FIELD

[0001] Systems and methods are provided for integration of fluidized coking with catalytic gasification processes.

BACKGROUND

[0002] Coking is a carbon rejection process that is commonly used for upgrading of heavy oil feeds and/or feeds that are challenging to process, such as feeds with a low ratio of hydrogen to carbon. In addition to producing a variety of liquid products, typical coking processes can also generate a substantial amount coke. Because the coke contains carbon, the coke is potentially a source of additional valuable products in a refinery setting. However, fully realizing this potential remains an ongoing challenge.

[0003] Coking processes in modem refiner}' settings can typically be categorized as delayed coking or fluidized bed coking. Fluidized bed coking is a petroleum refining process in which heavy petroleum feeds, typically the non-distillable residues (resids) from the fractionation of heavy oils are converted to lighter, more useful products by thermal decomposition (coking) at elevated reaction temperatures. Heavy oils which may be processed by the fluid coking process include heavy atmospheric resids, petroleum vacuum distillation bottoms, aromatic extracts, asphalts, and bitumens from tar sands, tar pits and pitch lakes of Canada (Athabasca, Alta.), Trinidad, Southern California (La Brea (Los Angeles), McKittrick (Bakersfield, Calif.), Carpinteria (Santa Barbara County, Calif.), Lake Bermudez (Venezuela) and similar deposits such as those found in Texas, Peru, Iran, Russia and Poland.

[0004] The Flexicoking™ process, developed by Exxon Research and Engineering Company, is a variant of the fluid coking process that is operated in a unit including a reactor and a heater, but also including a gasifier for gasifying the coke product by reaction with an air/steam mixture to form a low heating value fuel gas. A stream of coke passes from the heater to the gasifier where all but a small fraction of the coke is gasified to a low-BTU gas (~120 BTU/standard cubic feet) by the addition of steam and air in a fluidized bed in an oxygen-deficient environment to form fuel gas comprising carbon monoxide and hydrogen. In a conventional Flexicoking™ configuration, the fuel gas product from the gasifier, containing entrained coke particles, is returned to the heater to provide most of the heat required for thermal cracking in the reactor with the balance of the reactor heat requirement supplied by combustion in the heater. A small amount of net coke (about 1 percent of feed) is withdrawn from the heater to purge the system of metals and ash. The liquid yield and properties are comparable to those from fluid coking. The fuel gas product is withdrawn from the heater following separation in internal cyclones which return coke particles through their diplegs.

[0005] The Flexi coking™ process is described in patents of Exxon Research and Engineering Company, including, for example, U.S. Pat. No. 3,661,543 (Saxton), U.S. Pat. No. 3,759,676 (Lahn), U.S. Pat. No. 3,816,084 (Moser), U.S. Pat. No. 3,702,516 (Luckenbach), U.S. Pat. No. 4,269,696 (Metrailer). A variant is described in U.S. Pat. No. 4,213,848 (Saxton) in which the heat requirement of the reactor coking zone is satisfied by introducing a stream of light hydrocarbons from the product fractionator into the reactor instead of the stream of hot coke particles from the heater. Another variant is described in U.S. Pat. No. 5,472,596 (Kerby) using a stream of light paraffins injected into the hot coke return line to generate olefins. U.S. Patent Application Publication 2015/0368572 provides other examples of systems suitable for use with a Flexicoking™ process.

[0006] U.S. Patent 8,1 14,176 describes methods for catalytic steam gasification of petroleum coke to methane. U.S. Patent 6,955,695 describes use of separate gas-fired heaters. U.S. Patent Application Publication 2015/0165380 describes catalytic gasification of petroleum coke using a process that includes impregnation of the coke particles with alkali metal catalyst. U.S. Patent Application Publication No. 2015/0361362 describes a process for catalytic gasification of carbonaceous feedstock.

[0007] One of the difficulties with performing gasification while reducing or minimizing the amount of slag production is that the resulting low-BTU gas is generated at a low pressure. Thus, although the low-BTU gas contains syngas components (Hi and/or CO), finding an improved value use for the low-BTU gas can be difficult due to the combination of low energy value and lo pressure. What is needed are systems and/or methods that can allow for operation of a gasifier under conditions that result in reduced or minimized gasifier slag formation while also providing a syngas-containing product having improved value.

SUMMARY

[0008] In various aspects, a method for performing fluidized coking on a feed is provided. The methods include exposing a feedstock comprising a T10 distillation point of 343°C or more to a fluidized bed comprising solid particles in a reactor under coking conditions to form a coker effluent. The exposing can further include introducing potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof into the fluidized bed comprising solid particles. The potassium carbonate, calcium oxide, and/or calcium salts can be introduced as part of the feedstock or as separate catalyst particles. The thermal cracking conditions can be selected to provide 10 wt% or more conversion of the feedstock relative to 343°C. The method further includes introducing an oxygen-containing stream and steam into a gasifier stage. The method can also include passing at least a portion of the solid particles including deposited coke from the reactor to the gasifier. After passing the solid particles including deposited coke into the gasifier, the solid particles including deposited coke can be exposed to gasification conditions in the presence of potassium carbonate, calcium oxide, or a combination thereof to form partially gasified solid particles and a gas phase product comprising Fh. CO, and CO2. It is noted that any thermally decomposable calcium salts introduced into the fluidized bed can thermally decompose to form calcium oxide under the coking conditions and/or the gasification conditions. The gasification conditions can include a temperature of l200°F to l400°F (~650°C to ~760°C) and a pressure of 20 psig to 600 psig (-140 kPa-g to -4100 kPa-g). After gasification, at least a first portion of the partially gasified solid particles can be removed from the gasifier. At least a second portion of the partially gasified solid particles can be passed from the gasifier to the reactor.

[0009] In some aspects, the solid particles can correspond to coke particles. In such aspects, at least a portion of the potassium carbonate, calcium oxide, or a combination thereof can be deposited on the at least a portion of the solid particles, the first portion of the partially gasified solid particles, and/or the second portion of the partially gasified solid particles.

[0010] In some aspects, at least a portion of the potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof can be entrained in the feedstock. Additionally or alternately, at least a portion of the potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts can be passed into the fluidized bed in a carrier fluid different from the feedstock and/or a carrier fluid included in a second and/or additional portion of the feedstock. Further additionally or alternately, at least a portion of the potassium carbonate, calcium oxide, or combination thereof can correspond to supported potassium catalyst particles, supported calcium catalyst particles, or a combination thereof. The calcium oxide on the supported particles can optionally correspond to calcium oxide formed by thermal decomposition of a thermally decomposable calcium salt. In various aspects, the one or more thermally decomposable calcium salts can correspond to calcium nitrate, calcium carbonate, calcium hydroxide, or a combination thereof. In various aspects, the feedstock can include 0.01 wt% to 0.5 wt% of the potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof.

[0011] In various aspects, a system for performing fluidized coking is also provided. The system includes a fluidized bed coker. The fluidized bed coker includes a reactor, a reactor coker feed inlet, a reactor cold coke outlet, a reactor hot coke inlet, a reactor liquid product outlet, and a fluidized bed of solid particles within the reactor. The fluidized bed of solid particles can include a first portion of solid particles having potassium carbonate, calcium oxide, or a combination thereof supported on the first portion of solid particles. The system can further include a gasifier comprising a gasifier coke inlet in fluid communication with the cold coke outlet, a gasifier coke outlet in fluid communication with the hot coke inlet, at least one gasifier input gas inlet, a fuel gas outlet, and a second portion of solid particles.

[0012] In some aspects, the first portion of solid particles can correspond to coke particles and/or the second portion of solid particles can correspond to partially gasified coke particles. In some aspects, the first portion of solid particles can correspond to potassium carbonate, calcium oxide, or a combination thereof supported on a refractory oxide support.

[0013] In some aspects, the reactor can include a coking zone and a stripping zone. In such aspects, the gasifier coke outlet can be in fluid communication with the coking zone via the hot coke inlet. Additionally or alternately, the gasifier coke outlet can be in fluid communication with the stripping zone via the hot coke inlet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 shows an example of a fluidized bed coking system including a coker, a heater, and a gasifier that is suitable for performing coking and catalytic gasification as described herein.

[0015] FIG. 2 shows another example of a fluidized bed coking system including a coker and a gasifier.

[0016] FIG. 3 shows another example of a fluidized bed coking system including a coker and a gasifier.

DETAILED DESCRIPTION

[0017] All numerical values within the detailed description and the claims herein are modified by“about” or“approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

Overview

[0018] In various aspects, systems and methods are provided for integrating a fluidized coking process with a catalyst-enhanced coke gasification process. The catalyst for the gasification process can correspond to calcium oxide, a thermally decomposable calcium salt, a potassium salt such as potassium carbonate, or a combination thereof. Examples of suitable calcium salts can include, but are not limited to, calcium hydroxide, calcium nitrate, and calcium carbonate. The calcium oxide, potassium salts, and/or thermally decomposable calcium salts can be introduced into the integrated system, for example, as part of the feed into the coker. It has been unexpectedly discovered that using catalytic gasification as part of an integrated fluidized coking and gasification process can result in an overhead gas stream from the gasifier with increased energy content and/or overhead gas pressure. Further additionally or alternately, performing catalytic gasification can increase the relative benefits of integrating fluidized coking with gasification in a two-reactor configuration, as opposed to a traditional three-reactor configuration.

[0019] Introducing a catalyst into the gasification process can allow the gasifier to operate at a temperature of roughly l200°F (~650°C) to l400°F (~760°C). This temperature range is in contrast to the temperature range of ~870°C to ~H00°C that can typically be used for configurations involving a fluidized coker that is thermally integrated with a gasifier.

[0020] One of the difficulties with using petroleum coke, coal, and/or heavy oils as a feed for gasification is that such feeds can potentially contain a relatively high percentage of transition metals, such as iron, nickel, and vanadium. During conventional operation of a gasifier that can individually maintain heat balance (i.e., a gasifier that performs sufficient combustion of carbon with oxygen to at least maintain the gasifier temperature), these transition metals can be converted into a“slag” that tends to be corrosive for the internal structures of the gasifier. As a result, such gasifiers can typically have relatively short operating lengths between shutdown events, such as operating lengths of roughly 3 months to 18 months. For a gasifier that operates in a stand-alone manner, frequent shutdown events may be acceptable. However, for a gasifier that is integrated to provide heat balance to another process, such as a fluidized bed coker, a short cycle length for the gasifier can force a short cycle length for the coker as well.

[0021] It is noted that one option for reducing or minimizing slag formation can be to use gasification conditions that include little or no oxygen. However, gasifiers operated under such conditions typically need to be paired with an additional heat source that can provide heat to the gasifier in order to maintain heat balance during operation. The additional heat source can correspond to a gas-fired heater, a combustor, or another unit that can generate heat for transfer into the gasification environment. Such an additional heat source can be less desirable due to the need for additional refinery footprint and/or the consumption of additional refinery resources.

[0022] In order to overcome the problems related to slag formation, a gasifier that is thermally integrated with a fluidized bed coking process, such as a Flexicoking™ process, can be operated under conditions that reduce, minimize, or eliminate formation of slag while still providing excess heat to the fluidized coking process. This can be achieved, for example, by using a gasification process that includes air as at least a portion of the oxygen source for the gasifier. The additional nitrogen in air can provide a diluent for the gasifier environment that can reduce or minimize slag formation. Instead of forming a slag or other glassy type product containing metals, the metals in the coke can be retained in coke form and purged from the integrated system. This can allow the removal / disposition of the metals to be performed in a secondary device or location. By avoiding formation of the corrosive slag, the cycle length of the integrated coker and gasifier can be substantially improved. Additionally, operating the gasifier in such a manner can avoid the need to include an additional combustor and/or gas-fired heater as a heat source for maintaining heat balance.

[0023] One difficulty with operating an integrated coker and gasifier to avoid slag formation is that the resulting gas phase product generated in the gasifier can have a relatively low BTU value. Because of the substantial amount of nitrogen introduced into the gasifier along with the oxygen, the nitrogen content of the gas phase product generated from a gasifier in an integrated fluidized bed / gasifier system can be up to 55 vol%. This can present a variety of problems when attempting to find a high value use for the carbon in the gas phase product from the gasifier. For example, this gas phase product includes a sufficient amount of diluent (such as nitrogen) that it is not directly suitable as a fuel in various types of burners in a refinery setting. Instead, use of the gas phase product as a fuel may require distribution of the gas phase product across multiple burners, so that the gas phase product can be blended with other fuels having a higher energy density. Another difficulty is that the gas phase product is also a low pressure stream when it emerges from the gasifier. Attempting to compress the gas phase product from the gasifier to match pressures in another processing environment would require compressing the substantial amount of nitrogen in the product, meaning a substantial additional compression cost with little value in return.

[0024] It has been unexpectedly discovered that performing gasification under catalytic gasification conditions can increase the energy content and/or increase the pressure of the gas phase product stream generated by the gasifier. In some aspects, a portion of the benefit of performing catalytic gasification can be an increase in the amount of syngas generated in the gasifier relative to the amount of input steam, nitrogen, and oxygen. Additionally or alternately, the amount of methane generated in the gasifier can be increased. Further additionally or alternately, the resulting pressure of the overhead gas phase product stream generated by the gasifier can be increased. Due in part to the lower gasification temperature that can be used during catalytic gasification, a higher pressure can be used within the gasifier while still reducing or minimizing the amount of slag formation. The higher pressure for the gasification conditions can result in a corresponding higher pressure for the gas phase product (sometimes referred to as“low-BTU” gas) generated by the gasification process.

Catalytic Gasification

[0025] In various aspects, gasification of coke can be performed in the presence of a catalyst that includes potassium, calcium, or a combination thereof. The potassium, calcium, or combination thereof can be in any convenient oxidation state that can result from exposure of the initial potassium-containing and/or calcium-containing compound(s) to the gasification environment. For example, a catalyst including potassium carbonate can remain in a potassium carbonate form within the coker and/or gasifier. Calcium carbonate or calcium hydroxide can tend to decompose under the conditions present in a coker and/or gasifier to form calcium oxide and an additional gas phase product based on the stoichiometry of the initial calcium salt.

[0026] In some aspects, the catalyst including potassium, calcium, or a combination thereof can be introduced into the reaction system as a solid suspended and/or dissolved in the feed to the fluidized coker. In such aspects, the catalyst can be mixed with the feed at any convenient time prior to introducing the feed into the fluidized coking environment. Additionally or alternately, a portion of the catalyst can be introduced into the fluidized coking environment in a hydrocarbon (or hydrocarbon-like) carrier stream that is separate from the feed to the fluidized coker. In such additional or alternate aspects, any convenient carrier can be used that allows the catalyst to be introduced into the fluidized coking environment for eventual deposition on coke particles. After introduction into the fluidized coking environment as part of the feed and/or in a separate carrier stream, the calcium oxide (optionally formed by thermal decomposition) or potassium salt can be deposited on (or otherwise incorporated into) coke particles that are circulated between the coker and the gasifier. The coke particles can thus serve as a“substrate” for support of the calcium oxide or potassium salt.

[0027] In aspects where the coke particles serve as a“substrate” for support of at least a portion of the catalyst, a reduced or minimized amount of catalyst can be used to catalyze the gasification process. In a conventional coke gasification process based on gasification of coke from a delayed coker, the coke particles are typically completely consumed during either gasification or an associated combustion process. By contrast, in a gasification process as described herein, the coke particles are only partially gasified in the gasifier, and then returned to the coker for accumulation of additional coke. A small portion of the coke particles are withdrawn from the reaction system as a purge stream to remove ash, metals, and/or other non-combustible materials that might potentially contribute to formation of slag or other deposits within the gasifier. Because only a small portion of the coke is removed via the purge stream during each cycle through the coker and gasifier, the majority of the catalyst supported on the coke can be retained in the combined fluidized coker and gasifier reaction system. As a result, the amount of catalyst introduced into the gasifier can be unexpectedly lower than the amount of catalyst used in a conventional catalytic gasifier. In various aspects, the amount of catalyst introduced with the feed into the fluidized coker can correspond to from 0.01 wt% to 0.5 wt% of the feed, or 0.01 wt% to 0.3 wt%, or 0.1 wt% to 0.5 wt%, or 0.1 wt% to 0.3 wt%. Optionally, the catalyst removed from the reactor via the purge stream can be recovered by any convenient method, such as for use as recycled catalyst.

[0028] In other aspects, the catalyst including potassium, calcium, or a combination thereof can be introduced into the reactor in the form of a supported catalyst. For example, one or more potassium and/or calcium compounds can be supported on a refractory oxide substrate, such as an alumina substrate. In such aspects, the catalyst particles can be passed between the coker and gasifier along with the coke particles. A portion of the catalyst particles can also be withdrawn as part of the purge stream from the gasifier. Such catalyst particles can be recovered, and optionally recycled for further use.

Example of Configuration for Fluidized Coking with Integrated Gasification

[0029] In this description, the term“Flexicoking” (trademark of ExxonMobil Research and Engineering Company) is used to designate a fluid coking process in which heavy petroleum feeds are subjected to thermal cracking in a fluidized bed of heated solid particles to produce hydrocarbons of lower molecular weight and boiling point along with coke as a by-product which is deposited on the solid particles in the fluidized bed. The resulting coke can then converted to a gas phase product by contact at elevated temperature with steam and an oxygen-containing gas in a gasification reactor (gasifier). This type of configuration can more generally be referred to as an integration of fluidized bed coking with gasification.

[0030] In various aspects, an integrated fluidized bed coker and gasifier, optionally also including a heater, can be used to process a feed by first coking the feed and then gasifying the resulting coke. This can generate a gas phase product, withdrawn from the gasifier or the optional heater, that can then be further processed to increase the concentration of synthesis gas in the product. The product with increased synthesis gas concentration can then be used as an input for production of methanol, optionally after further processing to adjust the Eh to CO ratio in the synthesis gas.

[0031] FIG. 1 shows an example of a Flexicoker unit (i.e., a system including a gasifier that is thermally integrated with a fluidized bed coker) with three reaction vessels: reactor, heater and gasifier. It is noted that there may be some advantages to using catalytic gasification in a reaction system that does not include a separate heater (as further illustrated in FIG. 2), but catalytic gasification can also be compatible for use in a system that includes a heater in a third reaction vessel. In the example shown in FIG. 1, the unit comprises reactor section 10 with the coking zone and its associated stripping and scrubbing sections (not separately indicated), heater section 11 and gasifier section 12. The relationship of the coking zone, scrubbing zone and stripping zone in the reactor section is shown, for example, in U.S. Pat. No. 5,472,596, to which reference is made for a description of the Flexi coking unit and its reactor section. A heavy oil feed is introduced into the unit by line 13 and cracked hydrocarbon product withdrawn through line 14. Fluidizing and stripping steam is supplied by line 15. Cold coke is taken out from the stripping section at the base of reactor 10 by means of line 16 and passed to heater 11. The term“cold” as applied to the temperature of the withdrawn coke is, of course, decidedly relative since it is well above ambient at the operating temperature of the stripping section. Hot coke is circulated from heater 11 to reactor 10 through line 17. Coke from heater 11 is transferred to gasifier 12 through line 21 and hot, partly gasified particles of coke are circulated from the gasifier back to the heater through line 22. The excess coke is withdrawn from the heater 11 by way of line 23. In conventional configurations, gasifier 12 is provided with its supply of steam and air by line 24 and hot gas phase product is taken from the gasifier to the heater though line 25. In some alternative aspects, instead of supplying air via a line 24 to the gasifier 12, a stream of oxygen with 95 vol% purity or more can be provided, such as an oxygen stream from an air separation unit. In such aspects, in addition to supplying a stream of oxygen, a stream of an additional diluent gas can be supplied by line 31. The additional diluent gas can correspond to, for example, CCh separated from the fuel gas generated during the gasification. The gas phase product is taken out from the unit through line 26 on the heater; coke fines are removed from the gas phase product in heater cyclone system 27 comprising serially connected primary and secondary cyclones with diplegs which return the separated fines to the fluid bed in the heater. The gas phase product from line 26 can then undergo further processing. For example, in some aspects, the gas phase product from line 26 can be passed into a separation stage for separation of CCh (and/or H2S). This can result in a stream with an increased concentration of synthesis gas, which can then be passed into a conversion stage for conversion of synthesis gas to methanol.

[0032] It is noted that in some optional aspects, heater cyclone system 27 can be located in a separate vessel (not shown) rather than in heater 11. In such aspects, line 26 can withdraw the gas phase product from the separate vessel, and the line 23 for purging excess coke can correspond to a line transporting coke fines away from the separate vessel. These coke fines and/or other partially gasified coke particles that are vented from the heater (or the gasifier) can have an increased content of metals relative to the feedstock. For example, the weight percentage of metals in the coke particles vented from the system (relative to the weight of the vented particles) can be greater than the weight percent of metals in the feedstock (relative to the weight of the feedstock). In other words, the metals from the feedstock are concentrated in the vented coke particles. Since the gasifier conditions create little or no slag, the vented coke particles correspond to the mechanism for removal of metals from the coker / gasifier environment. In some aspects, the metals can correspond to a combination of nickel, vanadium, and/or iron. Additionally or alternately, the gasifier conditions can cause substantially no deposition of metal oxides on the interior walls of the gasifier, such as deposition (cumulative weight in the form of metal oxides) of less than 0.1 wt% of the metals present (cumulative weight) in the feedstock introduced into the coker / gasifier system, or less than 0.01 wt%.

[0033] In configurations such as FIG. 1, the system elements shown in the figure can be characterized based on fluid communication between the elements. For example, reactor section 10 is in direct fluid communication with heater 11. Reactor section 10 is also in indirect fluid communication with gasifier 12 via heater 11.

[0034] Integration of a fluidized bed coker with a gasifier can also be accomplished without the use of an intermediate heater. In such aspects, the cold coke from the reactor can be transferred directly to the gasifier. This transfer, in almost all cases, will be direct with one end of the tubular transfer line connected to the coke outlet of the reactor and its other end connected to the coke inlet of the gasifier with no intervening reaction vessel, i.e. heater. The presence of devices other than the heater is not however to be excluded, e.g. inlets for lift gas etc. Similarly, while the hot, partly gasified coke particles from the gasifier are returned directly from the gasifier to the reactor this signifies only that there is to be no intervening heater as in the conventional three-vessel Flexicoker™ but that other devices may be present between the gasifier and the reactor, e.g. gas lift inlets and outlets.

[0035] FIG. 2 shows an example of integration of a fluidized bed coker with a gasifier but without a separate heater vessel. In the configuration shown in FIG. 2, the gasifier corresponds to a single gasifier reactor, although the cyclones for separating the gas phase product from catalyst fines are located in a separate vessel. In other aspects, the cyclones can be included in gasifier vessel 41 (i.e., in the single gasifier reactor).

[0036] In the configuration shown in FIG. 2, the configuration includes a reactor 40, a main gasifier vessel 41 and a separator 42. The heavy oil feed is introduced into reactor 40 through line 43 and fluidizing/stripping gas through line 44; cracked hydrocarbon products are taken out through line 45. Cold, stripped coke is routed directly from reactor 40 to gasifier 41 by way of line 46 and hot coke returned to the reactor in line 47. Steam and oxygen are supplied through line 48. The flow of gas containing coke fines is routed to separator vessel 42 through line 49 which is connected to a gas outlet of the main gasifier vessel 41. The fines are separated from the gas flow in cyclone system 50 comprising serially connected primary and secondary cyclones with diplegs which return the separated fines to the separator vessel. The separated fines are then returned to the main gasifier vessel through return line 51 and the gas phase product taken out by way of line 52. Coke is purged from the separator through line 53. The gas phase product from line 52 can then undergo further processing for separation of CC (and/or TkS) and conversion of synthesis gas to methanol.

[0037] FIG. 3 schematically shows some additional details regarding use of catalytic gasification as part of an integrated fluidized coking and gasification reaction system. In FIG. 3, a feed 301 suitable for coking is introduced into fluidized bed coker 312. In the example shown in FIG. 3, prior to the feed 301 entering the coker 312, catalyst 311 for catalytic gasification can be added to feed 301. At startup, a larger amount of catalyst 311 may be added in the feed in order to achieve a desired catalyst concentration within the gasifier. After steady-state operation has been achieved, the catalyst 311 added to feed 301 can correspond to a“make-up” amount of catalyst, as purge stream 362 will typically include a relatively small amount of catalyst relative to the catalyst inventory in the reaction system. The reactor or coking section 317 and stripper section 318 of fluidized bed coker 312 are shown in FIG. 3. The feed 301 can correspond to a heavy oil feed, or any other convenient feed typically used as an input for a coker. In the configuration shown in FIG. 3, the fluidized bed coker 312 is integrated with a catalytic gasifier 316. This combination of elements is similar to the configuration shown in FIG. 2. In other aspects, the fluidized bed coker can be integrated with both a heater and a gasifier.

[0038] In FIG. 3, fluidized bed coker 312 generates a coker effluent 305 that includes fuel boiling range liquids generated during the coking process. Heat for coker 312 can be provided by hot coke recycle line 376 and second hot coke recycle line 386 from gasifier 316. In the configuration shown in FIG. 3, the hot coke recycle line 376 from catalytic gasifier 316 is passed into coking section 317 of coker 312. The second hot coke recycle line 386 from gasifier 316 is passed into stripping section 318 of coker 312. This can provide separate control of the heating in the coking section 317 and stripping section 318 of coker 312. In other aspects, any convenient number and combination of hot coke recycle lines from the gasifier 316 can be used to provide heat to coker 312. For example, in some configurations, only one hot coke recycle line may be present, so that hot coke is returned only to the stripping section 318 or only to the reactor section 316.

[0039] Cold coke from coker 312 is passed into gasifier 316 via line 324. As noted above partly gasified particles of coke are circulated from the gasifier back to the coker 312 through line 376 and/or 386. A gas phase product generated in gasifier 316 can exit as gas phase product stream 321. The gas phase product 321 can include ¾, CO, CO2 (i.e., components of syngas), as well as methane and optionally other light ends. The gas phase product 321 can also include any diluent gases introduced into the reaction system, such as N2 that can be introduced when air is used as the oxygen source for the gasifier. It is noted that gasifier 316 does not generate a slag that is separately removed from the gasifier. Instead, excess coke is withdrawn from the gasifier 316 as a purge stream 362. Optionally, one or more catalyst recovery processes can be performed on purge stream 362 to recover the calcium- or potassium-based catalyst. The nature of the catalyst recovery can be dependent on the type of catalyst used in the catalytic gasifier. Oxygen and steam for the gasifier are introduced, for example, via line 304.

[0040] The coker and gasifier can be operated according to the parameters necessary for the required coking processes. Thus, the heavy oil feed will typically be a heavy (high boiling) reduced petroleum crude; petroleum atmospheric distillation bottoms; petroleum vacuum distillation bottoms, or residuum; pitch; asphalt; bitumen; other heavy hydrocarbon residues; tar sand oil; shale oil; or even a coal slurry or coal liquefaction product such as coal liquefaction bottoms. Such feeds will typically have a Conradson Carbon Residue (ASTM Dl 89-165) of at least 5 wt. %, generally from 5 to 50 wt. %. Preferably, the feed is a petroleum vacuum residuum.

[0041] A typical petroleum chargestock suitable for processing in a fluidized bed coker can have a composition and properties within the ranges set forth below in Table 1.

Table 1: Example of Coker Feedstock

[0042] More generally, the feed to the fluidized bed coker can have a T10 distillation point of 343°C or more, or 37l°C or more.

[0043] The heavy oil feed, pre-heated to a temperature at which it is flowable and pumpable, is introduced into the coking reactor towards the top of the reactor vessel through injection nozzles which are constructed to produce a spray of the feed into the bed of fluidized coke particles in the vessel. Temperatures in the coking zone of the reactor are typically in the range of 450°C to 850°C and pressures are kept at a relatively low level, typically in the range of 120 kPag to 400 kPag (~ 17 psig to 58 psig), and most usually from 200 kPag to 350 kPag (~ 29 psig to 51 psig), in order to facilitate fast drying of the coke particles, preventing the formation of sticky, adherent high molecular weight hydrocarbon deposits on the particles which could lead to reactor fouling. The conditions can be selected so that a desired amount of conversion of the feedstock occurs in the fluidized bed reactor. For example, the conditions can be selected to achieve at least 10 wt% conversion relative to 343°C (or 37l°C), or at least 20 wt% conversion relative 343°C (or 37l°C), or at least 40 wt% conversion relative to 343°C (or 37l°C), such as up to 80 wt% conversion or possibly still higher. The light hydrocarbon products of the coking (thermal cracking) reactions vaporize, mix with the fluidizing steam and pass upwardly through the dense phase of the fluidized bed into a dilute phase zone above the dense fluidized bed of coke particles. This mixture of vaporized hydrocarbon products formed in the coking reactions flows upwardly through the dilute phase with the steam at superficial velocities of roughly 1 to 2 meters per second (~ 3 to 6 feet per second), entraining some fine solid particles of coke which are separated from the cracking vapors in the reactor cyclones as described above. The cracked hydrocarbon vapors pass out of the cyclones into the scrubbing section of the reactor and then to product fractionation and recovery.

[0044] As the cracking process proceeds in the reactor, the coke particles pass downwardly through the coking zone, through the stripping zone, where occluded hydrocarbons are stripped off by the ascending current of fluidizing gas (steam). They then exit the coking reactor and pass to the gasification reactor (gasifier) which contains a fluidized bed of solid particles and which operates at a temperature higher than that of the reactor coking zone. In the gasifier, the coke particles are converted by reaction at the elevated temperature with steam and an oxygen- containing gas into a gas phase product comprising carbon monoxide and hydrogen.

[0045] During catalytic gasification, the gasification zone can be maintained at a temperature ranging from 650°C to 760°C (~ l200°F to ~l400°F) and a pressure ranging from roughly 140 kPa-g to 4100 kPa-g (~20 psig to -600 psig), preferably from roughly 1350 kPa-g to 4100 kPa-g (-200 psig to 600 psig). Steam and an oxygen-containing gas are introduced to provide fluidization and an oxygen source for gasification. In some aspects the oxygen-containing gas can be air. In other aspects, the oxygen-containing gas can have a low nitrogen content, such as oxygen from an air separation unit or another oxygen stream including 95 vol% or more of oxygen, or 98 vol% or more, are passed into the gasifier for reaction with the solid particles comprising coke deposited on them in the coking zone. In aspects where the oxygen-containing gas has a low nitrogen content, a separate diluent stream, such as a recycled CCh or FhS stream derived from the gas phase product produced by the gasifier, can also be passed into the gasifier.

[0046] In the gasification zone the reaction between the coke and the steam and the oxygen- containing gas produces a hydrogen and carbon monoxide-containing gas phase product and a partially gasified residual coke product. Conditions in the gasifier are selected accordingly to generate these products. Steam and oxygen rates (as well as any optional CCh rates) will depend upon the rate at which cold coke enters from the reactor and to a lesser extent upon the composition of the coke which, in turn will vary according to the composition of the heavy oil feed and the severity of the cracking conditions in the reactor with these being selected according to the feed and the range of liquid products which is required. The gas phase product from the gasifier may contain entrained coke solids and these are removed by cyclones or other separation techniques in the gasifier section of the unit; cyclones may be internal cyclones in the main gasifier vessel itself or external in a separate, smaller vessel as described below. The gas phase product is taken out as overhead from the gasifier cyclones. The resulting partly gasified solids are removed from the gasifier and introduced directly into the coking zone of the coking reactor at a level in the dilute phase above the lower dense phase.

[0047] In aspects where a separate heater is present, such as in the example configuration shown in FIG. 1, the pressure of the heater can be similar to the pressure in the gasifier. The temperature in the heater can be similar to the temperature in the gasifier, or the temperature in the heater can be between the temperature of the fluidized coker and the temperature of the gasifier. Example: Gas Phase Product Generated During Catalytic Gasification

[0048] Non-catalytic and catalytic gasification were performed in a gasification stage using coke generated in a fluidized coker. The gasification stage included separate reactors for steam gasification and air gasification. The rate of introduction of coke into the gasification stage was selected to be representative of the flow rate during an integrated fluidized coking and gasification process (such as a with a gasifier corresponding to a single gasifier reactor). Air was used as the oxygen source for the gasifier. For the conventional (non-catalytic) gasification, the temperature of the steam in the steam gasifier was l600°F (~870°C) while the temperature of the steam for the catalytic gasification was l300°F (~705°C). The pressure was between 1350 kPa-g and 4100 kPa- g. The temperature of the oxygen-containing stream (air) introduced into both air gasification reactors was constant at roughly l700°F (~925°C). For the catalytic gasification, the coke feed to the gasifier included 1 wt% of calcium oxide. This is believed to be representative of the amount of calcium oxide that would be present at steady-state during operation of an integrated fluidized coker and catalytic gasifier as described herein, with a catalyst addition rate of 0.01 - 0.5 wt% of feed.

[0049] Table 2 shows additional details regarding the operating conditions for the gasifiers and the resulting gas phase products generated by the gasifiers. In Table 2, the amounts of product gases are reported based on the heating value (in BTUs) of the gases. In Table 2, syngas was defined as having a ratio 0GH2 to CO of 2.1. Any excess H2 or CO different from this defined ratio was accounted for as part of the Low BTU gas. For the relative syngas amounts in the final two lines of Table 2, the amount of syngas generated by the traditional gasification process was used as a baseline, and thus has a relative value of 1.

Table 2: Traditional and Catalytic Gasification of Coke

[0050] In Table 2, the total heating value of gases is increased when using catalytic gasification. This includes an increase in the amounts of syngas (at a Hr : CO ratio of 2.1) and methane. The heating value of the remaining low BTU gas (LBG) includes any Th and CO not accounted for as syngas, as well as the methane noted in Table 1. As shown in Table 1, the heating value of syngas generated during catalytic gasification is increased by roughly 10% relative to the corresponding heating value of syngas generated by conventional gasification. Similarly, the heating value of the total product from catalytic gasification was increased by roughly 5% relative to the traditional gasification process. Additionally, the syngas includes an increased amount of methane. The amount of coke gasified under the steam gasification conditions is also increased, due in part to the increased pressure that can be used in the gasifier under catalytic gasification conditions.

[0051] It is noted that the catalytic gasification process described in this example can also be performed using a gasifier corresponding to a single gasifier reactor. In such an aspect, both steam and air are can be introduced into the gasifier. This results in production of a gas phase product that includes synthesis gas, but that also includes at least a portion of the N ₂ introduced into the gasifier as part of the air.

Additional Embodiments

[0052] Embodiment 1. A method for performing fluidized coking on a feed, comprising: exposing a feedstock comprising a T10 distillation point of 343°C or more to a fluidized bed comprising solid particles in a reactor under coking conditions to form a coker effluent, the thermal cracking conditions comprising 10 wt% or more conversion of the feedstock relative to 343°C, the thermal cracking conditions being effective for depositing coke on the solid particles, wherein the exposing further comprises introducing potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof into the fluidized bed comprising solid particles; introducing an oxygen-containing stream and steam into a gasifier stage, the oxygen- containing stream optionally comprising air; passing at least a portion of the solid particles comprising deposited coke from the reactor to the gasifier; exposing the at least a portion of the solid particles comprising deposited coke to gasification conditions in the presence of at least a portion of the steam, oxygen from the oxygen-containing stream, and potassium carbonate, calcium oxide, or a combination thereof to form partially gasified solid particles and a gas phase product comprising EE, CO, and CO2, the gasification conditions comprising a temperature of l200°F to l400°F (~650°C to ~760°C) and a pressure of 20 psig to 600 psig (-140 kPa-g to -4100 kPa-g); removing at least a first portion of the partially gasified solid particles from the gasifier; and passing at least a second portion of the partially gasified solid particles from the gasifier to the reactor, the gasifier optionally comprising a single gasifier reactor, the oxygen-containing stream optionally comprising air.

[0053] Embodiment 2. The method of Embodiment 1 , wherein the solid particles comprise coke particles, and optionally wherein at least a portion of the potassium carbonate, calcium oxide, or combination thereof comprises potassium carbonate, calcium oxide, or a combination thereof deposited on i) the at least a portion of the solid particles, ii) the first portion of the partially gasified solid particles, iii) the second portion of the partially gasified solid particles, or iv) a combination thereof.

[0054] Embodiment 3. The method of any of the above embodiments, wherein the potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof is entrained in the feedstock.

[0055] Embodiment 4. The method of any of the above embodiments, wherein introducing potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof into the fluidized bed of solid particles comprises: introducing the potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof into the fluidized bed of solid particles in a carrier fluid different from the feedstock.

[0056] Embodiment 5. The method of any of Embodiments 1 - 3, wherein a second portion of the feedstock comprises the potassium carbonate, calcium oxide, thermally decomposable calcium salt, or a combination thereof, the second portion of the feedstock further comprising a carrier fluid.

[0057] Embodiment 6. The method of any of the above embodiments, wherein the one or more thermally decomposable calcium salts comprise calcium nitrate, calcium carbonate, calcium hydroxide, or a combination thereof.

[0058] Embodiment 7. The method of any of the above embodiments, wherein the feedstock comprises 0.01 wt% to 0.5 wt% of the potassium carbonate, calcium oxide, one or more thermally decomposable calcium salts, or a combination thereof (or 0.01 wt% to 0.3 wt%, or 0.1 wt% to 0.5 wt%, or 0.1 wt% to 0.3 wt%).

[0059] Embodiment 8. The method of any of the above embodiments, wherein the potassium carbonate, calcium oxide, or combination thereof comprises supported potassium catalyst particles, supported calcium catalyst particles, or a combination thereof, the method optionally further comprising recovering the supported potassium catalyst particles, the supported calcium catalyst particles, or a combination thereof and recycling the supported potassium catalyst particles, the supported calcium particles, or a combination thereof to at least one of the reactor and the gasifier stage.

[0060] Embodiment 9. The method of any of the above embodiments, wherein the coking conditions comprise a temperature of 950°F to H00°F (~5l0°C to ~595°C) and a pressure of 20 psig to 600 psig (-140 kPa-g to -4100 kPa-g); or wherein the gasification conditions comprise a pressure of 200 psig to 600 psig (-1400 kPa-g to -4100 kPa-g); or a combination thereof.

[0061] Embodiment 10. The method of any of the above embodiments, wherein the first portion of partially gasified solid particles comprises a first weight percentage of metals (optionally a first combined weight percentage of Ni, V, Fe), relative to a weight of the first portion of partially gasified coke particles, that is greater than a weight percentage of metals (optionally a combined weight percentage of Ni, V, Fe) in the feedstock, relative to a weight of the feedstock.

[0062] Embodiment 11. The method of any of the above embodiments, wherein the exposing the at least a portion of the solid particles comprising deposited coke to gasification conditions results in cumulative deposition of less than 0.1 wt% of metals on the gasifier wall, relative to the feedstock’s cumulative metals content.

[0063] Embodiment 12. The method of any of the above embodiments, wherein passing at least a second portion of the partially gasified solid particles from the gasifier to the reactor comprises a) passing at least a second portion of the partially gasified solid particles from the gasifier to a coking section of the reactor; b) passing at least a second portion of the partially gasified solid particles from the gasifier to a stripping section of the reactor; or c) a combination of a) and b).

[0064] Embodiment 13. A system for performing fluidized coking, comprising: a fluidized bed coker comprising a reactor, a reactor coker feed inlet, a reactor cold coke outlet, a reactor hot coke inlet, a reactor liquid product outlet, and a fluidized bed of solid particles within the reactor, the fluidized bed of solid particles comprising a first portion of solid particles having potassium carbonate, calcium oxide, or a combination thereof supported on the first portion of solid particles; and a gasifier comprising a gasifier coke inlet in fluid communication with the cold coke outlet, a gasifier coke outlet in fluid communication with the hot coke inlet, at least one gasifier input gas inlet, a fuel gas outlet, and a second portion of solid particles, the gasifier optionally comprising a single gasifier reactor.

[0065] Embodiment 14. The system of Embodiment 13, wherein the first portion of solid particles comprises coke particles and/or the second portion of solid particles comprises partially gasified coke particles; or wherein the first portion of solid particles comprise potassium carbonate, calcium oxide, or a combination thereof supported on a refractory oxide support; or a combination thereof.

[0066] Embodiment 15. The system of Embodiment 13 or 14, wherein the reactor comprises a coking zone and a stripping zone, wherein a) the gasifier coke outlet is in fluid communication with the coking zone via the hot coke inlet, b) the gasifier coke outlet is in fluid communication with the stripping zone via the hot coke inlet, or c) a combination of a) and b).

[0067] When numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated. While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains.

[0068] The present invention has been described above with reference to numerous embodiments and specific examples. Many variations will suggest themselves to those skilled in this art in light of the above detailed description. All such obvious variations are within the full intended scope of the appended claims.