CA1237692A - Dual riser fluid catalytic cracking process - Google Patents
Dual riser fluid catalytic cracking processInfo
- Publication number
- CA1237692A CA1237692A CA000467099A CA467099A CA1237692A CA 1237692 A CA1237692 A CA 1237692A CA 000467099 A CA000467099 A CA 000467099A CA 467099 A CA467099 A CA 467099A CA 1237692 A CA1237692 A CA 1237692A
- Authority
- CA
- Canada
- Prior art keywords
- catalyst
- feedstock
- riser
- contacting
- process according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 21
- 230000009977 dual effect Effects 0.000 title claims abstract description 8
- 238000004231 fluid catalytic cracking Methods 0.000 title claims abstract description 7
- 239000003054 catalyst Substances 0.000 claims abstract description 79
- 238000006243 chemical reaction Methods 0.000 claims abstract description 30
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000000571 coke Substances 0.000 claims abstract description 12
- 229910052751 metal Inorganic materials 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims abstract description 11
- 239000000356 contaminant Substances 0.000 claims abstract description 9
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 239000002243 precursor Substances 0.000 claims abstract description 5
- 238000000926 separation method Methods 0.000 claims description 21
- 229930195733 hydrocarbon Natural products 0.000 claims description 20
- 150000002430 hydrocarbons Chemical class 0.000 claims description 20
- 238000005336 cracking Methods 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- 239000000047 product Substances 0.000 claims description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- 238000009835 boiling Methods 0.000 claims description 8
- 239000007795 chemical reaction product Substances 0.000 claims description 8
- 239000004215 Carbon black (E152) Substances 0.000 claims description 7
- 239000002574 poison Substances 0.000 claims description 6
- 231100000614 poison Toxicity 0.000 claims description 6
- 239000012530 fluid Substances 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 claims description 3
- 239000003546 flue gas Substances 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 2
- 238000004523 catalytic cracking Methods 0.000 description 7
- 239000003502 gasoline Substances 0.000 description 4
- 230000008929 regeneration Effects 0.000 description 4
- 238000011069 regeneration method Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910017464 nitrogen compound Inorganic materials 0.000 description 3
- 150000002830 nitrogen compounds Chemical class 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 239000012084 conversion product Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 241001481828 Glyptocephalus cynoglossus Species 0.000 description 1
- NHTMVDHEPJAVLT-UHFFFAOYSA-N Isooctane Chemical compound CC(C)CC(C)(C)C NHTMVDHEPJAVLT-UHFFFAOYSA-N 0.000 description 1
- 235000014435 Mentha Nutrition 0.000 description 1
- 241001072983 Mentha Species 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- JVSWJIKNEAIKJW-UHFFFAOYSA-N dimethyl-hexane Natural products CCCCCC(C)C JVSWJIKNEAIKJW-UHFFFAOYSA-N 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000009963 fulling Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 235000014569 mints Nutrition 0.000 description 1
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
Landscapes
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
A B S T R A C T
DUAL RISER FLUID CATALYTIC CRACKING PROCESS
An improved fluid catalytic cracking process for achieving high conversions of low quality feedstocks (containing metal contaminants, basic nitrogen and/or coke precursors) at relatively low severities, by passing the feedstock in series through a dual riser reactor system having a common catalyst stripper and regenerator, in contact with freshly regenerated catalyst which is passed in parallel from the regenerator through each of the riser reactors.
DUAL RISER FLUID CATALYTIC CRACKING PROCESS
An improved fluid catalytic cracking process for achieving high conversions of low quality feedstocks (containing metal contaminants, basic nitrogen and/or coke precursors) at relatively low severities, by passing the feedstock in series through a dual riser reactor system having a common catalyst stripper and regenerator, in contact with freshly regenerated catalyst which is passed in parallel from the regenerator through each of the riser reactors.
Description
7~3~
DULL RISER Fluid CATALYTIC CRACKING PPDCESS
This invention relates to a dual riser fluid catalytic cracking pry ens wherein a low quality feed stock is passed through the risers in series; the fistic is in contact with freshly regenerated catalyst which is passed through the risers in parallel.
Catalytic cracking is the major molecular weigh reduction process employed in petroleum refix no for manufacturing gasoline as fuels. Business incentives require the processing of heavier, low-quality feed stocks, fewer output of residual products and increased energy efficiencies while meeting more stringent environmental constraints. Current catalysts require high temperature and short contact time riser reactors to obtain the full benefits of the process, i.e., highest selectivity to gasoline at highest conversion yields. These catalysts require high temperature regeneration Tao combustion). This approach also allows for catalysts with greater metals tolerance, octane enhancement and Six capture.
In the catalytic cracking of low quality hydrocarbon feed stocks, metal contaminants such as nickel, vanadium and iron are deposited on the catalyst and reduce its effectiveness in converting the feed stock to lower boiling components such as gasoline. One way of at least partially overcoming these adverse effects is by treating the catalyst with agents which reduce the anility of contaminants on the catalyst to adversely affect the Z5 cracking process. For example, in US. 4.326,990 selected treating agents are added to the feed stock; in the reactor these agents are deposited on the catalyst.
The effectiveness of a cracking catalyst is also reduced by temporary catalyst poisons such as basic nitrogen components and high boiling coke precursors, which reduce the ability of the catalyst to achieve high conversion of the feed without excessive cracking to undesirable light hydrocarbons.
In catalytic cracking many different reactor configurations have been proposed, all claiming to haze certain advantages. For example, in US. Patent 4,090,949 a aural riser reactor catalytic cracking system is disclosed, having a common catalyst regenerator supplying freshly regenerated catalyst to each riser, whilst fresh gas oil feed is contacted with freshly regenerated catalyst in the first riser and light C2-C5 olefins are contacted with freshly regenerated catalyst in the second riser. In another dual riser catalytic cracking system, as disclosed in US. Patent 3,748,251 charge stock is passed into a reaction zone together with a catalyst composition comprising two cracking components, part of which is ZSM-5, hydrocarbons are withdrawn from the reaction zone, unrequited hydrocarbon charge is separated and introduced into a second reaction zone together with said catalyst.
It is an object of this invention to remove from the feed stock essentially all of the temporary catalyst poisons, such as basic nitrogen constituents and coke precursors, an* metal contamiI~ults at relatively low conversions, e.g., 15 to 25~ in the first reactor, thereby requiring low severity, i.e., lower catalyst/oil ratios.
It is another object of the invention to catalytically crack the total product from the first reactor to a high conversion at low severity over freshly regenerated catalyst It is a further object of the invention that the total severity required for these two separate subsequent steps of cracking will be significantly lower than that required if the same total conversion were achieved in a single step.
It is a still further object of the invention to use a common catalyst inventory to remove metal contaminants comprising nickel and/or vanadium and temporary catalyst poisons and to achieve a high conversion of low quality feedstocksO
mix invention relates to an improved fluid catalytic cracking process for low quality hydrocarbon feed stocks, said ~23'7g~
process having a dual riser reactor system with a gammon catalyst stripper and regenerator, which comprises passing said feed stock into a first riser reactor zones an contacting said feed stock with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively low conversion of feed stocks to lower boiling components while simultaneously reducing metal con tam mints and temporary catalyst poisons contained therein; separating first riser reaction products from catalyst in a first separation zone and passing a 1.0 mixture of relatively clean unconverted feed stock and reaction products from said separation zone into a second riser reactor zone, and contacting the mixture with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively high conversion of feed stocks to lower boiling components; separating second riser reaction products from catalyst in a second separation zone; passing partially deactivated catalyst, containing metal contaminants, coke and unrequited hydrocarbons, from both separation zones to a catalyst stripper and contacting said catalyst with steam under conditions to remove a substantial portion of said unrequited and/or adsorbed hydrocarbons passing catalyst from the stripper to a regenerator and contacting said catalyst with air under reaction conditions suitable to ccmbust coke and unconverted hydrocarbons; separating combustion products from regenerated catalyst as flue gas; circulating freshly regenerated catalyst to both risers for contacting fresh feed stock and said mixture of unconverted feed stock and reaction products respectively; and recovering cracked products from the second separation zone.
The process according to the invention can be suitably applied to few quality hydrocarbon feed stocks containing metal contaminants comprising nickel and/or vanadium in amounts from about 1 to 100 parts per million by weight (ppmw). It can also be suitably applied to hydrocarbon feed stocks containing from about 300 to 8000 ppmw of basic nitrogen. Furthermore, the process can ,3 be suitably applied to hydrocarbon feed stocks containing from about 0.5 to 10 ow of coke precursors, determined as Rams bottom Carbon Residue. The process according to the invention is suitably carried out using well-kncwn catalysts, such as commercially available cracking catalysts and, in particular X or Y type zealots contained in a silica-alumina matrix.
The process according to the present invention, which is carried out in a two reactor-one regenerator system with the feed in series flow and the catalyst in parallel flow, is illustrated in Fig. 1.
In the dual riser catalytic cracking process shown in Fig. 1, the system includes primarily a catalyst regeneration zone 2, a catalyst stripper zone 4, a first catalyst separation zone 6, and a second catalyst separation zone 8.
Fresh feed stock is introduced into the system via line 10, where it is contacted with freshly regenerated catalyst from regenerator 2 via line 12. The feed stock and catalyst are passed under suitable reaction conditions upwardly through the first riser line 14) wherein the feed stock is partially converted to lower boiling components. The mixture of unconverted feed, conversion products and catalyst is then passed into a first separation zone 6, wherein catalyst and gaseous hydrocarbons are separated. An optional emkcdiment of the invention is to add prestripping steam to separation zone 6 via line 50. The separated catalyst, which is partially deactivated, is passed via line 16 to a riser pot 18, where it it contacted by steam introduced via line 30 an lifted via line 32 to catalyst stripper 4.
The gaseous hydrocarbons from separation zone 6 are passed via line 20 to the second riser (line 24) where they are contacted witch freshly regenerated catalyst from regenerator 2 via line 22 and passed under suitable reaction conditions upwardly through said second riser, wherein a substantial portion of the unconverted feed stock from catalyst separation zone 6 is converted to lower boiling components. me mixture of unconverted feed, 7~?2 conversion products and catalyst is then passed into a second separation zone 8, wherein catalyst and gaseous hydrocarbons are separated. An optional embodiment of the invention is to add prestripping steam to separation zone 8 via line 51. me separated catalyst, which is partially deactivated, is passed via line 26 to a riser pot 18, where it is combined with catalyst from separation zone 6, and is contacted by steam introduced via line 30 and lifted via line 32 to catalyst stripper 4.
The gaseous hydrocarbons from catalyst separation zone 8 are passed via line 40 to a fractionator where suitable cracked products are recovered.
The hydrocarbons and gases stripped from the catalyst in stripper 4 are passed via line 42 to the same or another fractionator for separation of water and recovery of products.
The stripped catalyst from stripper 4 is passed via line 28 to a regeneration zone 2, where it is contacted with air introduced via line 38. The partially deactived catalyst is regenerated under conditions suitable to remove coke and basic nitrogen compounds. Flue gases from the regeneration zone are vented via line 44. Freshly regenerated catalyst is circulated to the first and the second riser via lines 12 and 22, respectively, and the process is continued.
EXIT
-This example illustrates the benefits to be realized by removing temporary catalyst poisons from low quality catalytic cracking feed stocks.
TWO feedstccks, A (light flashed distillate) and B
(commercial FCCU feed), were deresined in the laboratory.
Properties of the total and deresined feed stocks are shown in Table lo Feed stock A was a fairly high quality, glean light flashed distillate and was included for comparison. Feed stock B
was a low quality feed, such as those suitable for the process of the invention, which contained a significant amount of basic nitrogen compounds.
37~
me deresining step consists of mixing the feed stocks with isooctane and passing -the mixture over attapulgas clay. Other suitable clays for this purpose include Elders Earth and Florex-S. m e twill resins, including the basic nitrogen compounds, are adsorbed on the clay.
Feed stocks A and B, both before and after deresining, were then tested in a micro activity test (MAT) unit.
The MAT used in these studies and the operating procedure were similar to those described in ASTM D 3907-80. Briefly about 5.0 grams of catalyst are contained in a small diameter reactor (ASTM specifies 15.6 em I.D.). The feed is passed over the catalyst for about 60 seconds. Immediately after the oil addition, nitrogen is introduced to strip the catalyst Both a liquid and a gas are recovered as products. These are conveniently analyzed by conventional chromatographic equipment.
The results of the micro activity tests are plotted in Figs.
AWOKE (feed stock A) and AWOKE (feed stock B). In all graphs, the straight lines relate to experiments carried out with total feed and the dotted lines relate to experiments carried out with deresined feed stock.
In Figures PA and PA the conversions of total feed and deresined feed stock, respectively into 232 C material, expressed as wow of 232 C material are plotted (on the horizontal axis) against the coke production in ow. In Figures 2B and 3B the conversions (as expressed for Figures PA and 3 A) are plotted against the yield of the C5-232 C fraction. Finally, in Figures 2C and 3C, respectively, the weight hourly space velocities are plotted (on the horizontal axis) against the conversions of total feed and deresined feed stock, respectively, as expressed herein before. It will be clear from the Figures AWOKE in comparison with Figures AWOKE that the imprsve~ent in cracking characteristics (less refractory, more gasoline and less coke) fulling deresining is significantly greater for Feed stock B than for Feed stock A.
* Trade Mark I
Cracking Feed stock B to a low conversion in a first riser reactor will achieve essentially the same benefits as the deresining treatment. The total product from us low conversion first reactor can then be easily cracked at GUY severity to a high conversion in a second riser reactor.
I
__ Feeds Feeds~cck A Feed stock B
-Total Deresined Total Deresined Feed if Feed Oil ) APT Gravity 24.7 25.6 22.7 24.7 Sol Weight 320 - 331 Basic No, OWE 0.00 0.10 0.00 Kowtows OW
Alikeness 22.4 23.4 10.1 11.2 Cycle Alikeness 34.6 36.2 40.1 Moo Aromatics 16.9 16.6 18.1 17.9 Do Aromatics 19.2 23.4 23.7 Try Aromatics 6.2 10.7 6.9 Tory Aromatics 0.1 OWE 0.5 0.2 Basic No Nuclei 0.2 0.0 1.0 COO
00.0 100.0 100.0 100. 0 I 4.3 ow Resins Removed
DULL RISER Fluid CATALYTIC CRACKING PPDCESS
This invention relates to a dual riser fluid catalytic cracking pry ens wherein a low quality feed stock is passed through the risers in series; the fistic is in contact with freshly regenerated catalyst which is passed through the risers in parallel.
Catalytic cracking is the major molecular weigh reduction process employed in petroleum refix no for manufacturing gasoline as fuels. Business incentives require the processing of heavier, low-quality feed stocks, fewer output of residual products and increased energy efficiencies while meeting more stringent environmental constraints. Current catalysts require high temperature and short contact time riser reactors to obtain the full benefits of the process, i.e., highest selectivity to gasoline at highest conversion yields. These catalysts require high temperature regeneration Tao combustion). This approach also allows for catalysts with greater metals tolerance, octane enhancement and Six capture.
In the catalytic cracking of low quality hydrocarbon feed stocks, metal contaminants such as nickel, vanadium and iron are deposited on the catalyst and reduce its effectiveness in converting the feed stock to lower boiling components such as gasoline. One way of at least partially overcoming these adverse effects is by treating the catalyst with agents which reduce the anility of contaminants on the catalyst to adversely affect the Z5 cracking process. For example, in US. 4.326,990 selected treating agents are added to the feed stock; in the reactor these agents are deposited on the catalyst.
The effectiveness of a cracking catalyst is also reduced by temporary catalyst poisons such as basic nitrogen components and high boiling coke precursors, which reduce the ability of the catalyst to achieve high conversion of the feed without excessive cracking to undesirable light hydrocarbons.
In catalytic cracking many different reactor configurations have been proposed, all claiming to haze certain advantages. For example, in US. Patent 4,090,949 a aural riser reactor catalytic cracking system is disclosed, having a common catalyst regenerator supplying freshly regenerated catalyst to each riser, whilst fresh gas oil feed is contacted with freshly regenerated catalyst in the first riser and light C2-C5 olefins are contacted with freshly regenerated catalyst in the second riser. In another dual riser catalytic cracking system, as disclosed in US. Patent 3,748,251 charge stock is passed into a reaction zone together with a catalyst composition comprising two cracking components, part of which is ZSM-5, hydrocarbons are withdrawn from the reaction zone, unrequited hydrocarbon charge is separated and introduced into a second reaction zone together with said catalyst.
It is an object of this invention to remove from the feed stock essentially all of the temporary catalyst poisons, such as basic nitrogen constituents and coke precursors, an* metal contamiI~ults at relatively low conversions, e.g., 15 to 25~ in the first reactor, thereby requiring low severity, i.e., lower catalyst/oil ratios.
It is another object of the invention to catalytically crack the total product from the first reactor to a high conversion at low severity over freshly regenerated catalyst It is a further object of the invention that the total severity required for these two separate subsequent steps of cracking will be significantly lower than that required if the same total conversion were achieved in a single step.
It is a still further object of the invention to use a common catalyst inventory to remove metal contaminants comprising nickel and/or vanadium and temporary catalyst poisons and to achieve a high conversion of low quality feedstocksO
mix invention relates to an improved fluid catalytic cracking process for low quality hydrocarbon feed stocks, said ~23'7g~
process having a dual riser reactor system with a gammon catalyst stripper and regenerator, which comprises passing said feed stock into a first riser reactor zones an contacting said feed stock with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively low conversion of feed stocks to lower boiling components while simultaneously reducing metal con tam mints and temporary catalyst poisons contained therein; separating first riser reaction products from catalyst in a first separation zone and passing a 1.0 mixture of relatively clean unconverted feed stock and reaction products from said separation zone into a second riser reactor zone, and contacting the mixture with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively high conversion of feed stocks to lower boiling components; separating second riser reaction products from catalyst in a second separation zone; passing partially deactivated catalyst, containing metal contaminants, coke and unrequited hydrocarbons, from both separation zones to a catalyst stripper and contacting said catalyst with steam under conditions to remove a substantial portion of said unrequited and/or adsorbed hydrocarbons passing catalyst from the stripper to a regenerator and contacting said catalyst with air under reaction conditions suitable to ccmbust coke and unconverted hydrocarbons; separating combustion products from regenerated catalyst as flue gas; circulating freshly regenerated catalyst to both risers for contacting fresh feed stock and said mixture of unconverted feed stock and reaction products respectively; and recovering cracked products from the second separation zone.
The process according to the invention can be suitably applied to few quality hydrocarbon feed stocks containing metal contaminants comprising nickel and/or vanadium in amounts from about 1 to 100 parts per million by weight (ppmw). It can also be suitably applied to hydrocarbon feed stocks containing from about 300 to 8000 ppmw of basic nitrogen. Furthermore, the process can ,3 be suitably applied to hydrocarbon feed stocks containing from about 0.5 to 10 ow of coke precursors, determined as Rams bottom Carbon Residue. The process according to the invention is suitably carried out using well-kncwn catalysts, such as commercially available cracking catalysts and, in particular X or Y type zealots contained in a silica-alumina matrix.
The process according to the present invention, which is carried out in a two reactor-one regenerator system with the feed in series flow and the catalyst in parallel flow, is illustrated in Fig. 1.
In the dual riser catalytic cracking process shown in Fig. 1, the system includes primarily a catalyst regeneration zone 2, a catalyst stripper zone 4, a first catalyst separation zone 6, and a second catalyst separation zone 8.
Fresh feed stock is introduced into the system via line 10, where it is contacted with freshly regenerated catalyst from regenerator 2 via line 12. The feed stock and catalyst are passed under suitable reaction conditions upwardly through the first riser line 14) wherein the feed stock is partially converted to lower boiling components. The mixture of unconverted feed, conversion products and catalyst is then passed into a first separation zone 6, wherein catalyst and gaseous hydrocarbons are separated. An optional emkcdiment of the invention is to add prestripping steam to separation zone 6 via line 50. The separated catalyst, which is partially deactivated, is passed via line 16 to a riser pot 18, where it it contacted by steam introduced via line 30 an lifted via line 32 to catalyst stripper 4.
The gaseous hydrocarbons from separation zone 6 are passed via line 20 to the second riser (line 24) where they are contacted witch freshly regenerated catalyst from regenerator 2 via line 22 and passed under suitable reaction conditions upwardly through said second riser, wherein a substantial portion of the unconverted feed stock from catalyst separation zone 6 is converted to lower boiling components. me mixture of unconverted feed, 7~?2 conversion products and catalyst is then passed into a second separation zone 8, wherein catalyst and gaseous hydrocarbons are separated. An optional embodiment of the invention is to add prestripping steam to separation zone 8 via line 51. me separated catalyst, which is partially deactivated, is passed via line 26 to a riser pot 18, where it is combined with catalyst from separation zone 6, and is contacted by steam introduced via line 30 and lifted via line 32 to catalyst stripper 4.
The gaseous hydrocarbons from catalyst separation zone 8 are passed via line 40 to a fractionator where suitable cracked products are recovered.
The hydrocarbons and gases stripped from the catalyst in stripper 4 are passed via line 42 to the same or another fractionator for separation of water and recovery of products.
The stripped catalyst from stripper 4 is passed via line 28 to a regeneration zone 2, where it is contacted with air introduced via line 38. The partially deactived catalyst is regenerated under conditions suitable to remove coke and basic nitrogen compounds. Flue gases from the regeneration zone are vented via line 44. Freshly regenerated catalyst is circulated to the first and the second riser via lines 12 and 22, respectively, and the process is continued.
EXIT
-This example illustrates the benefits to be realized by removing temporary catalyst poisons from low quality catalytic cracking feed stocks.
TWO feedstccks, A (light flashed distillate) and B
(commercial FCCU feed), were deresined in the laboratory.
Properties of the total and deresined feed stocks are shown in Table lo Feed stock A was a fairly high quality, glean light flashed distillate and was included for comparison. Feed stock B
was a low quality feed, such as those suitable for the process of the invention, which contained a significant amount of basic nitrogen compounds.
37~
me deresining step consists of mixing the feed stocks with isooctane and passing -the mixture over attapulgas clay. Other suitable clays for this purpose include Elders Earth and Florex-S. m e twill resins, including the basic nitrogen compounds, are adsorbed on the clay.
Feed stocks A and B, both before and after deresining, were then tested in a micro activity test (MAT) unit.
The MAT used in these studies and the operating procedure were similar to those described in ASTM D 3907-80. Briefly about 5.0 grams of catalyst are contained in a small diameter reactor (ASTM specifies 15.6 em I.D.). The feed is passed over the catalyst for about 60 seconds. Immediately after the oil addition, nitrogen is introduced to strip the catalyst Both a liquid and a gas are recovered as products. These are conveniently analyzed by conventional chromatographic equipment.
The results of the micro activity tests are plotted in Figs.
AWOKE (feed stock A) and AWOKE (feed stock B). In all graphs, the straight lines relate to experiments carried out with total feed and the dotted lines relate to experiments carried out with deresined feed stock.
In Figures PA and PA the conversions of total feed and deresined feed stock, respectively into 232 C material, expressed as wow of 232 C material are plotted (on the horizontal axis) against the coke production in ow. In Figures 2B and 3B the conversions (as expressed for Figures PA and 3 A) are plotted against the yield of the C5-232 C fraction. Finally, in Figures 2C and 3C, respectively, the weight hourly space velocities are plotted (on the horizontal axis) against the conversions of total feed and deresined feed stock, respectively, as expressed herein before. It will be clear from the Figures AWOKE in comparison with Figures AWOKE that the imprsve~ent in cracking characteristics (less refractory, more gasoline and less coke) fulling deresining is significantly greater for Feed stock B than for Feed stock A.
* Trade Mark I
Cracking Feed stock B to a low conversion in a first riser reactor will achieve essentially the same benefits as the deresining treatment. The total product from us low conversion first reactor can then be easily cracked at GUY severity to a high conversion in a second riser reactor.
I
__ Feeds Feeds~cck A Feed stock B
-Total Deresined Total Deresined Feed if Feed Oil ) APT Gravity 24.7 25.6 22.7 24.7 Sol Weight 320 - 331 Basic No, OWE 0.00 0.10 0.00 Kowtows OW
Alikeness 22.4 23.4 10.1 11.2 Cycle Alikeness 34.6 36.2 40.1 Moo Aromatics 16.9 16.6 18.1 17.9 Do Aromatics 19.2 23.4 23.7 Try Aromatics 6.2 10.7 6.9 Tory Aromatics 0.1 OWE 0.5 0.2 Basic No Nuclei 0.2 0.0 1.0 COO
00.0 100.0 100.0 100. 0 I 4.3 ow Resins Removed
(2) 9.8 ow Resins Removed
Claims (6)
1. An improved fluid catalytic cracking process for low quality hydrocarbon feedstocks, said process having a dual riser reactor system with a common catalyst stripper and regenerator, which comprises passing said feedstock into a first riser reactor zone and contacting said feedstock with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively low conversion of feedstocks to lower boiling components while simultaneously reducing metal contaminants and temporary catalyst poisons contained therein;
separating first riser reaction products from catalyst in a first separation zone and passing a mixture of relatively clean un-converted feedstock and reaction products from said separation zone into a second riser reactor zone and contacting the mixture with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively high conversion of feedstocks to lower boiling components; separating second riser reaction products from catalyst in a second separation zone; passing partially deactivated catalyst, containing metal contaminants, coke and unreacted hydrocarbons from both separation zones to a catalyst stripper and contacting said catalyst with stem under conditions to remove a substantial portion of said unreacted and/or adsorbed hydrocarbons; passing catalyst from the stripper to a regenerator and contacting said catalyst with air under reaction conditions suitable to combust coke and unconverted hydrocarbons; separating combustion products from regenerated catalyst as flue gas; circulating freshly regenerated catalyst to both risers for contacting fresh feedstock and said mixture of unconverted feedstock and reaction products, respectively; and recovering cracked products from the second separation zone.
separating first riser reaction products from catalyst in a first separation zone and passing a mixture of relatively clean un-converted feedstock and reaction products from said separation zone into a second riser reactor zone and contacting the mixture with freshly regenerated fluid cracking catalyst under relatively low severity reaction conditions suitable for relatively high conversion of feedstocks to lower boiling components; separating second riser reaction products from catalyst in a second separation zone; passing partially deactivated catalyst, containing metal contaminants, coke and unreacted hydrocarbons from both separation zones to a catalyst stripper and contacting said catalyst with stem under conditions to remove a substantial portion of said unreacted and/or adsorbed hydrocarbons; passing catalyst from the stripper to a regenerator and contacting said catalyst with air under reaction conditions suitable to combust coke and unconverted hydrocarbons; separating combustion products from regenerated catalyst as flue gas; circulating freshly regenerated catalyst to both risers for contacting fresh feedstock and said mixture of unconverted feedstock and reaction products, respectively; and recovering cracked products from the second separation zone.
2. A process according to claim 1, wherein the feedstock contains from about 1 to 100 ppmw of metal contaminants comprising nickel and/or vanadium.
3. A process according to claim 1, wherein the feedstock contains from about 300 to 8000 ppmw of basic nitrogen.
4. A process according to claim 1, wherein the feedstock contains from about 0.5 to 10 %w of coke precursors determined as Ramsbottom Carbon Residue.
5. A process according to claim 1, wherein the conversion in the first riser is in the range of about 15 to 25 %w based on the feedstock.
6. A process according to claim 1, wherein the conversion after the second riser is between about 55 and 80 %w, based on the fresh feedstock.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US55446983A | 1983-11-22 | 1983-11-22 | |
| US554,469 | 1983-11-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1237692A true CA1237692A (en) | 1988-06-07 |
Family
ID=24213454
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000467099A Expired CA1237692A (en) | 1983-11-22 | 1984-11-06 | Dual riser fluid catalytic cracking process |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0142900B1 (en) |
| JP (1) | JPS60144388A (en) |
| CA (1) | CA1237692A (en) |
| DE (1) | DE3479427D1 (en) |
| NL (1) | NL8403539A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU4777000A (en) * | 2000-02-16 | 2001-08-27 | Indian Oil Corporation Limited | A multi stage selective catalytic cracking process and a system for producing high yield of middle distillate products from heavy hydrocarbon feedstocks |
| US20080011644A1 (en) | 2006-07-13 | 2008-01-17 | Dean Christopher F | Ancillary cracking of heavy oils in conjuction with FCC unit operations |
| US8124020B2 (en) | 2009-03-04 | 2012-02-28 | Uop Llc | Apparatus for preventing metal catalyzed coking |
| US8124822B2 (en) | 2009-03-04 | 2012-02-28 | Uop Llc | Process for preventing metal catalyzed coking |
| KR101954472B1 (en) | 2011-07-27 | 2019-03-05 | 사우디 아라비안 오일 컴퍼니 | Fluidized catalytic cracking of paraffinic naphtha in a downflow reactor |
| EP3106504B1 (en) | 2015-06-19 | 2020-02-05 | Reliance Industries Limited | Process for propylene and lpg recovery in fcc fuel gas |
| US9896627B2 (en) | 2015-10-14 | 2018-02-20 | Saudi Arabian Oil Company | Processes and systems for fluidized catalytic cracking |
| US20230407187A1 (en) * | 2022-06-17 | 2023-12-21 | Kellogg Brown & Root Llc | Converting Motor Fuels Range Distillates to Light Olefins in a Multiple Riser Fluid Catalytic Cracking (FCC) Unit |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3751359A (en) * | 1971-09-27 | 1973-08-07 | Texaco Inc | Conversion of hydrocarbons |
| US3894933A (en) * | 1974-04-02 | 1975-07-15 | Mobil Oil Corp | Method for producing light fuel oil |
| US4090949A (en) * | 1974-07-31 | 1978-05-23 | Mobil Oil Corportion | Upgrading of olefinic gasoline with hydrogen contributors |
| US4073717A (en) * | 1976-01-26 | 1978-02-14 | Aliev Vagab Safarovich | Process for producing gasoline |
| FR2378847A1 (en) * | 1977-01-28 | 1978-08-25 | Melik Akhnazarov Talyat | Two=stage catalytic hydrocarbon cracking - with co-current and counter current reaction stages |
| US4728416A (en) * | 1979-11-14 | 1988-03-01 | Ashland Oil, Inc. | Cracking blends of gas oil and residual oil |
-
1984
- 1984-11-06 CA CA000467099A patent/CA1237692A/en not_active Expired
- 1984-11-16 DE DE8484201664T patent/DE3479427D1/en not_active Expired
- 1984-11-16 EP EP19840201664 patent/EP0142900B1/en not_active Expired
- 1984-11-20 JP JP24356084A patent/JPS60144388A/en active Pending
- 1984-11-21 NL NL8403539A patent/NL8403539A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0142900A2 (en) | 1985-05-29 |
| EP0142900A3 (en) | 1986-01-22 |
| JPS60144388A (en) | 1985-07-30 |
| NL8403539A (en) | 1985-06-17 |
| DE3479427D1 (en) | 1989-09-21 |
| EP0142900B1 (en) | 1989-08-16 |
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