from carbonyl sulphide (COS), methanol (CH₃OH), dimethoxyethane (C₄H₁₀O₂, i.e. DME), and ethanol (C₂H₅OH). The fluid stream provided in step (b) can optionally comprises dimethyl sulphide (CH₃SCH₃) and/or dimethyl disulphide (CH₃S-SCH₃) and/or nitrogen.

The solid particulate material (i.e. the particles) in the fluidized bed reactor is typically supported by a porous plate, a perforated plate, a plate with nozzles or chimneys, known as a distributor. The fluid is then forced through the distributor up and travelling 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, known as a packed bed reactor. As the fluid velocity is increased, the particulate solids will reach a stage where the force of the fluid on the solids is enough to counterbalance the weight of the solid particulate material. This stage is known as incipient fluidization and occurs at this minimum fluidization velocity. Once this minimum velocity is surpassed, the contents of the reactor bed begin to expand and become fluidized. Depending on the operating conditions and properties of the solid phase various flow regimes can be observed in such reactors. The minimum fluidization velocity needed to achieve bed expansion depends upon the size, shape, porosity and density of the particles and the density and viscosity of the upflowing fluid. (P.R. Gunjal, V.V. Ranade, in Industrial Catalytic Processes for Fine and Specialty Chemicals, 2016).

Four different categories of fluidization based on the mean particle have been differentiated by Geldart that determine the fluidization regimes: type A, aeratable fluidization (medium size, medium-density particles which are easier to fluidize; Particles of typically 30-100 pm, density ~ 1500 kg/m³); type B, sand-like fluidization (heavier particles which are difficult to fluidize; Particles of typically 100-800 pm, density between 1500 and 4000 kg/m³); type C, cohesive fluidization (typical powder-like solid particle fluidization; Fine-size particles (~ 20 pm) with a dominance of intraparticle or cohesive forces); and type D, spoutable fluidization (large density and larger particle ~ 1-4 m , dense and spoutable).

Fluidization may be broadly classified into two regimes (Fluid Bed Technology in Materials Processing, 1999 by CRC Press): homogeneous fluidization and heterogeneous fluidization. In homogeneous or particulate fluidization, particles are fluidized uniformly without any distinct voids. In heterogeneous or bubbling fluidization, gas bubbles devoid of solids are distinctly observable. These voids behave like bubbles in gas-liquid flows and exchange gas with the surrounding homogeneous medium with a change in size and shape while rising in the medium. In particulate fluidization, the bed expands smoothly with substantial particle movement and the bed surface is well defined. Particulate fluidization is observed only for Geldart-A type particles. A bubbling fluidization regime is observed at much higher velocities than homogeneous fluidization, in which distinguishable gas bubbles grow from the distributor, may coalesce with other bubbles and eventually burst at the surface of the bed. These bubbles intensify the mixing of solids and gases and bubble sizes tend to increase further with a rise in fluidization velocity. A slugging regime is observed when the bubble diameter increases up to the reactor diameter. In a turbulent regime, bubbles grow and start breaking up with the expansion of the bed. Under these conditions, the top surface of the bed is no longer distinguishable. In fast fluidization or pneumatic fluidization, particles are transported out of the bed and need to be recycled back into the reactor. No distinct bed surface is observed.

Fluidized bed reactors have the following advantages:

Uniform Particle Mixing: Due to the intrinsic fluid-like behavior of the solid particulate material, fluidized beds do not experience poor mixing as in packed beds. The elimination of radial and axial concentration gradients also allows for better fluid-solid contact, which is essential for reaction efficiency and quality.

Uniform Temperature Gradients: Many chemical reactions require the addition or removal of heat. Local hot or cold spots within the reaction bed are avoided in a fluidized situation.

Ability to Operate Reactor Continuously: The fluidized bed nature of these reactors allows for the ability to continuously withdraw the products and introduce new reactants into the reaction vessel. On top of continuous operation of the chemical reactions, the fluidized bed allows also to continuously or at a given frequency withdraw solid material or add continuously or at a given frequency new fresh solid material thanks to the flowable solid particulate material. Heat can be produced by passing an electrical current through a conducting material that has sufficiently high resistivity (the resistor) to transform electricity into heat. Electrical resistivity (also called specific electrical resistance or volume resistivity, is an intrinsic property independent of shape and size) and its inverse, electrical conductivity, is a fundamental property of a material that quantifies how strongly it resists or conducts electric current (SI unit of electrical resistivity is the ohm-meter (W-m) and for conductivity Siemens per meter (S/m)).

When electricity is passed through a fixed bed of electrically conducting particulate solids, having a sufficient resistivity, the bed offers resistance to the flow of current; this resistance depends on many parameters, including the nature of the solid, the nature of the linkages among the particles within the bed, the bed voidage, the bed height, the electrode geometry, etc. If the same fixed bed is fluidized by passing gas, the resistance of the bed increases; the resistance offered by the conducting particles generates heat within the bed and can maintain the bed in isothermal conditions (termed an electrothermal fluidized bed or electrofluid reactor). In many high-temperature reactions, electrofluid reactors offer in situ heating during the reaction and are particularly useful for operating endothermic reactions and hence save energy because no external heating or transfer of heat is required.

It is a prerequisite that at least part of the solid particulate material is electrically conducting but non-conducting solid particulates can be mixed and still result in enough heat generation. Such non-conducting or very high resistivity solids can play a catalytic role in the chemical conversion. The characteristics of the bed material determine the resistance of an electrothermal fluidized bed furnace; as this is a charge resistor type of heat generation, the specific resistivity of the particles affects the bed resistance. The size, shape, composition, and size distribution of the particles also influence the magnitude of the bed resistance. Also, when the bed is fluidized, the voids generated between the particles increases the bed resistance. The total resistance of the bed is the sum of two components, e.g. the electrode contact-resistance (i.e., the resistance between the electrode and the bed) and the bed resistance. A large contact-resistance will cause extensive local heating in the vicinity of the electrode while the rest of the bed stays rather cool.

The following factors determine the contact-resistance: current density, fluidization velocity, type of bed material, electrode size and the type of material used for the electrodes. The electrode compositions can be advantageously metallic like iron, cast iron or other steel alloys, copper or a copper-based alloy, nickel or a nickel-based alloy or refractory like metal, intermetallics or an alloy of Zr, Hf, V, Nb, Ta, Cr, Mo, W or ceramic-like carbides, nitrides. The area of contact between the bed material and the electrodes can be adjusted, depending on the electrode submergence and the amount of particulate material in the fluidized bed. Hence, the electrical resistance and the power level can be manipulated by adjusting these variables. Advantageously, to prevent overheating of the electrodes compared to the fluidised bed, the resistivity of the electrode should be lower (and hence the joule heating) than of the particulate material of the fluidized bed. In a preferred embodiment, the electrodes can be cooled by passing a colder fluid inside or outside the electrodes. Such fluids can be any liquid that vaporises upon a heating, gas stream or can be a part of the colder feedstock that first cools the electrode before entering the fluidised bed.

Bed resistance can be predicted by the ohmic law. The mechanism of current transfer in fluidized beds is believed to occur through current flow along continuous chains of conducting particles at low operating voltages. At high voltages, a current transfer occurs through a combination of chains of conducting particles and arcing between the electrode and the bed as well as particle-to-particle arcing that might ionize the gas, thereby bringing down the bed resistance. Arcing inside the bed, in principle, is not desirable as it would lower the electrical and thermal efficiency. The gas velocity impacts strongly the bed resistance, a sharp increase in resistance from the settled bed onward when the gas flow rate is increased; a maximum occurred close to the incipient fluidization velocity, followed by a decrease at higher velocities. At gas flow rates sufficient to initiate slugging, the resistance again increased. Particle size and shape impact resistance as they influence the contacts points between particles. In general, the bed resistivity increases 2 to 5 times from a settled bed to the incipient fluidisation and 10 to 40 times from a settled bed to twice the incipient fluidisation velocity. Non or less- conducting particles can be added to conducting particles. If the conducting solid fraction is small, the resistivity of the bed would increase due to the breaking of the linkages in the chain of conducting solids between the electrodes. If the non-conducting solid fraction is finer in size, it would fill up the interstitial gaps or voidage of the larger conducting solids and hence increase the resistance of the bed.

In general, for a desired high heating power, a high current at a low voltage is preferred. The power source can be either AC or DC. Voltages applied in an electrothermal fluidized bed are typically below 100 V to reach enough heating power. The electrothermal fluidized bed can be controlled in the following three ways:

1. Adjusting the gas flow: Because the conductivity of the bed depends on the extent of voidage or gas bubbles inside the bed, any variation in the gas flow rate would change the power level; hence the temperature can be controlled by adjusting the fluidizing gas flow rate. The flow rate required for optimum performance corresponds to a velocity which equals or slightly exceeds the minimum fluidization velocity. 2. Adjusting the electrode submergence: The power level can also be controlled by varying the electrode immersion level inside the bed because the conductivity of the bed is dependent on the area of contact between the conducting particles and the electrode: the surface area of the electrode available for current flow increases with electrode submergence, leading to a reduction in overall resistance.

3. Adjusting the applied voltage: although changing the power level by using the first two methods is often more affordable or economical than increasing the applied voltage, however in electrothermal fluidized beds three variables are available to control the produced heating power.

The wall of the reactor is generally made of graphite, ceramics (like SiC), high-melting metals or alloys as it is versatile and compatible with many high-temperature reactions of industrial interest. The atmosphere for the reaction is often restricted to the neutral or the reducing type as an oxidising atmosphere can combust carbon materials or create a non-conducting metal oxide layer on top of metals or alloys. The wall and/or the distribution plate itself can act as an electrode for the reactor. The fluidized solids can be any high-melting-point, electrically conducting particles. The other electrodes, which is usually immersed in the bed, can also be graphite or a high-melting-point metal, intermetallics or alloys.

It may be advantaged to generate the required reaction heat by heating the conductive particles and/or catalyst particles in a separate zone of the reactor where little or substantially no feedstock hydrocarbons are present, but only diluent gases and/or hydrogen sulphide. The benefit is that the appropriate conditions of fluidization to generate heat by passing an electrical current through a bed of conductive particles can be optimized whereas the optimal reaction conditions during hydrocarbon transformation can be selected for the other zone of the reactor. Such conditions of optimal void fraction and linear velocity might be different for heating purposes and chemical transformation purposes.

In an embodiment of the present disclosure, the installation comprises of two zones arranged in series namely a first zone being a heating zone and a second zone being a reaction zone, where the conductive particles and catalyst particles are continuously moved or transported from the first zone to the second zone and vice versa. The first and second zones can be different parts of a fluidized bed or can be located in separate fluidized beds reactors connected to each other. In the said embodiment, the process to perform an endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide to produce carbon disulphide and hydrogen comprises the steps of: a) providing at least one fluidized bed reactor comprising at least two electrodes, a bed comprising particles and optionally a solid discharge system; b) putting the particles in a fluidized state by passing upwardly through the said bed a fluid stream, to obtain a fluidized bed; c) heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the endothermic thio-reforming reaction of a hydrocarbon feedstock in presence of hydrogen sulphide; and d) obtaining a reactor effluent containing hydrogen (H2), carbon disulphide (CS2), and unconverted hydrogen sulphide and hydrocarbons; and optionally sulfur and/or methanethiol; wherein the particles of the bed comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof, wherein the at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone and wherein the fluid stream provided in step b) is provided to the heating zone and comprises diluent gases and/or hydrogen sulphide and the step c) of heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the thio-reforming reaction of a hydrocarbon feedstock in presence of hydrogen sulphide comprises the following sub-steps: heating the fluidized bed to a temperature ranging from 500°C to 1200°C by passing an electric current through the heating zone of the at least one fluidized bed, transporting the heated particles from the heating zone to the reaction zone, in the reaction zone, putting the heated particles in a fluidized state by passing upwardly through the said bed of the reaction zone a fluid stream comprising a mixture of hydrocarbon feedstock, hydrogen sulphide and optional diluent gases to obtain a fluidized bed and to conduct the endothermic thio-reforming reaction on the hydrocarbon feedstock, optionally, recovering the particles from the reaction zone and recycling them to the heating zone. For example, the diluent gases can be one or more selected from hydrogen, carbon dioxide, nitrogen.

For example, the at least one fluidized bed reactor is at least two fluidized bed reactors connected one to each other wherein at least one of said at least two fluidized bed reactors is the heating zone and at least another of said at least two fluidized bed reactors is the reaction zone. With preference, the at least one fluidized bed reactor being the heating zone comprises gravitational or pneumatic transport means to transport the particles from the heating zone to the reaction zone and/or the installation comprises means arranged to inject a mixture of hydrocarbon feedstock and hydrogen sulphide to the at least one fluidized bed reactor being the reaction zone. The installation is devoid of means to inject a hydrocarbon feedstock to the at least one fluidized bed reactor being the heating zone.

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 while the reaction zone is the top part of the fluidised bed reactor. Wth preference, the installation comprises means to inject a mixture of hydrocarbon feedstock and hydrogen sulphide between the two zones.

Step c) provides that the thio-reforming reaction is performed on a mixture of hydrocarbon feedstock and hydrogen sulphide which implies that a mixture of hydrocarbon feedstock and hydrogen sulphide is provided. It is understood that the hydrocarbon feedstock is provided to the reaction zone and that when the heating zone is separated from the reaction zone then, with preference, no hydrocarbon feedstock is provided to the heating zone. When the heating zone and the reaction zone are mixed (i.e. the same zone); the fluid stream provided in step b) comprises a mixture of hydrocarbon feedstock and hydrogen sulphide. The fluid stream may be a gaseous stream and/or a vaporized stream.

It is a specific embodiment of the present disclosure that the distance between the heat sources, being the hot particulate material and the feedstock is significantly reduced because of the small size of the particulates and the mixing of the particulates in the vaporous fluidising stream, compared to steam reformer tubes having typically 5 to 25 cm internal diameter requiring large temperature gradients to concur the large distance that heat has to travel.

In a preferred embodiment, the volumetric heat generation rate is greater than 0.1 MW/m³ of fluidized bed, more preferably greater than 1 MW/m³, in particular, greater than 3 MW/m³. The bed comprising particles

According to the disclosure the particles of the bed comprises electrically conductive particles and catalytic particles. For example, the catalytic particles are electrically conductive. For example, the electrically conductive particles are a mixture of catalytic particle and non- catalytic particles.

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

For example, the content of electrically conductive particles based on the total weight of the bed 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.%.

For example, the content of electrically conductive particles based on the total weight of the bed is at most 75 wt.% based on the total weight of the particles of the bed; preferably, at most 80 wt.%, more preferably, at most 85 wt.%; even more preferably at most 90 wt.%, and most preferably at most 95 wt.% or at most 98 wt.% or is 100 wt.%. To achieve the required temperature necessary to carry out the thio-reforming reaction, at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C.

For example, the electrically conductive particles have a resistivity ranging from 0.005 to 400 Ohm. cm at 800°C, preferably ranging from 0.01 to 300 Ohm. cm at 800°C; more preferably ranging from 0.05 to 150 Ohm. cm at 800°C and most preferably ranging from 0.1 to 100 Ohm. cm at 800°C. For example, the electrically conductive particles have a resistivity of at least 0.005 Ohm. cm at 800°C; preferably of at least 0.01 Ohm. cm at 800°C, more preferably of at least 0.05 Ohm. cm at 800°C; even more preferably of at least 0.1 Ohm. cm at 800°C, and most preferably of at least 0.5 Ohm. cm at 800°C.

For example, the particles of the bed have an average particle size ranging from 5 to 300 pm as determined by sieving according to ASTM D4513-11 , preferably ranging from 10 to 200 pm and more preferably ranging from 20 to 200 pm or from 30 to 150 pm.

For example, the electrically conductive particles of the bed have an average particle size ranging from 5 to 300 pm as determined by sieving according to ASTM D4513-11 , preferably ranging from 10 to 200 pm and more preferably ranging from 20 to 200 pm, or from 30 to 150 pm, or from 40 to 120 pm.

For example, the particles of a catalytic composition have an average particle size ranging from 5 to 300 pm as determined by sieving according to ASTM D4513-11, preferably ranging from 10 to 200 pm and more preferably ranging from 20 to 200 pm or from 30 to 150 pm, or from 40 to 120 pm.

Determination by sieving according to ASTM D4513-11 is preferred. In case the particles have an average size of below 20 pm the determination of the average size can also be done by Laser Light Scattering according to ASTM D4464-15.

The electrical resistance is measured by a four-probe DC method using an ohmmeter. A densified power sample is shaped in a cylindrical pellet that is placed between the probe electrodes. Resistivity is determined from the measured resistance value, R, by applying the known expression p = R x A / L, where L is the distance between the probe electrodes typically a few millimetres and A the electrode area.

The solid particulate material can exhibit electronic, ionic or mixed electronic-ionic conductivity. The ionic bonding of many refractory compounds allows for ionic diffusion and correspondingly, under the influence of an electric field and appropriate temperature conditions, ionic conduction. The electrical conductivity, s, the proportionality constant between the current density j and the electric field E, is given by s = j / E = å Q x Z,q x m, where q is the carrier density (number=cm³), m, the mobility (c ²/Vs), and Z'q the charge (q=1.6 x 10¹⁹ C) of the ith charge carrier. The many orders of magnitude differences in s between metals, semiconductors and insulators generally result from differences in c rather than m. On the other hand, the higher conductivities of electronic versus ionic conductors are generally due to the much higher mobilities of electronic versus ionic species.

The most common materials that can be used for resistive heating can be subdivided into nine groups:

(1) Metallic alloys for temperatures up to 1200-1400°C,

(2) non-metallic resistors like silicon carbide (SiC), molybdenum disilicide (MoSh), nickel silicide (NiSi), sodium silicide (Na Si), magnesium silicide (Mg Si), platinum silicide (PtSi), titanium silicide (TiSh) and tungsten silicide (WSh) up to 1600-1900°C,

(3) several mixed oxides and/or mixed sulphides with variable temperature optima,

(4) graphite up to 2000°C,

(5) metallic carbides,

(6) transition metal nitrides,

(7) metallic phosphides,

(8) superionic conductors and

(9) phosphate electrolytes.

A first group of metallic alloys, for temperatures up to 1150-1250°C, is constituted by Ni-Cr alloys with low Fe content (0.5-2.0 %), preferably alloy Ni-Cr (80 % Ni, 20 % Cr) and (70 % Ni, 30 % Cr). Increasing the content of Cr increases the material resistance to oxidation at high temperatures. A second group of metallic alloys having three components are Fe-Ni-Cr alloys, with maximum operating temperature in an oxidizing atmosphere to 1050-1150°C but which can be conveniently used in reducing atmospheres or Fe-Cr-AI (chemical composition 15-30 % Cr, 2-6 % Al and Fe balance) protecting against corrosion by a surface layer of oxides of Cr and Al, in oxidizing atmospheres can be used up to 1300-1400°C. Silicon carbides can exhibit wide ranges of resistivity that can be controlled by the way they are synthesized and the presence of impurities like aluminium, iron, oxide, nitrogen or extra carbon or silicon resulting in non-stoichiometric silicon carbide. In general silicon carbide has a high resistivity at low temperature but has good resistivity in the range of 500 to 1200°C. In an alternative embodiment, the non-metallic resistor can be devoid of silicon carbide, and/or can comprise molybdenum disilicide (MoSh), nickel silicide (NiSi), sodium silicide (Na2Si), magnesium silicide (Mg2Si), platinum silicide (PtSi), titanium silicide (TiSh), tungsten silicide (WSh) or a mixture thereof.

Many mixed oxides and/or mixed sulphides being doped with one or more lower-valent cations, having in general too high resistivity at low temperature, become ionic or mixed conductors at high temperature. The following circumstances can make oxides sufficient conductors for heating purposes: ionic conduction in solids is described in terms of the creation and motion of atomic defects, notably vacancies and interstitials of which its creation and mobility is very positively dependent on temperature. Three mechanisms for ionic defect formation in oxides are known: (1) Thermally induced intrinsic ionic disorder (such as Schottky and Frenkel defect pairs resulting in non-stoichiometry), (2). Redox-induced defects and (3) Impurity-induced defects. The first two categories of defects are predicted from statistical thermodynamics and the latter form to satisfy electroneutrality. In the latter case, high charge carrier densities can be induced by substituting lower valent cations for the host cations. Mixed oxides and/or mixed sulphides with fluorite, pyrochlore or perovskite structure are very suitable for substitution by one or more lower-valent cations.

Several sublattice disordered oxides or sulphides have high ion transport ability at increasing temperature. These are superionic conductors, such as LiAISiCU, LiioGeP2Si2, Li3.6Sio_.6Po.4O4, NaSICON (sodium (Na) Super Ionic CONductor) with the general formula Nai_+xZr2P3-_xSi_xOi2 with 0 < x < 3, for example Na₃Zr₂PSi₂0i₂ (x = 2), or sodium beta alumina, such as NaAlnOi7, Nai ._dAIi 10i_7.3, and/or Nai.₇₆Lio.₃sAlio.₆₂0i_7.

High concentrations of ionic carriers can be induced in intrinsically insulating solids and creating high defective solids. Thus, the electrically conductive particles of the bed comprise one or more mixed oxides being an ionic or mixed conductor, namely being doped with one or more lower-valent cations, and/or one or more mixed sulphides being an ionic or mixed conductor, namely being doped with one or more lower-valent cations. With preference, the mixed oxides are selected from one or more oxides having a cubic fluorite structure being at least partially substituted with one or more lower-valent cations, preferentially selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and/or from one or more AB0₃-perovskites with A and B tri-valent cations, being at least partially substituted in A position with one or more lower- valent cations, preferentially selected from Ca, Sr, or Mg, and comprising at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe and/or a mixture thereof in B position; and/or from one or more ABO3- perovskites with A bivalent cation and B tetra-valent cation, being at least partially substituted with one or more lower-valent cations, preferentially selected from Mg, Sc, Y, Nd or Yb in the B position or with a mixture of different B elements in the B position; and/or from one or more A B C> -pyrochlores with A trivalent cation and B tetra-valent cation being at least partially substituted in A position with one or more lower-valent cations, preferentially selected from Ca or Mg, and comprising at least one of Sn, Zr and Ti in B position.

With preference, the mixed sulphides are selected from one or more sulphides having a cubic fluorite structure being at least partially substituted with one or more lower-valent cations, preferentially selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu; and/or the one or more mixed sulphides are selected from one or more ABS₃ structures with A and B tri-valent cations, being at least partially substituted in A position with one or more lower-valent cations, preferentially selected from Ca, Sr, or Mg and comprising at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe and/or a mixture thereof in B position; and/or from one or more ABS₃ structures with A bivalent cation and B tetra-valent cation, being at least partially substituted with one or more lower-valent cations, preferentially selected from Mg, Sc, Y, Nd or Yb in the B position or with a mixture of different B elements in the B position; and/or from one or more A2B2S7 structures with A trivalent cation and B tetra-valent cation being at least partially substituted in A position with one or more lower-valent cations, preferentially selected from Ca or Mg, and comprising at least one of Sn, Zr and Ti in B position.

Wth preference, 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 between 1 and 15 atom% based on the total number of atoms present in the one or more oxides having a cubic fluorite structure, preferably between 3 and 12 atom%, more preferably between 5 and 10 atom%.

Wth preference, the degree of substitution in the one or more mixed oxides doped with one or more lower-valent cations is between 1 and 50 atom % based on the total number of atoms present in the one or more AB0₃-perovskites with A and B tri-valent cations, in the one or more AB0₃-perovskites with A bivalent cation and B tetra-valent cation or in the one or more A₂B₂0₇-pyrochlores with A trivalent cation and B tetra-valent cation respectively, preferably between 3 and 20 atom %, more preferably between 5 and 15 atom%.

Said one or more oxides having a cubic fluorite structure, said one or more ABCh-perovskites with A and B tri-valent cations, said one or more ABCh-perovskites with A bivalent cation and B tetra-valent cation or said one or more A2B2C>7-pyrochlores with A trivalent cation and B tetra-valent cation being at least partially substituted with lower valent cations, said one or more ABS3 structures with A and B tri-valent cations, said one or more sulphides having a cubic fluorite structure, said one or more ABS3 structures with A bivalent cation and B tetra- valent cation, said one or more A2B2S7 structures with A trivalent cation and B tetra-valent cation being at least partially substituted with lower valent cations also means that the same element, being a high-valent cation, can be reduced in the lower-valent equivalent, for example, Ti(IV) can be reduced in Ti(lll) and/or Co(lll) can be reduced in Co(ll) and/or Fe(lll) can be reduced in Fe(ll) and/or Cu(ll) can be reduced in Cu(l).

Phosphate electrolytes such as UPO4 or LaPCU can also be used as electrically conductive particles.

Metallic carbides, transition metal nitrides and metallic phosphides can also be selected as electrically conductive particles. For example, metallic carbides are selected from iron carbide (Fe3C), molybdenum carbide (such as a mixture of MoC and M02C). For example, said one or more transition metal nitrides are selected from zirconium nitride (ZrN), tungsten nitride (mixture of W2N, WN, and WN2), vanadium nitride (VN), tantalum nitride (TaN), and/or niobium nitride (NbN). For example, said one or more metallic phosphides are selected from copper phosphide (CU₃P), indium phosphide (InP), gallium phosphide (GaP), sodium phosphide Na3P), aluminium phosphide (AIP), zinc phosphide (Zn3P2) and/or calcium phosphide (Ca3P2).

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

In the embodiment wherein the electrically conductive particles of the bed consist in silicon carbide, the person skilled in the art will have the advantage to conduct a step of pre-heating with a gaseous stream said fluidized bed reactor before conducting said endothermic reaction in the fluidized bed reactor. Advantageously, the gaseous stream is a stream of inert gas, i.e., nitrogen, argon, helium, methane or carbon dioxide. 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, for example between 600°C and 800°C or between 650°C and 750°C. Said gaseous stream of inert gas can also be used as the fluidification gas. The pre-heating of the said gaseous stream of inert gas is performed thanks to conventional means, including using electrical energy. The temperature of the gaseous stream used for the pre-heating of the bed doesn't need to reach the temperature reaction.

Indeed, the resistivity of silicon carbide at ambient temperature is high, to ease the starting of the reaction, it may be useful to heat the fluidized bed by external means, as with preference the fluidized bed reactor is devoid of heating means. Once the bed is heated at the desired temperature, the use of a hot gaseous stream may not be necessary. For example, at least one fluidized bed reactor is devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof. For example, all the fluidized bed reactors are devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof.

However, in an 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.

The pre-heating step may be also used in the case wherein electrically conductive particles different from silicon carbide particles are present in the bed. For example, it may be used when the content of silicon carbide in the electrically conductive particles of the bed is more than 80 wt.% based on the total weight of the electrically conductive particles of the bed, for example, more than 85 wt.%, for example, more than 90 wt.%, for example, more than 95 wt.%, for example, more than 98 wt.%, for example, more than 99 wt.%. However, a pre heating step may be used whatever is the content of silicon carbide particles in the bed.

In the embodiment wherein the electrically conductive particles of the bed comprise a mixture of silicon carbide particles and electrically conductive particles different from silicon carbide particles, the electrically conductive particles of the bed may comprise from 10 wt.% to 99 wt.% of silicon carbide particles based on the total weight of the electrically conductive particles of the bed; preferably, from 15 wt.% to 95 wt.%, more preferably from 20 wt.% to 90 wt.%, even more preferably from 25 wt.% to 80 wt.% and most preferably from 30 wt.% to 75 wt.%. For example, 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 comprises at least 40 wt.% of silicon carbide particles based on the total weight of the electrically conductive particles of the bed; preferably at least 50 wt.%, more preferably at least 60 wt.%, even more preferably at least 70 wt.% and most preferably at least 80 wt.%.

In an embodiment, the electrically conductive particles of the bed may comprise from 10 wt.% to 90 wt.% of electrically conductive particles different from silicon carbide particles based on the total weight of the electrically conductive particles of the bed; preferably, from 15 wt.% to 95 wt.%, more preferably from 20 wt.% to 90 wt.%, even more preferably from 25 wt.% to 80 wt.% and most preferably from 30 wt.% to 75 wt.%.

However, it may be interesting to keep the content of electrically conductive particles different from silicon carbide particles quite low in the mixture. Thus, in an embodiment, the electrically conductive particles of the bed comprise a mixture of silicon carbide particles and electrically conductive particles different from silicon carbide particles and electrically conductive particles of the bed comprises from 1 wt.% to 20 wt.% of electrically conductive particles different from silicon carbide based on the total weight of the electrically conductive particles of the bed; 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.%.

For example, 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.

Such electrically conductive particles, upon the electrification of the fluidized bed reactor, will heat up and because of their fluidification, will contribute to the raise and/or to the maintaining of the temperature within the reactor. The Joule heating of such electrically conductive material allows accelerating the heating of the reactant and/or of the catalyst that is present within the fluidized bed reactor.

The presence of electrically conductive particles different from silicon carbide particles in the bed allows applying the process according to the disclosure with or without the pre-heating step, preferably without the pre-heating step. Indeed, the electrically conductive particles, upon the electrification of the fluidized bed reactor, will heat up and because of their fluidification, will contribute to raising and/or maintaining the desired temperature within the reactor. In an embodiment, the electrically conductive particles are devoid of graphite and/or carbon black. In an embodiment, the electrically conductive particles are devoid of coke and/or petroleum coke.

The silicon carbide particles

For example, the silicon carbide is selected from sintered silicon carbide, nitride-bounded silicon carbide, recrystallised silicon carbide, reaction bonded silicon carbide and any mixture thereof.

Sintered SiC (SSiC) is a self-bonded material containing a sintering aid (typically boron) of less than 1% by weight.

Recrystallized silicon carbide (RSiC), a high purity SiC material sintered by the process of evaporation - condensation without any additives.

Nitride-bonded silicon carbide (NBSC) is made by adding fine silicon powder with silicon carbide particles or eventually in the presence of a mineral additive and sintering in a nitrogen furnace. The silicon carbide is bonded by the silicon nitride phase (S1₃N₄) formed during nitriding.

Reaction bonded silicon carbide (RBSC), also known as siliconized silicon carbide or SiSiC, is a type of silicon carbide that is manufactured by a chemical reaction between porous carbon or graphite with molten silicon. The silicon reacts with the carbon forming silicon carbide and bonds the silicon carbide particles. Any excess silicon fills the remaining pores in the body and produces a dense SiC-Si composite. Due to the left-over traces of silicon, reaction bonded silicon carbide is often referred to as siliconized silicon carbide. The process is known variously as reaction bonding, reaction sintering, self-bonding, or melt infiltration.

In general, high purity SiC particles have a resistivity above 1000 Ohm. cm, whereas sintered, reaction bonded and nitride-bonded can exhibit resistivities of about 100 to 1000 depending on the impurities in the SiC phase. Electrical resistivity of bulk polycrystalline SiC ceramics shows a wide range of resistivity depending on the sintering additive and heat-treatment conditions (Journal of the European Ceramic Society, Volume 35, Issue 15, December 2015, Pages 4137; Ceramics International, Volume 46, Issue 4, March 2020, Pages 5454). SiC polytypes with high purity possess high electrical resistivity (>10⁶ Q.cm) because of their large bandgap energies. However, the electrical resistivity of SiC is affected by doping impurities. N and P act as n-type dopants and decrease the resistivity of SiC, whereas Al, B, Ga, and Sc act as p-type dopants. SiC doped with Be, O, and V are highly insulating. N is considered the most efficient dopant for improving the electrical conductivity of SiC. For N doping of SiC (to decrease resistivity) Y₂O₃ and Y₂O₃- REM₂O₃ (REM, rare earth metal = Sm, Gd, Lu) have been used as sintering additives for the efficient growth of conductive SiC grains containing N donors. N-doping in SiC grains was promoted by the addition of nitrides (AIN, BN, S1₃N₄, TiN, and ZrN) or combinations of nitrides and REM₂O₃ (AIN- REM₂O₃ (REM = Sc, Nd, Eu, Gd, Ho, and Er) or TiN-Y₂0₃).

The catalytic composition

The thio-reforming catalyst comprises a catalytic composition that advantageously comprises one or more noble metals and/or one or more transition metals and/or the corresponding metal sulphides, phosphides, nitrides, carbides and/or silicides. For example, the thio-reforming catalyst is preferably a Cu, Mo, Ga, Co, Fe, Mo, Ni catalyst or a precious metal catalyst, or a combination thereof. Suitable catalysts comprise 10-60 wt.% Co, Mo, Ga, Fe, Ni or Cu combined with a support. Precious metal catalysts such as Pt, Pd, Rh, Au or Ru are dispersed on a suitable support and with metal loadings of typically 0.1-5.0 wt.%. Catalysts comprising one or more of Ni, Co, Pt and Rh are preferred. Suitable particulate catalyst supports are refractory oxides such as alumina (AI2O3), titania (T1O2), zirconia (Zr0₂), hafnia (Hf0₂), lanthania (I_a₂0₃), magnesia (MgO), ceria (Ce0₂), preferably zirconia stabilized with magnesia, lanthania, yttria (Y2O3) or ceria; metal-aluminates such as calcium aluminate and magnesium aluminate; and mixtures thereof. Particularly preferred particulate catalyst supports comprise alumina, alumina doped with silica and/or stabilized zirconia, e.g. lanthania-stabilized alumina, 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 resistive heating at the same time and which can be subdivided into two main groups: (1) Metallic alloys and (2) non-metallic resistors like silicon carbide (SiC) and molybdenum disilicide (M0S12), several mixed oxides with variable temperature optima and graphite. This latter option results in intimate contact between the catalytic active metal and the resistor particulate material.

The particulate catalyst support particles preferably have a particle size of from 5 to 300 pm as determined by sieving according to ASTM D4513-11, more preferably between 10 and 200 pm and most preferably between 30 and 150 pm. Metal contents on the support may be in the range of from 0.1 to 60.0 wt.%. Due to their different activities, preferably the precious metals such as Pt, Pd, Rh, Ru and Au are present in an amount in the range of from 0.1 to 5.0 wt.%, and the Co, Mo, Mo, Fe, Ga, Ni or Cu present in an amount in the range of from 10.0 to 60.0 wt.%. The catalytic metal or metal precursors may be dispersed over the surface of the particulate catalyst support by conventional impregnation of soluble metal compounds onto the particulate catalyst support followed by drying and calcination to convert the catalytic metal compound or compounds to their respective oxides. Alternatively, the catalytic metal or metal precursors may be dispersed over the surface of the particulate catalyst support material by precipitation, using metals sols or by deposition-precipitation methods employing metal salts that deposit insoluble metal compounds on the particulate catalyst support from solution upon heating. Further, metal salts can be ion-exchanged with counter cations on the support material. The metal precursors are reduced into the metallic state at elevated temperature by using hydrogen, carbon monoxide or hydrocarbons as reductants. This can be done before loading the catalyst in the fluidised bed reactor or in situ in the fluidised bed before feeding the feedstock or during feeding the feedstock.

The installation

The terms "bottom" and "top” are to be understood in relation to the general orientation of the installation or the fluidized bed reactor. Thus, "bottom" will mean greater ground proximity than "top" along the vertical axis. In the different figures, the same references designate identical or similar elements.

Figure 1 illustrates a prior art fluidized bed reactor 1 comprising a reactor vessel 3, a bottom fluid nozzle 5 for the introduction of a fluidizing gas and a reaction stream, an optional inlet 7 for the material loading, an optional outlet 9 for the material discharge and a gas outlet 11 and a bed 15. In the fluidized bed reactor 1 of figure 1 the heat is provided by preheating the feedstock by combustion of fossil fuels using heating means 17 arranged for example at the level of the line that provides the reactor with the fluidizing gas and the reaction stream.

The installation of the present disclosure is now described with reference to figures 2 to 5. For sake of simplicity, internal devices are known by the person in the art that are used in fluidized bed reactors, like bubble breakers, deflectors, particle termination devices, cyclones, ceramic wall coatings, thermocouples, etc... are not shown in the illustrations.

However, it is preferred that the at least one fluidized bed reactor comprising at least two electrodes and a bed comprising particles is devoid of packing.

Figure 2 illustrates a first installation with a fluidized bed reactor 19 where the heating and reaction zone are the same. The fluidized bed reactor 19 comprises a reactor vessel 3, a bottom fluid nozzle 21 for the introduction of a fluidizing gas and the reaction stream, an optional inlet 7 for the material loading, an optional outlet 9 for the material discharge and a gas outlet 11. The fluidized bed reactor 1 of figure 19 shows two electrodes 13 submerged in bed 25. Figure 3 illustrates an embodiment wherein at least one fluidized bed reactor 19 comprises a heating zone 27 and a reaction zone 29 with 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 to provide a reaction stream to the reaction zone from a distributor 33. As it can be seen in figure 3, the one or more fluid nozzles 23 can be connected to a distributor 33 to distribute the reaction stream inside bed 25.

Figure 4 illustrates an installation wherein at least one fluidized bed reactor 18 comprises at least two lateral zones with the outer zone being the heating zone 27 and the inner zone being the reaction zone 29. The heated particles of bed 25 from the outer zone are transferred to the inner zone by one or more openings 41 and mixed with the reaction stream. At the end of the reaction zone, the particles are separated from the reaction product and transferred to the heating zone.

Figure 5 illustrates the installation that comprises at least two fluidized bed reactors (37, 39) connected one to each other wherein at least one fluidized bed reactor is the heating zone 27 and one at least one fluidized bed reactor is the reaction zone 29.

The present disclosure also provides for an installation to be used in a process to perform an endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide to produce carbon disulphide and hydrogen, according to the first aspect, said installation comprising at least one fluidized bed reactor (18, 19, 37, 39) comprising: at least two electrodes 13; optionally a solid discharge system a reactor vessel 3; one or more fluid nozzles (21; 23) for the introduction of a fluidizing gas and/or of a reaction stream within at least one fluidized bed reactor (18, 19, 37, 39); and a bed 25 comprising particles; the installation is remarkable in that the particles of bed 25 comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of bed 25 are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C; and are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof. For example, one electrode is a submerged central electrode or two electrodes 13 are submerged within the reactor vessel 3 of at least one reactor (18, 19, 37).

The optional one or more solid discharge systems are systems that allow removing the solid which is generated during the reaction This can work by classification, namely based on particle size or particle density. Common classifier types are vibratory and rotary screeners, which classify materials by particle size, and cyclones, elutriation classifiers, and dynamic air classifiers, which classify materials by particle density.

The reaction stream comprises a mixture of hydrocarbon feedstock and hydrogen sulphide.

In a preferred embodiment, the at least one fluidized bed reactor (18, 19, 37, 39) is devoid of heating means. When stating that at least one of the fluidized bed reactors is devoid of “heating means”, it refers to “classical’ heating means, such as ovens, gas burners, hot plates and the like. There are no other heating means than the at least two electrodes of the fluidized bed reactor itself. For example, at least one fluidized bed reactor is devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof. For example, all the fluidized bed reactors are devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof.

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

For example, the reaction stream comprises a mixture of hydrocarbons feedstock and hydrogen sulphide.

For example, reactor 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 to carry out the chemical reaction at an industrial scale, for example at a weight hourly space velocity of said reaction stream comprised between 0.1 h ¹ and 100 h ¹, preferably comprised between 1.0 h ¹ and 50 h ¹, more preferably comprised between 1.5 h ¹ and 10 h ¹, even more preferably comprised between 2.0 h ¹ and 6.0 h ¹. The weight hourly space velocity is defined as the ratio of mass flow of the reaction stream to the mass of solid particulate material in the fluidized bed.

The at least one fluidized bed reactor (18, 19, 37) comprises at least two electrodes 13. For example, one electrode is in electrical connection with the outer wall of the fluidized bed reactor, while one additional electrode is submerged into the fluidized bed 25, or both electrodes 13 are submerged into the fluidized bed 25. Said at least two electrodes 13 are electrically connected and can be connected to a power supply (not shown). It is advantageous that said at least two electrodes 13 are made of carbon-containing material. The person skilled in the art will have an advantage that the electrodes 13 are more conductive than the particle bed 25.

For example, at least one electrode 13 is made of or comprises graphite; preferably, all or the two electrodes 13 are made of graphite. For example, one of the electrodes is the reactor vessel, so that the reactor comprises two electrodes, one being the submerged central electrode and one being the reactor vessel 3.

For example, at least one fluidized be reactor comprises at least one cooling device arranged to cool at least one electrode.

During use of the at least one fluidized bed reactor, an electric potential of at most 300 V is applied, 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.

Thanks to the fact that the power of the electric current can be tuned, it is easy to adjust the temperature within the reactor bed.

The reactor vessel 3 can be made of graphite. In an embodiment, it can be made of electro- resistive material that is silicon carbide or a mixture of silicon carbide and one or more carbon- containing materials.

With preference, the reactor vessel 3 comprises reactor wall made of materials that are corrosion-resistant materials and advantageously said reactor wall materials comprise nickel (Ni), SiAION ceramics, yttria-stabilized zirconia (YSZ), tetragonal polycrystalline zirconia (TZP) and/or tetragonal zirconia polycrystal (TPZ). SiAION ceramics are ceramics based on the elements silicon (Si), aluminium (Al), oxygen (O) and nitrogen (N). They are solid solutions of silicon nitride (S13N4), where Si-N bonds are partly replaced with Al-N and AI-0 bonds.

For example, the reactor vessel 3 is made of an electro-resistive material that is a mixture of silicon carbide and one or more carbon-containing material; and the electro-resistive material of the reactor vessel 3 comprises from 10 wt.% to 99 wt.% of silicon carbide based on the total weight of the electro-resistive material; preferably, from 15 wt.% to 95 wt.%, more preferably from 20 wt.% to 90 wt.%, even more preferably from 25 wt.% to 80 wt.% and most preferably from 30 wt.% to 75 wt.%. For example, the reactor vessel 3 is made of an electro-resistive material that is a mixture of silicon carbide and one or more carbon-containing materials; and the one or more carbon- containing materials are selected from graphite, carbon black, coke, petroleum coke and/or any mixture thereof; with preference, the carbon-containing material is or comprises graphite.

For example, the reactor vessel 3 is not conductive. For example, the reactor vessel 3 is made of ceramic.

For example, the 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 to provide a fluidizing gas to at least the heating zone from a distributor 31, one or more fluid nozzles 23 to provide a reaction stream to the reaction zone from a distributor 33, and means 41 to transport the particles from the heating zone 27 to the reaction zone 29 when necessary, and optional means 35 to transport the particles from the reaction zone 29 back to the heating zone 27.

For example, as illustrated in figure 3, the at least one fluidized bed reactor is a single one fluidized bed reactor 19 wherein the heating zone 27 is the bottom part of the fluidized bed reactor 19 while the reaction zone 29 is the top part of the fluidised bed reactor 19; with preference, the installation comprises one or more fluid nozzles 23 to inject a reaction stream between the two zones (27, 29) or in the reaction zone 29. The fluidized bed reactor 19 further comprises optionally an inlet 7 for the material loading, optionally an outlet 9 for the material discharge and a gas outlet 11. With preference, the fluidized bed reactor 19 is devoid of heating means. For example, electrodes 13 are arranged at the bottom part of the fluidized bed reactor 19, i.e. in the heating zone 27. For example, the top part of the fluidised bed reactor 19, i.e. the reaction zone 29, is devoid of electrodes. Optionally, the fluidized bed reactor 19 comprises means 35 to transport the particles from the reaction zone 29 back to the heating zone 27; such as by means of a line arranged between the top part and the bottom part of the fluidized bed reactor 19.

For example, as illustrated in figure 4, the installation comprises at least two lateral fluidized bed zones (27, 29) connected one to each other wherein at least one fluidized bed zone 27 is the heating zone and at least one fluidized bed zone 29 is the reaction zone. For example, the heating zone 27 is surrounding the reaction zone 29. Wth preference, the installation comprises one or more fluid nozzles 23 arranged to inject a reaction stream to the at least one reaction zone 29 by means of a distributor 33. The fluidized bed zones (27, 29) further comprise optionally an inlet 7 for the material loading and a gas outlet 11 . Wth preference, the at least one fluidized bed zone being the heating zone 27 and/or the at least one fluidized bed zone being the reaction zone 29 is devoid of heating means. For example, the at least one fluidized bed zone being the reaction zone 29 shows optionally an outlet 9 for the material discharge. One or more fluid nozzles 21 provide a fluidizing gas to at least the heating zone from a distributor 31. With one or more inlet devices 41 , heated particles are transported from the heating zone 27 to the reaction zone 29, and with one or more means 35 comprising downcomers, the separated particles are transported from the reaction zone 29 back to the heating zone 27. The fluidization gas for the heating zone 27 can be an inert diluent, like carbon dioxide, hydrogen, and/or nitrogen. In such configuration the fluidization gas for the heating zone can also comprise air or oxygen to burn deposited coke from the particles.

For example, as illustrated in figure 5, the installation comprises at least two fluidized bed reactors (37, 39) connected one to each other wherein 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. Wth preference, the installation comprises one or more fluid nozzles 23 arranged to inject a reaction stream to the at least one fluidized bed reactor 39 being the reaction zone 29. The fluidized bed reactors (37, 39) further comprise optionally an inlet 7 for the material loading and a gas outlet 11. Wth preference, the at least one fluidized bed reactor 37 being the heating zone 27 and/or the at least one fluidized bed reactor 39 being the reaction zone 29 is devoid of heating means. For example, the at least one fluidized bed reactor 39 being the reaction zone 29 shows optionally an outlet 9 for the material discharge. Using the inlet device 41 heated particles are transported from the heating zone 27 to the reaction zone 29 when necessary and using device 35 the separated particles after the reaction zone are transported from the reaction zone back to the heating zone. The fluidization gas for the heating zone can be an inert diluent, like carbon dioxide, hydrogen and/or nitrogen. In such a configuration the fluidization gas for the heating zone can also comprise air or oxygen to burn deposited coke from the particles.

For example, the at least one fluidized bed reactor 37 being the heating zone 27 comprises at least two electrodes 13 whereas the at least one fluidized bed reactor 39 being the reaction zone 29 is devoid of electrodes.

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

For example, the at least two fluidized bed reactors (37, 39) are connected one to each other by means 35 suitable to transport the particles from the reaction zone 29 back to the heating zone 27, such as one or more lines. The thio-reforminq reaction

The hydrocarbons feedstock, to be fed to the reformer, is advantageously pre-heated using heat contained in the reactor effluent. The hydrogen sulphide or its precursors (mercaptans, disulphides) could be added directly into the reactor or pre-mixed with said hydrocarbons feedstock before entering the reactor. The hhS/carbon (carbon atoms in the hydrocarbons) molar ratio in the combined reformer feedstock can be controlled to avoid carbon deposition on the catalyst and slip of methane (incomplete conversion of methane) and is typically in the range of from 0.15 to 5.0, more preferable between 0.3 to 4.0, even more preferable between 1.0 to 3.0. Subsequently, the gas-hhS mixture is heated to a temperature of 700 to 1200°C at pressures above 1.0 MPa by passing through the electrothermal fluidised bed reformer vessel containing the thio-reforming catalyst. The gas stream leaving the fluidised bed reactor contains H₂, CO, C0₂, unconverted H2S and hydrocarbons as well as possibly inert gas constituents of the feed gas stream.

It is a preferred embodiment of the present disclosure to add carbon dioxide either to the hydrocarbon feedstock or to the H2S stream to have a CO2 to carbon (carbon atoms in the hydrocarbons) molar ratio in the combined reformer feedstock from 0.05 to 1 , more preferably from 0.1 to 0.75, even more preferably from 0.2 to 0.3.

It is a preferred embodiment of the present disclosure that solid materials that exhibit only sufficiently low resistivity at high temperatures can be heating by external means before reaching the high enough temperature where resistive heating with electricity overtakes or by mixing with a sufficiently low resistivity solid at a low temperature so that the combined resulting resistivity allows to heat the fluidized bed to the desired reaction temperature.

It is a preferred embodiment of the present disclosure to combine the electrothermal fluidised bed reformer with a pre-reformer before in case the hydrocarbon feedstock contains more than 5 wt.% of hydrocarbons having two or more carbons or with an autothermal reformer behind or a combination of heat-exchanger reformer and/or an autothermal reformer behind. In such cases, the required reaction heat is supplied either by electrical heating or internal combustion (partial oxidation).

It is a preferred embodiment of the present disclosure to withdraw continuously or intermittently solid particulate material and particulate catalyst, containing carboneous depositions, from the electrothermal fluidised bed vessel, transporting it to a fluidised bed regeneration vessel, burning the carboneous depositions with a stream containing oxygen and optionally carbon dioxide, transporting the at least partially regenerated solid particulate material and particulate catalyst back into the electrothermal fluidised bed reformer vessel. Optionally the combustion products, carbon monoxide, carbon dioxide and sulphur oxides are injected in the main electrothermal fluidized bed reformer.

It is a preferred embodiment of the present disclosure to recover the sensible and latent heat in the produced synthesis gas to preheat the reformer feedstock (both the hydrocarbons and hydrogen sulphide).

Test and determination methods

The conversion of the methane {X_CH is determined according to formula (1):

wherein [CH₄]¹ and [CH₄\^r are the molar amount of methane in the (initial) fluid stream and in the (final) reactor effluent (or product stream) respectively.

A similar formula is to be used for determining the conversion of hydrogen sulphide (¾₂s).

The selectivity in hydrogen ( S_Hz ) corresponds to the amount of hydrogen formed from all the reacted source of hydrogen in the feed which were converted into hydrogen according to the chemical equation ChU + H2S CS2 + 4H₂. Therefore, the selectivity in hydrogen is determined according to formula (2):

wherein (i) is the initial amount in the feed and (f) is the final amount in the effluent.

The selectivity in carbon disulphide ( S_CSz ) is calculated on carbon basis and determined according to formula (3):

S_Cs₂ = 100

Gas chromatography experiments were carried out to determine quantitatively the conversion and the selectivity of the reaction. It was performed on a silica BOND column (60 m x 0.32 mm) using Agilent operated by ChemStation software.

Claims

1. A process to perform an endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide to produce carbon disulphide and hydrogen said process is characterized in that it comprises the steps of: a) providing at least one fluidized bed reactor comprising at least two electrodes, a bed comprising particles, and optionally a solid discharge system; b) putting the particles of the bed in a fluidized state by passing upwardly through the said bed a fluid stream, to obtain a fluidized bed; c) heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the endothermic thio-reforming reaction; d) obtaining a reactor effluent containing hydrogen, carbon disulphide, unconverted hydrogen sulphide and hydrocarbons, and optionally sulphur and/or methanethiol; wherein the particles of the bed comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed are electrically conductive particles, have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C, and are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower- valent cations and/or any mixture thereof; and wherein the step (c) of heating the fluidized bed is performed by passing an electric current through the fluidized bed.

2. The process according to claim 1, characterized in that from 50 wt.% to 100 wt.% of the electrically conductive particles of the bed based on the total weight of the electrically conductive particles of the bed are one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof.

3. The process according to claim 1 or 2, characterized in that the electrically conductive particles of the bed comprise one or more non-metallic resistors selected from silicon carbide, molybdenum disilicide or a mixture thereof.

4. The process according to claim 1 to 3, characterized in that the electrically conductive particles of the bed comprise one or more mixed oxides being doped with one or more lower-valent cations.

5. The process according to claim 4, characterized in that the mixed oxides are one or more oxides having a cubic fluorite structure partially being at least partially substituted with one or more lower-valent cations.

6. The process according to claim 5, characterized in that that the one or more lower- valent cations are selected from Sm, Gd, Y, Sc, Yb, Mg, Ca, La, Dy, Er, Eu.

7. The process according to any one of claims 4 to 6, characterized in that the mixed oxides are one or more ABCh-perovskites with A and B tri-valent cations, being at least partially substituted in A position with one or more lower-valent cations and comprising at least one of Ni, Ga, Co, Cr, Mn, Sc, Fe and/or a mixture thereof in B position.

8. The process according to claim 7, characterized in that said one or more lower-valent cations are selected from Ca, Sr, or Mg.

9. The process according to any one of claims 4 to 8, characterized in that the mixed oxides are one or more one or more AB0₃-perovskites with A bivalent cation and B tetra-valent cation, being at least partially substituted with one or more lower-valent cations, in the B position or with a mixture of different B elements in the B position.

10. The process according to claim 9, characterized in that the one or more lower-valent cations are selected from Mg, Sc, Y, Nd or Yb.

11. The process according to any one of claims 4 to 10, characterized in that the mixed oxides are one or more AaBaOypyrochlores with A trivalent cation and B tetra-valent cation being at least partially substituted in A position with one or more lower-valent cations and comprising at least one of Sn, Zr and Ti in B position.

12. The process according to claim 11 , characterized in that said one or more lower-valent cations are selected from Ca or Mg.

13. The process according to any one of claims 1 to 12, characterized in that the electrically conductive particles of the bed comprise one or more metallic alloys.

14. The process according to any one of claims 1 to 13, characterized in that the electrically conductive particles of the bed comprise one or more superionic conductors.

15. The process according to claim 14, characterized in that the one or more superionic conductors are selected from LiAISiCU, LiioGeP2Si2, Li3.6Sio.6Po.4O4, sodium superionic conductors, or sodium beta alumina.

16. The process according to any one of claims 1 to 15, characterized in that the catalytic composition comprises one or more metals.

17. The process according to claim 16, characterized in that said one or more metals are selected from Ni, Ga, Cu, Fe, Co, Mo, Pt, Pd, Rh, Ru and/or Au.

18. The process according to claim 16 or 17, characterized in that the catalytic composition comprises one or more metals in a content ranging between 0.1 and 60.0 wt.% of the total weight of said catalytic composition.

19. The process according to any one of claims 1 to 18, characterized in that the catalytic composition comprises a catalytic support.

20. The process according to claim 19, characterized in that the catalytic support is electrically conductive particles.

21. The process according to claim 19 or 20, characterized in that said catalytic support is selected from AI2O3, T1O2, Zr02, Hf02, La203, and/or Ce02.

22. The process according to any one of claims 1 to 21 , characterized in that the fluid stream provided in step (b) comprises a mixture of hydrocarbons feedstock and hydrogen sulphide.

23. The process according to claim 22, characterized in that the fluid stream provided in step (b) further comprises carbon oxides; and wherein the reactor effluent obtained at step (d) and comprising hydrogen, carbon disulphide, unconverted hydrogen sulphide and hydrocarbons further comprises carbon oxides.

24. The process according to claim 23, characterized in that the process further comprises the step (e) of transforming said reactor effluent into thiol-derivative of said hydrocarbons.

25. The process according to claim 23 or 24, characterized in that the step (f) of transforming said reactor effluent into higher hydrocarbons.

26. The process according to any one of claims 1 to 25, characterized in that, wherein the at least one fluidized bed reactor provided in step a) comprises a heating zone and a reaction zone and wherein the fluid stream provided in step b) is provided to the heating zone and comprises diluent gases and/or hydrogen sulphide, the step c) of heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the thio-reforming reaction of a hydrocarbon feedstock comprises the following sub steps: heating the fluidized bed to a temperature ranging from 500°C to 1200°C by passing an electric current through the heating zone of the at least one fluidized bed, transporting the heated particles from the heating zone to the reaction zone, in the reaction zone, putting the heated particles in a fluidized state by passing upwardly through the said bed of the reaction zone a fluid stream comprising a mixture of hydrocarbon feedstock, hydrogen sulphide and optional diluent gases to obtain a fluidized bed and to conduct the thio-reforming reaction on the hydrocarbon feedstock.

27. The process according to claim 26, characterized in that the step c) of heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the thio- reforming reaction of a hydrocarbon feedstock further comprises the sub-steps of recovering the particles from the reaction zone and recycling them to the heating zone.

28. An installation to perform a process for an endothermic thio-reforming reaction of hydrocarbons with hydrogen sulphide to produce carbon disulphide and hydrogen according to any one of claims 1 to 27, said installation comprising at least one fluidized bed reactor (18, 19, 37, 39) comprising:

- at least two electrodes (13);

- a reactor vessel (3);

- one or more fluid nozzles (21 , 23) for the introduction of a fluidizing gas and/or of a reaction stream within at least one fluidized bed reactor (18, 19, 37, 39); and

- a bed (25) comprising particles; the installation is characterized in that the particles of the bed (25) comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed (25) are electrically conductive particles, have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and are or comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower-valent cations and/or any mixture thereof.

29. The installation according to claim 28, characterized in that said installation further comprises a solid discharge system.

30. The installation according to claim 28 or 29, characterized in that at least one fluidized bed reactor (18, 19, 37, 39) is devoid of heating means selected from ovens, gas burners, hot plates, or any combination thereof.

31. The installation according to any one of claims 28 to 30 to perform a thio-reforming reaction in a process according to claim 26 or 27, characterized in that the 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 (23) to provide a mixture of a hydrocarbons feedstock and hydrogen sulphide to the reaction zone (29).

32. The installation according to claim 31, characterized in that the at least one fluidized bed reactor (18, 19, 37, 39) further comprises means (35) to transport the particles of the bed (25) from the reaction zone (29) back to the heating zone (27).

33. The installation according to claim 31 or 32, characterized in that it comprises at least two fluidized bed reactors (37, 39) connected one to each other wherein at least one reactor (37) is the heating zone (27) and at least another reactor (39) is the reaction zone (29).

34. The installation according to claim 31 or 32, characterized in that the at least one fluidized bed reactor (19) is a single one fluidized bed reactor wherein the heating zone (27) is the bottom part of the fluidized bed reactor (19) while the reaction zone (29) is the top part of the fluidised bed reactor (19).

35. The installation according to claim 31 or 32, characterized in that the at least one fluidized bed (18) comprises at least two lateral zones being an outer zone and an inner zone wherein the outer zone is surrounding the inner zone, with the outer zone being the heating zone (27) and the inner zone being the reaction zone (29).

36. The installation according to any one of claims 28 to 35, characterized in that the at least one fluidized bed reactor is devoid of packing.

37. Use of a bed (25) comprising particles in at least one fluidized bed reactor (18, 19, 37, 39) to perform a process of thio-reforming reaction of hydrocarbons with hydrogen sulphide according to any one of claims 1 to 27, the use is characterized in that the particles of the bed (25) comprise electrically conductive particles and particles of a catalytic composition, wherein at least 10 wt.% of the particles based on the total weight of the particles of the bed (25) are electrically conductive particles, have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and comprise one or more selected from one or more metallic alloys, one or more non-metallic resistors, one or more metallic carbides, one or more transition metal nitrides, one or more metallic phosphides, one or more superionic conductors, one or more phosphate electrolytes, one or more mixed oxides being doped with one or more lower-valent cations, and/or one or more mixed sulphides being doped with one or more lower- valent cations and/or any mixture thereof.

38. The use according to claim 37, characterized in that the use comprises heating the bed (25) comprising particles to a temperature ranging from 500°C to 1200°C in a first reactor (37), transporting the heated particle bed from the first reactor (37) to a second reactor (39) and providing a mixture of a hydrocarbons feedstock and hydrogen sulphide to the second reactor (39).

39. The use according to any one of claims 37 or 38, characterized in that the at least one fluidized bed reactor comprising at least two electrodes and a bed comprising particles is devoid of packing.

40. The use of an installation with at least one fluidized bed reactor (18, 19, 37, 39) to perform a thio-reforming reaction, characterized in that the installation is according to any one of claims 28 to 36.