Method for producing light olefins by dehydrogenation using a combustion additive containing a transition metal

Abstract

A method for producing light olefins by dehydrogenation may include operating a catalytic dehydrogenation process, monitoring the composition of combustion gas in a combustor to detect the concentration of one or more hydrocarbons, and selectively adding a combustion additive together with a catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of a lower flammability level of the combustion gas at the temperature and pressure of the combustor. The jet cup wear index of the combustion additive may be greater than the jet cup wear index of the catalyst. The combustion additive may include from 1 wt% to 10 wt% of one or more transition metals excluding gallium and precious metals, from 0 parts per million by weight (ppmw) to 100 ppmw of gallium and precious metals, and at least 85 wt% of a carrier.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Application No. 63 / 352,013, filed on June 14, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] Embodiments described herein generally relate to chemical processing, and more specifically, to methods and systems for producing light olefins.

Background Art

[0003] Light olefins such as propylene can be used as base materials for producing many different materials such as polypropylene, isopropanol, and acrylic acid, and these materials can be used, for example, in packaging, construction, and fabrics. As a result of this utility, there is a global demand for light olefins. Suitable processes for producing light olefins generally depend on a given chemical feedstock and include those that utilize fluid catalysts. For example, light olefins can be formed by catalytic dehydrogenation of alkanes in a fluidized bed reactor. However, improvements in the systems and related catalysts used to make light olefins are needed.

Summary of the Invention

[0004] Methods and related systems for producing light olefins by dehydrogenation can include reacting a hydrocarbon-containing feed over a catalyst in a reactor. Following the endothermic dehydrogenation reaction, the catalyst is passed through a combustor where it is heated by combustion of an auxiliary fuel. The catalyst provides both dehydrogenation activity in the reactor and combustion activity in the combustor for combustion of the auxiliary fuel. Sometimes, the dehydrogenation rate is sufficient, but the combustion rate may be lower than the desired rate. For example, in some embodiments, it has been found that over time, the catalytic activity of the catalyst decreases more for combustion than for dehydrogenation. In other embodiments, process variations such as the composition of the auxiliary fuel may require additional catalytic activity for combustion. In some conventional systems, to maintain acceptable dehydrogenation activity and / or to maintain acceptable auxiliary fuel combustion activity, a new catalyst is added to the system to compensate for performance losses due to catalyst aging and / or catalyst attrition. Loss of catalyst combustion activity can limit the available fuel compositions, which can negatively impact the economics or flexibility of the process.

[0005] The catalyst systems and methods for producing olefins of the present disclosure can efficiently maintain dehydrogenation catalyst activity in a reactor and maintain sufficient combustion activity in the combustor of the system. In one or more embodiments, this is at least partially achieved by utilization of both a catalyst and a combustion additive selectively added to the process when the combustion activity is lower than desired. The combustion additive may include less than 100 ppmw of gallium and a noble metal used for dehydrogenation activity, thereby reducing the economic cost of the materials. However, the combustion additive can selectively promote combustion activity as needed. Further, the combustion additive can have a higher attrition rate than the catalyst, thus allowing removal of the combustion additive from the system separately from removal of the catalyst. In some embodiments, the different attrition characteristics of the catalyst and the combustion additive can reduce dilution of the catalyst in the system, thereby improving the catalytic activity of the catalyst while reducing the economic cost of the process.

[0006] According to one or more embodiments of the present disclosure, a method for producing light olefins by dehydrogenation includes operating a catalytic dehydrogenation process, monitoring the composition of combustion gas in a combustor to detect the concentration of one or more hydrocarbons, and selectively adding a combustion additive together with a catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of a lower flammability level of the combustion gas at the temperature and pressure of the combustor. Operating includes contacting a hydrocarbon-containing feed with a catalyst in a reactor to form an olefin-containing effluent, at least partially separating the olefin-containing effluent from the catalyst, passing the catalyst through a combustor, and heating the catalyst by combusting an auxiliary fuel, wherein the auxiliary fuel contains methane in an amount of 1 mol% or more, and passing the catalyst from the combustor to the reactor such that at least a portion of the catalyst continuously circulates between the reactor and the combustor. The jet cup abrasion index of the combustion additive is greater than the jet cup abrasion index of the catalyst, and the jet cup abrasion is measured at a threshold of 45 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams. The combustion additive contains one or more transition metals excluding gallium and noble metals in an amount of 1 wt% to 10 wt%, gallium and noble metals in an amount of 0 parts per million by weight (ppmw) to 100 ppmw, and at least 85 wt% of a carrier.

[0007] It should be understood that both the foregoing general description and the following detailed description are intended to provide an overview or framework for explaining various embodiments and understanding the nature and characteristics of the claimed subject matter. Additional features and advantages of the embodiments will be apparent to those skilled in the art from the description, which includes the detailed description, some of which are included in the accompanying drawings and the claims, or will be recognized by practicing the described embodiments. The drawings are included to provide a further understanding of the embodiments and serve to explain the principles and operations of the claimed subject matter together with the detailed description. However, the embodiments shown in the drawings are illustrative and exemplary in nature and are not intended to limit the claimed subject matter.

Brief Description of the Drawings

[0008] The following detailed description may be better understood when read in conjunction with the following drawings.

Figure 1

Figure 2

[0009] When explaining the simplified schematic diagram of FIG. 1, numerous valves, temperature sensors, electronic controllers, etc. that can be used and are well known to those skilled in the art are not included. Further, accompanying components that are often included within such a reactor system, such as air suppliers, heat exchangers, surge tanks, etc. are also not included. However, it should be understood that these components are within the scope of the present disclosure.

[0010] Here, various embodiments are referred to in more detail, some of which are illustrated in the accompanying drawings.

Mode for Carrying Out the Invention

[0011] The present disclosure is directed to a method for producing light olefins by dehydrogenation in which a combustion additive is utilized. The method generally includes operating a catalytic dehydrogenation process, monitoring the composition of combustion gas in a combustor to detect the concentration of one or more hydrocarbons, and selectively adding a combustion additive together with a catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of a lower flammability level of the combustion gas at the temperature and pressure of the combustor. In the embodiments described herein, the combustion additive includes one or more transition metals excluding gallium and precious metals at 1 wt% - 10 wt%, gallium and precious metals at 0 ppmw - 100 ppmw, and at least 85 wt% of a carrier. According to some embodiments, such a combustion additive may be particularly well-suited for the fluidized dehydrogenation of light alkanes to light olefins, such as propane to propylene, where an auxiliary fuel such as methane is used to heat the catalyst.

[0012] The embodiments disclosed in this specification are described in detail herein in the context of the reactor system of FIG. 1 that operates as a fluidized dehydrogenation reactor system for producing light olefins, such as propylene. However, it should be understood that the principles disclosed and taught herein may be applicable to other systems that utilize different system components oriented in different manners or to different reaction schemes that utilize various catalyst compositions. For example, the concepts described may be equally applicable to other systems with alternative reactor units and regeneration units, such as those that operate under non-fluidized conditions or those that include a downer rather than a riser. Further, it should be understood that not all parts of FIG. 1 should be construed as essential to the claimed subject matter.

[0013] Referring now to FIG. 2, a flowchart showing a method 500 for making light olefins by dehydrogenation, according to one or more embodiments described herein, is shown. Step 502 generally includes operating a catalytic dehydrogenation process, step 504 includes monitoring the composition of combustion gas in a combustor to detect the concentration of one or more hydrocarbons, and step 506 includes selectively adding a combustion additive with the catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of the lower flammability level of the combustion gas at the temperature and pressure of the combustor.

[0014] In one or more embodiments, operating the dehydrogenation process in step 502 generally involves contacting a hydrocarbon-containing feed with a catalyst in a reactor to form an olefin-containing effluent, forming coke on the catalyst in the reactor, and at least partially separating the olefin-containing effluent from the catalyst. Step 502 may further include heating the catalyst by passing the catalyst through a combustor and combusting at least a portion of the coke on the catalyst with an auxiliary fuel containing methane in an amount of 1 mole% or more, and passing the catalyst from the combustor to the reactor such that at least a portion of the catalyst continuously circulates between the reactor and the combustor. Such embodiments are described below in connection with the system of FIG. 1.

[0015] Next, referring to FIG. 1, an exemplary reactor system 102 that may be suitable for use with the methods and / or apparatuses described herein is schematically shown. Reactor system 102 generally includes a plurality of system components such as a reactor section 200 and a catalyst treatment section 300. As used herein when describing, "system components" refers to portions of reactor system 102 such as reactors, separators, transfer lines, combinations thereof, and the like. In the context of FIG. 1 as used herein, reactor section 200 generally refers to the portion of reactor system 102 where a major process reaction (e.g., dehydrogenation) takes place and a product stream is formed. A feed stream enters reactor section 200, is converted into a product stream (containing products and unreacted feed), and exits reactor section 200. Reactor section 200 includes a reactor 202 that may comprise an upstream reactor section 250 and a downstream reactor section 230. According to one or more embodiments, as shown in FIG. 1, reactor section 200 may further comprise a catalyst separation section 210 that serves to separate catalyst from the chemical products formed in reactor 202. Also, as used herein, catalyst treatment section 300 generally refers to the portion of reactor system 102 where the catalyst is processed in some manner, such as by combustion, to improve catalyst activity, e.g., by decoking and / or heating the catalyst. Catalyst treatment section 300 may comprise a combustor 350 and a riser 330 and may further comprise a catalyst separation section 310. In one or more embodiments, catalyst separation section 210 can be in fluid communication with combustor 350 (e.g., via a water distribution tower 426), and catalyst separation section 310 can be in fluid communication with upstream reactor section 250 (e.g., via a water distribution tower 424 and a transfer riser 430).

[0016] Generally, as described herein, in the embodiment shown in FIG. 1, the catalyst is circulated between the reactor section 200 and the catalyst treatment section 300. When referring to "catalyst" herein, they may refer to solid materials that are catalytically active for the desired reaction, or other particulate solids referred to with respect to the system of FIG. 1, such as oxygen carriers that are not necessarily catalytically active but affect the reaction. It should be understood that the terms "catalytic activity" and "catalyst activity" refer to the extent to which a catalyst can catalyze the reaction taking place within the reactor system. The catalyst exiting the reactor section 200 may be a deactivated catalyst. As used herein, "deactivated" may refer to a catalyst that has lower catalytic activity or is at a lower temperature compared to the catalyst entering the reactor section 200. However, a deactivated catalyst may maintain some catalytic activity. The decrease in catalytic activity may be due to contamination by substances such as coke. By reactivation (also sometimes referred to as "regeneration" herein), contaminants such as coke can be removed, the temperature of the catalyst can be increased, or both can be done. In an embodiment, the deactivated catalyst can be reactivated by catalyst reactivation in the catalyst treatment section 300. The deactivated catalyst can be reactivated by, but is not limited to, removing coke by combustion, restoring the catalyst acidity, oxidizing the catalyst, other reactivation processes, or combinations thereof. In some embodiments, the catalyst can be heated during reactivation by the combustion of auxiliary fuels such as methane, ethane, hydrogen, propane, natural gas, or combinations thereof. The reactivated catalyst from the catalyst treatment section 300 is then returned to the reactor section 200.

[0017] In an embodiment, additional fresh catalyst can be added to the reactor system 102 to compensate for the decreased catalytic activity of the catalyst. The catalyst may exhibit decreased catalytic activity due to catalyst loss resulting from wear or performance degradation over time.

[0018] In a non-limiting example, the reactor system 102 described herein can be utilized to produce light olefins from a hydrocarbon-containing feed. According to one or more embodiments, the reaction can be a dehydrogenation reaction. According to such embodiments, the hydrocarbon-containing feed may include one or more of ethane, propane, n-butane, and i-butane. In one or more embodiments, the hydrocarbon-containing feed may include at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of ethane. In additional embodiments, the hydrocarbon-containing feed may include at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of propane. In additional embodiments, the hydrocarbon-containing feed may include at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of n-butane. In additional embodiments, the hydrocarbon-containing feed may include at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of i-butane. In additional embodiments, the hydrocarbon-containing feed may include at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of the total of ethane, propane, n-butane, and i-butane.

[0019] In one or more embodiments, the catalyst may comprise, consist essentially of, or consist of one or more of gallium, indium, or thallium, one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium, and a support. As described herein, "consisting essentially of" refers to a material that contains less than 1 wt% of unlisted materials (i.e., consisting essentially of A and B means that A and B together make up at least 99 wt% of the composition). As described herein, the catalyst can be solid particles suitable for fluidization.

[0020] In one or more embodiments, the catalyst may contain one or more of gallium, indium, or thallium in an amount of 0.05 wt% to 10 wt% based on the total mass of the catalyst. For example, the catalyst may contain one or more of gallium, indium, or thallium in an amount of 0.05 wt% to 0.1 wt%, 0.1 wt% to 0.25 wt%, 0.25 wt% to 0.5 wt%, 0.5 wt% to 0.75 wt%, 0.75 wt% to 1 wt%, 1 wt% to 2 wt%, 2 wt% to 3 wt%, 3 wt% to 4 wt%, 4 wt% to 5 wt%, 5 wt% to 6 wt%, 6 wt% to 7 wt%, 7 wt% to 8 wt%, 8 wt% to 9 wt%, 9 wt% to 10 wt%, or any combination of these ranges. In some embodiments, the catalyst may contain one or more of gallium, indium, or thallium in an amount of 0.05 wt% to 5 wt%, 0.05 wt% to 4 wt%, or 0.05 wt% to 3 wt%. In some embodiments, the catalyst contains only gallium and does not contain indium or thallium, or contains only indium and does not contain gallium or thallium, or contains only thallium and does not contain gallium or indium. It should be understood that the composition ranges describing the amounts of gallium, indium, and thallium represent the ranges of any one of these materials or combinations of these materials. Without being bound by theory, a composition having one or more of gallium, indium, or thallium in an amount less than 0.05 wt% is thought to adversely affect the ability of the catalyst to catalyze the alkane dehydrogenation process by reducing both the percentage of dehydrogenated total alkanes and the percentage of dehydrogenated alkanes that are the intended product. However, a composition having one or more of gallium, indium, or thallium in an amount exceeding 10 wt% is thought not to provide a substantial improvement in the catalytic function of the catalyst but may increase the economic cost of operation.

[0021] In one or more embodiments, the catalyst may contain one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in an amount of 5 ppmw to 1000 ppmw based on the total mass of the catalyst. For example, the catalyst may contain one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in an amount of 5 ppmw to 50 ppmw, 50 ppmw to 100 ppmw, 100 ppmw to 200 ppmw, 200 ppmw to 300 ppmw, 300 ppmw to 400 ppmw, 400 ppmw to 500 ppmw, 500 ppmw to 600 ppmw, 600 ppmw to 700 ppmw, 700 ppmw to 800 ppmw, 800 ppmw to 900 ppmw, 900 ppmw to 1000 ppmw, or a combination of these ranges. In some embodiments, the catalyst may contain one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in an amount of 5 ppmw to 900 ppmw, 5 ppmw to 800 ppmw, 5 ppmw to 600 ppmw, 5 ppmw to 500 ppmw, or 10 ppmw to 400 ppmw. In some embodiments, the catalyst contains only platinum and not palladium, rhodium, iridium, ruthenium, or osmium, only palladium and not platinum, rhodium, iridium, ruthenium, or osmium, only rhodium and not platinum, palladium, iridium, ruthenium, or osmium, only iridium and not platinum, palladium, rhodium, ruthenium, or osmium, only ruthenium and not platinum, palladium, rhodium, iridium, or osmium, only osmium and not platinum, palladium, rhodium, iridium, or ruthenium, or only osmium and not platinum, palladium, rhodium, iridium, or ruthenium. It should be understood that the compositional ranges describing the amounts of platinum, palladium, rhodium, iridium, ruthenium, and osmium represent the ranges of any one of these materials or a combination of these materials.Although not bound by theory, a composition having one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in an amount less than 5 ppmw is thought to adversely affect the ability of a catalyst to catalyze an alkane dehydrogenation process by reducing both the percentage of dehydrogenated total alkanes and the percentage of dehydrogenated alkane that is the intended product.

[0022] As described herein, in one or more embodiments, the catalyst may include a support. The support may include one or more of alumina, silica-containing alumina, zirconia-containing alumina, or titania-containing alumina. The support may be present in an amount of at least 50 wt.%, such as at least 55 wt.%, at least 60 wt.%, at least 65 wt.%, at least 70 wt.%, at least 75 wt.%, at least 80 wt.%, or even at least 85 wt.%, based on the total weight of the catalyst. In some embodiments, the support comprises 95 wt.% or less of the catalyst. Generally, the wt.% of the support may fill the remainder of the total catalyst not specified by other materials.

[0023] In one or more embodiments, the catalyst may optionally include one or more alkali metals, one or more alkaline earth metals, or both, in an amount of 0.01 wt.% to 1 wt.%, based on the total weight of the catalyst. For example, the catalyst may include one or more alkali metals, one or more alkaline earth metals, or both, in an amount of 0.01 wt.% to 0.05 wt.%, 0.05 wt.% to 0.1 wt.%, 0.1 wt.% to 0.2 wt.%, 0.2 wt.% to 0.3 wt.%, 0.3 wt.% to 0.4 wt.%, 0.4 wt.% to 0.5 wt.%, 0.5 wt.% to 0.6 wt.%, 0.6 wt.% to 0.7 wt.%, 0.7 wt.% to 0.8 wt.%, 0.8 wt.% to 0.9 wt.%, 0.9 wt.% to 1 wt.%, or any combination of these ranges. In some embodiments, the catalyst may include one or more alkali metals, one or more alkaline earth metals, or both, in an amount of 0.01 wt.% to 0.75 wt.%, 0.02 wt.% to 0.6 wt.%, 0.03 wt.% to 0.5 wt.%, 0.04 wt.% to 0.4 wt.%, or 0.05 wt.% to 0.3 wt.%.

[0024] In one or more embodiments, the catalyst may include solid fine particles capable of fluidization. In some embodiments, the catalyst may exhibit properties known in the industry as "Geldart A" or "Geldart B" properties. The particle types can be classified as "Group A" or "Group B" according to D. Geldart, Gas Fluidization Technology, John Wiley & Sons (New York, 1986), 34-37, and D. Geldart, "Types of Gas Fluidization," Powder Technol. 7 (1973) 285-292, the disclosures of which are incorporated herein by reference in their entirety.

[0025] It is understood by those skilled in the art that Geldart Group A represents a ventable powder having the following: fluidization in a bubble-free range, high bed expansion, a slow and linear degassing rate, where breakup / recombination bubbles may be dominant, bubble characteristics with a maximum bubble size and a large wake, high levels of solid mixing and gas backmixing assuming equal U-Umf (where U is the velocity of the carrier gas and Umf is the minimum fluidization velocity, typically not necessarily measured in meters per second, m / s, i.e., there is an excess gas velocity), axisymmetric slug characteristics, and no jetting except for very shallow beds.

[0026]

Number

[0027] Group B of Geldart starts to foam at Umf, shows moderate bed expansion, rapid degassing, has no limitation on bubble size, assuming U-Umf is equal, the levels of solid mixing and gas backmixing are moderate, both axisymmetric slugs and asymmetric slugs; and is understood by those skilled in the art to represent "sand-like" powders that jet only in shallow beds. These characteristics tend to improve as the average particle size decreases, but the particle size distribution, and with some uncertainty, the gas pressure, temperature, viscosity, or density do not seem to contribute much to the improvement of the above characteristics. Generally, the particles

[0028]

Number

[0029]

Number

[0030] In one or more embodiments, the catalyst may be prepared by incipient wetness impregnation, also known as dry impregnation or capillary impregnation. For example, such a process is described in Marceau et al., Impregnation and Drying, Synthesis of Solid Catalysts 59 (2008), which is hereby incorporated by reference in its entirety. For example, the support may be impregnated using a nitrate or nitrate amine metal precursor, then dried at a temperature below 200 °C, and then calcined at a temperature below 800 °C to produce the catalyst. For example, in some embodiments, the method of making the catalyst includes impregnating a support with gallium and platinum, drying the support, and calcining the support, and the catalyst comprises 0.05 wt% to 10 wt% gallium, 5 ppmw to 1000 ppmw platinum, and at least 85 wt% support.

[0031] Sequential incipient wetness impregnation allows the support to be impregnated with metals in a sequential order in which some metals may be impregnated onto the support before others. Thus, the order of impregnation can be changed as desired. Further, other suitable methods for making the catalysts described herein are contemplated, as would be known to those skilled in the art.

[0032] As described with respect to FIG. 1, a feed stream may enter the reactor 202 from the feed inlet 434, and a product stream may exit the reactor system 102 via the pipe 420. According to one or more embodiments, the reactor system 102 may operate by feeding a chemical feed (e.g., in the feed stream) and a fluidized catalyst to an upstream reactor section 250. The chemical feed contacts the catalyst within the upstream reactor section 250, and each flows upward into the downstream reactor section 230 and through the downstream reactor section 230 to produce a chemical product.

[0033] Referring now in detail to FIG. 1, the reactor section 200 may include an upstream reactor section 250, a transfer section 258, and a downstream reactor section 230 such as a riser. The transfer section 258 can connect the upstream reactor section 250 to the downstream reactor section 230. As shown in FIG. 1, the upstream reactor section 250 may be disposed below the downstream reactor section 230. Such a configuration can be referred to as an upflow configuration in the reactor 202. The upstream reactor section 250 may include a tank, a drum, a barrel, a vat, or other container suitable for a given chemical reaction. As shown in FIG. 1, the upstream reactor section 250 can be connected to the downstream reactor section 230 via the transfer section 258. The upstream reactor section 250 can generally have a larger cross-sectional area than the downstream reactor section 230. The transfer section 258 may be tapered from the cross-sectional size of the upstream reactor section 250 toward the cross-sectional size of the downstream reactor section 230 such that the transfer section 258 projects inwardly from the upstream reactor section 250 toward the downstream reactor section 230. For example, the transfer section 258 may be a frustum of a cone.

[0034] The upstream reactor section 250 can be connected to a transfer riser 430 that can provide reactivated catalyst in the feed stream to the reactor section 200 during operation. The reactivated catalyst and / or reaction chemicals can be mixed at a distributor 260 housed within the upstream reactor section 250. The catalyst entering the upstream reactor section 250 via the transfer riser 430 can be sent to the transfer riser 430 through a water distribution tower 424 and thus arrives from the catalyst treatment section 300. In some embodiments, the catalyst may enter the transfer riser 430 directly from the catalyst separation section 210 via a standpipe 422, in which case the catalyst enters the upstream reactor section 250 and, in such embodiments, a portion of the catalyst does not pass through the catalyst treatment section 300. The catalyst can also be supplied directly to the upstream reactor section 250 via the standpipe 422 (not shown in FIG. 1). This catalyst may be somewhat deactivated but may still be suitable for reaction within the upstream reactor section 250 in some embodiments, particularly when used in combination with reactivated catalyst.

[0035] Referring further to FIG. 1, in one or more embodiments, based on the shape, size, and other processing conditions (such as temperature and pressure) of the upstream reactor section 250 and the downstream reactor section 230, the upstream reactor section 250 can operate as a fluidized bed such as a fast fluidized bed, a turbulent fluidized bed, or a bubble column riser reactor, while the downstream reactor section 230 can operate in a plug flow mode such as a riser reactor. For example, the reactor 202 of FIG. 1 may include an upstream reactor section 250 that operates as a fast fluidized bed, a turbulent fluidized bed, or a bubble column reactor, and a downstream reactor section 230 that operates as a dilute phase riser reactor, such that the average catalyst and gas flow move upward simultaneously. By "average flow" is meant, when the term is used herein, the net flow, i.e., the flow obtained by subtracting the reverse or countercurrent flow from the total upward flow, as is typical of the behavior of fluidized particles in general. As described herein, a "fast fluidized" reactor can refer to a reactor that utilizes a fluidization regime in which the superficial gas velocity is faster than the choking velocity and can be semi-dense during operation. As described herein, a "turbulent" reactor can refer to a fluidization regime in which the superficial velocity is slower than the choking velocity and the density is higher than that of the fast fluidization regime. As described herein, a "bubble column" reactor can refer to a fluidization regime in which well-defined bubbles in a high-density bed exist in two distinct phases. The "choking velocity" refers to the minimum velocity required to maintain the solid in the dilute phase mode in a vertical transport line. As described herein, a "dilute phase riser" can refer to a riser reactor that operates at a velocity above the flooding velocity.

[0036] According to an embodiment, the chemical product and the catalyst may be discharged from the downstream reactor section 230 and sent to the separation device 220 in the catalyst separation section 210, where the catalyst is separated from the chemical product and the chemical product is transported from the catalyst separation section 210. According to one or more embodiments, following separation from the vapor in the separation device 220, the catalyst may generally move through the stripper 224 to the catalyst outlet port 222, where the catalyst exits the reactor section 200 via the water distribution tower 426 and is transferred to the catalyst treatment section 300.

[0037] According to one or more embodiments, the separation device 220 may be a cyclone separation system that can include two or more stages of cyclone separation. In embodiments where the separation device 220 includes more than one cyclone separation stage, the first separation device into which the fluidized stream enters is referred to as the primary cyclone separation device. The fluid effluent from the primary cyclone separation device can enter a secondary cyclone separation device for further separation. Examples of primary cyclone separation devices can include primary cyclones, as well as systems commercially available under the names VSS (commercially available from UOP), LD2 (commercially available from Stone and Webster), and RS2 (commercially available from Stone and Webster). Primary cyclones are described, for example, in U.S. Patent Nos. 4,579,716, 5,190,650, and 5,275,641, each of which is hereby incorporated by reference in its entirety. In some separation systems that utilize a primary cyclone as the primary cyclone separation device, one or more additional cyclones, such as secondary and tertiary cyclones, are used to further separate the catalyst from the product gas. It should be understood that any primary cyclone type separation device can be used in embodiments of the present invention.

[0038] Referring further to FIG. 1, the separated catalyst moves from the catalyst separation section 210 to the combustor 350. In the combustor 350, the catalyst can be treated, for example, by combustion with oxygen. For example, but not limited to, the catalyst can remove coke and / or burn auxiliary fuel to heat the catalyst. Next, the catalyst exits the combustor 350 and is sent through the riser 330 to the riser end separator 378, where the gas and solid components from the riser 330 are at least partially separated. The vapor and remaining solids are transferred to the secondary separator 320 within the catalyst separation section 310, where the remaining catalyst is separated from the gas from the catalyst treatment (e.g., the gas released by the combustion of the spent catalyst or auxiliary fuel, referred to herein as flue gas). The flue gas can exit the catalyst treatment unit 300 via the outlet pipe 432. Next, the separated catalyst moves through the oxygen treatment zone 370 within the catalyst separation section 310 via the water distribution tower 424 and the transfer riser 430 to the upstream reactor section 250, where it is further utilized for the catalytic reaction. Thus, the catalyst can circulate between the reactor section 200 and the catalyst treatment section 300 during operation. Generally, the treated chemical substance stream, including the feed stream and the product stream, may be gaseous, and the catalyst may be a fluidized particulate solid.

[0039] Here, referring to the catalyst treatment unit 300, as shown in FIG. 1, the combustor 350 of the catalyst treatment unit 300 may include one or more lower reactor section inlet ports 352 and may be in fluid communication with the riser 330. An oxygen-containing gas such as air can move through the pipe 428 to the combustor 350. The combustor 350 can be in fluid communication with the catalyst separation section 210 via the water distribution tower 426, and the water distribution tower 426 can supply the used catalyst from the reactor section 200 to the catalyst treatment unit 300 for regeneration. The combustor 350 and the riser 330, collectively referred to as the catalytic combustion reactor 302, can operate in a fluidization regime similar to or the same as that disclosed for the upstream reactor section 250 and the downstream reactor section 230 of the reactor section 200. That is, the combustor 350 can operate as a fluidized bed in a high-speed fluidized bed, turbulent flow bed, or bubble bed riser reactor, etc., while the riser 330 can operate in a plug flow mode such as a riser reactor. The geometric shapes described for the upstream reactor section 250 and the downstream reactor section 230 can be equally applied to the combustor 350 and the riser 330. Further, the combustor 350 may also include a fuel inlet 354 through which a fuel such as a hydrocarbon stream can be supplied to the combustor 350.

[0040] As described in one or more embodiments, following the separation of the flue gas from the catalyst in the riser end separator 378 and the secondary separator 320, the treatment of the treated catalyst with the oxygen-containing gas is carried out in the oxygen treatment zone 370. In some embodiments, the oxygen treatment zone 370 includes a fluid-solid contact device. The fluid-solid contact device can include a baffle or grid structure for facilitating the contact of the treated catalyst with the oxygen-containing gas. Examples of the fluid-solid contact device are described in more detail in U.S. Patent Nos. 9,827,543 and 9,815,040. The fluidization regime in the oxygen treatment zone may be a bubble bed type fluidization. The oxygen treatment zone 370 can include an oxygen-containing gas inlet 372 through which the oxygen-containing gas can be fed to the oxygen treatment zone 370 for the oxygen treatment of the catalyst.

[0041] In one or more embodiments, the light olefins may be present in a “product stream,” sometimes referred to as an “olefin-containing effluent,” and may include light olefins. Such a stream exits the reactor system of FIG. 1 and may subsequently be processed. As used herein, the term “light olefins” refers to one or more of ethylene, propylene, and butene. The term butene includes any isomers of butene such as α-butylene, cis-β-butylene, trans-β-butylene, and isobutylene. In some embodiments, the olefin-containing effluent comprises at least 20 wt % light olefins, based on the total weight of the olefin-containing effluent. For example, the olefin-containing effluent may comprise at least 25 wt % light olefins, at least 30 wt % light olefins, at least 35 wt % light olefins, at least 40 wt % light olefins, at least 45 wt % light olefins, at least 50 wt % light olefins, at least 55 wt % light olefins, at least 60 wt % light olefins, or at least 65 wt % light olefins, based on the total weight of the olefin-containing effluent. The olefin-containing effluent may further comprise unreacted components of the feed stream, as well as other reaction products that are not considered light olefins. The light olefins can be separated from the unreacted components in a subsequent separation step.

[0042] Referring again to FIG. 2, step 504 generally includes monitoring the composition of the combustion gas in the combustor to detect the concentration of one or more hydrocarbons. The monitoring can be used to detect when the combustion activity in the combustor is below a desired threshold activity. As described herein, “combustion activity” refers to the rate of chemical combustion. Generally, the combustion activity can be monitored by the temperature of the catalyst exiting the combustor. In other embodiments, the combustion activity can be monitored by an on-line analysis of the composition of the flue gas.

[0043] Although not bound by theory, it is believed that several situations can lead to a decrease in combustion activity. In one or more embodiments, the catalytic activity decreases over time, and the combustion catalytic activity decreases more than the dehydrogenation activity. In such embodiments, since the dehydrogenation activity does not decrease to the amount where a fresh catalyst is required and combustion can be improved by the use of a combustion additive, the addition of the combustion additive can enable normal operation without the need to add a fresh catalyst.

[0044] In embodiments, the composition of the auxiliary fuel can be varied, and as a result, the combustion rate of the auxiliary fuel can be varied. For example, methane can burn at a lower rate than other fuels such as hydrogen and propane. In such embodiments, an increase in the amount of the combustion additive within the reactor system can raise the combustion rate to an acceptable level. Further, the combustion additives described herein can provide improved combustion activity for the combustion of methane in some embodiments.

[0045] Referring further to FIG. 2, step 506 generally includes selectively adding a combustion additive with a catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of the lower flammability level of the combustion gas at the temperature and pressure of the combustor. In one or more embodiments, the combustion additive is added to the reactor system 102 when the combustion gas (i.e., the gas generated by combusting a combustion fuel in the combustor 350) contains one or more hydrocarbons (e.g., methane, ethane, and / or propane) in an amount exceeding 5% of the lower flammability limit (LFL) of the combustion gas at the temperature and pressure of the catalytic treatment unit 300 such as the combustor 350. For example, the combustion additive can be added to the reactor system 102 with a catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 10% of the LFL of the combustion gas at the temperature and pressure of the catalytic treatment unit 300. As used in the present disclosure, the term "lower flammability limit" refers to the lower end of the concentration range at which a combustible mixture of a gas or vapor in air can be ignited at a given temperature and pressure. The LFL of the combustion gas can be determined by a reactive chemical test or using pressure adjustment as described in Coward et al., Limits of Flammability of Gases and Vapors, 503 Bureau of Mines 1 (1952), and Michael G. Zabetakis, Flammability Characteristics of Combustible Gases and Vapors, 627 Bureau of Mines 1 (1965).

[0046] In one or more embodiments, the combustion additive can include one or more transition metals. As used herein, the phrase "transition metal" refers to a metal selected from the elements of groups 3 - 12 of the IUPAC. In one or more embodiments, the combustion additive can include manganese, iron, cobalt, tin, or a combination of two or more thereof. In one or more embodiments, the combustion additive can be selected from manganese, iron, cobalt, tin, and combinations of two or more thereof.

[0047] In one or more embodiments, the combustion additive may include from 1 wt% to 10 wt% of gallium and one or more transition metals excluding precious metals, based on the total weight of the combustion additive. For example, the combustion additive may include one or more transition metals excluding gallium and precious metals in an amount of from 1 wt% to 2 wt%, from 1 wt% to 3 wt%, from 1 wt% to 4 wt%, from 1 wt% to 5 wt%, from 1 wt% to 6 wt%, from 1 wt% to 7 wt%, from 1 wt% to 8 wt%, from 1 wt% to 9 wt%, from 1 wt% to 10 wt%, from 2 wt% to 3 wt%, from 2 wt% to 4 wt%, from 2 wt% to 5 wt%, from 2 wt% to 6 wt%, from 2 wt% to 7 wt%, from 2 wt% to 8 wt%, from 2 wt% to 9 wt%, or from 2 wt% to 10 wt%, based on the total weight of the combustion additive. Without intending to be bound by any particular theory, it is believed that a combustion additive having one or more transition metals in an amount less than 1 wt% may require a greater amount of additive to be used in the system to achieve the desired catalytic activity. However, it is believed that a combustion additive having one or more transition metals in an amount greater than 10 wt% may reduce the efficiency of the combustion performance.

[0048] In one or more embodiments, the combustion additive may comprise, consist essentially of, or consist of one or more of manganese, iron, cobalt, or tin in an amount of 1 wt% to 10 wt% based on the total mass of the combustion additive. For example, the combustion additive may comprise one or more of manganese, iron, cobalt, or tin in an amount of 1 wt% to 2 wt%, 1 wt% to 3 wt%, 1 wt% to 4 wt%, 1 wt% to 5 wt%, 1 wt% to 6 wt%, 1 wt% to 7 wt%, 1 wt% to 8 wt%, 1 wt% to 9 wt%, 1 wt% to 10 wt%, 2 wt% to 3 wt%, 2 wt% to 4 wt%, 2 wt% to 5 wt%, 2 wt% to 6 wt%, 2 wt% to 7 wt%, 2 wt% to 8 wt%, 2 wt% to 9 wt%, or 2 wt% to 10 wt% based on the total weight of the combustion additive. In some embodiments, the combustion additive comprises only manganese and does not contain iron, cobalt, or tin, or comprises only iron and does not contain manganese, cobalt, or tin, or comprises only cobalt and does not contain manganese, iron, or tin, or comprises only tin and does not contain manganese, iron, or cobalt. It should be understood that the compositional ranges representing the amounts of manganese, iron, cobalt, and tin represent the ranges of any one of these materials or combinations of these materials.

[0049] In one or more embodiments, the combustion additive may contain less than 100 ppmw of gallium and noble metals based on the total weight of the combustion additive. As used herein, "noble metals" refers to ruthenium, rhodium, palladium, osmium, iridium, platinum, silver, and gold. In one or more embodiments, the combustion additive does not contain gallium and noble metals. In one or more embodiments, the combustion additive may contain gallium and noble metals in an amount of 0 ppmw to 100 ppmw, 0 ppmw to 50 ppmw, 0 ppmw to 25 ppmw, 0 ppmw to 10 ppmw, or 0 ppmw to 5 ppmw based on the total weight of the combustion additive. Without being bound by a particular theory, it is believed that the elimination or reduction of gallium and noble metals in the combustion additive can reduce the economic cost of the dehydrogenation process.

[0050] In one or more embodiments, the combustion additive may include less than 5 wt% of one or more alkali metals, one or more alkaline earth metals, or both, based on the total weight of the combustion additive. For example, the combustion additive may include from 0 wt% to 5 wt%, from 0 wt% to 4 wt%, from 0 wt% to 3 wt%, from 0 wt% to 2 wt%, from 0 wt% to 1 wt%, from 1 wt% to 5 wt%, from 1 wt% to 4 wt%, from 1 wt% to 3 wt%, from 1 wt% to 2 wt%, from 2 wt% to 5 wt%, from 2 wt% to 4 wt%, from 2 wt% to 3 wt%, from 3 wt% to 5 wt%, from 3 wt% to 4 wt%, or from 4 wt% to 5 wt% of one or more alkali metals, one or more alkaline earth metals, or both. Without being bound by a particular theory, it is believed that a combustion additive having an alkali metal, an alkaline earth metal, or both may reduce the secondary reaction of the desired dehydrogenation product. However, it is believed that a combustion additive having more than 5 wt% of an alkali metal, an alkaline earth metal, or both may no longer provide such a function.

[0051] In one or more embodiments, the combustion additive may include a carrier material. Specifically, the combustion additive may include a transition metal, an alkali metal, and / or an alkaline earth metal disposed and / or dispersed on the carrier. In some embodiments, the carrier material includes one or more of alumina, silica, titanium oxide, and zirconium. For example, the carrier material may include one or more of alumina, silica-containing alumina, titanium oxide-containing alumina, and zirconium-containing alumina. The carrier may be present in an amount of at least 85 wt% relative to the total weight of the combustion additive. In some embodiments, the carrier includes 99 wt% or less of the combustion additive. Generally, the wt% of the carrier may fill the remainder of the total combustion additive not specified by other materials.

[0052] In one or more embodiments, the combustion additive may be prepared by incipient wetness impregnation, also known as dry impregnation or capillary impregnation. For example, such a process is described in Marceau et al., Impregnation and Drying, Synthesis of Solid Catalysts 59 (2008), which is hereby incorporated by reference in its entirety. For example, the support may be impregnated using a metal nitrate or amine nitrate precursor, then dried at a temperature below 200 °C, and then calcined at a temperature below 800 °C to produce the combustion additive. For example, in some embodiments, the method of making the combustion additive may include impregnating a support with a transition metal, drying the support, and calcining the support, and the combustion additive may include one or more transition metals excluding gallium and noble metals in an amount of 1 wt% to 10 wt%, gallium and noble metals in an amount of 0 ppmw to 100 ppmw, and at least 85 wt% of the support.

[0053] Incipient wetness sequential impregnation allows the support to be impregnated with metals in a sequential order in which some metals can be impregnated onto the support before others. Thus, the order of impregnation can be changed as desired. In addition, other suitable methods for making the combustion additives described herein are contemplated, as would be known to those of skill in the art.

[0054] In one or more embodiments, the dehydrogenation catalytic activity of the combustion additive may be less than 25% of the dehydrogenation catalytic activity of the catalyst, and the dehydrogenation catalytic activity refers to the percent feed conversion in the propane dehydrogenation test described herein. For example, the dehydrogenation catalytic activity of the combustion additive can be less than 20%, less than 15%, less than 10%, or even less than 5% of the dehydrogenation catalytic activity of the catalyst. In embodiments, the dehydrogenation catalytic activity is the propane dehydrogenation catalytic activity.

[0055] In one or more embodiments, the conversion rate by Approach to Equilibrium (ATE) of the combustion additive can be less than 15% of the conversion rate by ATE of the catalyst, where the conversion rate by ATE refers to the calculation of the conversion rate by Approach to Equilibrium in the test methods described herein. For example, the conversion rate by Approach to Equilibrium (ATE) of the combustion additive can be less than 12%, less than 10%, less than 8%, less than 7%, less than 6%, or even less than 5% of the conversion rate by ATE of the catalyst when measured in the calculation of the conversion rate by Approach to Equilibrium in the test methods described herein.

[0056] In embodiments, when a combustion additive is added with a catalyst, the catalyst can be diluted, thereby potentially reducing the dehydrogenation catalyst activity of the system. However, the wear characteristics of the combustion additive and the catalyst can be controlled to reduce or eliminate this dilution effect. During operation of the catalytic dehydrogenation process, both the catalyst and the combustion additive can be subject to wear. As used herein, the term "attrition" can refer to the undesired mechanical breakage and decomposition of solid materials, such as catalysts and combustion additives, into catalyst fines and smaller particles by attrition and fragmentation mechanisms. Catalyst attrition can result in catalyst loss from the unit because fines having a particle size below a certain threshold, for example, less than 20 microns, may not be retained by the reactor system 102. Combustion additive attrition can result in a decrease in combustion activity. Combustion additive attrition can also reduce the dilution effect on dehydrogenation activity. As the solid wears, the abraded material can be discharged from the reactor system. The attrition characteristics of the catalyst and the combustion additive can affect the lifetimes of the catalyst and the combustion additive in a fluidized bed process, such as the fluidized dehydrogenation reactor described herein. For example, if the combustion additive has a higher attrition rate than the catalyst in commercial operation, the combustion additive may remain in the unit for a shorter period than the catalyst in a fluidized bed process. Attrition evaluation can be performed by various laboratory-scale or pilot-scale attrition tests, such as ASTM D5757, the underwater jet test, and the jet cup attrition test.

[0057] The jet cup attrition index is one of the standard laboratory test methods for characterizing the catalyst attrition characteristics for fluidized bed applications, as described in Cocco et al., Jet Cup Attrition Testing, 200 Powder Technology 224 (2010). Laboratory tests cannot provide the actual attrition rate on a commercial scale unit, but laboratory tests provide a ranking of the attrition tendency. In one or more embodiments, the jet cup attrition index of the combustion additive is greater than the jet cup attrition index of the catalyst, and the jet cup attrition is measured at a threshold of 45 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams. In an embodiment, the jet cup attrition index of the combustion additive is at least 4 times the jet cup attrition index of the catalyst, and the jet cup attrition is measured at a threshold of 45 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample charge of 100 grams. For example, the jet cup attrition index of the combustion additive can be at least 5 times, at least 6 times, or even at least 7 times the jet cup attrition index of the catalyst, and the jet cup attrition is measured at a threshold of 45 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams. In an embodiment, the jet cup attrition index of the combustion additive is greater than the jet cup attrition index of the catalyst, and the jet cup attrition is measured at a threshold of 20 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams. In an embodiment, the jet cup attrition index of the combustion additive is at least 4 times the jet cup attrition index of the catalyst, and the jet cup attrition is measured at a threshold of 20 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams. For example, the jet cup attrition index of the combustion additive can be at least 5 times, at least 6 times, or even at least 7 times the jet cup attrition index of the catalyst, and the jet cup attrition is measured at a threshold of 20 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams.While not bound by any particular theory, it is believed that having a combustion additive jet cup wear index that is less than four times the jet cup wear index of the catalyst can result in dilution and / or deactivation of the catalyst. Conversely, having a combustion additive jet cup wear index that is at least four times greater than the jet cup wear index of the catalyst is believed to enable improved selective removal of the combustion additive from the system. Thus, this difference in wear characteristics between the combustion additive and the catalyst is believed to have the potential to reduce the dilution effect of the catalyst as additional amounts of the combustion additive are added during operation of the reactor system. As used herein, the wear index is measured using the PSRI standard jet cup method using a 3” conical jet cup having an orifice with an inner diameter of 0.1875 inches.

[0058] In one or more embodiments, the amount of combustion additive introduced into the reactor system 102 per addition is from 0.01 volume percent (vol%) to 2 volume percent (vol%) of the total of the volume of the catalyst and the volume of the combustion additive. For example, the amount of combustion additive introduced into the reactor system 102 can be from 0.01 vol% to 1.5 vol%, 0.01 vol% to 1 vol%, 0.01 vol% to 0.5 vol%, 0.05 vol% to 1.5 vol%, 0.05 vol% to 1 vol%, 0.05 vol% to 0.5 vol%, 0.5 vol% to 2 vol%, 0.5 vol% to 1.5 vol%, 0.5 vol% to 1 vol%, 1 vol% to 2 vol%, 1 vol% to 1.5 vol%, or 1.5 vol% to 2 vol% of the total of the volume of the catalyst and the volume of the combustion additive. In an embodiment, the amount of combustion additive introduced into the reactor system 102 can be modified based on monitoring the composition of the combustion gas in the combustor. While not intending to be bound by any particular theory, it is believed that adding the combustion additive with the catalyst in an amount greater than 2 vol% can dilute the catalyst in the reactor system such that the catalytic dehydrogenation activity decreases. Conversely, if the combustion additive is not added with the catalyst when the system lacks combustion activity, a decrease in fuel gas conversion rate may result.

[0059] When introduced into the reactor system 102, the combustion additive is mixed with the catalyst, and as a result, it should be understood that it circulates through the reactor system 102 as previously discussed with respect to the catalyst. In other words, when the combustion additive is introduced into the reactor system 102, a catalyst system that is a mixture of the catalyst and the combustion additive can result. Due to the natural changes in the properties of the catalyst and the combustion additive during the operation of the reactor system 102, the properties and amounts of the combustion additive and / or the catalyst can refer to the properties and amounts of the combustion additive and / or the catalyst at the time of introduction of the combustion additive into the reactor system 102.

[0060] Test Methods The various test methods of the present disclosure are further discussed and referenced in the following examples.

[0061] Propane Dehydrogenation Test The propane dehydrogenation test of a sample containing a catalyst and a combustion additive without additional modification is carried out at ambient pressure in a fixed bed system under simulated reaction and regeneration cycles in the laboratory. This cycle includes a reaction step carried out at a reactor temperature of 625 °C, a reaction time of 60 seconds, and a weight hourly space velocity (WHSV) of propane of 10 h−1. The WHSV is defined as the weight of the feed flowing per unit weight of the sample per hour, and the composition of the gas feed boot is 90 volume % (vol %) propane and 10 volume % N2. After the reaction step is completed, the sample undergoes a regeneration step, where the sample is heated in air at 730 °C for 5 minutes. The reaction and regeneration cycles are alternately repeated for a total of 10 cycles. In each reaction step, gas chromatography (GC) is used to analyze the reaction effluent at the 15-second point during operation. The feed conversion rate and the product selectivity are determined by equations (1) and (2), -1 wherein,

[0062]

Equation

[0063] Calculation of conversion rate by approach to equilibrium The conversion rate by approach to equilibrium (%ATE) can be calculated using Equation 3. The conversion rate by approach to equilibrium is the ratio of the feed conversion rate measured by Equation 1 to the equilibrium conversion rate:

[0064]

Equation

[0065] Fuel gas combustion evaluation The fuel gas combustion test of the sample containing the catalyst and combustion additive without additional modification is 0.59 hours. -1 、Performed in a fixed bed laboratory reactor at ambient pressure using WHSV CH4, which is defined as the weight of methane in the feed flowing per unit weight of the sample per hour. The sample (0.1 g of catalyst or combustion additive mixed with 0.1 g of SiC diluent) is heated to 730 °C under a stream of N2. Subsequently, N2 is replaced with a stream of air and helium, where helium constitutes 1.2 vol% of the feed. After 20 minutes, methane is introduced until the feed gas contains 2 vol% methane and 1.2 vol% helium, with the remainder being synthetic air. These test conditions are more severe than commercial operation to allow for a greater distinction in combustion performance. GC samples are continuously taken from the outlet and the feed gas and analyzed to determine the methane conversion. The methane conversion percentage is calculated using Equation 4 at the 3-hour point during operation:

[0066] [Number] where C refers to the concentration of the compound (CO, CO2, or CH4) in the effluent stream.

[0067] Jet cup abrasion test The abrasion evaluation of the catalyst support and combustion additive support is carried out using a 3-inch jet cup abrasion unit designed and fabricated by Particulate Solid Research, Inc (PSRI). The abrasion index derived from the jet cup abrasion test is used to define the abrasion of the support material. Due to the low metal loading of the catalyst and combustion additive, there is no difference (within the test error) in the abrasion index between the support material and the catalyst and combustion additive made therefrom. Therefore, the abrasion of the catalyst support material represents the abrasion of the catalyst and combustion additive containing the support material described herein. The jet cup used in the test is a 3-inch conical jet cup with an orifice having an inner diameter of 0.1875 inches. The test is carried out at ambient temperature, a jet speed of 300 ft / sec, a flow rate of 98 L / min, a sample load of 100 grams, and an abrasion duration of 6 hours. The particle size distribution of the material before and after the abrasion test is characterized using laser diffraction techniques (Beckman Coulter LS13 320). The absolute percentage increase in particles <20 μm and <45 μm (“fine powder”) is reported as the abrasion index (A.I.). A.I.(20 μm) and A.I.(45 μm), which are shown in Equations 5 and 6 respectively. A.I.(20 μm) = (% fine powder <20 μm after test) - (% fine powder <20 μm before test) (5); A.I.(45 μm) = (% fine powder <45 μm after test) - (% fine powder <45 μm before test) (6)

Example

[0068] Various embodiments of the present disclosure are further clarified by the following examples. The examples are illustrative in nature and should not be understood as limiting the subject matter of the present application.

[0069] The catalysts and combustion additives in the examples contain a specified amount of metal, with an average particle size in the range of 5 - 300 μm, a pore volume of 0.35 ± 0.20 mL / g, and 100 ± 50 m 2It was prepared by the conventional incipient wetness impregnation method for loading the indicated amount of metal onto an alumina support containing microspherical silica having a surface area of / g, a silica content of 2.5 ± 2.5 wt%, and various abrasion characteristics. The low-abrasion support material is called the base support, while two materials, support A and support B, have higher abrasion (see Example 4). The metal precursors used are nitrates or amine nitrates. The resulting materials were dried at a temperature below 200 °C and then calcined at a temperature below 800 °C. The base support was used for the preparation of the catalyst, while support A and support B were used for the preparation of the combustion additive.

[0070] Example 1. Combustion additive containing manganese. The combustion additive of Example 1 contained manganese and did not contain platinum or gallium. The specific support materials and compositions for each sample are listed in Table 1. The propane conversion rate %, equilibrium approach (ATE) conversion rate %, propylene selectivity %, and methane conversion rate % were measured according to the test methods described herein and reported in Table 1.

[0071]

Table 1

[0072] As can be seen in Table 1, the combustion additive of Example 1 showed improved combustion activity as indicated by a higher methane conversion rate % compared to the catalyst of Comparative Example A. Furthermore, by increasing the weight % of manganese in the combustion additive from 1 wt% (Example 1-1) to 2.5 wt% (Example 1-3), the combustion activity of the combustion additive was further improved.

[0073] However, some of these combustion additives can hardly provide dehydrogenation activity. Therefore, when such combustion additives accumulate in the catalyst system, a dilution effect may occur. The carrier materials (Carrier A and Carrier B) selected for these additives have higher abrasion than the catalysts of Example A (base carrier) and Example B (base carrier). Therefore, the combustion additives can be selectively removed in the operation of the fluidized bed catalyst in order to reduce or eliminate the dilution effect.

[0074] Example 2. Combustion Additive Containing Iron The combustion additive of Example 2 contained iron and did not contain platinum or gallium. The specific carrier materials and compositions for each sample are listed in Table 2. The propane conversion rate %, conversion rate % based on approach to equilibrium (ATE), propylene selectivity %, and methane conversion rate % were measured according to the test methods described herein and reported in Table 2.

[0075] [Table 2]

[0076] As shown in Table 2, the combustion additive of Example 2 showed improved combustion activity as indicated by a higher methane conversion rate % compared to the catalyst of Comparative Example A. Furthermore, by increasing the weight % of iron in the combustion additive from 1 wt% (Example 2-1) to 2.5 wt% (Example 2-3), the combustion activity of the combustion additive was further improved.

[0077] Similar to the combustion additive of Example 1, the combustion additive of Example 2 reduces dehydrogenation activity. Therefore, high-abrasion carrier materials are selected for these additives (Carrier A and Carrier B), so that they can be selectively removed in the operation of the fluidized bed catalyst to reduce the dilution effect on dehydrogenation performance.

[0078] Example 3. Combustion Additive Containing Cobalt or Tin The combustion additive of Example 3 contained cobalt or tin and did not contain platinum or gallium. The specific carrier materials and compositions for each sample are listed in Table 3. The propane conversion rate %, the conversion rate % by approach to equilibrium (ATE), the propylene selectivity %, and the methane conversion rate % were measured according to the test methods described herein and reported in Table 3.

[0079]

Table 3

[0080] As can be seen in Table 3, the combustion additive of Example 3 showed improved combustion activity as indicated by a higher methane conversion rate % compared to the catalyst of Comparative Example A. Similar to the combustion additives of Example 1 and Example 2, the combustion additive of Example 3 reduces dehydrogenation properties. Therefore, a high wear carrier material was selected for these additives (Carrier A and Carrier B), so that they can be selectively removed in a fluidized bed catalyst operation to reduce the dilution effect on dehydrogenation performance.

[0081] Comparative Example A. Catalyst containing platinum and gallium The catalyst of Comparative Example A contained platinum and gallium and did not contain manganese. The specific carrier materials and compositions for each sample are listed in Table 4. The propane conversion rate %, the conversion rate % by approach to equilibrium (ATE), the propylene selectivity %, and the methane conversion rate % were measured according to the test methods described herein and reported in Table 4. In an embodiment, these catalysts can be used to provide good dehydrogenation performance.

[0082]

Table 4

[0083] As can be seen in Table 4, the catalysts containing platinum and gallium (Example A-1 and Example A-2) showed lower combustion activity as indicated by a lower methane conversion rate % compared to the combustion additives of Examples 1 to 3.

[0084] Comparative Example B. Combustion Additive Containing Manganese The catalyst of Comparative Example B contained manganese and did not contain platinum or gallium. The specific carrier materials and compositions for each sample are listed in Table 5. The propane conversion rate %, the conversion rate % based on the approach to equilibrium (ATE), the propylene selectivity %, and the methane conversion rate % were measured according to the test methods described herein and reported in Table 5.

[0085]

Table 5

[0086] As can be seen in Table 5, the catalyst containing 0.15 wt% manganese in the absence of platinum and gallium (Example B-1) showed lower combustion activity as indicated by a lower methane conversion rate % compared to the combustion additive of Example 1. When the manganese concentration was increased to 1 wt%, a significant improvement in combustion performance was observed (Example B-2). The dehydrogenation performance of the catalysts of Comparative Example B was low in the absence of platinum and gallium. However, in contrast to the combustion additives of Examples 1 to 3, the carrier materials (base carriers) selected for these catalysts would have a catalyst abrasion rate similar to that of Example A. Since the dehydrogenation performance of Comparative Example B is low, such catalysts can cause a dilution effect when they accumulate in the catalyst system, despite their increased combustion activity compared to Comparative Example A.

[0087] Example 4. Abrasion Test Wear of the carrier material was measured using the jet cup wear test as described herein. The results of A.I. (20 μm) and A.I. (45 μm) of the carrier material are shown in Table 6. A.I. represents the absolute difference in the percentage of fines having a particle size below a certain threshold before and after the jet cup wear test, as described herein. For example, an A.I. of 3.7 (20 μm) indicates that the absolute percentage of fines having a particle size below 20 μm increased by 3.7% after the wear test, while an A.I. of 5.1 (45 μm) indicates that the raw percentage of fines having a particle size below 45 μm increased by 5.1% after a 6-hour wear period for the base carrier. For Carrier A, the absolute percentage of fines having a particle size below 20 μm increased by 23.9% after the wear test, while the absolute percentage of fines having a particle size below 45 μm increased by 39.9% under the same conditions as the base carrier wear test.

[0088]

Table 6

[0089] As shown in Table 6, the A.I. results indicate that the wear rate of Carrier A or the combustion additive is greater than 700% of the wear rate of the base carrier or catalyst under the standard PSRI test described herein. In other words, the unit time to mechanical wear of the combustion additive containing either Carrier A or Carrier B is expected to be shorter than that of the catalyst containing the base carrier in the reactor system.

[0090] A first aspect of the present disclosure is a method for producing light olefins by dehydrogenation, the method comprising operating a catalytic dehydrogenation process, monitoring the composition of combustion gas in a combustor to detect the concentration of one or more hydrocarbons, and selectively adding a combustion additive together with a catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of a lower flammability level of the combustion gas at the temperature and pressure of the combustor. Operating includes contacting a hydrocarbon-containing feed with a catalyst in a reactor to form an olefin-containing effluent, at least partially separating the olefin-containing effluent from the catalyst, passing the catalyst through a combustor and heating the catalyst by burning an auxiliary fuel containing methane in an amount of 1 mol% or more, and passing the catalyst from the combustor to the reactor such that at least a portion of the catalyst continuously circulates between the reactor and the combustor. The jet cup abrasion index of the combustion additive is greater than the jet cup abrasion index of the catalyst, and the jet cup abrasion is measured at a threshold of 45 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams. The combustion additive includes one or more transition metals excluding gallium and precious metals in an amount of 1 wt% to 10 wt%, gallium and precious metals in an amount of 0 parts per million by weight (ppmw) to 100 ppmw, and at least 85 wt% of a carrier.

[0091] A second aspect of the present disclosure may include the first aspect, wherein the one or more transition metals are selected from manganese, iron, cobalt, tin, or combinations thereof.

[0092] A third aspect of the present disclosure may include any one of the second or third aspects, wherein the combustion additive includes 1 wt% to 10 wt% of manganese.

[0093] A fourth aspect of the present disclosure may include any one of the first to third aspects, wherein the combustion additive includes 1 wt% to 10 wt% of iron.

[0094] The fifth aspect of the present disclosure may include any one of the first to fourth aspects, where the combustion additive contains 1 wt% to 10 wt% of cobalt.

[0095] The sixth aspect of the present disclosure may include any one of the first to fifth aspects, where the combustion additive contains 1 wt% to 10 wt% of tin.

[0096] The seventh aspect of the present disclosure may include any one of the first to sixth aspects, where the combustion additive further contains 0.01 wt% to 5 wt% of one or more alkali metals or alkaline earth metals.

[0097] The eighth aspect of the present disclosure may include any one of the first to seventh aspects, where the jet cup wear index of the combustion additive is at least 4 times that of the catalyst.

[0098] The ninth aspect of the present disclosure may include any one of the first to eighth aspects, where the dehydrogenation catalytic activity of the combustion additive is less than 25 percent of that of the catalyst.

[0099] The tenth aspect of the present disclosure may include any one of the first to ninth aspects, where the hydrocarbon-containing feed contains one or more of ethane, propane, n-butane, or i-butane, and the olefin-containing effluent contains one or more of ethylene, propylene, and butylene.

[0100] The eleventh aspect of the present disclosure may include any one of the first to tenth aspects, where the olefin-containing effluent contains at least 20 wt% of light olefins.

[0101] The twelfth aspect of the present disclosure may include any one of the first to eleventh aspects, where the hydrocarbon-containing feed contains propane and the olefin-containing effluent contains propylene.

[0102] The 13th aspect of the present disclosure may include any one of the 1st to 12th aspects, where the auxiliary fuel further includes natural gas, ethane, propane, hydrogen, or a combination of two or more thereof.

[0103] The 14th aspect of the present disclosure may include any one of the 1st to 13th aspects, where the catalyst includes at least one metal selected from 0.05 wt% to 10 wt% of gallium, indium, thallium, or a combination thereof, at least one metal selected from 5 ppmw to 1000 ppmw of platinum, palladium, rhodium, iridium, ruthenium, osmium, or a combination thereof, and at least 85 wt% of a carrier.

[0104] The 15th aspect of the present disclosure may include any one of the 1st to 14th aspects, where the catalyst includes 0.05 wt% to 10 wt% of gallium, 5 ppmw to 1000 ppmw of platinum, and at least 85 wt% of a carrier.

[0105] It will be apparent to those skilled in the art that various modifications and changes can be made to the technology of the present disclosure without departing from the spirit and scope of the technology. Combinations, sub - combinations, and variations of modifications of the disclosed embodiments incorporating the spirit and substance of the technology of the present disclosure can be conceived by those skilled in the art, so the technology should be construed to include all within the scope of the appended claims and their equivalents. Further, although some aspects of the present disclosure may be specified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not limited to these aspects.

[0106] It should be noted that the various details described in this disclosure should not be construed as implying that these details are related to elements that are essential components of the various embodiments described in this disclosure, even if a particular element is illustrated in each of the accompanying drawings. Unless specifically so specified, the features disclosed and described herein should not be construed as "essential". The contemplated embodiments of the present technology include those that include some or all of the features of the appended claims.

[0107] For the purposes of describing and defining this disclosure, it should be noted that the term "about" is utilized in this disclosure to represent the degree of inherent uncertainty that may arise from any quantitative comparison, value, measurement, or other representation. The term "about" is also utilized in this disclosure to represent the degree to which a quantitative representation may vary from the reference of the description without causing a change in the basic function of the subject matter in question.

[0108] When relevant, when a composition is described as "comprising" one or more elements, embodiments of the composition "consisting of" or "consisting essentially of" those one or more elements are contemplated herein.

[0109] It should be understood that in some embodiments, the composition ranges of the chemical components in a stream or reactor are understood to contain mixtures of isomers of those components. For example, a composition range specifying butene may include mixtures of the various isomers of butene. It should be understood that the examples supply various composition ranges of streams and that the total amount of isomers of a particular chemical composition may constitute the range.

[0110] It should be noted that in one or more of the following claims, the terms "where" or "wherein" are used as transitional phrases. For the purpose of defining the present technology, this term is introduced into the claims as a non-limiting transitional phrase used to introduce a list of a series of features of the structure and should be construed in the same manner as the more commonly used non-limiting preamble term "comprising".

[0111] It should be understood that any two quantitative values assigned to a property can constitute a range of that property, and all combinations of ranges formed from all the described quantitative values of a given property are contemplated in the present disclosure. If multiple ranges are given for a quantitative value, these ranges may be combined to form a broader range, which is contemplated in the embodiments described herein.

Claims

Claim 1 A method for producing light olefins by dehydrogenation, comprising: operating a catalytic dehydrogenation process, wherein said operating comprises: contacting a hydrocarbon-containing feed with a catalyst in a reactor to form an olefin-containing effluent; at least partially separating the olefin-containing effluent from the catalyst; passing the catalyst through a combustor and heating the catalyst by combusting an auxiliary fuel, wherein the auxiliary fuel contains methane in an amount of 1 mol% or more; passing the catalyst from the combustor to the reactor such that at least a portion of the catalyst continuously circulates between the reactor and the combustor; monitoring the composition of the combustion gas in the combustor to detect the concentration of one or more hydrocarbons; selectively adding a combustion additive together with the catalyst when the combustion gas contains one or more hydrocarbons in an amount exceeding 5% of a lower flammability level of the combustion gas at the temperature and pressure of the combustor, wherein the jet cup wear index of the combustion additive is greater than the jet cup wear index of the catalyst, and the jet cup wear is measured at a threshold of 45 μm after 6 hours at ambient temperature, a jet velocity of 300 ft / sec, a flow rate of 98 L / min, and a sample load of 100 grams, and the combustion additive comprises: 1 wt% to 10 wt% of one or more of transition metals and noble metals excluding tin or gallium; 0 weight parts per million (ppmw) to 100 ppmw of gallium and noble metals; and at least 85 wt% of a carrier. Claim 2 The method according to claim 1, wherein the one or more transition metals are selected from manganese, iron, cobalt, or combinations thereof. Claim 3 The method according to any of the preceding claims, wherein the combustion additive contains 1 wt% to 10 wt% of manganese. Claim 4 The method according to any of the preceding claims, wherein the combustion additive contains 1 wt% to 10 wt% of iron. Claim 5 The method according to any of the preceding claims, wherein the combustion additive contains 1 wt% to 10 wt% of cobalt. Claim 6 The method according to any of the preceding claims, wherein the combustion additive contains 1 wt% to 10 wt% of tin. Claim 7 The method according to any of the preceding claims, wherein the combustion additive further contains 0.01 wt% to 5 wt% of one or more alkali metals or alkaline earth metals. Claim 8 The method according to any of the preceding claims, wherein the jet cup wear index of the combustion additive is at least four times the jet cup wear index of the catalyst. **Claim 9** The method according to any of the preceding claims, wherein the dehydrogenation catalytic activity of the combustion additive is less than 25 percent of the dehydrogenation catalytic activity of the catalyst. **Claim 10** The method according to any of the preceding claims, wherein the hydrocarbon-containing feed comprises one or more of ethane, propane, n-butane, or i-butane, and the olefin-containing effluent comprises one or more of ethylene, propylene, and butylene. **Claim 11** The method according to any of the preceding claims, wherein the olefin-containing effluent comprises at least 20 weight percent light olefins. **Claim 12** The method according to any of the preceding claims, wherein the hydrocarbon-containing feed comprises propane and the olefin-containing effluent comprises propylene. **Claim 13** The method according to any of the preceding claims, wherein the auxiliary fuel further comprises natural gas, ethane, propane, hydrogen, or a combination of two or more thereof. **Claim 14** The catalyst is one or more metals selected from 0.05 weight percent to 10 weight percent of gallium, indium, thallium, or a combination thereof, one or more metals selected from 5 ppmw to 1000 ppmw of platinum, palladium, rhodium, iridium, ruthenium, osmium, or a combination thereof, and at least 85 weight percent of a carrier, according to any of the preceding claims. **Claim 15** The catalyst is 0.05 weight percent to 10 weight percent of gallium, 5 ppmw to 1000 ppmw of platinum; and at least 85 weight percent of a carrier, according to any of the preceding claims.

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