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
  • C10G51/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more cracking processes only
  • C10G51/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more cracking processes only plural serial stages only
  • C10G51/026—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more cracking processes only plural serial stages only only catalytic cracking steps
• • 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
  • C10G11/182—Regeneration
• • 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
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/10—Feedstock materials
  • C10G2300/1037—Hydrocarbon fractions
  • C10G2300/104—Light gasoline having a boiling range of about 20 - 100 °C
• • 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
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/20—C2-C4 olefins
• • 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
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/22—Higher olefins
• • 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
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/30—Aromatics

Definitions

• the present invention generally relates to methods of producing light olefins and aromatic hydrocarbons. More specifically, the present invention relates to a method of producing light olefins and aromatic hydrocarbons using two fluid catalytic cracking units.
• Light olefins (C2 and C3 olefins) are building blocks for many chemical processes. Light olefins are used to produce polyethylene, polypropylene, ethylene oxide, ethylene chloride, propylene oxide, and acrylic acid, which, in turn, are used in a wide variety of industries such as the plastic processing, construction, textile, and automotive industries. Generally, light olefins are produced by steam cracking naphtha and dehydrogenation of paraffin.
• Aromatics such as BTX (benzene, toluene, and xylene) are used in many different areas of chemical industry, especially the plastic and polymer sectors.
• BTX benzene, toluene, and xylene
• benzene is a precursor for producing polystyrene, phenolic resins, polycarbonate, and nylon.
• Toluene is used for producing polyurethane and as a gasoline component.
• Xylene is feedstock for producing polyester fibers and phthalic anhydride.
• benzene, toluene, and xylene are conventionally produced by catalytic reforming of naphtha.
• Fluid catalytic cracking of light naphtha stream is capable of producing both light olefins and BTX.
• light olefins are cracked in a fluidized bed reactor under high reaction temperature (above 600 °C) with a relatively short residence time to overcome the endothermicity of the reactions and oligomerization of light olefins.
• the effluent is separated to recover light olefins and aromatics.
• the overall selectivity from light naphtha to light olefins and aromatics is limited.
• a solution to at least some of the above-mentioned problems associated with the production process for light olefins and aromatics has been discovered.
• the solution resides in a method and a system that involves processing light naphtha with two fluid catalytic cracking units in series.
• the effluent from the first fluid catalytic cracking unit can be fractionated to form a stream comprising primarily C 4 to C6 hydrocarbons and/or a stream comprising primarily Cs to C12 hydrocarbons, which can be fed to the second fluid catalytic cracking unit under reaction conditions optimized for producing light olefins and/or aromatics (e.g BTX), respectively.
• the reaction conditions in the second fluid catalytic cracking unit can be optimized for converting C 4 to C6 hydrocarbons to light olefins and/or converting C5 to C12 hydrocarbons to aromatics, resulting in improved productivity of olefins and aromatics. Therefore, the methods of the present invention provide a technical advantage over at least some of the problems associated with the currently available methods for producing light olefins and aromatics mentioned above.
• Embodiments of the invention include a method of producing olefins and aromatics.
• the method comprises feeding a light naphtha stream to a first catalyst riser of a fluid catalytic cracking (FCC) unit.
• the light naphtha stream has an initial boiling point in a range 15 to 40 °C and a final boiling point (FBP) in the range 65 to 350 °C.
• the method further comprises contacting the light naphtha stream with a first catalyst in the first catalyst riser under reaction conditions sufficient to crack Cs to Ci hydrocarbons of the light naphtha stream and form a first cracked stream.
• the method further comprises fractionating the first cracked stream to produce a plurality of streams that comprise a first stream comprising primarily C 4 to C6 hydrocarbons.
• the method further still comprises flowing the first stream to a second riser of the FCC unit.
• the method further comprises contacting the first stream with a second catalyst in the second catalyst riser under reaction conditions sufficient to crack C 4 to C6 hydrocarbons of the first stream to form a second cracked stream comprising C2 to C3 olefins.
• the first catalyst and the second catalyst are different and the reaction conditions in the first catalyst riser are adapted such that the yield of light olefins from C5 to C7 hydrocarbons is 20 to 60 wt.% and the yield of aromatics from C5 to C7 hydrocarbons is 3 to 20 wt.%.
• the method further still comprises regenerating the first catalyst and the second catalyst separately.
• Embodiments of the invention include a method of producing olefins and aromatics.
• the method comprises feeding a light naphtha stream to a first catalyst riser of a fluid catalytic cracking (FCC) unit.
• the light naphtha stream has an initial boiling point in a range 15 to 40 °C and a final boiling point (FBP) in the range 65 to 350 °C.
• the method further comprises contacting the light naphtha stream with a first catalyst in the first catalyst riser under reaction conditions sufficient to crack C5 to C7 hydrocarbons of the light naphtha stream and form a first cracked stream.
• the method further comprises fractionating the first cracked stream to produce a first stream comprising primarily C 4 to C6 hydrocarbons, a second stream comprising primarily C2 and C3 olefins, a third stream comprising primarily benzene, toluene, and xylene, collectively, and a fourth stream comprising dry gas.
• the method further comprises flowing the first stream to a second catalyst riser of the FCC unit.
• the method further still comprises contacting the first stream with a second catalyst in the second catalyst riser under reaction conditions sufficient to crack C 4 to C6 hydrocarbons of the first stream to form a second cracked stream comprising C2 to C 4 olefins.
• the first catalyst and the second catalyst are different.
• the reaction conditions in the first catalyst riser are adapted such that the yield of light olefins from C5 to C7 hydrocarbons is 20 to 60 wt.% and the yield of aromatics from C5 to C7 hydrocarbons is 3 to 20 wt.%.
• the reaction conditions in the second catalyst riser are adapted such that the yield of C2 and C 3 hydrocarbons from C 4 and C6 hydrocarbons is 0 to 70 wt.%.
• the method further comprises regenerating the first catalyst and the second catalyst separately.
• Embodiments of the invention include a method of producing olefins and aromatics. The method comprises feeding a light naphtha stream to a first catalyst riser of a fluid catalytic cracking (FCC) unit.
• FCC fluid catalytic cracking
• the light naphtha stream has an initial boiling point in a range 15 to 40 °C and a final boiling point (FBP) in the range 65 to 350 °C.
• the method further comprises contacting the light naphtha stream with a first catalyst in the first catalyst riser under reaction conditions sufficient to crack Cs to Ci hydrocarbons of the light naphtha stream and form a first cracked stream.
• the method further comprises fractionating the first cracked stream to produce a plurality of streams that comprises a heavy processing stream comprising primarily Cs to C12 hydrocarbons.
• the method further still comprises flowing the heavy processing stream to a second catalyst riser of the FCC unit.
• the method further comprises contacting the heavy processing stream with a second catalyst in the second catalyst riser under reaction conditions sufficient to crack C5 to C12 hydrocarbons of the heavy processing stream to form a second cracked stream comprising aromatics.
• the first catalyst and the second catalyst are different.
• the reaction conditions in the first catalyst riser are adapted such that yield of light olefins from C5 to C7 hydrocarbons to olefins is 20 to 60 wt.% and yield of aromatics from the C5 to C7 hydrocarbons to aromatics is 3 to 20 wt.%.
• the reaction conditions in the second catalyst riser are adapted such that yield of aromatics from C5 to C12 nonaromatic hydrocarbons is 5 to 50 wt.%.
• the method further still comprises regenerating the first catalyst and the second catalyst separately.
• the terms“wt.%”,“vol.%” or“mol.%” refer to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of the material is 10 mol.% of component.
• n is a positive integer, e.g. 1, 2, 3, 4, or
• dry gas as that term is used in the specification and/or claims, means a gas stream comprising primarily methane and hydrogen, collectively, and less than 5 wt.% of water.
• yield means the percentage of actual amount of product produced over theoretical amount of product that can be produced based on stoichiometry.
• “primarily” may include 50.1 wt. % to 100 wt. % and all values and ranges there between, 50.1 mol. % to 100 mol. % and all values and ranges there between, or 50.1 vol. % to 100 vol. % and all values and ranges there between.
• the term“riser,” as that term is used in the specification and/or claims, means a reactor or a reaction zone, in which fluid and solids move upward substantially concurrently.
• FIG. 1A shows a schematic diagram for a system of producing light olefins and aromatics optimized for high light olefins productivity, according to embodiments of the invention
• FIG. 1B shows a schematic diagram for a system of producing light olefins and aromatics optimized for high aromatics productivity, according to embodiments of the invention.
• FIG. 2 shows a schematic flowchart for a method of producing light olefins and aromatics, according to embodiments of the invention.
• the solution is premised on a method including using a second fluid catalytic cracking unit to further crack the C 4 to C6 and/or Cs to C12 hydrocarbons from the effluent of the first catalyst riser to form additional light olefins and/or aromatics with high yields, resulting in improved overall productivity and energy efficiency.
• the system for producing light olefins and aromatics can include a system comprising two catalyst risers of a fluid catalytic cracking unit and a fractionation unit shared by the two catalyst risers.
• FIG. 1A a schematic diagram is shown of system 100 that is capable of processing a light naphtha stream to produce light olefins C2 and C3 olefins and aromatics with improved overall selectivity and production efficiency compared to conventional fluid catalytic cracking process.
• System 100 may be optimized for light olefins production.
• system 100 includes first catalyst riser 101 of a fluid catalytic cracking (FCC) unit configured to receive and catalytically crack light naphtha stream 11 to produce first cracked stream 12.
• FCC fluid catalytic cracking
• first cracked stream 12 may include light olefins, aromatics, dry gas, and C 4 to C12 hydrocarbons.
• First cracked stream 12 may further include gasoline.
• first catalyst riser 101 may include a first fluidized bed reactor.
• the first fluidized bed reactor may contain a first catalyst configured to catalyze the cracking reaction of light naphtha stream 11 to produce cracked stream 12.
• the first catalyst may include a single phase catalyst and/or multi-phase catalyst.
• the first catalyst includes at least one component of an acidic porous zeolite.
• the first catalyst may be a medium pore or large pore catalyst.
• Non-limiting examples of the first catalyst may include Mordenite Framework Inverted (MFI), Faujasite (FAU), Mordenite (MOR), Beta, Omega structure type zeolites and combinations thereof.
• the first catalyst may include a Si/Al ratio in a range of above 20.
• the first catalyst may be a medium pore or large pore catalyst.
• the first catalyst may have a surface area in a range of 50 to 500 m 2 /g and all ranges and values there between including ranges of 50 to 75 m 2 /g, 75 to 100 m 2 /g, 100 to 125 m 2 /g, 125 to 150 m 2 /g, 150 to 175 m 2 /g, 175 to 200 m 2 /g, 200 to 225 m 2 /g, 225 to 250 m 2 /g, 250 to 275 m 2 /g, 275 to 300 m 2 /g, 300 to 325 m 2 /g, 325 to 350 m 2 /g, 350 to 375 m 2 /g, 375 to 400 m 2 /g, 400 to 425 m 2 /g, 425 to 450 m 2 /g, 450
• fractionator 102 may include a distillation column, an acid wash unit, a base wash unit, a solvent extraction unit, or combinations thereof.
• fractionator 102 may be configured to separate first cracked stream 12 to form first stream l5a comprising primarily C 4 to C6 hydrocarbons, light olefins stream 14 (a second stream), aromatic stream 16 comprising primarily BTX, and dry gas stream 13 (the fourth stream) comprising primarily methane and hydrogen, collectively and, in some embodiments, heavy stream 17 (bottom stream) comprising primarily C12+ hydrocarbons.
• dry gas stream 13 may include less than 5 wt.% water.
• a first outlet of fractionator 102 may be in fluid communication with second catalyst riser 103 of a fluid catalytic cracking unit such that first stream l5a flows from fractionator 102 to second catalyst riser 103.
• second catalyst riser 103 may be configured to receive and catalytically crack first stream l5a to produce second cracked stream l8a comprising light olefins (C2 and C3 olefins) and/or aromatics.
• second cracked stream l8a may include 5 to 50 wt.% light olefins and all ranges and values there between including ranges of 5 to 10 wt.%, 10 to 15 wt.%, 15 to 20 wt.%, 20 to 25 wt.%, 25 to 30 wt.%, 30 to 35 wt.%, 35 to 40 wt.%, 40 to 45 wt.%, and 45 to 50 wt.%.
• second catalyst riser 103 comprises a fluidized bed reactor containing a second catalyst. The second catalyst may be different from the first catalyst. Differences between the first catalyst and the second catalyst may include but are not limited to Si to Al ratio, topology (i.e., medium pore size or large pore size), surface area, promoter, post production treatment of the catalysts, and combinations thereof.
• fractionator 103 may be in fluid communication with an inlet of fractionator 102 such that second cracked stream l8a flows from second riser to fractionator 102.
• Fractionator 102 may be further configured to separate second cracked stream l8a to produce additional light olefins (C2 and C3 olefins) and/or additional aromatics (primarily BTX).
• an outlet of fractionator 102 may be in fluid communication with first catalyst riser 101 and/or second catalyst riser 103 such that heavy stream 17 (bottom stream) flows from fractionator 102 to first catalyst riser 101 and/or second catalyst riser 103.
• fractionator may be configured to separate first cracked stream 12 to form heavy processing stream 15b comprising primarily C5 to C12 hydrocarbons, light olefins stream 14 (a second stream), aromatic stream 16 comprising primarily BTX, and dry gas stream 13 (the fourth stream) comprising primarily methane and hydrogen, collectively and optionally heavy stream 17 comprising primarily C12+ hydrocarbons.
• fractionator 102 may be configured to further produce light recycling stream 19 comprising primarily C 4 to C6 hydrocarbons.
• An outlet of fractionator 102 may be in fluid communication with an inlet of first catalyst riser 101 such that light recycling stream 19 flows from fractionator 102 to first catalyst riser 101.
• system 100' as shown in FIG. 1B may be optimized for aromatics production.
• second catalyst riser 103 may be adapted to catalytically crack heavy processing stream 15b to produce second cracked heavy stream 18b (cracked processing stream) comprising primarily aromatics and/or light olefins.
• second cracked heavy stream 18b may include 5 to 60 wt.% aromatics and all ranges and values there between including ranges of 5 to 10 wt.%, 10 to 15 wt.%, 15 to 20 wt.%, 20 to 25 wt.%, 25 to 30 wt.%, 30 to 35 wt.%, 35 to 40 wt.%, 40 to 45 wt.%, 45 to 50 wt.%, 50 to 55 wt.%, and 55 to 60 wt.%.
• first catalyst riser 101 and/or second catalyst riser 103 may be replaced by a first downflow reactor and/or a second downflow reactor, respectively. Overall, configuration of system 100' as shown in FIG.
• 1B is the same as system 100 as shown in FIG. 1A except the compositions of the streams (first stream l5a and heavy stream 15b) from fractionator 102 to second riser 103, the compositions of streams (second cracked stream l8a and second cracked heavy stream 18b) flowing from second riser 103 to fractionator 102, and light recycling stream 19 only in system 100'.
• embodiments of the invention include method 200 for producing light olefins and aromatics.
• Method 200 may be implemented by system 100 and/or system 100' as shown in FIG. 1 A and FIG. 1B, respectively.
• method 200 may include feeding light naphtha stream 11 to first catalyst riser 101 of a fluid catalytic cracking (FCC) unit.
• FCC fluid catalytic cracking
• light naphtha stream has an initial boiling point (IBP) in a range of 15 to 40 °C and all ranges and values there between including ranges of 15 to 20 °C, 20 to 25 °C, 25 to 30 °C, 30 to 35 °C, and 35 to 40 °C.
• IBP initial boiling point
• Light naphtha stream 11 may have a final boiling point (FBP) in a range of 65 to 350 °C and all ranges and values there between including ranges of 65 to 80 °C, 80 to 95 °C, 95 to 110 °C, 110 to 125 °C, 125 to 140 °C, 140 to 155 °C, 155 to 170 °C, 170 to 185 °C, 185 to 200 °C, 200 to 215 °C, 215 to 230 °C, 230 to 245 °C, 245 to 260 °C, 260 to 275 °C, 275 to 290 °C, 290 to 305 °C, 305 to 320 °C, 320 to 335 °C, and 335 to 350 °C.
• FBP final boiling point
• light naphtha stream 11 contains
• method 200 further comprises contacting light naphtha stream 11 with the first catalyst in first catalyst riser 101 under reaction conditions sufficient to crack Cs to Ci hydrocarbons of light naphtha stream 11 and form first cracked stream 12, as shown in block 202.
• the reaction conditions in first catalyst riser 101 at block 202 are adapted such that the yield of light olefins from Cs to Ci hydrocarbons is 5 to 50 wt.% and the yield of aromatics from Cs to Ci hydrocarbons is 5 to 30 wt.%.
• reaction conditions in first catalyst riser 101 may include a reaction temperature in a range of 600 to 720 °C and all ranges and values there between including ranges of 600 to 610 °C, 610 to 620 °C, 620 to 630 °C, 630 to 640 °C, 640 to 650 °C, 650 to 660 °C, 660 to 670 °C, 670 to 680 °C, 680 to 690 °C, 690 to 700 °C, 700 to 710 °C, and 710 to 720 °C.
• the reaction conditions in first catalyst riser 101 may further include a reaction pressure in a range of 14 to 73 psi and all ranges and values there between including ranges of 14 to 16 psi, 16 to 19 psi, 19 to 22 psi, 22 to 25 psi, 25 to 28 psi, 28 to 31 psi, 31 to 34 psi, 34 to 37 psi, 37 to 40 psi, 40 to 43 psi, 43 to 46 psi, 46 to 49 psi, 49 to 52 psi, 52 to 55 psi, 55 to 58 psi, 58 to 61 psi, 61 to 64 psi, 64 to 67 psi, 67 to 70 psi, and 70 to 73 psi.
• the weight hourly space velocity in first catalyst riser 101 may be in a range 0.5 to 30 hr 1 .
• the residence time in first catalyst riser 101 may be in a range of 1 to 10 s and all ranges and values there between including 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, and 9 s.
• the catalyst-to-oil ratio (C/O ratio) in the fluidized bed of first catalyst riser 101 may be in a range of 10 to 80 and all ranges and values there between including ranges of 10 to 15, 15 to 20, 20 to 25, 25 to 30, 30 to 35, 35 to 40, 40 to 45, 45 to 50, 50 to 55, 55 to 60, 60 to 65, 65 to 70, 70 to 75, and 75 to 80.
• light naphtha stream 11 may further include steam with a steam to hydrocarbon ratio of 0 to 0.5 and all ranges and values there between including ranges of 0 to 0.05, 0.05 to 0.10, 0.10 to 0.15, 0.15 to 0.20, 0.20 to 0.25, 0.25 to 0.30, 0.30 to 0.35, 0.35 to 0.40, 0.40 to 0.45, and 0.45 to 0.50.
• Light naphtha stream 11 may further still include dry gas comprising primarily methane and hydrogen, collectively. The dry gas may be used as a fluidization medium in first catalyst riser 101 and/or second catalyst riser 103.
• the ratio of dry gas to hydrocarbon in light naphtha stream 11 may be in a range of 0 to 0.5 and all ranges and values there between including ranges of 0 to 0.05, 0.05 to 0.10, 0.10 to 0.15, 0.15 to 0.20, 0.20 to 0.25, 0.25 to 0.30, 0.30 to 0.35, 0.35 to 0.40, 0.40 to 0.45, and 0.45 to 0.50.
• first cracked stream 12 may include 5 to 50 wt.% light olefins and 5 to 35 wt.% aromatics (BTX).
• method 200 further comprises, in fractionator 102, fractionating first cracked stream 12 to produce a plurality of streams that comprises first stream l5a comprising primarily C 4 to C6 hydrocarbons.
• first stream l5a comprises 50 to 100 wt.% C 4 to C6 hydrocarbons.
• first cracked stream 12 may be fractionated to produce a plurality of streams including heavy processing stream 15b instead of first stream l5a.
• Heavy processing stream 15b comprises primarily Cs to C12 hydrocarbons. Heavy processing stream 15b may comprise 50 to 100 wt.% C5 to C12 hydrocarbons and all ranges and values there between.
• the plurality of streams further comprises light olefin stream 14 (the second stream) comprising primarily C2 to C 4 olefins, aromatic stream 16 (the third stream) comprising primarily BTX, and dry gas stream 13 (the fourth stream) comprising primarily methane and hydrogen, collectively, and optionally heavy stream 17 comprising primarily C12+ hydrocarbons.
• fractionating the first cracked stream 12 further produces light recycling stream 19 comprising primarily C 4 to C6 hydrocarbons. Light recycling stream 19 may be flowed from fractionator 102 back to first catalyst riser 101.
• method 200 further comprises flowing first stream l5a to second catalyst riser 103 of the FCC unit. As shown in block 205a, method 200 may further still include contacting first stream l5a with the second catalyst in second catalyst riser 103 under reaction conditions sufficient to crack C 4 to C6 hydrocarbons of first stream l5a to form second cracked stream l8a comprising C2 to C 4 olefins.
• second cracked stream l8a may include 5 to 50 wt.% light olefins and all ranges and values there between including 5 to 10 wt.%, 10 to 15 wt.%, 15 to 20 wt.%, 20 to 25 wt.%, 25 to 30 wt.%, 30 to 35 wt.%, 35 to 40 wt.%, 40 to 45 wt.%, and 45 to 50 wt.%.
• second cracked stream may further include aromatics.
• reaction conditions of second catalyst riser 103 in block 205a are adapted such that the yield of light olefins from C 4 to C6 hydrocarbons of first stream l5a is from 0 to 70% and the yield of aromatics from C 4 to C6 hydrocarbons of first stream l5a is from 5 to 30%.
• the reaction conditions at block 205a may include a reaction temperature in a range of 500 to 700 °C and all ranges and values there between including ranges of 500 to 510 °C, 500 to 510 °C, 510 to 520 °C, 520 to 530 °C, 530 to 540 °C, 540 to 550 °C, 550 to 560 °C, 560 to 570 °C, 570 to 580 °C, 580 to 590 °C, 590 to 600 °C, 600 to 610 °C, 610 to 620 °C, 620 to 630 °C, 630 to 640 °C, 640 to 650 °C, 650 to 660 °C, 660 to 670 °C, 670 to 680 °C, 680 to 690 °C, and 690 to 700 °C,.
• the reaction conditions in block 204 may further include reaction pressure in a range of 14 to 73 psi and all ranges and values there between between including ranges of 14 to 16 psi, 16 to 19 psi, 19 to 22 psi, 22 to 25 psi, 25 to 28 psi, 28 to 31 psi, 31 to 34 psi, 34 to 37 psi, 37 to 40 psi, 40 to 43 psi, 43 to 46 psi, 46 to 49 psi, 49 to 52 psi, 52 to 55 psi, 55 to 58 psi, 58 to 61 psi, 61 to 64 psi, 64 to 67 psi, 67 to 70 psi, and 70 to 73 psi.
• a weight hourly space velocity in block 205a may be in a range of 5 to 30 hr 1 and all ranges and values there between including ranges of 5 to 9 hr 1 , 9 to 12 hr 1 , 12 to 15 hr 1 , 15 to 18 hr 1 , 18 to 21 hr 1 , 21 to 24 hr 1 , 24 to 27 hr 1 , and 27 to 30 hr 1 .
• a residence time of second catalyst riser 103 in block 204a may be in a range of 1 to 10 s and all ranges and values there between including 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, and 9 s..
• the catalyst-to-oil ratio of the fluidized bed in second riser at block 205a may be in a range of 10 to 80 and all ranges and values there between including ranges of 10 to 15, 15 to 20, 20 to 25, 25 to 30, 30 to 35, 35 to 40, 40 to 45, 45 to 50, 50 to 55, 55 to 60, 60 to 65, 65 to 70, 70 to 75, and 75 to 80.
• the second catalyst is different from the first catalyst.
• second cracked stream l8a is fractionated in fractionator 102 to separate additional light olefins and/or aromatics.
• heavy processing stream 15b instead of first stream l5a may be flowed to second catalyst riser 103 of the FCC unit.
• method 200 may further include contacting heavy processing stream 15b with the second catalyst in second catalyst riser 103 under reaction conditions sufficient to crack Cs to C12 hydrocarbons of the heavy processing stream to form second cracked heavy stream 18b comprising aromatics.
• second cracked heavy stream 18b may comprise 5 to 60 wt.% aromatics.
• second cracked heavy stream 18b may further include light olefins.
• reaction conditions in second catalyst riser 103 at block 205b are adapted such that the yield of aromatics from C5 to C12 nonaromatic hydrocarbons is 5 to 60 wt.% and the yield of light olefins from C5 to C12 nonaromatic hydrocarbons is 5 to 30 wt.%.
• reaction conditions in second riser at block 205b may include a reaction temperature in a range of 500 to 700 °C and all ranges and values there between.
• the reaction conditions in block 204 may further include reaction pressure in a range of 14 to 73 psi and all ranges and values there between.
• a weight hourly space velocity in block 205b may be in a range of 0.5 to 30 hr 1 and all ranges and values there between.
• the catalyst-to-oil ratio (C/O ratio) of the fluidized bed in second catalyst riser 103 at block 205b may be in a range of 10 to 80 and all ranges and values there between.
• a residence time of second catalyst riser 103 in block 205b may be in a range of 1 to 10 s and all ranges and values there between.
• the second catalyst in second catalyst riser 103 is different from the first catalyst in first catalyst riser 101.
• second cracked heavy stream 18b is fractionated in fractionator 102 to separate additional aromatics and/or light olefins.
• method 200 may further still include regenerating the first catalyst and the second catalyst separately, as shown in block 206.
• the first catalyst and the second catalyst may be regenerated in the same regenerator.
• the regenerating conditions may include a regeneration temperature in a range of 650 to 900 °C and all ranges and values there between including ranges of 650 to 660 °C, 660 to 680 °C, 680 to 700 °C, 700 to 720 °C, 720 to 740 °C, 740 to 760 °C, 760 to 780 °C, 780 to 800 °C, 800 to 820 °C, 820 to 840 °C, 840 to 860 °C, 860 to 880 °C, and 880 to 900 °C.
• the regenerating at block 206 may include adding an additional stream of hydrocarbon (light or/and heavy) to maintain heat balance.
• method 200 may include flowing a coke precursor in first catalyst riser 101 and/or second catalyst riser 103 to form coke on the first catalyst and/or second catalyst.
• the formed coke may be burnt in the regenerating at block 206 to provide heat to the first catalyst and/or second catalyst.
• Light straight run naphtha was processed in a pilot fluid catalytic cracking unit, which included two risers in series.
• the catalyst in both risers included ZSM-5 based catalyst.
• the reaction conditions in the first riser include a reaction temperature of 675 °C, a reaction pressure of 38 psia, a feed flow rate of 3.96 g/min, steam flow rate of 0.1 g/min, and a catalyst-to-oil ratio (C/O ratio) of 60.
• the reaction conditions in the second riser included substantially the same reaction temperature, reaction pressure, feed flow rate, and steam flow rate as the first riser.
• the catalyst-to-oil ratio in the second riser was 61.86.
• Embodiment 1 is a method of producing olefins and aromatics.
• the method includes feeding a light naphtha stream to a first catalyst riser of a fluid catalytic cracking (FCC) unit, the light naphtha stream having an initial boiling point (IBP) in a range 15 to 40 °C and a final boiling point (FBP) in a range 65 to 350 °C, then contacting the light naphtha stream with a first catalyst in the first catalyst riser under reaction conditions sufficient to crack Cs to Ci hydrocarbons of the light naphtha stream and form a first cracked stream.
• FCC fluid catalytic cracking
• the method further includes fractionating the first cracked stream to produce a plurality of streams that includes a first stream containing primarily C 4 to C6 hydrocarbons and flowing the first stream to a second catalyst riser of the FCC unit.
• the method also includes contacting the first stream with a second catalyst in the second catalyst riser under reaction conditions sufficient to crack C 4 to C6 hydrocarbons of the first stream to form a second cracked stream containing C2 to C3 olefins, wherein the first catalyst and the second catalyst are different and wherein the reaction conditions in the first catalyst riser are adapted such that yield of light olefins from C5 to C7 hydrocarbons is 20 to 60 wt.% and yield of aromatics from C5 to C7 hydrocarbons is 3 to 20 wt.%.
• the method includes regenerating the first catalyst and the second catalyst separately.
• Embodiment 2 is the method of embodiment 1, wherein the fractionating of the first cracked stream further produces a second stream containing primarily C2 to C3 olefins, a third stream containing primarily benzene, toluene, and xylene, collectively, and a fourth stream containing dry gas.
• Embodiment 3 is the method of embodiment 2, wherein the fractionating further produces a bottom stream containing C12+ hydrocarbons.
• Embodiment 4 is the method of embodiment 3, wherein the bottom stream is recycled back to the first catalyst riser.
• Embodiment 5 is the method of any of embodiments 2 to 4, wherein the dry gas is used as fluidization medium in the first catalyst riser and/or the second catalyst riser.
• Embodiment 6 is the method of any of embodiments 1 to 5, wherein the reaction conditions in the second catalyst riser are adapted such that the yield of light olefins from C 4 to C6 hydrocarbons is 0 to 90 wt.%.
• Embodiment 7 is the method of any of embodiments 1 to 6, wherein the first catalyst and/or the second catalyst contains an acidic porous zeolite including Mordenite Framework Inverted (MFI), Faujasite (FAET), Mordenite (MOR), Beta, Omega structure type zeolites.
• MFI Mordenite Framework Inverted
• FAET Faujasite
• MOR Mordenite
• Beta Omega structure type zeolites.
• Embodiment 8 is the method of any of embodiments 1 to 7, wherein the first catalyst and the second catalyst are different in parameters including silicon to aluminum ratio, pore size, surface area, promotor, or combinations thereof.
• Embodiment 9 is the method of any of embodiments 1 to 8, wherein the reaction conditions in the first catalyst riser include a reaction temperature of 600 to 720 °C, a steam to hydrocarbon ratio of 0 to 0.5, and dry gas to hydrocarbon ratio of 0 to 0.5.
• Embodiment 10 is the method of any of embodiments 1 to 9, wherein the reaction conditions in the second catalyst riser include a reaction temperature of 600 to 720 °C, a steam to hydrocarbon ratio of 0 to 0.5, and dry gas to hydrocarbon ratio of 0 to 0.5.
• Embodiment 11 is a method of producing olefins and aromatics.
• the method includes feeding a light naphtha stream to a first catalyst riser of a fluid catalytic cracking (FCC) unit, the light naphtha stream having an initial boiling point in a range 15 to 40 °C and a final boiling point (FBP) in a range 65 to 350 °C, then contacting the light naphtha stream with a first catalyst in the first catalyst riser under reaction conditions sufficient to crack Cs to Ci hydrocarbons of the light naphtha stream and form a first cracked stream.
• FCC fluid catalytic cracking
• the method also includes fractionating the first cracked stream to produce a plurality of streams that includes a hydrocarbon processing stream containing primarily Cs to C12 hydrocarbons and flowing the hydrocarbon processing stream to a second catalyst riser of the FCC unit. Further, the method includes contacting the hydrocarbon processing stream with a second catalyst in the second catalyst riser under reaction conditions sufficient to crack C5 to C12 hydrocarbons of the hydrocarbon processing stream to form a second cracked processing stream containing aromatics, wherein the first catalyst and the second catalyst are different and wherein the reaction conditions in the first catalyst riser are adapted such that yield of light olefins from C5 to C7 hydrocarbons is 5 to 35 wt.% and yield of aromatics from C5 to C7 hydrocargons is 5 to 50 wt.% and wherein the reaction conditions in the second catalyst rise are adapted such that yield of aromatics from C5 to C12 nonaromatic hydrocarbons is 5 to 60 wt.%, and regenerating the first catalyst and the second catalyst separately.
• Embodiment 12 is the method of embodiment 11, wherein the fractionating further produces a light recycling stream containing primarily C 4 to C6 hydrocarbons, a light olefin stream containing primarily C2 and C3 olefins, a dry gas stream containing primarily methane and hydrogen, collectively, an aromatic stream containing primarily benzene, toluene, and xylene, collectively.
• Embodiment 13 is the method of embodiment 12, wherein the light recycling stream is recycled back to the first catalyst riser.
• Embodiment 14 is the method of any of embodiments 11 to 13, wherein the first catalyst and/or the second catalyst contains an acidic porous zeolite including Mordenite Framework Inverted (MFI), Faujasite (FAET), Mordenite (MOR), Beta, Omega structure type zeolites.
• Embodiment 15 is the method of any of embodiments 11 to 14, wherein the first catalyst and the second catalyst are different in parameters including silicon to aluminum ratio, pore size, surface area, promoter composition, or combinations thereof.

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• 2019
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