Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
  • C10G11/14—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts
  • C10G11/18—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts according to the "fluidised-bed" technique
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/80—Mixtures of different zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1836—Heating and cooling the reactor
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G32/00—Refining of hydrocarbon oils by electric or magnetic means, by irradiation, or by using microorganisms
  • C10G32/02—Refining of hydrocarbon oils by electric or magnetic means, by irradiation, or by using microorganisms by electric or magnetic means
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G51/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more cracking processes only
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/00106—Controlling the temperature by indirect heat exchange
  • B01J2208/00265—Part of all of the reactants being heated or cooled outside the reactor while recycling
  • B01J2208/00283—Part of all of the reactants being heated or cooled outside the reactor while recycling involving reactant liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/00433—Controlling the temperature using electromagnetic heating
  • B01J2208/00442—Microwaves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/0053—Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
  • B01J29/084—Y-type faujasite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively

Definitions

• Refiners have tried to minimize the amount of residual fuel oil produced from a given volume of crude by both catalytic and thermal approaches.
• Visbreaking is a relatively mild thermal cracking process primarily used to reduce the viscosity and pour point of vacuum tower bottoms enough to meet the specifications of No. 6 fuel oil, or at least to reduce the amount of refinery cutting stock required to dilute the resid to meet the specifications.
• Coking is a popular way of recovering lighter, more valuable products from resids.
• delayed coking the residual feed is heated in a furnace and then charged to one or more coke drums where coke (which is believed to be a polymer) forms.
• coke which is believed to be a polymer
• the net effect of coking is to convert a hydrogen deficient heavy fuel (resid) into two fractions, a very hydrogen deficient material (coke) and a relatively hydrogen enriched materials (coke or gas oil).
• Coking produces valuable liquid products, but converts a good portion of the feed to low value coke, frequently 20 to 30 wt _ coke is produced.
• Catalytic routes to upgrading of heavy oil generally involve hydrotreating, hydrocracking, or catalytic cracking. In general these processes have not been too successful because the residual feeds contain a lot of sulfur and nitrogen, and high levels of.metals which poison catalyst. In addition, the large amount of asphaltenes present in the feed tend to rapidly poison the catalyst.
• FCC fluidized catalytic cracking
• a naphtha feed and a gas oil feed are converted in the presence of amorphous or zeolite cracking catalyst in a riser reactor to high octane gasoline.
• U.S. 4,336,160 reduces hydrothermal degradation of conventional FCC catalyst by staged regeneration. However, all the catalyst from the reactor still is regenerated, thus providing opportunity for hydrothermal degradation.
• a low molecular weight carbon-hydrogen contributing material and a high molecular weight feedstock e.g., a gas oil
• zeolite catalysts e.g., zeolite Y with ZSM-5.
• the resulting cracking and carbon-hydrogen additive products are superior to those formed in the absence of the low molecular weight carbon-hydrogen contributing material.
• Advantages of the process include Improved crackability of heavy feedstocks, increased gasoline yield and quality, and better fuel oil with less sulfur and nitrogen. The need for high pressure hydrotreaters and hydrocrackers is reduced or eliminated.
• an elutriable catalyst e.g., a mixture of low coke-forming, long lasting additive catalyst such as ZSM-5 with conventional FCC catalyst allows refiners to break the chains that heretofore made regeneration of additive catalysts proceed in lockstep with the conventional catalyst regeneration. Catalyst elutriation allows more efficient fragment generation, and more efficient cracking of the heavy feed.
• the present invention provides a feed activation catalytic process for upgrading a heavy, hydrogen deficient feed comprising" subjecting the heavy, hydrogen deficient to treatment prior to catalytic cracking, which increases the activity of the feed for subsequent catalytic upgrading by adding energy to the feed prior to catalytic treatment; and, passing the activated feed, without intermediate storage thereof, into a catalytic processing zone to produce a catalytically upgraded product.
• Additive FCC catalysts e.g., ZSM-5 in a matrix
• E- deficient feeds e.g., Resids
• EL rich feeds e.g., propane
• FCC cracking conditions e.g., single or dual riser
• FCC fragment generation e.g., cracking propane
• FCC catalyst regeneration e.g., w/air
• FCC catalyst reactivation e.g., w/olefins
• Figure 1 is a schematic diagram of a dual riser FCC system of a first embodiment of the Invention
• Figure 2 is a schematic diagram of a single riser FCC system of a second embodiment of the invention.
• Figure 3 is a schematic diagram of a dual riser FCC system of a third embodiment of the invention.
• Figure 4 is another embodiment of the invention, using an elutriable catalyst mixture, an elutriating riser reactor, and elutriating stripper, and a visbroken resid feed.
• the activation pretreatment can be any treatment which imparts enough energy into the heavy feeds to make them more susceptible to upgrading in downstream conventional catalytic processes.
• Activation energy can be added to the feed via radiation, e.g., microwave radiation, laser radiation, or ultrasound, or by severe thermal pretreatment, e.g., heating.
• radiation e.g., microwave radiation, laser radiation, or ultrasound
• severe thermal pretreatment e.g., heating.
• heating the feed is preferred, because it is easy to heat a refinery stream in a fired heater, heat exchanger, or the like.
• the more exotic energy sources such as lasers and microwaves may also be used, preferably in conjunction with heating. Although these exotic sources are far more costly than simple high temperature, the exotic sources can be fine tuned to activate selected portions of the charge stock, whereas much less selective activation is possible with a thermal pretreatment.
• Visbreaking or viscosity breaking, is a well known petroleum refining process in which reduced crudes are pyrolyzed, or cracked, under comparatively mild conditions to provide products having lower viscosities and pour points, thus reducing the amounts of less viscous and more valuable blending oils required to make the residual stocks useful as fuel oils.
• the visbreaker feedstock usually consists of a mixture of two or more refinery streams derived from sources such as atmospheric residuum, vacuum residuum, furfural-extract, propane-deasphalted tar and catalytic cracker bottoms. Most of these feedstock components, except the heavy aromatic oils, behave relatively independently in the visbreaking operation.
• the severity of the operation for a mixed feed is limited greatly by the least desirable (highest coke-forming) components.
• the crude or resid feed is passed through a heater and heated to about 425 to about 525°C at about 450 to about 7000 kPa.
• Light gas-oil may be recycled to lower the temperature of the effluent to about 260 to about 370°F.
• Cracked products from the reaction are flash distilled with the vapor overhead being fractionated into a light distillate overhead product, for example gasoline and light gas-oil bottoms, and the liquid bottoms are vacuum fractionated into heavy gas-oil distillate and residual tar.
• ERT reaction time at 800°F
• visbreakers operate at reaction severities of 250 to 1500 ERT seconds.
• Cokers operate typically at 2000 to 5000 ERT.
• severities similar to those used in classical visbreaking operations be used, e.g., 500 to 1500 ERT seconds. _,
• Some of the reactive heavy intermediates formed by the pretreatment process of the present invention may react with other reactive heavy intermediate species, or with some other part of the heavy feed to form solids.
• Thermal pretreatment should not be so severe as to generate any significant amount of coke or solids.
• the upper limits on solids generation is 1-2 wt. %, though operation with generation of less than 0.5 wt. . solids, and more preferably less than 0.1 wt % solids is preferred.
• Temperatures which may be used In thermal processing preferably range from 800 to 1500°F, more preferably from 900 to 1200°F, measured at the outlet of the thermal process.
• the upper limit on severity is about 200 to 5000. This material would readily form coke if sent to a coking drum, but will be exceedingly reactive if promptly fed to an FCC or other catalytic unit.
• Generation of solids refers to solids generation between activation and downstream catalytic process. Severe thermal pretreat ent, as used herein, could result in formation of solids after several days or weeks of standing. This is not too severe, because preferably only a few minutes, elapse between pretreatment and catalytic treatment.
• the optimum thermal pretreatment severity is believed to corresponding to a visbreaking pretreatment which is severe enough to caus instability problems in the visbroken fuel in storage.
• This severely visbroken charge stock does not immediately form sediment, the sediment forms gradually in a storage tank.
• This severely treated material, which contains many reactive fragments, is an ideal feedstock for downstream catalytic processing units, but is unsuitable for storage as fuel, because it will develop sediment after standing for one or two weeks in a storage tank.
• the severe thermal treatment is conducted at sufficient pressure to maintain at least 50 wt . of the heavy feed in liquid phase.
• a hydroaromatic solvent such as is disclosed in US 4,615,791, to Choi, et al, incorporated herein by reference, is helpful.
• soaking factor the term “ERT” or “Equivalent Reaction Time” in seconds as measured at 427°C is used herei to express visbreaking severity; numerically, soaking factor is the same a ERT.
• ERT refers to the severity of the operation, expressed as seconds of residence time in a reactor operating at 427°C.
• the reaction rate doubles for every 12 to 13°C increase in temperature.
• 60 seconds of residence time at 427°C is equivalent to 60 ERT, and increasing the temperature to 456°C would make the operation five times as severe, i.e. 300 ERT.
• 300 seconds at 427°C is equivalent to 60 seconds at 456°C, and the same product mix and distributio should be obtained under either set of conditions.
• Some visbreaker units operate with 20-40% vaporization at the visbreaker coil outlet. Light solvents will vaporize more and the vapor will not do much good towards improving the cracking of the liquid phase material. Accordingly, liquid phase operation is preferred, but significan amounts of vaporization can be tolerated.
• visbreaker units are built with a coil, and when an expansion of the unit's capacity is desired it is cheaper to add a soaking drum (and increase the oil's residence time) than to build and operate a bigger furnace and achieve a higher reactor temperature.
• Typical of the coil/soaking drum combinations is the process described in U.S. Patent 4,247,387.
• the preferred hydro-aromatic solvents which may be used in the visbreaking process are thermally stable, polycyclic, aromatic/hydroaromatic distillate hydrogen donor.materials, preferably resulting from one or more petroleum refining operations.
• the hydrogen-donor solvent nominally has an average boiling point of 200 to 500°C, and a density of 0.85 to 1.1 g/cc.
• suitable hydrogen-donors are highly aromatic petroleum refinery streams, such as fluidized catalytic cracker (FCC) "main column” bottoms, FCC “light cycle oil,” and thermofor catalytic cracker (TCC) "syntower” bottoms, all of which contain a substantial proportion of polycyclic aromatic hydrocarbon constituents such as naphthalene, dimethylnaphthalene, anthracene, phenanthrene, fluorene, chrysene, pyrene, perylene, diphenyl, benzothiophene, tetralin and dihydronaphthalene, for example.
• FCC fluidized catalytic cracker
• TCC thermofor catalytic cracker
• FCC main column bottoms refinery fraction is a highly preferred hydrogen donor solvent.
• a typical FCC main column bottoms (or FCC clarified slurry oil (CSO)) contains a mixture of constituents as represented in the following mass spectrometric analysis:
• Aromatics
• thermofor catalytic cracking is roughly analogous to FCC; both processes operate without addition of hydrogen, both operate at relatively low pressure, and both require frequent regeneration of catalyst.
• the products of thermofor catalytic cracking will have hydrogen contents and distribution very similar to those obtained as a result of FCC. Accordingly, light cycle oils obtained as product streams from a TCC process, or main column bottoms streams obtained as a result of a TCC process, are also suitable for use as hydroaromatic solvents.
• the lubricating oil may be either a paraffin based oil or a naphthenic based oil.
• the lubricating oil is first subjected to aromatics extraction, so that the extract will have more ideal properties.
• the aromatic extract from a lube oil plant is highly aromatic and not a good hydrogen-donor; however, it may be hydrogenated to produce a hydrogen-donor diluent with the right hydrogen content and distribution.
• Diluents or solvents with the right hydrogen content and distribution are produced also by the catalytic dewaxing of lubricating oil stocks and the catalytic dewaxing of fuels.
• Another suitable hydrogen donor solvent source is the highly aromatic tars produced in olefin crackers.
• the hydrogen-donor solvent is its particular proportions of aromatic, naphthenic and paraffinic moieties and the type and quantity of hydrogen associated therewith.
• a high content of aromatic and naphthenic structures together with a high content of alpha hydrogen provides a superior hydrogen-donor material.
• the solvents preferred are hydro-aromatic solvents.
• the hydrogen transfer ability of a donor material can be expressed in terms of specific types of hydrogen content as determined by proton nuclear magnetic resonance spectral analysis. Nuclear magnetic resonance characterization of heavy hydrocarbon oils is well developed. The spectra are divided into four bands according to the following frequencies in Hertz (Hz) and chemical shift (ppm): alpha beta gamma H Ar
• H. protons are attached directly to aromatic rings and are a measure of aro aticity of a material.
• protons are attached to non-aromatic carbon atoms themselves attached directly to an aromatic ring structure, for example alkyl groups and naphthenic ring structures.
• H, t protons are attached to carbon atoms which are in a second position away from an aromatic ring °
• Hgam __m a protons are attached to carbon atoms which are in a third position or more away from an aromatic ring structure. This can be illustrated by the following:
• alpha hydrogens are not donatable, for example the alpha hydrogen in toluene.
• H , , protons are important because of their strong solvency power.
• a high content of H al ⁇ . protons is particularly significant because H , , protons are labile and are potential hydrogen-donors.
• the hydrogen-donor materials if used should have an H ⁇ r proton content is at least 20 percent, preferably from 20 to 50 percent, and an H al p ha P roton content is at least 20 percent, preferably from 20 to 50 percent.
• the alpha-hydrogen content should be at least 1.9 weight % (20% of total hydrogen content).
• the balance of the hydrogen is non- alpha-hydrogen.
• Hydrogen-donors possessing the desired hydrogen content distribution may frequently be obtained as a bottoms fraction from the catalytic cracking or hydrocracking of gas oil stocks in the moving bed or fluidized bed reactor processes.
• a high severity cracking process results in a petroleum residuum solvent having an increased content of H. and H a ⁇ Dna protons and a decreased content of the less desirable non- alpha-hydrogen.
• TCC Thermofor Catalytic Cracking
• SRC Oil Solvent Refines Coal Recycle Oil
• the upper limit on thermal treatments is coking.
• the thermal treatment should not be severe enough to result in significant coke generation upstream of, or in, the catalytic cracking unit. Close coupling of a delayed coking furnace with an FCC unit may permit very severe thermal pretreatment of the feed without significant coke generation, as long as the material coming out of the coking furnace is charged directly to the FCC unit, before it has a time to form coke.
• the present invention does not involve recovery of byproduct streams from thermal processing and charge of these streams to the catalytic cracking unit. Operation of a conventional delayed coker to form coke and lighter materials, such as coke or gas oil, with passage of coke or gas oil to an FCC unit is not part of the present invention.
• thermal treatment generates short lived reactive species, perhaps free radicals, which are very amenable to catalytic cracking, but which disappear within a few minutes.
• no more than 10 minutes should elapse between thermal treatment and catalytic treatment, and most preferably no more than one minute separates the two processes.
• the thermal treatment process used preferably is a liquid phase process, such as visbreaking, which does not result in formation of any substantial amount of coke or solid material. It is believed that the reactive species formed in thermal treatment are the coke precursors which form coke in, e.g., a delayed coking drum. Allowing the reactive species to react with one another and form coke defeats the whole point of thermal processing. Thus operation of a fluid coker upstream of an FCC unit would not achieve any benefit because although reactive species would undoubtedly form, they would react with themselves to form coke rather than remain reactive for better upgrading in the FCC reactor. . ⁇ g _
• H 2 deficient feed e.g., residuum
• microwave treatment exposure to microwave energy in the range
• the microwave energy heats a preheated resid to 600°-1100°F (316° - 593°C) in, at most, 5 minutes.
• the microwave energy heats the resid to 820° - 1100°F (438° -
• the microwave energy heats the resid to 900° - 1100°F (482° -
• enough microwave energy is added to heat the feed at least 25°F (14°C), more preferably by over 50°F (28°C), and most preferably by over 100°F (56°C).
• Any conventional hydrotreating process can be used. Such processes typically operate with relatively high hydrogen partial pressures, on the order of 100-1000 psig (790 to 7,000 kPa), and preferably at 150-450 psig (1100 to 3200 kPa).
• hydrotreating catalyst comprise a catalyst support, usually a high surface area material such as alumina, containing one or more hydrogenation/dehydrogenation components. Any hydrotreating catalyst now known or hereafter developed can be used.
• the thermally activated heavy feeds are much easier to hydrotreat than feeds which have not been preactivated.
• the activated heavy feed may be charged to any conventional hydrocracking unit.
• Such units usually operate at relatively high hydrogen partial pressures and elevated temperatures.
• Auitable catalysts and operating conditions are disclosed in U.S. Patent 4,435,275 and in European Patent 0098040, both of which are incorporated by reference.
• the hydrocracking catalyst can be all amorphous, but preferably contains some zeolite, such as zeolite-Y, along with a hydrogenation/dehydrogenation component. Any hydrocracking catalyst now known or hereafter developed can be used.
• the catalysts whether hydrotreating or hydrocracking, have a relatively large percent of their pore volume in relatively large pores.
• FCC catalysts are either amorphous or zeolitic.
• Most FCC's use zeolitic catalyst, typically a large pore zeolite, in a matrix which may or may not possess catalytic activity.
• Most zeolites typically used have crystallographic pore dimensions of 7.0 angstroms and above for their major pore opening.
• Zeolites usually used in cracking catalysts are zeolite X (U.S. 2,882-, ⁇ 244) and zeolite Y (U.S. 3,130,007). Silicon-substituted zeolites, described in U.S. 4,503,023 can also be used.
• amorphous and/or large pore crystalline cracking catalysts can be used as the conventional catalyst.
• Preferred conventional catalysts are the natural zeolites ordenite and faujasite and the synthetic zeolites X and Y with particular preference given zeolites Y, REY, USY and RE-USY.
• the present invention permits use of an optional additive catalyst, with different properties than the conventional catalyst, when catalytic cracking of activated resid is practiced.
• Preferred additives comprise the shape selective medium pore zeolites exemplified by ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-48 and similar materials.
• ZSM-5 is described in U.S. 3,702,886, U.S. Reissue 29,948 and in U.S. 4,061,724 (describing a high silica ZSM-5 as "silicalite").
• ZSM-23 is described in U.S. 4,076,842.
• ZSM-35 is described in U.S. 4,016,245.
• ZSM-48 is described in U.S. 4,375,573.
• ZSM-5 is particularly preferred.
• the additive zeolites can be modified in activity by dilution with a matrix component of significant or little catalytic activity.
• the matrix may act as a coke sink.
• Catalytically active, inorganic oxide matrix material is preferred because of its porosity, attrition resistance and stability under the cracking reaction conditions encountered particularly in a fluid catalyst cracking operation.
• the additive catalyst may contain up to 50 wt % crystalline material and preferably from 0.5 to 25 wt % in a matrix.
• the matrix may include, or may be, a raw or natural clay, a calcined clay, or a clay which has been chemically treated with an acid or an alkali medium or both.
• Zeolites in which some other framework element which is present in partial or total substitution of aluminum can be advantageous.
• such catalysts may convert more feed to aromatics with higher octanes.
• Elements which can be substituted for part or all of the framework aluminum are boron, gallium, zirconium, titanium and other metals.
• Specific examples of such catalysts include ZSM-5 or zeolite beta containing boron, gallium, zirconium and/or titanium.
• these and other catalytically active elements can also be deposited upon the zeolite by any suitable procedure, e.g., impregnation.
• the zeolite can contain a hydrogen-activating function, e.g., a metal such as platinum, nickel, iron, cobalt, chromium, thorium (or other metal capable of catalyzing the Fischer-Tropsch or water-gas shift reactions) or rhenium, tungsten, molybdenum (or other metal capable of catalyzing olefin disproportionation).
• a metal such as platinum, nickel, iron, cobalt, chromium, thorium (or other metal capable of catalyzing the Fischer-Tropsch or water-gas shift reactions) or rhenium, tungsten, molybdenum (or other metal capable of catalyzing olefin disproportionation).
• Other additives can also be present, e.g., So ⁇ or N0 ⁇ removal additives, metals removing additives and the like.
• Suitable hydrogen-rich hydrocarbon feeds are those containing 12 to 25 wt % hydrogen, e.g., CH., CJ ⁇ g, C-rHg, light virgin naphtha, and similar materials. Any or all of the C, to C ⁇ hydrocarbons recovered from the process can be used as S-- rich feed to the lower region of the riser where these and other hydrogen-rich hydrocarbon materials undergo thermal cracking due to the hot, freshly regenerated cracking catalyst and/or shape selective catalytic cracking and other reactions due to the additive, e.g., the medium pore zeolite catalyst.
• the H 2 ⁇ rich feed when cracked in the base of the riser generates gasiform material contributing mobile hydrogen species and/or carbon-hydrogen fragments.
• the resid has a relatively short residence time in the riser.
• the activated resid quickly cracks when it contacts catalyst, and thus has little time for coking.
• the resid residence time in the riser is less than 1 second, and most preferably between 0.5 and 1 second, to provide sufficient time for cracking while minimizing coking.
• the light, H 2 -rich feed may be converted into light reactive fragments thermally, catalytically, or both.
• Contact of H 2 -rich feed with hot, regenerated conventional FCC catalyst will both thermally and catalytically crack the feed into reactive fragments.
• the concept of generating light fragments is different from the concept of generating heavy, reactive intermediate species by resid feed pretreatment.
• Temperatures can range from 593 to 816°C (1100 to 1500°F) and preferably 677 to 732°C (1250 to 1350°F).
• the catalyst to feed ratio can be 50:1 to 200:1 and preferably is 100:1 to 150:1.
• the catalyst contact time can be 10 to 50 seconds and preferably is 15 to 35 seconds. Light olefin production is maximized by less severe operation.
• Suitable charge stocks for activation comprise the heavy hydrocarbons generally and, in particular, conventional heavy petroleum fractions, e.g., gas oils, thermal oils, residual oils, cycle stocks, whole crudes, tar sand oils, shale oils, synthetic fuels, heavy hydrocarbon fractions derived from the destructive hydrogenation of coal, tar, pitches, asphalts, hydrotreated feedstocks derived from any of the foregoing, and the like.
• conventional heavy petroleum fractions e.g., gas oils, thermal oils, residual oils, cycle stocks, whole crudes, tar sand oils, shale oils, synthetic fuels, heavy hydrocarbon fractions derived from the destructive hydrogenation of coal, tar, pitches, asphalts, hydrotreated feedstocks derived from any of the foregoing, and the like.
• any heavy conventional feedstock, and preferably a hydrogen-deficient feedstock can be used in the process of this invention.
• a riser elutriation zone When an elutriatable catalyst is used in a downstream FCC process it is preferred to have a riser elutriation zone. This can be a zone at either the bottom or top of the riser of increased cross-sectional area. The increased cross-sectional area results in lower superficial vapor velocity in the riser, which allows the catalyst (preferably the additive) with the highest settling velocity to remain longer in the riser.
• the feed rate, riser cross-sectional area, and additive catalyst properties should be selected so that the additive catalyst settling rate approaches the superficial vapor velocity expected in the riser.
• riser expansion to handle increased molar volumes in the riser reactor would not change superficial vapor velocity and would not produce significant elutriation. Conversely, a constant diameter riser would provide elutriation at the base of the riser.
• a elutriatable catalyst mixture When a elutriatable catalyst mixture is used, it is preferred to operate with a catalyst stripper which separates more from less elutriatable catalyst.
• Separation in the stripper can be achieved by particle size difference alone, i.e., a sieve action.
• a stripper is used which separates conventional catalyst from additive catalyst by exploiting differences in settling velocity.
• Stripper elutriation separates additive catalyst from conventional catalyst upstream of the catalyst regenerator. If elutriation occurred in the catalyst regenerator, then the additive catalyst (which may not need re eneration and may be damaged by regeneration) is unnecessarily subjected to regeneration. Thus stripper elutriation significantly reduces additive catalyst residence time in the FCC regenerator.
• Regenerator elutriation would minimize damage to additive catalyst and may be a beneficial way of quickly removing from the regenerator small amounts of additive which will spill over into the regenerator.
• the additive catalyst being a denser catalyst which settles rapidly, minimize loss of additive catalyst with catalyst fines. If elutriating cyclones were used to separate a light, readily elutriable additive from reactor effluent prior to discharge from the reaction vessel, then there would be a significant increase in loss of additive catalyst with fines. There would also be a significant dilution effect caused by accumulation of conventional catalyst fines with more elutriatable additives. Finally use of a light additive would reduce the residence time of the additive in the FCC riser reactor, because it would tend to be blown out of the reactor faster than the conventional catalyst.
• Stripping efficiency can be improved by adding one or more light olefins to a stripping zone.
• the light olefins form higher molecular weight products (which are valuable) and heat (which aids stripping).
• olefins should be added to heat the catalyst at least 28°C (50°F) and preferably at least 56°C (100°F) or more.
• FCC CONVENTIONAL CATALYST REGENERATION The conditions in the FCC catalyst regenerator are conventional. U.S. 4,116,814 (and many other patents) discuss regeneration conditions. Internal or external heat exchangers may be used to remove heat.
• Reactivation of additive catalyst, or conventional catalyst, with hydrogen or hydrogen-rich gas may be practiced herein. Operation with H 2 at 600-1400°F, preferably at 800-1200°F gives good results.
• Figure 1 shows integration of conventional FCC processing in one riser with FCC upgrading of resid, activated by microwave radiation, and with reactive fragment generation in a second riser.
• light hydrocarbon in line 4 enters a first FCC riser reactor 6 and combines with a hot regenerated catalyst, from a regenerator not shown, via conduit 8.
• Reactive fragments and catalyst pass up riser 6 and contact activated resid from line 13.
• Heated resid from line 9 passes through microwave heater 11 to become activated resid. The heated resid combines with the reactive fragments and catalyst and passes up riser 6.
• the microwaved resid contains reactive compounds which combine with reactive fragments of the light hydrocarbons in the riser.
• Riser 6 discharges into a riser cyclone 10 in reactor vessel 7.
• Cyclone 10 discharges catalyst down through a dipleg 14 into a catalyst bed 16.
• Catalyst is discharged via dipleg 44 into bed 16. Gas passes via outlet 42 to a plenum chamber 50, and line 52 to a conduit 160.
• the catalyst in bed 16 enters stripper 18 in a lower portion of reactor vessel 7. Catalyst passes down and countercurrently contacts stripping gas from line 20 and header 22. Optional trays (baffles) 24 may enhance contact. Stripped catalyst exits via conduit 30 and passes to the regenerator.
• Vacuum gas oil from line 102 and a heavy cycle oil recycle stream from line 174 pass via line 104 into a second, and conventional, FCC riser reactor 106.
• Hot regenerated catalyst, from a regenerator (not shown), is added to the base of the riser.
• Catalyst and feed pass through riser 106 and discharge into riser cyclone 110 in vessel 107.
• Catalyst is discharged via dipleg 114 to bed 116.
• Vapor exits via outlet into vessel 107.
• _> _ then passes into cyclone 140. Catalyst passes through dipleg - ⁇ 44 to bed 116. Vapor passes via line 142 to plenum chamber 150, line 152, and line* 160, where it combines with vapor from line 52, and enters fractionators 170.
• Bed 116 passes down through stripper 118 and countercurrently contacts stripping gas from line 120 and header 122. Trays 124 enhance stripping. Stripped catalyst passes via conduit 130 to a regenerator.
• Fractionators 170 comprising one or more towers or flash drums (not shown), separate hydrocarbons in line 160 into one or more light products in line 172, and a heavy cycle oil stream of 650°F (343°C ) liquid, which is recycled via line 174.
• the advantages of the Figure 1 embodiment of the invention include quick initial cracking of resid and separating the heaviest portion of the cracked resid and recycling it to a second riser reactor with a conventional feed, vacuum gas oil.
• the process enhances yields by alkylating activated resid with reactive light hydrocarbon fragments.
• the invention may also be practiced in a single riser FCC as shown in Figure 2.
• a light hydrocarbon enters a riser 206 via line 204 and combines with hot regenerated catalyst from conduit 208 to form reactive fragments.
• Resid in line 209 passes through microwave heater 211, is activated, and enters riser 206 via line 213 to combine with the catalyst and reactive light fragments.
• the resulting mixture passes up the riser, for a resid residence time of preferably less than 1 second, and contacts more regenerated catalyst and hydrocarbon from lines 203, 205 respectively.
• the hydrocarbons in line 205 are preferably vacuum gas oil from line 22 and recycled heavy cycle oil from line 274.
• the mixture continues up through riser 206 into riser cyclone 210 vessel 207.
• Cyclone 210 separates catalyst from vapor. Catalyst passes via dipleg 214 into bed 216. Vapor passes via outlet 212 into vessel 207. Vapor from vessel 207 enters cyclone 240 which recovers entrained catalyst which passes via dipleg 244 into bed 216. The vapor passes via outlet 242, plenum chamber 250, vessel outlet 252, and line 260 to separator 270. Separator 270 separates cracked products into a-lighter product stream 272, and a heavy cycle oil stream comprising 650°F (343°C ) hydrocarbons, recycled via line 205 into riser 206.
• the catalyst in bed 216 passes down through stripper 218 and contacts stripping gas from line 220 and header 222. Baffles 224 enhance stripping. Stripped catalyst exits vessel 218 via outlet 230 and passes to a regenerator, not shown.
• the invention shown in Figure 2 uses a single riser to react microwave-activated resid with light hydrocarbons fragments, and catalyst, before adding more catalyst, vacuum gas oil and recycle heavy cycle oil.
• the vacuum gas oil and recycled heavy cycle oil dilute the resid to minimize coking.
• the vacuum gas oil and cycle oil may also quench the riser as much as 300°F (167°C), preferably between 50° and 300°F (28° - 167°C) to minimize coking.
• riser 306 The activated resid and reactive fragments, react in riser 306.
• Riser 306 discharges into cyclone 310 in reactor vessel 307.
• Cyclone 310 discharges catalyst via dipleg 314 into bed 316.
• Vapor exits via outlet 312 into an atmosphere of vessel 307.
• Vapor leaves vessel 307 via a cyclone 340. Entrained catalyst is recovered and discharged via dipleg 414. Vapor passes via outlet 342, plenum chamber 350, and lines 352 and 360, to separator 370.
• Hot regenerated catalyst is added via conduit 408 to the riser.
• Riser 406 discharges into a riser cyclone 410 in vessel 307.
• Cyclone 410 discharges catalyst via dipleg 414 to bed 316.
• Vapor via exits outlet 412 into vessel 307.
• Vapor exits vessel 307 via cyclone 340, which recovers entrained catalyst and passes it via dipleg 344 to bed 316.
• the vapor passes through outlet 342 into plenum 350, outlet 352, and line.360, into separators 370.
• the catalyst in bed 316 passes down to stripper 318 and countercurrently contacts stripping gas from line 320 and header 322. Trays 334 enhance stripping. Stripped catalyst passes via outlet 330 to a regenerator (not shown).
• Figure 4 shows use of an elutriable catalyst mixture used in conjunction with an elutriating riser, an elutriating stripper, a reactivation zone, a resid feed and fragment generation.
• Riser reactor 410 receives C- and C, paraffins in lower region 411 through line 413 and stripped, reactivated catalyst via line 480 and valve 481.
• the stripped catalyst contains a lot of ZSM-5.
• Conditions in region 411 can be varied to maximize production of aromatics or light olefins, by varying the ZSM-5 content, and using fragment generation conditions previously discussed.
• a feed in line 401 is visbroken in visbreaker 402 and cascaded via line 415 into region 412 of riser 410 via line 415.
• the feed combines with the ascending catalyst-hydrocarbon vapor suspension from region 411. Addition of hot, regenerated conventional catalyst from the regenerator via conduit 460 and valve 461 permits some control of catalyst composition in region 412 and also some control of the temperature.
• the zeolite Y concentration is 2 to 50, most preferably 5 to 25 wt %.
• the temperature can be 482 to 621°C (900 to 1150°F) and preferably 496 to 566°C (925 to 1050°F).
• the preferred catalyst to visbroken feed ratio is 3:1 to 20:1 and most preferably 4:1 to 10:1.
• the visbroken feed combines with reactive fragments and also cracks in the riser to lower boiling products.
• the riser discharges into cyclone separator 414 which separates catalyst from gas. Catalyst is discharged via dipleg 420 into bed 422. Vapor enters plenum chamber 416.
• Descending catalyst bed 422 in an outer region of the stripper encounters stripping gas, e.g., steam, added via lines 427 and 428 which lifts the less dense particles of catalyst, e.g., the conventional catalyst, up concentrically arranged vertical lines 460 and 461 which lead to cyclones 470 and 471.
• stripping gas e.g., steam
• a light olefin feed e.g., a gas rich in ethylene and/or propylene
• the more dense particles, e.g., ZSM-5 additive catalyst flow down via conduit 465 to be reactivated and in vessel 450 with H 2 from line 451 then returned to riser 410.
• Figure 4 shows use of a dense, or less elutriable, additive it is also possible to reverse the relative settling rates and use an additive which is less dense than the conventional catalyst. In that case the additive will be removed overhead in the stripper.
• a dual riser FCC unit with a slightly different configuration is used.
• a conventional feed contacts a conventional catalyst (it may also contain a minor amount of additive rich in ZSM-5) from a conventional FCC regenerator in the base of a conventional FCC riser reactor which discharges into a cyclone separator within a vessel.
• an elutriable mixture of conventional catalyst and additive catalyst rich in ZSM-5, and with a faster settling rate than the conventional catalyst
• a light H 2 ⁇ rich gas form reactive fragments in the base of the riser.
• the base of the riser preferably has an enlarged diameter lower portion, which results in lower superficial vapor velocities in the base of the riser than in the top of the riser.
• the settling velocity of the additive catalyst approaches the superficial vapor velocity in the bottom of the riser. This results in a longer residence time for the additive catalyst, rich in ZSM-5, in the base of the riser.
• Additional hot regenerated catalyst, and activated heavy feed such as visbroken or microwaved resid, are added about half way up the second riser.
• the activated resid reacts readily with the reactive fragments generated in the base of the riser.
• the riser preferably discharges into a cyclone which removes vapor overhead and discharges catalyst via a dipleg into an elutriating catalyst stripper, such as that shown in Figure 4.
• Conventional catalyst is lifted out of the central stripper by the stripping gas.
• the heavier, or less elutriable, additive catalyst passes down through the stripper and is recycled to the base of the elutriating riser, as previously discussed.
• the conventional catalyst, displaced from the central region by stripping gas preferably flows into an auxiliary stripper, and then to conventional regeneration.
• a single-riser FCC operates with multiple feed-point injection.
• a light preferably olefins hydrogen-rich stream, which contacts hot regenerated catalyst to form reactive fragments.
• the fragment-catalyst mixture passes up the riser and contacts freshly visbroken resid.
• the resulting mixture passes up the riser and contacts additional hot regenerated catalyst.
• a conventional gas oil feed is added at about the midpoint of the riser.
• a mixed catalyst system comprising a conventional FCC catalyst and a shape selective zeolite additive, such as ZSM-5, is used.
• an elutriatable additive When an elutriatable additive is used, it is beneficial to provide an elutriating riser, i.e. an unusually wide portion of the riser at either the base or the top of the riser. It is also beneficial, when ' an elutriable catalyst mixture is used, to provide an elutriating catalyst stripper.
• the catalyst stripper may separate additive from conventional catalyst by sieving or by relying on differences in settling velocity.
• Catalyst may be reactivated prior to use. This is especially advantageous when a shape selective zeolite additive catalyst is used.
• shape selective additive after stripping, may be charged to a reactivation zone for contact with a reactivation gas such as hydrogen, prior to re-use in the FCC riser.
• the experiments are based on laboratory tests. The tests roughly simulated severe visbreaking immediately followed by catalytic cracking.
• the severe visbreaking FCC process was simulated by heating the feed to 1100°F for 2-5 seconds and then immediately passing this over cracking catalysts at 960°F in a fixed-fluidized bed reactor.
• the test is reliable for predicting most product yields and octane number of product but is not as reliable for predicting coke yields. There is probably laminar flow in some portions of the preheater, and coking rapidly occurs in such conditions. In commercial units, this is not a problem because velocities through the furnace tubes are higher.
• the FCC reactor was a conventional, pilot plant fixed-fluidized bed reactor.
• the FCC catalyst given I.D.# F19260 used was a commercially available catalyst, and had the following properties:
• the catalyst was steam deactived at 788°C (1450°F) for ten hours in an atmosphere of 45% steam and 55% air to simulate commercial aging.
• the properties shown are for fresh catalyst, while what was actually used was steam deactivated.
• A Alkylate made by alkylating olefins with isobutane
• the yields and octane, etc. reported above are based on the average of four runs at slightly different conversions. There were four runs of the base case, and the conversions were all around 70%. The data were graphed as a function of the % conversion, and the results at 70% conversion used to generate the table. Four runs were also conducted at 1100°F preheater temperature, and four runs at 980°F reactor temperature.
• the severity of visbreaking at 593°C, 1100°F in the pretreater can be estimated. Based on the residence time of the liquid feed in the pretreater of 2-5 seconds. The reaction severity was 606 to 1515 ERT. Conventional correlations used to calculate reaction severities in visbreakers and cokers were used, however, the temperature in the preheater was quite a bit higher than that in conventional visbreaking operation. It Is also difficult to accurately calculate the residence time of small amounts of liquid in a small preheater operated at such a high temperature. Accordingly, there Is a good deal of uncertainty about the severity of the pretreatment step.
• the reactor preheater was "regenerated” by burning off the carbon in the preheater and absorbing C0 ? in the flue gas, in a scrubber. From the C0 2 yields, the amount of coke deposited in the preheater could be determined, and the plant material balance could be re-calculated to account for this. When this was done, as shown in the following table, the yields changed. The G+A yields are now about the same whether the preheat temperature is 960°F or 1100°F, and coke yields get worse with an 593°C (1100°F) higher preheat temperature. The gasoline octane number advantage from resid activation remains.
• Yields are recalculated from initial yields to reflect coke deposition in the preheater.
• the above yields and weight balances are based on a single test (Of 960°F) compared to a single test (at 1100°F). The data could be adjusted to a constant 70% conversion, but this was not done.
• the process of the present invention will work especially well in an FCC unit with additive catalysts, such as ZSM-5, which make very little coke, in addition to conventional FCC catalyst.
• Use of a catalyst with perhaps 5-10% conventional, large pore zeolite and 5-10 wt %, preferably 2-10 wt % ZSM-5 zeolite may be the ideal catalyst for use in upgrading severely visbroken feed.
• Elutriating risers, elutriating strippers, etc. which can increase the residence time of ZSM-5 additive in the riser and minimize the residence time of the ZSM-5 in the regenerator could also be beneficial.
• the invention has been discussed in relation to the combination visbreaking-FCC, it can be used in many other ways.
• Activation pretreatment of resid will render resid more amenable to conventional hydrotreating and hydrocracking processes.
• Alternative pretreatment procedures can also be used, e.g., tunable microwaves, lasers, and the like, provided they make resid feed as reactive as a corresponding thermal pretreatment.

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