Solid carbon-molten media separation in hydrocarbon pyrolysis reactor systems

Abstract

Methods for thermal cracking of a hydrocarbon to produce hydrogen gas are provided. The method includes the steps of: a. pumping a molten medium to flow through a reactor; b. mixing the hydrocarbon into the molten medium such that the mixed hydrocarbon and molten medium are carried through the reactor; c. at least while the mixed hydrocarbon and molten medium are being carried through the reactor, maintaining a temperature of the molten medium within at least a portion of the reactor at an operating temperature sufficient to thermally crack the hydrocarbon such that the hydrocarbon in the mixed molten medium and hydrocarbon is thermally cracked to yield carbon and a product gas; and d. injecting gas into the reactor to enhance the separation of the carbon from an interface of the molten medium to a collector of the reactor. Reactors for carrying out the methods are also provided.

Description

SOLID CARBON-MOLTEN MEDIA SEPARATION IN HYDROCARBON PYROLYSIS REACTOR SYSTEMSFIELD

[0001] This invention relates to separating solid carbon from molten media in hydrocarbon pyrolysis reactor systems.BACKGROUND

[0002] Hydrocarbon pyrolysis reactor systems that use molten media, such as molten metals and molten salts, crack hydrocarbons into smaller, industrially useful molecules such as hydrogen, olefins and the like. These systems are integral to the chemical and petrochemical industries, where the thermal decomposition of hydrocarbons is a fundamental process for producing a wide range of process chemicals and fuels.

[0003] Molten media serve dual roles in these reactors: as heat transfer agents and, in some cases, as catalysts that facilitate the pyrolysis reactions. The use of molten salts and metals facilitates uniform heat distribution, efficient heat transfer, and attainment of the high temperatures needed for pyrolysis.

[0004] The advantages of using molten media in hydrocarbon pyrolysis include improved heat management, higher thermal efficiencies, and enhanced product selectivity.

[0005] However, these systems also present specific operational challenges. Solid carbon, a product of the pyrolysis process in these reactors, floats on the interface of the molten media due to its lower density. The separation of solid carbon from the molten media is complex, especially in high-temperature environments (900- 1100°C), where issues include combustible gases (hydrogen, methane, etc.) and corrosion posed by many metals when exposed to molten media.

[0006] Efficiently separating solid carbon while minimizing the retention of molten media thereon is crucial for several reasons: the post-processing required to cleansolid carbon of molten media is costly and potentially harmful to the environment, particularly when molten salts are used and result in salty wastewater.

[0007] Furthermore, the economic impact of losing molten media, which may contain expensive catalysts and metals such as nickel, platinum, and tin, adds to the importance of optimizing the separation process.

[0008] Another challenge of these systems is the high temperatures of product gases and solid carbon outputted by the reactor, and the resultant requirement for specialized (i.e. , heat-resistant) downstream equipment and processes.

[0009] Improved systems that address at least some of these challenges are desirable.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings illustrate non-limiting example embodiments of the invention.

[0011] Figure 1 is a schematic view of a hydrocarbon pyrolysis reactor system with a conical collector according to an embodiment.

[0012] Figure 2 is a schematic view of a hydrocarbon pyrolysis reactor system with a conical collector with gas injectors in a molten media interface sweeping configuration according to an embodiment.

[0013] Figure 3 is a schematic view of a hydrocarbon pyrolysis reactor system with a conical collector with gas injectors in molten media interface suction configuration according to an embodiment.

[0014] Figure 4 is a schematic view of a hydrocarbon pyrolysis reactor system with a conical collector with gas injectors beneath the molten media interface according to an embodiment.DETAILED DESCRIPTION

[0015] Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well-known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive sense.

[0016] Figure 1 shows a hydrocarbon pyrolysis reactor system 100 that employs a thermal cracking process to convert hydrocarbon feedstock (e.g., methane, natural gas) into product gas (e.g. hydrogen, olefins) and solid carbon. System 100 has a reactor 104 with an inlet 102 where hydrocarbons HC are introduced into a body 107 of reactor 104 containing a molten medium MM maintained at a high temperature suitable for thermal cracking. This molten medium can include catalysts to enhance the thermal cracking process, allowing for lower temperatures, quicker, and more complete reactions.

[0017] The molten medium may include liquid metals, molten salts, or their combinations, chosen based on factors like cost, stability under operating conditions, and physical properties (e.g., melting point, boiling point, density, viscosity, vapor pressure, heat capacity, and thermal conductivity). Solid particles, potentially acting as catalysts (e.g., nickel, platinum), may also be added to the molten medium to increase the reaction rate and facilitate the removal of solid carbon build-up.

[0018] Heat is added to reactor 104 at different points to maintain the molten medium in a liquid state and at the desired temperature for thermal cracking. In some embodiments, high turbulence may help to mix the feed and the molten medium effectively and reduce the deposition of carbon on the reactor’s interior surfaces, as described for example in PCT / CA2021 / 05068.

[0019] Reactor 104 includes a bubble generator 106 to mix the hydrocarbon feedstock with the molten medium, creating bubbles B of gaseous feedstockwithin the molten medium. As the hydrocarbon feedstock gas is fed into body 107 of reactor 104 from the bottom it is heated by the molten medium and rises due to buoyancy and the motion of the molten medium. Heating causes the gas to expand, reducing its density, especially as hydrocarbons convert into gases such as hydrogen which are lighter than the original hydrocarbons at the same temperature. This conversion results in a higher volume and flow rate of gas leaving reactor 104 compared to what entered it.

[0020] The density of solid carbon is less than the density of the molten medium, allowing the solid carbon to float to an interface 108 of the molten medium with headspace 116 of reactor 104. For example, the density of solid carbon is about 200-400 kg / m3whereas the density of the molten media is about 2000-10,000 kg / m3. In some embodiments, the molten medium comprises a denser material (e.g., a liquid metal) and a less dense material (e.g., a molten salt). In such embodiments, an intermediate layer of the less dense material may form above the denser material. In such embodiments, solid carbon may float to interface 108 through the intermediate layer.

[0021] In some embodiments, system 100 may be equipped with a drain mechanism 110 such as a weir to manage the fluid level in reactor 104 and ensure efficient operation, a solid carbon trap 112 to prevent solid carbon from entering drain mechanism 110, and a molten medium recirculation loop 114 (via a make-up / recirculation tank and recirculation pump, not shown), as described for example in PCT / CA2022 / 051693. This setup maintains a constant molten media interface 108, facilitating efficient solid carbon removal as described further herein.

[0022] Product gas PG and solid carbon SC in headspace 116 collect in collector 118 of reactor 104 above molten media interface 108. The product gas and solid carbon are then outputted from system 100 at outlet 120. Also collecting in headspace 116 and exiting system 100 out of outlet 120 are any remaining hydrocarbons and other impurities (e.g., nitrogen, carbon dioxide, helium) present in the initial hydrocarbon feedstock.

[0023] One aspect of the present invention aims to enhance gas momentum at outlet 120 by optimizing the shape of the collector 118, as depicted in Figure 1 with a conical-shaped example. As gases rise from the molten media, conical collector 118 amplifies their velocity. The increased momentum directly influences the solid carbon particles floating on interface 108, propelling them away from interface 108 without direct mechanical interaction. The shape of collector 118 ensures that solid carbon particles, especially those minimally coated with molten media, are carried towards outlet 120. Heavier particles, laden with more molten media, remain at interface 108 until they detach from the media.

[0024] Depending on the embodiment, collector 118 may vary in shape, such as conical, semi-spherical, pyramidal, tetrahedral, and polyhedral. Each of these shapes narrows or tapers towards the top (or more generally, a downstream end of the collector), resulting in a smaller cross-sectional area at the top compared to the wider base at the bottom (or more generally, an upstream end of the collector), allowing channeling and acceleration of gases and particles upward, utilizing the principle that a narrower space speeds up flow and thus enhances momentum.

[0025] In some embodiments, combinations of one or more of these shapes are also viable, particularly in larger reactors, where a single collector might consist of several sub-collectors (e.g., four conical sections). Such embodiments: facilitate the creation of uniform gas momentum across the entire interface 108, ensuring consistent collection of solid carbon particles; and enhance the collector's structural integrity in high-temperature conditions, an important factor for large- diameter reactors.

[0026] The embodiments in Figures 2 to 4 incorporate features previously described in relation to the embodiment of Figure 1 , where like features are indicated by corresponding reference numerals. In addition, Figures 2 to 4 illustrate another aspect of the present invention, namely injecting gas in specific ways into the reactor to further enhance the separation of solid carbon from themolten media interface. This is particularly advantageous if the gaseous species from the pyrolysis reaction lack sufficient momentum to remove solid carbon from the interface.

[0027] In some embodiments the injected gas is cooler than the product gas, lowering the temperature of the mixture of product gas and solid carbon exiting the system. This cooling effect can reduce downstream processing costs, as it allows the use of more common and less expensive materials for downstream equipment. In some embodiments the injected gas reduces the temperature of the product gas and solid carbon (including any remaining hydrocarbons and other impurities) from a reaction temperature (e.g. from 900°C to 1100°C) to less than 850°C (for exotic alloys such as Inconel™ alloys, Hastelloy™ alloys, titanium, molybdenum, superalloys and the like), and to less than 560°C (for carbon steel). This downstream equipment can then operate at cooler temperatures, enhancing its durability and reliability.

[0028] The types of gases injected can vary, including:• Inert gases such as nitrogen or argon, which do not react with the product gas;• Tail gas from a product gas purification process, like that from a pressureswing adsorption (PSA) unit used in hydrogen separation; this tail gas often contains high levels of hydrogen due to separation inefficiencies, allowing for further hydrogen recovery instead of burning or venting it; and• Hydrocarbon gases, when the goal is to blend the produced hydrogen with hydrocarbons for decarbonization efforts, such as mixing hydrogen with natural gas in pipelines.

[0029] Figure 2 shows a hydrocarbon pyrolysis reactor system 200 with gas injectors 222 according to an embodiment. One or more gas injectors 222 are positioned within collector 218 and aimed at molten media interface 208. In this embodiment, gas injectors 222 propel gas towards molten media interface 208, boosting the momentum to dislodge solid carbon particles from molten media interface 208.

[0030] In some embodiments, gas injectors 222 are arranged in a manner to “sweep” solid carbon away from molten media interface 208 and towards outlet 220. In the embodiment illustrated in Figure 2, gas injectors 222 are angled (i.e. neither horizontal nor vertical) relative to a plane of molten media interface 208 to achieve the sweeping effect.

[0031] In some embodiments gas injectors are configured to sweep solid carbon from the molten media interface toward an area of the molten media interface where upward gas momentum in the collector toward the outlet of the reactor is greatest. In the embodiment illustrated in Figure 2, gas injectors 222 are configured to sweep solid carbon from the periphery of molten media interface 208 radially inward toward a center of molten media interface 208 where upward gas momentum in collector 218 toward 220 is greatest. In embodiments where the system has a plurality of collectors there may be a plurality of areas where upward gas momentum is equally the greatest. In such embodiments, the gas injectors may for example be configured to sweep solid carbon from the molten media interface toward the plurality of such areas.

[0032] In some embodiments, gas injectors 222 may comprise one or more of fan spray nozzles, gas atomizing nozzles, gas eductors, and the like. Gas eductors may enhance gas mixing in headspace 216 by the venture effect. In some embodiments, the shape of the gas stream released from gas injectors 222 is a full cone, hollow cone, flat, spiral, and the like. In some embodiments gas injectors 222 are positioned at least 5 inches above molten media interface 208 to prevent contact with any splashes of molten media.

[0033] The gas streams released from gas injectors 222 cover the entire (or most of) molten media interface 208. In some embodiments, gas injectors 222 may be arranged linearly (i.e., horizontal, vertical, and / or transverse), radially, semi- radially, and the like. The pressure of the released gas stream is high enough to provide the desired gas stream shape (e.g. full cone, hollow cone, flat, spiral, etc.), but not so high as to affect the operating pressure of system 200 (e.g. by activating pressure relief / safety valves). Also, the pressure (or velocity) of thereleased gas stream should not be so high as to cause the molten media to splash at molten media interface 208. The pressure (or velocity) should be sufficient to dislodge and remove the solid carbon, which has a significantly lower apparent density (due to its porous structure) than the molten media, from molten media interface 208.

[0034] In some embodiments, the gas stream from gas injectors 222 is a turbulent flow. In some embodiments, the gas stream flow rate is high enough to reduce the product gas and solid carbon temperature (including any remaining hydrocarbons and other impurities) exiting outlet 220 to less than the design temperature of the downstream equipment, for example to below 850°C or below 560°C.

[0035] Figure 3 shows a hydrocarbon pyrolysis reactor system 300 with gas injectors 322 according to an embodiment. Gas injectors 322 direct gas toward a narrowing of collector 318 in the direction of outlet 320, that is, in the downstream direction. This design leverages the venturi effect to create a vacuum-like condition, accelerating the product gas and solid carbon toward and out outlet 320 and inducing a significant pressure reduction within collector 318. In some embodiments, the pressure reduction is high enough to dislodge and remove solid carbon from molten media interface 308 but low enough to prevent suction and removal of molten media. In some embodiments the foregoing requirements are prioritized over the (reduction of) outlet temperature of the gas-solid carbon mixture. The narrowing of the passage toward outlet 320 increases the velocity of the gas flow, leading to a decrease in pressure in these regions according to the principles of fluid dynamics. This decrease in pressure effectively generates a suction force, enhancing the extraction of solid carbon particles from the molten media interface 308 by drawing them towards and out of system 300 through outlet 320.

[0036] Figure 4 shows a hydrocarbon pyrolysis reactor system 400 with gas injectors 422 according to an embodiment. Gas injectors 422 are positioned below molten media interface 408 in body 407 of reactor 404. Gas injectors 422 direct gas parallel to interface 408 and / or directly towards it in an angled manner. Theinjected gas enhances the gas momentum inside reactor 404, facilitating the detachment of solid carbon particles from interface 408.

[0037] The pressure of the released gas stream is high enough to dislodge and remove solid carbon particles from interface 408, but low enough to prevent removal of molten media. Gas injectors 422 are installed below and adjacent interface 408 to minimize their impacts on the effective reaction zone of reactants in body 407 of reactor 404, and also to minimize temperature increases of the gas stream by the molten media (as one of the functions of the gas streams is to cool down the product gases and solid carbon, as described above).

[0038] Similar to gas injectors 222, gas injectors 422 may comprise one or more of fan spray nozzles, gas atomizing nozzles, gas eductors, and the like. In some embodiments, the shape of the gas stream released from gas injectors 422 is a full cone, hollow cone, flat, spiral, and the like. The gas streams released from gas injectors 422 cover the entire (or most of) molten media interface 408, to increase the gas momentum uniformly across molten media interface 408. In some embodiments, gas injectors 422 may be arranged linearly (i.e. , horizontal, vertical, and / or transverse), radially, semi-radially, and the like. In some embodiments, the gas injectors 422 can additionally or alternatively be positioned to minimize solid carbon accumulation near the walls of body 407 by targeting those areas and directing the solid carbon particles toward the center of body 407 to collect them more effectively.

[0039] In some embodiments, one or more gas injectors 422 may be configured to serve dual purposes: the first as described above; and second as the inert gas injection component of pyrometers (infrared thermometers) or any other applicable instruments for measuring the temperature of the molten media.

[0040] The technology described herein may, for example, be implemented at or near natural gas facilities (e.g., pipelines, liquefied natural gas facilities) or at or near the point of use of produced hydrogen, or at any geographic location with access to natural gas or other suitable hydrocarbons as a feedstock.

[0041] The present disclosure explains various systems and corresponding methods according to the invention. Such methods may be applied using systems and apparatus that differ from the example systems and apparatus in the context of the systems depicted in the drawings. Many variations are possible, for example:• Gas injectors can include, but are not limited to, gas nozzles, gas sprayers, gas jets, gas ports, gas vents and the like.• Gas injectors can be operated continually, periodically, or intermittently.• Gas injectors can be configured to incorporate a combination of two or more of the designs described herein.• Gas injectors can be mounted in a collector of any shape, including those described herein.• Gas injectors can be mounted in a reactor of any type, including those described herein.• Gas injectors can be incorporated into any suitable hydrocarbon pyrolysis reactor system that uses molten media.• The collectors described herein can be incorporated into any suitable hydrocarbon pyrolysis reactor system.REFERENCES

[0042] The entire disclosures of all applications, patents, and publications, cited above and below, are hereby incorporated by reference. However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that prior art forms part of the common general knowledge in Canada or any other country.INTERPRETATION OF TERMS

[0043] Where a component ( e.g., a reactor, a collector, a gas injector, etc.) is referred to above, unless otherwise indicated, reference to that component (including a reference to a “means”) should be interpreted as including asequivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments of the invention.

[0044] Specific examples of systems, methods and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to systems other than the example systems described above. Many alterations, modifications, additions, omissions, and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled addressee, including variations obtained by: replacing features, elements and / or acts with equivalent features, elements and / or acts; mixing and matching of features, elements and / or acts from different embodiments; combining features, elements and / or acts from embodiments as described herein with features, elements and / or acts of other technology; and / or omitting combining features, elements and / or acts from described embodiments.

[0045] Various features are described herein as being present in “some embodiments”. Such features are not mandatory and may not be present in all embodiments. Embodiments of the invention may include zero, any one or any combination of two or more of such features. All possible combinations of such features are contemplated by this disclosure even where such features are shown in different drawings and / or described in different sections or paragraphs. This is limited only to the extent that certain ones of such features are incompatible with other ones of such features in the sense that it would be impossible for a person of ordinary skill in the art to construct a practical embodiment that combines such incompatible features. Consequently, the description that “some embodiments” possess feature A and “some embodiments” possess feature B should be interpreted as an express indication that the inventors also contemplate embodiments which combine features A and B (unless the description states otherwise or features A and B are fundamentally incompatible).

[0046] It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, omissions, and sub-combinations as may reasonably be inferred. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

WHAT IS CLAIMED IS:1 . A method for thermal cracking of a hydrocarbon to produce hydrogen gas, the method comprising: a. pumping a molten medium to flow through a reactor; b. mixing the hydrocarbon into the molten medium such that the mixed hydrocarbon and molten medium are carried through the reactor; c. at least while the mixed hydrocarbon and molten medium are being carried through the reactor, maintaining a temperature of the molten medium within at least a portion of the reactor at an operating temperature sufficient to thermally crack the hydrocarbon such that the hydrocarbon in the mixed molten medium and hydrocarbon is thermally cracked to yield carbon and a product gas; and d. injecting gas into the reactor to enhance the separation of the carbon from an interface of the molten medium to a collector of the reactor.

2. A method according to claim 1 wherein step d. comprises sweeping the carbon from the interface of the molten medium by providing one or more gas injectors for directing the injected gas toward the molten media interface from above the molten media interface to dislodge and remove carbon from the molten media interface.

3. A method according to claim 2 wherein the one or more gas injectors direct the injected gas toward the molten media interface at an angle from a plane of the molten media interface.

4. A method according to claim 2 or 3 wherein the one or more gas injectors sweep solid carbon from the molten media interface toward an area of the molten media interface where upward gas momentum in the collector toward an outlet of the reactor is greatest.

5. A method according to claim 4 wherein the one or more gas injectors sweep solid carbon from a periphery of the molten media interface radially inward towarda middle of the molten media interface.

6. A method according to claim 1 wherein step d. comprises providing one or more gas injectors for directing the injected gas toward a narrowing of a collector of the reactor and an outlet of the reactor to create a vacuum pressure in the collector to dislodge and remove carbon from the molten media interface.

7. A method according to claim 1 wherein step d. comprises providing one or more gas injectors for directing the injected gas toward the molten media interface from below and adjacent the molten media interface to dislodge and remove carbon from the molten media interface.

8. A method according to claim 1 wherein step d. comprises providing one or more gas injectors for directing the injected gas parallel to a plane of the molten media interface below and adjacent the molten media interface to dislodge and remove carbon from the molten media interface.

9. A method according to claim 7 or 8 wherein step d. further comprises providing one or more gas injectors for directing the injected gas toward walls of the reactor to minimize carbon accumulation near the walls and direct the solid carbon toward a center of the reactor.

10. A method according to claim 7 or 8 wherein step d. wherein at least one of the one or more gas injectors comprises a gas injection component of a pyrometer (infrared thermometer) or any other applicable temperature measurement instruments.

11. A method according to any one of claims 1 to 10 wherein the injected gas comprises one or more of an inert gas, a tail gas from a product gas purification process, and hydrocarbon gas.

12. A method according to any one of claims 1 to 11 wherein prior to step d. the injected gas is provided at a temperature lower than the product gas.

13. A method according to claim 12 wherein the temperature is low enough to reduce the temperature of the product gas and solid carbon exiting an outlet of the reactor to less than 850°C.

14. A method according to claim 13 wherein the temperature is low enough to reduce the temperature of the product gas and solid carbon exiting an outlet of the reactor to less than 560°C.

15. A method according to any one of claims 1 to 14 wherein step d. is performed continually, periodically or intermittently.

16. A method according to any one of claims 1 to 15 wherein a collector of the reactor narrows towards a downstream end of the collector.

17. A hydrocarbon pyrolysis reactor comprising: an inlet for receiving hydrocarbon feedstock; a body for reacting the hydrocarbon feedstock with molten media; a collector for collecting product gas and solid carbon from the body; and wherein the collector comprises: one or more gas injectors for enhancing separation of the solid carbon from an interface of the molten media and a headspace of the reactor; and an outlet for outputting the product gas and solid carbon from the reactor.

18. A hydrocarbon pyrolysis reactor according to claim 17 wherein the one or more gas injectors arrayed in the collector are configured to direct injected gas toward the molten media interface to dislodge and remove carbon from the molten media interface.

19. A hydrocarbon pyrolysis reactor according to claim 18 wherein the one or more gas injectors are configured to direct injected gas toward the molten mediainterface at an angle to a plane of the molten media interface.

20. A hydrocarbon pyrolysis reactor according to claim 18 or 19 wherein the one or more gas injectors are configured to sweep solid carbon from the molten media interface toward an area of the molten media interface where upward gas momentum in the collector toward the outlet of the reactor is greatest.21 . A hydrocarbon pyrolysis reactor according to claim 20 wherein the one or more gas injectors are configured to sweep solid carbon from a periphery of the molten media interface radially inward toward a middle of the molten media interface.

22. A hydrocarbon pyrolysis reactor according to claim 17 wherein the one or more gas injectors are configured to direct injected gas toward a narrowing of the collector leading to the outlet of the reactor to create a vacuum pressure in the collector to dislodge and remove carbon from the molten media interface.

23. A hydrocarbon pyrolysis reactor according to claim 17 wherein the one or more gas injectors are arrayed in the body below and adjacent the molten media interface and configured to direct injected gas toward the molten media interface to dislodge and remove carbon from the molten media interface.

24. A hydrocarbon pyrolysis reactor according to claim 17 wherein the one or more gas injectors arrayed in the body below and adjacent the molten media interface and configured to direct injected gas parallel to a plane of the molten media interface below and adjacent the molten media interface to dislodge and remove carbon from the molten media interface.

25. A hydrocarbon pyrolysis reactor according to claim 23 or 24 further comprising one or more gas injectors configured to direct injected gas toward walls of the body to minimize carbon accumulation near the walls and direct the solid carbon toward a center of the body.

26. A hydrocarbon pyrolysis reactor according to claim 23 or 24 wherein at least one of the one or more gas injectors comprises a gas injection component of a pyrometer (infrared thermometer) or any other applicable instruments.

27. A hydrocarbon pyrolysis reactor according to any one of claims 17 to 26 wherein the one or more gas injectors are configured to inject gas comprising one or more of an inert gas, a tail gas from a product gas purification process, and hydrocarbon gas.

28. A hydrocarbon pyrolysis reactor according to any one of claims 17 to 27 wherein the one or more gas injectors are configured to inject gas at a temperature lower than product gas.

29. A hydrocarbon pyrolysis reactor according to claim 28 wherein the temperature is low enough to reduce the temperature of the product gas and solid carbon exiting an outlet of the reactor to less than 850°C.

30. A hydrocarbon pyrolysis reactor according to claim 29 wherein the temperature is low enough to reduce the temperature of the product gas and solid carbon exiting an outlet of the reactor to less than 560°C.31 . A hydrocarbon pyrolysis reactor according to any one of claims 17 to 30 wherein the one or more gas injectors are configured to inject gas continually, periodically or intermittently.

32. A hydrocarbon pyrolysis reactor according to any one of claims 17 to 31 wherein the collector narrows towards a downstream end of the collector.

33. Methods having any new and inventive steps, acts, combination of steps and / or acts or sub-combination of steps and / or acts as described herein.

34. Reactors having any new and inventive feature, combination of features, or sub-combination of features as described herein.

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