EP4642566A1 - A shock wave reactor for thermal cracking and heating - Google Patents

Abstract

According to an embodiment shock wave device (100, 200) is disclosed suitable for thermal heating a process fluid comprising an axially oriented inlet (101, 201 ) and outlet (102, 202), thereby defining along an axis an axially enclosed volume, the device having between the inlet (101, 201 ) and the outlet (102, 202) a stage comprising a first rotor (104, 206) comprising a first set of vanes distributed around the axis and configured to rotate in a first rotation direction; a second rotor (105, 207) comprising a second set of vanes distributed around the axis and configured to rotate in a second rotation direction opposite to the first rotation direction; a vaneless space; and whereby the stage is configured to force the process fluid to flow from the inlet (101, 201) to the outlet (102, 202) by rotating the first (104, 206) and the second rotor (105, 207).

Description

A SHOCK WAVE REACTOR FOR THERMAL CRACKING AND HEATING

Field of the Invention

[01] The present invention relates to the field of oil- and petrochemical refinement and in particular to a reactor for thermal cracking of hydrocarbon and/or heteroatomic- containing compounds.

Background

[02] Thermal catalytic cracking is a process whereby molecules are decomposed into simpler, much lighter molecules by the application of heat with or without the presence of catalysts. The rate of cracking and the end products depend on the temperature and the presence of catalysts, but also on pressure and reactant concentration.

[03] One extreme of thermal cracking in terms of the product range is denominated by the high-temperature process called steam cracking which produces valuable ethylene and other feedstocks for the petrochemical industry. It is the principal industrial method for producing lighter alkenes, or commonly olefins. In this process, temperatures of circa 750 °C to 900 °C or even higher are needed.

[04] Currently, these processes are carried out using fossil fuel combustion furnaces. Therefore, steam cracking is considered to be a substantial contributor to the world’s greenhouse gas emissions producing more than three hundred million CO2 per annum of which 75-90% can be directly attributed to fossil fuel combustion. With the expected increase in global population, and the rising living standards of countries like Russia, Brazil, India, and China it is to be expected that the demand for olefins will keep on increasing in the near future. As a result, new plants should be built, and/or old plants should be retrofitted which would lead to an upsurge in production capacity but also in greenhouse gas emissions.

[05] To reduce greenhouse gas emissions the implementation of renewable energy sources and the electrification of large-scale production processes such as steam cracking in the chemical process industry is, therefore, a rational step towards reducing greenhouse gas emissions but is still in full development.

[06] A first implementation of electrical heating is inductive heating, which is defined as the heating induced by the presence of an alternating magnetic field that generates eddy currents that dissipate into heat within a ferromagnetic material. In document CN202226821 II a multi-stage combined electromagnetic heating pipe type continuous cracking refining reactor is disclosed. It discloses a reactor design that is coated with an insulating material above which an inductive coil is wrapped to provide the alternating magnetic field. In document WO2021180864A1 a hybrid tubular reactor configuration for steam cracking is disclosed comprising a traditional furnace design allowing the implementation of electrical heating, such as inductive, resistive, and direct heating, as well as a fossil fuel burner. As such the reactor design can cope with fluctuations in gas and electricity prices and availability. Along the same line, documents DE102018210409A1 and DE102015013071A1 compromise a hybrid design where a burner and inductive heating can be used simultaneously for heating a steam reformer reactor.

[07] A second implementation is resistive heating, also referred to as joule or ohmic heating, and is defined as the process where the energy of an electric current is converted to heat whilst flowing through a resistor. The resistor can be the reactor tube itself, such as disclosed in documents WO2015197181A, DE2362628A1 , WO2019228798A1 , and US20140238523A1 , or via well placed resistive sheets along the reactor tubes like in documents W02020002326A1 and WO2021130107. Similarly to the inductive heating approach, hybrid approaches have been disclosed in which resistive heating is combined with hot combustion gases to manage price and availability fluctuations, such as in documents DE102015004121A1 , LIS2016288074, and WO2021180864A1.

[08] Both resistive and inductive heating offer the advantage that the implementation in existing furnaces is relatively easy and cheap. This is because during a major overhaul all the furnace tubes of a traditional steam cracking furnace are typically replaced. Hence, offering the possibility to replace these conventional tubes with resistive or inductive supporting tubes, and in case side equipment, without the need to drastically change the furnace design. As a result, the current cracking units can be electrified. Nevertheless, disadvantages inherently related to the state-of-the-art furnace remain.

[09] First of all, inductive and resistive heating rely on the fact that heat transfer occurs from the outside to the inside of the tube. As a result, the tube surface is the hottest place in the reactor while the tube centre is the coldest due to endothermic reactions. As coking is a thermally activated process, it is to be expected that high coking rates will occur there where the temperature is the highest which is at the process gas/tube surface. Moreover, the presence of cokes indicates the occurrence of secondary reactions vastly reducing the olefin yield, which are the components of interest.

[10] Secondly, cokes do form an insulating layer affecting the conductive resistance against heat transfer from the tube surface to the process fluid. To overcome this growing resistance, and hence maintain the same cracking seventy, additional power must be supplied. For inductive and resistive heating this leads to higher electric consumption and thus operational expenses. Providing additional power to the tube, will in its turn lead to higher tube metal temperatures which are limited by the metallurgy of the tube itself. Hence, on a regular basis - whenever the tube temperature or pressure drop becomes too high - the production must be ceased to decoke the reactors. This requires the production to be halted for up to forty-eight hours, leading to considerable adverse effects on the process economics.

[11] Besides coking as an inherent problem, also the way heat is transferred from the furnace side to the process side does limit the obtainable yield and ethylene selectivity. Heat must be transferred from the hot furnace side through the tube wall towards the process side, each having its resistance against heat transfer. Hence, a recent trend is to use advanced 3D reactor geometries to enhance the heat transfer from the hot tube wall to the process fluid, leading to some minor advantages, nevertheless remaining a limiting factor.

[12] A third implementation is microwave heating, which exploits molecular interactions of a mixture to heat a fluid from the inside, hence circumventing the need for an intermediate hot material when used for fluids other than gasses. For a gas phase, however, solid susceptors are needed to absorb the radiation and turn it into heat. For example, SiC is an excellent susceptor for microwave heating, having both an elevated electrical permittivity and loss factor to radiation. Nevertheless, the presence of these susceptors leads to an intermediate hot surface from which the heat is transferred to the gaseous process fluid.

[13] Siauw et al. (Ng, Siauw et al. "Microwave-Assisted Conversion Of Ethane To Ethylene". Applied Petrochemical Research, vol 3, no. 1 -2, 2013, pp. 55-61 ) reported a pilot-scale microwave reactor for steam cracking. From the experimental results, it is concluded that this newly developed steam cracking reactor achieves product yields as a traditional furnace yet achieves a projected energy savings of 30% compared to conventional reactors.

[14] A fourth implementation is shockwave heating, for example through nozzle type reactors. Nozzle type reactors are a type of pyrolytic reactor that utilises hot carrier gases and the principle of a DeLaval nozzle to generate supersonic hot carrier gas flows. Via judiciously placed injection nozzles, the cracked feedstock is injected into this supersonic carrier gas and transported to the mixing zone where intense mixing between the hot carrier gas and the feedstock arises. A reaction zone is placed adjacent to the mixing zone. As a result, the velocity of the mixed stream transitions from supersonic to subsonic within the reaction zone. At this transition point, a shock wave occurs resulting in an instantaneous increase in static pressure and temperature. The increase of temperature within this mixed stream provides enough energy to satisfy the high energy needs of the occurring endothermic reactions. [15] The high-temperature carrier gas required in this type of reactor can be prepared via the ignition of a fuel and oxidiser. This ignition device can be - among others - a hot platina wire, a spark plug, or auto-ignited components/mixture. Once ignited the production of carrier gas is, in most cases, self-sustaining due to the high temperatures of the ignited mixture. According to document WO2015077335A2, the combustion of hydrogen is deemed to be the most suitable for olefin production as this results in the formation of water vapor which will dilute - and hence reduce the partial pressure of - the hydrocarbon feed and thus improve the light olefin yields. Different configurations are also disclosed such as in documents US4136015A, EP0158863A3, US5300216A, W02006073521 A2, US2009266741 A1 , WO2014031288A1 ,

WO2014031512A2 and WO2015077335A2.

[16] Another application of shockwave heating is turbomachine-like reactors that utilize high-speed rotation to transform mechanical energy into thermal energy. Such a reactor has an inlet and outlet with a vaneless spaced duct in which one or more stages are positioned. A stage in this context is defined as a single rotating blade and two stationary vane cascades, whereby the vanes are positioned side-by-side with the first cascade the stator, the second cascade the rotating blade, and the last cascade the diffuser.

[17] Such a shock wave reactor relies on the principle that the rotor accelerates the process fluid thereby providing the required kinetic energy reaching supersonic levels, which is then reduced in the subsequent diffuser cascade. The subsonic fluid enters a vaneless space where residence time, turbulence, and temperature are sufficiently large for chemical reactions to take place. After this vaneless space, another stage may be implemented thereby repeating the process. This repetitive combination of stage-vaneless spaces may continue until the desired conversion is reached, before discharging the fluid from the reactor outlet.

[18] During the transfer from the inlet to the outlet the feedstock will be sent through multiple sets of the stator, rotor, diffuser vanes, and vaneless spaces. Each time the fluid passes the set of vanes, the kinetic energy increases thereby reaching supersonic levels, and heat is generated upon the reduction of flow velocity, i.e. subsonic velocities in the vaneless space. Specifically, this movement generates stationary shockwaves. Across a strong shock wave, the flow decelerates from supersonic to subsonic speeds over a very small length of the order of a few micrometres, where velocity is traded for enthalpy, resulting in extremely fast heating times for shock- heated gases of the order of nanoseconds.

[19] In W02016001476A1 a rotary machine type reactor suitable for the pyrolysis of hydrocarbon-containing feedstock by means of shock waves is disclosed. In W02020074780A1 another rotary machine type reactor is disclosed to conduct chemical reactions in a process fluid comprising a mixing space configured to convert mechanical energy imparted to the process fluid by the rotor into internal energy of said process fluid and to establish conditions for at least one chemical reaction in the process fluid to occur. In WO2019221726A1 another chemical reactor for cracking hydrocarbon in a process fluid by generating shock waves is disclosed. As a final example, in W02020060919A1 a turbomachine type chemical reactor is disclosed for processing a process flow comprising an exhaust section arranged downstream of a stationary diffuser section, the exhaust section comprising a plurality of convergent exhaust flow passages configured to provide a back pressure such that a shock wave is generated in the stationary diffuser section.

[20] In EP3164207A1 a helical-path reactor is disclosed comprising a rotor with a shaft and a disk provided with blades forming an axial flow rotor blade cascade, a stationary directing ring shaped rim optionally provided with at least two stationary vane cascades adjoining the axial-flow rotor cascade, and a casing. In LIS2014243569 a rotary machine type reactor is disclosed suitable for the pyrolysis of hydrocarbon- containing feedstock.

[21] A disadvantage of the shock wave reactors known in the art is that they are quite vast since the temperature increase per stage is limited. To reach a temperature suitable for the steam cracking process a series of stages are therefore needed.

[22] It is therefore an object of the present invention to alleviate the above drawback and to provide an improved shock wave reactor for thermal cracking a process fluid. Summary of the Invention

[23] This object is achieved, in a first aspect, by a shock wave device according to claim 1 , the shock wave device suitable for thermal heating a process fluid comprising an axially oriented inlet and outlet defined by a set of annuli with their respective centres coinciding with an axis of the reactor thereby defining along the axis an axially enclosed volume, the device having between the inlet and the outlet a stage comprising:

- a first rotor comprising a first set of vanes distributed around the axis and along the annuli and configured to rotate in a first rotation direction around the axis;

- a second rotor comprising a second set of vanes distributed around the axis and along the annuli and configured to rotate in a second rotation direction opposite to the first rotation direction around the axis; whereby the stage is configured to force the process fluid to flow from the inlet to the outlet by rotating the first and the second rotor; and whereby the first set of vanes is configured to guide the process fluid from the inlet to the second set of vanes, and the second set of vanes configured to guide the process fluid to a vaneless space; and whereby the stage is further configured to accelerate the process fluid to a supersonic velocity at the second set of vanes such that when entering the vaneless space the velocity is reduced to a subsonic velocity thereby generating a stationary shock wave for heating the process fluid.

[24] The shock wave device may have a primarily cylindrical shape having an axis, whereby at the endings thereof at both sides an inlet, respectively, an outlet is situated. Further, along the axis, there is a hub and a shroud. Alternatively, the shock wave device may be conically frustum shaped, again having an inlet respectively an outlet at both endings and a hub and a shroud. The radius of a circle definable at the side of the inlet will then be smaller than the radius of a circle definable at the side of the outlet, or vice versa, whereby the shock wave reactor smoothly tapers between the inlet and the outlet, or in case vice versa. Furthermore, instead of smoothly tapering or contracting, this may also be done in a gradual or cascading manner. The rotational axis of the conically frustum shaped shock wave reactor is then the imaginary line connecting the midpoint of said circles. Differently formulated, both the hub and the shroud, i.e. inner and outer circle, respectively, can contract and/or expand in any configuration. This means that the hub can contract or expand, the shroud can contract or expand, and that both the hub and shroud can contract and expand. The shock wave reactor, either being cylindrical or conical frustum shaped, is therefore configured to let a process fluid flow from said inlet to the outlet via an axially configured enclosed volume.

[25] Around the axis a series of first and second concentric circles with their centres coinciding with the axis of the shock wave reactor and having a first respectively second radius can be defined, whereby the first radius is bigger than the second one. The region between said circles, being annuli along the axis of the cylinder, defines the enclosed volume.

[26] In case the shock wave reactor is cylindrical, the radii of the circles, and therefore the annuli as well, are constant along the axis. In case the shock wave reactor is conical frustum shaped, the radii increase along the axis towards the outlet or vice versa.

[27] The set of vanes may further be distributed along said annuli along the axis.

[28] Through the enclosed volume the process fluid flows, whereby the shock wave reactor is configured to thermally crack said process fluid being, for example, complex organic molecules or long-chain hydrocarbons into simpler molecules, but also being, among others, methane, ammonia, or even hydrogen sulphide for the production of hydrogen, as will be discussed further.

[29] To reach the temperature needed for such a process, the shock wave reactor comprises one or more stages configured to heat up the process fluid.

[30] A stage is arranged between the inlet and the outlet and comprises in the direction seen from the inlet to the outlet a first rotor, a second rotor, and a vaneless space. Optionally and according to an embodiment, a stator is positioned between the inlet and the first rotor.

[31] The first and the second rotors are of an impulse type. This is because the Euler turbomachine equation states that the more turning one can do with a rotor, the higher the total enthalpy will be. Hence, the rotors will provide mechanical energy to the process fluid.

[32] The stator when present comprises a set of vanes that are in a static manner arranged and distributed around the axis. In other words, this set of vanes is a stationary set of vanes. The term stator thus indicates that this element is a static part of the reactor.

[33] The stator is designed in such a way that the process fluid is accelerated and distributed to let it flow across the rotor. This makes sure that the flow incidence on the first rotor is within the optimal incidence range, which is of utmost importance for optimal operation of the shock wave reactor.

[34] The stage further comprises a first rotor comprising another set of vanes distributed around the axis. The term rotor indicates that this part of the reactor is configured to rotate around the axis of the shock wave reactor. Additionally, the stage comprises a second rotor having another set of vanes likewise distributed around the axis.

[35] After the second rotor seen in the direction between the inlet towards the outlet along the axis, there is a vaneless space. Within this vaneless space, the majority of the thermal cracking process takes place, whereas a part of the cracking reactions may also take place in the vaned section, as explained as follows.

[36] The stage is configured to force the process fluid to flow from the inlet to the outlet due to the shape and configuration of the different set of vanes in combination with a driving force that originates when the rotors are rotating. [37] The process fluid enters the stage via the inlet, to the first set of vanes, to the second set of vanes, to the vaneless space, and finally to the outlet. When the stator is present, the process fluid likewise enters the stage via the inlet, thereafter to the third set of vanes, to the first set of vanes, to the second set of vanes, to the vaneless space, and finally to the outlet.

[38] The vanes are further configured to increase the velocity of the flowing process fluid when the rotors are rotating. This is performed by two counterrotating rotors. This is, the first rotor turns in a certain direction, for example clockwise, such that the second rotor turns in the other direction, thus in this case counterclockwise. It should be clear that this may also be reversed as long as the rotors rotate in opposite directions. The second set of vanes may be further configured to reduce the process velocity when entering the vaneless space.

[39] The shape of the vanes can vary in each stage to accommodate the best possible conditions along the central axis of the shock wave reactor.

[40] Further, the rotors turn at a rotational speed such that the process fluid is accelerated to a supersonic velocity, thus above the speed of sound at least at the set of vanes of the second rotor. When then entering the vaneless space, the process fluid enters the volume thereof and gets reduced in speed from supersonic to subsonic, thus below the speed of sound.

[41] The choice of material strongly depends on the conditions in which the shock wave device will be used and thus the thermal and mechanical stress that will be exerted on the material. In addition, the shock wave device can be built with different materials. For example, one can choose to manufacture the rotors having high mechanical stress with a high nickel/cobalt content (e.g. INCONEL 718) and the vaneless space in a material with a lower nickel content (e.g. 35Cr/45Ni alloy) in order to achieve reduced catalytic coke deposition while still having adequate carburization and thermal stress resistance.

[42] When going from a supersonic to a subsonic velocity, stationary shock waves are generated at the interface of this transition within the process fluid. These generated shock waves on their behalf then generate heat or produce heat, meaning that the process fluid is heated up. When the heating is sufficiently high, the thermal cracking process can take place partly in the vaned section, and for the most part, thereof in the vaneless space.

[43] Within the vaneless space, the residence time of the process fluid should preferably be less than 100ms, even more preferably less than 50ms, and most preferably less than 25ms. The upper limit of this residence time being 100ms determined by the limits of conventional cracking reactors, whereas the lower limit being 25ms or less is determined by thermodynamic and kinetic properties in the system and therefore dependent on the feedstock and desired conversion rate.

[44] Instead of specifying the residence time in absolute terms, it may also be defined relative to the speed of sound of the process fluid, which is as known dependent on the gas composition and temperature. In this disclosed shock wave device the flow of the process fluid will be higher than its respective speed of sound for generating shock waves. According to an embodiment, the gas particles of the process fluid will flow with a Mach number of more than 1 .5 through the vanes at an oblique angle, or even up to a Mach number of 3. Note that it is the projection of this speed in the axial direction that is of importance to know the residence time of the process fluid within the device. Furthermore, when defined in absolute times expressed in seconds, the length of the device needs to be considered as well. Therefore, an important parameter for defining the residence time is the axial Mach number, which is the ratio of the axial velocity of the gas to the speed of sound of the gas. The residence time in the device is thus the device’s axial length over the axial Mach number times the speed of sound of the gas. The first and last parameters of this formula depend specifically on the size of the device and the choice of gas, respectively. The axial Mach number depends on the design and is preferably higher than 0.3 but less than 1 , and more preferably in the range between 0.4 and 0.8 depending on the radial position.

[45] An advantage with regard to reactors known in the art is that by using counterrotating rotors the achievable enthalpy increase per stage is at least doubled without the need of building a reactor twice as large resulting in a more compact design. Therefore, the disclosed shock wave reactor according to the invention is smaller and more flexible compared to those known in the art. Furthermore, since the two rotational velocities may vary, whereas reactors known in the art only have one varying rotational velocity, it is easier to cope with feedstock changes, but also along the axial direction of the reactor.

[46] Furthermore, the thermal heating step will be quicker compared to the shock wave device known in the art. The average time from the leading edge of the first rotor to the trailing edge of the second rotor will be in the order of magnitude of 0.2ms. According to an embodiment, from the leading edge of the first rotor to the trailing edge of the second rotor will be in the order of magnitude of 0.2ms to achieve a static temperature increase of 150 °C.

[47] According to an embodiment, the vaneless space may comprise one or more catalytic elements and/or catalytic voids and/or coatings. Thus a catalytic bed, whether fixed or not, may be present in the vaneless space. In a similar fashion, a catalytic coating on the vanes and the vaneless space may be present as well. This way cokes and/or fouling formation are suppressed and are further used to perform catalytic chemical reactions.

[48] According to an embodiment, the catalytic elements and/or catalytic voids are formed by or provided with a ceramic or metallic substrate or support carrier.

[49] The vaneless space will have a variable sized axial length to enclose the most desirable operating conditions for the chemical reactions to occur. For example, for steam cracking a swift initial temperature increase is desired and thus the initial vaneless spaces must be as short as possible. Furthermore, besides guiding the flow between stages, the vaneless space offers the time and space to partially convert potential pressure and kinetic velocity energy into internal energy through the increase of entropy.

[50] The vaneless space can entail different objects, for example, turbulator grids, 3D indents at the hub and shroud to further increase the entropy of the fluid. [51] The vaneless space can also be vaned. Consequently and according to an embodiment, the stage may further comprise a stationary diffuser positioned between the second rotor and the vaneless space comprising a fourth set of vanes distributed around the axis; and whereby the second set of vanes is further configured to guide the process fluid to the fourth set of vanes, and the fourth set of vanes configured to reduce the process fluids velocity when entering the vaneless space.

[52] When the diffuser and the stator are present, the average time needed for the thermal heating step, thus from the leading edge of the stator to the trailing edge of the diffuser will be in the order of magnitude of 1 ms.

[53] The diffuser is placed downstream of the second rotor thereby aiding in the velocity reduction through diffusion and shockwave generation in order to increase the static enthalpy as much as possible. The diffuser may, according to an embodiment, further be configured to generate turbulence of the process fluid within the vaneless space.

[54] According to an embodiment, the shock wave reactor further comprises a drivetrain configured to drive the first and second rotor. The drivetrain can comprise an electrical motor configured in such a way that the rotors can rotate in opposite rotational directions. The drivetrain may further be configured such that the rotors may rotate independently, for example, with two motors or engines, or with a single engine and an appropriately designed planetary gear system.

[55] According to an embodiment, the shock wave reactor may comprise a set of sequentially configurated stages along the axis.

[56] According to a second aspect, a method is disclosed for thermal cracking a process fluid by the use of a shock wave reactor according to the first aspect of the invention. Brief Description of the Figures

The invention will be further illustrated with reference to the figures, wherein:

[57] Fig. 1 illustrates an orthographic view of a cylindrical shaped shock wave reactor with a stage comprising an inlet, an outlet, a stator, and two counterrotating rotors;

[58] Fig. 2 illustrates an orthographic view of a conically frustum shaped shock wave reactor with a stage comprising an inlet, an outlet, a stator, and two counterrotating rotors;

[59] Fig. 3 illustrates a perspective view of a shock wave reactor having two stages and a vaneless space in between; and

[60] Fig. 4 illustrates an orthographic view of a shock wave reactor having multiple stages.

Detailed Description of Embodiments

[61] The present invention will be described with respect to certain embodiments and with reference to certain figures, but the invention is not limited thereto and is defined only by the claims. The figures described are only schematic and non-limiting. In the figures, the size of certain elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and relative dimensions do not necessarily correspond to actual practical embodiments of the invention.

[62] In addition, the terms first, second, third and the like are used in the specification and in the claims to distinguish between like elements and not necessarily to describe a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention may be used in sequences other than those described or illustrated herein.

[63] Furthermore, the terms top, bottom, over, below and the like in the specification and claims are used for illustrative purposes and not necessarily to describe relative positions. The terms so used are interchangeable under appropriate circumstances, and the embodiments of the invention described herein may be used in orientations other than those described or illustrated herein.

[64] Further, although referred to as "preferred embodiments", the various embodiments are to be construed as exemplary in which the invention may be practiced rather than as a limitation on the scope of the invention.

[65] The term "comprising", used in the claims, should not be construed as being limited to the means or steps set forth below; the term does not exclude other elements or steps. The term should be interpreted as specifying the presence of the named features, elements, steps, or components referred to, but does not exclude the presence or addition of one or more other features, elements, steps, or components, or groups thereof. The scope of the expression "a device comprising means A and B" should therefore not be limited to devices consisting only of the components A and B. The meaning is that with respect to the present invention only the components A and B of the device are listed, and the claim is further to be interpreted as including equivalents of these components.

[66] Fig. 1 illustrates an orthographic view 100 a cylindrical shaped shock wave reactor with a stage comprising an inlet 101 , an outlet 102, a stator 103, and two counterrotating rotors 104 and 105.

[67] The rotors 104 and 105 are driven by using a planetary gear system allowing them to counterrotate. A drive shaft is torqued by an engine, for example an electrical motor, whereby flanged sun gears are mounted on the drive shaft to rotate an assembly of planetary gears in a counterclockwise direction. The planetary gears, in turn, rotate a structural support inner casing counterclockwise. This mechanism causes the first rotor 104 attached to the drive shaft to rotate in a direction opposite to the second rotor 105 attached to the inner casing, or vice versa.

[68] The rotation respectively counterrotation of rotors 104 and 105 can be controlled by adjusting the gear ratios of the planetary gear systems. Additionally, the direction of rotation of the shaft used in the above illustration does not need to be clockwise but may also be adapted to rotate counterclockwise, which in turn will rotate the planetary gear system in a clockwise direction.

[69] The above illustration of how rotors 104 and 105 are mechanically driven is also applicable to the devices as illustrated by the other figures.

[70] With again reference to Fig. 1 , the process fluid will enter the shock wave device through the inlet 100. The inlet is defined as the annulus with inner circle with diameter 111 and outer circle with diameter 110. The outer circle 110 therefore represents the border of the shroud, and the inner circle 111 the border of the hub. In this illustration, a stator 103 is present and further a first rotor 104 and a second rotor 105 and an outlet 102. Through the rotation of the first rotor 104 and the rotation of the second rotor 105 in an opposite direction, the process fluid accelerates as already explained above.

[71] Device 100 of Fig. 1 has a cylindrical shape, while in Fig. 2 another device 200 is illustrated with a conical frustum shape. The inlet is defined between the shroud, represented by line 210, and the hub, represented by lines 203 and 204. In this configuration the hub diameter 203 near the inlet 201 is greater than the hub diameter 204 near the outlet 202. The throughflow area near the inlet 201 is thus smaller and so the hydraulic inlet diameter is smaller as well. Note that this can also be designed in an opposite manner. The device 200 further has a stator 205, a first rotor 206, and a second rotor 207 in a similar manner as in Fig. 1 .

[72] Fig. 3 illustrates a perspective view of a shock wave reactor 300 having two stages 301 and 302 and a vaneless space 303 in between those two stages 301 and 302. These stages 301 , 302 are similar to the stages as illustrated in Fig. 1 and Fig. 2. The shock wave reactor 300 further comprises turbulators for turning a laminar boundary layer into a turbulent boundary layer. The turbulators are located at both hub and shroud, but this can also only be present on the hub or shroud. The turbulators are illustrated by the concentric circles at the vaneless space 303. The device 300 further has an inlet 310 and an outlet 311 .

[73] In Fig. 4 an orthographic view of a shock wave reactor having multiple stages is illustrated. The reactor has an inlet 411 and an outlet 410, and a cylindrical shroud 413 and cylindrical hub 412. The first stage 403 comprises in fact multiple stages as already defined above. In particular it comprises three stages, whereby the first stage thereof comprises a stator 430, a rotor 431 , a contra-rotor 432 and a diffuser 433, and the subsequent stages having the same configuration. The other stages 402, 401 , and 400 all have a same configuration, namely a stator, a rotor, a contra-rotor, and a diffuser. Between stages 403 and 402, 402 and 401 , and 401 and 400 there are vaneless spaces 422, 421 , and respectively 420. Within these vaneless spaces there are catalytic beds.

Claims

1.- A shock wave device (100, 200) suitable for thermal heating a process fluid comprising an axially oriented inlet (101 , 201 ) and outlet (102, 202) defined by a set of annuli with their respective centres coinciding with an axis of the reactor thereby defining along the axis an axially enclosed volume, the device having between the inlet (101 , 201 ) and the outlet (102, 202) a stage comprising:

- a first rotor (104, 206) comprising a first set of vanes distributed around the axis and along the annuli and configured to rotate in a first rotation direction around the axis;

- a second rotor (105, 207) comprising a second set of vanes distributed around the axis and along the annuli and configured to rotate in a second rotation direction opposite to the first rotation direction around the axis; whereby the stage is configured to force the process fluid to flow from the inlet (101 , 201 ) to the outlet (102, 202) by rotating the first (104, 206) and the second rotor (105, 207); and whereby the first set of vanes is configured to guide the process fluid from the inlet (101 , 201 ) to the second set of vanes, and the second set of vanes configured to guide the process fluid to a vaneless space; and whereby the stage is further configured to accelerate the process fluid to a supersonic velocity at the second set of vanes such that when entering the vaneless space the velocity is reduced to a subsonic velocity thereby generating a stationary shock wave for heating the process fluid.

2.- The shock wave device (100, 200) according to claim 1 , the stage further comprising:

- a stator (103, 205) between the inlet (101 , 201 ) and the first rotor (104, 206) comprising a third set of vanes distributed around the axis; and wherein the third set of vanes is configured to guide the process fluid from the inlet (101 , 201 ) to the first set of vanes.

3.- The shock wave device (100, 200) according to any of the preceding claims, whereby the second set of vanes is further configured to reduce the process fluids velocity when entering the vaneless space.

4.- The shock wave device (100, 200) according to any of the claims 1 or 2, the stage further comprising:

- a stationary diffuser after the second rotor comprising a fourth set of vanes distributed around the axis; and whereby the second set of vanes is further configured to guide the process fluid to the fourth set of vanes, and the fourth set of vanes configured to reduce the process fluids velocity when entering the vaneless space.

5. - The shock wave device (100, 200) according to claim 4, wherein the diffuser is further configured to generate turbulence of the process fluid within the vaneless space.

6.- The shock wave device (100, 200) according to any of the preceding claims, wherein the set of vanes is further distributed along annuli along the axis.

7.- The shock wave device (100, 200) according to claim 6, wherein the radii of the concentric circles of the annuli are constant along the axis.

8.- The shock wave device (100, 200) according to any of the preceding claims, wherein the vaneless space comprises one or more catalytic elements and/or catalytic voids and/or coatings.

9.- The shock wave device (100, 200) according to claim 8, wherein the catalytic elements and/or catalytic voids are formed by or provided with a ceramic or metallic substrate or support carrier.

10.- The shock wave device (100, 200) according to any of the preceding claims further comprising a drivetrain configured to drive the first and second rotor.

11.- The shock wave device (100, 200) according to any of the preceding claims wherein the shock wave device comprises a set of sequentially configurated stages along the axis.

12.- The shock wave device (100, 200) according to any of the preceding claims, wherein the device is cylindrically shaped

13.- The shock wave device (100, 200) according to any of the claims 1 to 11 , wherein the device is conically frustum shaped.

14.- A method for thermal heating a process fluid by the use of a shock wave device (100, 200) according to any of the preceding claims.