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
  • C10G51/06—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more cracking processes only plural parallel stages only
• • 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

Definitions

• the present invention relates to a process and a catalytic cracking device (FCC) in entrained bed comprising reactors in parallel comprising at least one downflow reactor (dropper) and at least one upward catalyst reactor (commonly called riser) from at least one regeneration zone.
• FCC catalytic cracking device
• catalytic cracking units comprising a double regeneration with injection of the charge in the form of fine droplets met the need to work on heavy cuts.
• Patent application FT98 / 14319 describes a chain of a dropper and a riser in series. It describes in detail the advantages of a second reactor which is operated under very different conditions in temperature and C / O of the main riser: in particular, this second reactor advantageously represents an additional capacity for treating a heavy load in producing a minimal amount of coke compared to a conventional reactor; it also becomes possible to crack certain cuts (called recycles) from the main riser that are not desirable (low recovery or cuts that do not meet certain specifications such as sulfur or aromatic contents) in order to maximize the yield of recovered cuts (LPG, petrol) .
• recycles certain cuts
• the fresh charge is introduced at the bottom of the riser and it is the LCO produced from the riser which is introduced as the charge for the dropper.
• the LCO produced from the riser which is introduced as the charge for the dropper.
• Such a configuration makes it possible to maximize the gasoline yield by exhausting the LCO under relatively severe cracking conditions.
• the drawback of this system with a dropper and a riser in series is that for a large load capacity at the dropper, the ascending reactor works with a non-negligible amount of catalyst partially deactivated by its passage through the dropper (deactivation coming from the deposit of coke on the catalyst). This results in a reduced efficiency which does not allow to draw the full potential of this association.
• US Patent 4116814 also illustrates the case of two reactors with upward flow in parallel, connected to a particle regenerator.
• An object of the invention is to remedy the drawbacks of the prior art.
• Another object is to crack both heavy and light hydrocarbons under reaction conditions which are severe, in a reactor adapted to this type of conditions, the dropper or downflow reactor and much less severe in a riser or reactor. upward flow so as to favor the formation of very different products meeting the specificities of each type of reactor.
• the invention relates to a process for catalytic cracking in a entrained or fluidized bed of at least one charge of hydrocarbons in at least two reaction zones, at least one of which is of upward flow, into which the charge is introduced and catalyst from at least one regeneration zone in the lower part of the upward flow reaction zone, the charge and the catalyst are circulated from bottom to top in said zone, the first gases produced from the coke catalyst are separated in a first separation zone, the catalyst is stripped by means of a stripping gas, a first cracking and stripping effluent is recovered and the coke catalyst is recycled in the regeneration zone and it is at least partly regenerated by means of '' an oxygen-containing gas, the process being characterized in that catalyst is introduced from at least one regeneration zone and a hydrocarbon charge e in the upper part of at least one reaction zone with downward flow, the catalyst and said charge are circulated there from top to bottom under appropriate conditions, the coke catalyst is separated from the second gases produced in a second separation zone, the second gases produced are recovered and the coke catalyst
• the temperature of the catalyst leaving the descending reactor can be higher than that leaving the ascending reactor.
• the catalyst originating from the second separation zone can be stripped by means of a recycling gas which is usually steam and the resulting hydrocarbons are generally recovered with the cracking gases. It is preferable to regenerate the coke catalyst in two consecutive regeneration zones, each of which has its own combustion gas discharge resulting from the regeneration of the coke catalyst.
• the catalyst to be regenerated from the first separation zone is introduced into a first regeneration zone operating at an appropriate temperature, the catalyst thus at least partially regenerated being sent to the second regeneration zone operating at a higher temperature and the catalyst regenerated from the second regeneration zone is introduced into the upward flow reaction zone and into the downflow reaction zone.
• the coke catalyst from the second separation zone can be recycled in the first regeneration zone either by gravity flow, generally in the dense zone, or by flow by means of a riser comprising fluidizing air as engine ( lift), usually in the diluted area of the first regeneration area.
• the hydrocarbon feedstock or each of the feedstocks, if they are different, can be introduced into the upward reaction zone and into the downward reaction zone by a co-current injection of the catalyst flow or against the current, or against the current. current for one and co-current for the other. However, an injection against the current in the two zones seems preferable for better vaporization of the droplets introduced.
• the operating conditions for catalytic cracking of the charges are usually as follows:
• catalyst temperature (RD outlet) 500-650 ° C, preferably 560-620 ° C;
• the charge supplying each of the reaction zones can be a so-called fresh charge, a recycle of part of the products from a downstream fractionation or a mixture of of them.
• the charge of one of the reaction zones can be either heavier or lighter than that circulating in the other zone. More particularly, the charge of the upward flow reaction zone can be a vacuum distillate or an atmospheric residue or a recycle of part of the products from the downward reaction zone and the charge of the downflow zone is a non-charge. cracked or recycled part of the products from the bottom-up reaction zone and preferably a petrol cut or an LCO cut.
• the feed rate and for example of recycle flow (LCO cut, HCO or gasoline) circulating in the descending reactor can represent less than 50% by weight of the feed rate to be converted in the upward reaction zone.
• the dropper loop can be adapted to most existing cracking units, to one or two regenerators and / or with a technology of separation, stripping and transfer of the catalyst best suited to the requirements of the client.
• the coke content is therefore reduced very significantly so that the amount of heat given off by the combustion of this additional coke in the regenerator (s) is much less than the quantity of heat consumed by the vaporization of the feedstock and the heat of reaction in the dropper reactor.
• the catalyst on the regeneration side is cooled compared to the previous situation comprising only one traditional riser.
• This heat extraction effect which can be obtained in an equivalent manner by a regeneration side heat exchanger (catcooler) or by the vaporization of an almost chemically inert recycle (TCM) downstream of the charge injection into the direction of flow of the catalyst in a riser or dropper reactor, makes it possible either to treat charges with a higher carbon Conradson, or to increase the charge rate, or to take advantage of the decrease in temperature at the regenerator (s) ) to increase the circulation of catalyst (C / O) at the riser and the dropper.
• the heat necessary for the reaction and for vaporization on the reaction side is supplied by the regenerated catalyst, heated by combustion of the coke to the regenerator (s).
• the heat extraction effect requires increasing the circulation of catalyst at a constant charge rate and therefore benefiting from better catalytic activity (more active sites). We can also treat more refractory charges in the dropper.
• the invention also relates to a catalytic cracking device in a entrained or fluidized bed of a hydrocarbon feedstock comprising: - At least one substantially vertical ascending reactor having a lower inlet and an upper outlet:
• a first means for supplying regenerated catalyst connected to at least one coke catalyst regenerator and connected to said lower inlet; - a first means for supplying the load disposed above the lower inlet of the ascending reactor;
• the device being characterized in that it comprises at least one substantially vertical descending reactor having an upper inlet and a lower outlet;
• a second means for supplying regenerated catalyst connected to said coke catalyst regenerator and connected to said upper inlet of the descending reactor; a second means for supplying the load disposed below the second supply means;
• a second enclosure for separation of the coke catalyst from a second gas phase connected to the lower outlet of the descending reactor and having an outlet from the second gas phase and an outlet from the coke catalyst, and second means for recycling the coke catalyst connected to said catalyst outlet from the second separation enclosure and connected to the regenerator.
• the second enclosure for separating the catalyst from the cracking effluents may not include a stripping chamber.
• prestripage means for example by water vapor can be introduced into the separation enclosure and the evacuation of the vapor can be carried out with the cracking and prestripage effluents.
• the second separation enclosure comprises a catalyst stripping chamber with injection of stripping vapor, in communication with it, like that described for example in the patent application of the Applicant FR 98 / 09.672 incorporated as reference. Cracking and stripping effluents are generally removed by common means.
• the device can comprise two superposed regenerators of coke catalyst, the second being located above the first, means for circulating the catalyst from the first regenerator to the second regenerator.
• the said first and second catalyst supply means are connected to the second regenerator and the lower outlet of the first separation enclosure is connected to the first regenerator via the first recycling means.
• a regeneration zone (1) of the coke catalyst comprises two regeneration chambers (2) and (3) superimposed in which the catalyst is regenerated in a fluidized bed, air being introduced at the base of each chamber by means not shown in the figure.
• Each enclosure has its own dedusting means (4, 5) (cyclones) and evacuation (9, 10) of the coke combustion effluents.
• each enclosure (2) and (3) can be controlled by valves located on the lines allowing the evacuation of the combustion effluents at least partially dusted.
• the catalyst is transported between the two enclosures by means of a lift column (6).
• Air generally introduced at the base by an injector (7), at a sufficient speed makes it possible to transport the catalyst between the two enclosures.
• the proportion of air required for regeneration is 30 to 70% in the lower enclosure (2) operating at a lower temperature (670 ° C for example) and 15 to 40% in the upper enclosure (3 ) operating at a higher temperature (770 ° C for example), 5 to 20% of air circulating in the lift to transport the catalyst.
• a valve on solid (8), of the plug valve type makes it possible to control the flow of circulation between the chambers (2) and (3).
• the substantially regenerated catalyst from the second regenerator located above the first (3) is sent from a dense bed (11) into a disengagement well (13) by a conduit (12) inclined at an angle usually between 30 and 70 degrees from the horizontal.
• the circulation of the catalyst is slowed down to allow any gas bubbles to be evacuated towards the second regeneration enclosure (3) through a pressure equalization line (14).
• the catalyst is then accelerated and descends through a transfer tube (15) to the entry of a downflow reactor (16).
• the catalyst is kept in the fluidized state by the addition of small quantities of gas throughout the transport. If the catalyst is thus maintained in the fluidized state, this makes it possible to obtain a pressure at the inlet of the dropper greater than that of the fumes from the external cyclones (5).
• the dropper (16) comprises means for introducing the regenerated catalyst (17) which can be a valve on solid, an orifice or simply the opening of a conduit, in a contacting zone (18) located under the valve (17), where the catalyst meets countercurrent for example, the hydrocarbon charge, introduced by injectors (19), generally consisting of atomizers where the charge is finely divided into droplets thanks to the introduction of auxiliary fluids such as water vapor.
• injectors (19) generally consisting of atomizers where the charge is finely divided into droplets thanks to the introduction of auxiliary fluids such as water vapor.
• the means for introducing the catalyst are located above the means for introducing the charge.
• a reaction zone (21) of substantially elongated shape, shown vertically in the figure but this condition is not exclusive.
• the average residence time of the hydrocarbons in zones (18) and (21) will, for example, be less than 650 ms, preferably between 50 and 500 ms.
• the dropper effluents are then separated in the separator (20), for example as described in application FR98 / 09672 incorporated as a reference where the residence time must be limited as much as possible.
• the gaseous effluents (cracked gases) from the separator can then undergo an additional dusting step through cyclones, for example external cyclones (22) arranged downstream on a line (23). These gaseous effluents (cracked gases) are discharged through a line (24).
• the catalyst in the fluidized bed (28) then undergoes stripping (contact with a light gas such as water vapor, nitrogen, ammonia, hydrogen or even hydrocarbons, the number of carbon atoms is less than 3) by means which are well described in the prior art before being transferred to the riser (25) through the conduit (26).
• the stripping gas effluents are generally evacuated from the fluidized bed (28) through the same means (23, 22) which allow the evacuation of the gaseous effluents from the dropper (16) by the line (24).
• the coke catalyst is raised by a fluidizing gas (29) in the dense fluidized bed of the second regenerator (3).
• the riser reaction zone (30) is a substantially elongated tubular zone, many examples of which are described in the prior art.
• the hydrocarbon charge is introduced by means (31), generally consisting of atomizers where the charge is finely divided into droplets, generally using the introduction of auxiliary fluids such as water vapor, introduced through the means (31).
• the means for introducing the catalyst are located below the means for introducing the charge.
• the feed introduction is located above the catalyst inlet.
• These means for introducing the catalyst into the riser (30) comprise a withdrawal well (32) conforming to that (13) which supplies the dropper, connected to the dense bed of the second catalyst regenerator (3) by a conduit (33). inclined at substantially the same angle as that of the conduit (12).
• the well (32) is furthermore connected to the diluted fluidized bed by a pressure equalization line (34).
• a line (35) At the base of the well, a line (35) first vertical then inclined is connected to the lower part of the riser.
• a control valve (36) arranged on the line (35) regulates the flow rate of regenerated catalyst at the inlet of the riser as a function of the catalyst outlet temperature and of the effluents at the top of the riser.
• Fluidizing gas introduced at the base of the riser by injection means (37) circulates the catalyst cocurrently with the charge in the riser.
• the charge could have been injected against the current of the downward flow of the riser.
• an injection of a light cut of hydrocarbons or a heavier cut (LCO or HCO for example), coming from a distillation downstream of the riser cracking effluents, can be carried out in this riser.
• the cut introduced can represent 10 to 50% by weight of the load introduced into the riser and can contribute to maximizing the production of gasoline.
• the cracking reaction takes place in the riser.
• the cracked effluents are then separated in a separator (38), for example as described in PCT application FR 98/01866 incorporated as a reference.
• the catalyst resulting from the separation is then introduced into a fluidized bed (39) of a stripping chamber (40) located below the separator, through conduits (41) or openings.
• the catalyst in the chamber (39, 40) is then stripped (contact with a light gas such as water vapor, nitrogen, ammonia, hydrogen or even hydrocarbons with a number of carbon atoms less than 3) by means not shown in the figure.
• the stripped catalyst is then transferred to the dense bed of the first regeneration enclosure (2) by a conduit (45).
• the gaseous effluents from cracking and stripping separated in the separator (38) are discharged through a conduit (42) to a secondary separator (43) such as a cyclone, for example internal to the chamber (39, 40) before be directed to the downstream fractionation section by a conduit (44).
• a secondary separator (43) such as a cyclone, for example internal to the chamber (39, 40) before be directed to the downstream fractionation section by a conduit (44).
• the results of this comparison are based on industrial results obtained with the unit with the riser and pilot tests of 'cracking the reporting cut.
• the new conditions enabling the thermal balance of the unit as a whole to be satisfied are recalculated with a process model.
• the fresh charge (vacuum distillate) has the following characteristics: - Density d 15 : 0.937 - Sulfur content: 0.5%
• This catalyst based on Y zeolite has the following characteristics:
• the catalyst comes from the second regenerator.
• the cracked effluents are distilled and part of the HCO cut obtained as well as all of a heavy gasoline cut (170 ° C-200 ° C) are recycled into the riser.
• This recycle consisting of 49.3% HCO and 50.7% of heavy petrol cut, represents 27.1% by weight of the fresh charge at the riser.
• An additional cut is recycled as feed to the dropper which is in turn fed with catalyst from the second regenerator.
• the coke catalyst from the stripper connected to the riser is recycled in the dense phase of the first regenerator while that from the stripper connected to the dropper is recycled by means of a lift in the dense phase of the second regenerator.
• the conditions are maintained at the riser (ROT and recycles) by increasing the C / O of the riser.
• RD descending reactor (residence time: 0.4 s)
• REG1 first regeneration enclosure
• REG2 second regeneration chamber
• propylene can be produced in substantial quantity (53% more) by a really severe cracking with a dropper, while maintaining a satisfactory fuel yield.
• the temperature of the second regenerator dropped by 21 ° C (catcooler effect).
• a gain in conversion of the fresh charge of 1.9% is obtained by exhausting the LCO and slurry.
• the conditions are maintained at the riser (ROT and recycles) by increasing the C / O of the riser.
• the HCO slurry
• the temperature of the second regenerator dropped by 11 ° C (catcooler effect)
• a gain in conversion of the fresh charge of 4.8% is obtained by exhausting the slurry, leading to better yields of recoverable products (more than 1.5% of LPG and 2.3% more petrol)

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• 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)
• Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
• Processing Of Solid Wastes (AREA)

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• 1999
  • 1999-12-14 FR FR9915747A patent/FR2802211B1/fr not_active Expired - Lifetime
• 2000
  • 2000-11-28 US US10/149,597 patent/US7220351B1/en not_active Expired - Lifetime
  • 2000-11-28 WO PCT/FR2000/003315 patent/WO2001044409A1/fr not_active Application Discontinuation
  • 2000-11-28 ES ES00983393T patent/ES2359623T3/es not_active Expired - Lifetime
  • 2000-11-28 DE DE60045600T patent/DE60045600D1/de not_active Expired - Lifetime
  • 2000-11-28 EP EP00983393A patent/EP1242569B1/de not_active Expired - Lifetime
  • 2000-11-28 JP JP2001545489A patent/JP4671089B2/ja not_active Expired - Lifetime
  • 2000-11-28 AT AT00983393T patent/ATE497527T1/de active
• 2002
  • 2002-06-11 MX MXPA02005794A patent/MXPA02005794A/es active IP Right Grant
  • 2002-06-13 ZA ZA200204751A patent/ZA200204751B/en unknown

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