Methods for operating olefinic material production systems utilizing passivation agents passed through gas distributors

Abstract

An olefinic material production system may be started by a method that includes raising the temperature of the combustor of the olefinic material production system from a first temperature that is less than 100 °C to a second temperature range of from 600 °C to 900 °C, circulating a particulate solid between the combustor and a reactor, and passing a first stream into the combustor through a gas distributor. The first stream may include a passivation agent in a first concentration. The passivation agent may include one or more of a sulfur-containing compound, a nitrogen-containing compound, a hydroxide moiety-containing compound excluding water, or a phosphorous-containing compound. The method may further include, following the passing of the first stream into the combustor through the gas distributor, passing a second stream into the combustor through the gas distributor. The second stream that may be present inside the gas distributor and that may be passed into the combustor may include the passivation agent in a second concentration, wherein the first concentration is greater than the second concentration, and a supplemental fuel including at least 0.01 mol.% of one or more olefins.

Description

METHODS FOR OPERATING OLEFINIC MATERIAL PRODUCTION SYSTEMS UTILIZING PASSIVATION AGENTS PASSED THROUGH GAS DISTRIBUTORSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 665,031 filed June 27, 2024, the contents of which are incorporated in their entirety herein.TECHNICAL FIELD

[0002] Embodiments of the present disclosure generally relate to chemical processes and, in particular, to methods and systems for making olefinic materials.BACKGROUND

[0003] Olefinic materials, such as ethylene, butene, propylene, and styrene, may be used as base materials to produce many different materials, such as polyethylene, polypropylene, isopropanol, and acrylic acid, which may be used in, e.g., packaging, construction, and textiles. As a result of this utility, there is a worldwide demand for olefinic materials. However, methods for efficiently producing such olefinic materials are challenging, and improvements in technology for such purposes are desired by industry.SUMMARY

[0004] The present disclosure is directed to methods for operating olefinic material production systems, particularly at the start-up of the systems prior to olefinic material production. As is described herein, a passivation agent may be passed through a gas distributor and into a combustor of an olefinic material production system in a first stream followed by a second stream, where the first steam has a greater concentration of passivation agent than the second stream. According to some embodiments, and without being bound by any particular theory, it is believed that the first stream that includes the greater concentration of passivation agents may form a passivation layer on the gas distributor and the second stream having the lesser concentration of passivation agents may substantially maintain the passivation layer. The passivation layer may mitigate coking on the gas distributor, which may form from supplemental fuel that is passed through the gas distributor, where such coking may partially or fully block passage of the supplemental fuel into the combustor through the gas distributor.

[0005] According to one or more embodiments, an olefinic material production system may be started by a method that comprises raising the temperature of the combustor of the olefinic material production system from a first temperature that is less than 100 °C to a second temperature range of from 600 °C to 900 °C, circulating a particulate solid between the combustor and a reactor, and passing a first stream into the combustor through a gas distributor. The first stream may comprise a passivation agent in a first concentration. The passivation agent may comprise one or more of a sulfur-containing compound, a nitrogen-containing compound, a hydroxide moiety-containing compound excluding water, or a phosphorous-containing compound. The method may further comprise, following the passing of the first stream into the combustor through the gas distributor, passing a second stream into the combustor through the gas distributor. The second stream that may be present inside the gas distributor and that may be passed into the combustor may comprise the passivation agent in a second concentration, wherein the first concentration is greater than the second concentration, and a supplemental fuel comprising at least 0.01 mol.% of one or more olefins.

[0006] It is to be understood that both the preceding general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. Additional features and advantages of the embodiments will be set forth in the detailed description and, in part, will be readily apparent to persons of ordinary skill in the art from that description, which includes the accompanying drawing and claims, or recognized by practicing the described embodiments. The drawing is included to provide a further understanding of the embodiments and, together with the detailed description, serves to explain the principles and operations of the claimed subject matter. However, the embodiment depicted in the drawing is illustrative and exemplary in nature, and not intended to limit the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The following detailed description may be better understood when read in conjunction with the following drawing, in which:

[0008] FIG. 1 schematically depicts a olefinic material production system, according to one or more embodiments of the present disclosure; and

[0009] FIG. 2 schematically depicts a combustor of an olefinic material production system, according to one or more embodiments of the present disclosure.

[0010] When describing the simplified schematic illustration of FIGS. 1 and 2, the numerous valves, temperature sensors, electronic controllers, and the like, which may be used and are well known to a person of ordinary skill in the art, are not included. Further, accompanying components that are often included in such reactor systems, such as air supplies, heat exchangers, surge tanks, and the like are also not included. However, it should be understood that these components are within the scope of the present disclosure.

[0011] Reference will now be made in greater detail to various embodiments, some of which are illustrated in the accompanying drawing.DETAILED DESCRIPTION

[0012] Olefinic materials may be produced in olefinic material production systems that operate by circulating particulate solids, such as catalysts, between a reactor, where olefins are produced from paraffins, and a combustor, where the particulate solids are heated. As is described in detail herein, during start-up, the olefin material production system may have the temperature in the combustor raised to at or near operational temperatures and the solid particulate may be circulated between the reactor and the combustor, each prior to normal olefinic material production mode where olefinic materials are produced by dehydrogenation. To maintain needed temperatures in the combustor, a supplemental fuel may be utilized, which is passed through a gas distributor into the combustor. Some such supplemental fuels may include olefins or other compounds that have a propensity for coking, especially when in contact with metal surface such as stainless steel. Surprisingly, it has been found that even when olefins are present in the supplemental fuel in relatively small amounts, coking may take place on the gas distributor, which may clog the gas distributor and inhibit steady-state operation of the olefinic material production system.

[0013] As described herein, it has been discovered that utilizing a passivation agent during start-up can diminish coking on the gas distributor. In such embodiments, the passivation agent, such as a sulfur-containing compound, may be passed through the gas distributor in a first stream that has a relatively high concentration of passivation agent, followed by a second stream thatincludes supplemental fuel as well as relatively low concentration of passivation agent as compared with the first stream. Without being bound by theory, it is believed that the first stream may form a passivation layer over the gas distributor surface, and the second stream may maintain the passivation layer. According to embodiments, the first stream may optionally include the supplemental fuel, whereas the second stream includes the supplemental fuel that includes components susceptible to coking that can clog the gas distributor. The second stream may be maintained throughout normal olefinic material production operation, where the lower amounts of passivation agent may not drastically affect activity of the particulate solid while maintaining the passivation layer on the gas distributor. Again, without being bound by theory, the presence of the passivation layer may diminish coking, which may promote steady-state operation of the olefinic material production system during normal operation where olefinic materials are produced.

[0014] As described herein, an olefinic material production system is any system that can produce olefinic materials. As described herein, olefinic materials refer to compounds that include at least one alkene moiety (i.e., a C=C double bond). In some embodiments, the olefinic materials may be “light olefins” such as ethylene, propylene, butene, or styrene. These olefinic materials can be produced via dehydrogenation from ethane, propane, butane, and ethylbenzene, respectively, which may be included as the feed into the reactor.

[0015] According to embodiments described herein, and as is described in detail herein, particulate solids may be utilized in the process to form olefinic materials, whereby the particulate solids continuously circulate between a reactor and a combustor during normal steady-state operation during olefinic material production. The olefinic materials are produced in the reactor, and the particulate solids are heated in the combustor by combustion of a supplemental fuel. Various reaction mechanisms, and associated reactants, may be utilized to form the olefinic materials. For example, dehydrogenation may be utilized to convert paraffins to olefins, such as ethane to ethylene, butane to butylene, and propane to propylene, or to convert ethylbenzene to styrene. Such dehydrogenation reactions may utilize a catalyst, which may be the solid particulate. In additional embodiments, olefinic materials may be produced by cracking reactions, dehydration reactions, and methanol-to-olefin reactions. These reaction types may utilize different hydrocarbon feed streams and different catalytic particulate solids to produce the olefinic materials from hydrocarbon feeds. In additional embodiments, it is contemplated that theparticulate solids may be non-catalytic solids such as, for example, materials capable of carrying oxygen (referred to sometimes herein as “oxygen carrier materials”). For example, such oxygen carrier materials may be utilized along with catalyst whereby hydrogen produced in a dehydrogenation reactor is combusted by contact with oxygen supplied from the oxygen carrier materials. In additional embodiments, oxygen carrier materials may be utilized without catalyst, where thermal dehydrogenation may form hydrogen that is combusted by contact with the oxygen from the oxygen carrier materials.

[0016] Embodiments of the methods presently disclosed are described in detail herein in the context of the olefinic material production system 100 of FIG. 1 operating as a fluidized dehydrogenation reactor system to produce olefinic materials, such as propylene. However, it should be understood that the principles disclosed and taught herein may be applicable to other systems which utilize different system components oriented in different ways. For example, the concepts described herein may be equally applied to other systems with alternate reactor units and regeneration units, such as those that operate under non-fluidized conditions or include downers rather than risers. It should be further understood that not all portions of FIG. 1 should be construed as essential to the claimed subject matter. Moreover, while the recited method steps in the appended claims are described herein in the context of FIG. 1, such recited method steps should be understood as adaptable to other systems, as would be understood by those skilled in the art.

[0017] Referring to FIG. 1, an olefinic material production system 100 is schematically depicted. Methods for starting the olefinic material production system 100 will be best understood following explanation of the olefinic material production system 100 during normal olefinic material production mode (sometimes referred to as steady-state operation, herein). Thus, initially described herein is the operation of the olefinic material production system 100 at steady-state conditions where olefinic materials are being produced by catalytic dehydrogenation utilizing a catalyst as the particulate solid.

[0018] Still referring to FIG. 1, an example olefinic material production system 100 that may be suitable for use with the methods and / or apparatuses described herein is schematically depicted. The olefinic material production system 100 generally comprises multiple system components that are included in a reactor portion 200 and a catalyst processing portion 300. As described herein, “system components” refer to portions of the olefinic material production system100, such as reactors, separators, transfer lines, combinations thereof, and the like. As used herein in the context of FIG. 1, the reactor portion 200 generally refers to the portion of the olefinic material production system 100 in which the major process reaction takes place (e.g., dehydrogenation) to form an olefinic material-containing effluent. A hydrocarbon-containing feed enters the reactor portion 200, is contacted with a catalyst, converted to an olefinic materialcontaining effluent (containing product and unreacted feed), and exits the reactor portion 200. The reactor portion 200 comprises a reactor 202 which may include an upstream reactor section 250 and a downstream reactor section 230. According to one or more embodiments, as depicted in FIG. 1, the reactor portion 200 may additionally include a catalyst separation section 210, which serves to separate the catalyst from the olefinic material-containing effluent formed in the reactor 202. Also, as used herein, the catalyst processing portion 300 generally refers to the portion of the olefinic material production system 100 where the catalyst is in some way processed, such as by combustion, to, e.g., improve catalytic activity by decoking and / or heating the catalyst. The catalyst processing portion 300 may comprise a combustor 350 and a riser 330, and may additionally comprise a catalyst separation section 310. In one or more embodiments, the catalyst separation section 210 may be in fluid communication with the combustor 350 (e.g., via standpipe 426) and the catalyst separation section 310 may be in fluid communication with the upstream reactor section 250 (e.g., via standpipe 424 and transport riser 430).

[0019] Generally as is described herein, in embodiments illustrated in FIG. 1, catalyst is circulated between the reactor portion 200 and the catalyst processing portion 300. It should be understood that when “catalysts” are referred to herein, they may refer to solid materials that are catalytically active for a desired reaction. The terms “catalytic activity” and “catalyst activity” refer to the degree to which the catalyst is able to catalyze the reactions conducted in the olefinic material production system 100. The catalyst that exits the reactor portion 200 may be deactivated catalyst. As used herein, “deactivated” may refer to a catalyst which has reduced catalytic activity or is cooler as compared to catalyst entering the reactor portion 200. However, deactivated catalyst may maintain some catalytic activity. Reduced catalytic activity may result from contamination with a substance such as coke. Coke may form on the catalyst within the reactor portion 200. Reactivation (sometimes called “regeneration” herein) may remove the contaminant such as coke, raise the temperature of the catalyst, or both. In embodiments, deactivated catalyst may be reactivated by catalyst reactivation in the catalyst processing portion 300. The deactivated catalystmay be reactivated by, but not limited to, removing coke by combustion, oxidizing the catalyst, other reactivation process, or combinations thereof. In some embodiments, the catalyst may be heated during reactivation by combustion of a supplemental fuel, such as hydrogen, methane, ethane, propane, natural gas, or combinations thereof. The reactivated catalyst from the catalyst processing portion 300 is then passed back to the reactor portion 200. The catalyst is heated during regeneration to aid with regeneration and also because heated catalyst serves as a heat carrier to carry heat from the combustor 350 to the reactor portion 200 to facilitate the dehydrogenation reaction.

[0020] In non-limiting examples, the olefinic material production system 100 described herein may be utilized to produce light olefins from a hydrocarbon-containing feed. According to one or more embodiments, the reaction may be a dehydrogenation reaction. According to such embodiments, the hydrocarbon-containing feed may comprise one or more of ethane, propane, butane, and ethylbenzene. In one or more embodiments, the hydrocarbon-containing feed may comprise 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 one or more embodiments, the hydrocarbon- containing feed may comprise 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 ethylbenzene. In additional embodiments, the hydrocarbon-containing feed may comprise 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 comprise 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, i-butane, or combinations thereof.

[0021] 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 materials with less than 1 wt.% of the non-recited materials (i.e., consisting essentially of A and B means A and B combined are at least 99 wt.% of the composition). In additional 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; a support; and one or both of alkali or alkaline earth metals. As is described herein, the catalyst may be solid particles suitable for fluidization.

[0022] Still referring to FIG. 1, the hydrocarbon-containing feed may enter feed inlet 434 into the reactor 202, and the olefinic material-containing effluent may exit the olefinic material production system 100 via pipe 420. According to one or more embodiments, the olefinic material production system 100 may be operated by feeding a hydrocarbon-containing feed (e.g., in a feed stream) and a fluidized catalyst into the upstream reactor section 250. The hydrocarbon-containing feed contacts the catalyst in the upstream reactor section 250, and each flow upwardly into and through the downstream reactor section 230 to produce an olefin-containing effluent. The reactor 202 may operate at relatively high temperatures, such as from 500 °C to 800 °C (e.g., from 500 °C to 550 °C, from 550 °C to 600 °C, from 600 °C to 650 °C, from 650 °C to 700 °C, from 700 °C to 750 °C, from 750 °C to 800 °C, or any combination of one or more of these ranges).

[0023] Now referring to FIG. 1 in detail, the reactor portion 200 may comprise an upstream reactor section 250, a transition section 258, and a downstream reactor section 230, such as a riser. The transition section 258 may connect the upstream reactor section 250 with the downstream reactor section 230. As depicted in FIG. 1, the upstream reactor section 250 may be positioned below the downstream reactor section 230. Such a configuration may be referred to as an upflow configuration in the reactor 202. The upstream reactor section 250 may include a vessel, drum, barrel, vat, or other container suitable for a given chemical reaction. As depicted in FIG. 1, the upstream reactor section 250 may be connected to the downstream reactor section 230 via the transition section 258. The upstream reactor section 250 may generally comprise a greater cross- sectional area than the downstream reactor section 230. The transition section 258 may be tapered from the size of the cross-section of the upstream reactor section 250 to the size of the crosssection of the downstream reactor section 230 such that the transition section 258 projects inwardly from the upstream reactor section 250 to the downstream reactor section 230. For example, the transition section 258 may be a frustum.

[0024] The upstream reactor section 250 may be connected to a transport riser 430, which, in operation may provide reactivated catalyst in a feed stream to the reactor portion 200. The reactivated catalyst and / or reactant chemicals may be mixed with a distributor 260 housed in the upstream reactor section 250. The catalyst entering the upstream reactor section 250 via transport riser 430 may be passed through standpipe 424 to a transport riser 430, thus arriving from the catalyst processing portion 300. In some embodiments, catalyst may come directly from the catalyst separation section 210 via standpipe 422 and into a transport riser 430, where it enters theupstream reactor section 250, where in such embodiments some of the catalyst is not passed through the catalyst processing portion 300. The catalyst can also be fed via standpipe 422 directly to the upstream reactor section 250 (not depicted in FIG. 1). This catalyst may be somewhat deactivated, but may still, in some embodiments, be suitable for reaction in the upstream reactor section 250, particularly when used in combination with reactivated catalyst.

[0025] In one or more embodiments, the catalyst may have a residence time within the reactor portion 200 of less than or equal to 5 minutes. As the term is used herein, “residence time” refers to the average amount of time the catalyst or other specified material spends within the reactor portion 200 in contact with the feed (e.g., time from first contact with feed to time of separation from product). As it is an average, the amount of time the catalyst may spend within the reactor portion 200 during any given cycle may not be equal to the average, but over time will average out to be equal to about the residence time. In some embodiments, the catalyst may have a residence time within the reactor portion 200 of less than or equal to 4.5 min., less than or equal to 4 min., less than or equal to 3.5 min., less than or equal to 3 min., less than or equal to 2.5 min., less than or equal to 2 min., less than or equal to 1.5 min., less than or equal to 1 min., less than or equal to 0.5, or less than or equal to 0.1 min. Without being bound by theory, it is believed that catalyst residence time greater than 3 minutes may increase equipment costs without a matching increase in catalyst dehydrogenation performance. However, it is believed that catalyst residence time less than 0.1 minutes may not allow the catalyst to sufficiently catalyze the dehydrogenation reaction.

[0026] Still referring to FIG. 1, in one or more embodiments, based on the shape, size, and other processing conditions (such as temperature and pressure) in the upstream reactor section 250 and the downstream reactor section 230, the upstream reactor section 250 may operate as a fluidized bed, such as in a fast fluidized, turbulent, or bubbling bed upflow reactor, while the downstream reactor section 230 may operate in more of a plug flow manner, such as in a riser reactor. For example, the reactor 202 of FIG. 1 may comprise an upstream reactor section 250 operating as a fast fluidized, turbulent, or bubbling bed reactor and a downstream reactor section 230 operating as a dilute phase riser reactor, with the result that the average catalyst and gas flow moves concurrently upward. As the term is used herein, “average flow” refers to the net flow, i.e., the total upward flow minus the retrograde or reverse flow, as is typical of the behavior of fluidized particles in general. As described herein, a “fast fluidized” reactor may referto a reactor utilizing a fluidization regime wherein the superficial velocity of the gas phase is greater than the choking velocity and may be semi-dense in operation. As described herein, a “turbulent” reactor may refer to a fluidization regime where the superficial velocity of less than the choking velocity and is more dense than the fast fluidized regime. As described herein, a “bubbling bed” reactor may refer to a fluidization regime wherein well defined bubbles in a highly dense bed are present in two distinct phases. The “choking velocity” refers to the minimum velocity required to maintain solids in the dilute-phase mode in a vertical conveying line. As described herein, a “dilute phase riser” may refer to a riser reactor operating at above choking velocity.

[0027] According to embodiments, the olefinic material-containing effluent and the catalyst may be passed out of the downstream reactor section 230 to a separation device 220 in the catalyst separation section 210, where the catalyst is at least partially separated from the olefin- containing effluent, which is transported out of the catalyst separation section 210. According to one or more embodiments, following separation from vapors in the separation device 220, the catalyst may generally move through the stripper 224 to the catalyst outlet port 222 where the catalyst is transferred out of the reactor portion 200 via standpipe 426 and into the catalyst processing portion 300.

[0028] According to one or more embodiments, the separation device 220 may be a cyclonic separation system, which may include two or more stages of cyclonic separation. In embodiments where the separation device 220 comprises more than one cyclonic separation stages, the first separation device into which the fluidized stream enters is referred to a primary cyclonic separation device. The fluidized effluent from the primary cyclonic separation device may enter into a secondary cyclonic separation device for further separation. Primary cyclonic separation devices may include, for example, primary cyclones, and systems commercially available under the names VSS (commercially available from UOP), TD2 (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, which are each incorporated by reference in their entirety herein. In some separation systems utilizing primary cyclones as the primary cyclonic separation device, one or more set of additional cyclones, e.g. secondary cyclones and tertiary cyclones, are employed for further separation of thecatalyst from the product gas. It should be understood that any primary cyclonic separation device may be used in embodiments of the present disclosure.

[0029] Still referring to FIG. 1 , the separated catalyst is passed from the catalyst separation section 210 to the combustor 350. In some embodiments, the catalyst may be exposed to another oxy gen-containing gas, such as air, downstream of the reactor 202 and upstream of the combustor 350, such as in a standpipe leading to the combustor 350. Such oxygen exposure may serve to oxidize the catalyst prior to combustion, which may improve combustion catalytic functionality.

[0030] In the combustor 350, the catalyst may be processed by, for example, combustion of coke with oxygen (if coke is present) and with combustion of supplemental fuel. For example, and without limitation, the catalyst may be de-coked and / or supplemental fuel may be combusted to heat the catalyst. The catalyst is then passed out of the combustor 350 and through the riser 330 to a riser termination separator 378, where the gas and solid components from the riser 330 are at least partially separated. The vapor and remaining solids are transported to a secondary separation device 320 in the catalyst separation section 310 where the remaining catalyst is separated from the gases from the catalyst processing (e.g., gases emitted by combustion of spent catalyst or supplemental fuel, referred to herein as flue gas). The flue gas may pass out of the catalyst processing portion 300 via outlet pipe 432. The separated catalyst is then passed through the oxygen treatment zone 370 within the catalyst separation section 310 to the upstream reactor section 250 via standpipe 424 and transport riser 430, where it is further utilized in a catalytic reaction. Thus, the catalyst, in operation, may cycle between the reactor portion 200 and the catalyst processing portion 300. In general, the processed chemical streams, including the hydrocarbon-containing feed and olefinic material-containing effluent may be gaseous, and the catalyst may be fluidized particulate solid.

[0031] Referring now to the catalyst processing portion 300, as depicted in FIG. 1, the combustor 350 of the catalyst processing portion 300 may include one or more lower reactor portion inlet ports 352 and may be in fluid communication with the riser 330. Oxygen-containing gas, such as air, may be passed through pipe 428 into the combustor 350. In general, the oxygencontaining gas may comprise at least 10 mol.% oxygen. The combustor 350 may be in fluid communication with the catalyst separation section 210 via standpipe 426, which may supply spent catalyst from the reactor portion 200 to the catalyst processing portion 300 for regeneration.The combustor 350 and riser 330, collectively referred to as the catalyst combustion reactor 302, may operate with similar or identical fluidization regimes as to what was disclosed with respect to the upstream reactor section 250 and downstream reactor section 230 of the reactor portion 200. That is, the combustor 350 may operate as a fluidized bed, such as in a fast fluidized, turbulent, or bubbling bed upflow reactor, while the riser 330 may operate in more of a plug flow manner, such as in a riser reactor. Geometries as described with respect to the upstream reactor section 250 and downstream reactor section 230 may equally apply to the combustor 350 and riser 330. Additionally, the combustor 350 may also include a fuel inlet 354, which may supply a fuel, such as a hydrocarbon stream, to the combustor 350.

[0032] Still referring to olefinic material operation mode in steady state, as described herein, the catalyst may be heated in the catalyst processing portion 300 by combustion of supplemental fuels. Supplemental fuels may combust with oxygen to heat the catalyst, and supplemental fuels such as a supplemental fuel, such as hydrogen, methane, ethane, propane, natural gas, or combinations thereof.

[0033] Now referring to FIG. 2, one embodiment of a combustor 350 suitable with the system and methods of FIG. 1 is schematically depicted. As shown in FIG. 1, the combustor 350 may comprise a vessel 360 whereby catalyst may enter the vessel 360 through downcomer 362. Alternatively or additionally, in embodiments, the catalyst may enter the vessel 102 from a side inlet (not shown) or from a bottom feed (not shown), passing upward through the air distributor 364. The catalyst may impinge upon and may be distributed by a splash guard. The combustor 350 may include the air distributor 364, which may be a plate distributor and may be located at or slightly below the height of the splash guard. Above the air distributor 364 and the outlet of the downcomer 362 may be one or more grids 366. The girds may operate as bubble breakers to promote even fluidization within the combustor 350.

[0034] Still referring to FIG. 1, the combustor 350 may also include a plurality of gas distributors 368 through which the supplemental fuel is fed into the combustor 350, which may be in fluid communication with the fuel inlet 354. Additionally, liquid fuel used for system startup may be fed through inlet 380.

[0035] Turning back to FIG. 1, as described in one or more embodiments, following separation of flue gas from catalyst in the riser termination separator 378 and secondary separationdevice 320, treatment of the processed catalyst with an oxygen-containing gas, such as air, is conducted in the oxygen treatment zone 370. In general, the oxy gen-containing gas in the oxygen treatment zone 370 may comprise at least 10 mol.% oxygen, and is substantially void of combustable gaseous hydrocarbons that are present in the combustor 350. In some embodiments, the oxygen treatment zone 370 includes a fluid solids contacting device. The fluid solids contacting device may include baffles or grid structures to facilitate contact of the processed catalyst with the oxy gen-containing gas. Examples of fluid solid contacting devices are described in further detail in U.S. Patent Nos. 9,827,543 and 9,815,040. The fluidization regime within the oxygen treatment zone may be bubbling bed type fluidization. The oxygen treatment zone 370 may include an oxygen-containing gas inlet 372, which may supply an oxygen-containing gas to the oxygen treatment zone 370 for oxygen treatment of the catalyst.

[0036] As is disclosed herein, in one or more embodiments the catalyst may be exposed to an oxy gen-containing gas in oxygen treatment zone 370. For example, the catalyst may be exposed to an oxygen-containing gas for from 2 min. to 20 min., such as from 2 min. to 4 min., from 4 min. to 6 min., from 6 min. to 8 min., from 8 min. to 10 min., from 10 min. to 12 min., from 12 min. to 14 min., from 14 min. to 16 min., from 16 min. to 18 min., from 18 min. to 20 min., or any combination of these ranges. In some embodiments the catalyst may be exposed to an oxygen containing gas from 4 min. to 18 min., from 6 min. to 17 min., from 8 min. to 16 min., or from 10 min. to 15 min. Without being bound by theory, it is believed that exposure of the catalyst to an oxygen-containing gas for more than 20 minutes may increase equipment costs without a matching increase in catalyst regeneration efficiency. However, it is believed that oxygen-containing gas exposure for less than 2 minutes may lead to less efficient regeneration of the catalyst which may reduce the catalyst’s dehydrogenation activity. In one or more embodiments, the catalyst may be exposed to the oxygen-containing gas at a temperature of at least 650 °C, such as from 650 °C to 800 °C.

[0037] In one or more embodiments, the olefinic material may be present in a “product stream” sometimes called an “olefin product-containing effluent” and include light olefins. Such a stream exits the olefinic material production system 100 of FIG. 1 and may be subsequently processed.

[0038] As described, the above description, in general, applies to the operation of the olefinic material production system 100 at steady state while olefinic materials are being produced (i.e., not at start-up). Now described herein is a method for starting up the olefinic material production system 100.

[0039] As is described herein, in general, to start-up the reactor, the temperature of the combustor may be raised and particulate solid (e.g., catalyst) may be circulated between the combustor 350 and the reactor 202. It should be understood that solid particulate may be passed into the olefinic material production system 100 and circulated between the combustor 350 and the reactor 202 initially prior to heating of the combustor 350, during heating of the combustor 350, or after the combustor 350 is at or near operational temperature.

[0040] According to one or more embodiments, during system start-up, the temperature in the combustor may be raised from less than 100 °C (e.g., ambient temperature or environmental temperatures of about 25 °C) to a second temperature range of from 600 °C to 900 °C (temperatures at or near those utilized in steady state operation of the olefinic material production system 100). To initially raise the temperature in the combustor 350, a liquid fuel may be combusted in the combustor 350 of the olefinic material production system 100. According to some embodiments, the liquid fuel may be any liquid fuel that has an autoignition temperature of less than 400 °C, such as kerosene. In further embodiments, the liquid fuel may be torch oil, which may include or consist of kerosene. Without being limited by theory, raising the temperature of the combustor 350 from the first temperature range to the second temperature range may allow for safe combustion of supplemental fuel, the composition of which is described in detail herein. According to some embodiments, raising the temperature of the combustor 350 up to at least 600 °C from less that 100 °C may not be safely achievable through combustion of supplemental fuel alone, which is gaseous.

[0041] According to embodiments, the first temperature range may be from 0 °C to 10 °C, from 10 °C to 20 °C, from 20 °C to 30 °C, from 30 °C to 40 °C, from 40 °C to 50 °C, from 50 °C to 60 °C, from 60 °C to 70 °C, from 70 °C to 80 °C, from 80 °C to 90 °C, from 90 °C to 100 °C, or any combination of one or more of these ranges. In one or more embodiments, the second temperature range may be from 600 °C to 625 °C, from 625 °C to 650 °C, from 650 °C to 675 °C, from 675 °C to 700 °C, from 700 °C to 725 °C, from 725 °C to 750 °C, from 750 °C to 775 °C,from 775 °C to 800 °C, from 800 °C to 825 °C, from 825 °C to 850 °C, from 850 °C to 875 °C, from 875 °C to 900 °C, or any combination of one or more of these ranges.

[0042] According to one or more embodiments, a catalyst may be circulated between the combustor 350 and the reactor 202 of the olefinic material production system 100. In one or more embodiments, the catalyst may be a catalyst as described hereinabove. In one or more embodiments, the combusting a liquid fuel in the combustor 350 to raise the temperature of the combustor 350 and the circulating a catalyst between the combustor 350 and the reactor 202 may occur in any order. For example, and in some embodiments, the catalyst may first be circulated between the combustor 350 and the reactor 202, and second, the liquid fuel may be combusted in the combustor 350 to raise the temperature of the combustor 350. Or, for example, the liquid fuel may first be combusted in the combustor 350 to raise the temperature of the combustor 350, and second, the catalyst may be circulated between the combustor 350 and the reactor 202. In some embodiments, these two steps may occur simultaneously.

[0043] Following initial heat up and circulating of the catalyst, according to one or more embodiments, a first stream and second stream, each containing a passivation agent, may be sequentially passed through the gas distributor 368 and into the combustor 350. That is, the first stream is passed into the combustor 350 prior to the passing of the second stream into the combustor 350. As is described in detail herein, the first stream has a greater concentration of passivation agent than the second stream.

[0044] As described herein, a “passivation agent” is any one or more chemical compounds that can form a passivation layer over a surface, which reduces propensity for coking. Without be bound by any particular theory, in general, passivation refers to coating a material so that it becomes "passive", that is, less readily affected by the environment. Passivation involves creation of an outer layer of shield material that is applied as a microcoating, created by chemical reaction with the base material, or allowed to build by spontaneous oxidation in the air. A wide variety of passivation agents are contemplated for use as described herein, where the material upon which the passivation layer is to be formed is important in selecting the passivation agent. As described herein, a passivation agent may include a mixture of multiple chemical compounds.

[0045] According to one or more embodiments, the passivation agent may comprise, consist essentially of, or consist of one or more sulfur-containing compounds (i.e., any chemicalcompound that includes at least one sulfur atom). In additional embodiments, the passivation agent may comprise, consist essentially of, or consist of one or more phosphorus-containing compounds (i.e., any chemical compound that includes at least one phosphorus atom). In additional embodiments, the passivation agent may comprise, consist essentially of, or consist of one or more hydroxide moiety-containing compounds excluding water (i.e., any chemical compound that includes at least one hydroxide moiety, exclusive of water). According to additional embodiments, the passivation agent may comprise, consist essentially of, or consist of one or more nitrogencontaining compounds (i.e., any chemical compound that includes at least one nitrogen atom). In additional embodiments, the passivation agent may comprise, consist essentially of, or consist of mixtures of any combination of sulfur-containing compounds, phosphorus-containing compounds, hydroxide moiety-containing compounds excluding water, and nitrogen-containing compounds.

[0046] According to embodiments, without limitation, sulfur-containing compounds may be chosen from compounds that include H2S or those that can decompose to H2S. For example, contemplated sulfur-containing compounds include methyl mercaptan, dimethylsulfide (DMS), dimethyl disulfide (DMDS), dipropyldisulphides, dibutyldisulphides, ditertbutyldisulphide (DTBDS), diphenyldisulphide (DPDS), carbon disulphide, benzothiophenes, bibenzyl sulphide, phosphorothioate, methanedithione, methyldisulfanyl, methaylsulfanyl, and dimethyl sulfoxides. Without limitation, phosphorus-containing compounds may be chosen from triphenyl phosphite or triethyl phosphite (TEP), triphenyl phosphine (TPP), tri-o-tolylphosphine (TTP), and triphenyl phosphine oxide (TPPO), benzyl diethyl phosphite (BDP), and phosphine. Without limitation, hydroxide moiety-containing compounds may be chosen from ethanol, butanol, glycerol, ethylene glycol, 1,2 propanediol, 1,3 propanediol. 1,2 cyclopentanediol, and 1,2 cyclohexanediol Additionally, without limitation, nitrogen-containing compounds may be chosen from ammonia, methayl amine, ethyl amine, butyl amine, dimethyl amine, diethyl amine, dibutyl amine, trimethyl amine, triethyl amine, tributyl amine, piperidine, N-methylpiperidine, and N-phenylpiperidine.

[0047] As described herein, the first stream may have a greater concentration of passivation agent than the second stream. According to one or more embodiments, the first stream may comprise from 15 ppmw to 100 ppmw of the passivation agent, and the second stream may comprise from 1 ppmw to 12 ppmw of passivation agent. As described herein, the concentration of the passivation agent in the first stream and second stream is a measurement of averageconcentration over time. For example, a passivation agent may be pulsed into the carrier of the first stream or second stream where the concentration of passivation agent would be greater during the pulsing time. Without being bound by theory, the amount of passivation agent in the first stream (e.g., from 15-100 ppmw) is sufficient to form a passivation layer at least on the gas distributor, but low enough such that an excess of passivation agent does not need to enter the system, which may be absorbed by the catalyst (potentially causing deactivation). The amount of passivation agent in the second stream (e.g., from 1-12 ppmw) is great enough such that the passivation layer can be maintained but an excess of passivation agent is not passed into the system. For example, this may be an amount that does not build up on the catalyst as to negatively affect catalytic activity.

[0048] In one or more embodiments, the first stream may include supplemental fuel, or may include only inert carrier gases (or gases that are not susceptible to combustion). For example, the first stream may include the air or nitrogen, or steam, along with the passivation agent. The second stream may generally include the supplemental fuel along with the passivation agent. As described herein, the supplemental fuel (particularly any olefin including in the supplemental fuel) may have a propensity for coking when contacted with metal such as stainless steel. Without being bound by theory, it is believed that the greater concentration of passivation agent present first stream forms the passivation layer and mitigates coking since the passivation layer is formed prior to or simultaneously with supplemental fuel being passed through the gas distributor 368. Then, the relatively small amount of passivation agent present in the second stream can maintain the passivation layer without utilizing so much passivation agent that the catalyst loses activity. In some embodiments, the second stream is utilized during normal olefinic material production mode, where so little passivation agent is included that it is naturally removed from the system 100 or does not substantially affect catalyst performance.

[0049] According to some embodiments, the first stream comprise may from at least 20 ppmw, at least 30 ppmw, at least 40 ppmw, at least 50 ppmw, at least 60 ppmw, at least 70 ppmw, at least 80 ppmw, or even at least 90 ppmw. The second stream may comprise less than or equal to 11 ppmw, less than or equal to 10 ppmw, less than or equal to 9 ppmw, less than or equal to 8 ppmw, less than or equal to 7 ppmw, less than or equal to 6 ppmw, from 1 ppmw to 5 ppmw of passivation agent, less than or equal to 4 ppmw, less than or equal to 3 ppmw, or even less than or equal to 2 ppmw.

[0050] In one or more embodiments, the supplemental fuel that is present in the gas distributor 368 and passed through the gas distributor into the combustor 350 may be any gaseous fuel mixture that can safely combust in the combustor 350. In some embodiments, the supplemental fuel that passes into the gas distributor 368 may comprise at least 0.01 mol.% of one or more olefins, for example light olefins such as propylene, ethylene, and / or butylene. In additional embodiments, the supplemental fuel that passes into the gas distributor 368 may not comprise at least 0.01 mol.% of one or more olefins, for example light olefins such as propylene, ethylene, and / or butylene, in which case the one or more olefins may be formed within the gas distributor 368 by dehydrogenation of an alkane that is present in the supplemental fuel that enters the gas distributor 368. The presence of such olefins may cause coking at or near the gas distributor 368. For example, the supplemental fuel may comprise olefins in an amount of from 0.01 mol.% to 0.2 mol.%, from 0.2 mol.% to 0.4 mol.%, from 0.4 mol.% to 0.6 mol.%, from 0.6 mol.% to 0.8 mol.%, from 0.8 mol.% to 1 mol.%, from 1 mol.% to 1.2 mol.%, from 1.2 mol.% to 1.4 mol.%, from 1.4 mol.% to 1.6 mol.%, from 1.6 mol.% to 1.8 mol.%, from 1.8 mol.% to 2 mol.%, or any combination of one or more of these ranges.

[0051] In some embodiments, the supplemental fuel may comprise at least 90 mol.% of a combination of one or more of hydrogen, methane, ethane, propane, or nitrogen; and from 0.01 mol.% to 2 mol.% of olefins. For example, the supplemental fuel may comprise a combination of hydrogen, methane, and nitrogen in an amount of at least 91 mol.%, at least 92 mol.%, at least 93 mol.%, at least 94 mol.%, at least 95 mol.%, at least 96 mol.%, at least 97 mol.%, at least 98 mol.%, or even at least 99 mol.%. In some embodiments, the supplemental fuel may comprise from 5 mol.% to 40 mol.% of methane and from 60 mol.% to 95 mol.% of hydrogen. Such supplemental fuel streams may be available as an off-gas from a demethanizer from a steam cracking system, which may be co-run with the system 100. In additional embodiments, off-gas from a separate dehydrogenation plant (ethylene, propylene or butene plants) may be utilized as a supplemental fuel. Such streams, sourced from these or other sources, may also be used, according to some embodiments, as the supplemental fuel, as described herein.

[0052] According to additional embodiments, the supplemental fuel may be natural gas (which can include olefins in amounts of at least 0.01 mol.%, causing coking). Natural gas may comprise primarily methane, such as in amounts of at least 75 mol.%, at least 90 mol.%, or at least95 mol.%. In some embodiments, alkanes in the natural gas may thermally dehydrogenate within the gas distributor 368 to form olefins.

[0053] According to some embodiments, prior to passing the first stream into the combustor 350 through the gas distributor 368, passing steam into the combustor 350 through the gas distributor 368. Without being bound by theory, the steam may act to passivate the surface of the gas distributor 368. However, such passivation by steam may not be sufficient to mitigate coking, and may be used as a pretreatment before the passivation agent is utilized.

[0054] Still referring to FIG. 1, according to one or more embodiments, the system 100 may be run in normal olefinic material operation mode following the passing of the first stream and second stream into the combustor 350. During normal operation, the second stream may continue (i.e., the passivation agent may be utilized in relatively low concentrations during operation), or no passivation agent may be utilized.

[0055] Numerous technical aspects are presently disclosed, some of which are specifically described hereinbelow as Aspects 1-15.

[0056] Aspect 1. A method for starting an olefinic material production system, the method comprising: raising the temperature of the combustor of the olefinic material production system from a first temperature that is less than 100 °C to a second temperature range of from 600 °C to 900 °C; circulating a particulate solid between the combustor and a reactor; passing a first stream into the combustor through a gas distributor, wherein the first stream comprises a passivation agent in a first concentration, and wherein the passivation agent comprises one or more of a sulfur- containing compound, a nitrogen-containing compound, a hydroxide moiety-containing compound excluding water, or a phosphorous-containing compound; and following the passing of the first stream into the combustor through the gas distributor, passing a second stream into the combustor through the gas distributor, wherein the second stream present inside the gas distributor and passed into the combustor comprises: the passivation agent in a second concentration, wherein the first concentration is greater than the second concentration; and a supplemental fuel comprising at least 0.01 mol.% of one or more olefins.

[0057] Aspect 2. The method of aspect 1, wherein the passivation agent comprises the sulfur-containing compound chosen from hydrogen sulfide, methyl mercaptan, dimethylsulfide(DMS), dimethyl disulfide (DMDS), dipropyldisulphides, dibutyldisulphides, ditertbutyldisulphide (DTBDS), diphenyldisulphide (DPDS), carbon disulphide, benzothiophenes, bibenzyl sulphide, phosphorothioate, methanedithione, methyldisulfanyl, methaylsulfanyl, and dimethyl sulfoxides.

[0058] Aspect 3. The method of any previous aspect, wherein the gas distributor comprises stainless steel.

[0059] Aspect 4. The method of any previous aspect, wherein the first stream comprises from 15 ppmw to 100 ppmw of the passivation agent, and wherein the second stream comprises from 1 ppmw to 12 ppmw of the passivation agent.

[0060] Aspect 5. The method of any previous aspect, wherein the first stream further comprises the supplemental fuel.

[0061] Aspect 6. The method of any previous aspect, wherein passing the first stream into the combustor through the gas distributor forms a passivation layer on a surface of the gas distributor that mitigates coking.

[0062] Aspect 7. The method of any previous aspect, wherein passing the second stream into the combustor through the gas distributor maintains the passivation layer on the surface of the gas distributor.

[0063] Aspect 8. The method of any previous aspect, wherein the supplemental fuel present in the gas distributor and passed into the combustor comprises: at least 90 mol.% of a combination of one or more of hydrogen, methane, ethane, propane, or nitrogen; and from 0.01 mol.% to 2 mol.% of olefins.

[0064] Aspect 9. The method of any previous aspect, wherein the supplemental fuel comprises from 5 mol.% to 40 mol.% of methane and from 60 mol.% to 95 mol.% of hydrogen.

[0065] Aspect 10. The method of any previous aspect, wherein: the supplemental fuel is an off-gas from a demethanizer from a stream cracking system; the supplemental fuel is natural gas; or the supplemental fuel is from a separate dehydrogenation plant.

[0066] Aspect 11. The method of any previous aspect, further comprising, prior to passing the first stream into the combustor through the gas distributor, passing steam into the combustor through the gas distributor.

[0067] Aspect 12. The method of any previous aspect, further comprising passing a hydrocarbon feed into the reactor to produce olefinic material.

[0068] Aspect 13. The method of any previous aspect, wherein raising the temperature of the combustor from a first temperature range of from 0 °C to 100 °C to a second temperature range of from 600 °C to 900 °C comprises combusting a liquid fuel in the combustor, and wherein the liquid fuel comprises a liquid fuel having an autoignition temperature of less than 400 °C.

[0069] Aspect 14. The method of any previous aspect, wherein the olefinic material production system produces propylene by catalytic dehydrogenation.

[0070] Aspect 15. The method of any previous aspect, wherein the one or more olefins of the second stream present inside the gas distributor and passed into the combustor are: formed in the gas distributor by dehydrogenation of an alkane; or present in the supplemental fuel when passed into the gas distributor.

[0071]

[0072] The following example is illustrative of technical concepts associated with the one or more embodiments disclosed herein, and are not to be construed as limiting on the appended claims.

[0073] Tab testing was carried out to measure the coking growth rate on metal surface at 700 °C using a gas stream with composition simulating steam cracker off gas (2 mol.% ethylene, 80 mol.% H2, 18 mol.% CH4). Different levels of methyl mercaptan (0-30 ppmv) were added to investigate the impact of S addition. The feed stream was introduced to a 60 inch long 304H stainless steel tube, which was coiled up inside a box furnace with temperature controlled at that of the target. In some examples, the 304H stainless steel coil was used as is, in which metal oxide layer was formed during the manufacturing process. In other examples, the coil was first reduced by H2 and then passivated by air by (1) pre-reduction: pretreatment at 800 °C under 100% H2 for 8 hours, and then cooled down to room temperature under inert gas He; and (2) passivation:heating up to 500 °C under He before holding at this temperature for 5 hours under 100% air. The pre-reduction and air passivation was intended to destroy the original metal oxide layer from manufacturing and condition the coil so the surface is more close to that of the working condition where coils experience reduction and decoking routinely.

[0074] The gas stream with composition of interest was fed continuously to the coil at the targeted temperature for a desired time on stream (5 to 50 hours) for the whole coking process. Then the coke was burned off using 5 mol.% oxygen. During the decoking process, the product gas was sent to a mass spectrometer for analysis. The measured CO and CO2 concentrations in the product gas during the decoking process were used to back calculate the amount of coke that was formed. The coke growth rate was then calculated based on the total coke amount, the surface area of the internal tube and the time on stream for the coking process.

[0075] liable § , below, shows the results of coke rate as measured as described herein. Coke growth rate for 0 pprnv of sulfur additive is shown as a raw value, representing 100% in each data set, and additional sulfur additive induced coke growth rates as a percentage of the 100% without sulfur. As is shown the passivation layer can be best built up when sulfur additive of at least 1 ppm is utilized.Table 1:

[0076] For the purposes of describing and defining the present disclosure it is noted that the term “about” are utilized in this disclosure to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The term “about” are also utilized in this disclosure to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. Additionally, the term “consisting essentially of’ is used in this disclosure to refer to quantitative values that do not materially affect the basic and novelcharacteristic(s) of the disclosure. For example, a chemical stream “consisting essentially” of a particular chemical constituent or group of chemical constituents should be understood to mean that the stream includes at least about 99.5% of a that particular chemical constituent or group of chemical constituents.

[0077] It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

[0078] It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure. It should be appreciated that compositional ranges of a chemical constituent in a stream or in a reactor should be appreciated as containing, in some embodiments, a mixture of isomers of that constituent. For example, a compositional range specifying butene may include a mixture of various isomers of butene. It should be appreciated that the examples supply compositional ranges for various streams, and that the total amount of isomers of a particular chemical composition can constitute a range.

[0079] Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it is noted that the various details described in this disclosure should not be taken to imply that these details relate to elements that are essential components of the various embodiments described in this disclosure, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Rather, the claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described in this disclosure. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.

Claims

CLAIMS1. A method for starting an olefinic material production system, the method comprising: raising the temperature of the combustor of the olefinic material production system from a first temperature that is less than 100 °C to a second temperature range of from 600 °C to 900 °C; circulating a particulate solid between the combustor and a reactor; passing a first stream into the combustor through a gas distributor, wherein the first stream comprises a passivation agent in a first concentration, and wherein the passivation agent comprises one or more of a sulfur-containing compound, a nitrogen-containing compound, a hydroxide moiety-containing compound excluding water, or a phosphorous-containing compound; and following the passing of the first stream into the combustor through the gas distributor, passing a second stream into the combustor through the gas distributor, wherein the second stream present inside the gas distributor and passed into the combustor comprises: the passivation agent in a second concentration, wherein the first concentration is greater than the second concentration; and a supplemental fuel comprising at least 0.01 mol.% of one or more olefins.

2. The method of claim 1, wherein the passivation agent comprises the sulfur-containing compound chosen from hydrogen sulfide, methyl mercaptan, dimethylsulfide (DMS), dimethyl disulfide (DMDS), dipropyldisulphides, dibutyldisulphides, ditertbutyldisulphide (DTBDS), diphenyldisulphide (DPDS), carbon disulphide, benzothiophenes, bibenzyl sulphide, phosphorothioate, methanedithione, methyldisulfanyl, methaylsulfanyl, and dimethyl sulfoxides.

3. The method of any previous claim, wherein the gas distributor comprises stainless steel.

4. The method of any previous claim, wherein the first stream comprises from 15 ppmw to 100 ppmw of the passivation agent, and wherein the second stream comprises from 1 ppmw to 12 ppmw of the passivation agent.

5. The method of any previous claim, wherein the first stream further comprises the supplemental fuel.

6. The method of any previous claim, wherein passing the first stream into the combustor through the gas distributor forms a passivation layer on a surface of the gas distributor that mitigates coking.

7. The method of any previous claim, wherein passing the second stream into the combustor through the gas distributor maintains the passivation layer on the surface of the gas distributor.

8. The method of any previous claim, wherein the supplemental fuel present in the gas distributor and passed into the combustor comprises: at least 90 mol.% of a combination of one or more of hydrogen, methane, ethane, propane, or nitrogen; and from 0.01 mol.% to 2 mol.% of olefins.

9. The method of any previous claim, wherein the supplemental fuel comprises from 5 mol.% to 40 mol.% of methane and from 60 mol.% to 95 mol.% of hydrogen.

10. The method of any previous claim, wherein: the supplemental fuel is an off-gas from a demethanizer from a stream cracking system; the supplemental fuel is natural gas; or the supplemental fuel is from a separate dehydrogenation plant.

11. The method of any previous claim, further comprising, prior to passing the first stream into the combustor through the gas distributor, passing steam into the combustor through the gas distributor.

12. The method of any previous claim, further comprising passing a hydrocarbon feed into the reactor to produce olefinic material.

13. The method of any previous claim, wherein raising the temperature of the combustor from a first temperature range of from 0 °C to 100 °C to a second temperature range of from 600 °C to 900 °C comprises combusting a liquid fuel in the combustor, and wherein the liquid fuel comprises a liquid fuel having an autoignition temperature of less than 400 °C.

14. The method of any previous claim, wherein the olefinic material production system produces propylene by catalytic dehydrogenation.

15. The method of any previous claim, wherein the one or more olefins of the second stream present inside the gas distributor and passed into the combustor are: formed in the gas distributor by dehydrogenation of an alkane; or present in the supplemental fuel when passed into the gas distributor.

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