Droplet type catalyst and heterogeneous catalysis method and application thereof

Abstract

The invention relates to the technical field of heterogeneous catalysis, discloses a heterogeneous catalysis method, and further discloses a liquid drop type catalyst and application thereof. According to the heterogeneous catalysis method, under reaction conditions, the catalyst and reactants are subjected to an interface contact catalytic reaction in a liquid drop form, and the particle size of the liquid drops is 1 nm-0. 1 mm. According to the heterogeneous catalytic reaction, the catalyst and reactants are subjected to interface contact catalytic reaction in a liquid drop form, so that the catalytic efficiency is improved, and the heterogeneous catalytic reaction using the liquid catalyst is realized. The liquid drop type catalyst provided by the invention is high in activity and controllable in reaction condition, so that large-scale preparation can be realized. The liquid drop type catalyst is high in activity, good in catalytic stability and wide in application.

Description

Technical Field

[0001] The present invention relates to the field of catalyst technology, in particular to a multiphase catalytic method in which a catalyst in the form of droplets contacts the interface of reactants for reaction, a droplet-type catalyst and applications thereof. Background Art

[0002] Liquid catalysts are mostly used for homogeneous catalytic reactions, while solid catalysts are used in most heterogeneous catalysis. In solid catalysts, the atoms on the solid surface have clear positions, they vibrate with small amplitudes around them, the surface has periodicity, and the active sites for dissociative adsorption are few and fixed. The inventors of this application have recognized that when the surface is liquid, because the surface atoms are mobile and form many configurations with transient lifespans; in addition, liquid atoms have higher mobility and can undergo larger displacements to adapt to the bonding "needs" of dissociated fragments; therefore, liquid catalysts have more active sites, and unlike solid catalysts that are rapidly deactivated due to factors including carbon deposition (coking), liquids provide a constantly updated gas-liquid interface and an environment for continuous separation of by-products (such as solid carbon). However, when liquid catalysts are applied in heterogeneous catalysis using the bubbling method, their catalytic area is small (such as the size of bubbles is 0.1-1 cm, while solid catalysts can often achieve particles or micropores with a diameter of 10-100 nm), and their comprehensive activity is not strong, so they have not been applied on a large scale in industry.

[0003] In addition, single-atom catalysis is one of the research hotspots in the field of catalysis. Theoretically, the limit of supported catalyst dispersion is that the active material is evenly distributed on the carrier in the form of single atoms, which is the ideal state of supported catalysts. Single-atom catalysts refer to catalysts in which the active material component M exists on the carrier in the form of "isolated atoms" (no MM bond exists). Single-atom catalysts first greatly improve the utilization efficiency of metal atoms with the lowest metal loading; they can change the adsorption / desorption selectivity of the active component on the catalyst for different molecules, thereby accelerating the reaction kinetics; single-atom catalysts also have the characteristics of uniform and single active centers of homogeneous catalysts and stable and easy-to-separate structures of heterogeneous catalysts. At the same time, when the particles are dispersed to the atomic level, the sharply increased surface energy, quantum size effect, unsaturated coordination environment and metal-support interaction give single-atom catalysts superior catalytic performance. However, when metal particles are reduced to the single-atom level, the specific surface area increases dramatically, resulting in a sharp increase in the surface free energy of the metal. During preparation and reaction, agglomeration and coupling easily occur to form large clusters, which leads to the deactivation of the single-atom catalyst. At the same time, the cost of catalyst preparation and its loading on the substrate is still extremely high, and it is very difficult to increase the loading amount, which brings huge challenges to the single-atom catalysis method.

[0004] At present, the large-scale preparation of precious metal SACs is still a major constraint. Most of the synthetic strategies reported so far can only prepare products at the gram level or even the milligram level. For example, the wet chemical co-precipitation method and wet impregnation method are simple to operate and have strong universality, and have the development prospect of large-scale preparation, but the main challenge they face is the amplification effect: when the catalyst is prepared under laboratory conditions, the synthesis conditions can be precisely controlled to obtain metal catalysts with atomic dispersion properties. However, when the production is scaled up according to the synthesis ratio, there are always uneven mass transfer and heat transfer effects, which can easily cause local concentration unevenness, thereby leading to metal agglomeration. Others, such as mass separation soft landing technology, require ultra-high vacuum preparation conditions and are difficult to mass produce; atomic layer deposition ALD has high requirements for operating conditions and equipment; in addition, preparation methods including reverse Ostwald ripening, step-by-step reduction, and solid-phase melting are still in the theoretical research stage.

[0005] Therefore, it is a huge challenge to develop a highly active, heterogeneous, liquid catalyst that can be applied on a large scale and can be prepared reliably, environmentally friendly, and economically on a large scale. Summary of the Invention

[0006] According to one embodiment of the present invention, an object is to provide a heterogeneous catalytic method, a droplet-type catalyst, and its application, in which a catalyst in the form of droplets contacts the reactants at the interface. This method addresses the problems of using solid-state catalysts for heterogeneous catalytic reactions, such as a limited number of fixed active sites, low activity, and the inability to achieve large-scale industrial application. This object can be achieved through the following technical solutions.

[0007] According to one aspect of the present invention, the present invention provides a multiphase catalytic method in which a catalyst in the form of droplets undergoes an interfacial contact catalytic reaction with reactants. Under reaction conditions, the catalyst in the form of droplets undergoes an interfacial contact catalytic reaction with reactants, wherein the particle size of the droplets is 1 nm to 0.1 mm.

[0008] Optionally, the catalyst is in the form of droplets, which are droplets prepared by pre-preparing a liquid catalyst before the heterogeneous catalytic reaction.

[0009] Optionally, an atomizing device is used to atomize the liquid catalyst into droplets. Furthermore, the reactant is a gas or a liquid, and the liquid is immiscible with the liquid catalyst. Furthermore, when the reactant is a gas, the atomized droplets and the gaseous reactant are introduced into a reaction vessel to carry out a gas-liquid interfacial contact reaction; when the reactant is a liquid, the atomized droplets are introduced into a reaction vessel containing the liquid reactant to carry out a liquid-liquid interfacial contact reaction.

[0010] Optionally, the liquid catalyst placed in the reaction vessel is evaporated and condensed to form droplets by heating, evaporation and recondensation. Furthermore, the reactant is a gas, and after the liquid catalyst evaporates and condenses into droplets, the gaseous reactant is introduced into the area where the droplets are located, so that the gaseous reactant and the droplets undergo a gas-liquid interface contact reaction.

[0011] Optionally, the catalyst is in the form of droplets, which are droplets formed under the reaction conditions of a heterogeneous catalytic reaction; wherein the reactant is a gas, and the catalyst is in the form of droplets to undergo sufficient interfacial contact catalytic reaction with the gas reactant.

[0012] Optionally, the method for forming droplets under the reaction conditions of a heterogeneous catalytic reaction is to pre-load the material components of the catalyst on the surface of a solid carrier and introduce them into a reaction vessel in solid form. Under the reaction conditions, the material components on the surface of the solid carrier are heated and melted into droplets, so that the gas reactants flow through the carrier and fully contact the droplets on the carrier.

[0013] Optionally, the method for forming droplets under the reaction conditions of a heterogeneous catalytic reaction can also be to pre-prepare the catalyst into an ultrafine powder, spray the ultrafine powder into a reaction vessel, and heat the ultrafine powder under reaction conditions to form droplets, so that the droplets contact and react with the gaseous reactants simultaneously introduced into the reaction vessel.

[0014] Optionally, the reaction vessel is a fluidized bed reactor or a fixed bed reactor.

[0015] Furthermore, when it is a fluidized bed reactor, the catalyst reacts with the gaseous reactants in the fluidized bed in the form of droplets; when it is a fixed bed reactor, a solid carrier with catalyst material components loaded on its surface is pre-filled in the reactor. Under the reaction conditions, the material components on the surface of the solid carrier are heated and melted into droplets, and the gaseous reactants flow through the fixed bed to undergo a catalytic reaction.

[0016] Optionally, the reactant is a gas, and the method further comprises: collecting liquid droplets at the bottom of the reaction container and / or the powder after cooling, removing impurities to obtain a catalyst, and reusing the catalyst.

[0017] According to another aspect of the present invention, the present invention provides a droplet-type catalyst used in accordance with the heterogeneous catalytic method, wherein the droplet-type catalyst refers to a catalyst that undergoes interfacial contact catalytic reaction with reactants in the form of droplets during a heterogeneous catalytic reaction; and the catalyst is in a liquid state in which all material components dissolve in each other under the reaction conditions.

[0018] Furthermore, the chemical composition of the catalyst includes at least one element selected from transition metals, metals with p electrons in the outer layer, rare earth metals, alkali metals, alkaline earth metals, metallic aluminum, and non-metallic sulfur, selenium, and tellurium; the chemical composition is obtained from material components, and the material components are one or more of a mixture, a single substance, and an inorganic compound.

[0019] Optionally, the catalyst is a single-atom catalyst, whose chemical composition includes at least two metal elements selected from transition metals, metals with p electrons on the outer layer, rare earth metals, alkali metals, alkaline earth metals, and metallic aluminum; and at least one chemical component element exists in a transient quasi-ionic state in the liquid.

[0020] Furthermore, the quasi-ionic state of the single-atom catalyst is manifested by the presence of non-integer Bader charges for at least two elements. For liquid-phase single-atom catalysts with different chemical compositions but the same elements, or for liquid-phase single-atom catalysts with the same chemical composition but different contents, the smaller the absolute value of the Bader charge, the higher the catalytic activity. The Bader charge is obtained by subtracting the explicit electrons of the pseudopotential from the integrated electron density within the Bader volume when calculating the electronic properties of a molten alloy using quantum mechanics and ab initio molecular dynamics.

[0021] Furthermore, the quasi-ionic state of the single-atom catalyst also exhibits an anomalous characteristic of having a resistivity different from that of a solid alloy.

[0022] Furthermore, the catalytic efficiency per unit catalytic area of ​​the single-atom catalyst is higher than that of the non-single-atom alloy catalyst. 3 ~10 8 times.

[0023] Optionally, the single-atom catalyst is in a liquid state under the reaction conditions in which all material components dissolve in each other, which is achieved by: dissolving into a liquid state at room temperature before the reaction, heating and melting into a liquid state before the reaction, or heating and melting into a liquid state under the reaction conditions.

[0024] Optionally, the catalyst is used for catalysis by direct interface contact with reactants without adding other reagents.

[0025] Optionally, the transition metal includes titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, niobium, molybdenum, ruthenium, silver, cadmium, tungsten, rhenium, platinum, gold, and mercury; the metal with p electrons in the outer layer includes gallium, indium, tin, antimony, lead, and bismuth; the rare earth metal includes lanthanum, cerium, praseodymium, neodymium, samarium, and europium; the alkali metal includes lithium, sodium, potassium, rubidium, cesium, and francium; and the alkaline earth metal includes magnesium and calcium.

[0026] Optionally, the liquid-phase single-atom catalyst has a chemical composition of at least two elements selected from metal gallium, indium, tin, antimony, lead, and bismuth whose outer shells are p electrons.

[0027] Optionally, the liquid-phase single-atom catalyst comprises a first element and a second element. The second element is at least one element selected from the group consisting of p-electron metals such as gallium, indium, tin, antimony, lead, bismuth, and rare earth metals such as lanthanum, cerium, and samarium. The first element is at least one element selected from the group consisting of transition metals such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, silver, platinum, and gold; alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as magnesium and calcium; and aluminum. Furthermore, the second element preferably comprises no less than 35% of the total catalyst.

[0028] Optionally, the first element is at least two selected from the group consisting of transition metals titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, silver, platinum, and gold; alkali metals lithium, sodium, and potassium; alkaline earth metals magnesium and calcium; and aluminum. Furthermore, the first element includes at least manganese.

[0029] Optionally, the first element is selected from transition metals manganese, nickel, platinum, iron, silver, and ruthenium. Further, the first element includes at least metal manganese.

[0030] Optionally, the material component is one or more of a halide, a hydroxide, and an oxygen-containing acid, and the melting point of the material component is lower than 1300°C.

[0031] According to another aspect of the present invention, the application of the droplet-type catalyst provided by the present invention is applied to any reaction process of dehydrogenation reaction, hydrogenation reaction, olefin hydroformylation reaction, ammonia-related reaction, petroleum refining catalytic reaction, biomass catalytic utilization, organic pollutant treatment and polymer material regeneration.

[0032] Furthermore, the hydrogenation reaction includes: olefin hydrogenation and acetylene hydrogenation.

[0033] Furthermore, when the liquid-phase single-atom catalyst is used in a dehydrogenation reaction, the dehydrogenation reaction can be any one of methane thermal cracking, methane dry reforming, methane steam reforming, methane coupling to ethylene, methane oxygen-free coupling to aromatics, ethane dehydrogenation / oxidative dehydrogenation, propane dehydrogenation / oxidative dehydrogenation, C4 and above alkane dehydrogenation and oxidative dehydrogenation, ethylbenzene dehydrogenation, butane carbon dioxide coupling to light aromatics, and thermal cracking reactions of aromatic hydrocarbons, polyolefins, and asphalt.

[0034] Furthermore, when the liquid-phase single-atom catalyst is used in an ammonia-related reaction, the ammonia-related reaction is any one of ammonia decomposition, ammonia synthesis, ammonia oxidation, aniline production from nitrobenzene, and SCR denitration reaction.

[0035] Beneficial Effects: According to a heterogeneous catalytic reaction provided by one embodiment of the present invention, the catalyst, in the form of droplets of a specific particle size, undergoes interfacial contact catalytic reaction with the reactants, improving catalytic efficiency and enabling heterogeneous catalytic reactions using liquid catalysts. The droplet-type catalyst provided by one embodiment of the present invention has high activity, controllable reaction conditions, scalable preparation, good catalytic stability, and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of three atomizing devices (nozzles) for forming droplets in the heterogeneous catalytic reaction of the present invention.

[0037] Figure 2 Schematic diagram of the structure of the device used in the heterogeneous catalytic reaction of Example 1 of the present invention.

[0038] Figure 3 Schematic diagram of the structure of the device used in the heterogeneous catalytic reaction of Example 5 of the present invention.

[0039] Figure 4 1 is a schematic diagram of the process of the reaction between the atomized droplet catalyst and the liquid reactant in one embodiment of the present invention.

[0040] Figure 5 1 is a schematic diagram of the process of the reaction between the atomized liquid droplet catalyst and the gaseous reactant in one embodiment of the present invention.

[0041] Figure 6 It is a schematic diagram of the process of the reaction between the catalyst evaporated and condensed into liquid droplets and the gaseous reactants in one embodiment of the present invention.

[0042] Figure 7 The figure is a schematic flow diagram of a process in which a catalyst component supported on a carrier is heated and melted into liquid droplets under reaction conditions and reacts with a gaseous reactant in one embodiment of the present invention.

[0043] Figure 8 The present invention is a schematic flow chart of an embodiment of the present invention in which a catalyst is pre-prepared into ultrafine powder and formed into liquid droplets under reaction conditions and reacted with gaseous reactants. DETAILED DESCRIPTION

[0044] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] As mentioned above, the existing catalysts used for heterogeneous catalysis are usually solid catalysts. The inventors of the present application have realized that when a solid catalyst is used for a heterogeneous catalytic reaction, there are problems such as a small number of active sites and that they are fixed, the activity is not high, and large-scale industrial applications cannot be obtained. Based on this, the present application provides a heterogeneous catalytic method, in which the catalyst is in the form of droplets and the reactants undergo interfacial contact catalytic reaction under reaction conditions. On the one hand, the catalyst is in liquid form for catalysis, and the liquid state allows the catalyst to have more active sites; on the other hand, the particle size of the droplets is 1nm to 0.1mm, and the particle size of the droplets gives the catalyst a huge specific surface area, which increases the effective catalytic area, and the time with the reactants in the reaction system is effectively controllable, and the catalytic reaction time is stable and controllable. In addition, the inventors of the present application have noticed that compared with the gas reactant being blown into the catalyst of the continuous liquid phase in the form of bubbles (the scale of the bubble blown out can be controlled in the range of 0.1cm-1cm), the droplets (catalyst) have a huge specific surface area, and the effective catalytic area per unit is greatly improved, which is conducive to large-scale industrial applications.

[0046] In an optional embodiment, the catalyst is in the form of droplets, which are droplets obtained by pre-preparing a liquid catalyst before the heterogeneous catalytic reaction. The liquid catalyst can be prepared by dissolving at room temperature or by heating and melting. For example, mercury and gallium are in liquid state at room temperature and can be dissolved into liquid state at room temperature. When heating and melting are used, the melting temperature can be controlled to be 2°C higher than the theoretical lowest melting point on the alloy phase diagram. The melting process is relatively mature and the melting temperature required for the single-atom catalyst in the present invention is relatively low. Whether it is the above-mentioned room temperature dissolution or heating and melting method, the preparation process is simple, the conditions are mild, and it is convenient for large-scale production.

[0047] The catalyst can be atomized into liquid droplets by using an atomizing device. In this way, the reactant can be a gas or a liquid and the liquid is a liquid that is immiscible with the liquid catalyst. The atomizing method used by the atomizing device can be pressurized atomization, dual-flow (air / liquid flow or liquid / liquid flow) atomization, ultrasonic atomization, centrifugal atomization, etc. In a specific embodiment, Figure 4 As shown, the reactants are liquids, which are first loaded into a container; under reaction conditions where the reaction temperature is less than 600°C, the catalyst is introduced into the liquid reactants in the form of droplets. The two are immiscible, and the liquid-liquid interface is fully contacted to cause a catalytic reaction. After the catalytic reaction, the product, unreacted products and by-products are separated from the catalyst. The two are immiscible. In a specific embodiment, Figure 5 As shown, the reactant is gas. Under the reaction conditions, the atomized liquid droplets and the gas reactant are introduced into the reaction container to carry out the gas-liquid interface contact reaction.

[0048] In addition, the catalyst can also be heated to evaporate and then condense to form droplets by evaporating the liquid catalyst placed in the reaction container. Wherein, the reactant is a gas. In a specific embodiment, Figure 6 As shown, an evaporation-condensation method is used to form droplets of catalyst in a reaction vessel. After the liquid catalyst evaporates and condenses into droplets, a gaseous reactant is introduced into the area where the droplets are located, so that the gaseous reactant flows through the suspended droplets and undergoes sufficient gas-liquid interface contact reaction with the droplets. The above method for forming droplets is simple to operate, convenient for temperature control, and more conducive to large-scale production and application. Specifically, it includes the following steps: Step 1) The reaction vessel is divided into a bottom high-temperature zone, a middle main reaction zone, and an upper cooling zone. Step 2) The catalyst is added to the bottom high-temperature zone of the reaction vessel and heated to form steam. The steam rises to the middle main reaction zone and the upper cooling transition zone, where it condenses into atomized droplets. The droplets are then suspended in a reflux under the combined action of gravity and the rising hot air flow. The droplets eventually fall in the upper cooling transition zone and are evaporated again in the bottom high-temperature zone. Through continuous evaporation, condensation, and atomization, the reflux droplets are suspended in the middle main reaction zone of the reaction vessel. Step 3) The gaseous reactant is introduced into the middle main reaction zone and fully contacts the reflux suspended droplets to cause a catalytic reaction. In this embodiment, the single-atom catalyst comprises at least two elements selected from the group consisting of transition metals mercury, zinc, alkali metals lithium, sodium, potassium, rubidium, cesium, and alkaline earth metal magnesium. Furthermore, the single-atom catalyst comprises at least two elements selected from the group consisting of transition metals zinc, alkali metals sodium, potassium, and alkaline earth metal magnesium.

[0049] In an alternative embodiment, the catalyst is in the form of droplets formed under the reaction conditions of a heterogeneous catalytic reaction, wherein the reactant is a gas and the catalyst is in the form of droplets and undergoes sufficient interfacial contact with the gaseous reactant to catalyze the reaction.

[0050] For example, methods for forming droplets under the reaction conditions of heterogeneous catalytic reactions, such as Figure 7As shown, the material components of the catalyst are pre-loaded on the surface of a solid support and introduced into a reaction vessel in solid form. Under reaction conditions, the material components on the surface of the solid support are heated and melted into droplets. The gaseous reactant flow introduced into the reaction vessel passes through the support and fully contacts the droplets on the support to cause a catalytic reaction. Under reaction conditions, that is, after heating, the components on the surface of the support melt. Due to the low loading, the material components form molten droplets under the action of surface tension and / or support structure. The loading amount can be determined according to the average particle size of the droplets. The solid support with the catalyst material components loaded on the surface can be prepared by any of the following methods: impregnation, coprecipitation, and vapor deposition. Among them, the wet impregnation method steps: first, the metal source of the material components, the support and the solvent are mixed to obtain a suspension; second, the suspension is filtered and dried to obtain a precursor; then, the precursor is calcined and then reduced in a reducing gas atmosphere to obtain a support-loaded solid alloy catalyst. The co-precipitation method involves adding a precipitant to a solution. After a precipitation reaction, the solution is calcined and reduced to produce a uniformly dispersed support-supported solid alloy catalyst. The solution is a homogeneous solution of multiple cations containing the metal elements of the catalyst material components and the constituent elements of the support. The vapor deposition method involves depositing the metal elements of the catalyst material components onto the support surface via chemical vapor deposition (CVD) and physical vapor deposition (PVD) to form a solid alloy catalyst supported on the support.

[0051] After the carrier-loaded solid alloy catalyst is prepared, it is sprayed directly into the reactor or pre-filled in the reactor in a fixed bed manner. Under the reaction conditions, the material components on the surface of the solid carrier can be heated and melted into droplets, which is a droplet-type single-atom catalyst.

[0052] Another example is a method for forming droplets under the reaction conditions of a heterogeneous catalytic reaction, such as Figure 8 As shown, the catalyst is pre-prepared into an ultrafine powder, which is then sprayed into a reaction vessel. Under reaction conditions, the ultrafine powder is heated to form droplets, allowing the droplets to contact and react with the gaseous reactants simultaneously introduced into the reaction vessel. The ultrafine powder can be prepared, for example, by liquid atomization followed by rapid cooling, electron beam quenching, laser surface melting, or mechanical crushing. Mechanical crushing can include jet milling, high-speed mechanical impact milling, vibration milling, stirred milling, ball milling, sand milling, cyclone milling, high-pressure roller (roller) milling, high-pressure water jet milling, high-pressure homogenization, ultrafine shearing, and ultrasonic crushing.

[0053] In addition, in this optional embodiment, the reaction vessel can be a fluidized bed reactor or a fixed bed reactor. Further, when the reaction vessel is a fluidized bed reactor, the catalyst reacts with the gaseous reactants in the fluidized bed in the form of droplets. The catalyst in the form of droplets in the present invention has the high activity, high efficiency and high catalytic specific surface area of ​​single-atom catalysis, and the time with the reactants in the reaction system is controllable, especially when reacting with gaseous reactants in the fluidized bed, the interface contact is sufficient, the catalytic reaction time is stable and controllable, and the product and the catalyst can be effectively separated. When the reaction vessel is a fixed bed reactor, a solid carrier with a catalyst substance component loaded on the surface is pre-filled in the reactor, and the gaseous reactants flow through the fixed bed to undergo a catalytic reaction.

[0054] Furthermore, if the reactant is a gas, the method further includes collecting droplets and / or cooled powder from the bottom of the reaction vessel, removing impurities to obtain a catalyst, and reusing the catalyst. By collecting the catalyst and separating it from impurities before reuse, the catalyst's service life is extended and production costs are reduced. For example, after the droplets are collected, the product, unreacted products, and by-products that float on the surface or sink to the bottom are separated and reused. The cooled powder is collected by gravity and then activated and regenerated, or the powder is reheated and melted.

[0055] In an alternative embodiment, the heterogeneous catalytic reaction may further include converting gaseous reactants into plasma, introducing the plasma reactants into a container under reaction conditions for a heterogeneous catalytic reaction with a droplet-type catalyst. The plasma reactants fully contact the LSACs, allowing for a catalytic reaction, thereby reducing the activation energy of the reactants and further improving catalytic efficiency.

[0056] The present invention also provides a droplet-type catalyst for use in the aforementioned heterogeneous catalytic method. The droplet-type catalyst refers to a catalyst that, during a heterogeneous catalytic reaction, forms droplets and catalyzes the interfacial contact reaction with the reactants; and under the reaction conditions, the catalyst is in a liquid state in which all components are mutually soluble. The catalyst's chemical composition includes at least one element selected from transition metals, metals with p-electrons in their outer shells, rare earth metals, alkali metals, alkaline earth metals, aluminum, and non-metallic elements such as sulfur, selenium, and tellurium; the chemical composition is derived from components, which can be one or more of a mixture, a single substance, or an inorganic compound.

[0057] In an optional embodiment, the material component is one or more of a halide, a hydroxide, and an oxygen-containing acid, and the melting point of the material component is lower than 1300°C.

[0058] In an optional embodiment, the catalyst is a single-atom catalyst, and its chemical composition includes at least two elements selected from transition metals, metals with p electrons in the outer layer, rare earth metals, alkali metals, alkaline earth metals, metallic aluminum, and non-metallic sulfur, selenium, and tellurium. The catalyst contains at least one chemical component element that exists in a transient quasi-ionic state in the liquid. Through observation and theoretical calculation, it was found that at least some elements of the liquid alloy catalyst are in a transient quasi-ionic and associated single-atom state during the ionization process, and have single-atom catalytic properties, that is, a single-atom catalyst. This quasi-ionic and associated single-atom state refers to the "short-range ordered" cluster structure of the liquid, in which several pairs of clusters (X, Y) are subjected to the combined action of van der Waals forces, thermal motion, fluctuations, and mobile collisions, the valence bonds are destroyed, a cluster X in a pair of clusters is dissociated, and an element x of X is ionized, and the rest of this cluster X is associated as a single atom or free radical, recorded as x'-X c , where x' represents a single anion or cation formed by the cluster X; X c The remaining associated single atoms or radicals of cluster X are represented by another cluster Y, which forms a corresponding cationic / anionic cluster Y'. Subsequently, X' and Y' recombine to form a neutral state. During the period between the dissociation and ionization of cluster X and its recombination, one of the elements exists in a discrete single ion state in the liquid. This, along with the associated single atoms / radicals, becomes a catalytically active center, and the corresponding molecular ion cluster simultaneously becomes another catalytically active center. Liquid-phase alloy catalysts characterized by the transient quasi-ionic state of some elements are known as liquid-phase single-atom catalysts (LSACs).

[0059] In the Bader charge test, the Bader charge of at least two elements in the single-atom catalyst is a fractional, i.e., non-integer, charge. The fractional charge is the result of transient ionization averaging. The Bader charge is obtained by subtracting the apparent electrons of the pseudopotential from the integrated electron density within the Bader volume when calculating the electronic properties of a molten alloy using quantum mechanics and ab initio molecular dynamics. Furthermore, in the Bader charge test, for single-atom catalysts with different chemical compositions but at least one common element, or single-atom catalysts with the same chemical composition but different contents, the smaller the absolute value of the Bader charge, the higher the catalytic activity. Some elemental atoms / clusters carry positive charges, such as gallium (Ga), indium (In), tin (Sn), lead (Pb), and bismuth (Bi), while some carry negative charges, such as Mn, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ru, Ag, Pt, Au, La, Ce, Li, Na, K, Mg, Ca, and Al. Furthermore, based on these characteristics, when liquid-phase, i.e., liquid droplet, single-atom catalysts are applied in various fields, the appropriate catalyst can be selected based on its Bader charge, and its chemical composition and ratios can be determined / adjusted. For example, by performing quantum mechanical calculations on the electronic properties of the liquid catalyst for various formulations, the formulation with the smallest absolute Bader charge value in the calculated results can be selected as the preferred formulation.

[0060] Furthermore, liquid-phase single-atom catalysts exhibit anomalous resistivity characteristics that differ from those of solid-state alloys. For example, under normal circumstances, the resistivity of solid-state alloys increases with increasing temperature and with increasing content of high-resistivity metals, while the resistivity of ionic liquids, including ionic compound melts, decreases with increasing temperature. However, the resistivity temperature coefficient of the single-atom catalysts in the present invention exhibits an anomaly, and even the resistivity of some liquid-phase single-atom catalysts decreases with increasing temperature. Conventional observations and existing theoretical models suggest that alloy melts are not ordinary ionic liquids; therefore, at least some of the elements in the molten binary alloy are in a quasi-ionic state. Furthermore, while the resistivity of solid-state alloys decreases with increasing content of low-resistivity metals, the resistivity variation of liquid-phase single-atom catalysts deviates significantly from that of solid-state alloys, and even the resistivity of some liquid-phase single-atom catalysts increases within a certain composition range with increasing content of low-resistivity metals.

[0061] In addition, as mentioned above, the inventors of the present application have noticed that: compared with the catalyst in which the gas reactant is bubbled into the continuous liquid phase in the form of bubbles, the droplet catalyst has a huge specific surface area, and the unit effective catalytic area is greatly improved; further, the liquid-phase single-atom catalyst in the form of a droplet has the high activity, high efficiency and high catalytic specific surface area (of the droplet) of single-atom catalysis, and the time with the reactant in the reaction system is controllable (especially when reacting with the gaseous reactant in the fluidized bed, the interface contact is sufficient, and the catalytic reaction time is stable and controllable), and the product and the catalyst can be effectively separated. Therefore, based on the highly active liquid-phase single-atom catalyst and the high catalytic specific surface area of ​​the droplet type, the catalytic activity is greatly improved, which is more conducive to large-scale industrial application.

[0062] Compared with the catalytic efficiency per unit catalytic area, the catalytic efficiency per unit catalytic area of ​​liquid phase single atom catalyst is 10 higher than that of non-single atom catalyst. 3 ~10 8 times, the catalytic efficiency is greatly improved, and the single-atom catalyst has ultra-high catalytic performance. The inventors of the present application particularly pointed out that it is based on a profound microscopic mechanism of certain liquid physics: some elements are in the state of quasi-ions and associated single atoms; clusters are dissociated, elements are ionized and monoatomic, and then recombined. Due to the above-mentioned microscopic mechanism, the single ions, associated single atoms / free radicals, and corresponding molecular ion clusters in the reaction process all directly participate in catalysis as active centers with "single-atom" characteristics. Different from solid-state supported single-atom catalysts that only have a single single-atom active center, the LSACs of the method of the present invention have so-called 3-active centers (i.e., single ions, associated single atoms / free radicals, and corresponding molecular ion clusters are all active centers), which can enhance and change the reaction mechanism by combining intermediates to form so-called co-catalytic interactions. Therefore, the single-atom discreteness of LSACs is completely uniform and dynamically stable on a macroscopic scale. In addition to the atomic utilization efficiency, high selectivity, and high reaction kinetics of single-atom catalysis, LSACs possess the uniform active centers of homogeneous catalysts and the structural stability and easy separation of heterogeneous catalysts. They also exhibit quantum size effects, an unsaturated coordination environment, and strong active center-support interactions. The ultra-high catalytic performance per unit catalytic area of ​​these catalysts confirms the single-atom catalytic properties of LSACs. Furthermore, the single-atom catalysts described herein can be used for direct interfacial catalysis without the addition of other reagents, such as water, organic solvents, or salt solutions.

[0063] Furthermore, existing catalytic theory holds that catalytic performance is primarily determined by the content of the catalytically active species, requiring the use of noble metals as active species in many reactions. However, due to the co-catalytic interactions (formed by the aforementioned physical mechanisms), many elements typically considered inert (e.g., metals with p-electrons in their outer shells) exhibit strong catalytic activity in the liquid-phase single-atom catalysts (LSACs) of the present invention. Related examples demonstrate that: 1) even low-content combinations of active metals (e.g., Pt, Ni, and Mn) with high-content inert elements (e.g., Bi, Sn, and In) often exhibit high activity, and the catalytic activity of alloys of active metals and inert elements can even exceed that of 100% active metal; 2) for some active metal / inert element combinations, increasing the inert element content actually enhances catalytic activity; 3) two elements typically considered completely inert to certain reactions, such as Bi-In alloys, also exhibit high catalytic activity; and 4) catalytic experiments and simulations indicate that elements typically considered completely inert to the reaction are enriched on the surface of LSAC melts, and these surface inert species serve as active sites. For example, in the pyrolysis of methane in a Mn-Bi alloy melt, although pure Bi has very low catalytic activity, within the formulation range of LSACs, the electron-deficient Bi sites promote the dissociation of methane, allowing the methyl group to coordinate with a Bi atom (quasi-ion). The Mn quasi-ion and single-atom sites adsorb H, i.e., the 3-active center, all participate in catalysis. Thus, the liquid-phase single-atom catalysts described in the present invention greatly expand the range of available catalysts, avoiding the use of precious and toxic metals in many cases and achieving high catalytic efficiency using a combination of many low-cost elements. For example, because inert metal elements in the liquid-phase single-atom catalyst can also serve as catalytic active centers, the activity of the liquid-phase single-atom catalyst can be adjusted based on the inert metal content.

[0064] In addition, from the perspective of preparation cost and scalability, the cost of liquid-phase single-atom catalysts LSACs is much lower than that of existing supported solid-phase single-atom catalysts, and they are also easy to prepare on a large scale. As we all know, in the solid phase, objects with large surface areas naturally have a tendency to agglomerate, and single atoms have the largest theoretical specific surface area. Therefore, the realization of solid-state supported single-atom catalysts requires overcoming huge surface energy to achieve atomic-level discreteness, which inevitably requires the use of complex and difficult preparation methods, which are costly, difficult to increase the load, and difficult to prepare on a large scale. In addition, the prepared single-atom catalysts are prone to sintering and agglomeration during the reaction process and have poor stability. It is obvious that the preparation method of the liquid-phase single-atom catalyst of the present invention is very simple. After determining the appropriate components and formula, simple process methods such as heating and melting can be used to utilize the microscopic mechanism in the liquid phase given by nature to achieve natural "single atoms (including single ions)" uniform dispersion. Low cost and large-scale preparation are no longer problems. The single-atom catalytic properties remain good during the reaction process, and there is no sintering and agglomeration. In addition, under the reaction conditions, the support of liquid droplet LSACs and supported solid catalysts is different, because in this case, the liquid droplet LSACs are liquid-phase single-atom catalyzed and achieved by a simple method; while supported solid catalysts are either not single-atom catalyzed or have the disadvantages of being difficult to prepare and unstable in the solid-state single-atom catalysis.

[0065] In addition, the chemical composition of the catalyst of the present invention may include transition metals such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, niobium, molybdenum, ruthenium, silver, cadmium, tungsten, rhenium, platinum, gold, and mercury; metals with outer p electrons may include gallium, indium, tin, antimony, lead, and bismuth; rare earth metals may include lanthanum, cerium, praseodymium, neodymium, samarium, and europium; alkali metals may include lithium, sodium, potassium, rubidium, cesium, and francium; and alkaline earth metals may include magnesium and calcium.

[0066] In an optional embodiment, the droplet-shaped single-atom catalyst comprises a chemical composition comprising a first element and a second element. The first element is at least one element selected from the group consisting of transition metals such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, silver, platinum, and gold; alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as magnesium and calcium; and aluminum; and the second element is at least one element selected from the group consisting of metals with p-electrons in their outer shells such as gallium, indium, tin, antimony, lead, bismuth; and rare earth metals such as lanthanum, cerium, and samarium. The first element provides high catalytic activity, while the second element provides a low melting point and low price for the alloy, reducing costs and facilitating large-scale production. Due to the aforementioned co-catalytic interaction, the addition of the second element increases activity in some combinations. Furthermore, the proportion of the second element is no less than 35%. This proportion of the second element provides a low melting point for the single-atom catalyst, ensuring a liquid state under reaction conditions and lowering the requirements for achieving a liquid phase, further facilitating large-scale production. The second element content in the formulation should be moderate. If it is too low, it will not be able to form a liquid under the reaction conditions and will not be able to undergo interfacial catalytic reactions with the reactants in the LSAC manner. Preferably, the second element accounts for no less than 65%. Due to the aforementioned co-catalytic interaction, in some combinations, increasing the second element content also increases activity.

[0067] In addition, in some applications, the first element in the chemical composition of the liquid-phase single-atom catalyst is selected from the transition metals manganese, nickel, platinum, iron, silver, and ruthenium. This formula combination can provide higher activity for the liquid-phase single-atom catalyst of the present invention and improve the catalytic efficiency. In some applications, the first element in the chemical composition of the single-atom catalyst is selected from at least one of the transition metals titanium, vanadium, chromium, cobalt, zinc, molybdenum, alkali metal lithium, alkaline earth metal magnesium, and metal aluminum. This formula combination can provide higher activity for the liquid-phase single-atom catalyst of the present invention in some catalytic reactions and improve the catalytic efficiency, while the metal price is relatively low. In some applications, the single-atom catalyst may not use Ga-Pt, Ga-Ru, Ga-Au, or ternary or multi-element alloy catalysts formed by chemical elements thereof and other elements. Pt, Ru, and Au are rare and expensive precious metals, with prices of hundreds of RMB per gram. They are not only two orders of magnitude more expensive than Ag and Mo, but also thousands or even tens of thousands of times more expensive than metals such as Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. Ga is the most expensive liquid metal. The high activity of single-atom catalysis avoids the use of the above-mentioned alloy combinations, has good economic benefits, and is more conducive to the realization of low-cost large-scale preparation.

[0068] In a preferred embodiment, the single-atom catalyst comprises at least two first elements in its chemical composition. Specifically, the first elements are selected from at least two of the transition metals titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, silver, platinum, gold, the alkali metals lithium, sodium, potassium, the alkaline earth metals magnesium and calcium, and the metallic aluminum element. The use of a combination of at least two first elements and at least one second element can unleash the synergistic catalytic effects of multiple active metal elements and enhance catalytic efficiency. Further preferably, the first element is selected from the transition metals manganese, nickel, platinum, iron, silver, and ruthenium. This combination can provide the liquid-phase single-atom catalyst of the present invention with higher activity and improved catalytic efficiency.

[0069] In a preferred embodiment, the single-atom catalyst comprises a first element and a second element, wherein the first element comprises at least metallic manganese. The single-atom catalyst is formed by combining manganese with one or more second elements, such as manganese-bismuth, manganese-lanthanum, manganese-cerium, manganese-samarium, manganese-cerium-bismuth, and manganese-bismuth-tin. Alternatively, the single-atom catalyst is formed by combining manganese and another first element with one or more second elements, such as manganese-copper-bismuth, manganese-lithium-bismuth, manganese-nickel-bismuth, and manganese-nickel-tin. In particular, when the first element contains manganese, the calculated absolute value of the non-integer Bader charge of the manganese alloy melt is smaller than that of alloy melts formed by traditional highly active catalysts such as platinum and nickel with the corresponding second element, and exhibits higher catalytic activity in various classical reactions than traditional highly active catalysts. Furthermore, the alloy has a low melting point, particularly the manganese-bismuth alloy, which allows for applications in catalytic reactions with lower reaction temperatures. Furthermore, the relatively low price of manganese (lower than that of non-ferrous metals such as copper and nickel, and significantly lower than that of precious metals) also contributes to cost reduction.

[0070] In another alternative embodiment, the single-atom catalyst comprises at least two of the second element selected from the group consisting of gallium, indium, tin, antimony, lead, and bismuth, each with a p-electron outer shell, i.e., the first element is absent. This preferred combination of ingredients can provide higher activity and a lower alloy melting point, expanding the low-temperature application range of the liquid-phase single-atom catalyst of the present invention.

[0071] The droplet-type catalyst provided by the present invention can be widely used in any reaction process including dehydrogenation, hydrogenation, olefin hydroformylation, ammonia-related reactions, petroleum refining catalytic reactions, biomass catalytic utilization, organic pollutant treatment, and polymer material regeneration. These include, but are not limited to: 1) methane thermal cracking, methane dry reforming, methane steam reforming, methane coupling to ethylene, methane oxygen-free coupling to aromatics, ethane dehydrogenation / oxidative dehydrogenation, propane dehydrogenation / oxidative dehydrogenation, C4 and above alkane dehydrogenation and oxidative dehydrogenation, ethylbenzene dehydrogenation, butane-carbon dioxide coupling to light aromatics, and dehydrogenation reactions such as thermal cracking of aromatic hydrocarbons, polyolefins, and asphalt. 2) hydrogenation reactions such as olefin hydrogenation or acetylene hydrogenation, as well as olefin hydroformylation. 3) ammonia-related reactions such as ammonia decomposition, ammonia synthesis, ammonia oxidation, nitrobenzene to aniline, SCR denitrification, etc. 4) petroleum refining catalytic reactions. 5) biomass catalytic utilization, organic pollutant treatment, and polymer material regeneration reactions.

[0072] Compared with the prior art, some embodiments of the present invention also have the following advantages:

[0073] 1. Under reaction conditions, the catalyst, in the form of droplets, directly interfaces with the reactants for heterogeneous catalytic reactions, improving catalytic efficiency and enabling heterogeneous catalytic reactions using liquid catalysts. Droplet-type catalysts offer high activity, good catalytic stability, controllable reaction conditions, and scalable production, making them suitable for a wide range of applications.

[0074] 2. The droplet-type catalyst has a huge specific surface area, and the effective catalytic area can be 10 times higher than that of the commonly used bubbling method. 3 -10 8 For example, when gaseous reactants are introduced into a continuous liquid-phase catalyst by bubbling, the bubble size is on the order of 1 cm, while the droplets can often achieve a particle size of 10 nm to 1 mm. Moreover, the time the droplets spend with the reactants in the reaction system is effectively controllable (especially when reacting with gaseous reactants in a fluidized bed, effective contact is sufficient, and the catalytic reaction time is stable and controllable).

[0075] Furthermore, droplet-type single-atom catalysts combine the high activity and efficiency of single-atom catalysis with dynamic stability. In addition to the atomic utilization efficiency, high selectivity, and high reaction kinetics of single-atom catalysis, they also possess the uniform, single active center of homogeneous catalysts and the structural stability and easy separation of heterogeneous catalysts.

[0076] 3. The catalyst adopts a single-atom catalyst, which realizes the low-cost, large-scale, high-quality preparation of the catalyst for heterogeneous reactions in an economical way. Even if a noble metal is adopted, only a trace amount or even a trace amount is required to be added, which greatly reduces the material cost. In addition, in order to further reduce the cost, cheap and resource-rich elements can be used to replace the noble metals in the past. For example, Mn, Fe, Ni, Bi, Ce, La, Cu, Zn, Al, Mg, S, etc. are used to replace Rh, Pt, Ru, Pd, Au, Ir, etc. Moreover, the preparation method mainly relies on melting the elements in the formula according to the stoichiometric ratio. The method is simple and the quality is uniform and controllable, the preparation cost is low, and large-scale production can be carried out.

[0077] 4. The process conditions are mild and controllable, the separation is simple and efficient, and the separated catalyst is easy to regenerate and activate. In the present application, the single-atom catalyst uses a metal as a matrix, and is a metal with a low melting point and high density. The entire system can work at low and medium temperatures, and can also have a larger range of selectivity to match the process. For strong endothermic or exothermic reactions, the melt has a much higher heat capacity than the gas phase, and the segmented temperature control of the reaction tower allows the temperature to be controlled within a range that is conducive to the positive reaction, and is also conducive to heat recovery. When used, the reaction gas only needs to meet the reaction conditions and overcome the gravity of the metal to have a larger space velocity, while conventional supported catalysts need to provide a larger power consumption to overcome gas resistance. The present invention is more conducive to the large-scale preparation and application of the catalyst.

[0078] 5. The present invention can have extremely wide applications. As a platform-type technical method and a huge range of formula combinations, the present invention can be widely used in methane thermal cracking, methane dry reforming, methane steam reforming, methane coupling to ethylene, methane oxygen-free coupling to aromatics, ethane dehydrogenation / oxidative dehydrogenation, propane dehydrogenation / oxidative dehydrogenation, C4 and above alkane dehydrogenation and oxidative dehydrogenation, ethylbenzene dehydrogenation, olefin hydrogenation, acetylene hydrogenation, synthetic ammonia, ammonia decomposition, ammonia oxidation, SCR denitrification, petroleum catalytic reforming, FCC fluid catalytic cracking, biomass catalytic utilization, pollutant treatment and polymer material regeneration, etc.; in particular, it provides large-scale engineering emission reduction and carbon reduction, and uses carbon dioxide to produce materials, chemicals and energy. The application of the present invention in the above-mentioned fields has high efficiency, low cost, simple process and good stability.

[0079] 6. Single-atom catalysts can be combined in multiple ways to achieve synergistic catalysis with multiple elements. For example, as mentioned in the optional embodiments above, a combination of at least two second elements can be used, or a combination of a first element and a second element can be used, or a combination of at least two first elements and a second element can be used, as in the preferred embodiment.

[0080] 7. The present invention is reliable and environmentally friendly in the entire process chain of catalyst processing, use, recovery and heterogeneous catalytic reaction process.

[0081] The droplet-type catalyst, heterogeneous catalytic method, and application of the present invention will be further described below with reference to specific examples and comparative examples:

[0082] Example 1 (High-pressure molten pool + atomizing nozzle)

[0083] Catalytic reaction experimental equipment Figure 2 As shown, it includes a reaction device and a catalyst injection device.

[0084] The reaction device mainly includes a reaction vessel, a heating device for heating the reactor, a detection device connected to the reaction vessel, and a reactant introduction device. It may also include other supporting devices, such as an auxiliary heating device, a temperature detection device such as a multi-point temperature measuring thermocouple, and a heat insulation device such as a heat insulation quartz bead and quartz sand. Figure 2 As shown, the heating device is a vertical tubular furnace with a stainless steel outer sleeve and a quartz crucible as the reaction vessel, with the quartz crucible serving as the main reactor. The stainless steel sleeve prevents the safety hazard of quartz breaking at high temperatures and causing alloy leakage. The quartz crucible, serving as the main reactor, eliminates interference from metal vessels in catalysis. The inertness of quartz essentially does not react with the Mn-based alloy catalyst selected in this example.

[0085] like Figure 2 As shown, the upper and lower ends of the tube furnace are respectively encapsulated with insulation layers (including insulation boards, insulation cotton, etc.), and the quartz crucible reactor extends into the tube furnace and extends a distance above and below the insulation layer and is exposed to the air to form an upper air-cooling zone and a lower air-cooling zone. The lengths of the lower air-cooling zone and the upper air-cooling zone are 150 mm and 250 mm, respectively. A heating constant temperature zone is formed in the area enclosed by the upper and lower insulation layers and the crucible reactor. The effective lengths of the heating constant temperature zone are 400, 800 and 1200 mm, respectively. In the reaction device, the length of the reaction zone is consistent with the length of the heating constant temperature zone. Multiple reactions can be carried out simultaneously. For example, multiple reactors can be installed on a bracket, and catalytic experiments with 1-10 groups of different catalyst formulations can be carried out at a time. The bracket is placed in a vertical tube furnace with multi-stage controlled heating, and the bottom of the bracket is supported and insulated by ceramic insulating material.

[0086] In addition, if Figure 2 As shown, a particle collector is provided at the bottom of the reaction device to collect and reuse the catalyst.

[0087] The catalyst injection device includes: an autoclave with a graphite molten pool for alloy smelting, a high-pressure gas bottle connected to the autoclave to increase the pressure inside the autoclave, an outlet of the graphite molten pool connected to the reaction device through a pipe, and an atomizing device is provided at the end of the pipe. In this embodiment, the atomizing nozzle located in the reaction device specifically adopts the following method: Figure 1Of course, the atomizing device described in the present invention is not limited thereto, for example, Figure 1 As shown in the figure, one of the following can be used: a. Double (gas) flow atomization structure, b. High pressure Laval nozzle, c. Double roller centrifugal atomization. Double (gas) flow atomization structure means that the melt and high pressure gas enter from the central channel and the channel located on the periphery of the central channel respectively and then spray out to form droplets. High pressure Laval nozzle means that the melt and high pressure gas enter from the central channel and the channel located on the periphery of the central channel respectively and then spray out to form droplets. Figure 1 The specific structure shown (the channel diameter first decreases and then increases) allows the melt to enter the channel, forming droplets. Twin-roller centrifugal atomization involves two rollers rotating at high speeds in opposite directions, with the melt entering through the channel between the rollers to form droplets. Alternatively, centrifugal atomization involves the melt dripping onto a high-speed rotating disc due to gravity. Centrifugal force then throws the melt outward, forming droplets. This reaction occurs in the atomization zone outside the cylinder.

[0088] Before the catalytic experiment begins, the alloy is melted. Specifically, the catalyst components are placed into a graphite melt according to the recipe. The temperature is gradually raised to 1050°C and held for 4 hours while maintaining an Ar gas purge. Hydrogen is then used to reduce the liquid catalyst melt, which is then cooled to the reaction temperature. The melt is placed in an autoclave with a maximum operating pressure of 8 MPa.

[0089] Heterogeneous catalytic reactions were conducted in quartz crucibles with total lengths of 800 mm, 1200 mm, and 1600 mm, respectively. Unless otherwise specified, the reactor diameter (ID) is 25 mm, and the quartz crucible length is 1200 mm. An atomizer, one end connected to the molten pool and the other extending from the top of the reactor, sprayed the catalyst from the molten pool into the crucible in the form of droplets. Simultaneously, a gas mass flowmeter (MFC) introduced the mixed feed gases from above through a fine quartz tube into the crucible reaction zone, reaching the measured temperature. K-type thermocouples inserted into the crucible measured the temperature at multiple points during the reaction. The reaction products were analyzed by online mass spectrometry (MS) and gas chromatography (GC). Headspace effects were further corrected using reaction data from selected inert metals.

[0090] Liquid droplet catalyst (LdCs catalyst) alloy formula:

[0091] Mn alloys containing inert metals such as Bi and Sn, 0.01% Mn-99.99% Bi, 10Mn-90Bi (i.e., 10% Mn-90% Bi, at%, referred to herein unless otherwise specified), 30Mn-70Bi, and 10Mn-90Sn. These alloy catalysts exhibit single-atom catalytic properties and, under the reaction conditions, react in a droplet-like form, representing liquid-type single-atom catalysts (LdSACs). All other alloy catalysts provided in the examples herein are single-atom catalysts unless otherwise specified.

[0092] In this example, the following heterogeneous catalytic reactions were performed to evaluate the performance of the catalyst:

[0093] (1) EDH ethane dehydrogenation to ethylene: The reaction pressure was set at 0.1 MPa. After the above experimental device was purged, catalyst droplets were sprayed from the top. The droplets were formed by the melt drawn from the molten pool and the 0.4 MPa high-pressure nitrogen gas through the atomizing nozzle through the air flow atomization. The average particle size of the droplets was 40 μm after calculation and the laser reflection measurement in advance. The average injection amount was 6 mg / min. The droplets fell to the bottom of the container after suspension. The catalyst alloy was collected at the bottom afterwards. At the same time, the reaction raw materials 80 sccm C2H6 and 70 sccm Ar were introduced into the reaction zone at the measured temperature point. The catalytic performance of the above catalysts at reaction temperatures of 550 ° C, 700 ° C, 750 ° C, and 775 ° C was respectively investigated, including ethane conversion, ethylene selectivity and ethylene yield (including headspace). The experimental time was 12, 24 and 120 h, respectively. The results are shown in Table 1:

[0094] Table 1 Catalytic data of droplet-type heterogeneous catalyst in ethane dehydrogenation to ethylene

[0095]

[0096] It should be noted that the experimental maintenance time has no effect on the catalytic efficiency.

[0097] Furthermore, the inventors of the present application have found that when the second element content is less than 70%, it is not conducive to the formation of a droplet-type catalyst, and further, it is not conducive to the progress of the reaction.

[0098] In addition, if Figure 1 As shown, a particle collector is provided at the bottom of the reaction device to collect and reuse the catalyst. In a further scaled-up device, the catalyst is collected and other solid substances are separated, and the alloy is re-melted and recycled.

[0099] (2) Quartz crucibles of the same height have the same catalytic efficiency under different injection rates

[0100] In a 1600mm quartz crucible, the catalytic efficiency of 30Mn-70Bi catalyst droplets at different injection rates was compared. The results showed that in the same quartz crucible height, the average catalyst injection rates of 12mg / min, 6mg / min, and 4mg / min produced essentially the same catalytic efficiency.

[0101] Comparative Example 1 (30Mn-70Bi alloy bubbling catalysis, non-droplet type)

[0102] The EDH ethane dehydrogenation reaction to ethylene is carried out in a bubble column with a total length of 150 mm. The length of the bubble column is measured from the gas bubbling point at the bottom of the crucible to the top of the constant temperature heating zone. Insulation at the upper and lower ends of the constant temperature heating zone in the tubular furnace heating zone is provided by multiple layers of insulation materials, such as mica boards and asbestos, placed on the top of the reaction crucible, and ceramic insulation at the bottom of the crucible, respectively. A 30 mm alloy melt intersecting the insulation barrier outside the heating zone serves to reduce pure thermal reactions in the headspace. The crucible outside the insulation barrier is exposed to air and maintained cool by an external fan. The reactor headspace effect above the melt surface is further corrected using reaction data from selected inert metals. K-type thermocouples inserted into the melt measure the melt temperature in real time at multiple points during heating, insulation, and bubbling reactions. The vent tube orifice diameter ID = 2 mm, based on calculations of a single bubble diameter of ~1 cm, a residence time of ~1 s in a 150 mm melt, a gas volume of 0.5 ml, and a catalytic area between the bubble and the alloy melt of 3 cm. 2 The catalytic performance of smelting 30Mn-70Bi alloy, reaction pressure 0.1MPa, reaction raw material 30sccm (feed ratio 25% C2H6, 75% Ar), reaction temperature 750℃, ethane conversion rate 55.2%, ethylene yield 49.5% (including headspace).

[0103] Comparison of Catalytic Efficiency: Based on Comparative Example 1, assuming a 25% bubble occupancy rate in the melt for large-scale production, a 3.5-fold increase in the volume of the heated feedstock, a slightly increased reaction volume, and a 4-fold increase in the average volume, the vent tube orifice diameter ID = 2 mm, a single bubble diameter d ~ 1 cm, a 15 cm melt residence time t ~ 1 s, a bubble gas volume v ~ 0.5 ml, an alloy density ~ 9 g / ml, and a product / mass catalytic efficiency of 3.1 ml ethylene / g catalyst / hour. In contrast, the mass catalytic efficiency in this example is 6666.7 ml ethylene / g catalyst / hour. Clearly, the catalytic efficiency in this example is significantly superior to that in Comparative Example 1.

[0104] Cost comparison:

[0105] In the (1) EDH ethane dehydrogenation to ethylene of Example 1, only 260 g of the 30Mn-70Bi catalyst is used in 30 days and can be reused after separating the by-products, thereby reducing the catalyst cost.

[0106] According to (2) of the first embodiment, if the catalyst residence time is increased by 10 times after scale-up, the catalytic efficiency can be increased by 10 times, that is, 26 g of 30Mn-70Bi catalyst has the same effect as (2) of the first embodiment.

[0107] Moreover, the cost of the catalyst mainly lies in the atomization and collection cycle costs, among which the atomization energy consumption cost is the main one, which does not exceed 8 yuan / kg. According to the present embodiment, the cost of each catalyst (agent) can produce 10,385g of ethylene, that is, the catalytic cost per ton of ethylene is 96.3 yuan, which is much lower than the cost of existing conventional catalysts.

[0108] (3) PDH propane dehydrogenation to propylene:

[0109] The reaction pressure was set at 0.1 MPa. After the experimental apparatus was purged, catalyst droplets were sprayed from the top. The droplets were formed by atomizing the melt drawn from the 0.8 MPa high-pressure molten pool through a Laval nozzle. Calculations and prior laser reflection measurements showed that the average droplet size was 20 μm, and the injection rate was 4 mg / min. Simultaneously, 60 sccm of the reaction raw material C3H8 was introduced into the reaction zone at the measured temperature point. The catalytic performance of each catalyst at reaction temperatures of 675°C and 700°C was examined, including propane conversion, propylene selectivity, and propylene yield (including headspace). The results are shown in Table 2.

[0110] Table 2 Catalytic data of droplet-type heterogeneous catalyst in PDH propane dehydrogenation to propylene

[0111]

[0112] At the above-mentioned temperatures of 675°C and 700°C, the 30Mn-70Bi alloy was reacted for 120 hours. After the reaction, the solid material at the bottom was collected and reheated to 700°C under nitrogen protection. The powder on the molten surface of the alloy was sucked out to obtain ~28.7g of alloy.

[0113] Comparative Example 2 (Pt / Sn / Al2O3 supported catalyst)

[0114] PDH mainstream UOP process: The catalyst uses <1wt% Pt and 1-2wt% Sn loaded on Al2O3; <1wt% Na or K is used as an additive; the catalyst is in a flowing state during the production process and is regenerated in the final regeneration device (CCR).

[0115] During regeneration, chlorine-oxygen mixed gas is introduced to remove carbon deposits and redisperse Pt. The regenerated catalyst flows back into the first reactor to ensure the continuous dehydrogenation reaction. The propane mass space velocity is 3h -1 The conversion rate of the four stages is 35%. Since Pt clusters inevitably grow together during the sintering process, the catalyst must be completely replaced after 4 years, and the loss is 20% per year.

[0116] Compare:

[0117] In comparative example 2, 0.6 wt% Pt is used. Based on the platinum price of 350 yuan / g, the material cost of the platinum component of the catalyst is 2.1 yuan / g. Considering the preparation cost of 2.4 yuan / g, each catalyst can produce 1312 g of propylene.

[0118] In this embodiment, only 173 g of the 30Mn-70Bi catalyst is used in 30 days, and the catalyst can be reused after separating the by-products. According to Example 1 (2), after scale-up, increasing the catalyst residence time by 10 times can increase the catalytic efficiency by 10 times. Moreover, the catalyst cost mainly lies in the atomization and collection cycle costs, of which the atomization energy consumption cost is mainly less than 8 yuan / kg, and the loss is 3%. According to this embodiment, the cost of each catalyst (agent) can produce 11.92 kg of olefins (propylene + ethylene), that is, the catalytic cost per ton of olefins is 83.9 yuan.

[0119] It can be seen that, in terms of catalyst, the cost of PDH propane dehydrogenation to propylene in Example 1 (3) is only 1 / 9 of that in Comparative Example 2.

[0120] (4) DRM methane and carbon dioxide dry reforming to produce synthesis gas:

[0121] The reaction pressure was set at 0.1 MPa. After purging, the experimental device was sprayed with catalyst droplets from the top. The droplets were formed by ultrasonic atomization of the melt drawn from the 0.2 MPa high-pressure molten pool. The average particle size of the droplets was 20 μm according to calculation and previous laser reflection measurement. The injection rate was 4 mg / min. At the same time, 20 sccm CH4 and 10 sccm CO2 were introduced into the reaction zone at the measured temperature point. The catalytic performance of the 10Mn-90Bi catalyst was investigated at a reaction temperature of 1000°C. The results showed that the methane conversion rate was 49.3%, the carbon dioxide conversion rate was 99.8%, the hydrogen yield was 43.2%, and the carbon monoxide yield was 89.5% (excluding the head space).

[0122] Example 2 (High-pressure molten pool + centrifugal atomization)

[0123] The catalytic reaction experimental device is the same as that in Example 1

[0124] LdCs catalyst alloy formula: 8Mn-10Ni-72Ce, 18Mn-58Bi-24Sn

[0125] As before, the alloy was melted and loaded into the molten pool according to the recipe and the loading of each component. The temperature was raised in stages to 1050°C and held for 12 hours while maintaining an Ar purge. The LdCs catalyst melt was then reduced with hydrogen to the reaction temperature.

[0126] SCR-NH3 denitrification reaction:

[0127] (1) The reaction pressure was set at 0.1 MPa. After purging the experimental apparatus, 8Mn-10Ni-72Ce and 18Mn-58Bi-24Sn catalyst droplets were sprayed from the top. The droplets were formed by centrifugal atomization from a melt drawn from a 0.2 MPa high-pressure molten pool. Calculation and prior laser reflection measurements showed an average droplet size of 20 μm. The injection rate was 40 mg / min. Simultaneously, a mixture of 1 sccm NH3, 1 sccm NO, and 8 sccm Ar was introduced into the reaction zone at the measured temperature. The catalytic performance of the catalysts was investigated at a reaction temperature of 650°C. The NO conversions were 99.99% and 99.97%, respectively. The reaction was continued for 10 h with no change in catalytic efficiency.

[0128] In addition, adding 1 sccm of SO2 to the reaction raw material mixture did not change the catalytic efficiency much. Using the control Sn droplets, the NO conversion rate was less than 1%.

[0129] (2) 18Mn-58Bi-24Sn alloy, quartz crucible total length 1600mm, catalyst droplets are formed by atomizing the melt drawn from a 0.8MPa high-pressure molten pool with 0.4MPa high-pressure nitrogen through an atomizing nozzle. The average droplet size is 20μm according to calculation and previous laser reflection measurement. The injection rate is 40mg / min. The top diameter is increased to enable the nozzle to spray horizontally. The high-pressure nitrogen flow forms a swirl. Simulated dusty coal flue gas with a flow rate of 600sccm is introduced into the reaction zone at the measured temperature of 480℃. Other conditions are the same as above. As a result, no NO and dust are detected. The reaction gas is stopped and replaced with nitrogen. The solid matter at the bottom is collected to obtain nanocarbon, dust and catalyst alloy.

[0130] Comparative Example 3

[0131] The experimental apparatus of Comparative Example 1 was used to refine an 18Mn-58Bi-24Sn alloy. The reaction pressure was set at 0.1 MPa. After purging and pretreatment, 60 sccm of simulated dusty coal-fired flue gas was introduced. The catalytic performance of the catalyst at a reaction temperature of 480°C was examined in a 300 mm bubble column. After 120 hours of reaction, no NO was detected, but a small amount of carbon and dust accumulated on the filter of the outlet pipe.

[0132] Comparison of mass catalytic efficiency: Comparative Example 3, based on a 25% bubble occupancy rate in the melt, an average volume expansion of 2.5 times upon heating, a vent hole diameter ID = 2 mm, a single bubble diameter d ~ 1 cm, a 30 cm melt residence time t ~ 2 s, a bubble gas volume v ~ 0.5 ml, a catalyst alloy density ~ 9 g / ml, and a flue gas / mass catalytic efficiency of 20 ml flue gas / g catalyst·h. The mass catalytic efficiency of Example 2 (2) is 15,000 ml flue gas / g catalyst·h, which is much better than that of Comparative Example 1.

[0133] Cost comparison: In addition, in Example 2 (2), only 1728g of catalyst was used in 30 days, and it can be reused after separating the by-products. The cost of the catalyst mainly lies in the atomization and collection cycle costs, among which the atomization energy consumption cost is the main one, which does not exceed 8 yuan / kg. According to the present embodiment, the cost of each catalyst (agent) can treat 1905L of dust-containing coal-fired flue gas, and the treatment efficiency can be increased by 10-100 times after scale-up.

[0134] Comparative Example 4:

[0135] Commercially available honeycomb catalysts were used for SCR-NH3 denitrification. Honeycomb catalysts have an active component (V2O5) on a carrier (WO3 / TiO2), a flow area of ​​approximately 80%, are wear-resistant, and are easily regenerated. Denitrification of simulated coal-fired flue gas was performed at 480°C. The two processes are as follows:

[0136] (1) High-temperature denitrification followed by low-temperature dust removal. In this process, the denitrification catalyst is exposed to high-concentration dust and flue gas for a long time, resulting in serious catalyst wear, clogging, and poisoning, which shortens the catalyst life, reduces denitrification efficiency, and increases operating costs. Waste vanadium and titanium catalysts are hazardous wastes and are toxic to the environment and human body. They are densely arranged and difficult to disassemble.

[0137] (2) High-temperature electrostatic dust removal followed by low-temperature denitrification. Although this process has a certain effect on extending the life of the catalyst, the dust removal effect still cannot achieve the effect of preventing wear, clogging, and poisoning. The dust removal and denitrification processes are still two independent devices, occupying a large area, with poor synergistic functions and poor ultra-low emission stability; the pollution problem of waste vanadium and titanium catalysts still exists.

[0138] Compare:

[0139] Comparative Example 4, using (1) high-temperature denitration followed by low-temperature dust removal, inevitably results in the denitration catalyst being exposed to high-concentration dusty flue gas for a long period of time. Flue gas dust is a major cause of catalyst wear, clogging, and poisoning, which shortens the catalyst life, reduces denitration efficiency, and increases operating costs.

[0140] Since the catalyst of Example 2 (1) does not deactivate for a long time, it shows that the liquid high-density alloy of the catalytic system can withstand high temperature and high dust and high ash - the smoke and dust quickly float out of the melt, without affecting the catalytic activity, and can also resist the poisoning of sulfur oxides. The catalyst of Example 2 (2) does not deactivate for a long time, which shows that the liquid droplet alloy of the catalytic system can withstand high temperature and high dust and high ash; therefore, it does not affect the catalytic activity and can be arranged in the high-temperature section before dust removal; there is no ammonia residue; there is no toxic metal pollution. Compared with Comparative Example 4, Example 2 (2) also has the function of removing smoke and dust.

[0141] Therefore, the above catalytic system has much better performance than existing catalysts in SCR-NH3 denitrification.

[0142] Example 3

[0143] The catalytic reaction experimental device is the same as that in Example 1

[0144] LdCs catalyst alloy formula: 0.5Cu-3Ag-96.5Ga

[0145] The crucible was modified from the previous example, using a graphite-lined stainless steel pressure crucible. Before the catalytic experiment began, the alloy was melted. The components were loaded into the molten pool according to the recipe, and the temperature was raised in stages to 650°C. The temperature was then held for 4 hours while maintaining an Ar purge. The catalyst was then reduced with hydrogen to produce a LdCs catalyst melt, which was then cooled to the reaction temperature. Observational and theoretical calculations confirmed that the liquid-phase catalyst exhibited single-atom catalytic properties, and the resulting droplets were identified as liquid single-atom catalysts (LdSACs).

[0146] Ethylene oxidation reaction to EO:

[0147] The reaction pressure was set at 2 MPa and the temperature was 230°C. After purging, the experimental apparatus was sprayed with catalyst droplets. The droplets were atomized by nitrogen flow from a melt drawn from a 5 MPa high-pressure melt pool. Calculated and pre-measured by laser reflectometry, the average droplet size was 20 μm. The injection rate was 30 mg / min. Simultaneously, a reaction feed gas mixture was introduced at a flow rate of 200 sccm. The composition (mol concentration) was: C₂H₄ 60%, O₂ 15%, CO₂ 3%, with the balance being N₂. The experimental results showed an ethylene conversion of 26% and an EO selectivity of 89%.

[0148] Example 4

[0149] The catalytic reaction experimental device is the same as that in Example 1

[0150] LdCs catalyst alloy formula: 2Cu-2Zn-96In

[0151] The crucible was modified from the previous example, using a graphite-lined stainless steel pressure crucible. Before the catalytic experiment began, the alloy was melted. The components were loaded into the molten pool according to the recipe, and the temperature was raised in stages to 750°C. The temperature was then maintained for 4 hours while maintaining an Ar purge. The catalyst was then reduced with hydrogen to produce a LdCs catalyst melt, which was then cooled to the reaction temperature. Observational and theoretical calculations confirmed that the catalyst exhibited single-atom catalytic properties, resulting in the liquid droplet single-atom catalyst (LdSACs).

[0152] Synthesis gas to methanol reaction:

[0153] The reaction pressure was set at 5 MPa and the reaction temperature was 260°C. After purging, the experimental apparatus was sprayed with catalyst droplets. The droplets were formed by atomizing a nitrogen stream from a melt drawn from an 8 MPa high-pressure molten pool. Calculated and pre-measured by laser reflectometry, the average droplet size was 15 μm. The injection rate was 10 g / min. Simultaneously, a raw gas mixture with a molar composition of 50% H₂, 5% CO₂, and 25% CO₂ was introduced at a flow rate of 100 sccm. The results were: a CO conversion of 46.9%, a CO₂ conversion of 53.2%, a methanol selectivity of 76.1%, and a methanol yield of 37.9%.

[0154] Example 5 (evaporation condensation atomization droplets)

[0155] Figure 3 The evaporation, condensation, and atomization droplet catalytic device used in the fifth embodiment is schematically shown.

[0156] LdCs catalyst alloy formula: Mg, Zn and Mg-Zn alloy

[0157] Catalytic reaction experimental equipment Figure 2 As shown, the heating device includes a vertical tubular furnace with a bottom filled with quartz sand and an auxiliary heating device thereon; the main reactor is a quartz crucible with a diameter ID = 20 mm and a total length of 1000 m, and also includes other supporting devices.

[0158] The bottom metal and alloy section is heated to 1150°C in a tube furnace and kept warm, with a heating zone of 200mm, to evaporate Mg and Mg-Zn alloy;

[0159] Two sections of 680-700℃ auxiliary electric heating are set in the middle and upper middle parts respectively to prevent the metal and alloy from solidifying, and temperature is measured at multiple points in the upper, middle and bottom parts.

[0160] The top 200 mm crucible is exposed to the air and kept cool by an external fan in the air; the mixed gas is introduced into the reactor from above through a pipeline using a gas mass flow meter MFC and analyzed by an online mass spectrometer MS and a gas chromatograph GC. Figure 3 As shown, insulating quartz beads are placed between the air-cooled and upper-middle regions to create temperature zones, where only a negligible amount of metal vapor rises to the quartz beads and avoids the air-cooled areas. When the temperature drops below 907°C, Mg and Zn condense into liquids, with numerous droplets forming a thin mist in the reaction zone. These droplets reflux and suspend under the combined effects of gravity and the rising hot air flow. Finally, they descend from the upper cooling zone below the insulating quartz beads to the bottom high-temperature zone, where they are evaporated. Low-boiling-point elements, through continuous evaporation, condense, and atomize, form reflux droplets, which suspend in the main reaction zone in the middle of the reactor vessel.

[0161] The crucible was filled with 10Zn-90Mg and Mg alloy respectively. The filling height was 50mm.

[0162] (1) Methane thermal cracking to produce hydrogen and co-produce graphene and CNT.

[0163] The reaction gas volume was 600 sccm, with a methane / hydrogen ratio of 1:1. Vent tubes were inserted into the crucible's lower chamber at 950°C, 1000°C, and 1150°C, respectively. The reaction time was 2 hours. The reaction results are as follows:

[0164] Table 3 Catalytic data of graphene and CNT in the co-production of hydrogen from methane pyrolysis

[0165] Temperature Metal and alloy formulations <![CDATA[CH4 conversion rate %]]> 950 Mg 83.3 950 10Zn-90Mg 89.7 1000 Mg 91.2 1000 10Zn-90Mg 95.5 1150 Mg 98.1 1150 10Zn-90Mg 99.9

[0166] After the reaction is completed, the solid powder is pressed into blocks and evaporated and demetallized at a high temperature of 1200°C. The remaining product is analyzed by SEM and TEM to be a highly crystalline nanocarbon product - a mixture of carbon nanotubes and graphene.

[0167] Further reducing the metal Mg filling height to 10 mm, the conversion rate decreased by less than 1%, indicating that the catalytic area produced by less catalyst atomized condensed droplets has basically achieved the catalytic effect. The main impact is the unevenness of the atomized droplets and the airflow and the mass transfer limitation.

[0168] Comparative Example 5: (Bubble Catalysis)

[0169] The Mg loading amount was measured according to the bubble column length of 160 mm and loaded into the quartz crucible. The temperature was raised to 1050°C in stages and kept warm for 2 h. Ar gas was kept purged and the Mg catalyst melt was reduced with hydrogen. The melt was cooled to the reaction temperature of 950°C. The reaction raw gas volume was 10 sccm, methane / hydrogen = 1:1, a vent tube was inserted into the bottom of the crucible, and a methane conversion rate of 33.8% was obtained by the bubbling method. The reaction time was 12 h.

[0170] After the reaction was completed, the metal was evaporated at a high temperature of 1200° C., and the remaining product was analyzed by SEM and TEM to be a mixture of highly crystalline nano-carbon products, but the carbon yield was only 3.4% of the above example.

[0171] Comparison shows that the volume / mass efficiency of the atomized condensation droplet catalysis of this embodiment is at least 10 higher than that of the bubbling method catalysis of the comparative example 5. 4 times.

[0172] The efficiency of the droplet method is calculated according to the conventional method of those skilled in the art. The droplet diameter is 20 μm, and the diffusion coefficient in the gas is generally 10 -5 ~10 -4 m 2 / s range, take 0.1-0.3cm 2 / s, take 0.2cm2 / s, and each droplet can catalyze 0.0084ml / s of raw materials per second (average diffusion radius 0.126cm / s), and the corresponding catalyst volume is 4*10 - 9 ml, the difference between the two is 2.1*10 6 Even if we consider the mass transfer efficiency of 0.25, because the heating and reaction volume increase by 8 times, the droplet method can catalyze ~10 6 ml cold raw gas / ml catalyst·s.

[0173] In industry, the proportion of bubbles in the bubble column to the melt, i.e., the bubble occupancy rate, is generally 0.2-0.25. For example, the bubble diameter is 1 cm = 0.5 ml of raw gas, and 1 ml of melt catalyst volume can catalyze 0.1 ml of raw gas.

[0174] It can be seen that the volume / mass efficiency of gas droplet catalysis is 10 higher than that of bubble catalysis. 4 -10 6 This is also confirmed by the above comparison.

[0175] In addition, for each embodiment of the present invention, according to conventional methods that can be used by those skilled in the art, the average diameter of the catalyst droplets can be reduced to the order of 0.1-10 μm, which can further increase the catalyst droplet diameter by 10 μm. 3 -10 9 times the efficiency.

[0176] (2) n-Butane and carbon dioxide coupling to produce BTX and light hydrocarbons.

[0177] The crucible was loaded with 90Zn-10Mg, with a total alloy mass of 2g. The reaction gas flow rate was 60sccm, with a CO2 / n-butane ratio of 0.95. Vent tubes were inserted into the crucibles, and the temperature was 550°C. The reaction lasted for 10 hours. Results: CO2 conversion of 33%, n-butane conversion of 99%, and aromatics selectivity of 87%.

[0178] Comparative Example 6:

[0179] Wei Changcheng, Zhang Wenna, Yang Kuo, Bai Xiu, Xu Shutao, Li Jinzhe, Liu Zhongmin. An efficient way to use CO2 as chemical feedstock by coupling with alkanes[J]. Chinese Journal of Catalysis, 2023, 47:138-149.

[0180] Coupling of n-butane with carbon dioxide to produce BTX and light hydrocarbons.

[0181] The HZSM-5 sample was calcined at 600°C in a muffle furnace for 5 h, then pelletized, crushed, and sieved to 40-60 mesh for reaction evaluation. 0.4 g of the prepared catalyst was loaded into a stainless steel fixed-bed reactor containing a quartz tube (6 mm id). n-Butane and carbon dioxide gases were introduced into the catalyst bed controlled by a seven-star mass flowmeter. The reaction temperature was 500°C. The contact time was varied by adjusting the catalyst weight (0.025-0.8 g), while keeping other reaction conditions constant. The n-butane mass space velocity was ~0.1 h -1 Under the optimized reaction conditions, when the CO2 / n-butane ratio was 0.475, the CO2 and n-butane conversions reached 17.5% and 100%, respectively, and the aromatics selectivity reached 80%.

[0182] Compare:

[0183] In this example, 2 g of the catalyst can produce 26.2 kg / year of aromatic hydrocarbons. In fact, the catalyst is almost not consumed, and the catalytic cost is only the heating cost (which largely overlaps with the reaction heating cost), so the cost is basically negligible.

[0184] The molecular sieve of comparative example 6 costs RMB 7,000-15,000 / t, taking RMB 10 / kg, and assuming a service life of one year, the annual aromatics production is 720 g / g catalyst / year, which means that each catalyst can produce 72 kg of aromatics.

[0185] Therefore, this example, while utilizing a low-cost catalyst, simple equipment, and high yield, achieves higher n-butane mass space velocity, CO conversion, n-butane conversion, and aromatics selectivity than Comparative Example 6. Because bottom carbon deposits do not affect catalysis, the stability of this example is significantly superior to that of the comparative example. Even in larger-scale equipment, carbon deposits can be easily removed.

[0186] Example 6 (Powder sprayed into the reaction zone to form droplets under reaction conditions)

[0187] The LdCs catalyst is a prefabricated ultrafine powder. The 10Mn-90Bi formula is selected. The ultrafine powder is prepared by two methods: atomizing the catalyst liquid followed by rapid cooling, and melting the catalyst and cooling it followed by jet milling.

[0188] The catalyst liquid is rapidly cooled after atomization: the alloy is first smelted, and the catalyst components are loaded into a graphite melt according to the recipe. The temperature is then raised in stages to 1050°C and held for 4 hours while maintaining an Ar gas purge. The LdCs catalyst melt is then reduced with hydrogen and cooled to the reaction temperature. The melt is then placed in an autoclave equipped with an atomizing nozzle (maximum operating pressure 8MPa). The melt is then atomized by a 0.5MPa high-pressure nitrogen nozzle and sprayed into a stainless steel storage tank. The melt is then naturally cooled to form an ultrafine powder. The average particle size of the powder is 30μm, as calculated and measured by laser reflection. Nano-silica is sprayed simultaneously with the catalyst at a 1:1 volume ratio to provide dispersion.

[0189] The catalyst is melted and cooled, and then the air flow mill is used to crush the alloy block. The alloy is melted in the same way as above, and after cooling, the alloy block is crushed by air flow mill.

[0190] The catalytic reaction experimental setup still utilizes the aforementioned vertical tube furnace, stainless steel outer tube, quartz crucible, and other supporting equipment. Reactions are conducted in quartz crucibles with a total length of 1000 mm. Ultrafine catalyst powder from a stainless steel storage tank is introduced into the crucible from the top using nitrogen. Simultaneously, a mass flowmeter (MFC) is used to introduce the mixed feed gases from above through a thin quartz tube into the center of the crucible. The length of the reaction zone matches the length of the constant-temperature heating zone, which is insulated by the upper and lower ends of the tube furnace heating zone (600 mm long) and multiple layers of insulation, such as mica sheets, ceramics, and asbestos, at the top and bottom of the crucible (150 mm and 250 mm long, respectively). Outside the insulation layer, the top and bottom of the crucible are exposed to air and maintained cool by an external fan to minimize the effects of pure headspace heat reactions. Headspace effects are further corrected using reaction data from selected inert metals. K-type thermocouples in the crucible measure the temperature at multiple points in real time during the reaction. The analysis was performed using an online mass spectrometer (MS) and a gas chromatograph (GC).

[0191] DRM methane carbon dioxide dry reforming to produce synthesis gas reaction:

[0192] The reaction pressure was set at 0.1 MPa and the reaction temperature was 1000°C. After purging the experimental apparatus, the atomized quenched catalyst powder was sprayed into the apparatus through a nitrogen flow at a rate of 10 mg / min. The sprayed catalyst powder melted into droplets in the reaction zone. At the same time, 20 sccm CH4 and 10 sccm CO2 were introduced as reaction raw materials. The results showed a methane conversion rate of 38.7%, a carbon dioxide conversion rate of 99.3%, a hydrogen yield of 34.5%, and a carbon monoxide yield of 81.5%.

[0193] The catalytic efficiency of the powdered catalyst using a jet mill (same steps as above) is also high, but slightly lower than that of the atomized quenched powdered catalyst.

[0194] Example 7 (Catalyst components are supported on the surface of the carrier and form droplets under reaction conditions)

[0195] Liquid drop catalyst LdCs loaded on a carrier. The catalyst material components are loaded on the carrier, heated and melted on the carrier, and melt droplets are formed under the action of the surface tension of the catalyst material components and / or the carrier structure. The details are as follows:

[0196] The 3Ni-1Mo-96Bi catalyst was liquid at 500°C using in-situ high-temperature XRD and in-situ high-temperature energy dispersion spectroscopy. Therefore, the supported metal element concentration and relative atomic mass were calculated according to the formula, and then the metal ion mass of the corresponding salt was weighed: nickel nitrate hexahydrate (Ni(NO3)2·6H2O), ammonium heptamolybdate ((NH4)6Mo7O 24 ) and bismuth nitrate (Bi(NO3)3) were dispersed in a 2% dilute nitric acid solution according to the Ni:Mo:Bi ratio of 3:1:96. The solution was ultrasonically vibrated for 30 minutes, and the above solution was added dropwise to 2 times the mass of ZSM-5 molecular sieve and stirred evenly. After grinding with a mortar, the modified catalyst was reduced with H2 in a 550℃ tube furnace for 5 hours, cooled and ground again to obtain ZSM-5 supported metal modified ZSM-5 molecular sieve catalyst Ni 0.03 Mo 0.01 Bi 0.96 / ZSM-5, stored in a stainless steel tank in a sealed and dry place.

[0197] The MTOAH methane-free direct reaction to olefins, aromatics, and hydrogen was performed at a reaction pressure of 0.1 MPa and a temperature of 750°C. The experimental apparatus described in Example 5 was purged and then sprayed with a nitrogen stream at a rate of 0.4 g / min. Simultaneously, 200 sccm of CH₄ was introduced as a feedstock. A methane conversion of 16.7% and an aromatics selectivity of 97.1% were achieved. The catalyst powder was periodically collected and re-added to the system, and the catalytic efficiency remained unchanged over 12 hours.

[0198] Example 8 (alloy droplets, molten salt droplets)

[0199] Alloy 8Mn-8Li-84Bi and molten salt 15MnCl2-30LiCl-55KCl droplets were formed as in Example 2, and the droplet-type 3Ni-1Mo-96Bi catalyst was still prepared according to Example 6.

[0200] Ammonia synthesis was performed using a quartz crucible at atmospheric pressures of 450 and 500°C, with a reaction gas flow rate of 30 sccm and an N:H ratio of 1:3.17. (1) Alloy droplets were formed by centrifugal atomization from a melt drawn from a 0.2MPa high-pressure molten pool. Calculations and prior laser reflection measurements revealed an average droplet size of 20 μm, with a spray rate of 40 mg / min. (2) 3Ni-1Mo-96Bi / ZSM-5 were simultaneously sprayed in at a rate of 4 g / min for catalytic reaction. (3) 15MnCl2-30LiCl-55KCl mixed molten salt droplets were formed by centrifugal atomization from a melt drawn from a 0.2MPa high-pressure molten pool. Calculations and prior laser reflection measurements revealed an average droplet size of 60 μm, with a spray rate of 50 mg / min. The results are as follows:

[0201] Table 4 Catalytic data

[0202] Temperature Metal and alloy formulations Synthetic ammonia yield% 450 8Mn-8Li-84Bi 0.14 450 3Ni-1Mo-96Bi / ZSM-5 0.23 450 <![CDATA[15MnCl2-30LiCl-55KCl]]> 0.88 500 8Mn-8Li-84Bi 0.11 500 3Ni-1Mo-96Bi / ZSM-5 0.25 500 <![CDATA[15MnCl2-30LiCl-55KCl]]> 0.71

[0203] Comparative Example 7 (Melt Catalyst)

[0204] Ammonia synthesis was performed in a quartz crucible. The smelted alloy formula 8Mn-8Li-84Bi and the mixed salt formula 15MnCl2-30LiCl-55KCl catalyst were loaded into the crucible with a liquid column measuring length of 30cm. The catalytic reactions were carried out at atmospheric pressure, 450°C and 500°C, with a reaction gas flow rate of 30sccm and an N:H ratio of 1:3.17. The results are as follows:

[0205] Table 5 Catalytic data of comparative example 7

[0206] Temperature Metal and alloy formulations Synthetic ammonia yield% 450 8Mn-8Li-84Bi 0.06 450 <![CDATA[15MnCl2-30LiCl-55KCl]]> 0.37 500 8Mn-8Li-84Bi 0.08 500 <![CDATA[15MnCl2-30LiCl-55KCl]]> 0.38

[0207] Comparative Example 8

[0208] The current industrial ammonia synthesis Haber-Bosch process is implemented under high temperature and high pressure conditions (450-550°C, pressure 10-30 MPa), consuming 1%-2% of the world's total energy supply; at the same time, it emits approximately 500 million tons of carbon dioxide each year, accounting for about 1.8% of global carbon dioxide emissions. Fused iron catalysts are still the mainstream catalysts in industrial production.

[0209] Comparison: Exploring efficient ammonia synthesis catalysts beyond molten iron catalysts is a relentless pursuit within the chemical industry. Since low temperatures favor higher conversion rates, better catalysts must operate at lower temperatures. Compared to Comparative Example 8, the melting points of the alloy 8Mn-8Li-84Bi and the 15MnCl2-30LiCl-55KCl molten salt catalysts in Example 8 are both below 300°C, and the melting point of the 3Ni-1Mo-96Bi / ZSM-5 catalyst is no higher than 440°C. Therefore, the catalysts in this Example exhibit superior catalytic performance at operating temperatures. Compared to Comparative Example 7, under the same formulation, the liquid drop catalyst in this Example demonstrates superior efficiency to conventional melt catalysts.

[0210] Example 9 (molten pool + centrifugal atomization)

[0211] Catalyst alloy formula: Li-Mg, Na, K, 50Li-50Ca.

[0212] OCM oxidative coupling of methane to ethylene.

[0213] As in Example 1, before the catalytic experiment began, the alloy was melted. The components were loaded into the molten pool according to the recipe and the loading ratios. The temperature was then raised in stages to 1050°C and held for 12 hours while maintaining an Ar purge. The catalyst was then reduced with hydrogen to produce an LdCs catalyst melt, which was then cooled to the reaction temperature. Observations and theoretical calculations confirmed that the catalyst exhibited single-atom catalytic properties, resulting in the liquid droplet single-atom catalyst, LdSACs.

[0214] The reaction pressure was set at 0.1 MPa. After purging, the experimental apparatus was sprayed with catalyst droplets. The droplets were formed by centrifugal atomization of melt drawn from a 0.2 MPa high-pressure molten pool. Calculations and prior laser reflection measurements indicated an average droplet size of 20 μm. The injection rate was 40 mg / min. Simultaneously, a mixture of 300 sccm of the reaction raw materials (30% methane, 30% carbon dioxide, and 40% Ar) was introduced. The catalytic performance of the catalyst was examined at a reaction temperature of 680°C. The results are as follows:

[0215] Table 6 Catalytic data in OCM methane oxidative coupling to ethylene

[0216] Temperature Metal and alloy formulations Methane conversion rate% C2 selectivity % 680 50Li-50Mg 41 66 680 Na 29 76 680 K 24 71 680 Li 18 59 680 50Li-50Ca 37 70

[0217] Comparative Example 9

[0218] The LSACs catalyst alloy formula is shown in Table 7 below.

[0219] OCM methane oxidative coupling to ethylene: Using a graphite crucible, the alloy was melted before the catalytic experiment began. The components were loaded into the crucible according to the recipe and bubble column length. The temperature was raised in stages to 1050°C and held for 12 hours while maintaining an Ar purge. The catalyst was then reduced with hydrogen to produce a LSACs catalyst melt, which was then cooled to the reaction temperature. The bubbling method was used with a reaction gas flow rate of 30 sccm: 30% methane, 30% oxygen, and 40% Ar. The catalytic reaction results are as follows:

[0220] Table 7 Catalytic data of comparative example 9

[0221] Temperature Metal and alloy formulations Methane conversion rate% C2 selectivity % 800 10Li-10Mn-80Bi 26 75 800 50Li-50Mg 15 63 800 10Na-10Mn-Bi 28 76 800 10K-10Mn-80Bi 22 72 800 50Li-50Ca 13 61 800 30Li-10Mn-60Bi 33 79

[0222] It can be seen that the droplet method achieves better reaction results than the bubbling method at a lower reaction temperature and a larger reaction gas flow rate. Therefore, the droplet method heterogeneous catalysis of the present invention is more conducive to large-scale catalytic production.

[0223] Example 10 (Catalyst S and Catalyst Se)

[0224] The experimental method and experimental apparatus are the same as those in Example 5, using evaporation, condensation, and atomization. Although the catalyst is a single-element catalyst of S and Se and does not have single-atom catalytic properties, the single-element catalyst catalyzes in the form of droplets, thereby improving the catalytic reaction efficiency.

[0225] Catalyst formula: S, Se.

[0226] Experimental study on the reduction of nitrobenzene to aniline using CO / H₂O catalyzed by sulfur and selenium. The bottom evaporation zone temperature was 250°C, the reaction feedstocks were 5 sccm of NH₃ and 5 sccm of argon, and the temperature range was 220-240°C. The feedstock gas nozzle was positioned in the middle of the measured temperature range.

[0227] Dinitrobenzene (1 mmol / min) and pure water (1 mmol / min) were continuously introduced into a quartz crucible reactor with an initial CO atmosphere through a pipeline heated to 215°C, along with 50 sccm of CO. After 30 minutes, the exhaust gas collected from the 215°C pipeline was pumped back into the reactor through a high-temperature pipeline and allowed to react for 2 hours. Aniline content was determined using a gas chromatograph with an FID detector, maintaining a column temperature of 150°C and a vaporizer temperature of 250°C.

[0228] The conversion rates of S and Se nitrobenzene and the yields of aniline were 88.2% and 67.1% and 83.7% and 58.5% respectively.

[0229] Example 11 (3Se-97Te)

[0230] The experimental method and experimental device are the same as above, and the evaporation condensation atomization method is adopted.

[0231] (1) Methane and carbon dioxide dry reforming.

[0232] Reaction raw materials: methane 5sccm, carbon dioxide 3sccm, argon 2sccm

[0233] Catalyst Te.

[0234] The bottom evaporation zone temperature is 1150°C, the interval temperature is 650-950°C, and the raw gas pipe outlet is located in the middle of the measured interval temperature. CH4 conversion rate is 41% and CO2 conversion rate is 56%.

[0235] (2) Propane dehydrogenation. Reaction raw materials: propane 5sccm, argon 5sccm

[0236] Catalyst Te, 3Se-97Te.

[0237] The bottom evaporation zone temperature was 1150°C, with a range temperature of 600-750°C. The feed gas nozzle was located in the middle of the measured temperature range. The Te and 3Se-97Te catalytic reaction results were: propane conversions of 37% and 49%, olefin yields of 25% and 33%, C2H4 selectivities of 39% and 38%, and C3H6 selectivities of 58% and 59%, respectively.

[0238] Example 12

[0239] MnCl2, LiCl, and KCl are pre-loaded onto an alumina support using a wet impregnation method. The catalyst formula is: Alumina-supported mixed salt catalyst 15MnCl2-30LiCl-55KCl / Al2O3. MnCl2, LiCl, and KCl are dissolved in water according to the stoichiometric ratio to form a 1% dilute solution. The solution is ultrasonically vibrated for 60 minutes. The aqueous solution is then added dropwise to a twice-mass active Al2O3 ceramic support and stirred evenly for wet impregnation. The sample is sealed and allowed to stand for 24 hours. The sample is then dried in a vacuum oven at 105°C for 24 hours and ground evenly in a mortar to obtain the mixed salt catalyst 15MnCl2-30LiCl-55KCl / Al2O3 supported on the Al2O3 ceramic support. The catalyst is then stored in a sealed, dry place in a storage tank.

[0240] The reaction was conducted in a 300mm-long quartz crucible. The reaction zone was filled with 50mm quartz beads (OD = 30µm), 200mm catalyst, and 50mm quartz beads (OD = 30µm). A mass flowmeter (MFC) was used to introduce the mixed raw gas into the crucible from the bottom. The length of the reaction zone matched the length of the constant-temperature heating zone, which was insulated by a tubular furnace at the top and bottom, and by multiple layers of insulation, such as mica, ceramic, and asbestos, at the top and bottom of the crucible (150mm and 250mm in length, respectively). Outside the insulation, the top and bottom of the crucible were exposed to air and kept cool by an external fan to minimize the effects of pure headspace reactions. Headspace effects were further corrected using reaction data from selected inert metals. A K-type thermocouple in the crucible measured the temperature in real time during the reaction. The reaction pressure was set at 0.1 MPa and the reaction temperature was set at 450°C. After purging, the reaction gas was introduced into the experimental apparatus at a flow rate of 60 sccm. The N:H ratio was 1:3.1, and a synthetic ammonia yield of 0.91% was obtained, reflecting the improvement of the catalytic efficiency after the catalytic area of ​​the droplet catalyst was increased.

[0241] In addition, this application also compares the droplet type and bubble column bubbling methods of each embodiment in turn.

[0242] The embodiment includes: according to the same device structure and reaction mode as Example 1 (atomized droplets) and Comparative Example 1 (bubble column bubbling method), 5Mn-95Sn, 10Mn-90Sn, 18Mn-82Sn, 16.1Mn-83.9Ce, 25Mn-75Ce, 3.6Ni-96.4Pb, 13Ni-71Bi-16Sn, 3.9Ni-13Mn-67.5Bi-15.6Sn, 10Ni-20Mn-70Bi, 18Ni-72Ce, 20Ni-35Ce- 45La, 20Ni-25Ce-30La-25Sm, 5Pt-95Pb, 5Pt-95Ga, 5Pt-95Bi, 5Pt-95In, 5Pt-95Sn, 10Pt-90Pb, 10Pt-90Ga, 10Pt-90Bi, 16.7Fe-83.3Ce, 27.5Fe-72.5Sm, and 8.5Fe-91.5La were subjected to EDH reaction, and the same conclusions as in Example 1 and Comparative Example 1 were obtained, i.e., the catalytic volume efficiency and catalyst cost of the former are much better than those of the latter.

[0243] Example 13 (Preparation of a Catalyst Supported on a Solid Carrier Surface)

[0244] The Mn-Bi and Ni-Bi catalysts were pre-loaded on the surface of alumina solid support by vapor deposition method.

[0245] The supported metal element concentration and relative atomic mass were calculated according to the formula. The metal ion mass of the corresponding mass of the salt was weighed: bismuth nitrate (Bi(NO3)3) was dispersed in a 2% dilute nitric acid solution. The solution was ultrasonically vibrated for 30 minutes, then added dropwise to twice the mass of alumina and stirred evenly. The modified catalyst was then ground in a mortar and placed in a 550°C tube furnace with H2 reduction for 5 hours. After cooling, it was ground again to obtain a bismuth-supported alumina powder.

[0246] The metal Mn, Ni and Bi-loaded alumina powders were placed in a vacuum evaporation device respectively, and the vacuum was roughly pumped to above 6.6 Pa. The front stage of the diffusion pump was opened to maintain the vacuum, and the diffusion pump was pumped to 6×10 -3 Pa background vacuum; heat the powder under high vacuum to remove moisture and desorb the gas adsorbed on the powder surface; after reaching the vacuum degree, first pass a low-power electricity to the evaporation source to preheat the plating materials Mn and Ni (blocked by the baffle), and then input a higher-power electricity to quickly heat the plating materials to the evaporation temperature. During evaporation, remove the baffle and perform high-temperature evaporation; after the evaporation is completed, cool and remove the powder to obtain the Mn-Bi alloy catalyst and Ni-Bi alloy catalyst pre-loaded on the surface of the alumina solid support. Because it is difficult for hydrogen to reduce MnO to zero-valent Mn at high temperatures, 0 , vapor deposition can solve the loading problem of difficult-to-reduced metals.

[0247] The description of the present invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as are suited for specific applications.

Claims

1. A heterogeneous catalytic method in which a catalyst in the form of droplets contacts the reactants at the interface, characterized in that: Under the reaction conditions, the catalyst performs interfacial contact catalytic reaction with the reactants in the form of droplets, wherein the particle size of the droplets is 1 nm to 0.1 mm.

2. The heterogeneous catalysis method according to claim 1, characterized in that: The catalyst is in the form of droplets, which are droplets prepared in advance by preparing a liquid catalyst before the heterogeneous catalytic reaction.

3. The heterogeneous catalysis method according to claim 2, characterized in that: An atomizing device is used to atomize a liquid catalyst into droplets; wherein the reactant is a gas or a liquid, and the liquid and the liquid catalyst are immiscible; when the reactant is a gas, the atomized droplets and the gaseous reactant are introduced into a reaction vessel to carry out a gas-liquid interface contact reaction; when the reactant is a liquid, the atomized droplets are introduced into a reaction vessel containing the liquid reactant to carry out a liquid-liquid interface contact reaction.

4. The heterogeneous catalysis method according to claim 2, characterized in that: The liquid catalyst placed in the reaction container is evaporated and condensed to form droplets by heating, evaporation and recondensation; wherein the reactant is a gas, and after the liquid catalyst evaporates and condenses into droplets, the gaseous reactant is introduced into the area where the droplets are located, so that the gaseous reactant and the droplets undergo a gas-liquid interface contact reaction.

5. The heterogeneous catalysis method according to claim 1, characterized in that: The catalyst is in the form of droplets, which are droplets formed under the reaction conditions of a heterogeneous catalytic reaction; wherein the reactant is a gas, and the catalyst in the form of droplets undergoes sufficient interface contact catalytic reaction with the gas reactant.

6. The heterogeneous catalysis method according to claim 5, characterized in that: The method for forming droplets under the reaction conditions of heterogeneous catalysis is: The catalyst components are pre-loaded on the surface of a solid support and introduced into a reaction vessel in solid form. Under reaction conditions, the components on the surface of the solid support are heated and melted into droplets, so that the gaseous reactants flow through the support and fully contact the droplets on the support. Alternatively, the catalyst is pre-prepared into ultrafine powder, which is sprayed into a reaction vessel. Under reaction conditions, the ultrafine powder is heated to form droplets, so that the droplets come into contact with the gaseous reactants simultaneously introduced into the reaction vessel for reaction.

7. The heterogeneous catalysis method according to claim 6, characterized in that: The reaction vessel is a fluidized bed reactor or a fixed bed reactor, wherein, when it is a fluidized bed reactor, the catalyst reacts with the gaseous reactants in the fluidized bed in the form of droplets; when it is a fixed bed reactor, a solid carrier with catalyst material components loaded on its surface is pre-filled in the reactor, and under reaction conditions, the material components on the surface of the solid carrier are heated and melted into droplets, and the gaseous reactants flow through the fixed bed to undergo a catalytic reaction.

8. The heterogeneous catalysis method according to claim 1, characterized in that: The reactant is a gas, and the method further comprises: collecting liquid droplets and / or powder after cooling at the bottom of the reaction container, removing impurities to obtain a catalyst, and recycling the catalyst.

9. A droplet-type catalyst for the heterogeneous catalysis method according to any one of claims 1 to 8, characterized in that: The droplet-type catalyst refers to a catalyst that undergoes interfacial contact catalytic reaction with reactants in the form of droplets during a heterogeneous catalytic reaction; and the catalyst is in a liquid state in which all material components are mutually soluble under the reaction conditions; the catalyst, whose chemical composition includes at least one element selected from transition metals, metals with p electrons in the outer layer, rare earth metals, alkali metals, alkaline earth metals, metallic aluminum, and non-metallic sulfur, selenium, and tellurium; the chemical composition is obtained from material components, and the material components are one or more of a mixture, a single substance, and an inorganic compound.

10. The droplet-type catalyst according to claim 9, characterized in that The catalyst is a single-atom catalyst, the chemical composition of which includes at least two metal elements selected from transition metals, metals with p-electron outer shells, rare earth metals, alkali metals, alkaline earth metals, and metallic aluminum; and at least one chemical component element exists in a transient quasi-ionic state in the liquid; wherein the quasi-ionic state of the single-atom catalyst is manifested in the presence of non-integer Bader charges of at least two elements; for liquid-phase single-atom catalysts with different chemical compositions but the same elements, or for liquid-phase single-atom catalysts with the same chemical composition but different contents, the smaller the absolute value of the Bader charge, the higher the catalytic activity; the Bader charge is obtained by subtracting the explicit electrons of the pseudopotential from the integrated electron density within the Bader volume when calculating the electronic properties of the molten alloy using quantum mechanics ab initio molecular dynamics.

11. The droplet-type catalyst according to claim 10, characterized in that The quasi-ionic state of the single-atom catalyst is also characterized by an anomalous characteristic different from the resistivity of solid alloys; the catalytic efficiency per unit catalytic area of ​​the single-atom catalyst is higher than that of non-single-atom alloy catalysts by 10 3 ~10 8 times; The single-atom catalyst is in a liquid state under reaction conditions in which all material components dissolve in each other, and is achieved by: dissolving into a liquid state at room temperature before the reaction, heating and melting into a liquid state before the reaction, or heating and melting into a liquid state under reaction conditions.

12. The droplet-type catalyst according to claim 10, characterized in that The catalyst is used for direct interface contact catalysis with reactants without adding other reagents.

13. The droplet-type catalyst according to claim 10, characterized in that The transition metals include titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, niobium, molybdenum, ruthenium, silver, cadmium, tungsten, rhenium, platinum, gold, and mercury; the metals with p electrons in the outer layer include gallium, indium, tin, antimony, lead, and bismuth; the rare earth metals include lanthanum, cerium, praseodymium, neodymium, samarium, and europium; the alkali metals include lithium, sodium, potassium, rubidium, cesium, and francium; and the alkaline earth metals include magnesium and calcium.

14. The droplet-type catalyst according to claim 13, characterized in that The liquid-phase single-atom catalyst has chemical components selected from at least two elements selected from the group consisting of metal gallium, indium, tin, antimony, lead, and bismuth, each of which has a p-electron outer layer.

15. The liquid droplet catalyst according to claim 13, characterized in that The liquid-phase single-atom catalyst has a chemical composition comprising a first element and a second element, and the proportion of the second element is not less than 35%; wherein the second element is at least one element selected from metals with p electrons in the outer layer, such as gallium, indium, tin, antimony, lead, bismuth, rare earth metals lanthanum, cerium, and samarium; and the first element is at least one element selected from transition metals, such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, silver, platinum, gold, alkali metals, lithium, sodium, potassium, alkaline earth metals, magnesium, calcium, and metal aluminum.

16. The droplet-type catalyst according to claim 15, characterized in that The first element is at least two selected from transition metals titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, silver, platinum, gold, alkali metals lithium, sodium, potassium, alkaline earth metals magnesium, calcium, and metal aluminum.

17. The droplet-type catalyst according to any one of claims 15 to 16, characterized in that: The first element is selected from transition metals such as manganese, nickel, platinum, iron, silver, and ruthenium.

18. The droplet-type catalyst according to any one of claims 15 to 16, characterized in that: The first element includes at least metallic manganese.

19. The droplet-type catalyst according to claim 9, characterized in that The material component is one or more of a halide, a hydroxide, and an oxygen-containing acid, and the melting point of the material component is lower than 1300°C.

20. Use of the droplet-type catalyst according to any one of claims 9 to 19, characterized in that: The invention is applied to any reaction process of dehydrogenation reaction, hydrogenation reaction, olefin hydroformylation reaction, ammonia-related reaction, petroleum refining catalytic reaction, biomass catalytic utilization, organic pollutant treatment and polymer material regeneration, wherein the dehydrogenation reaction is methane thermal cracking, methane dry reforming, methane steam reforming, methane coupling to ethylene, methane oxygen-free coupling to aromatics, ethane dehydrogenation / oxidative dehydrogenation, propane dehydrogenation / oxidative dehydrogenation, C4 and above alkane dehydrogenation and oxidative dehydrogenation, ethylbenzene dehydrogenation, butane carbon dioxide coupling to light aromatics, aromatic hydrocarbons, polyolefins or asphalt thermal cracking reaction; the hydrogenation reaction is olefin hydrogenation or acetylene hydrogenation; the ammonia-related reaction is ammonia decomposition, ammonia synthesis, ammonia oxidation, nitrobenzene to aniline or SCR denitrification reaction.

Images