Photoreactor design for thermodynamically limited chemical reactions

Abstract

Disclosed herein is a photoreactor design having an optically accessible reactor chamber with a short gas flow residence time for performing a gas-phase catalytic reaction under light irradiation. The vertically arranged reactor is provided with an illumination light source and a horizontally arranged thin layer of catalyst bed supported on a gas-permeable boundary plate through which the gas passes vertically, and the incident photons from the illumination light source are perpendicular to the horizontally arranged thin layer of catalyst bed. The described technology is intended to enable, in plants powered by heat, many industrially relevant chemical reactions to proceed under light irradiation on the surface of metal photocatalysts with an efficiency and selectivity that exceed the efficiency defined by the thermodynamic equilibrium in conventional thermal catalytic reactions.

Description

Technical Field

[0001] Field

[0001] The present disclosure relates to the field of industrial chemical production using photocatalytic reactors, and more particularly to the design of photoreactors for thermodynamically limited chemical reactions.

Background Art

[0002] Background

[0002] Conventional systems for gas-phase thermally driven heterogeneous catalysis on supported metal nanoparticles (NPs) are limited in their efficiency by thermal equilibrium and the linear energy dependence of the elementary processes that control overall reactivity. A typical thermocatalytic gas-phase reactor features an axially oriented catalyst bed integrated into a cylindrical reactor made of high-alloy steel, and the height-to-diameter ratio of the catalyst bed is typically much greater than 1 (>1), resulting in a relatively long residence time (the average time that gas-phase reaction molecules remain in the reactor chamber).

[0003]

[0003] Shortening the residence time (i.e., minimizing the contact time between reactants and catalyst) has been thought to improve productivity in certain reactions. Therefore, in some recent reactor designs that mainly utilize fluidized catalyst beds, attempts have been made to shorten the residence time. Examples of such designs are described in U.S. Patent Nos. 5,605,551, 5,240,592, and 5,110,452, and European Patent Application Publication No. 0485378A1. However, like typical cylindrical thermocatalytic reactors, each of the aforementioned reactors is also thermally driven, and thus still suffers from efficiency limitations due to thermal equilibrium and the linear energy dependence of the elementary processes that control overall reactivity.

[0004] [

[0004] ] Photocatalysis using an optically active metal catalyst under photon irradiation in the spectrum from ultraviolet to visible light has shown an improvement in energy efficiency over conventional thermal catalysis. By combining the photoinduced electron effect and the thermal effect, the photocatalytic reaction promotes a reaction rate higher than that of a pure thermal catalytic reaction and opens reaction channels that cannot be reached by heat alone. By coupling light to the reaction pathway, non-thermal (electronic) energy transfer is brought about that accelerates dissociation and desorption events by inducing vibrational excitation and electronic excitation in surface adsorbates. These surface adsorbates are promoted as reaction intermediates to a new potential energy surface in an excited state with a lower energy barrier. Therefore, the energy requirement is lower than that of a conventional thermal catalytic reaction. The design of a conventional thermal catalytic reactor is inappropriate for a photocatalytic reaction. Therefore, an improved design of a photocatalytic reactor is desired.

[0005] Brief Description of the Drawings [

[0005] ] The accompanying drawings are incorporated to provide a further understanding of the systems, devices, apparatuses, and / or methods of the present disclosure, and constitute a part of this specification. The drawings are not necessarily to scale, and the sizes of various elements may be distorted for clarity and / or presented as a simplified representation to facilitate understanding. The drawings illustrate one or more embodiments of the present disclosure and, together with the description, serve to explain the principles and operations of the present disclosure.

Brief Description of the Drawings

[0006]

Fig. 1A

[0006] ] It is a simplified longitudinal sectional view showing a vertically arranged photoreactor according to a first exemplary cylindrical embodiment.

Fig. 1B

[0007] It is a simplified top view of a first exemplary cylindrical embodiment of the photoreactor shown in FIG. 1A.

Fig. 1C

[0008] It is a simplified top view of an exemplary rectangular modification of the photoreactor shown in FIG. 1A.

Fig. 1D

[0009] It is a simplified top view of an exemplary hexagonal modification of the photoreactor shown in FIG. 1A.

Fig. 2

[0010] It is a graph showing the experimental results of photocatalytic ammonia synthesis using a photoreactor according to a first exemplary embodiment.

Fig. 3

[0011] It is a graph showing the thermodynamic equilibrium of ammonia synthesis according to Haber, 1920.

Mode for Carrying Out the Invention

[0007] Detailed Description

[0012] Exemplary systems, devices, apparatuses, and / or methods are described herein. It should be understood that the term "exemplary" is used in the sense of "serving as an example, instance, or illustration". Any embodiment or feature described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or features unless so stated. Accordingly, other embodiments may be utilized and other changes may be made without departing from the scope of the subject matter presented herein. The aspects described herein are not limited to a particular embodiment, apparatus, or configuration and are, of course, subject to change. It should be readily understood that the aspects of the present disclosure can be arranged, replaced, combined, separated, and designed in a variety of different configurations as generally described herein and shown in the figures. Also, it should be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting unless otherwise specifically defined herein.

[0008]

[0013] Throughout this specification, unless the context requires otherwise, the words "comprise", "comprising", "include", "including", "has", and "having" and variations thereof (e.g., "comprises", "comprising", "includes", "including", "has", and "having") are to be construed as including the stated element, feature, element, or step, or group of elements, features, elements, or steps, but not as excluding other elements, features, elements, or steps, or group of elements, features, elements, or steps.

[0009]

[0014] Furthermore, unless the context requires otherwise, the features shown in each of the figures can be used in combination with each other. Thus, it should be understood that not all of the features shown are necessary for each embodiment, and the figures should generally be regarded as depicting the component aspects of one or more overall embodiments.

[0010]

[0015] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0011]

[0016] In this specification, ranges can be expressed as from "about" a particular value and / or to "about" another particular value. When such a range is expressed, another aspect includes from one particular value and / or to another particular value. Similarly, when values are expressed as approximations by use of the antecedent "about", the particular value forms another aspect. Further, it should be understood that each of the endpoints of a range is significant both in relation to the other endpoint and in isolation from the other endpoint.

[0012]

[0017] Any enumeration of elements, blocks, or steps in this specification or the claims is for clarity purposes only. Accordingly, such enumeration should not be construed as requiring or implying that these elements, blocks, or steps follow a particular arrangement or are performed in a particular order.

[0013] I. Overview

[0018] The technology disclosed herein relates to an electrophotochemical reaction chamber having a thin catalyst bed and a short gas flow residence time, suitable for performing a gas-phase catalytic reaction under light irradiation. The input energy for catalyzing the reaction is supplied from light generated by one or more lighting devices such as, for example, an array of light-emitting diodes (LEDs) or other solid-state lighting devices, an arc lamp, an ultraviolet (UV) bulb, etc. The lighting device is preferably powered by renewable electricity to reduce the carbon footprint compared to conventional thermal power plants that require the combustion of fossil fuels, but this is not necessary.

[0014]

[0019] The appended claims set forth the scope of the invention for which protection is sought, but the various exemplary embodiments described herein are directed to a vertically arranged photoreactor having one or more of the following features: · A photocatalyst bed having a horizontally arranged thin layer of photocatalyst, where, for example, the thin layer has a thickness of 1 cm, or 2 cm, or 3 cm, or a thickness between 1 cm and 3 cm including the boundaries, or a thickness greater than 1 cm, or a thickness less than 3 cm. The thin layer has, for example, a cylindrical shape in a cylindrical reactor and a prismatic shape in a prismatic reactor. Generally, the shape of the thin layer is similar or identical to the shape of the reactor chamber of the photoreactor with reduced size (mainly thickness). · The photocatalyst bed extends across its full (or substantially its full) radius, width, length, or other lateral dimension of the horizontal reactor axis, and the thickness-to-radius ratio is less than 1.0. · The reaction gas is passed vertically through the horizontally arranged photocatalyst bed from the top surface to the bottom surface. · The photocatalyst bed is supported by a gas-permeable plate. · The photocatalyst bed is fixed and not fluidized. · A horizontally arranged illumination light source, such as an LED module (or other solid-state illumination light source), an arc lamp, an IR bulb, or other types of illumination light sources, is provided for photocatalyst irradiation onto the photocatalyst bed through an optically transparent window. · The active part (photon-emitting part) of the illumination light source has a diameter or other lateral dimension that is approximately (i.e., almost) equal to the inner diameter of the photoreactor and the diameter of the photocatalyst bed.

[0015]

[0020] A thin layer of the catalyst bed has been conventionally adapted for use in a conventional (non-photocatalytic) reactor in which the catalyst bed is arranged in the direction of flow (lateral or horizontal gas flow), as opposed to the gas flow (i.e., vertical flow as utilized in the exemplary embodiments currently disclosed) passing through the catalyst bed. See, for example, the reactor described in U.S. Patent No. 5,484,576. Alternatively, an axial thin-layer thermocatalytic reactor having a relatively long catalyst bed arranged vertically has been developed to have a gas flow perpendicular to the catalyst bed. See, for example, the non-photocatalytic reactors described in U.S. Patent No. 8,101,140 and U.S. Patent Application Publication No. 2011 / 0133126A1. The above-described conventional reactor design configurations are not suitable for performing an efficient photocatalytic reaction using a photoactive material under light irradiation.

[0016]

[0021] The presently described exemplary embodiments can address a number of technical challenges related to the production of commodity chemicals and fuels on an industrially relevant scale. In the path towards sustainability, the techniques described herein can be applied in the direction of realizing low-cost, zero-emission chemical manufacturing by providing a light-driven solution as an alternative to conventional oil-based thermal catalysts that is in line with the climate goals of the Paris Agreement. Further, the disclosed techniques can address long-standing challenges in the catalytic reactions of several chemically important reactions that are energy, industrial, and environmentally important by leveraging significantly milder operating conditions compared to conventional thermochemical plants, by providing a path beyond the thermodynamic equilibrium of the reaction, and by promoting reaction rates beyond those defined by the heat balance. This can result in reduced energy costs and potentially improved efficiency of chemical conversion.

[0017]

[0022] The current potential uses of the presently disclosed technology are in low-temperature photocatalytic reactions for reactions plagued by kinetically and thermodynamically opposing demands, such as ammonia (NH3) synthesis from N2 and H2, and reactions where it is important to control product selectivity and catalyst stability, such as the partial dehydrogenation of alkanes, ethane, and propane to ethylene and propylene, respectively. Ammonia, ethylene, and propylene belong to the most valuable basic chemical commodities globally, but the current processes for manufacturing them are extremely energy-intensive. Over 96% of the world's ammonia production utilizes the Haber-Bosch (HB) process, and according to some estimates, this process accounts for approximately 2% of the world's fossil energy use and over 1.5% of the world's CO2 emissions. The sustainable production of green ammonia by the technology currently described can enable the transition from fossil fuels to a zero-carbon energy industry while assisting in reducing carbon dioxide emissions. Similarly, the industrial production of propylene and ethylene is the second and third largest carbon emission sources in the chemical industry after ammonia. In these two reactions, the harsh reaction conditions also promote particle sintering, leading to undesirable side reactions such as coke formation and hydrocracking, resulting in impaired product efficiency, stability, and selectivity. The exemplary embodiments described herein may enable the production of ethylene and propylene that is more sustainable and selective than conventional systems and methods. Other potential uses may also be achievable using the exemplary photoreactor designs and features described herein.

[0018] II. Exemplary Photoreactor Design

[0023] Throughout this specification and the appended claims, terms or phrases such as "vertical", "vertically disposed", "top", "bottom", "upper", "lower", "above", "below", "higher than", "lower than", "horizontally", "horizontally disposed", and other relative descriptions are to be interpreted in relation to a predefined frame of reference, such as the main source of gravity (e.g., the Earth) or the direction in which the product gas exits the reactor. Thus, for example, "vertically disposed" generally means the arrangement of adjacent components (e.g., "horizontal" layers) extending away in a direction generally orthogonal to the surface of the Earth (or the direction in which the product gas exits the reactor), where the relatively "lower" component is closer to the surface of the Earth (or closer to the direction in which the product gas exits the reactor) than the relatively "higher" component. The "top" of such an arrangement or component should be interpreted as the location furthest from the surface of the Earth, or almost the furthest (or the furthest or almost the furthest from the direction in which the product gas exits the reactor), while the "bottom" is the opposite. As the antonym of "vertically disposed", the phrase "horizontally disposed" means the arrangement of adjacent components whose collective arrangement (e.g., defined by the central axis passing through the arrangement) is generally in the same plane as the surface of the Earth or parallel to the surface of the Earth (or orthogonal or perpendicular to the direction in which the product gas exits the reactor). Similarly, a "horizontally disposed" component is one that has its longest linear dimension (e.g., diameter, length, or width) generally in the same plane as the surface of the Earth or parallel to the surface of the Earth (or orthogonal or perpendicular to the direction in which the product gas exits the reactor), as compared to the linear dimension in the vertical direction (e.g., height) that is orthogonal to the surface of the Earth (and in the same straight line as the direction in which the product gas exits the reactor).

[0019]

[0024] Figure 1A is a simplified longitudinal cross-sectional view showing a photoreactor 100 for an industrially relevant chemical reaction according to a first exemplary embodiment. Although described herein as a "photoreactor", the illustrated photoreactor 100 is a photoreactor chamber and components as shown and described below, with other external components and systems omitted for clarity. Examples of omitted external components and systems that may be included in a photoreactor used for the production of industrial chemicals include gas lines / tubes / piping, valves, pumps, sensors, heaters, chillers, condensers, storage / supply tanks, power supplies, control systems, safety devices, and post-production devices and / or systems. Candidate reactions for the photoreactor 100 include, but are not limited to, ammonia synthesis, the experimental results of which are described with reference to FIG. 2, and the partial dehydrogenation of alkanes, ethane, and propane to ethylene and propylene, which is described in more detail below.

[0020]

[0025] For the example of FIG. 1A, the photoreactor 100 is generally described as being cylindrical (i.e., cylindrical reactor chambers and other cylindrical components are stacked to form a cylinder having a circular cross-section when viewed from above, as shown in FIG. 1B). However, the photoreactor 100 may alternatively have a different shape, such as a three-dimensional shape (e.g., a rectangular parallelepiped) having a rectangular, square, or other regular or irregular polygonal or elliptical (or other) cross-section, which may have a consistent width (e.g., diameter) throughout the height of the photoreactor 100, but does not necessarily have to. FIG. 1B shows a simplified top view of the exemplary cylindrical photoreactor 100 shown in FIG. 1A, and FIGS. 1C and 1D show simplified top views of rectangular and hexagonal variations of the photoreactor shown in FIG. 1A, respectively. FIGS. 1B, 1C, and 1D also show exemplary arrangements and numbers of reaction gas inlets and coolant inlets and outlets, which are described in more detail below with respect to FIG. 1A.

[0021]

[0026] The photoreactor 100 includes a vertically disposed body 102 made of a high-pressure resistant material (e.g., evaluated for pressures of at least 4 standard atmospheres (405.3 kPa)), such as one or more structural alloys of steel or nickel, titanium, aluminum, or quartz. As described above, in the example of FIG. 1A, the body 102 (and some or most other components of the photoreactor 100) is cylindrical, but in non-cylindrical variations, according to alternative exemplary embodiments, other components may generally have a shape similar or related to the shape of the reactor body (e.g., the same cross-section). Located within and / or forming part of the cylindrical body 102 of the vertically disposed photoreactor 100 are a cylindrical photoreactor chamber 104, an illumination light source 106, an optically transparent window 108, a product gas compartment 110, reaction gas inlets 112a and 112b for receiving respective reaction gas feed streams Ra and Rb, and a product gas outlet 114 for outputting product gas P. The photoreactor chamber 104 further includes a chamber section 116 and a thin layer 118 of catalyst bed on a gas permeable plate 120.

[0022]

[0027] In the view of FIG. 1A, the body 102 substantially constitutes the full height of the photoreactor 100, and other components such as the photoreactor chamber 104, the illumination light source 106, the window 108, and the product gas compartment 110 are shown stacked within the body 102. In such a configuration, a relatively strict physical tolerance is required, perhaps using spacer rings or other positioning mechanisms, to maintain the illustrated physical spacing relationship between the components. In an alternative vertical arrangement configuration, the body 102 constitutes only a part of the photoreactor chamber 104 and the product gas compartment 110, while the window 108 and the illumination light source 106 are stacked on top of the body 102, resulting in a sandwich structure of the photoreactor 100. In this alternative configuration, components such as the window 108 and the illumination light source 106 may be designed to have the same diameter as or slightly larger than the outer diameter of the body 102, such that the window 108 is positioned on top of the upper circular lip of the body 102 and the light source 106 is positioned on top of the window 108. In yet another alternative configuration, the interior of the body 102 includes the photoreactor chamber 104, the window 108, and the product gas compartment 110, and the illumination light source 106 is positioned on top of the upper circular lip of the body 102, which may be in the same plane as the upper surface of the window 108 or may extend beyond the upper surface of the window 108, as will be described in more detail below. In any of the foregoing alternative configurations, the vertically stacked components of the photoreactor 100 can be clamped or otherwise fixed to each other by adhesives and / or mechanical fasteners, etc. Further, as described above, in the case of the non-cylindrical body 102, instead of having a circular cross-sectional shape with a corresponding diameter, the stacked components may have other cross-sectional shapes and length-width dimensions. However, similar concepts still apply to the variations of the exemplary configurations described above.

[0023]

[0028] In the illustrated example, the illumination light source 106 is a horizontally disposed solid-state illumination light source in the form of a light-emitting diode (LED) array consisting of a substrate 122 on the bottom surface of which a plurality of LEDs 124 are densely arranged. For example, the substrate 122 may be a printed circuit board (PCB) having traces for connecting the plurality of LEDs to a power supply and / or control circuit (not shown). For example, such a power supply and / or control circuit may include an on-demand (intermittent) energy source or switch for turning the illumination light source on and off, thereby providing a corresponding on-demand reaction in the photoreactor chamber 104. As another example, the illumination light source 106 may include a plurality of LED circuit boards adjacent to each other, and each LED board includes a plurality of LEDs, such as thousands of LEDs each having a width of about 1 to 5 mm, for example. In embodiments where the illumination light source 106 utilizes LEDs, the LEDs may be selected to emit photons, for example, in the ultraviolet to visible light spectrum (i.e., from about 200 nm to about 750 nm) or the visible light spectrum (i.e., from about 380 nm to about 750 nm). Alternatively or additionally, the illumination light source 106 may include a plurality of infrared (IR) lamps attached via a socket, connector, pin, wire, or other configuration to emit photons in the near-infrared spectrum (i.e., from about 750 nm to about 2,500 nm). Other exemplary embodiments may include illumination light sources that utilize other types of photon emitters, such as one or more ultraviolet (UV) lamps and voltaic arc lamps. Generally, to promote efficient photocatalysis, the illumination light source 106 is selected and / or controlled (e.g., via a control circuit on, on, or electrically coupled to the illumination light source 106, such as on the substrate 122) to emit photons having sufficient energy (i.e., peak irradiance (intensity) and energy density) and wavelength to activate the desired light-induced gas-phase reaction.

[0024]

[0029] To maximize the number of incident photons hitting the upper surface of the catalyst bed 118, the illumination source 106 preferably emits photons incident on substantially the entire upper surface of the window 108 and the photoreactor chamber 104. Thus, in an exemplary embodiment, the diameter or width of the active (photon-emitting) portion of the illumination source 106 is approximately the same as the diameter of the window 108 and the diameter of the layer 118 of the catalyst bed, or perhaps slightly narrower considering the emission angle (beam angle) of the photon emitter. Further, the diameter of the substrate 122 of the illumination source 106 is generally equal to the inner diameter of the body 102 (in the case of the internal press-fit configuration as shown) or the outer diameter of the body 102 (in the case of the stacked configuration). A plurality of photon emitters (e.g., LEDs 124) may be disposed substantially over the entire substrate 122, and each photon emitter is spaced from adjacent photon emitters (or the body 102 or other components) according to specified design requirements, such as those related to power or control considerations, or protection from damage from heat or photon emission from nearby adjacent photon emitters. In an exemplary embodiment utilizing LEDs, the illumination source 106 includes from about 20,000 to 125,000 individual LEDs, each LED having a width of about 1 to 5 mm and being mounted on a PCB substrate 122 having a diameter of about 91 cm. In other exemplary embodiments, different photon emitter densities may be possible and / or preferred, depending, for example, on design requirements, cooling systems, and / or power / control circuits.

[0025]

[0030] The illumination source 106 is selected and / or controlled to emit photons at a specific target wavelength or wavelength range (or specific plural target wavelengths or wavelength ranges) in the electromagnetic spectrum. Such target wavelength or wavelength range is selected to catalyze a desired chemical reaction by maximizing absorption in the layer 118 of the catalyst bed at that target wavelength or wavelength range. For example, the layer 118 of the catalyst bed may have a catalyst coupled to a plasmonic material (i.e., a plasmonic photocatalyst) having a plasmon resonance frequency corresponding to the selected target wavelength or wavelength range. Matching the plasmon resonance frequency to the target wavelength or wavelength range can be achieved, for example, by the design of the plasmonic photocatalyst, or the selection / control of a specific photon emitter, or both.

[0026]

[0031] The illumination light source 106 may optionally include a physically adjacent cooling block 126 (or a plurality of such cooling blocks 126), and the cooling block 126 may take the form of, for example, a heat sink (e.g., with cooling fins), a cooling fan, or a fluid cooling system. In the example shown, the cooling block 126 includes one or more cooling passages or chambers through which the coolant C can pass, as shown in a simplified schematic form by the dashed lines and arrows shown in FIG. 1A. As shown, the coolant C is introduced into the cooling block 126 via one or more coolant inlets 128 and removed (as the used coolant C') via one or more coolant outlets 130. In some exemplary embodiments, the coolant C is recirculated in a closed loop system through the cooling block 126 by a pump (not shown) after passing through a heat exchanger (not shown) to remove heat from the used coolant C'. In another exemplary embodiment, the used coolant C' is not recirculated through the cooling block 126 and is instead discarded or utilized elsewhere (e.g., for heating purposes in another related or unrelated process). In yet another exemplary embodiment, the coolant C circulated through the cooling block 126 may include a portion of the product gas P generated from the product gas outlet 114 via, for example, a dedicated cooling loop with a valve and an in-line chiller connected to the coolant inlet 128.

[0027]

[0032] In an embodiment where the illumination light source 106 utilizes a cooling block 126 as shown in FIG. 1A, the coolant C may be selected, for example, from the following non-exhaustive list: water, ammonia, synthetic hydrocarbons of aromatic chemistry (i.e., diethylbenzene [DEB], dibenzyltoluene, diarylalkyl, partially hydrogenated terphenyl), silicate esters, paraffinic and isoparaffinic aliphatic hydrocarbons, dimethyl and methylphenyl poly(siloxane), perfluorocarbons (i.e., FC-72, FC-77) fluorinated compounds such as hydrofluoroethers (HFE), and perfluorocarbon ethers (PFE), ethylene glycol, propylene glycol, methanol / water, ethanol / water, calcium chloride solution (e.g., 29 wt%), aqueous solutions of potassium formate and acetate salts, and liquid metals (e.g., Ga-In-Sn). Generally, the coolant C is selected to have a predetermined heat capacity that meets the desired cooling requirements, such as those specified for the photon emitter used in the illumination light source 106.

[0028]

[0033] In the exemplary embodiment shown, the optically transparent window 108 is a cylindrical disk adjacent to the illumination source 106, positioned between the light source 106 and the chamber section 116 of the photoreactor chamber 104. Although shown as a single component having a flat monolithic structure that functions as a simple optical window, the window 108 may include a plurality of physical components, and either or both of the upper and lower surfaces of the window 108 may be slightly curved so as to function as a lens (e.g., to control the angle of light transmission from the illumination source 106 to the layer 118 of the catalyst bed). The optical transparency of the window 108 is related to the wavelength or wavelength range of the photons emitted by the illumination source 106, such that light passes from the illumination source 106 through the window 108 into the photoreactor chamber 104 without significant scattering. In other words, the photons emitted by the illumination source 108 generally follow Snell's law when passing through the window 108. As a result, the photons emitted by the illumination source 106 can pass through the window 108 and the chamber section 116 (containing only the pressurized reaction gases from the reaction gas supply streams Ra and Rb) and strike the upper surface of the catalyst bed as incident photons. When utilizing the target wavelengths and wavelength ranges in the exemplary spectral ranges described herein, the window 108 is composed of glass, quartz, or other optically transparent materials such as sapphire or transparent ceramics in order to provide such optical transparency.

[0029]

[0034] The surface of the window 108 adjacent to the photoreactor chamber 104 functions as the ceiling (the uppermost gas-impermeable closed surface) of the photoreactor chamber 104. Therefore, the window 108 needs to have a thickness (e.g., a thickness of 1 cm or more such as 5 cm) or structure sufficient to withstand the pressure (plus tolerance) imposed by the reaction gas supply streams Ra and Rb flowing into the photoreactor chamber 104 through the respective reaction gas inlets 112a and 112b.

[0030]

[0035] Window 108 is adjacent to illumination light source 106, but according to an exemplary embodiment, window 108 is not in direct physical contact with the photon emitter (e.g., LED 124) of illumination light source 106. Instead, a gap 132 is provided in cylindrical body 102 over window 108 between window 108 and the photon emitter (e.g., LED 124) attached to substrate 122. The thickness of gap 132 may be defined by a thin circumferential spacer 134 composed of a metal or another heat-resistant, preferably reflective material having a coefficient of thermal expansion similar to that of body 102. Gap 132 may be filled with an optically transparent nonflammable gas such as air or nitrogen, or alternatively may be configured as a vacuum.

[0031]

[0036] As an alternative to the spacer ring 134, when included, the gap 132 may be defined by a ridge or protrusion (e.g., a circular circumferential ring-shaped protrusion in the case of the cylindrical photoreactor 101) extending from the surface of the substrate 122 of the light source 106 or the window 108 to provide a spacing between the window 108 and the photon emitter 124 of the light source 106. As yet another alternative, the wall of the cylindrical body 102 may extend upwardly beyond the upper surface of the window 108 (the window 108 being positioned within the body 102), thereby providing a circumferential lip (e.g., similar to the spacer ring 134 described above) on which the substrate 122 (or other portion of the light source 106) can be positioned to form the gap 132. Depending on the particular configuration of the photoreactor 100 (i.e., whether the components are housed within the body 102 or stacked on top of the cylindrical body 102), the spacer ring 134 may have an inner diameter (or other length / width dimension) equal to the inner diameter of the body 102 (in the case of a stacked configuration) or an outer diameter substantially equal to the inner diameter of the body 102 (in the case of an internal press-fit configuration). To maximize the number of incident photons hitting the upper surface of the catalyst bed layer 118, a plurality of photon emitters (e.g., LEDs 123) of the illumination light source 106 preferably emit photons over substantially the entire surface area above the window 108 (assuming the window 108 does not have a curvature that acts as a lens) and within the photoreactor chamber 104. This can be achieved by minimizing the thickness of the spacer ring 134 (in the case of an internal press-fit configuration) or configuring the ring to have an inner diameter equal to the inner diameter of the body 102 (in the case of a stacked configuration) so as not to impede light transmission.

[0032]

[0037] Returning to the exemplary embodiment of FIG. 1A, reaction gas supply streams Ra and Rb may be provided as a continuous flow of one or more pressurized reaction gases into chamber section 116 of photoreactor chamber 104, respectively, via respective reaction gas inlets 112a and 112b (within one or more vertical sidewalls of body 102). Although two reaction gas inlets 112a and 112b are shown, other exemplary embodiments may include three or four (or more) reaction gas inlets, or a single reaction gas inlet, each with a respective reaction gas supply stream providing a continuous flow of pressurized reaction gas. The number of reaction gas inlets may depend, for example, on the number of different reaction gases to be reacted, the size of reactor body 102 (e.g., a larger body 102 may require more reaction gas inlets), and / or the desired reaction gas pressure within the chamber section.

[0033]

[0038] The reaction gas supply stream Ra may contain the same or different process gas(es) as that contained in the reaction gas supply stream Rb. For example, when the photoreactor 100 is used for ammonia (NH3) synthesis, the reaction gas supply stream Ra may mainly contain nitrogen (N2) as the first process gas, and the reaction gas supply stream Rb may mainly contain hydrogen (H2) as the second process gas. Next, the two streams Ra and Rb are mixed within the chamber compartment 116, and nitrogen (N2) and hydrogen (H2) react when the mixed process gas flows through the layer 118 of the catalyst bed while being irradiated by the illumination light source 106, and ammonia (NH3) is produced as the product gas. In an alternative photoreactor 101 for ammonia synthesis, the reaction gas supply stream Ra and the reaction gas supply stream Rb may each contain a controlled mixture of nitrogen (N2) process gas and hydrogen (H2) process gas so as to be synthesized into ammonia (NH3) product gas within the photoreactor chamber 104. As another example, the reaction gas supply streams Ra and Rb each mainly contain ethane (C2H6) as the process gas, which reacts within the photoreactor chamber 104 by a photocatalytic selective partial dehydrogenation process to produce ethylene (C2H4) as the product gas P. As yet another example, the reaction gas supply streams Ra and Rb each mainly contain propane (C3H8) as the process gas, which reacts within the photoreactor chamber 104 by a photocatalytic selective partial dehydrogenation process to produce propylene (C3H6) as the product gas P.

[0034]

[0039] During operation, the reactive gas supply streams Ra and Rb introduce a continuous stream (or multiple continuous streams) of process gas into the chamber compartment 116. The introduced process gas then vertically passes through the thin catalyst bed layer 118 from the top surface to the bottom surface and flows as product gas P through the gas permeable plate 120 into the product gas compartment 110. The product gas P is output as a continuous stream (during operation) through the product gas outlet 114. As described above with respect to the cooling block 126, for some product gas (e.g., ammonia (NH3)), a portion of the stream of product gas P output from the product gas outlet 114 may be utilized as the coolant C (or its components) in the cooling block 126.

[0035]

[0040] The catalyst bed layer 118 is a photocatalyst packed bed (or a "fixed bed" rather than a "fluidized bed") having a photocatalyst on a carrier material. For example, the catalyst bed layer 118 may include a photocatalyst co-precipitated with the carrier material. The photocatalyst may include, for example, antennal reactor plasmonic nanoparticles. Various antennal reactor catalysts developed by Rice University are described in U.S. Patent No. 10,766,024, which is incorporated herein by reference, and can effectively utilize light energy to perform various chemical reactions. For example, such antennal reactor catalysts can be used in the exemplary photoreactor embodiments described herein to achieve a high conversion rate at a high space velocity and relatively high product gas production rate per unit volume of the catalyst bed. Depending on the type of chemical reaction being performed, an appropriate antennal reactor catalyst can be matched with a corresponding appropriate photon emitter (e.g., LED 124) to efficiently activate the photocatalyst, and as a result, a relatively high reaction rate can be achieved compared to conventional plasmonic or non-plasmonic photocatalysts.

[0036]

[0041] In an exemplary embodiment, the carrier material within the catalyst bed layer 118 exhibits relative optical transparency at the wavelength or wavelength range targeted by the desired chemical reaction (absorption or scattering is reduced compared to an opaque material), thereby facilitating light transmission over a longer distance within the catalyst bed layer 118. In some exemplary embodiments, the carrier material includes silica, quartz, fused quartz, glass, borosilicate glass, aluminosilicate glass, lithium aluminosilicate glass, sapphire, diamond, transparent aluminum oxide (such as α-phase aluminum oxide or γ-phase aluminum oxide), cesium oxide, magnesium oxide, or iron oxide, and is in the form of powder, alloy, beads, microporous beads, fibers, spheres, pellets, cylinders (hollow or otherwise), honeycombs, or symmetric or asymmetric three-lobe or four-lobe (e.g., by extrusion or tableting) forms.

[0037]

[0042] In an exemplary embodiment, the catalyst bed layer 118 is formed by filling a photocatalytic material (photocatalyst and carrier material) onto a gas-permeable plate 120 that supports the catalyst bed layer 118 and prevents the photocatalyst and / or its carrier material within the catalyst bed layer 118 from falling toward the product gas compartment 110. The gas-permeable plate 120 may be a perforated plate. The gas-permeable plate 120 may be composed of a metal grid that is electrically heated to enhance the catalytic performance for a specific chemical reaction, or may include a metal grid.

[0038]

[0043] To maintain the gas-permeable plate 120 at a fixed position within the main body 102 of the photoreactor 100, a circumferential spacer ring 136 (e.g., composed of metal or other material) may be provided with a height equal to the desired height of the product gas chamber 110 within the main body 102 and an outer diameter approximately equal to the inner diameter of the main body 102. Other positioning techniques may also be utilized for the gas-permeable plate 120, such as static friction (press-fit) forces or those that utilize ridges incorporated into the inner wall of the main body 102.

[0039]

[0044] In an exemplary embodiment, the catalytic bed layer 118 is cylindrical (or generally conforms to the shape type of the main body 102) and extends horizontally across the entire inner diameter of the main body 102 of the photoreactor 100. Further, the catalytic bed layer 118 is relatively thin in terms of its diameter / length·width (height), and in an exemplary embodiment, it has a thickness of 1 cm or 2 cm or 3 cm or a thickness between 1 cm and 3 cm including the boundaries, or a thickness greater than 1 cm, or a thickness less than 3 cm. According to an exemplary embodiment, the catalytic bed layer 118 has a thickness-to-radius ratio of less than 1.0. The thickness of the catalytic bed layer 118 may be optimized for the space velocity (gas supply rate) for a specific chemical reaction.

[0040]

[0045] The relatively thin photocatalytic bed of the catalytic bed layer 120 provides technical advantages. One such advantage is a reduction in the pressure drop across the catalytic bed layer 120. Further, as described in the following paragraphs, the relatively thin photocatalytic bed may further enable the control of industrially relevant and impactful chemical reactions.

[0041]

[0046] Due to the strong interaction between light and matter, the penetration depth of photons into optically active metal catalysts is typically limited to several hundred microns. Strong photon absorption results in strongly heating the catalyst and generating local heat zones (hot spots) on the upper surface of the catalyst under irradiation. As a result, a large vertical temperature gradient occurs across the depth of the catalyst bed and in the direction of the gas flow, with the bottom side of the catalyst being at a much lower temperature. See, e.g., Robatjazi, H., Zhao, H., Swearer, D. F. et al. Plasmon-induced selective carbon dioxide conversion on earth-abundant aluminum-cuprous oxide antenna-reactor nanoparticles. Nat Commun 8, 27 (2017). https: / / doi.org / 10.1038 / s41467-017-00055-z (which is hereby incorporated by reference in its entirety for all purposes). Such temperature gradients can be uniquely utilized, along with other photon-assisted bond activation mechanisms (e.g., non-thermal or electronic effects), to enable many industrially relevant chemical reactions to proceed under light irradiation. These photocatalytic reactions exhibit efficiencies that exceed those controlled by the thermal equilibrium in conventional thermocatalytic reactions in thermal power plants, for example, to drive reactions that are plagued by competing kinetic and thermodynamic demands. One example is the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2). In this reaction, the strong heating of the catalyst on the upper surface of layer 118 of the catalyst bed under irradiation forms a desirable "high-temperature catalyst zone" for the dissociation of N2 with a large activation barrier. In contrast, the "low-temperature catalyst zone" near the bottom of layer 118 of the catalyst bed, on the side opposite the illumination layer 106, promotes the formation of N-H bonds and the desorption of NH3, which would otherwise readily decompose back to its components at high catalyst bed temperatures (i.e., in the case of conventional thermocatalysts). Thus, the photoinduced temperature gradient may effectively enable low-temperature ammonia synthesis with an efficiency that exceeds that defined by the thermodynamic equilibrium in a thermal plant with a uniform catalyst bed temperature by using only light as the energy input to the photoreactor chamber.Based on the magnitude of the temperature gradient, by utilizing a relatively shallow catalyst bed depth, it is possible to maximize the effective volume-to-mass ratio of the catalyst contributing to the photocatalytic reaction. Furthermore, due to the short residence time of the gas within the thin catalyst layer, the possibility of ammonia decomposition due to the reverse reaction can also be minimized. Another potential application of such a photoreactor design having a relatively thin catalyst bed layer is in partial dehydrogenation processes, such as when improving the selectivity of ethylene to acetylene in the photocatalytic dehydrogenation of ethane.

[0042]

[0047] To assist in measuring the above-described temperature gradient between the top and bottom surfaces of the catalyst bed layer 118, an exemplary embodiment of the photoreactor 100 may further optionally include two (or more) thermocouples 138 and 140 at two (or more) respective optional through-type inlets within the body 102 for measuring the temperature of the respective top and bottom surfaces of the catalyst within the catalyst bed layer 118. In another exemplary embodiment, intermediate temperatures can be measured via one or more additional intermediate thermocouples within the catalyst bed layer 118.

[0043]

[0048] In an alternative embodiment, an embedded heating unit (not shown), such as an embedded coil or grid heater, or a plurality of embedded IR lamps, can be provided within the catalyst bed layer 118 to provide heat for a specific chemical reaction. In such an embodiment, the catalyst bed layer 118 can be made thicker than in the above examples to accommodate the embedded heating unit and / or to create a predetermined temperature difference across the fixed catalyst bed.

[0044]

[0049] As an exemplary design embodiment of the photoreactor 100 shown in FIG. 1A, the photoreactor 100 can be a cylindrical photoreactor comprising a layer 118 of catalyst bed having a diameter of 91 cm and a corresponding LED module having an effective diameter of 84.4 cm (i.e., of a photon emitter such as the LED 124). This LED module can contain, for example, from 20,000 to 125,000 individual LEDs. Assuming a photon energy transfer efficiency of 90% from the surface of the LED module to the surface of the catalyst bed layer 118, in this exemplary design, a maximum of 40 W / cm 2 (at the surface of the catalyst bed layer 118) of incident light intensity can be achieved.

[0045] III. Experimental Data

[0050] FIG. 2 is a graph 200 showing experimental data of photocatalytic ammonia synthesis using a photoreactor design corresponding to the photoreactor 100 of FIG. 1A. In particular, FIG. 2 shows the ammonia production yield at a pressure of 3 atm as a function of temperature (see below) compared to the thermal equilibrium limit by Haber and le Rossignol. See Smil, V., Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of the World Food Production, MIT Press, Cambridge, MA, 2001. The graph 200 of FIG. 2 includes an upper part 210 showing the production of ammonia as a function of increasing irradiation power (the measured bulk temperature correspondingly increases due to photoinduced heating) and a lower part 220 showing real-time monitoring data of the concentration (ppm) of the synthesized ammonia. The upper part 210 includes a 3 atm ammonia synthesis thermodynamics equilibrium curve 230 obtained from the "Thermodynamic Equilibrium of Ammonia Synthesis" graph shown in FIG. 3 by Haber in 1920.

[0046]

[0051] Photocatalytic ammonia synthesis was carried out by: (a) a process gas provided at a pressure of 3 atm within chamber section 104, (b) an illumination light source 106 that emits light in the visible spectrum, (c) a layer of catalyst bed containing 4 grams of catalyst, and (d) a measured bulk temperature up to about 465 °C. The apparent temperature related to photocatalysis (x-axis of the upper part 210 of FIG. 200) refers to the measured bulk temperature due to photoinduced heating of the catalyst under various irradiation powers (see the diagonal "Irradiation power increase" trend line indicating the increase in ammonia production corresponding to the increase in irradiation) where no additional external heating is applied in photocatalysis.

[0047]

[0052] As shown in the upper part 210 of FIG. 200, ammonia was synthesized up to about 14,000 ppm, which is more than about 100% above the heat equilibrium limit in ammonia synthesis on the 3 atm thermodynamic equilibrium curve 230 (see the star mark "Heat equilibrium limit" in the upper part 210 of FIG. 200). The experimentally observed photocatalytic reaction rate is significantly higher than the rate achievable with conventional thermal processes at a given pressure and temperature. This result indicates that the technology described herein has the potential to achieve a conversion rate exceeding that of the conventional Haber - Bosch process (15%) under milder operating conditions (lower pressure and temperature). The experimental results presented here are related to specific process gas pressure, light wavelength, irradiation power, catalyst amount / concentration, and measured photoinduced heating, but other experimental setups that yield beneficial results are also conceivable, such as when synthesizing ammonia at a rate / amount exceeding the limit of heat equilibrium.

[0048]

[0053] The lower part 220 of FIG. 200 in FIG. 2 shows the real-time monitoring of the concentration (ppm) of synthesized ammonia in a specific irradiation and the corresponding measured bulk temperature due to photoinduced heating of the catalyst. As shown, (a) the generation of ammonia starts almost immediately in response to the power-on of the illumination light source (the sharp rising slope starts at "LED on"), (b) the generation of ammonia approaches a steady state within several tens of minutes after the power-on of the illumination light source (the slope becomes flat and approaches 4000+ppm), and (c) in response to the power-off of the illumination light source, the generation of ammonia stops within several tens of minutes (the sharp descending slope starts at "LED off"). The almost immediate response of the system to the on / off of illumination enables the use of an intermittent (e.g., switchable) energy source for wide-ranging distributed on-demand ammonia generation.

[0049] IV. Exemplary Embodiments

[0054] The following are exemplary embodiments of the technology described in this specification.

[0050]

[0055] Example 1. A photoreactor, a. A photoreactor body including a vertical length having an upper end and a lower end, b. An inlet disposed on the sidewall of the photoreactor body between the upper end and the lower end, the inlet for receiving a continuous flow supply stream of a process gas, c. An outlet disposed at the lower end of the photoreactor body for discharging a product gas stream, d. A gas-permeable plate disposed inside the photoreactor body below the inlet and above the outlet, e. A product gas compartment inside the photoreactor body defined by a space between the perforated plate and the lower end of the photoreactor body, f. A catalyst fixed bed disposed as a layer of a catalyst bed inside the photoreactor body adjacent to the perforated plate and on the opposite side of the product gas compartment, g. An optically transparent window disposed at the upper end of the photoreactor body, h. A chamber compartment inside the photoreactor body defined by the space between the catalyst fixed bed and the optically transparent window, the chamber compartment having an inlet that provides a continuous flow supply stream of process gas to the chamber compartment, and i. An illumination light source having a plurality of photon emitters positioned adjacent to but not in contact with the optically transparent window, the illumination light source emitting photons onto the upper surface of the catalyst fixed bed through the optically transparent window and the chamber compartment, thereby catalyzing a chemical reaction involving the process gas to produce a product gas stream output through the outlet, and A photoreactor comprising.

[0051]

[0056] Example 2. The photoreactor of Example 1, wherein the photoreactor body is cylindrical.

[0052]

[0057] Example 3. The photoreactor of any of the preceding examples, wherein the illumination light source is an LED module and the plurality of photon emitters are a plurality of LEDs on the substrate of the LED module.

[0053]

[0058] Example 4. The photoreactor of any of the preceding examples, further comprising a cooling block adjacent to the illumination light source.

[0054]

[0059] Example 5. The photoreactor of Example 4, wherein the cooling block includes a fluid inlet for introducing a coolant into the cooling block and a fluid outlet for removing the coolant from the cooling block after the coolant has circulated through a portion of the cooling block.

[0055]

[0060] Example 6. The photoreactor of any of the preceding examples, wherein the photoreactor body is made of a high-pressure resistant material.

[0056]

[0061] Example 7. The photoreactor of Example 6, wherein the photoreactor body is evaluated at a pressure of at least 4 standard atmospheres (405.3 kPa).

[0057]

[0062] Example 8. The photoreactor of any of the preceding examples, wherein the photoreactor body is made of a structural alloy of steel or nickel, titanium, aluminum, or quartz.

[0058]

[0063] Example 9. A photoreactor according to any of the preceding examples, wherein the optically transparent window is a disk made of quartz, sapphire, a transparent ceramic, or glass.

[0059]

[0064] Example 10. A photoreactor according to any of the preceding examples, wherein the optically transparent window has a thickness of at least 1 cm.

[0060]

[0065] Example 11. A photoreactor according to any of the preceding examples, wherein the inlet comprises a plurality of inlets.

[0061]

[0066] Example 12. A photoreactor according to any of the preceding examples, wherein the catalyst fixed bed is supported by a gas-permeable plate, and the gas-permeable plate prevents catalyst particles from the catalyst fixed bed from falling into the product gas compartment.

[0062]

[0067] Example 13. A photoreactor according to any of the preceding examples, wherein the catalyst fixed bed has a thickness between 5 mm and 5 cm.

[0063]

[0068] Example 14. A photoreactor according to any of the preceding examples, wherein the catalyst fixed bed has a thickness smaller than the width of the catalyst fixed bed disposed on the gas-permeable plate within the photoreactor body.

[0064]

[0069] Example 15. A photoreactor according to any of the preceding examples, wherein the illumination light source has a width substantially the same as the width of the photoreactor body, thereby irradiating substantially the entire width of the photoreactor body within the chamber compartment and the upper surface of the catalyst fixed bed.

[0065]

[0070] Example 16. A photoreactor according to any of the preceding examples, wherein the illumination light source is separated from the optically transparent window by at least one of (a) a metal ring having a width substantially the same as the width of the photoreactor body, or (b) an extended wall portion of the photoreactor body extending between the optically transparent window and the illumination light source.

[0066]

[0071] Example 17. A photoreactor according to any of the preceding examples, wherein the compartment defined by the space between the optically transparent window and the illumination light source is filled with at least one of (a) air, (b) a gas, or (c) a vacuum.

[0067]

[0072] Example 18. a. A first thermocouple disposed above the catalyst fixed bed; and b. Further comprising a second thermocouple disposed below the fixed bed, c. The first thermocouple and the second thermocouple provide respective first and second temperature measurements indicative of the temperature difference between the upper and lower portions of the catalyst fixed bed. A photoreactor according to any of the preceding examples.

[0068]

[0073] Example 19. A photoreactor according to Example 18, wherein the first and second thermocouples pass through respective through-type inlets disposed on the side wall of the photoreactor body.

[0069]

[0074] Example 20. During operation, a continuous flow supply stream of process gas continuously flows into the chamber compartment through the inlet, reacts as it passes through the catalyst fixed bed from top to bottom to become product gas, and the product gas flows into the product gas compartment through the perforated plate and is discharged from the outlet. A photoreactor according to any of the preceding examples.

[0070]

[0075] Example 21. A photoreactor according to any of the preceding examples, wherein the illumination light source includes at least one of (a) an IR lamp or (b) an ARC lamp.

[0071]

[0076] Example 22. A photoreactor according to any of the preceding examples, wherein the gas-permeable plate includes a heated metal grid.

[0072]

[0077] Example 23. A photoreactor according to Example 22, wherein the heated metal grid is heated using electricity to enhance the catalyst performance.

[0073]

[0078] Example 24. A photoreactor according to any of the preceding examples, wherein the catalyst fixed bed includes at least one heating element disposed therein.

[0074]

[0079] Example 25. The photoreactor of Example 24, wherein at least one heating element comprises at least one of (a) an embedded electric heating unit or (b) an IR lamp.

[0075]

[0080] Example 26. The photoreactor of Example 24 or 25, wherein the catalyst fixed bed is made relatively thick to accommodate at least one heating element and to create a predetermined temperature difference across the catalyst fixed bed.

[0076]

[0081] Example 27. The photoreactor of Example 4 or 5, wherein the product gas contains ammonia and the coolant contains at least a portion of the product gas.

[0077]

[0082] Example 28. The photoreactor of any of the preceding examples, wherein the process gas mainly comprises nitrogen (N2) and hydrogen (H2), and the product gas comprises ammonia (NH3).

[0078]

[0083] Example 29. The photoreactor of Example 28, wherein ammonia is synthesized up to about 14,000 ppm through the photoreactor when (a) the process gas is provided at a pressure of 3 atm in the chamber compartment, (b) the illumination light source emits light in the visible spectrum, (c) the catalyst fixed bed contains 4 grams of catalyst, and (d) the measured bulk temperature due to photoinduced heating of the catalyst fixed bed is up to about 465°C.

[0079]

[0084] Example 30. The photoreactor of Example 28, wherein ammonia production starts almost immediately in response to turning on the power of the illumination light source, the ammonia production approaches a steady state within several tens of minutes after turning on the power of the illumination light source, and the ammonia production stops within several tens of minutes in response to turning off the power of the illumination light source.

[0080]

[0085] Example 31. The photoreactor of any of Examples 28 - 30, further comprising an intermittent on - demand energy source for turning on and off the power of the illumination light source, thereby providing corresponding on - demand ammonia production.

[0081]

[0086] Example 32. Any photoreactor of Examples 1-26, wherein the process gas mainly comprises ethane and the product gas comprises ethylene produced via a photocatalytic selective partial dehydrogenation process.

[0082]

[0087] Example 33. Any photoreactor of Examples 1-26, wherein the process gas mainly comprises propane and the product gas comprises propylene produced via a photocatalytic selective partial dehydrogenation process.

[0083] V. Conclusion

[0088] In the foregoing detailed description, various features and operations of the disclosed systems, apparatuses, devices, and / or methods have been described with reference to the accompanying drawings. The exemplary embodiments described herein and in the figures are not intended to be limiting, and the true scope is indicated by the following claims. As will be apparent to those skilled in the art, many modifications and variations are possible without departing from that scope. For systems, apparatuses, devices, and / or methods that are functionally equivalent within the scope of the present disclosure, in addition to those described herein, they will be apparent to those skilled in the art from the foregoing description. It will be readily understood that aspects of the present disclosure can be arranged, substituted, combined, separated, and designed in various different configurations as outlined herein and shown in the figures. Such modifications and variations are intended to be included within the scope of the appended claims. Finally, all publications, patents, and patent applications cited herein are hereby incorporated by reference for all purposes.

Claims

1. A photoreactor, comprising a photoreactor body having an upper end and a lower end, an inlet disposed on a sidewall of the photoreactor body between the upper end and the lower end, the inlet for receiving a continuous flow supply stream of process gas during operation, an outlet disposed at the lower end of the photoreactor body for discharging a product gas stream, a gas-permeable plate disposed inside the photoreactor body below the inlet and above the outlet, a product gas compartment inside the photoreactor body defined by a space between the perforated plate and the lower end of the photoreactor body, a catalyst fixed bed disposed as a layer of catalyst bed inside the photoreactor body adjacent to the perforated plate and on the opposite side of the product gas compartment, an optically transparent window disposed above the inlet, a chamber compartment inside the photoreactor body defined by a space between the catalyst fixed bed and the optically transparent window, the chamber compartment during operation receiving the continuous flow supply stream of process gas from the inlet, an illumination light source positioned adjacent to but not in contact with the optically transparent window, the illumination light source emitting photons onto an upper surface of the catalyst fixed bed through the optically transparent window and the chamber compartment, thereby catalyzing a chemical reaction involving the process gas to produce the product gas stream output through the outlet, and a photoreactor comprising the same.

2. The photoreactor according to claim 1, wherein the photoreactor body is cylindrical.

3. The photoreactor according to claim 1, wherein the illumination light source is an LED module including a substrate having a plurality of LEDs thereon.

4. The photoreactor according to claim 1, further comprising a cooling block adjacent to the illumination light source.

5. The photoreactor according to claim 4, wherein the cooling block includes a fluid inlet for introducing a coolant into the cooling block and a fluid outlet for removing the coolant from the cooling block after the coolant has circulated through a part of the cooling block.

6. The photoreactor according to claim 5, wherein the product gas contains ammonia and the coolant contains at least a part of the product gas.

7. The photoreactor according to claim 1, further comprising a cooling block adjacent to the illumination light source, the cooling block including a fluid inlet for introducing a coolant into the cooling block and a fluid outlet for removing the coolant from the cooling block after the coolant has circulated through a part of the cooling block.

8. The photoreactor according to claim 1, wherein the photoreactor body is evaluated at a pressure of at least 4 standard atmospheres (405.3 kPa).

9. The photoreactor according to claim 1, wherein the photoreactor body is made of a structural alloy of steel or nickel, titanium, aluminum, or quartz.

10. The photoreactor according to claim 1, wherein the optically transparent window is made of quartz, sapphire, transparent ceramic, or glass.

11. The photoreactor according to claim 1, wherein the optically transparent window has a thickness of at least 1 cm.

12. The photoreactor according to claim 1, wherein the inlet includes a plurality of inlets.

13. The photoreactor according to claim 1, wherein the catalyst fixed bed is supported by the gas permeable plate, and the gas permeable plate prevents catalyst particles from the catalyst fixed bed from falling into the product gas compartment.

14. The photoreactor according to claim 1, wherein the catalyst fixed bed has a thickness between 5 mm and 5 cm.

15. The photoreactor according to claim 1, wherein the catalyst fixed bed has a thickness smaller than the width of the catalyst fixed bed disposed on the gas permeable plate within the photoreactor main body.

16. The photoreactor according to claim 1, wherein the illumination light source has a width substantially the same as the width of the photoreactor main body, thereby irradiating substantially the entire width of the photoreactor main body within the chamber compartment and the upper surface of the catalyst fixed bed.

17. A first thermocouple disposed above the catalyst fixed bed; and A second thermocouple disposed below the fixed bed further comprising, wherein the first thermocouple and the second thermocouple provide respective first and second temperature measurement values indicating a temperature difference between the upper and lower portions of the catalyst fixed bed. The photoreactor according to claim 1.

18. The photoreactor according to claim 17, wherein the first and second thermocouples pass through respective through-type inlets disposed on the side wall of the photoreactor main body.

19. During operation, the continuous flow supply stream of the process gas continuously flows into the chamber compartment through the inlet, reacts when passing through the catalyst fixed bed from top to bottom to become a product gas, and the product gas flows into the product gas compartment through the perforated plate and is discharged from the outlet. The photoreactor according to claim 1.

20. The photoreactor according to claim 1, wherein the illumination light source includes at least one of (a) an IR lamp or (b) an ARC lamp.

21. The photoreactor according to claim 1, wherein the gas permeable plate includes a heated metal grid to enhance catalyst performance.

22. The photoreactor according to claim 1, wherein the catalyst fixed bed includes at least one heating element disposed therein.

23. The process gas is mainly nitrogen (N ２ ), and hydrogen (H ２ ), and the product gas contains ammonia (NH ３ ), the photoreactor according to claim 1.

24. The process gas mainly contains ethane, and the product gas contains ethylene produced through a photocatalytic selective partial dehydrogenation process, the photoreactor according to any one of claims 1.

25. The process gas mainly contains propane, and the product gas contains propylene produced through a photocatalytic selective partial dehydrogenation process, the photoreactor according to any one of claims 1.

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