WO2024254675A1

WO2024254675A1 - Valve assembly and feedstock reactor with a valve assembly

Info

Publication number: WO2024254675A1
Application number: PCT/CA2024/050621
Authority: WO
Inventors: Milo DEL BIGIO
Original assignee: Ekona Power Inc
Current assignee: Ekona Power Inc
Priority date: 2023-06-14
Filing date: 2024-05-07
Publication date: 2024-12-19
Anticipated expiration: 2025-12-14

Abstract

A valve assembly includes a rotary valve with a rotor and a stator, and defining a first axis of rotation. The valve assembly further includes gearing connected to the rotor and a drive mechanism connected to the gearing. Operation of the drive mechanism drives rotation of the gearing which generates a rotational force about the first axis of rotation for driving rotation of the rotor relative to the stator, and an axial force along the first axis of rotation for maintaining contact between the rotor and the stator during the rotation of the rotor relative to the stator.

Description

VALVE ASSEMBLY AND FEEDSTOCK REACTOR WITH A VALVE ASSEMBLY

Field

[0001] The present disclosure relates to thermal pyrolysis and in particular to a feedstock gas reactor with a valve assembly, and to the valve assembly itself.

Background

[0002] Thermal pyrolysis is a method by which a feedstock gas, such as a hydrocarbon, is decomposed without oxygen into its constituent elements (in the case of a hydrocarbon, carbon and hydrogen). The decomposition is triggered by sufficiently raising the temperature of the feedstock gas to a point at which the chemical bonds of the elements of the feedstock gas break down.

[0003] Such pyrolysis may be achieved, for example, by bringing the feedstock gas into thermal contact with a hot fluid. For instance, combustion product gases, formed as a result of combusting a combustible fuel, may be mixed with the feedstock gas. At high-enough temperatures, the mixing of the hot fluid with the feedstock gas, and the transfer of thermal energy from the hot fluid to the feedstock gas, is sufficient to cause the feedstock gas to break down and decompose.

[0004] Feedstock decomposition typically occurs in a reaction chamber, and prior to the decomposition the feedstock can be delivered to the reaction chamber, and the products of the decomposition can be extracted from the reaction chamber, using rotary valves. A rotary valve includes a rotor that rotates relative to a stator. The rotor and the stator each have openings, and the rotation of the rotor relative to the stator causes the openings to periodically align.

[0005] The pressure differential generated during rotation of the rotor can lead to deflection or separation of the rotor from the stator. This problem is exacerbated by the fact that the high temperatures of the feedstock and the reaction products can lead to significant dimensional changes.

[0006] Springs I preload mechanisms have been used to prevent separation of the rotor from the stator. However, this can lead to friction/adhesion issues during start-up and after long periods of downtime. For example, the torque required to overcome the static friction between the rotor and the stator can be much larger than the system was designed to handle, and can damage both the sealing interfaces and the rotational components.

[0007] Some strategies that attempt to solve the friction/adhesion issues include the use of heat treatments or special materials. While these may minimize the effects of the friction/adhesion issues, valves incorporating such heat treatments or special materials will still suffer from a “stick-slip” mode.

Summary

[0008] According to a first aspect of the disclosure, there is provided a valve assembly comprising: a rotary valve comprising a rotor and a stator, and defining a first axis of rotation; gearing connected to the rotor; and a drive mechanism connected to the gearing, wherein operation of the drive mechanism drives rotation of the gearing which generates: a rotational force about the first axis of rotation for driving rotation of the rotor relative to the stator; and an axial force along the first axis of rotation for maintaining contact between the rotor and the stator during the rotation of the rotor relative to the stator.

[0009] The gearing may define a second axis of rotation that is the same as the first axis of rotation.

[0010] The gearing may comprise a helical gear.

[0011] The drive mechanism may comprise a motor.

[0012] According to a further aspect of the disclosure, there is provided a method of operating a rotary valve comprising a rotor and a stator, and defining a first axis of rotation, wherein the method comprises: rotating gearing connected to the rotor to generate: a rotational force about the first axis of rotation that drives rotation of the rotor relative to the stator; and an axial force along the first axis of rotation that maintains contact between the rotor and the stator during the rotation of the rotor relative to the stator.

[0013] According to a further aspect of the disclosure, there is provided a feedstock reactor comprising: a reaction chamber; and at least one valve assembly for permitting feedstock to enter the reaction chamber or for permitting one or more reaction products, formed as a result of decomposition of the feedstock inside the reaction chamber, to exit the reaction chamber, comprising: a rotary valve comprising a rotor and a stator, and defining a first axis of rotation; gearing connected to the rotor; and a drive mechanism connected to the gearing, wherein operation of the drive mechanism drives rotation of the gearing which generates: a rotational force about the first axis of rotation for driving rotation of the rotor relative to the stator; and an axial force along the first axis of rotation for maintaining contact between the rotor and the stator during the rotation of the rotor relative to the stator.

[0014] The reaction chamber may comprise one or more inlets for flow of the feedstock into the reaction chamber. The at least one valve assembly may be connected to the one or more inlets.

[0015] The reaction chamber may comprise one or more outlets for flow of the one or more reaction products out of the reaction chamber. The at least one valve assembly may be connected to the one or more outlets.

[0016] The feedstock reactor may further comprise: a combustion chamber connected to the reaction chamber and for receiving a fuel and an oxidant; and at least one igniter for triggering combustion of the fuel in the presence of the oxidant.

[0017] The feedstock reactor may further comprise: a controller, comprising circuitry, configured to operate valving, one or more compressors, and the at least one igniter to: introduce the feedstock into the reaction chamber; introduce the fuel and the oxidant into the combustion chamber; combust, in the combustion chamber, the fuel and the oxidant to form one or more combustion products that flow into the reaction chamber and mix with the feedstock, wherein, as a result of the mixing of the one or more combustion products with the feedstock, energy is transferred from the one or more combustion products to the feedstock and causes the feedstock to decompose; and extract the one or more reaction products from the reaction chamber, wherein introducing the feedstock into the reaction chamber, or extracting the one or more reaction products from the reaction chamber, comprises controlling the at least one valve assembly.

[0018] According to a further aspect of the disclosure, there is provided a method of operating a feedstock reactor, comprising: flowing a feedstock into a reaction chamber of the feedstock reactor; mixing an energy fluid with the feedstock, wherein, as a result of the mixing of the energy fluid with the feedstock, energy is transferred from the energy fluid to the feedstock and causes the feedstock to decompose and thereby form one or more reaction products; and extracting the one or more reaction products from the reaction chamber, wherein flowing the feedstock into the reaction chamber, or extracting the one or more reaction products from the reaction chamber, comprises operating a rotary valve, comprising a rotor and a stator, and defining a first axis of rotation, by: rotating a gearing connected to the rotor to generate: a rotational force about the first axis of rotation that drives rotation of the rotor relative to the stator; and an axial force along the first axis of rotation that maintains contact between the rotor and the stator during the rotation of the rotor relative to the stator.

[0019] Mixing the energy fluid with the feedstock may comprise: combusting a fuel with an oxidant to generate one or more combustion products; and flowing the one or more combustion products into the reaction chamber to mix with the feedstock.

[0020] The fuel may comprise at least some of the feedstock.

[0021] The oxidant may comprise pure oxygen or air.

[0022] The feedstock may comprise a hydrocarbon.

[0023] A temperature of the feedstock may be from 800 K to 1200 K.

[0024] A temperature of the one or more reaction products may be from 1200 K to 1600 K.

[0025] This summary does not necessarily describe the entire scope of all aspects. Other aspects, features, and advantages will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments.

Drawings

[0026] Embodiments of the disclosure will now be described in detail in conjunction with the accompanying drawings of which:

[0027] FIGS. 1A and 1 B are, respectively, end-on and cross-sectional views of a rotary valve according to an embodiment of the disclosure;

[0028] FIGS. 2A-2C illustrate deflection and separation of a rotor from a stator;

[0029] FIG. 3 is a plot illustrating the effect of static friction, and shows friction force as a function of velocity;

[0030] FIG. 4 is a schematic diagram of a valve assembly according to an embodiment of the disclosure; and

[0031] FIG. 5 is a schematic diagram of a feedstock reactor being used to decompose a feedstock, according to an embodiment of the disclosure. Detailed Description

[0032] The present disclosure seeks to provide a novel valve assembly and a novel feedstock reactor. While various embodiments of the disclosure are described below, the disclosure is not limited to these embodiments, and variations of these embodiments may well fall within the scope of the disclosure which is to be limited only by the appended claims.

[0033] Helical gears produce an axial force when transmitting torque. This is typically considered a disadvantage. However, according to embodiments of the disclosure, the axial force may be used, during operation of a rotary valve, to maintain contact between the valve’s rotor and stator. For example, the helical gear may be connected to the valve’s rotor, and the axial force acting on the rotor, as a result of turning the helical splines of the gear, may balance the force generated by any pressure differential produced during operation of the valve.

[0034] Advantageously, the use of a helical gear in this fashion may urge the rotor into contact with the stator, or otherwise maintain contact between the rotor and the stator. This may in turn avoid the need to use springs or other preloading mechanisms, as well as heat treatments or special materials, in order to maintain contact between the rotor and stator during operation of the valve.

[0035] Furthermore, the use of a helical gear may address friction/adhesion issues that may be encountered when using springs or other preloading mechanisms. For example, the axial force generated by rotation of a helical gear is only produced in response to rotation of the helical gear. When the helical gear is at rest, no axial force is produced. Therefore, at start-up of the valve (i.e. , when commencing rotation of the valve), especially after a relatively long period of idleness, static friction between the rotor and the stator may be minimized. FIG. 3 shows an example of static friction that may be encountered at start-up of a rotary valve. As can be seen, static friction is greatest just before the valve begins to rotate, and then decreases as the valve’s rotation picks up speed.

[0036] Therefore, according to embodiments of the disclosure, there is described a valve assembly comprising a rotary valve having a rotor and a stator, and defining a first axis of rotation. Gearing is connected to the rotor, and a motor or other drive mechanism is connected to the gearing. Operation of the motor drives rotation of the gearing which generates a rotational force, about the first axis of rotation, for driving rotation of the rotor relative to the stator. Rotation of the gearing further generates an axial force, along the first axis of rotation, for maintaining contact between the rotor and the stator during the rotation of the rotor relative to the stator. The gearing may comprise a helical gear, and the gearing may define a second axis of rotation that is the same as the first axis of rotation.

[0037] Generally, a helical gear may be any gear that, during rotation, produces an axial force along its axis of rotation, in addition to a rotational force about its axis of rotation. Helical gears may include gears with curved or sinusoidal-shaped teeth or splines, or otherwise helically- shaped teeth or splines. More generally, the disclosure extends to any gearing that may include a helical gear or any other gear or set of gears that is capable of producing an axial force in response to rotation of the gearing.

[0038] FIGS. 1A and 1 B show a rotary valve 10 comprising a rotor 14 adjacent a stator 16, according to an embodiment of the disclosure. Rotor 14 includes at least one opening 12 formed therein, and stator 16 also includes at least one opening 18 formed therein. During rotation of rotor 14, openings 12 and 18 periodically align to permit fluid flow therethrough (for example, fluid may flow from the right-hand side of rotary valve 10 to the left-hand side of rotary valve 10, using FIG. 1 B as the reference).

[0039] FIGS. 2A-2C illustrate deflection (FIG. 2B) and separation (FIG. 20) of rotor 14 from stator 16. In particular, as can be seen in FIG. 2A, a pressure differential exists between rotor 14 and stator 16, with fluid on the right-hand side of rotary valve 10 exerting a pressure on rotor 14. If this pressure differential becomes too great, rotor 14 may deflect from stator 16 (as can be seen in FIG. 2B), or rotor 14 may even separate from stator 16 (as can be seen in FIG. 20).

[0040] In FIG. 4, there is shown a valve assembly 100 according to an embodiment of the disclosure. Valve assembly 100 includes a motor 20 or other driving mechanism operatively connected to a helical gear 25 comprising a female helical spline 22. A male helical spline 24 is received in female helical spline 22. The output of male helical spline 24 is operatively connected to rotary valve 10 comprising rotor 14 operable to rotate relative to stator 16. According to alternative embodiments (not shown), male helical spline 24 may be attached to motor 20, and female helical spline 22 may be attached to rotor 14 with the same effect.

[0041] As can be seen, operation of motor 20 rotates female helical spline 22, thereby rotating male helical spline 24 and in turn generating an axial force 26 along the axis of rotation of male helical spline 24. Rotation of male helical spline 24 results in rotation of rotor 14. Furthermore, axial force 26 acts on rotor 14 to maintain contact between rotor 14 and stator 16 during rotation of rotor 14, thereby reducing the risk of deflection or separation of rotor 14 from stator 16. [0042] Turning to FIG. 5, there is shown a process of thermal pyrolysis using a feedstock reactor 150, according to an embodiment of the disclosure. According to the embodiment of FIG. 5, one or more valve assemblies as described herein are used to control the phased delivery of feedstock to a reaction chamber, and/or the phased extraction of reaction products from the reaction chamber. Feedstock reactor 150, and the method of using feedstock reactor 150, may include any of the embodiments described in US Patent Publication No. 2022/0203326, incorporated herein by reference in its entirety.

[0043] Feedstock reactor 150 includes a reaction chamber 64 that is filled with a feedstock 66 (such as a hydrocarbon, such as methane) using a valve assembly 100a which may be a valve assembly as described above. A fuel 50 (which may have the same composition as the feedstock) and an oxidant 54 (such as oxygen or air) are injected into a combustion chamber 52. As a result, a combustible gas mixture is formed within combustion chamber 52. According to some embodiments, the fuel and the oxidant may be pre-mixed, and the combustible gas mixture alone may be injected or otherwise delivered into combustion chamber 52.

[0044] Once combustion chamber 52 is filled with the combustible gas mixture, and once reaction chamber 64 is loaded with feedstock 66, an igniter 62 is triggered to cause combustion of the combustible gas mixture, forming combustion products that flow under pressure into reaction chamber 64 filled with feedstock 66. Thermal energy is transferred from the combustion products to feedstock 66. Energy is also transferred from the hot combustion products to feedstock 66 via dynamic compression of feedstock 66 as a result of the pressure increasing within reaction chamber 64 in response to the flow of hot, pressurized combustion products into reaction chamber 64. Past a certain point, the increase in the temperature of feedstock 66 is sufficient to drive decomposition or pyrolysis of feedstock 66. In the case of methane, for example, the decomposition takes the following form:

CH4 + energy — > C + 2H2

The reaction products 68 that are produced by the pyrolysis are then extracted from reaction chamber 64, using a valve assembly 100b which may be a valve assembly as described above.

[0045] According to some embodiments, reaction chamber 64 may be connected to multiple such combustion chambers 52. According to some embodiments, one or more injection nozzles (not shown), that extend, from combustion chamber 52 and, optionally, partially into reaction chamber 64, may be used to assist in the delivery of the hot combustion products to reaction chamber 64. For example, the ends of each injection nozzle may comprise multiple openings that allow the hot combustion products to be “sprayed” or injected along multiple directions into reaction chamber 64, thereby improving the mixing of the hot combustion products with feedstock 66. According to some embodiments, a portion of reaction products 68 is recycled back to reaction chamber 64 for future reaction cycles. In the case of methane pyrolysis, reaction products 68 may comprise one or more of hydrogen, nitrogen, and carbon, the unwanted products are primarily carbon dioxide, nitrogen, and water, and the recycled gas mixture comprises primarily unreacted natural gas, hydrogen, nitrogen, and carbon monoxide.

[0046] Operation of reactor 150’s various valves (including valve assemblies 100a and 100b) may be controlled by a suitable controller (such as a microprocessor) comprising circuitry. The controller (not shown), or some other controller, may control the loading of combustion chamber 52 and reaction chamber 64 by controlling compressors or similar devices, for example.

[0047] The use of helical gears to drive operation of the rotary valves of valve assemblies 100a and 100b may be particularly useful when delivering feedstock 66 to reaction chamber 64, and when extracting reaction products 68 from reaction chamber 64. In particular, the high temperatures of feedstock 66 and reaction products 68 may affect the ability of the rotors to seal against the stators of the rotary valves. For instance, the feedstock temperature may range from 800 - 1200 K, and the reaction product temperature may range from 1200 - 1600 K. Therefore, the axial forces generated by rotation of the helical gears of valve assemblies 100a and 100b may improve the sealing between the rotors and their respective stators.

[0048] According to some embodiments, a single rotary valve with multiple ports can be used with multiple feedstock reactors 150 operating in tandem.

[0049] While the disclosure has been presented in the context of a helical gear generating an axial force that is aligned with the axis of rotation of the rotor, the disclosure extends to any form of connection between gearing and the rotor in which the axial force generated as a result of rotation of the gearing translates into a corresponding axial force aligned with the rotor’s axis of rotation. For example, the gearing and the rotor may be off-set from one another, provided that a suitable drive mechanism is used to transfer the direction of the axial force generated by the gearing to that of the axis of rotation of the rotor.

[0050] Aligning the gearing with the rotor may be advantageous since this may assist in addressing potential dimensional changes in the rotor/stator in the axial direction as the rotor/stator warms up to operating temperature. In the case of a helical gear, this can be addressed by providing some space between female helical spline 22 and male helical spline 24, as shown in FIG. 4.

[0051] According to some embodiments, instead of using combustion products to decompose the feedstock, another “energy fluid” may be used. An energy fluid may be a fluid that has sufficient thermal energy to drive decomposition of the feedstock when the energy fluid is mixed with the feedstock.

[0052] The word “a” or “an” when used in conjunction with the term “comprising” or “including” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one” unless the content clearly dictates otherwise. Similarly, the word “another” may mean at least a second or more unless the content clearly dictates otherwise.

[0053] The terms “coupled”, “coupling” or “connected” as used herein can have several different meanings depending on the context in which these terms are used. For example, as used herein, the terms coupled, coupling, or connected can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via a mechanical element depending on the particular context. The term “and/or” herein when used in association with a list of items means any one or more of the items comprising that list.

[0054] As used herein, a reference to “about” or “approximately” a number or to being “substantially” equal to a number means being within +/- 10% of that number.

[0055] Use of language such as “at least one of X, Y, and Z,” “at least one of X, Y, or Z,” “at least one or more of X, Y, and Z,” “at least one or more of X, Y, and/or Z,” or “at least one of X, Y, and/or Z,” is intended to be inclusive of both a single item (e.g., just X, or just Y, or just Z) and multiple items (e.g., {X and Y}, {X and Z}, {Y and Z}, or {X, Y, and Z}). The phrase “at least one of” and similar phrases are not intended to convey a requirement that each possible item must be present, although each possible item may be present.

[0056] While the disclosure has been described in connection with specific embodiments, it is to be understood that the disclosure is not limited to these embodiments, and that alterations, modifications, and variations of these embodiments may be carried out by the skilled person without departing from the scope of the disclosure. [0057] It is furthermore contemplated that any part of any aspect or embodiment discussed in this specification can be implemented or combined with any part of any other aspect or embodiment discussed in this specification.

Claims

1 . A valve assembly comprising: a rotary valve comprising a rotor and a stator, and defining a first axis of rotation; gearing connected to the rotor; and a drive mechanism connected to the gearing, wherein operation of the drive mechanism drives rotation of the gearing which generates: a rotational force about the first axis of rotation for driving rotation of the rotor relative to the stator; and an axial force along the first axis of rotation for maintaining contact between the rotor and the stator during the rotation of the rotor relative to the stator.

2. The valve assembly of claim 1 , wherein the gearing defines a second axis of rotation that is the same as the first axis of rotation.

3. The valve assembly of claim 1 or 2, wherein the gearing comprises a helical gear.

4. The valve assembly of any one of claims 1-3, wherein the drive mechanism comprises a motor.

5. A method of operating a rotary valve comprising a rotor and a stator, and defining a first axis of rotation, wherein the method comprises: rotating gearing connected to the rotor to generate: a rotational force about the first axis of rotation that drives rotation of the rotor relative to the stator; and an axial force along the first axis of rotation that maintains contact between the rotor and the stator during the rotation of the rotor relative to the stator.

6. The method of claim 5, wherein the gearing defines a second axis of rotation that is the same as the first axis of rotation.

7. The method of claim 5 or 6, wherein rotating the gearing comprises rotating a helical gear.

8. A feedstock reactor comprising: a reaction chamber; and at least one valve assembly for permitting feedstock to enter the reaction chamber or for permitting one or more reaction products, formed as a result of decomposition of the feedstock inside the reaction chamber, to exit the reaction chamber, comprising: a rotary valve comprising a rotor and a stator, and defining a first axis of rotation; gearing connected to the rotor; and a drive mechanism connected to the gearing, wherein operation of the drive mechanism drives rotation of the gearing which generates: a rotational force about the first axis of rotation for driving rotation of the rotor relative to the stator; and an axial force along the first axis of rotation for maintaining contact between the rotor and the stator during the rotation of the rotor relative to the stator.

9. The feedstock reactor of claim 8, wherein: the reaction chamber comprises one or more inlets for flow of the feedstock into the reaction chamber; and the at least one valve assembly is connected to the one or more inlets.

10. The feedstock reactor of claim 8 or 9, wherein: the reaction chamber comprises one or more outlets for flow of the one or more reaction products out of the reaction chamber; and the at least one valve assembly is connected to the one or more outlets.

11. The feedstock reactor of any one of claims 8-10, further comprising: a combustion chamber connected to the reaction chamber and for receiving a fuel and an oxidant; and at least one igniter for triggering combustion of the fuel in the presence of the oxidant.

12. The feedstock reactor of claim 11 , further comprising: a controller, comprising circuitry, configured to operate valving, one or more compressors, and the at least one igniter to: introduce the feedstock into the reaction chamber; introduce the fuel and the oxidant into the combustion chamber; combust, in the combustion chamber, the fuel and the oxidant to form one or more combustion products that flow into the reaction chamber and mix with the feedstock, wherein, as a result of the mixing of the one or more combustion products with the feedstock, energy is transferred from the one or more combustion products to the feedstock and causes the feedstock to decompose; and extract the one or more reaction products from the reaction chamber, wherein introducing the feedstock into the reaction chamber, or extracting the one or more reaction products from the reaction chamber, comprises controlling the at least one valve assembly.

13. The feedstock reactor of any one of claims 8-12, wherein the gearing defines a second axis of rotation that is the same as the first axis of rotation.

14. The feedstock reactor of any one of claims 8-13, wherein the gearing comprises a helical gear.

15. A method of operating a feedstock reactor, comprising: flowing a feedstock into a reaction chamber of the feedstock reactor; mixing an energy fluid with the feedstock, wherein, as a result of the mixing of the energy fluid with the feedstock, energy is transferred from the energy fluid to the feedstock and causes the feedstock to decompose and thereby form one or more reaction products; and extracting the one or more reaction products from the reaction chamber, wherein flowing the feedstock into the reaction chamber, or extracting the one or more reaction products from the reaction chamber, comprises operating a rotary valve, comprising a rotor and a stator, and defining a first axis of rotation, by: rotating a gearing connected to the rotor to generate: a rotational force about the first axis of rotation that drives rotation of the rotor relative to the stator; and an axial force along the first axis of rotation that maintains contact between the rotor and the stator during the rotation of the rotor relative to the stator.

16. The method of claim 15, wherein mixing the energy fluid with the feedstock comprises: combusting a fuel with an oxidant to generate one or more combustion products; and flowing the one or more combustion products into the reaction chamber to mix with the feedstock.

17. The method of claim 15 or 16, wherein the fuel comprises at least some of the feedstock.

18. The method of any one of claims 15-17, wherein the oxidant comprises pure oxygen or air.

19. The method of any one of claims 15-18, wherein the feedstock comprises a hydrocarbon.

20. The method of any one of claims 15-19, wherein a temperature of the feedstock is from 800 K to 1200 K.

21. The method of any one of claims 15-20, wherein a temperature of the one or more reaction products is from 1200 K to 1600 K.

22. The method of any one of claims 15-21 , wherein the gearing defines a second axis of rotation that is the same as the first axis of rotation.

23. The method of any one of claims 15-22, wherein rotating the gearing comprises rotating a helical gear.