Steam cracking plant and process with a heat exchanger reactor using a thermal storage system

Abstract

The invention relates to a steam cracking installation and process employing at least one heat exchanger reactor. The heat required for the steam cracking reaction is supplied by a working fluid circulating in at least one closed-loop circuit (130), connected to an inlet of the heat exchanger reactor (112) and to the corresponding outlet, and comprising: at least one heating device (131, 132) upstream of the heat exchanger reactor (112) with respect to the working fluid circulation, at least one thermal storage system (170) mounted in parallel or downstream of at least one heating device, and upstream of the heat exchanger reactor, at least one heat exchanger (134, 135) located downstream of the heat exchanger reactor (112) and upstream of at least one heating device (131, 132), at least one circulation device (138). Figure for the abbreviation: Figure 1

Description

Title of the invention: INSTALLATION AND METHOD FOR STEAM CRACKLING WITH A HEAT EXCHANGER REACTOR USING A THERMAL STORAGE SYSTEM Technical field of the invention

[0001] The present invention relates to a steam cracking installation and process employing at least one heat exchanger reactor and using a thermal storage system. Technological background

[0002] The hydrocarbon steam cracking process makes it possible to produce light olefins, and more particularly ethylene and propylene. It consists of thermally cracking a mixture of hydrocarbons and steam in one or more reactors at high temperatures of around 800 to 850 °C and under low pressures (1 to 3 bar) to break the carbon-hydrogen and / or carbon-carbon bonds and produce unsaturated hydrocarbons in the reactor(s). The effluents exiting the reactor(s) are then quenched in one or more heat exchangers, generally designated by the acronyms TLX or TLE ("Transfer Line Exchanger"), in order to limit secondary reactions such as the polymerization of olefins, dienes, and acetylenes. The cooled effluents are then fractionated.

[0003] Most steam cracking plants today use the combustion of a fossil fuel, generally a methane-rich gas, to provide the thermal energy required for steam cracking, which generates significant CO2 emissions. Furthermore, in conventional steam cracking furnaces, the heat resulting from gas combustion is transferred to the tubes carrying the feedstock to be cracked primarily by radiation, with minimal convection heat transfer. Because the combustion gas temperature is significantly higher than the surface temperature of these tubes and because radiation heat transfer is not completely homogeneous, localized temperature spikes can occur, promoting coking of the reaction tubes and necessitating more frequent plant shutdowns.

[0004] Increasingly important environmental concerns, however, require replacing the fossil fuel traditionally used to provide the heat needed for steam cracking with decarbonized energy (without CO2 emissions) and in particular renewable energy, and especially renewable electricity produced by wind turbines and / or solar panels.

[0005] There is therefore a need for a steam cracking installation and process that enables the steam cracking reaction to be carried out at a lower environmental cost. There is also a need for a steam cracking installation and process that limits localized temperature increases.

[0006] Document FR 2 675 498 A1 describes a steam cracking process that partially overcomes these drawbacks. To this end, the steam cracking reaction is carried out inside a shell-and-tube heat exchanger reactor. The thermal energy required for the reaction is supplied by the combustion of a gas mixture, which is partially performed inside the heat exchanger reactor. The gas mixture to be burned is produced by a gas generator and then enters the heat exchanger reactor, optionally after passing through an afterburner chamber. The resulting production gases are sent to another gas-gas heat exchanger where the steam cracking feedstock is preheated before entering the heat exchanger reactor. To maintain a substantially constant temperature in the reaction tubes, injection tubes are arranged inside the heat exchanger reactor.

[0007] The process described in this document has the disadvantage of requiring the combustion of gases emitting CO2. Furthermore, since part of the gas combustion occurs inside the heat exchanger reactor, additional devices must be provided in the latter to obtain a homogeneous temperature, which complicates the manufacture of this reactor.

[0008] The invention aims to overcome all or part of the disadvantages of the prior art. Summary of the invention

[0009] To this end, the invention proposes a steam cracking plant comprising:

[0010] - at least one shell-and-tube heat exchanger reactor, each reactor- heat exchanger comprising means for supplying a suitable gaseous mixture comprising at least one hydrocarbon, connected to an inlet selected from a tube inlet and a shell inlet, and means for discharging a hot gaseous effluent connected to a corresponding outlet of the tubes or the shell,

[0011] - a cooling section adapted for performing quenching, connected to the means evacuation of each heat exchanger reactor,

[0012] characterized in that it further comprises:

[0013] - at least one closed-loop circuit in which a working fluid circulates, this circuit being connected on one side to the other inlet of at least one heat exchanger reactor chosen from a tube inlet and a shell inlet, and on the other side to the corresponding tube or shell outlet, each circuit comprising:

[0014] at least one working fluid heating device located upstream, in particular immediately upstream, of at least one heat exchanger reactor with respect to the working fluid circulation,

[0015] at least one thermal storage system coupled to the circuit via a bypass pipe, and mounted in parallel with or downstream of at least one heating device, and upstream of at least one heat exchanger reactor,

[0016] at least one heat exchanger located downstream of at least one heat exchanger reactor and upstream of at least one heating device,

[0017] at least one device for circulating the working fluid,

[0018] a management system for at least one closed-loop circuit heating device and at least one thermal storage device, configured to: (i) during a charging phase of at least one thermal storage system, operate at least one heating device of said circuit to heat the working fluid to a target temperature, and accumulate heat within at least one thermal storage system, (ii) in a discharge phase of at least one thermal storage system: - circulate through the at least thermal storage system all, or a fraction, of the working fluid flow circulating in said circuit to heat it to the target temperature, or a first temperature, respectively - and stop at least one heating device of said circuit, or command it to heat to a second temperature the remaining fraction of the working fluid flow which, in mixing with the fraction of working fluid at the first temperature, reaches the target temperature.

[0019] There is therefore no combustion inside the heat exchanger reactor so that the structure of the latter can be simplified and the risk of hot spots is limited.

[0020] In addition, the use of one or more thermal storage systems makes it possible to use electricity when it is cheaper and / or produced from renewable sources to accumulate calories within at least one thermal storage system, and thus limit the overall cost and / or the ecological footprint of the heating required for the steam cracking reaction.

[0021] At least one thermal storage system may include, or be composed of, one or more thermal storage devices, each containing a solid or liquid thermal storage medium. This system may optionally include one or more electric heating devices, integrated or not with the thermal storage device(s). The management system is then configured to operate this electric heating device during the charging phase for heat accumulation. The electric heating device of the thermal storage system may to be chosen from a Joule effect heating device, a microwave heating device, a shock wave heating device, a plasma heating device, an induction heating device, a heat pump.

[0022] Advantageously, at least one closed-loop circuit can be connected to the shell of at least one heat exchanger reactor. The gas mixture to be steam cracked then circulates through the tubes of at least one heat exchanger reactor. This can, in particular, facilitate control of the residence time and pressure of the gas mixture inside the reactor.

[0023] Advantageously, at least one closed-loop circuit may include at least two heating devices connected in series and / or parallel. This can facilitate heating the working fluid to the desired temperature. Optionally, one or more thermal storage systems may be coupled to said circuit and connected in parallel or downstream of one or more of these heating devices, of which there must be at least two, and upstream of at least one heat exchanger reactor.

[0024] Preferably, at least one heating device in said circuit is a heating device that does not emit CO2, either because there is no combustion, the heating device requiring only an electrical supply, or because combustion does not emit CO2.

[0025] The heating device for said circuit may be in the form of a boiler, a furnace or a superheater, preferably not emitting CO2.

[0026] Advantageously, at least one heating device of said circuit can be chosen from a Joule effect heating device, a microwave heating device, a shock wave heating device, a plasma heating device, an induction heating device, a heat pump, a hydrogen furnace.

[0027] Advantageously, the cooling section may include at least one heat exchanger connected on the one hand to the exhaust means of at least one heat exchanger reactor and on the other hand to the supply means of at least one heat exchanger reactor so as to preheat the gas mixture entering the latter by means of the gaseous effluent exiting the latter.

[0028] Advantageously, at least one heat exchanger in the cooling section can be connected to at least one heat exchanger in said circuit to receive at least one component of the preheated gas mixture. This notably improves the overall energy performance of the installation.

[0029] Advantageously, the at least one closed-loop circuit may include a first and a second heat exchanger mounted in series downstream of the at least one heat exchanger reactor, the first heat exchanger being connected to a water supply line, in particular in the form of steam, and adapted for the The second heat exchanger is connected to a supply line for a component of the gas mixture, particularly hydrocarbons, and is designed to preheat it before it enters at least one heat exchanger reactor or before it enters a heat exchanger in the cooling section. This also improves the overall energy performance of the installation.

[0030] Advantageously, in another embodiment allowing for improved overall energy performance of the installation, the at least one closed-loop circuit comprises a first and a second heat exchanger mounted in series downstream of at least one heat exchanger reactor, the first heat exchanger being connected to the circuit, on the one hand, upstream, in particular immediately upstream, of at least one heating device and downstream of the second heat exchanger, and on the other hand, downstream, in particular immediately downstream, of at least one heat exchanger reactor and upstream of the second heat exchanger, the second heat exchanger being connected to a water supply line, in particular in liquid form, and adapted to preheat water using the working fluid. The closed-loop circuit 130 thus passes twice through the first heat exchanger.

[0031] In a variant of this embodiment, the installation may further comprise at least two preheating heat exchangers: the first preheating heat exchanger being connected on one side to a heat exchanger of the cooling section to receive a cooled gaseous effluent, and on the other side to the second heat exchanger of the closed loop circuit to further heat and vaporize the water exiting the latter, the second preheating heat exchanger being connected on one side to the heat exchanger of the cooling section to supply it with at least one constituent of the gaseous mixture, in particular hydrocarbons, preheated, and on the other side to the first preheating heat exchanger to receive the further cooled gaseous effluent.

[0032] These preheating heat exchangers thus serve to preheat the constituents of the gas mixture before their introduction into the heat exchanger reactor, and in particular before their entry into the heat exchanger of the cooling section used to rapidly cool the gaseous effluent and preheat the gas mixture.

[0033] In particular, the cooling section then includes a heat exchanger typically connected on the one hand to the exhaust means of at least one heat exchanger reactor and on the other hand to the supply means of at least one heat exchanger reactor so as to preheat the gas mixture entering the latter by means of the gaseous effluent exiting the latter.

[0034] Advantageously, the cooling section may include a first and a second heat exchanger mounted in series: the first heat exchanger being then connected on the one hand to the evacuation means of at least one heat exchanger reactor, and on the other hand to a preheating heat exchanger located upstream of at least one heat exchanger reactor with respect to the fluid circulation, so as to preheat a constituent of the gas mixture, the second heat exchanger being connected on one side to the first heat exchanger and on the other side to the preheating heat exchanger and to at least one heat exchanger of the closed loop circuit, to receive at least one constituent of the preheated gas mixture.

[0035] In particular, the preheating heat exchanger can be connected to the first heat exchanger of the cooling section by another closed loop circuit in which another working fluid circulates, typically water in the form of vapor and / or liquid.

[0036] In one variant, the second heat exchanger of the closed loop circuit 130 can be connected to the preheating heat exchanger in order to supply it with the constituent of the gas mixture preheated by the working fluid.

[0037] The invention also relates to a steam cracking process of a gaseous mixture of a hydrocarbon feedstock and water vapor, in particular suitable for implementation by a steam cracking plant according to the invention, said process comprising a heating phase in a heating section under suitable conditions, which delivers a hot steam cracking effluent, in particular rich in ethylene, and a rapid cooling phase of said effluent in a cooling section under suitable conditions, and said cooled steam cracking effluent is recovered.

[0038] According to the invention: - the gaseous mixture, preferably pre-heated, is introduced into at least one pressure shell and tube heat exchanger reactor via an inlet of the latter chosen from a tube inlet and a shell inlet, and the gaseous mixture is circulated inside the tubes or the shell of said heat exchanger reactor, - The heating phase of the gas mixture is carried out in at least one heat exchanger reactor according to the following steps: (a) A working fluid is circulated within a closed-loop circuit, this circuit being connected on one side to the other inlet of at least one heat exchanger reactor selected from a tube inlet and a shell inlet, and on the other side to the corresponding tube or shell outlet, and said working fluid is heated to a target temperature above the temperature at which the mixture gaseous must be heated by means of at least one closed-loop circuit heating device and / or by means of at least one thermal storage system for said circuit in the following manner: (i) in a charging phase of at least one thermal storage system, at least one heating device of said circuit is operated to heat the working fluid to the target temperature, and heat is accumulated within at least one thermal storage system, (ii) in a discharge phase of at least one thermal storage system: - the entire, or a fraction, of the working fluid flow circulating in said circuit is circulated through the at least thermal storage system to heat it to the target temperature, or to a first temperature, respectively, - and at least one heating device of said circuit is stopped, or is controlled to heat to a second temperature the remaining fraction of the working fluid which, by mixing with the fraction of working fluid at the first temperature, reaches the target temperature, (b) the working fluid is introduced at the target temperature into the heat exchanger reactor, the cooled working fluid is recovered and reinjected into the closed-loop circuit upstream of at least one heating device of said circuit, and a hot steam cracking effluent is recovered and sent immediately to the cooling section.

[0039] In particular, it is possible to operate the thermal storage system in load mode when electricity is cheaper and / or comes from decarbonized sources (wind, solar, nuclear power plant, hydroelectric, ...), which makes it possible to decarbonize the electrical consumption of the installation and / or reduce operating costs.

[0040] When at least one storage system includes at least one electric heating device, during the charging phase, it may be operated to accumulate calories, and optionally stopped during the discharging phase.

[0041] Advantageously, the gas mixture can be circulated inside the tubes of at least one heat exchanger reactor.

[0042] Advantageously, the method according to the invention may further comprise at least one of the following features:

[0043] - the working fluid is chosen from water, CO2, helium, nitrogen or argon, - The target temperature of the working fluid is 900 to 1600 °C, preferably 1000 to 1400 °C. - the working fluid pressure is from 30 barg to 80 barg.

[0044] Advantageously, the gaseous effluent that has circulated in at least one heat exchanger reactor can be recovered and sent to at least one heat exchanger in the cooling section to cool it rapidly and preheat the gaseous mixture before it enters at least one heat exchanger reactor.

[0045] Advantageously, the working fluid that has circulated in at least one heat exchanger reactor can be recovered and sent to at least one heat exchanger of the closed-loop circuit in which at least one fluid selected from (i) at least one constituent of the gas mixture is preheated before entering at least one heat exchanger reactor or before entering at least one heat exchanger of the cooling section, (ii) water, (iii) steam, and (iv) the working fluid is preheated before entering at least one heat exchanger reactor.

[0046] In particular, the following embodiments may be envisaged:

[0047] - the working fluid having circulated in at least one heat exchanger reactor is sent to a first heat exchanger of the closed loop circuit to heat water vapor, in particular before preheating it in a heat exchanger of the cooling section, then the working fluid is sent to a second heat exchanger of said circuit to heat another constituent of the gas mixture (e.g. hydrocarbons), in particular before preheating it in a heat exchanger of the cooling section.

[0048] - the working fluid having circulated in at least one heat exchanger reactor The working fluid is sent to a first heat exchanger in the closed-loop circuit to heat the working fluid before it is heated by at least one heating device. It then goes to a second heat exchanger in the same circuit to heat water, specifically before its vaporization in a first preheating heat exchanger that receives heat from the effluent exiting a heat exchanger in the cooling section. The recovered effluent can then be sent to yet another preheating heat exchanger to preheat another component of the gas mixture (particularly hydrocarbons) before it mixes with the dilution steam exiting the first preheating heat exchanger. The mixture is then preheated in a heat exchanger in the cooling section.

[0049] - the working fluid having circulated in at least one heat exchanger reactor is sent to a first heat exchanger in the closed-loop circuit to heat steam, notably before its preheating in a heat exchanger in the cooling section, then the working fluid is sent to a second heat exchanger in the same circuit to heat another component of the gas mixture (notably hydrocarbons), the hot effluent having circulated in at least one reactor-heat exchanger being sent to a first and a second heat exchanger connected in series to the cooling section, the second heat exchanger of the cooling section receiving, on the one hand, the component of the gas mixture preheated first by the second heat exchanger of said circuit and then by a preheating heat exchanger, and on the other hand, the dilution steam heated by the first heat exchanger of said circuit. The preheating heat exchanger is advantageously connected to the first heat exchanger of the cooling section by another closed-loop circuit in which another working fluid circulates, typically water in liquid and / or vapor form.

[0050] The heating section of the installation and process according to the invention may comprise several heat exchanger reactors mounted in parallel, for example 2 to 10, preferably 2 to 8. In this case, maintenance can be carried out on one of the heat exchanger reactors while the others are in operation. Although the invention makes it possible to limit coking, it can nevertheless accumulate over the long term. The maintenance operation can then be a decoking. Detailed description of the invention Description of the figures

[0051] The invention is now described with reference to the accompanying, non-limiting drawings, in which:

[0052] Figure [1] schematically represents a steam cracking installation according to a first embodiment,

[0053] Figure [Fig. 2] schematically represents a steam cracking installation according to a second embodiment,

[0054] Fig. 3 schematically represents a steam cracking installation according to a third embodiment.

[0055] In the figures, the same elements are designated by the same references.

[0056] Fig. 1 represents a steam cracking plant 100 comprising a heating section 110 including at least one shell and tube heat exchanger reactor 112, here only one and a cooling section 120.

[0057] The heat exchanger reactor 112 (also referred to as the "heat exchanger reactor" in the following) includes a tube inlet 113, a tube outlet 114, a shell inlet 115 and a shell outlet 116.

[0058] The reactor-exchanger 112 further includes means for supplying a suitable gaseous mixture comprising at least one hydrocarbon. These supply means here include a conduit 117 connected in this example to the inlet 113 of the tubes.

[0059] The reactor-exchanger 112 also includes means for venting a hot gaseous effluent. These venting means include a pipe 118 connected in this example to the outlet 114 of the tubes.

[0060] The invention is not, however, limited to this embodiment, and it could be envisaged that the pipes 117 and 118 be connected respectively to the inlet 115 and outlet 116 of the calender, although this is not preferred. Implementing the steam cracking reaction inside the tubes of the reactor-exchanger 112 has the advantage of facilitating control of the residence time and pressure of the gas mixture in the reactor-exchanger 112, and of simplifying the construction of the reactor. Indeed, given the relatively high steam cracking pressures, implementing the reaction in the calender would require significantly thickening its walls.

[0061] A reactor-exchanger 112 typically has an elongated shape, generally arranged vertically.

[0062] In general, the reactor-exchanger 112 contains a plurality of reaction tubes, usually of small diameter, for example 10 to 40 mm. A reactor-exchanger can contain a thousand tubes of approximately 20 mm in diameter, for example made of Incoloy-type steel, with a high nickel content. These tubes are typically substantially parallel to each other and substantially parallel to the axis of the reactor-exchanger.

[0063] These tubes for example are adapted to receive, by means of a parallel supply, a mixture preheated to 580-680 °C under 1.5 to 3 bar, of steam and hydrocarbons by the line 117 opening at the lower end of the reactor 112, so that the hydrocarbon gas mixture circulates from bottom to top in the reactor-exchanger under conditions such that its residence time is limited to about 100 to 300 ms.

[0064] The cooling section 120 adapted to carry out quenching is connected to the evacuation means 118 of the exchange reactor 112.

[0065] In this embodiment, the cooling section includes a heat exchanger 122 receiving the gaseous effluent from the reactor-exchanger 112.

[0066] According to the invention, the installation further comprises a closed loop circuit 130 in which a working fluid circulates, this circuit being connected on the one hand to the inlet 1115 of the shell of the reactor-exchanger 112 and on the other hand to the corresponding outlet 116 of the shell.

[0067] This circuit 130 comprises in this embodiment:

[0068] two heating devices 131, 132 for the working fluid, here mounted in series and located upstream of the reactor-exchanger 112 with respect to the circulation of the working fluid,

[0069] a thermal storage system 170 coupled to the circuit 130 via a bypass pipe 172 and mounted downstream of the heating devices 131, 132, and upstream of at least one heat exchanger reactor 112,

[0070] two heat exchangers 134, 135, here mounted in series, located downstream of the reactor-exchanger 112 and upstream of the heating devices 131, 132,

[0071] a device for circulating the working fluid 138,

[0072] a management system 180 of the heating devices 131, 132 of the circuit and of the thermal storage device 170.

[0073] This management system 180 is configured, in particular programmed, to: (i) in a charging phase of the thermal storage system 170, operate the heating devices 131, 132 of circuit 130 to heat the working fluid to a target temperature, here 1200 °C, and accumulate heat within the thermal storage system 170, (ii) in a discharge phase of the thermal storage system 170: - circulate through the thermal storage system 170 all, or a fraction, of the working fluid flow circulating in the circuit 130 to heat it to the target temperature, or a first temperature, respectively - and stop at least one heating device 131, 132 of the circuit 130, or command it to heat to a second temperature the remaining fraction of the working fluid flow which, in mixing with the fraction of working fluid at the first temperature, reaches the target temperature.

[0074] Regardless of the embodiment of the closed-loop circuit and the number and arrangement of the heating device(s) and storage system(s) of said circuit, during the charging phase, heat can be accumulated within the thermal storage system in various ways. For example, a portion of the working fluid at the target temperature can be circulated through the thermal storage system. If the latter includes an electric heating device, this can optionally be used to further heat the working fluid. Alternatively, a portion of the working fluid taken from a point in the circuit where it is not at the target temperature, for example upstream of at least one of the heating devices, can be circulated through the thermal storage system and further heated by means of the electric heating device of the thermal storage system.Furthermore, when multiple thermal storage systems are present, they can accumulate heat in different ways, independently of each other.

[0075] It is also possible to configure the 180 management system to operate the thermal storage system in load mode when electricity is cheaper and / or comes from decarbonized sources (wind, solar, nuclear power plant, hydroelectricity, ...), which allows for the decarbonization of the installation's electricity consumption and / or a reduction in operating costs. This also applies to all embodiments described in this application.

[0076] The thermal storage system 170 typically comprises, or is made up of, one or more thermal storage devices, for example, one or more insulated enclosures, each containing a solid or liquid thermal storage medium. This system may optionally include one or more electric heating devices 176, integrated or not with the thermal storage devices. In this case, the electric heating device may be selected from a Joule heating device, a microwave heating device, a shock wave heating device, a plasma heating device, or an induction heating device.

[0077] The thermal storage medium (liquid or solid) advantageously has suitable thermal storage capacities and / or is capable of achieving suitable heat transfer rates for the desired use.

[0078] The solid thermal storage medium can be in the form of powders, particles, or solid blocks having cavities and / or open channels. Suitable heat-transfer solids include volcanic rocks or refractory materials, such as alumina, etc. A thermal storage device containing volcanic rocks produced by Brenmiller Energy can thus be used. Stacked refractory materials can also be used. The storage device can, for example, be similar to a glass furnace regenerator and contain a stack of refractory materials, these refractory materials being in the shape of cruciforms, bricks, bushels, or pots.Electrically conductive refractory bricks can also be used, which can be heated by the circulation of gas and / or by an electric current passing through the bricks during the charging of the thermal storage (for example, refractory bricks from Joule Hive Thermal Battery).

[0079] The liquid storage medium can advantageously be selected from ionic liquids, salts, for example potassium nitrate (KN03), calcium nitrate (Ca(NO3)2), sodium nitrate (NaNO3), sodium nitrite (NaNO2), lithium nitrate, alone or in mixtures, for example a mixture of sodium nitrate and potassium nitrate or a eutectic mixture of sodium nitrate and potassium nitrate, salt-water systems, in which the salts form hydrates, such as lithium bromide. Preferably, the liquid medium can be selected from salts, such as potassium nitrate, calcium nitrate, sodium nitrate, sodium nitrite, lithium nitrate, alone or in mixtures. For example, a eutectic mixture containing 60% by mass of sodium nitrate and 40% by mass of potassium nitrate (KN03), also called "Solar Salt", or a mixture containing 7% by mass of NaNO3, 53% by mass of KNO3 and 40% by mass of NaNO2, or a mixture containing 48% by mass of Ca(NO3)2, 45% of KNO3 and 7% of NaNO2.

[0080] The position of the thermal storage system(s) 170 in the circuit 130 can thus be chosen according to the temperature attainable by the thermal storage medium. For example, in the case of refractory brick storage that can be maintained at 1200 °C, the thermal storage system can be positioned downstream of the heating devices 131, 132, as shown [Fig. 1]. In the case of molten salt storage that can be maintained at a temperature of approximately 500 °C, the thermal storage system will be positioned further upstream, for example between the two heating devices 131, 132, or in parallel with the heating device(s) 131, 132.

[0081] A valve 174 can be positioned connecting the bypass line 172 to the circuit 130 to facilitate the management of the working fluid flow circulating in this bypass line during the charging and discharging phases. This valve 174 is ideally controlled by the management system 180.

[0082] The management system 180 used in the present invention typically comprises one or more processors, for example a microprocessor, a microcontroller, or the like. It can be configured (in particular programmed) to control the heating and thermal storage device(s) of the circuit 130, as well as the electric heating device(s) of the thermal storage system when present. It can thus be connected to these components, and optionally to one or more valve(s), fan(s), pump(s), or other element used for fluid circulation and flow regulation, and / or to the power supply of the components and / or to the control of these components.

[0083] The management system 180 can also receive various pieces of information from one or more appropriately arranged sensors relating to:

[0084] - to the power supply (electrical and / or thermal) of each device heating of circuit 130, and possibly of the thermal storage system (quantity of current received and consumed, temperature and / or flow rate of fluids whose temperature is controlled),

[0085] - in the charging and discharging state of each thermal storage system (temperature of thermal storage devices),

[0086] - to the phase in which each thermal storage system is located (charge, dump),

[0087] - to the amount of electrical and / or thermal energy received / produced by each electric heating device / thermal storage system (quantity of current, flow rate and / or temperature of fluids).

[0088] The management system 180 typically includes output or input / output interfaces. These may be wireless communication interfaces (Bluetooth, Wi-Fi, or other) or connectors (network port, USB port, serial port, FireWire® port, SCSI port, or other). These input and / or output interfaces may form means of communication, optionally bidirectional, between the management system and the circuit heating device(s) and the thermal storage system(s).

[0089] The management system 180 may also include storage means which may be random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, external memory, or other. These storage means may, among other things, store received data, measured values, calculated values, and one or more computer programs.

[0090] In the embodiment of [Fig. 1], the first heat exchanger 134 is used to heat steam to obtain a dilution steam suitable for mixing with the hydrocarbon feedstock to be steam cracked. For this purpose, this first heat exchanger 134 uses the heat from the working fluid circulating in the circuit 130 at the outlet 116 of the reactor-exchanger 112. The second heat exchanger 135 uses the residual heat from the working fluid exiting the first heat exchanger 134 to preheat the hydrocarbon feedstock before it is mixed with the dilution steam and this mixture enters the heat exchanger 122 of the cooling section.

[0091] In this embodiment, the first heating device 131 is an electric boiler and the second heating device 132 is an electric superheater.

[0092] The invention is not limited, however, by the number, nature, and arrangement of the heating devices, provided that the device(s) do not emit CO2. Preferred heating devices include electric heating devices that produce heat by Joule heating, microwaves, shock waves, plasma, and / or induction, as well as heat pump-type heating devices. Combustion heating devices using hydrogen (H2), the combustion of which produces only water, may also be used. Each device may be in the form of a boiler, furnace, or superheater. When several devices are present, they may be connected in series and / or in parallel.

[0093] In this embodiment, the working fluid circulation device 138 is a pump. However, the invention is not limited to this device, which will be chosen according to the nature of the working fluid. For example, a pump may be used when the fluid is liquid in one part of the circuit, and a compressor or a fan when the fluid is gaseous. More than one circulation device may be provided depending on the dimensions of the circuit 130. The working fluid may, in particular, be chosen from water, CO2, helium, nitrogen, or argon.

[0094] The embodiment of [Fig.1] is particularly suited to a working fluid which is water, and which will be in a liquid state in one part of the circuit (that where the pump 138 is located) and in a vapor state in the rest of the circuit 130.

[0095] The steam cracking of a hydrocarbon feedstock using the installation shown [Fig.1] is now described.

[0096] This steam cracking includes in particular a heating phase implemented in the heating section 110 under appropriate conditions, which delivers a hot steam cracking effluent, and a rapid cooling phase of said effluent implemented in the cooling section 120 under appropriate conditions.

[0097] Typically, at the inlet of the heating section 110, the temperature of the gas mixture can be from 600 to 680 °C. The temperature of the gas effluent at the outlet of the heating section 110 is typically from 800 to 900 °C. The residence time of the gas mixture in the heating section is short, typically from 100 to 300 ms. In the heating section, the gas mixture is, for example, maintained at a pressure of 1.5 to 3 bar.

[0098] This effluent contains unreacted raw materials and reaction products that vary depending on the nature of the feedstock to be cracked. For example, if the hydrocarbon feedstock to be cracked is naphtha, the effluent contains the desired olefins (mainly ethylene and propylene), hydrogen, methane, a C4 mixture (mainly isobutylene and butadiene), gasoline (aromatics in the C6 to C8 range), ethane, propane, acetylenes (acetylene, methylacetylene, propadiene), and heavier hydrocarbons with boiling points in the fuel oil temperature range. This effluent containing the cracked gases is rapidly cooled during the cooling phase, typically to 300–510 °C, to stop pyrolysis reactions and minimize secondary polymerization reactions.Depending on the average molecular mass of the feedstock, the relative quantities of the different products vary: for light feedstocks, such as ethane, there are few hydrocarbons with more than 4 carbons. The cooled effluent containing the cracked gases is then fractionated to separate the products of interest.

[0099] The working fluid follows the following path in the circuit 130. The pump 138 sends the working fluid, here liquid water, into the electric boiler 131 where steam is produced, for example here at a temperature of 225 °C and a pressure of 25 bar. Then, the working fluid (steam at 225 °C), during a charging phase of the thermal storage system 170, enters the superheater 132 and emerges superheated, for example at 1200 °C. A fraction of the flow of this superheated working fluid is then sent into the bypass line 172 via the valve 174 in order to pass through the storage system 170. During a discharging phase of the thermal storage system, it can be operated at idle speed. The operation of the superheater 132 is reduced or stopped, and the working fluid is circulated through the storage system 170 to superheat it. The superheated working fluid then enters the shell of the reactor-exchanger 112 through the inlet 115 and circulates within it. The superheated working fluid cools as it passes through the reactor-exchanger 112, transferring its heat to the reactor-exchanger tubes. The working fluid thus exits at a temperature lower than its inlet temperature, here approximately 700 °C. At the outlet of the reactor-exchanger, the working fluid is sent, for example directly, to the first heat exchanger 134. This heat exchanger receives steam, for example at 180 °C, from a line 1, which it heats, for example, to 500 °C. The dilution steam exiting the first exchanger 134 is evacuated by a pipe 2 which joins a pipe 4 in which the hydrocarbon charge circulates.Thus, the first heat exchanger 134 brings steam to a temperature suitable for use as dilution steam to be mixed with the hydrocarbon feedstock to be steam cracked before it enters the heat exchanger 122. The working fluid, cooled by its passage through the first exchanger 134, here at a temperature of approximately 200 °C, is then sent to the second heat exchanger 135 where it performs an initial preheating of the hydrocarbon feedstock supplied by a pipe 3. At the outlet of this second exchanger 135, the working fluid, here water, is again in a liquid state and returned by the pump 138 to the first heating device 131. The second heat exchanger 135 can, for example, heat naphtha from 60 °C to 120 °C (naphtha in vapor form), which is then mixed with steam. dilution at 500 °C exiting the first heat exchanger 304 of circuit 30.The resulting mixture can reach a temperature of approximately 300 °C and is then preheated to approximately 600 °C as it passes through the heat exchanger 122, which is used to quench the gaseous effluent. The gaseous mixture then enters the tubes of the reactor-exchanger 112 through inlet 113. These tubes are heated primarily by convection, to approximately the temperature of the working fluid circulating in the calender. The working fluid can flow in the same direction as the gaseous mixture in the tubes, which promotes a greater heat input at the very beginning of the reaction. The gaseous mixture thus undergoes a steam cracking reaction, producing a gaseous effluent exiting the reactor-exchanger 114 through outlet 114 and discharged via pipe 118 to the heat exchanger 122, where it is cooled by the gaseous mixture.At the outlet of the heat exchanger 122, a pipe 5 carries the cooled steam cracking effluent to the sections typically found in a steam cracking plant (not shown), allowing for the recovery of the products of interest. These... sections include cooling, compression, fractionation sections, well known to those skilled in the art and which will not be detailed further.

[0100] The invention is of course not limited by the nature of the hydrocarbons that can be steam cracked. The installation and the process according to the invention can thus be implemented for the steam cracking of various hydrocarbon feedstocks of fossil origin such as ethane, liquefied petroleum gases (propane, butane), naphtha, diesel and vacuum distillate, of various hydrocarbon feedstocks of biological origin, such as ethane, propane, butanes, naphtha and distillates produced during the hydrotreating / hydrocracking of fatty acid esters (for example triglycerides), biomass pyrolysis oils and / or biomass hydrothermal liquefaction oils, or even other hydrocarbon feedstocks obtained by pyrolysis, hydrothermal liquefaction and / or hydrocracking of plastic waste.

[0101] The embodiment of [Fig. 2] differs from that of [Fig. 1] primarily in the cooling section 120, the preheating of the hydrocarbon feed, and the number of thermal storage systems. In this embodiment, the cooling section 120 comprises a first heat exchanger 124 and a second heat exchanger 126 connected in series: the effluent exiting the reactor-exchanger 112 through outlet 114 and line 118 first passes through the first heat exchanger 124 and then the second heat exchanger 126 before being sent via line 5 to the fractionation section (not shown). The installation 100 further comprises a preheating heat exchanger 140 connected by another closed-loop circuit 142 to the first heat exchanger 124 of the cooling section. The working fluid circulating in this circuit 142 is water here but could be one of the working fluids mentioned for circuit 130.This preheating heat exchanger 140 receives the preheated hydrocarbon feed from the second heat exchanger 135 of circuit 130, for example at a temperature of 120 °C, and heats it further before sending it through line 4 into the second heat exchanger 126 of the cooling section.

[0102] This embodiment differs from the previous one essentially by the cooling of the effluent exiting the heating section 110 and by the preheating of the components of the gas mixture. The working fluid circulates in the circuit 130 as described with reference to [Fig. 1].

[0103] In this embodiment, two thermal storage systems 170, 170' are provided. A first thermal storage system 170 is arranged as in the embodiment of [Fig. 1]. The second thermal storage system 170' is mounted in parallel with the second heating device 132. For this purpose, its bypass line 172' is connected on the one hand, via a valve 174', to the part of the circuit 130 connecting the two heating devices 131, 132, and on the other hand to the part of the Circuit 130 is located between the second heating device 132 and the first thermal storage system 170. The second thermal storage system 170' may also include an electric heating device 176', integrated or not. In this case, during the charging phase, a fraction of the working fluid flow will be circulated through each storage system 170, 170' to accumulate heat. During the discharging phase, each of the thermal heating devices 131, 132 can then be operated at reduced capacity, or shut down, while part or all of the working fluid flow circulating in circuit 130 passes through the two thermal storage systems 170, 170'.

[0104] In this embodiment, the effluent exiting the reactor-exchanger 112 through the pipe 118 is first cooled in the first exchanger 124 by the cold working fluid circulating in the loop 142, here water in the liquid state. During its passage through this first heat exchanger 124, the water from circuit 142 vaporizes into high-pressure water vapor, for example at 325 °C and 120 bar, and returns to the preheating heat exchanger 140 in which it preheats the hydrocarbon feed, here a naphtha, which has been previously heated (vaporized) from about 60 °C to about 120 °C in the second heat exchanger 135 of circuit 130. The preheated hydrocarbon feed exiting the preheating heat exchanger 140 via line 4 then joins line 2 in which the dilution water vapor exiting the first heat exchanger 134 of circuit 130 circulates.The resulting gas mixture is then sent to the second heat exchanger 126 of the cooling section 120 in which it is heated to approximately 600 °C by the partially cooled effluent from the first heat exchanger 124 of the cooling section 120.

[0105] The embodiment of [Fig. 3] differs from that of [Fig. 1] essentially by the circuit 130 supplying the hot working fluid to the heating section 100 and by the preheating of the hydrocarbon charge. Furthermore, in this embodiment, a single temperature storage system 170 is mounted in parallel with the heating device 133 of the circuit 130.

[0106] In this embodiment, the circuit 130 comprises:

[0107] a heating device 133 for the working fluid, located upstream of the reactor-exchanger 112 with respect to the working fluid circulation,

[0108] two heat exchangers 134', 135', here mounted in series, located downstream of the reactor-exchanger 112 and upstream of the heating device 133,

[0109] a device for circulating the working fluid 139.

[0110] Unlike the embodiment of [Fig.1], in this embodiment, the first heat exchanger 134' of the circuit is used to preheat the working fluid of the circuit 130 before it enters the heating device 133 using the hot working fluid exiting, in particular directly, from the reactor-exchanger 112. Furthermore, the second heat exchanger 135' serves to preheat water supplied via a pipe 10, which is then conveyed via a pipe 11 to a preheating heat exchanger 150 of the installation, where it is vaporized under suitable conditions to form dilution steam. This preheating heat exchanger 150 uses for this purpose some of the residual heat from the effluent exiting the heat exchanger 122 of the cooling section 120 via the pipe 5. The preheating of the hydrocarbon feed supplied via the pipe 3 is finally carried out by means of a second preheating heat exchanger 160, which uses for this purpose the residual heat from the cooled effluent exiting the first preheating heat exchanger 150.The cooled effluent is discharged from the preheating heat exchanger 160 via a pipe 12, then conveyed to the usual subsequent cooling, compression, and fractionation sections to recover the products of interest.

[0111] In this embodiment, the working fluid circulation device 139 is a compressor or fan, this embodiment being more particularly suited to a gaseous working fluid, here CO2.

[0112] Thus, in this embodiment, the working fluid follows the following path in the circuit 130. The compressor 139 sends the working fluid to the heat exchanger 134' where it is preheated by the hot working fluid exiting the reactor-exchanger 112 through outlet 116. The preheated working fluid is then further heated in the heating device 133 and / or in the thermal storage system 170 before entering the reactor-exchanger 12 through inlet 115, where it transfers heat to the tubes for the implementation of the steam cracking reaction. Upon exiting the reactor-exchanger 112, the working fluid first passes through the first heat exchanger 134' before being conveyed to the second heat exchanger 135' where it is used to heat water. It is then returned by compressor 139 to the first heat exchanger 134'.

[0113] In the embodiment shown here, during the charging phase of the thermal storage system, a fraction of the working fluid flow circulating in circuit 130 can be sent through the thermal storage system 170 so that it accumulates heat. Depending on the temperature of this fraction, the electric heating device of the thermal storage system can be switched on to reach a desired thermal storage temperature. During the discharging phase, depending on this thermal storage temperature, either the entire working fluid flow can be circulated through the thermal storage system 170 to heat it to the desired target temperature, with the heating device 133 of the circuit being off, or a fraction of the working fluid flow can be circulated through the thermal storage system 170 to heat it to a first temperature, and operate the heating device 133 of the circuit to heat the remaining fraction of working fluid flow to a second temperature, which, by mixing with the fraction of working fluid at the first temperature, reaches the target temperature.

[0114] The hydrocarbon feedstock is first preheated by the second preheating heat exchanger 160 using the residual heat from the effluent exiting the first preheating heat exchanger 150. At the outlet of the second preheating heat exchanger 160, the hydrocarbon feedstock is mixed with dilution steam produced by the first preheating heat exchanger 150 using the residual heat from the effluent exiting the heat exchanger 122 of the cooling section. The resulting gaseous mixture is then further heated in this heat exchanger 122 before entering the reactor-exchanger tubes 112 through the inlet 113, where the steam cracking reaction takes place.At the outlet of reactor-exchanger 112, the hot effluent is rapidly cooled in heat exchanger 122, then further cooled in preheating heat exchangers 150 and 160, which respectively heat dilution steam and the hydrocarbon feedstock.

[0115] In this third embodiment, one or more heating devices 133 connected in series and / or parallel may be provided to heat the working fluid. Preferably, this heating device does not emit CO2 and may be as described above. If water is used as the working fluid, the heating devices described with reference to [Fig. 1] may be used.

[0116] In the various embodiments, other arrangements of one or more heating devices may nevertheless be provided, provided that they enable the working fluid to be heated to a target temperature sufficiently high so that the gas mixture circulating inside at least one heat exchanger-reactor reaches the desired reaction temperature. Those skilled in the art can determine this target temperature through tests and / or modeling, based on the feedstock to be steam cracked and the characteristics of the heat exchanger-reactor.

[0117] It should also be noted that the preheating of the hydrocarbon feed as described with reference to [Fig. 2] can also be implemented in the embodiment of [Fig. 3]. In this case, the preheating heat exchanger 140 described with reference to [Fig. 2] is arranged immediately downstream of the second preheating heat exchanger 160.

[0118] In the embodiments described above, the circuit 130 comprises two heat exchangers. However, the invention is not limited to this preferred embodiment, and a single heat exchanger, or more than two heat exchangers, may be provided.

[0119] The various embodiments of the heating and thermal storage devices of the circuit described above can be combined according to the desired objective. In particular, during the discharge phase, when a fraction of the working fluid is heated to a first temperature and the remaining fraction is heated to a second temperature, those skilled in the art can determine, through testing and / or modeling, each temperature as a function of the flow rates so that all of the working fluid entering at least one heat exchanger-reactor reaches the desired target temperature. Generally, thermal storage systems will be chosen that enable the desired target temperature of the working fluid at the inlet of at least one heat exchanger-reactor 112 to be reached, whether or not in combination with the circuit heating device(s).It is therefore understandable that it is possible to consider many different arrangements of these devices and systems (parallel and / or series connections), and / or continuous operation with periods of reduced activity and / or temporary shutdown of the heating device(s).

[0120] The present invention thus consists of using the working fluid as a heat transfer fluid (such as CO2, steam, argon, helium, etc.) which is heated by a CO2-free heating device to a target temperature, typically above 900 °C, generally under increased pressure (>20 bar), and sent to a heat exchanger reactor, preferably to its shell, where it exchanges heat, preferably with the tubes in which the steam cracking reaction takes place. Subsequently, the heat transfer fluid, having lost temperature, is used to vaporize and / or preheat the feedstock, the dilution steam, or both, and is finally recovered at a reduced temperature and pressure (due to the pressure drop on the heat exchanger equipment).This heat transfer fluid at reduced temperature and pressure is repressurized by compression or pumping (in case of fluid condensation), and reheated using the heating device to the target temperature to close the cycle.

[0121] The invention thus offers the following advantages:

[0122] A decarbonization of the steam cracking of hydrocarbons to manufacture basic chemicals using one or more heating devices that do not emit CO2, and preferably using renewable electricity, without emitting greenhouse gases,

[0123] improved control of the skin temperature of the tubes in the heat exchanger reactor, making it possible to limit coking,

[0124] a compact installation, a heat exchanger reactor being much more compact than the combustion furnaces usually used, because the heat exchange occurs primarily through high-pressure convection, which requires significantly less volume, particularly on the grille side.

[0125] optimized management of energy consumption required for heating the working fluid through the use of thermal storage system(s).

Claims

1. Demands Steam cracking plant (100) comprising: - at least one shell and tube heat exchanger reactor (112), each heat exchanger reactor comprising means for supplying (117) a suitable gaseous mixture comprising at least one hydrocarbon, connected to an inlet selected from an inlet (113) of the tubes and an inlet (115) of the shell, and means for discharging (118) a hot gaseous effluent connected to a corresponding outlet (114, 116) of the tubes or the shell, - a cooling section (120) adapted for quenching, connected to the discharge means of each heat exchanger reactor, characterized in that it further comprises: - at least one closed-loop circuit (130) in which a working fluid circulates, this circuit being connected on one side to the other inlet of at least one heat exchanger reactor chosen from an inlet (113) of the tubes and an inlet (115) of the shell, and on the other side to the corresponding outlet (114, 116) of the tubes or the shell, each circuit (130) comprising: - at least one heating device (131, 132; 133) for the working fluid located upstream of at least one heat exchanger reactor (112) with respect to the working fluid circulation, - at least one thermal storage system (170, 170') coupled to the circuit (130) in a closed loop via a bypass pipe (172, 172'), and mounted in parallel with or downstream of at least one heating device (131, 132; 133), and upstream of at least one heat exchanger reactor (112), - at least one heat exchanger (134, 135; 134', 135') located downstream of at least one heat exchanger reactor (112) and upstream of at least one heating device (131, 132; 133), - at least one working fluid circulation device (138, 139), - a management system (180) for at least one heating device (131, 132; 133) of the closed-loop circuit (130) and for at least one thermal storage device (170, 170'), configured to: (i) in a charging phase of at least one thermal storage system (170, 170'), operate at least one heating device (131, 132; 133) of said circuit to heat the working fluid to a target temperature, and accumulate heat within the at least one thermal storage system, (ii) in a discharging phase of at least one thermal storage system (170, 170'): - circulate through the at least thermal storage system (170, 170') all, or a fraction, of the working fluid flow circulating in said circuit to heat it to the target temperature, or to a first temperature, respectively, - and stop at least one heating device of said circuit, or command it to heat to a second temperature the remaining fraction of the working fluid flow which, in mixing with the fraction of working fluid at the first temperature, reaches the target temperature.

2. Steam cracking plant (100) according to claim 1, characterized in that at least one thermal storage system (170, 170') comprises one or more thermal storage devices each containing a solid or liquid thermal storage medium, and optionally one or more electrical heating devices (176, 176').

3. Steam cracking installation (100) according to claim 1 or 2, characterized in that at least one closed loop circuit (130) comprises at least two heating devices for said circuit (130) mounted in series and / or in parallel.

4. Steam cracking installation according to any one of the preceding claims, characterized in that at least one heating device of said circuit (130) is selected from a Joule effect heating device, a microwave heating device, a shock wave heating device, a plasma heating device, an induction heating device, a heat pump, a hydrogen furnace.

5. Steam cracking plant according to any one of claims 1 to 4, characterized in that the cooling section (120) comprises a heat exchanger (122) connected on the one hand to the exhaust means (118) of at least one heat exchanger reactor (112) and on the other hand to the means supplying (117) at least one heat exchanger reactor so as to preheat the gas mixture entering the latter by means of the gaseous effluent exiting the latter, and in that this heat exchanger (122) is connected to at least one heat exchanger (134, 135) of said circuit (130) to receive at least one constituent of the preheated mixture.

6. Steam cracking installation according to any one of claims 1 to 5, characterized in that the at least one closed-loop circuit (130) comprises a first (134) and a second (135) heat exchangers mounted in series downstream of the at least one heat exchanger reactor (112), the first heat exchanger (134) being connected to a water supply line (1) and adapted to heat it, and the second heat exchanger (135) being connected to a supply line (3) for a component of the gas mixture and adapted to preheat it before its entry into the at least one heat exchanger reactor (112) or before its entry into a heat exchanger (122) of the cooling section.

7. Steam cracking installation (100) according to any one of claims 1 to 4, characterized in that the at least one closed-loop circuit (130) comprises a first (134') and a second (135') heat exchangers mounted in series downstream of the at least one heat exchanger reactor, the first heat exchanger (134') being connected to the circuit (130) on the one hand upstream of the at least one heating device (138, 139), and downstream of the second heat exchanger (135'), and on the other hand downstream of the at least one heat exchanger reactor (112) and upstream of the second heat exchanger (135'), the second heat exchanger (135') being connected to a water supply line (10) and adapted to preheat this water by means of the working fluid.

8. Steam cracking plant (100) according to claim 7, characterized in that: - the cooling section (120) comprises a heat exchanger (122) connected on the one hand to the exhaust means (118) of at least one heat exchanger reactor and on the other hand to the feed means (112) of at least one heat exchanger reactor so as to preheat the gas mixture entering the latter by means of the gaseous effluent exiting the latter, and - the installation also includes at least two preheating heat exchangers (150, 160): the first preheating heat exchanger (150) being connected on one side to the heat exchanger (122) of the cooling section to receive the cooled gaseous effluent and on the other side to the second heat exchanger (135') of the closed-loop circuit (130) to further heat and vaporize the water exiting the latter, the second preheating heat exchanger (160) being connected on the one hand to the heat exchanger (122) of the cooling section to supply it with a constituent of the heated gas mixture and on the other hand to the first preheating heat exchanger (150) to receive the further cooled gaseous effluent.

9. Steam cracking plant (100) according to any one of claims 1 to 5, characterized in that the cooling section comprises a first and a second heat exchanger mounted in series: the first heat exchanger (124) being connected on the one hand to the evacuation means (118) of at least one heat exchanger reactor (112) and on the other hand to a preheating heat exchanger (140) located upstream of at least one heat exchanger reactor (112) with respect to the circulation of the fluids, so as to preheat a constituent of the gas mixture, the second heat exchanger (126) being connected on the one hand to the first heat exchanger (124) and on the other hand to the preheating heat exchanger (140) and to at least one heat exchanger (135) of the closed loop circuit (130), to receive at least one constituent of the preheated mixture.

10. A steam cracking process for a gaseous mixture of a hydrocarbon feedstock and steam, suitable for implementation by a steam cracking plant according to any one of the preceding claims, said process comprising a heating phase in a heating section under suitable conditions, which delivers a hot steam cracking effluent, and a rapid cooling phase of said effluent in a cooling section (120) under suitable conditions, and recovers said cooled steam cracking effluent, characterized in that: - the gas mixture, preferably preheated, is introduced into at least one pressure shell and tube heat exchanger reactor (112) via an inlet of the latter chosen from an inlet (113) of the tubes and an inlet (115) of the shell, and the gas mixture is circulated inside the tubes or the shell of said heat exchanger reactor (112), - the heating phase of the gas mixture in the at least one heat exchanger reactor (112) is carried out according to the following steps: (a) A working fluid is circulated within a closed-loop circuit (130), this circuit being connected on one side to the other inlet of at least one heat exchanger reactor selected from an inlet (113) of the tubes and an inlet (115) of the shell, and on the other side to the corresponding outlet (114, 116) of the tubes or the shell, and said working fluid is heated to a target temperature higher than the temperature to which the gas mixture is to be heated by means of at least one heating device (131, 132; 133) of said circuit (130) and / or by means of at least one thermal storage system (170, 170') of said circuit (130) as follows: (i) in a charging phase of at least one thermal storage system (170, 170'), at least one heating device (131, 132) is operated ;133) said circuit (130) to heat the working fluid to the target temperature, and calories are accumulated within at least one thermal storage system,; (ii) in a discharge phase of at least one thermal storage system (170, 170'): - the entirety, or respectively a fraction, of the working fluid flow circulating in said circuit is circulated through at least one thermal storage system to heat it to the target temperature, or respectively to a first temperature, - and at least one heating device (131, 132; 133) of said circuit (130) is stopped, or it is controlled to heat to a second temperature the remaining fraction of the working fluid which, in mixing with the fraction of working fluid at the first temperature, reaches the target temperature, (b) the working fluid is introduced at the target temperature into the heat exchanger reactor, the cooled working fluid is recovered and reinjected into the closed loop circuit (130) upstream of at least one heating device of said circuit, and a hot steam cracking effluent is recovered and sent immediately to the cooling section.

11. Method according to claim 10, characterized in that, at least one storage system (170, 170') comprising at least one electric heating device, during the charging phase, it can be operated to accumulate calories, and optionally stopped during the discharging phase.

12. A process according to claim 10 or 11, characterized in that it comprises at least one of the following features: - the working fluid is selected from water, CO2, helium, nitrogen or argon, - the target temperature of the working fluid is from 900 to 1600 °C, preferably from 1000 to 1400 °C, - the pressure of the working fluid is from 30 barg to 80 barg.

13. A method according to any one of claims 10 to 12, characterized in that the gaseous effluent having circulated in at least one heat exchanger reactor (112) is recovered and sent to at least one heat exchanger (122; 124, 126) of the cooling section (120) to cool it rapidly and preheat the gaseous mixture before it enters at least one heat exchanger reactor (112).

14. A method according to any one of claims 10 to 12, characterized in that the working fluid having circulated in at least one heat exchanger reactor (112) is recovered and sent to at least one heat exchanger of the closed-loop circuit (130) in which at least one fluid selected from (i) at least one constituent of the gas mixture is preheated before its entry into at least one heat exchanger reactor or before its entry into at least one heat exchanger of the cooling section (120), (ii) water, (iii) steam, and (iv) the working fluid before its entry into at least one heat exchanger reactor (112).

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