Process for steam cracking

Abstract

The present invention relates to a method for cracking a hydrocarbon feedstock using an electric power plant to the maximum extent possible, wherein the electric power comes from a renewable source or a low-carbon source. In particular, the present invention relates to a method for cracking a hydrocarbon feedstock, the method comprising subjecting the hydrocarbon feedstock and dilution steam to supersonic speed in a reactor, followed by applying a shock wave to induce cracking of the hydrocarbon feedstock to convert at least a portion of the hydrocarbon mixture to produce olefins.

Description

[0001] introduce

[0002] The present application relates to a process for cracking a hydrocarbon feedstock using maximum utilization of an electrical power plant, wherein the electricity is obtained from a renewable source or a low carbon source.

[0003] Global warming and climate change, caused by human emissions of greenhouse gases, have become a major issue of public concern. Major policy initiatives such as the Paris Climate Agreement in 2017 and the European Green Deal in 2019 require actions to reduce emissions from all sectors of society, including the chemical industry.

[0004] The chemical industry is a major source of greenhouse gas emissions, either through the generation of the energy required for its conversions by combustion, through the emission of by-products or through the end-of-life incineration of its products.

[0005] A particularly large source of greenhouse gas emissions is concentrated in several large-scale processes carried out at high temperatures (above 500°C) that require external heating by the combustion of fossil hydrocarbons. Examples are steam cracking (producing light olefins from crude oil, distillates such as naphtha or gases such as ethane, propane and butane), catalytic cracking (producing light components for fuel or feedstock use from heavy petroleum fractions) and methane steam reforming (producing hydrogen and carbon monoxide or carbon dioxide from natural gas).

[0006] Conventional steam crackers are complex industrial facilities that can be divided into three main sections, each with several types of equipment having very specific functions: (i) the hot section, including: pyrolysis or cracking furnaces, quench exchangers and quench circuits, columns of the hot separation train; (ii) the compression section, including: cracked gas compressors, purification and separation columns, dryers; and (iii) the cold section, including: cold boxes, demethanizers, fractionation columns of the cold separation train, C 2 and C 3 Converter, gasoline hydrogenation stabilization reactor.

[0007] Conventional steam cracking is carried out in a tubular reactor in a direct fired heater (furnace). Various tube sizes and configurations can be used, such as spiral tubes, U-tubes, or straight tube layouts. Tube diameters range from 1 to 4 inches. Each furnace consists of a convection zone where waste heat is recovered and a radiant zone where pyrolysis occurs.

[0008] To reduce or even eliminate greenhouse gas emissions from these processes, using renewable or low-carbon energy sources, especially electricity, to achieve these high temperatures would be an important step forward. This is not unheard of: many examples of industrial heating with electricity are known, such as the use of electric arc furnaces to melt scrap metal or produce phosphorus, or for pipeline tracing. However, the easy availability and low cost of fossil fuels in the petrochemical industry (where they are often a side stream of certain conversions) have prevented the widespread use of electric heating technology in large facilities.

[0009] Recent emphasis on reducing greenhouse gases has led to research into such electric heating methods. US20150321912 of BASF describes a method that uses electricity as a heat source, among other things. The '912 publication relates to a method for performing a heat consumption process, wherein the total energy required for the heat consumption process on average for one year comes from at least two different energy sources, one of which is an electrical energy source, whose power varies in the range of 0 to 100% of the required total power, and three different energy modes can provide the total power required for the heat consumption process, respectively: (i) pure electrical energy, (ii) a mixture of electrical energy and at least one other non-electrical energy source, or (iii) pure non-electrical energy, wherein the conversion time from one energy mode to another energy mode does not exceed 30 minutes.

[0010] Linde (US20170130887) relates to the use of resistive electric heating for a range of high temperature processes including steam cracking. It describes a device for heating a fluid, the device comprising at least one electrically conductive pipe for containing the fluid, and at least one voltage source connected to the corresponding pipe. The voltage source is designed to generate an electric current in the connected pipe, which heats the pipe and thereby heats the fluid.

[0011] Patents EP3249027 and EP3249028 envisage that at least one tubular reactor will be heated both by using the heat of combustion generated by burning at least one fuel and by using electrical heat generated by electrical energy.

[0012] US20180243711 (Haldor Topsoe) describes the use of inductive electric heating for many high temperature processes such as steam methane reforming. It relates to a reactor system for performing an endothermic catalytic chemical reaction within a given temperature range when a reactant is contacted with a catalyst material. The reactor system includes a reactor unit arranged to accommodate a catalyst material, the catalyst material including one or more ferromagnetic macroscopic carriers sensitive to inductive heating, wherein the one or more ferromagnetic macroscopic carriers are ferromagnetic at a temperature up to the upper limit of a given temperature range. The one or more ferromagnetic macroscopic carriers are coated with an oxide, and the oxide is doped with catalytically active particles. In addition, the reactor system includes an induction coil, which is arranged to be powered by a power supply supplying an alternating current and is positioned so as to generate an alternating magnetic field in the reactor unit when energized by the power supply, thereby heating the catalyst material to a temperature within the temperature range by the alternating magnetic field.

[0013] WO2016001476 (Coolbrook) describes a shock wave reactor for thermal cracking of hydrocarbon-containing feedstocks, the shock wave reactor comprising: a housing in which a conduit having an inlet and an outlet is formed; a rotor, the periphery of which contains an axial flow blade cascade; wherein the housing substantially surrounds the periphery of the rotor and a plurality of fixed blade cascades within the conduit, and further wherein the cascade is configured to guide a process flow containing the feedstock to repeatedly pass through the cascade in a spiral trajectory while propagating between the inlet and the outlet within the conduit, and to generate standing waves to heat the feedstock. The axial flow rotor cascade is configured to provide kinetic energy and increase the velocity of the process flow containing the feedstock, and the fixed blades located downstream of the rotor cascade are configured to reduce the velocity of the flow and convert the kinetic energy into heat. The reactor can be configured to implement a thermal cracking process utilizing hydrocarbons.

[0014] Although all these documents demonstrate a strong interest in greenhouse gas-free high-temperature processes, none of these have been implemented or demonstrated on an industrial scale in steam cracking processes.

[0015] Specific instructions

[0016] Steam cracking involves exposing hydrocarbon feedstocks (crude oil, gas oil, naphtha, ethane, propane, butane) to very high temperatures (750°C-1000°C) for very short periods of time (less than 1 second). During this very short period of time, the feedstock is thermally decomposed into useful products such as ethylene, propylene, butadiene and benzene. Longer exposure times cause undesirable continuous reactions, thereby reducing the yield of useful products and causing reactor contamination.

[0017] In the hot zone as described above, current reactor arrangements consist of narrow metal tubes in which the hydrocarbon feedstock diluted with steam passes at high velocity, wherein the tubes are externally heated by the combustion of light hydrocarbons (usually produced as a by-product of cracking) in a so-called firebox. The external flame heats the plurality of metal tubes essentially by radiation, while the still hot flue gases leaving the radiation zone pass through a heat exchange tube bundle to preheat the feedstock and dilution steam in the convection section.

[0018] In fact, the contact times and temperatures achieved in current equipment do not necessarily represent the most desirable combination of pressure, temperature and residence time from the point of view of product composition (which should be understood as the total product value). Shorter residence times and higher temperatures are unattainable in view of the speed of heat transfer. Higher temperatures require longer heat transfer and also hotter tube walls, both of which lead to more side reactions. And shorter residence times require even higher heat transfer rates. Classical technology heats in an uneven manner, creating hot spots that promote undesired conversions.

[0019] One way to further improve the efficiency of steam cracking is to apply different heat transfer techniques, either alone or in combination. More specifically, this concerns heating techniques that do not rely on heat transfer from hot metal surfaces to the hydrocarbon reaction mixture.

[0020] In addition to further optimizing current steam cracker practices, another important driver for change has also become a reality, namely the need to reduce greenhouse gas emissions in general, and the very high emissions from heating in large steam crackers in particular. Since the main supply of carbon-neutral energy is most likely to be naturally generated (electricity generated from nuclear, biomass, tidal and wave, geothermal, solar and wind sources), priority should be given to electrical technologies.

[0021] A particular technique for this is direct heating of hydrocarbon feedstock molecules by radiation induced by plasmas that interact directly with the molecules. This has been described for microwave radiation (Fall et al., "Microwave Enhanced cracking of ethane to ethylene production", AICHE Spring National Meeting, Houston, 2012). In fact, plasma conversion has been used industrially for many years in high-temperature processes (for a review, see Fincke et al., "plasmathermal conversion of methane to acetylene", Plasma Chemistry and plasma processing 22, 105-136 (2002). Some types of electromagnetic radiation (infrared, microwave, radio frequency) show direct interactions with hydrocarbons, but no practical applications for high-temperature heating have been described. And high-frequency changing electromagnetic fields can heat molecules through dipole interactions.

[0022] Another technique involves uniform heating of the gas by first accelerating the preheated gas to supersonic speeds and then rapidly decelerating it, thereby creating a shock wave in which near-instantaneous uniform heating to cracking temperatures occurs without the presence of a uniformly hotter surface (which would lead to undesirable side reactions).

[0023] In 2010, van Goethem described in his paper Next Generation Steam Cracker Concept the principle of cracking by induced shock waves, in which a hydrocarbon feedstock is injected into a carrier gas moving at supersonic speeds and subsequently decelerated. In this case, no preheating and acceleration methods were specified, and the possibility of full electrification (and the consequent elimination of carbon emissions) was not mentioned.

[0024] Rockwell International Corp (US4724272) describes a shock wave reactor for pyrolyzing methane. Fuel and oxidant are burned in a combustion zone to produce a hot gas stream at superatmospheric pressure. The hot gas stream is then passed through a convergent-divergent nozzle to accelerate the hot gas stream to a speed of at least about Mach 2. The reactants to be pyrolyzed are injected into the supersonic hot gas stream to produce a reaction mixture flowing at a supersonic speed and to initiate an endothermic pyrolysis reaction. Substantially thereafter, the velocity of the reaction mixture is reduced within a predetermined reaction time to convert the kinetic energy of the reaction mixture into thermal energy in an amount sufficient to substantially compensate for the endothermic reaction that occurs while maintaining supersonic flow. At the end of the predetermined reaction time, the velocity of the reaction mixture is reduced to a subsonic flow, and the reaction is quenched.

[0025] US5219530 (University of Washington) relates to an apparatus for initiating pyrolysis of a feedstock by establishing a continuous standing shock wave. A shock wave reactor receives an ethane feedstock and a carrier fluid including superheated steam. The feedstock and the carrier fluid are pressurized so that they expand into parallel supersonic flows that mix due to turbulence in a mixing section of a longitudinally extending channel of the shock wave reactor. The pyrolysis vessel includes a nozzle section disposed between an inlet and an outlet, the nozzle section having a cross-sectional area reduced compared to the cross-sectional area of ​​an adjacent portion of the pyrolysis vessel receiving the carrier fluid, and a plurality of injection nozzles receiving the feedstock behind the reduced cross-sectional area. The carrier fluid heats the ethane feedstock when mixed with the ethane feedstock, producing a mixture that flows longitudinally along the channel at a supersonic speed. A gate valve disposed downstream of the channel provides a controlled back pressure that affects the position of the shock wave and the residence time of the reaction. The shock wave rapidly heats the mixture to above the pyrolysis temperature, producing the desired product by cracking the feedstock. The rapid heating of the mixture results in a residence time of only 5 to 50 milliseconds in the pyrolysis section.

[0026] Other publications describing the heating of the cracking process using shock waves are US5300216; US20160296904A1; US20180215615A1 and US10384180B2. All publications describe the injection of the hydrocarbon feedstock into a hot carrier gas, which is usually produced by combustion of the feedstock.

[0027] In WO2019 / 221726A1 of Dresser Rand Company, a similar process and reactor configuration are described. In this case, hydrocarbon gas is accelerated to supersonic speeds by an electrically driven compressor and then decelerated in a static diffuser, causing shock waves, temperature spikes, and cracking. The process is not yet fully electrified, which can be achieved by electrification of the preheating as described in this patent application.

[0028] The Finnish company Coolbrook provides another variant based on the earlier Russian patents of Bushev (CN1298439A, CN102427875A). In this concept (rotational dynamics), the hydrocarbon feedstock is accelerated and decelerated in multiple stages in a blade reactor for hydrocarbon pyrolysis (EP2412430A4).

[0029] In all these claims, the emphasis is on combining high yields of valuable products (especially ethylene) with low production of undesirable by-products (such as coke) compared to conventional steam cracking. No mention is made of the possibility of reducing greenhouse gas emissions through complete electrification.

[0030] The embodiments disclosed in this application aim to eliminate as much carbon dioxide emissions as possible in industrial steam cracking by applying shock wave technology in the cracking section in combination with electrical preheating of the feedstock.

[0031] Therefore, an embodiment of the present application provides a method for cracking a hydrocarbon feedstock according to claim 1 .

[0032] As mentioned above, methods of applying shock waves to hydrocarbon feedstocks are known.

[0033] In subsonic aerodynamics, the phenomenon of flow heating by compression and dissipation is usually neglected. However, when supersonic speeds are reached in the flow, shock waves occur, which are particularly associated with an increase in the temperature of the fluid. This aerodynamic heating can increase the temperature of the electrically preheated reaction mixture at a temperature still below the initial cracking temperature by converting the kinetic energy of the molecules into heat without the need for heat transfer via the reactor wall, so as to quickly reach the initial cracking temperature.

[0034] The physical mechanism behind aerodynamic heating using shock waves can be explained as follows (Anderson, John D. (2007). Fundamentals of Aerodynamics (4th edition), McGraw-Hill.): Supersonic molecules that are decelerated in the diffuser section or by colliding objects experience a change in momentum; this change is transmitted to neighboring molecules at the local speed of sound. The upstream flow is supersonic and disturbances (pressure pulses or sound waves) cannot propagate upstream, so they pile up and merge to form standing waves. This shock wave is an extremely thin area at right angles to the flow direction of high gradient, on both sides of which the flow characteristics change dramatically. These sudden, almost discontinuous changes are characterized by the Rankine-Hugoniot jump relations, which explain the connection between the upstream and downstream velocities, pressures, temperatures, and densities of the shock wave. The speed of sound in the fluid can be expressed as a = (γRT) 0.5 , where γ = Cp / Cv is the specific heat ratio, R is the gas constant, and T is the temperature.

[0035] The Mach number of a flow is defined as the ratio of the local gas velocity to the speed of sound, and therefore, if the local gas speed of a flow is greater than its local speed of sound, or M>1, the flow is supersonic. The shock wave relationship is obtained by applying the laws of conservation of mass, momentum, and energy, from which three equations can be derived that give the ratio of density, velocity, and temperature on either side of a normal shock wave in terms of the pressure ratio on either side of the shock wave. The pressure ratio is often referred to as the strength of the shock wave. The second law of thermodynamics requires that for an adiabatic process, entropy must either remain constant or must increase, and therefore, accordingly, a shock wave must always be compressive, i.e., pressure must always increase across the shock wave. Using equations for the changes on either side of a normal shock wave, it is shown that density always increases, velocity always decreases, and temperature always increases across the shock wave. These equations can also be expressed in terms of the upstream and downstream Mach numbers of the shock wave. The conditions for achieving a compression shock wave (increase in entropy) dictate that the upstream Mach number must be supersonic (M>1) and the downstream Mach number must be subsonic (M<1).

[0036] In the case of a normal shock wave, the velocities upstream and downstream of the shock wave are both at right angles to the shock wave. In the case of an oblique shock wave, the flow direction changes on either side of the shock wave. More complex shock waves may be actually normal in parts of the flow, curved in other parts of the flow, and actually oblique in other parts of the flow. Without wishing to be bound by any theory, shock wave or aerodynamic heating may be achieved by decelerating the supersonic flow to a subsonic regime by applying a turning diffuser section, by placing a blunt body or concave body (wedge or cone) in the supersonic flow, or a combination of the latter.

[0037] The present application also provides additional embodiments according to claims 2 to 17 .

[0038] The feedstock for this process can be ethane, liquefied petroleum gas, naphtha or gas oil or a mixture thereof. Liquefied petroleum gas (LPG) consists essentially of propane and butane. Petroleum naphtha or naphtha is defined as a petroleum hydrocarbon fraction having a boiling point of 15°C to 200°C. It consists of a complex mixture of straight and branched chain paraffins (single and multi-branched), cyclic paraffins and aromatics having a carbon number ranging from 5 to about 11 carbon atoms. Light naphtha has a boiling point range of 15°C to 90°C and consists of C5 to C6 hydrocarbons, while heavy naphtha has a boiling point range of 90°C to 200°C and consists of C7 to about C11 hydrocarbons. Gas oils have a boiling point range of about 200°C to 350°C and consist of C10 to C22 hydrocarbons, essentially including linear and branched paraffins, cyclic paraffins and aromatics (including monoaromatics, naphtho-aromatics and polyaromatics). Heavier gas oils (such as atmospheric gas oil, vacuum gas oil, atmospheric residue and vacuum residue) have a boiling point range above 300°C and essentially C20+ hydrocarbons including linear and branched paraffins, cyclic paraffins and aromatics (including monoaromatics, naphtho-aromatics and polyaromatics) can be obtained from atmospheric or vacuum distillation units.

[0039] In particular, the cracking products obtained in the present process may include ethylene, propylene and benzene, and optionally hydrogen, toluene, xylene and 1,3-butadiene.

[0040] In embodiments, the outlet temperature of the shock wave reactor may be in the range of 820° C. to 1200° C., 830° C. to 1100° C., 840° C. to 950° C., or 850° C. to 940° C. The outlet temperature may affect the content of high-value chemicals in the pyrolysis products produced by the process.

[0041] In embodiments, the residence time of the feedstock through the section of the shock wave reactor where the temperature is between 650°C and 1200°C may be in the range of 0.005 to 0.5 seconds or 0.01 to 0.4 seconds.

[0042] In embodiments, steam cracking of the feedstock is carried out in the presence of steam at a ratio of 0.1 to 1.0 kg steam / kg hydrocarbon feedstock, 0.25 to 0.7 kg steam / kg hydrocarbon feedstock or 0.35 kg steam / kg feedstock mixture to obtain cracking products as defined above.

[0043] In embodiments, the shock wave reactor outlet pressure may be in the range of 500 to 1500 mbar, 700 to 1000 mbar, or may be about 850 mbar. The residence time and temperature of the feed in the shock wave reactor should be considered together. Lower operating pressures may result in easier formation of light olefins and reduced coke formation. The lowest possible pressure may be achieved by (i) maintaining the output pressure of the shock wave reactor as close as possible to the atmospheric pressure at the intake port of the cracked gas compressor; (ii) reducing the pressure of the hydrocarbons by diluting with steam (which has a substantial effect on slowing down coke formation). The steam / feedstock ratio may be maintained at a level sufficient to limit coke formation.

[0044] The effluent from the reactor may contain unreacted feedstock, desired olefins (primarily ethylene and propylene), hydrogen, methane, C 4 mixture (mainly isobutylene and butadiene), pyrolysis gasoline (C 6 To C 8 The pyrolysis gas is quenched rapidly to 338°C-510°C to stop the pyrolysis reaction, minimize the continuous reaction and recover the sensible heat in the gas by generating high pressure steam in a parallel transport line heat exchanger (TLE). In plants based on gaseous feedstocks, the TLE quench gas stream can flow forward to a direct water quench tower, where the gas can be further cooled with recycled cold water. In plants based on liquid feedstocks, a pre-fractionator can be located before the water quench tower to condense and separate the fuel oil fraction from the pyrolysis gas. In both types of plants, the main part of the heavy gasoline and dilution steam in the pyrolysis gas can be condensed in a water quench tower at 35°C-40°C. The water quenched gas can then be compressed to about 25-35 bar in 4 or 5 stages. Between the compression stages, condensed water and light gasoline can be removed, and the cracked gas can be washed with a caustic solution or with a regenerated amine solution followed by a caustic solution to remove acid gases (CO 2 , H 2 S and SO 2). The compressed cracking gas can be dried with a desiccant and cooled to a low temperature with propylene and ethylene refrigerants for subsequent product fractionation: pre-demethanization, pre-depropanization or pre-deethanization.

[0045] In embodiments, the hydrocarbon feedstock and dilution steam can be preheated in several stages before entering the shock wave reactor. First, the majority of the sensible heat and ultimately latent heat of the reactor effluent can be recovered by using a heat exchanger while preheating the hydrocarbon feedstock and dilution steam or boiling the feed water used thereby.

[0046] Additional preheating can be accomplished by electrical heating, either resistance heating, induction heating, microwave heating, or radiation heating.

[0047] Several physical concepts for heating fluids by using electricity are known in the art (see Fundamentals of Electroheat Electrical Technologies for Process Heating, Springer International Publishing Switzerland 2017 and Industrial Process Heating: Current and Emerging Applications of Electrotechnologies, Electric Power Research Institute 2010).

[0048] Resistance heating, also known as Joule heating or Ohm heating, is the process of generating heat by passing an electric current through a resistor. The coefficient of performance of resistance heating is 1.0, which means that one joule of heat is generated for each joule of electrical energy provided. The heated resistor transfers heat to the hydrocarbon feedstock and dilution steam. In embodiments of the present application, this can be accomplished in two ways. According to a first embodiment, the pipe through which the hydrocarbon feedstock, dilution steam, or a combination thereof flows is a heated resistor. According to a second embodiment, a resistor in any shape (wire, spiral, rod, etc.) is placed in a tubular or conduit envelope through which the hydrocarbon feedstock, dilution steam, or a combination thereof flows.

[0049] Induction heating is a non-contact method for heating conductive materials in an alternating magnetic field. An electromagnetic field is generated by applying an electric current at a given frequency to an inductor coil near a conductive workpiece. When the magnetic field crosses a workpiece made of any conductive material, it generates circulating currents (called eddy currents), which generate heat. The heated conductor transfers heat to the hydrocarbon feedstock and dilution steam. In an embodiment of the present application, this can be accomplished in two ways. According to a first embodiment, the pipe through which the hydrocarbon feedstock, dilution steam, or a combination thereof flows is a conductor heated by an electromagnetic field. According to a second embodiment, a conductive filler material in any shape (balls, extrudates, irregular particles, etc.) is placed in a tubular or conduit envelope through which the hydrocarbon feedstock, dilution steam, or a mixture thereof flows.

[0050] Microwave heating uses a specific part of the electromagnetic spectrum to internally heat low-conductivity materials. Dielectric heating is achieved by applying an electromagnetic field. The material to be heated is placed between two electrodes connected to a high-frequency generator. The electromagnetic field excites the molecular composition of the material, thereby generating heat within the material: the microwaveable material must have an asymmetric molecular structure with electric dipoles. The electric dipoles try to align with the orientation of the electric field, resulting in the movement of the molecules, thereby generating heat. The heated material transfers heat to the hydrocarbon feedstock and dilution steam. In embodiments of the present application, this can be accomplished in two ways. According to a first embodiment, the pipe through which the hydrocarbon feedstock, dilution steam, or a combination thereof flows is made of a microwaveable material. According to a second embodiment, a microwaveable filler material in any shape (spheres, extrudates, irregular particles, etc.) is placed in a tubular or conduit envelope, through which the hydrocarbon feedstock, dilution steam, or a combination thereof flows between the filler materials.

[0051] Electric radiation heating uses a heating element that reaches a high temperature, which is sometimes surrounded by an envelope and equipped with a reflector to direct energy output from the body of the heater toward the receiving material. The element emits infrared radiation that travels through space until it hits an absorbing surface (such as a tube containing a feedstock, dilution steam, or a mixture thereof), where it is partially converted into heat and partially reflected. In an embodiment of the present application, this can be accomplished by using a pipeline through which a hydrocarbon feedstock, dilution steam, or a combination thereof, heated by incident infrared radiation flows.

[0052] Renewable energy is energy that comes from natural sources or processes that are continuously replenished on human timescales, such as sunlight, wind, rain, tides, waves, hydropower and geothermal heat.

[0053] Low-carbon electricity refers to energy that comes from processes or technologies that produce electricity with significantly lower carbon dioxide emissions than conventional fossil fuel electricity generation. It includes low-carbon electricity generation sources such as wind, solar, hydroelectric, and nuclear power. The term largely excludes conventional fossil fuel sources.

[0054] The process of the present application is particularly advantageous in that the electrical heat source can use electricity derived from renewable or low-carbon energy sources. In this case, the process results in less CO2 than conventional steam cracking processes. 2 Emissions. One possible definition of renewable or low-carbon electricity is the CO emissions from producing the electricity. 2 The amount of CO emitted during electricity production 2 Some conventional values ​​of the quantities can be found in documents such as: Koffi, Brigitte; Cerutti, Alessandro; Duerr, Marlene; Iancu, Andreea; Kona, Albana; Janssens-Maenhout, Greet (2017): CoM Default Emission Factors for the Member States of the European Union - 2017 Edition, European Commission, Joint Research Centre (JRC) [dataset]. Such documents can be downloaded at the following URL: http: / / data.europa.eu / 89h / jrc-com-ef-comw-ef-2017.

[0055] As a proposed definition of renewable or low-carbon electricity, electricity with less than 0.2 tonnes of CO 2 Standard emission factor for electricity produced is renewable or low-carbon electricity, preferably less than 0.1 tonnes CO 2 / MWh or preferably less than 0.05 tonnes CO 2 / MWh. Standard emission factors are the emissions that occur due to the consumption of energy carriers using standard methods, i.e. using IPCC "standard" emission factors based on IPCC principles for stationary combustion of energy carriers. For the sake of clarity, other greenhouse gases such as methane and nitrogen oxides are not considered in these standard emission factors. Emissions related to the supply of energy carriers are also not considered in these emission factors, as they can vary greatly depending on the region and over time. For example, electricity generation from fossil resources emits the following amount of CO 2 : Highest efficiency combined cycle gas turbine (CCGT) power plant, 320-330kg CO 2 / MWh emissions; for modern open cycle gas turbine (OCGT) power plants, 500-520kg CO 2 / MWh; and for modern supercritical coal-fired power plants, 750-800kg CO2 / MWh, while nuclear power plants, geothermal, photovoltaic, hydroelectric and wind turbines emit 0kg CO 2 / MWh.

Claims

1. A method for cracking a hydrocarbon feedstock, comprising the following steps: feeding a hydrocarbon feedstock and dilution steam to a reactor; In the reactor, the hydrocarbon feedstock and the dilution steam are made to reach supersonic velocity at a temperature T1, Adding additional dilution steam at temperature T2, where T2 is higher than T1, subsequently applying a shock wave to the preheated hydrocarbon feed and dilution steam mixture to induce cracking of the hydrocarbon feed, thereby converting at least a portion of the mixture to produce olefins; wherein the hydrocarbon feedstock, the dilution steam and / or a mixture thereof are preheated before entering the reactor, and wherein the preheating is at least partially performed with the aid of one or more electrical heat sources, wherein the electrical heat source is powered by electricity produced with a standard emission factor of less than 0.2 tonnes of CO2 / MWh of electricity, Therein, the sensible heat or latent heat of the effluent leaving the reactor is at least partially extracted by means of one or more heat exchangers and is at least partially used to preheat the hydrocarbon feedstock, dilution steam or a mixture thereof.

2. The method according to claim 1, wherein: The weight ratio of the dilution steam to the hydrocarbon feed in the reactor is between 0.1 and 1.0 weight / weight, and The temperature of the hydrocarbon feedstock and dilution steam mixture before reaching supersonic speed is lower than 800°C.

3. The method according to claim 1, wherein: The hydrocarbon feedstock includes one or more hydrocarbons having at least two carbon atoms.

4. The method according to claim 2, wherein: The hydrocarbon feedstock includes one or more hydrocarbons having at least two carbon atoms.

5. The method according to claim 3, wherein: The one or more hydrocarbons having at least two carbon atoms are selected from the group consisting of ethane, liquefied petroleum gas, naphtha and gas oil.

6. The method according to claim 4, wherein: The one or more hydrocarbons having at least two carbon atoms are selected from the group consisting of ethane, liquefied petroleum gas, naphtha and gas oil.

7. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by resistive heating of at least one electrically conductive conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof.

8. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by resistive heating of an electrically conductive element within at least one conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof.

9. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by inductive heating of at least one electrically conductive conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof.

10. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by inductive heating of an electrically conductive fill material within at least one conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof.

11. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by heating at least one conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof, with an electrically powered external source of infrared radiation.

12. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by microwave heating of at least one low conductivity conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof.

13. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by microwave heating of a low conductivity fill material within at least one conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof.

14. The method according to any one of claims 1 to 6, wherein: The preheating is accomplished by heating a packing material within at least one conduit containing the hydrocarbon feedstock, dilution steam, or a mixture thereof using microwave interaction.

15. The method according to claim 14, wherein: The preheating is accomplished by heating a packing material within at least one conduit containing a hydrocarbon feedstock, dilution steam, or a mixture thereof, by microwave interaction with the silicon carbide.

16. The method according to any one of claims 1 to 6 and 15, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

17. The method according to claim 7, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

18. The method according to claim 8, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

19. The method according to claim 9, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

20. The method according to claim 10, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

21. The method according to claim 11, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

22. The method according to claim 12, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

23. The method according to claim 13, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

24. The method according to claim 14, wherein: said preheating of said hydrocarbon feedstock and said dilution steam is carried out separately in at least two conduits before mixing the two streams; or wherein the hydrocarbon feedstock and the dilution steam are mixed and then the mixture is simultaneously preheated; or Therein, the preheating of the hydrocarbon feedstock and the dilution steam is performed separately in at least two conduits to a temperature below 500° C., followed by mixing the two streams and simultaneously further preheating the mixture.

25. The method according to any one of claims 1-6, 15 and 17-24, wherein The supersonic speed is imparted by means of an electrically driven impeller.

26. The method of claim 16, wherein: The supersonic speed is imparted by means of an electrically driven impeller.

27. The method according to any one of claims 1-6, 15, 17-24 and 26, comprising recovering a methane stream comprising methane produced during cracking of the hydrocarbon feedstock; feeding the methane stream and dilution steam to a reactor; subjecting the methane stream and dilution steam to supersonic velocities in the reactor and subsequently applying shock waves to induce pyrolysis of the methane, thereby converting at least a portion of the methane to produce hydrogen, acetylene, and olefins; mixing the product of the reactor effluent with the product of the reactor effluent from cracking of the hydrocarbon feedstock, wherein the methane stream, the dilution steam and / or a mixture thereof are preheated before entering the reactor, and wherein the preheating is at least partially performed with the aid of one or more electrical heat sources.

28. The method according to claim 25, comprising recovering a methane stream comprising methane produced during cracking of the hydrocarbon feedstock; feeding the methane stream and dilution steam to a reactor; subjecting the methane stream and dilution steam to supersonic velocities in the reactor and subsequently applying shock waves to induce pyrolysis of the methane, thereby converting at least a portion of the methane to produce hydrogen, acetylene, and olefins; mixing the product of the reactor effluent with the product of the reactor effluent from cracking of the hydrocarbon feedstock, wherein the methane stream, the dilution steam and / or a mixture thereof are preheated before entering the reactor, and wherein the preheating is at least partially performed with the aid of one or more electrical heat sources.