EP1131389B1 - Method and device for catalytic cracking comprising reactors with descending and ascending flows - Google Patents

Method and device for catalytic cracking comprising reactors with descending and ascending flows Download PDF

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Publication number
EP1131389B1
EP1131389B1 EP99972244A EP99972244A EP1131389B1 EP 1131389 B1 EP1131389 B1 EP 1131389B1 EP 99972244 A EP99972244 A EP 99972244A EP 99972244 A EP99972244 A EP 99972244A EP 1131389 B1 EP1131389 B1 EP 1131389B1
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Prior art keywords
catalyst
reactor
zone
feed
riser
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German (de)
French (fr)
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EP1131389A1 (en
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Thierry Gauthier
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IFP Energies Nouvelles IFPEN
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IFP Energies Nouvelles IFPEN
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    • 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 method and a device for the catalytic cracking of hydrocarbon charges.
  • the cracking reaction takes place in an elongated enclosure of substantially circular cross section, the catalyst being admitted to the lower part of the enclosure and the hydrocarbon feed previously atomized.
  • the contacting of the feedstock with the hot catalyst makes it possible to vaporize the hydrocarbons which then drive the catalyst towards the upper part of the reaction zone, the introduction of a driving fluid aiding the upward movement.
  • the products formed during the reaction have a very wide range of boiling points.
  • the products formed are generally distinguished according to their boiling point and their chemical nature: dry gases H2, H2S, molecules having 1 or 2 carbon atoms LPG (liquefied petroleum gases) molecules with 3 or 4 carbon atoms gasoline Molecules having at least 5 carbon atoms and boiling in less than 220 ° C LCO (light cycle oil) molecules whose boiling point is greater than 220 ° C and less than 360 ° C slurry molecules boiling in excess of 360 ° C coke heavy molecules (generally polyaromatic remaining adsorbed on the catalyst after the reaction).
  • dry gases H2, H2S molecules having 1 or 2 carbon atoms
  • LPG liquefied petroleum gases
  • gasoline Molecules having at least 5 carbon atoms and boiling in less than 220 ° C LCO (light cycle oil) molecules whose boiling point is greater than 220 ° C and less than 360 ° C slurry molecules boiling in excess of 360 ° C coke heavy molecules (generally polyaromatic remaining adsorbed on the catalyst after the reaction).
  • the yields that are generally obtained naturally depend on the quality of the treated feeds.
  • the observed yields (in% weight of the load) on the units are: dry gas 1-5% LPG 10-25% gasoline 30-55% OCH 15-25% slurry 5-20% coke 3-10%
  • the formed coke is burned in one or more chambers called regenerators to which the catalyst flows at its outlet from the reactor.
  • the heat produced by the combustion of the coke makes it possible to heat the catalyst, which is then reintroduced at the reactor inlet and brought into contact with the feedstock.
  • the catalytic cracking process is an adiabatic process.
  • the heat recovered by the catalyst during its passage through the regeneration zone is equal to the heat lost by the catalyst as it passes through the reaction zone. This therefore imposes on the operator operating conditions that are not independent of each other.
  • the operating conditions that affect the most efficiencies and selectivities for a given reactor are essentially the catalyst flow, which is generally related to the feed rate under the name C / O (C for Catalyst and O for Oil).
  • OLC which may be of interest in countries where middle distillates are in high demand in the fuel market, but LPGs (including propylene) and gasoline are unlikely to be maximized.
  • reaction zones generally used in the majority of cracking units current catalytic converters make it easy to operate under conditions of little cracking severe (C / O from 4 to 8 and reactor outlet temperatures of 500 to 550 ° C).
  • Time to hydrocarbon residence in this reaction zone consisting at least of a tube of substantially circular and elongated section in which the fluids flow globally from bottom to top commonly called riser, and from a separation system cracking vapors and catalyst is generally greater than 2s, of the order of 2 to About 10s.
  • the residence time of the hydrocarbons in contact with the catalyst is often itself greater than 1 s.
  • the downstream reactor combined with a mixture, as described in patent WO / FR98 / 12279, makes it possible to optimize the selectivities in recoverable products (LPG, gasolines) by minimizing the products not recoverable (a small increase in coke compared to a conventional reactor, but in very different temperature and C / O conditions, about 30% less gas dry compared to conventional technology) and to maximize conversion, thanks to obtaining conditions of very serious severity.
  • the main advantage of this type of device is to be able to contact catalyst and load optimally through the initial use of a downflow reactor.
  • the amount of coke present on the catalyst varies between 0.7 and 1.5% by weight, depending on the feedstock treated, the catalyst, operating conditions and the dimensioning of the unit. We know that under these conditions, the residual activity of the catalyst is low. It is therefore illusory to want to reintroduce catalyst in a new reaction chamber.
  • the catalyst from the downstream reactor can advantageously be introduced again into a reaction chamber such as a riser, optionally mixed with a regenerated catalyst stream (that is to say directly from the regeneration chamber).
  • the object of the present invention is to remedy these shortcomings of the prior art by proposing a series of distinct reaction zones that can operate under conditions of temperature and C / O very different. More specifically, the invention relates to a method of catalytic cracking composed of a reaction zone having at least two reactors, with in at least one of these reactors a flow of fluids and catalyst globally downstream (dropper reactor) and in at least one of these reactors a fluid flow and generally upward catalyst (reactor riser), these reactors being characterized by the fact that in each reactor, hydrocarbons introduced into the reactor are brought into contact with hot catalyst which allows the vaporization of these hydrocarbons if they are introduced in liquid form, these vaporized hydrocarbons reacting in the presence of the catalyst, these reacted hydrocarbons are then separated from the catalyst by separation means (inertial separators and / or cyclones) and leave the reaction zone to undergo the usual downstream treatments (fractionation, ). Reactors are also characterized by the fact that the downstream reactor (s) is followed by at least one up
  • the invention relates to a process for catalytic cracking in a bed or fluidized a hydrocarbon feedstock in two reaction zones, one to flow downstream catalyst, the other catalyst upflow, the process being characterized in that a feedstock and catalyst from at least one zone are introduced regeneration in the upper part of the downflow zone, circulate the filler and catalyst in said zone in a weight ratio: catalyst on filler C / O: 5 to 20, the cracked gases are separated from the coked catalyst from the flow zone descending into a first separation zone, the cracked gases are recovered, the coked catalyst in the lower part of the upflow zone, a charge in the lower part of said upflow zone, circulates the coked catalyst and said feedstock in a weight ratio C / O: 4 to 8, the catalyst is separated off wastewater produced in a second separation zone, the catalyst is stripped means of a gas filling in a stripping zone, the effluent and the gases of stripping and the used catalyst is recycled to the regeneration zone where it is regenerated at less in part by means of a regeneration gas
  • the residence times of the load in the dropper and the riser are respectively in general from 50 to 650 ms in the dropper and from 600 to 3000 ms in the nser and preferably 100 to 500 m s in the dropper and 1000 to 2500 ms in the riser.
  • the residence time is defined as the ratio of the volume of each of the reaction chambers (riser or dropper), referred to volume flow rate of the gaseous effluents from each chamber under the exit conditions.
  • the spent catalyst can be regenerated in two zones of superimposed regeneration, the spent catalyst to be regenerated is introduced into a first zone regeneration, the catalyst thus at least partially regenerated being sent to the second upper regeneration zone and the regenerated catalyst from the zone of Higher regeneration is introduced into the downflow zone.
  • the catalyst / oil ratio (C / O) may advantageously be between 7 and 15 for downflow reactor and between 5 and 7 for the upflow reactor.
  • the catalyst temperature at the outlet of the dropper is generally greater than that at the outlet of the riser. It may be from 500 ° C. to 700 ° C. and advantageously from 550 ° C. to 600 ° C. while that of the catalyst at the riser outlet may be from 500 ° C. to 550 ° C. and advantageously from 515 ° C to 530 ° C. These temperatures are closely dependent on the values of the ratios of the C / O, the C / O ratio of the dropper being higher than that of the user.
  • the feedstock supplying each of the reactors can be either a fresh load, ie a recycling of some of the products resulting from a fractionation downstream, or a mixture of both.
  • the charge can be injected co-currently or countercurrently into each of the two reactors.
  • the charge flow rate, for example, of recycle, in the Downstream reactor may be less than 50% by mass of the charge rate to be converted circulating in the riser reactor.
  • the invention also relates to the device for implementing the method. It generally comprises a first substantially vertical downflow reactor having an upper inlet and a lower outlet, first regenerated catalyst feed means connected to at least one spent catalyst regenerator and connected to said upper inlet, first atomized charge feed means disposed below the first catalyst feed means, a first chamber for separating the catalyst from a gas phase connected to the lower outlet of the first downstream reactor and having a gas phase outlet and a coked catalyst outlet, a second substantially vertical upflow reactor having a lower inlet and an upper outlet, a second catalyst supply means being connected to the coked catalyst outlet of the first separation chamber and to the lower inlet of the second reactor, second feed means in a feed located above the lower inlet of the second reactor, a second spent catalyst separation chamber and a second gas phase connected to said upper outlet of the second reactor, said second chamber having a catalyst stripping chamber and having an upper gas phase outlet and a lower catalyst outlet used, said lower output being connected to the regenerator.
  • FIG. 1 attached is a representation of the process under these conditions.
  • the catalyst regenerated in a regeneration zone (3) is transported to the inlet of a reactor globally descending by transfer means (4), withdrawn from the downstream reactor by means of transport (5) and introduced into an upstream reactor (2), then having traveled the reactor ascending, is transported by a line (7) to the regeneration zone (3).
  • the reactor ascendant can also be supplied with freshly regenerated catalyst by means (6) transporting the catalyst from the regeneration zone downward of the upstream reactor (2).
  • the load supplying each of the reactors can be either a fresh charge (line (8) for the downstream reactor, line (9) for the upstream reactor), or a recycle of a part of products from the downstream fractionation (line (16) for the downstream reactor, line (14) for the riser reactor), a mixture of both. It is possible to introduce in each reactor of the recycles of the fractionation independently of the means of introduction of the cool load (line (15) for the downstream reactor, line (13) for the upstream reactor).
  • the gaseous effluents from each reactor are transported to a zone of fractionation (10) of the various hydrocarbon cuts by conduits (11) for downstream reactor and (12) for the upstream reactor).
  • Figure 1 there is shown a arrangement where the fractionation is common to both reaction chambers.
  • the fractionation is independent for each of the reactors, which may be of great interest if the operating conditions of the two reaction zones are very different from each other. Indeed, in this case, the yield structures very different can economically justify the interest of effluent fractionation adapted to each of the reaction chambers.
  • FIG. 2 describes a possible arrangement of the various constituents of the process the invention. It is indeed necessary for the catalyst to circulate correctly between the different speakers that the pressures of each of the speakers are compatible with the rates of catalyst and hydrocarbon circulation desired in each of the enclosures.
  • the regeneration zone (3) consists of two enclosures (301) and (302) in which the catalyst is regenerated in a fluidized bed, air being introduced into each chamber.
  • the catalyst is transported between the two chambers by means of a lift (303), in which gas introduced at the base at a sufficient speed can transport the catalyst between the two speakers. This transport gas can be air.
  • the proportion of air needed to the regeneration is 30 to 70% in the enclosure (301), 5 to 20% in the lift (303) in order to transport the catalyst and 15 to 40% in the enclosure (302).
  • the Gaseous flue gases are dusted off by passing through separators (such as cyclones, shown here schematically (306 and 307).
  • separators such as cyclones, shown here schematically (306 and 307).
  • each enclosure (301) and (302) can be controlled by valves on the lines allowing the evacuation of combustion effluents, at least partially dusted.
  • FIG 2 shows how it is possible to transfer catalyst from a regeneration chamber (302) to the reactor (1).
  • the catalyst is withdrawn into a wall through an inclined line (304) of an angle generally between 30 and 70 ° with respect to the horizontal conducting the catalyst to a enclosure (305) in which the circulation of the catalyst is slowed down to allow evacuation any gas bubbles to the regeneration chamber through a balancing line (308).
  • the catalyst is then accelerated and descends through a transfer tube (309) to the reactor inlet.
  • the catalyst is maintained in the fluidized state through the addition of small amounts of gas throughout the transport. If the catalyst is thus maintained in a fluid state, this makes it possible to obtain at the entrance to the zone reaction (1) a pressure higher than that of smoke from external cyclones (307).
  • the reaction zone (1) defined as descending generally consists of means for introducing the catalyst (101), which may be a valve on a solid, an orifice, or simply opening a conduit, a contacting zone (103) located under (101) where the countercurrent catalyst, for example, encounters the hydrocarbon feed introduced by means (102), generally consisting of atomizers where the charge is finely divided into droplets usually using the introduction of auxiliary fluids such as steam of water.
  • the means for introducing the catalyst are located above the means introduction of the charge.
  • an area may optionally be reaction tube (104), of substantially elongate shape, shown vertically on the Figure 2 but this condition is not exclusive.
  • the average residence time of hydrocarbons in zones 103 to 104 will be less than 650 ms, preferably between 50 and 500ms.
  • the effluents of the dropper are then separated in a separator (105) described in application FR98 / 09672 incorporated as a reference where the residence time must be limited to maximum.
  • the gaseous effluents (cracked gases) of the separator can then undergo a step additional dedusting through external cyclones (108) arranged downstream on a line (106).
  • the gaseous effluents (cracked gases) are evacuated by a line (107).
  • the catalyst in the fluidized bed (111) then undergoes stripping (contact with a light gas such as steam, nitrogen, ammonia, hydrogen or even hydrocarbons whose number of carbon atoms is less than 3 (by means which are well described in the prior art) before being transferred to the upward reaction zone (2) through the conduit (110).
  • a light gas such as steam, nitrogen, ammonia, hydrogen or even hydrocarbons whose number of carbon atoms is less than 3 (by means which are well described in the prior art
  • Effluents gaseous stripping is generally removed from the fluidized bed (111) through the same means (106) and (108) which allow the evacuation of gaseous effluents from the zone reaction (1) via line (107). All effluents can be cooled by means of quench (not shown) on lines (106) or (107)
  • the reaction zone (2) is a substantially elongated tubular zone, many of which Examples are described in the prior art.
  • the load of hydrocarbons is introduced by means (202), generally consisting of atomizers where the charge is finely divided into droplets, usually using the introduction of fluids auxiliaries such as water vapor, introduced at the base of the reactor.
  • Means of introduction catalyst are located below the feed introduction means.
  • the introduction of the charge must be located above at least one catalyst inlet.
  • all the catalyst comes from the downstream reactor and the charge introduction means are therefore located above the pipe (110).
  • the upstream reactor will then be fed by several catalyst streams, at least one from a reactor descending.
  • the reaction is then carried out in the tubular or riser reactor (201).
  • the effluents from the riser are then separated in a separator (203) such as that described in FIG. (2) and in PCTFR application 98/01866 incorporated as a reference.
  • the catalyst from the separation (203) is then introduced into a fluidized bed (211) of a stripping chamber (212) through conduits or openings (204).
  • the catalyst in (211) is then stripped (contact with a light gas such as water vapor, nitrogen, ammonia, hydrogen or even hydrocarbons with less than 3 carbon atoms means which are well described in the prior art) before being transferred to the regeneration (301) through conduits (7).
  • the reaction gaseous effluents separated in (203) are discharged through a conduit (205) to a secondary separator (207) such that a cyclone before being directed to the fractionation section (10) via a conduit (206).
  • the stripping gaseous effluents are generally discharged from the fluidized bed (211) through the same means (206) which allow the evacuation of gaseous effluents from the zone reactional (2).
  • the coked catalyst is withdrawn from the stripping chamber (212) and recycled in the first regeneration chamber (301), located under the chamber 302 regeneration.

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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)

Abstract

An entrained bed or fluidised bed process for catalytic cracking of a hydrocarbon feed in two reaction zones is described, one zone (1) being in catalyst dropper mode, the other (2) being in catalyst riser mode. A feed (102) and catalyst from at least one regeneration zone (302) are introduced into the upper portion of the dropper zone, the feed and catalyst are circulated in accordance with a catalyst to feed weight ratio, C/O, of 5 to 20, the cracked gases are separated from the coked catalyst in a first separation zone (105), the cracked gases are recovered (107), the coked catalyst is introduced (110) into the lower portion of the riser zone (2), the coked catalyst and said feed are circulated in a C/O weight ratio of 4 to 8, the used catalyst is separated from the effluent produced in a second separation zone (203), the catalyst is stripped in a stripping zone (212), the effluent and stripping gases are recovered (206) and the used catalyst is recycled (7) to the regeneration zone.

Description

La présente invention concerne un procédé et un dispositif pour le craquage catalytique de charges d'nydrocarbures.The present invention relates to a method and a device for the catalytic cracking of hydrocarbon charges.

On sait que l'industrie pétrolière utilise de façon usuelle des procédés de craquage dans lesquels les molécules d'hydrocarbures à poids moléculaire et à point d'ébullition élevés sont scindés en molécules plus petites à point d'ébullition plus faible.It is known that the petroleum industry usually uses cracking processes in high molecular weight and high boiling hydrocarbon molecules are split into smaller molecules with lower boiling point.

Dans les procédés de craquage catalytique récents, décrits par exemple dans le brevet EP-A-291253, la réaction de craquage a lieu dans une enceinte allongée de section sensiblement circulaire, le catalyseur étant admis à la partie inférieure de l'enceinte ainsi que la charge hydrocarbonée préalablement atomisée. La mise en contact de la charge avec le catalyseur chaud permet de vaporiser les hydrocarbures qui entraínent alors le catalyseur vers la partie supérieure de la zone réactionnelle, l'introduction d'un fluide d'entraínement aidant le mouvement ascendant. Les produits formés au cours de la réaction ont une gamme de points d'ébullition très large. On distingue généralement les produits formés en fonction de leur température d'ébullition et de leur nature chimique : gaz secs H2, H2S, molécules possédant 1 ou 2 atomes de carbones GPL (gaz de pétrole liquéfiés) molécules possédant 3 ou 4 atomes de carbone Essence molécules ayant au moins 5 atomes de carbone et dont le point d'ébullition est inférieur à 220 °C LCO (light cycle oil) molécules dont le point d'ébullition est supéneur à 220 °C et inférieur à 360 °C Slurry molécules dont le point d'ébullition est supérieur à 360 °C coke molécules lourdes (généralement polyaromatiques restant adsorbées sur le catalyseur après la réaction). In the recent catalytic cracking processes, described for example in the patent EP-A-291253, the cracking reaction takes place in an elongated enclosure of substantially circular cross section, the catalyst being admitted to the lower part of the enclosure and the hydrocarbon feed previously atomized. The contacting of the feedstock with the hot catalyst makes it possible to vaporize the hydrocarbons which then drive the catalyst towards the upper part of the reaction zone, the introduction of a driving fluid aiding the upward movement. The products formed during the reaction have a very wide range of boiling points. The products formed are generally distinguished according to their boiling point and their chemical nature: dry gases H2, H2S, molecules having 1 or 2 carbon atoms LPG (liquefied petroleum gases) molecules with 3 or 4 carbon atoms gasoline Molecules having at least 5 carbon atoms and boiling in less than 220 ° C LCO (light cycle oil) molecules whose boiling point is greater than 220 ° C and less than 360 ° C slurry molecules boiling in excess of 360 ° C coke heavy molecules (generally polyaromatic remaining adsorbed on the catalyst after the reaction).

Les points d'ébullition servant à délimiter les coupes sont donnés à titre indicatif et correspondent aux valeurs standard généralement admises. Néanmoins, ces points de coupe peuvent varier en fonction des besoins des raffineurs, qui, dans certains cas forment de plus des coupes intermédiaires des produits formés.The boiling points used to delimit the cuts are given for information only and correspond to the standard values generally accepted. Nevertheless, these cutting points may vary according to the needs of the refiners, who in some cases form more intermediate cuts of the products formed.

Les rendements que l'on obtient généralement dépendent naturellement de la qualité des charges traitées. Typiquement, à titre indicatif, les rendements observés (en % poids de la charge) sur les unités sont : gaz sec 1-5 % GPL 10-25 % Essence 30-55 % LCO 15-25% Slurry 5-20 % coke 3-10 % The yields that are generally obtained naturally depend on the quality of the treated feeds. Typically, as an indication, the observed yields (in% weight of the load) on the units are: dry gas 1-5% LPG 10-25% gasoline 30-55% OCH 15-25% slurry 5-20% coke 3-10%

Généralement, le coke formé est brûlé dans une ou plusieurs enceintes appelées régénérateurs vers lesquelles le catalyseur circule à sa sortie du réacteur. La chaleur produite par la combustion du coke permet de réchauffer le catalyseur qui est ensuite réintroduit à l'entrée du réacteur et mis en contact avec la charge. Le procédé de craquage catalytique est un procédé adiabatique. La chaleur récupérée par le catalyseur lors de son passage dans la zone de régénération est égale à la chaleur perdue par le catalyseur lors de son passage dans la zone réactionnelle. Cela impose donc à l'opérateur des conditions opératoires non indépendantes les unes des autres. Les conditions opératoires qui affectent le plus rendements et sélectivités pour un réacteur donné sont essentiellement le débit de catalyseur, que l'on rapporte généralement au débit de charge sous l'appellation C/O (C pour Catalyst et O pour Oil). Le domaine habituel d'opération des unités de craquage catalytique est généralement : C/O= 4-8 (C/O= rapport massique du débit de catalyseur sur le débit de charge)    T(au sommet du réacteur)=500-550 °CGenerally, the formed coke is burned in one or more chambers called regenerators to which the catalyst flows at its outlet from the reactor. The heat produced by the combustion of the coke makes it possible to heat the catalyst, which is then reintroduced at the reactor inlet and brought into contact with the feedstock. The catalytic cracking process is an adiabatic process. The heat recovered by the catalyst during its passage through the regeneration zone is equal to the heat lost by the catalyst as it passes through the reaction zone. This therefore imposes on the operator operating conditions that are not independent of each other. The operating conditions that affect the most efficiencies and selectivities for a given reactor are essentially the catalyst flow, which is generally related to the feed rate under the name C / O (C for Catalyst and O for Oil). The usual field of operation of catalytic cracking units is generally: C / O = 4-8 (C / O = mass ratio of catalyst flow to charge flow) T (at the top of the reactor) = 500-550 ° C

On sait que la conversion augmente avec la température et le C/O. Néanmoins, cette augmentation peut entre autre s'accompagner d'une augmentation significative du rendement coke et des gaz secs avec des technologies classiques. L'augmentation du rendement en coke, par le biais de la balance thermique regénérateur-réacteur et du dimensionnement de l'unité, limite souvent l'opérateur à un domaine de conditions opératoires restreint, et pour un type de charge donnée à une structure de rendements assez figée.It is known that the conversion increases with temperature and C / O. Nevertheless, this increase can, among other things, be accompanied by a significant increase in the coke and dry gases with conventional technologies. The increase in coke yield, through the regenerative thermal balance-reactor and the dimensioning of the unit, often limits the operator to a narrow range of operating conditions, and for a type of load given to a fairly fixed yield structure.

Or, les variations des prix de vente des différents produits peuvent fluctuer en fonction du temps, ce qui peut induire au raffineur la volonté de maximiser certains produits au détriment de certains autres. De plus, l'évolution des spécifications imposées sur les produits dans les différents pays fait que certains produits issus du FCC peuvent ne plus trouver de débouché (par exemple, le LCO étant très aromatique et doté d'un très mauvais indice de cétane, son utilisation dans les carburants du pool gazole pose des problèmes, la teneur en soufre de l'essence lourde (160°C-220°C) rend son utilisation dans le pool des essences délicate dans certains cas). Il peut donc être intéressant donc de minimiser également certaines coupes.However, variations in the selling prices of the different products may fluctuate depending on the time, which may induce the refiner to maximize certain products at the expense of some others. Moreover, the evolution of the specifications imposed on the products in the different countries, some products from the FCC may no longer be able to (For example, LCO is very aromatic and has a very poor cetane number. fuel in the diesel fuel pool is problematic, the sulfur content of heavy gasoline (160 ° C-220 ° C) makes its use in the pool of delicate species in certain cases). It may therefore be interesting to minimize some cuts as well.

Il est connu que la maximisation du propylène, produit à haute valeur ajoutée (molécule comprise dans la coupe GPL), passe par une sévérisation des conditions de réactions (plus haute température, plus fort C/O). Or, cette sévérisation impliquera que, dans le même temps, les rendements d'autres coupes baissent (LCO et essence). It is known that the maximization of propylene, a product with high added value (molecule included in the LPG cut), goes through a tightening of the reaction conditions (more high temperature, stronger C / O). However, this severity will imply that, at the same time, the yields of other cuts fall (LCO and gasoline).

En travaillant à basse sévérité, on tendra à maximiser le LCO, ce qui peut présenter un intérêt dans les pays où les distillats moyens sont très demandés sur le marché des combustibles, mais les GPL (dont le propylène) ainsi que l'essence ne seront vraisemblablement pas maximisés.Working at low severity will tend to maximize the OLC, which may be of interest in countries where middle distillates are in high demand in the fuel market, but LPGs (including propylene) and gasoline are unlikely to be maximized.

L'opération de la zone réactionnelle pour une unité conventionnelle n'est donc pas toujours compatible avec la tenue de deux objectifs tels que ces deux exemples non limitatifs :

  • la maximisation du propylène et du LCO
  • la minimisation de l'essence lourde, la maximisation de l'essence légère
The operation of the reaction zone for a conventional unit is therefore not always compatible with the holding of two objectives such as these two non-limiting examples:
  • maximizing propylene and LCO
  • the minimization of heavy gasoline, the maximization of light gasoline

Il y a donc intérêt à trouver des solutions permettant dans une zone réactionnelle d'opérer à la fois à basse sévérité et à haute sévérité, par exemple en utilisant deux zones réactionnelles opérant dans des conditions opératoires différentes.There is therefore interest in finding solutions allowing in a reaction zone to operate at the at low severity and severity, for example using two reaction zones operating under different operating conditions.

Les zones réactionnelles généralement utilisées dans la majorité des unités de craquage catalytique actuelles permettent facilement d'opérer dans des conditions de craquage peu sévères (C/O de 4 à 8 et températures en sortie de réacteur de 500 à 550 °C). Le temps de séjour des hydrocarbures dans cette zone réactionnelle, constituée au minimum d'un tube de section sensiblement circulaire et de forme allongée dans lequel les fluides s'écoulent globalement du bas vers le haut appelé communément riser, et d'un système de séparation des vapeurs de craquage et du catalyseur est généralement supérieur à 2s, de l'ordre de 2 à 10s environ. Le temps de séjour des hydrocarbures au contact du catalyseur est souvent lui-même supérieur à 1 s.The reaction zones generally used in the majority of cracking units current catalytic converters make it easy to operate under conditions of little cracking severe (C / O from 4 to 8 and reactor outlet temperatures of 500 to 550 ° C). Time to hydrocarbon residence in this reaction zone, consisting at least of a tube of substantially circular and elongated section in which the fluids flow globally from bottom to top commonly called riser, and from a separation system cracking vapors and catalyst is generally greater than 2s, of the order of 2 to About 10s. The residence time of the hydrocarbons in contact with the catalyst is often itself greater than 1 s.

La juxtaposition de deux réacteurs conventionnels pour obtenir deux types de conditions opératoires sur une même unité de craquage catalytique, tels que décrits par Niccum P.K., Miller R.B., Claude A. and M.A.Silvermann dans « Maxofin : a novel FCC process for maximizing light olefins using a new generation ZSM5 additive » (1998, NPRA annual meeting, San Francisco, Califomia, USA, 16 march 1998) rend nécessaire l'utilisation d'additifs dans le second riser où la réaction s'effectue dans des conditions plus sévères pour obtenir une sélectivité plus favorable. De plus, les conditions plus sévères dans le second réacteur induisent une augmentation très importante du rendement en coke (plus de 2 % par rapport à la charge). Ce type de système n'est donc pas agencé de manière optimale.The juxtaposition of two conventional reactors to obtain two types of conditions procedures on the same catalytic cracking unit, as described by Niccum P.K., Miller R.B., Claude A. and M.A.Silvermann in "Maxofin: a novel FCC process for maximizing light olefins using a new generation ZSM5 additive "(1998, NPRA annual meeting, San Francisco, Califomia, USA, 16 March 1998) requires the use of additives in the second riser where the reaction is carried out under more severe conditions to obtain a more favorable selectivity. In addition, the more severe conditions in the second reactor induce a very significant increase in the coke yield (over 2% compared to load). This type of system is therefore not optimally arranged.

L'art antérieur peut aussi être illustré par les brevets US-4 424 116 et US 4 606 810 qui décrivent en enchaínement en série de deux réacteurs ascendants. Le brevet US 5 039 395 illustre par ailleurs l'arrière plan technologique. The prior art can also be illustrated by US Pat. Nos. 4,424,116 and 4,606,810. describe in series series of two upstream reactors. U.S. Patent 5,039,395 illustrates the technological background.

Afin de minimiser une coupe, il est également possible, dans une unité possédant une ou plusieurs enceintes réactionnelles conventionnelles de type riser, de recycler dans le riser les produits dont on veut minimiser la production. Cela présente dans le cas des charges lourdes un avantage important pour la balance thermique des unités : la vaporisation du recycle consomme plus de chaleur et permet donc de produire plus de chaleur dans la zone de régénération et donc de produire plus de coke dans la zone réactionnelle ; de plus, astucieusement disposée en aval par rapport à l'injection de charge fraíche, l'injection du recycle permet de favoriser la vaporisation de la charge fraíche, ce qui, là encore, permet de traiter des charges de plus en plus lourdes (dont les points d'ébullition moyen et final sont plus élevés). Un tel dispositif est décrit par exemple pour le craquage des coupes lourdes dans le brevet FR 2 621 322.In order to minimize a cut, it is also possible, in a unit with one or several conventional riser-type reaction chambers, to recycle in the riser the products whose production we want to minimize. This presents in the case of heavy loads an important advantage for the thermal balance of the units: the vaporization of the recycling consumes more heat and thus allows to produce more heat in the zone of regeneration and therefore produce more coke in the reaction zone; Moreover, cleverly arranged downstream from the fresh charge injection, the injection of the recycle allows to promote the vaporization of the fresh load, which, again, allows to deal with increasingly heavy loads (whose average and final boiling points are more high). Such a device is described for example for cracking heavy cuts in the patent FR 2 621 322.

Dans ce type de mise en oeuvre, les produits recyclés ne sont cependant pas exposés à des conditions très sévères et réagissent peu. Le but de ces recycles est plus lié au bilan thermique et à la vaporisation de la charge qu'à la destruction de ces recycles vers des produits plus valorisables.In this type of implementation, however, recycled products are not exposed to very severe conditions and react very little. The purpose of these recycles is more related to the thermal balance and the vaporization of the charge than the destruction of these recycles to more products recoverable.

Il est également possible de mettre en oeuvre ces recycles en amont de la charge, pour les exposer à des conditions plus sévères que la charge. Dans ces conditions néanmoins, les produits formés dans les conditions les plus sévères ont le temps de se dégrader au-dessus de l'injection de charge où le temps de séjour au contact du catalyseur est nécessairement assez long (supérieur à 1-2 s)It is also possible to implement these recycles upstream of the load, for expose to conditions more severe than the load. In these circumstances, however, the products formed under the most severe conditions have time to degrade over the charge injection where the residence time in contact with the catalyst is necessarily enough long (greater than 1-2 s)

Afin d'opérer dans des conditions opératoires plus sévères, il est préférable de travailler avec des temps de séjour des hydrocarbures dans le réacteur qui sont plus courts. En effet, en augmentant la température, les réactions de dégradation thermique des produits sont de plus en plus prépondérantes. Pour limiter leur impact, il faut limiter le temps de séjour des hydrocarbures dans ces conditions. Plus, le temps de séjour est court et plus il est nécessaire de bien contrôler les mécanismes de mise en contact des hydrocarbures et du catalyseur, ainsi que l'hydrodynamique dans le réacteur. Le réacteur descendant, combiné à un système de mélange approprié, tel que décrit dans le brevet WO/FR98/12279 permet d'optimiser les sélectivités en produits valorisables (LPG, essences) en minimisant les produits non valorisables (augmentation minime du coke par rapport à un réacteur conventionnel, mais dans des conditions de température et de C/O très différentes, diminution de 30 % environ des gaz secs par rapport à une technologie conventionnelle) et de maximiser la conversion, grâce à l'obtention de conditions de sévérité très importante.In order to operate under more severe operating conditions, it is preferable to work with hydrocarbon residence times in the reactor which are shorter. Indeed, in increasing the temperature, the thermal degradation reactions of the products are moreover in addition to preponderant. To limit their impact, it is necessary to limit the residence time of hydrocarbons under these conditions. Plus, the residence time is short and the more it is necessary to control the mechanisms of contact between the hydrocarbons and the catalyst, as well as as hydrodynamics in the reactor. The downstream reactor, combined with a mixture, as described in patent WO / FR98 / 12279, makes it possible to optimize the selectivities in recoverable products (LPG, gasolines) by minimizing the products not recoverable (a small increase in coke compared to a conventional reactor, but in very different temperature and C / O conditions, about 30% less gas dry compared to conventional technology) and to maximize conversion, thanks to obtaining conditions of very serious severity.

Il est donc envisageable, pour accroítre la flexibilité d'opération des FCC de disposer d'un enchaínement d'un réacteur descendant avec un réacteur ascendant. Néanmoins, selon le brevet EP-B-573316 décrivant ce dispositif, tous les produits exposés dans le réacteur descendant doivent ensuite passer dans le réacteur ascendant. Le temps de séjour des produits formés dans le réacteur descendant est donc allongé par le temps de parcours dans le réacteur ascendant. De plus, il n'est pas suggéré d'opérer ces deux réacteurs dans des conditions opératoires significativement différentes.It is therefore conceivable, to increase the flexibility of operation of the FCC to have a sequencing of a downflow reactor with an upflow reactor. Nevertheless, according to Patent EP-B-573316 describing this device, all the products exposed in the reactor descendant must then pass into the riser reactor. The residence time of products formed in the downstream reactor is therefore lengthened by the travel time in the rising reactor. Moreover, it is not suggested to operate these two reactors in significantly different operating conditions.

L'avantage essentiel de ce type de dispositif est de pouvoir mettre en contact catalyseur et charge de manière optimale grâce à l'utilisation initiale d'un réacteur descendant.The main advantage of this type of device is to be able to contact catalyst and load optimally through the initial use of a downflow reactor.

La mise en contact des hydrocarbures avec le catalyseur en réacteur descendant lorsqu'elle est effectuée correctement et lorsque le temps de contact entre le catalyseur et les hydrocarbures est limité, permet de minimiser la quantité de coke formé, Il en résulte donc une teneur en coke sur le catalyseur beaucoup plus faible que dans un réacteur ascendant équivalent. Combinée à des conditions opératoires adaptées (circulation de catalyseur plus élevée par rapport à une même quantité de charge), cela peut permettre de réduire la teneur en coke sur le catalyseur de manière très significative, ce qui est particulièrement avantageux pour les charges lourdes, dont le pouvoir cokant est bien connu. De plus on sait que le coke déposé sur le catalyseur tend à désactiver significativement le catalyseur, ce d'autant plus qu'il y a de coke déposé. Typiquement, dans les réacteurs ascendants conventionnels, la quantité de coke présente sur le catalyseur varie entre 0,7 et 1,5 % poids, en fonction de la charge traitée, du catalyseur, des conditions opératoires et du dimensionnement de l'unité. On sait que dans ces conditions, l'activité résiduelle du catalyseur est faible. Il est donc illusoire de vouloir réintroduire ce catalyseur dans une nouvelle enceinte réactionnelle. Par contre, dans le cas d'un réacteur descendant, il est possible de limiter le taux de cokage du catalyseur à des valeurs voisines de 0,2-0,5 % poids dépendant des conditions opératoires, où son activité résiduelle reste importante. Dans ces conditions, le catalyseur issu du réacteur descendant peut avantageusement être à nouveau introduit dans une enceinte réactionnelle telle qu'un riser, éventuellement mélangé à un flux de catalyseur régénéré (c'est-à-dire directement issu de l'enceinte de régénération). On voit donc bien que ces résultats permettent d'envisager sereinement un enchaínement de zones réactionnelles d'abord descendantes, puis ascendantes où le catalyseur issu de la zone réactionnelle descendante serait totalement réintroduit à l'entrée du réacteur ascendant.The contacting of the hydrocarbons with the catalyst in a downstream reactor when it is performed correctly and when the contact time between the catalyst and the hydrocarbons is limited, allows to minimize the amount of coke formed, It therefore results in a coke content on the catalyst much lower than in an equivalent upflow reactor. Combined with suitable operating conditions (higher catalyst circulation compared with same amount of charge), this can reduce the coke content on the catalyst very significantly, which is particularly advantageous for heavy loads, whose cokant power is well known. In addition, it is known that the coke deposited on the catalyst tends to significantly deactivate the catalyst, especially since there is coke deposited. Typically, in conventional upstream reactors, the amount of coke present on the catalyst varies between 0.7 and 1.5% by weight, depending on the feedstock treated, the catalyst, operating conditions and the dimensioning of the unit. We know that under these conditions, the residual activity of the catalyst is low. It is therefore illusory to want to reintroduce catalyst in a new reaction chamber. On the other hand, in the case of a reactor downstream, it is possible to limit the coking rate of the catalyst to values close to 0.2-0.5% weight depending on the operating conditions, where its residual activity remains important. Under these conditions, the catalyst from the downstream reactor can advantageously be introduced again into a reaction chamber such as a riser, optionally mixed with a regenerated catalyst stream (that is to say directly from the regeneration chamber). We can see that these results make it possible to envisage serenely a sequence of reaction zones first descending, then ascending where the catalyst from the downward reaction zone would be totally reintroduced at the entrance of the rising reactor.

L'objet de la présente invention est de remédier à ces lacunes de l'art antérieur en proposant un enchaínement de zones réactionnelles distinctes pouvant opérer dans des conditions de température et de C/O très différentes. Plus précisément, l'invention concerne un procédé de craquage catalytique composé d'une zone réactionnelle présentant au moins deux réacteurs, avec dans l'un au moins de ces réacteurs un écoulement des fluides et du catalyseur globalement descendant (réacteur droppeur) et dans au moins l'un de ces réacteurs un écoulement de fluide et de catalyseur globalement ascendant (réacteur riser), ces réacteurs étant caractérisés par le fait que dans chaque réacteur, des hydrocarbures introduits dans le réacteur sont mis en contact avec du catalyseur chaud qui permet la vaporisation de ces hydrocarbures si ceux-ci sont introduits sous forme liquide, ces hydrocarbures vaporisés réagissant ensuite en présence du catalyseur, ces hydrocarbures ayant réagi sont ensuite séparés du catalyseur par des moyens de séparation (séparateurs inertiels et/ou cyclones) et sortent de la zone réactionnelle pour subir les traitements aval habituels (fractionnement, ...). Les réacteurs sont également caractérisés par le fait que le ou les réacteurs descendants sont suivis d'au moins un réacteur ascendant, tout le catalyseur du ou des réacteur(s) descendant(s) passant alors dans au moins un réacteur ascendant en aval.The object of the present invention is to remedy these shortcomings of the prior art by proposing a series of distinct reaction zones that can operate under conditions of temperature and C / O very different. More specifically, the invention relates to a method of catalytic cracking composed of a reaction zone having at least two reactors, with in at least one of these reactors a flow of fluids and catalyst globally downstream (dropper reactor) and in at least one of these reactors a fluid flow and generally upward catalyst (reactor riser), these reactors being characterized by the fact that in each reactor, hydrocarbons introduced into the reactor are brought into contact with hot catalyst which allows the vaporization of these hydrocarbons if they are introduced in liquid form, these vaporized hydrocarbons reacting in the presence of the catalyst, these reacted hydrocarbons are then separated from the catalyst by separation means (inertial separators and / or cyclones) and leave the reaction zone to undergo the usual downstream treatments (fractionation, ...). Reactors are also characterized by the fact that the downstream reactor (s) is followed by at least one upstream reactor, all the catalyst of the reactor (s) going down then passing into at least one upstream reactor downstream.

Plus particulièrement, l'invention concerne un procédé de craquage catalytique en lit entraíné ou fluidisé d'une charge d'hydrocarbures dans deux zones réactionnelles, l'une à écoulement descendant de catalyseur, l'autre à écoulement ascendant de catalyseur, le procédé étant caractérisé en ce qu'on introduit une charge et du catalyseur provenant d'au moins une zone de régénération dans la partie supérieure de la zone à écoulement descendant, on fait circuler la charge et le catalyseur dans ladite zone selon un rapport pondéral : catalyseur sur charge C/O : 5 à 20, on sépare les gaz craqués du catalyseur coké provenant de la zone à écoulement descendant dans une première zone de séparation, on récupère les gaz craqués, on introduit le catalyseur coké dans la partie inférieure de la zone à écoulement ascendant, on introduit une charge dans la partie inférieure de ladite zone à écoulement ascendant, on y fait circuler le catalyseur coké et ladite charge selon un rapport pondéral C/O : 4 à 8, on sépare le catalyseur usé de l'effluent produit dans une deuxième zone de séparation, on stripe le catalyseur au moyen d'un gaz de stnpage dans une zone de stripage, on récupère l'effluent et les gaz de stripage et on recycle le catalyseur usé dans la zone de régénération où il est régénéré au moins en partie au moyen d'un gaz de régénération.More particularly, the invention relates to a process for catalytic cracking in a bed or fluidized a hydrocarbon feedstock in two reaction zones, one to flow downstream catalyst, the other catalyst upflow, the process being characterized in that a feedstock and catalyst from at least one zone are introduced regeneration in the upper part of the downflow zone, circulate the filler and catalyst in said zone in a weight ratio: catalyst on filler C / O: 5 to 20, the cracked gases are separated from the coked catalyst from the flow zone descending into a first separation zone, the cracked gases are recovered, the coked catalyst in the lower part of the upflow zone, a charge in the lower part of said upflow zone, circulates the coked catalyst and said feedstock in a weight ratio C / O: 4 to 8, the catalyst is separated off wastewater produced in a second separation zone, the catalyst is stripped means of a gas filling in a stripping zone, the effluent and the gases of stripping and the used catalyst is recycled to the regeneration zone where it is regenerated at less in part by means of a regeneration gas.

Les temps de séjour de la charge dans le droppeur et le riser sont respectivement en général de 50 à 650 ms dans le droppeur et de 600 à 3000 ms dans le nser et de préférence 100 à 500 m s dans le droppeur et 1000 à 2500 ms dans le riser. Le temps de séjour est défini comme le rapport du volume de chacune des enceintes réactionnelles (riser ou droppeur), rapportée au débit volumique des effluents gazeux de chaque enceinte dans les conditions de sortie.The residence times of the load in the dropper and the riser are respectively in general from 50 to 650 ms in the dropper and from 600 to 3000 ms in the nser and preferably 100 to 500 m s in the dropper and 1000 to 2500 ms in the riser. The residence time is defined as the ratio of the volume of each of the reaction chambers (riser or dropper), referred to volume flow rate of the gaseous effluents from each chamber under the exit conditions.

Selon une caractéristique du procédé, le catalyseur usé peut être régénéré dans deux zones de régénération superposées, le catalyseur usé à régénérer est introduit dans une première zone de régénération inférieure, le catalyseur ainsi au moins en partie régénéré étant envoyé dans la deuxième zone de régénération supérieure et le catalyseur régénéré provenant de la zone de régénération supérieure est introduit dans la zone d'écoulement descendant.According to one characteristic of the process, the spent catalyst can be regenerated in two zones of superimposed regeneration, the spent catalyst to be regenerated is introduced into a first zone regeneration, the catalyst thus at least partially regenerated being sent to the second upper regeneration zone and the regenerated catalyst from the zone of Higher regeneration is introduced into the downflow zone.

Le rapport catalyseur sur huile (C/O) peut être avantageusement compris entre 7 et 15 pour le réacteur à écoulement descendant et entre 5 et 7 pour le réacteur à écoulement ascendant.The catalyst / oil ratio (C / O) may advantageously be between 7 and 15 for downflow reactor and between 5 and 7 for the upflow reactor.

La température du catalyseur en sortie du droppeur est en général supérieure à celle en sortie du riser. Elle peut être de 500 °C à 700 °C et avantageusement de 550 °C à 600 °C tandis que celle du catalyseur en sortie de riser peut être de 500 °C à 550 °C et avantageusement de 515 °C à 530 °C. Ces températures sont étroitement dépendantes des valeurs des rapports respectifs du C/O, le rapport C/O du droppeur étant plus élevé que celui du user.The catalyst temperature at the outlet of the dropper is generally greater than that at the outlet of the riser. It may be from 500 ° C. to 700 ° C. and advantageously from 550 ° C. to 600 ° C. while that of the catalyst at the riser outlet may be from 500 ° C. to 550 ° C. and advantageously from 515 ° C to 530 ° C. These temperatures are closely dependent on the values of the ratios of the C / O, the C / O ratio of the dropper being higher than that of the user.

Selon une caractéristique du procédé, la charge alimentant chacun des réacteurs peut être soit une charge fraíche, soit un recycle d'une partie des produits issus d'un fractionnement en aval, ou un mélange des deux.According to a characteristic of the process, the feedstock supplying each of the reactors can be either a fresh load, ie a recycling of some of the products resulting from a fractionation downstream, or a mixture of both.

De manière préférée, on peut introduire une charge fraíche dans le réacteur ascendant et ledit recycle au moins en partie dans le réacteur descendant.Preferably, it is possible to introduce a fresh charge into the upstream reactor and said recycles at least partially in the downstream reactor.

Il peut être avantageux d'introduire la charge du réacteur ascendant au-dessus du point d'introduction du catalyseur coké et du point d'introduction du catalyseur régénéré.It may be advantageous to introduce the rising reactor charge over the point introducing the coked catalyst and the point of introduction of the regenerated catalyst.

La charge peut être injectée à co-courant ou à contre-courant dans chacun des deux réacteurs.The charge can be injected co-currently or countercurrently into each of the two reactors.

Selon une caractéristique du procédé, le débit de charge par exemple de recycle, dans le réacteur descendant peut représenter moins de 50 % en masse du débit de charge à convertir circulant dans le réacteur ascendant.According to one characteristic of the method, the charge flow rate, for example, of recycle, in the Downstream reactor may be less than 50% by mass of the charge rate to be converted circulating in the riser reactor.

L'invention concerne aussi le dispositif pour la mise en oeuvre du procédé. Il comporte en règle générale un premier réacteur descendant sensiblement vertical ayant une entrée supérieure et une sortie inférieure,
un premier moyen d'alimentation en catalyseur régénéré connecté à au moins un régénérateur de catalyseur usé et raccordé à ladite entrée supérieure,
un premier moyen d'alimentation en la charge atomisée disposé en dessous des premiers moyens d'alimentation en catalyseur,
une première enceinte de séparation du catalyseur d'une phase gazeuse raccordée à la sortie inférieure du premier réacteur descendant et ayant une sortie de la phase gazeuse et une sortie de catalyseur coké,
un deuxième réacteur ascendant sensiblement vertical ayant une entrée inférieure et une sortie supérieure,
un second moyen d'alimentation en catalyseur étant connecté à la sortie de catalyseur coké de la première enceinte de séparation et à l'entrée inférieure du deuxième réacteur,
un second moyen d'alimentation en une charge située au-dessus de l'entrée inférieure du deuxième réacteur,
une deuxième enceinte de séparation de catalyseur usé et d'une seconde phase gazeuse raccordée à ladite sortie supérieure du deuxième réacteur, ladite deuxième enceinte comportant une chambre de stripage de catalyseur et ayant une sortie supérieure d'une phase gazeuse et une sortie inférieure de catalyseur usé, ladite sortie inférieure étant connectée au régénérateur.The invention also relates to the device for implementing the method. It generally comprises a first substantially vertical downflow reactor having an upper inlet and a lower outlet,
first regenerated catalyst feed means connected to at least one spent catalyst regenerator and connected to said upper inlet,
first atomized charge feed means disposed below the first catalyst feed means,
a first chamber for separating the catalyst from a gas phase connected to the lower outlet of the first downstream reactor and having a gas phase outlet and a coked catalyst outlet,
a second substantially vertical upflow reactor having a lower inlet and an upper outlet,
a second catalyst supply means being connected to the coked catalyst outlet of the first separation chamber and to the lower inlet of the second reactor,
second feed means in a feed located above the lower inlet of the second reactor,
a second spent catalyst separation chamber and a second gas phase connected to said upper outlet of the second reactor, said second chamber having a catalyst stripping chamber and having an upper gas phase outlet and a lower catalyst outlet used, said lower output being connected to the regenerator.

L'invention sera mieux comprise au vu des figures suivantes, parmi lesquelles :

  • la figure 1 montre une description schématique du procédé, l'écoulement du catalyseur étant en trait plein alors que celui des hydrocarbures est en pointillé.
  • la figure 2 illustre schématiquement un dispositif comprenant un droppeur, un séparateur intermédiaire et un riser.
The invention will be better understood in view of the following figures, among which:
  • Figure 1 shows a schematic description of the process, the flow of the catalyst being in full line while that of hydrocarbons is dotted.
  • Figure 2 schematically illustrates a device comprising a dropper, an intermediate separator and a riser.

La figure 1 ci-jointe est une représentation du procédé dans ces conditions. Le catalyseur régénéré dans une zone de régénération (3) est transporté à l'entrée d'un réacteur globalement descendant par des moyens de transfert (4), soutiré du réacteur descendant par des moyens de transport (5) et introduit dans un réacteur ascendant (2), puis, ayant parcouru le réacteur ascendant, est transporté par une ligne (7) vers la zone de régénération (3). Le réacteur ascendant peut également être alimenté en catalyseur fraíchement régénéré par des moyens (6) de transport du catalyseur de la zone de régénération vers le bas du réacteur ascendant (2). La charge alimentant chacun des réacteurs peut être soit une charge fraíche (ligne (8) pour le réacteur descendant, ligne (9) pour le réacteur ascendant), soit un recycle d'une partie des produits issus du fractionnement en aval (ligne (16) pour le réacteur descendant, ligne (14) pour le réacteur ascendant), soit un mélange des deux. Il est possible d'introduire dans chaque réacteur des recycles du fractionnement indépendamment des moyens d'introduction de la charge fraíche (ligne (15) pour le réacteur descendant, ligne (13) pour le réacteur ascendant). Les effluents gazeux issus de chaque réacteur sont transportés vers une zone de fractionnement (10) des différentes coupes d'hydrocarbures par des conduits (11) pour le réacteur descendant et (12) pour le réacteur ascendant). Sur la figure 1, on a représenté un agencement où le fractionnement est commun aux deux enceintes réactionnelles. Néanmoins, il est également possible que le fractionnement soit indépendant pour chacun des réacteurs, ce qui peut présenter un grand intérêt si les conditions opératoires des deux zones réactionnelles sont très différentes les unes des autres. En effet, dans ce cas, les structures de rendement très différentes peuvent économiquement justifier l'intérêt d'un fractionnement des effluents adapté à chacune des enceintes réactionnelles.Figure 1 attached is a representation of the process under these conditions. The catalyst regenerated in a regeneration zone (3) is transported to the inlet of a reactor globally descending by transfer means (4), withdrawn from the downstream reactor by means of transport (5) and introduced into an upstream reactor (2), then having traveled the reactor ascending, is transported by a line (7) to the regeneration zone (3). The reactor ascendant can also be supplied with freshly regenerated catalyst by means (6) transporting the catalyst from the regeneration zone downward of the upstream reactor (2). The load supplying each of the reactors can be either a fresh charge (line (8) for the downstream reactor, line (9) for the upstream reactor), or a recycle of a part of products from the downstream fractionation (line (16) for the downstream reactor, line (14) for the riser reactor), a mixture of both. It is possible to introduce in each reactor of the recycles of the fractionation independently of the means of introduction of the cool load (line (15) for the downstream reactor, line (13) for the upstream reactor). The gaseous effluents from each reactor are transported to a zone of fractionation (10) of the various hydrocarbon cuts by conduits (11) for downstream reactor and (12) for the upstream reactor). In Figure 1, there is shown a arrangement where the fractionation is common to both reaction chambers. However, it is also possible that the fractionation is independent for each of the reactors, which may be of great interest if the operating conditions of the two reaction zones are very different from each other. Indeed, in this case, the yield structures very different can economically justify the interest of effluent fractionation adapted to each of the reaction chambers.

Il peut être avantageux de refroidir en aval de la première zone de séparation et de strippage au moins une partie du produit effluent du réacteur descendant, étant donné sa température de sortie de ce réacteur, par un produit résultant d'un fractionnement aval ou par une partie au moins de l'effluent sortant du réacteur ascendant.It may be advantageous to cool downstream of the first zone of separation and stripping at least a portion of the effluent product from the downstream reactor, given its from this reactor, by a product resulting from a downstream fractionation or by a part at less of the effluent leaving the riser reactor.

La figure 2 décrit un agencement possible des différents constituants du procédé objet de l'invention. Il faut en effet, pour que le catalyseur circule correctement entre les différentes enceintes que les pressions de chacune des enceintes soient compatibles avec les taux de circulation de catalyseur et d'hydrocarbures désirés dans chacune des enceintes. Sur la figure 2, la zone de régénération (3) est constituée de deux enceintes (301) et (302) dans lesquelles le catalyseur est régénéré en lit fluidisé, de l'air étant introduit dans chaque enceinte. Le catalyseur est transporté entre les deux enceintes au moyen d'un lift (303), dans lequel du gaz introduit à la base à une vitesse suffisante permet de transporter le catalyseur entre les deux enceintes. Ce gaz de transport peut être de l'air. Typiquement, la proportion d'air nécessaire à la régénération est de 30 à 70 % dans l'enceinte (301), de 5 à 20 % dans le lift (303) afin de transporter le catalyseur et de 15 à 40 % dans l'enceinte (302). Des moyens (304), tels qu'une vanne sur solide de type « vanne à bouchon » permettent de contrôler le débit de circulation entre les enceintes (301) et (302). Dans chacune des deux enceintes (301) et (302), les effluents gazeux de combustion sont dépoussiérés grâce à un passage dans des séparateurs (tels que des cyclones, représentés ici schématiquement (306 et 307). La pression dans chaque enceinte (301) et (302) peut être contrôlée par des vannes situées sur les lignes permettant l'évacuation des effluents de combustion, au moins partiellement dépoussiérées.FIG. 2 describes a possible arrangement of the various constituents of the process the invention. It is indeed necessary for the catalyst to circulate correctly between the different speakers that the pressures of each of the speakers are compatible with the rates of catalyst and hydrocarbon circulation desired in each of the enclosures. On the face 2, the regeneration zone (3) consists of two enclosures (301) and (302) in which the catalyst is regenerated in a fluidized bed, air being introduced into each chamber. The catalyst is transported between the two chambers by means of a lift (303), in which gas introduced at the base at a sufficient speed can transport the catalyst between the two speakers. This transport gas can be air. Typically, the proportion of air needed to the regeneration is 30 to 70% in the enclosure (301), 5 to 20% in the lift (303) in order to transport the catalyst and 15 to 40% in the enclosure (302). Means (304), such as valve on solid type "plug valve" to control the flow of traffic between the speakers (301) and (302). In each of the two enclosures (301) and (302), the Gaseous flue gases are dusted off by passing through separators (such as cyclones, shown here schematically (306 and 307). each enclosure (301) and (302) can be controlled by valves on the lines allowing the evacuation of combustion effluents, at least partially dusted.

Le catalyseur est ensuite transféré vers les zones réactionnelles. Sur la figure 2, on a représenté un enchaínement de deux zones réactionnelles, l'une étant descendante (1), l'autre en aval étant ascendante (2). Dans cet exemple, tout le catalyseur circulant dans le réacteur (2) circule également dans le réacteur (1). Néanmoins, il est dans certains cas intéressant de mélanger, à l'entrée du riser (2), le catalyseur issu de (1) avec du catalyseur provenant directement de l'enceinte de régénération (3). A titre d'exemple, la figure 2 montre comment il est possible de transférer du catalyseur d'une enceinte (302) de régénération vers le réacteur (1). Le catalyseur est soutiré en paroi à travers une ligne inclinée (304) d'un angle compris généralement entre 30 et 70° par rapport à l'horizontale conduisant le catalyseur jusqu'à une enceinte (305) dans laquelle la circulation du catalyseur est ralentie pour permettre d'évacuer d'éventuelles bulles de gaz vers l'enceinte de régénération à travers une ligne d'équilibrage (308). Le catalyseur est ensuite accéléré et descend à travers un tube de transfert (309) jusqu'à l'entrée du réacteur. Durant tout son trajet depuis l'enceinte de régénération, le catalyseur est maintenu dans l'état fluidisé grâce à l'ajout de petites quantités de gaz tout le long du transport. Si le catalyseur est maintenu ainsi à l'état fluide, cela permet d'obtenir à l'entrée de la zone réactionnelle (1) une pression supérieure à celle des fumées issues des cyclones extemes (307). La zone réactionnelle (1) définie comme descendante est généralement constituée de moyens d'introduction du catalyseur (101), qui peuvent être une vanne sur solide, un orifice, ou simplement l'ouverture d'un conduit, d'une zone de mise en contact (103) située sous (101) où le catalyseur rencontre à contre-courant par exemple la charge d'hydrocarbures, introduite par des moyens (102), généralement constitués d'atomiseurs où la charge est divisée finement en gouttelettes à l'aide généralement de l'introduction de fluides auxiliaires tels que la vapeur d'eau. Les moyens d'introduction du catalyseur sont situés au-dessus des moyens d'introduction de la charge. Entre la zone de mise en contact (103) et des moyens de séparation des hydrocarbures du catalyseur (105), on peut éventuellement disposer une zone de réaction (104), de forme sensiblement allongée, représentée de manière verticale sur la figure 2 mais cette condition n'est pas exclusive. Le temps de séjour moyen des hydrocarbures dans les zones 103 à 104 sera inférieur à 650 ms, préférentiellement compris entre 50 et 500ms. Les effluents du droppeur sont ensuite séparés dans un séparateur (105) décrit dans la demande FR98/09672 incorporée comme référence où le temps de séjour doit être limité au maximum. Les effluents gazeux (gaz craqués) du séparateur peuvent alors subir une étape supplémentaire de dépoussièrage à travers des cyclones externes (108) disposés en aval sur une ligne (106). Les effluents gazeux (gaz craqués) sont évacués par une ligne (107). Il est également possible de refroidir les effluents gazeux, afin de limiter la dégradation thermique des produits, en injectant par exemple des hydrocarbures liquides dans l'effluent sortant des cyclones (108) par la ligne (107). Le catalyseur séparé dans le séparateur (105) est alors soit réinjecté directement à la base d'un réacteur ascendant (201) à travers un conduit (110), comme il est indiqué sur la figure 2, soit introduit dans un lit fluidisé (111) d'une charge de stripage à travers un conduit ou une ouverture (109). Le catalyseur dans le lit fluidisé (111) subit alors un stripage (contactage avec un gaz léger tel que- la vapeur d'eau, l'azote, l'ammoniac, l'hydrogène ou même des hydrocarbures dont le nombre d'atomes de carbones est inférieur à 3 (par des moyens qui sont bien décrits dans l'art antérieur) avant d'être transféré vers la zone réactionnelle ascendante (2) à travers le conduit (110). Les effluents gazeux de stripage sont généralement évacués du lit fluidisé (111) à travers les mêmes moyens (106) et (108) qui permettent l'évacuation des effluents gazeux de la zone réactionnelle (1) par la ligne (107). Tous les effluents peuvent être refroidis par des moyens de quench (non représentés) sur les lignes (106) ou (107)The catalyst is then transferred to the reaction zones. In Figure 2, we have represented a sequence of two reaction zones, one being descending (1), the other downstream being ascending (2). In this example, all the catalyst circulating in the reactor (2) also circulates in the reactor (1). Nevertheless, it is in some cases interesting to mix, at the riser inlet (2), the catalyst from (1) with catalyst from directly from the regeneration chamber (3). For example, Figure 2 shows how it is possible to transfer catalyst from a regeneration chamber (302) to the reactor (1). The catalyst is withdrawn into a wall through an inclined line (304) of an angle generally between 30 and 70 ° with respect to the horizontal conducting the catalyst to a enclosure (305) in which the circulation of the catalyst is slowed down to allow evacuation any gas bubbles to the regeneration chamber through a balancing line (308). The catalyst is then accelerated and descends through a transfer tube (309) to the reactor inlet. During its entire journey from the regeneration chamber, the catalyst is maintained in the fluidized state through the addition of small amounts of gas throughout the transport. If the catalyst is thus maintained in a fluid state, this makes it possible to obtain at the entrance to the zone reaction (1) a pressure higher than that of smoke from external cyclones (307). The reaction zone (1) defined as descending generally consists of means for introducing the catalyst (101), which may be a valve on a solid, an orifice, or simply opening a conduit, a contacting zone (103) located under (101) where the countercurrent catalyst, for example, encounters the hydrocarbon feed introduced by means (102), generally consisting of atomizers where the charge is finely divided into droplets usually using the introduction of auxiliary fluids such as steam of water. The means for introducing the catalyst are located above the means introduction of the charge. Between the contacting zone (103) and means of separation of the hydrocarbons from the catalyst (105), an area may optionally be reaction tube (104), of substantially elongate shape, shown vertically on the Figure 2 but this condition is not exclusive. The average residence time of hydrocarbons in zones 103 to 104 will be less than 650 ms, preferably between 50 and 500ms. The effluents of the dropper are then separated in a separator (105) described in application FR98 / 09672 incorporated as a reference where the residence time must be limited to maximum. The gaseous effluents (cracked gases) of the separator can then undergo a step additional dedusting through external cyclones (108) arranged downstream on a line (106). The gaseous effluents (cracked gases) are evacuated by a line (107). It is It is also possible to cool the gaseous effluents, in order to limit the thermal degradation by injecting, for example, liquid hydrocarbons into the effluent leaving the cyclones (108) through the line (107). The catalyst separated in the separator (105) is then either reinjected directly to the base of an upflow reactor (201) through a conduit (110), as shown in FIG. 2, or introduced into a fluidized bed (111) with a charge of stripping through a conduit or opening (109). The catalyst in the fluidized bed (111) then undergoes stripping (contact with a light gas such as steam, nitrogen, ammonia, hydrogen or even hydrocarbons whose number of carbon atoms is less than 3 (by means which are well described in the prior art) before being transferred to the upward reaction zone (2) through the conduit (110). Effluents gaseous stripping is generally removed from the fluidized bed (111) through the same means (106) and (108) which allow the evacuation of gaseous effluents from the zone reaction (1) via line (107). All effluents can be cooled by means of quench (not shown) on lines (106) or (107)

La zone réactionnelle (2) est une zone tubulaire sensiblement allongée, dont de nombreux exemples sont décrits dans l'art antérieur. Dans l'exemple donné sur la figure 2, la charge d'hydrocarbures est introduite par des moyens (202), généralement constitués d'atomiseurs où la charge est divisée finement en gouttelettes, à l'aide généralement de l'introduction de fluides auxiliaires tels que la vapeur d'eau, introduits à la base du réacteur. Des moyens d'introduction du catalyseur sont situés au-dessous des moyens d'introduction de la charge. Pour que la zone réactionnelle soit considérée comme ascendante, il faut que l'introduction de la charge soit située au-dessus d'au moins une entrée de catalyseur. Dans le cas de la figure 2, tout le catalyseur provient du réacteur descendant et les moyens d'introduction de la charge sont donc situés au-dessus de la conduite (110). Dans le cas contraire, le réacteur ascendant sera alors alimenté par plusieurs courants de catalyseur, l'un au moins provenant d'un réacteur descendant. Il sera alors possible de positionner l'introduction de charge (202) au-dessus d'au moins une alimentation en catalyseur (provenant par exemple de la zone de régénération) et en-dessous d'au moins une alimentation en catalyseur (provenant par exemple d'un réacteur descendant). La réaction s'effectue ensuite dans le réacteur tubulaire ou riser (201). Les effluents du riser sont ensuite séparés dans un séparateur (203) tel que celui décrit sur la figure (2) et dans la demande PCTFR 98/01866 incorporée comme référence. Le catalyseur issu de la séparation (203) est alors introduit dans un lit fluidisé (211) d'une chambre de stripage (212) à travers des conduits ou des ouvertures (204). Le catalyseur dans (211) subit alors un stripage (contactage avec un gaz léger tel que la vapeur d'eau, l'azote, l'ammoniac, l'hydrogène ou même des hydrocarbures dont le nombre d'atomes de carbones est inférieur à 3 par des moyens qui sont bien décrits dans l'art antérieur) avant d'être transféré vers la zone de régénération (301) à travers des conduits (7). Les effluents gazeux réactionnels séparés dans (203) sont évacués à travers un conduit (205) vers un séparateur secondaire (207) tel qu'un cyclone avant d'être dirigés vers la section de fractionnement (10) par un conduit (206). Les effluents gazeux de stripage sont généralement évacués du lit fluidisé (211) à travers les mêmes moyens (206) qui permettent l'évacuation des effluents gazeux de la zone réactionnelle (2).The reaction zone (2) is a substantially elongated tubular zone, many of which Examples are described in the prior art. In the example given in Figure 2, the load of hydrocarbons is introduced by means (202), generally consisting of atomizers where the charge is finely divided into droplets, usually using the introduction of fluids auxiliaries such as water vapor, introduced at the base of the reactor. Means of introduction catalyst are located below the feed introduction means. For the zone reaction is considered as ascending, the introduction of the charge must be located above at least one catalyst inlet. In the case of Figure 2, all the catalyst comes from the downstream reactor and the charge introduction means are therefore located above the pipe (110). In the opposite case, the upstream reactor will then be fed by several catalyst streams, at least one from a reactor descending. It will then be possible to position the charge introduction (202) over at less a catalyst feed (eg from the regeneration zone) and below at least one catalyst supply (for example from a reactor descending). The reaction is then carried out in the tubular or riser reactor (201). The effluents from the riser are then separated in a separator (203) such as that described in FIG. (2) and in PCTFR application 98/01866 incorporated as a reference. The catalyst from the separation (203) is then introduced into a fluidized bed (211) of a stripping chamber (212) through conduits or openings (204). The catalyst in (211) is then stripped (contact with a light gas such as water vapor, nitrogen, ammonia, hydrogen or even hydrocarbons with less than 3 carbon atoms means which are well described in the prior art) before being transferred to the regeneration (301) through conduits (7). The reaction gaseous effluents separated in (203) are discharged through a conduit (205) to a secondary separator (207) such that a cyclone before being directed to the fractionation section (10) via a conduit (206). The stripping gaseous effluents are generally discharged from the fluidized bed (211) through the same means (206) which allow the evacuation of gaseous effluents from the zone reactional (2).

Le catalyseur coké est soutiré de la chambre de stripage (212) et recyclé dans la première enceinte de régénération (301), située sous l'enceinte 302 de régénération.The coked catalyst is withdrawn from the stripping chamber (212) and recycled in the first regeneration chamber (301), located under the chamber 302 regeneration.

En disposant astucieusement les enceintes les unes par rapport aux autres, il est possible de faire fonctionner le procédé correctement tout en maintenant les effluents dans la ligne (106) et dans la ligne (206) à la même pression imposée en aval de la colonne de fractionnement, sans disposer de vanne de contrôle de pression différentielle des lignes (106) et (206).By cleverly arranging the speakers in relation to each other, it is possible to operate the process correctly while maintaining the effluents in the line (106) and in the line (206) at the same pressure imposed downstream of the fractionation column, without have differential pressure control valve lines (106) and (206).

A titre d'exemple et pour illustrer l'intérêt de l'invention, on a comparé les résultats obtenus par une unité industrielle munie d'un réacteur ascendant classique (cas A) traitant une charge lourde et équipée d'un système de double régénération tel que décrit sur la figure 2 avec les résultats que l'on obtiendrait en insérant un réacteur descendant en amont de ce réacteur dans deux cas. Dans le premier cas (cas B), on a considéré un enchaínement de deux zones réactionnelles sans séparation des vapeurs d'hydrocarbures en sortie du réacteur descendant. Il est alors nécessaire d'injecter toute la charge fraíche à l'entrée du réacteur descendant. Dans le deuxième cas (cas C), le réacteur descendant est alimenté par la coupe LCO produite par le réacteur ascendant avec séparation des vapeurs d'hydrocarbures en sortie du réacteur descendant tandis que le réacteur ascendant est alimenté par la charge fraíche. Cela permet de découpler totalement les conditions opératoires de ces deux réacteurs, et comme on le voit dans la structure de rendements globale réacteur descendant + réacteur ascendant rapportée à la charge fraíche, d'obtenir une minimisation du rendement LCO au profit de l'essence et des LPG, beaucoup plus avantageuse que dans le cas d'un enchaínement tel que celui du cas B. Ce changement de sélectivités se fait avec une légère augmentation de la production de gaz secs et de coke, minimisée toutefois grâce à l'emploi de la technologie du réacteur descendant à court temps de séjour.By way of example and to illustrate the interest of the invention, the results obtained by an industrial unit equipped with a conventional upstream reactor (case A) treating a load heavy and equipped with a dual regeneration system as described in Figure 2 with the results that would be obtained by inserting a downstream reactor upstream of this reactor into two cases. In the first case (case B), we considered a sequence of two zones reaction without separation of the hydrocarbon vapors at the outlet of the downstream reactor. It is then necessary to inject all the fresh load at the entrance of the downstream reactor. In the second case (case C), the downstream reactor is fed by the LCO cut produced by the rising reactor with separation of hydrocarbon vapors at the reactor outlet descending while the rising reactor is fed by the fresh load. This allows to completely decouple the operating conditions of these two reactors, and as we see in the overall yield structure downstream reactor + upstream reactor reported to the fresh load, to achieve a minimization of the LCO yield in favor of gasoline and LPG, much more advantageous than in the case of a sequence like that of case B. This change of selectivities is done with a slight increase in gas production dry and coke, however minimized through the use of downstream reactor technology short stay time.

On voit par ailleurs que le taux de recycle selon le cas C est substantiellement diminué pour maintenir une température de sortie du catalyseur et d'effluents du riser à une valeur comparable.

Figure 00120001
It can also be seen that the recycling rate according to case C is substantially reduced in order to maintain an exit temperature of the catalyst and of the effluents from the riser at a comparable value.
Figure 00120001

Dans l'exemple, les notations suivantes ont été adoptées.In the example, the following notations were adopted.

On note
   RA = réacteur ascendant
   RD = réacteur descendant
   REG1 : première enceinte de régénération
   REG2 : deuxième enceinte de régénération
   CUFCC : charge fraíche totale à l'entrée de l'unité de FCC.
   C/O (catalyseur sur huile)We notice
RA = upstream reactor
RD = downstream reactor
REG1 : first regeneration chamber
REG2 : second regeneration chamber
CUFCC: full charge at the entrance of the FCC unit.
C / O (oil catalyst)

Les propriétés de la charge d'hydrocarbures considérées sont :

  • densité : d 15 / 4 = 0,934
  • teneur en soufre : %S = 0,5
  • Carbone Conradson : 5,6
    • The properties of the hydrocarbon feed considered are:
  • density: d 15/4 = 0.934
  • Sulfur content:% S = 0.5
  • Conradson Carbon: 5.6

    • Claims (17)

    1. An entrained bed or fluidised bed process for catalytic cracking of a hydrocarbon feed in two reaction zones, one zone (1) in catalyst dropper mode, the other (2) in catalyst riser mode, the process being characterized in that a feed (102) and catalyst from at least one regeneration zone (302) are introduced into the upper portion of the dropper zone, the feed and catalyst are circulated in said zone in a catalyst to feed weight ratio, C/O, of 5 to 20 with a residence time lower than 650 ms, the cracked gases and coked catalyst from the dropper zone are separated in a first separation zone (105), the cracked gases are recovered (107), the coked catalyst is introduced into the lower portion of the riser zone, a feed is introduced (202) into the lower portion of said riser zone (2), the coked catalyst and said feed are circulated in a C/O weight ratio of 4 to 8, the used catalyst is separated from the effluent produced in a second separation zone (203), the catalyst is stripped using a stripping gas in a stripping zone (212), the effluent and stripping gases are recovered (206) and the used catalyst is recycled (7) to the regeneration zone where it is at least partially regenerated using a regeneration gas.
    2. A process according to claim 1, in which the feed residence time in the dropper reactor is from 100 up to 500 ms, and the feed residence time in the riser reactor is from 800 up to 3000 ms, preferably 1000 up to 2500 ms.
    3. A process according to claim 1 or claim 2, in which the used catalyst is regenerated in two superimposed regeneration zones, the used catalyst to be regenerated being introduced into a first lower regeneration zone, the at least partially regenerated catalyst being sent to the second, upper regeneration zone and the regenerated catalyst from the upper regeneration zone being introduced into the dropper reactor.
    4. A process according to any one of claims 1 to 3, in which the catalyst to oil (C/O) ratio is in the range 7 to 15 for the dropper reactor and in the range 5 to 7 for the riser reactor.
    5. A process according to any one of claims 1 to 4, in which the feed supplying each reactor is a fresh feed, a recycle of a portion of the products from downstream fractionation, or a mixture of the two.
    6. A process according to any one of claims 1 to 5, in which the coked catalyst from the dropper zone is stripped using a gas after having been separated and before being introduced into the riser reactor, and the stripping gas is recovered.
    7. A process according to any one of claims 1 to 6, in which the riser reaction zone is also supplied by regenerated catalyst.
    8. A process according to claim 7, in which the feed is introduced between the two points for introducing regenerated catalyst and coked catalyst into the riser zone.
    9. A process according to claim 7, in which the feed is introduced above the point for introducing coked catalyst and the point for introducing regenerated catalyst into the riser reactor.
    10. A process according to any one of claims 1 to 9, in which a fresh feed is introduced into the riser reactor and at least a portion of said recycle is introduced into the dropper reactor.
    11. A process according to any one of claims 1 to 10, in which the feed flow rate and preferably the recycle into the dropper reactor represent less than 50% by weight of the flow rate of the feed to be converted circulating in the riser reactor.
    12. An apparatus for fluidised bed or entrained bed catalytic cracking of a hydrocarbon feed comprising:
      a first substantially vertical dropper reactor (1) with an upper inlet and a lower outlet;
      a first means (101) for supplying regenerated catalyst connected to at least one regenerator for used catalyst and connected to said upper inlet;
      a first means (102) for supplying atomised feed disposed below the first catalyst supply means;
      a first vessel (105) for separating catalyst from a gas phase connected to the lower outlet from the first dropper reactor (1) and having an outlet (106) for gas phase and an outlet for coked catalyst;
      a second substantially vertical riser reactor (2) having a lower inlet and an upper outlet;
      a second means (110) for supplying catalyst connected to the outlet for coked catalyst from the first separation vessel and to the lower inlet to the second reactor;
      a second means (202) for supplying feed located above the lower inlet into the second reactor;
      a second vessel (203) for separating used catalyst from a second gas phase connected to said upper outlet from said second reactor, said second vessel comprising a catalyst stripping chamber (212) and having an upper outlet (206) for a gas phase and a lower outlet (7) for used catalyst, said lower outlet being connected to the regenerator (301).
    13. An apparatus according to claim 12, in which the first separation chamber (105) comprises a chamber (111) for stripping catalyst in communication therewith.
    14. An apparatus according to claim 12 or claim 13, in which the second riser reactor comprises a supplemental means for supplying catalyst connected to the regenerator and disposed above the feed supply means.
    15. An apparatus according to claim 12 or claim 13, in which the second riser reactor comprises a supplemental means for supplying catalyst connected to the regenerator and disposed below the feed supply means.
    16. An apparatus according to any one of claims 12 to 15, in which means for quenching the effluents are disposed downstream of the first separation vessel.
    17. An apparatus according to any one of claims 12 to 16, comprising two catalyst regenerators, in which the second regenerator (302) is connected to the first means (309, 101) for supplying catalyst to the first dropper reactor (1) and in which the first regenerator (301) disposed below the second is connected to the second vessel (203, 211) for separation and stripping.
    EP99972244A 1998-11-13 1999-11-12 Method and device for catalytic cracking comprising reactors with descending and ascending flows Expired - Lifetime EP1131389B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    FR9814319 1998-11-13
    FR9814319A FR2785907B1 (en) 1998-11-13 1998-11-13 CATALYTIC CRACKING PROCESS AND DEVICE COMPRISING DOWN-FLOW AND UP-FLOW REACTORS
    PCT/FR1999/002801 WO2000029508A1 (en) 1998-11-13 1999-11-12 Method and device for catalytic cracking comprising reactors with descending and ascending flows

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    EP1131389A1 EP1131389A1 (en) 2001-09-12
    EP1131389B1 true EP1131389B1 (en) 2004-07-14

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    EP99972244A Expired - Lifetime EP1131389B1 (en) 1998-11-13 1999-11-12 Method and device for catalytic cracking comprising reactors with descending and ascending flows

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    US (1) US6641715B1 (en)
    EP (1) EP1131389B1 (en)
    JP (1) JP2002530467A (en)
    KR (1) KR100607922B1 (en)
    AT (1) ATE271114T1 (en)
    DE (1) DE69918710T2 (en)
    ES (1) ES2226502T3 (en)
    FR (1) FR2785907B1 (en)
    WO (1) WO2000029508A1 (en)

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    FR2811327B1 (en) * 2000-07-05 2002-10-25 Total Raffinage Distribution HYDROCARBON CRACKING PROCESS AND DEVICE IMPLEMENTING TWO SUCCESSIVE REACTIONAL CHAMBERS
    CN1205305C (en) * 2001-11-29 2005-06-08 中国石油化工股份有限公司 New-type catalytic cracking reaction-regeneration system
    FR2894849B1 (en) * 2005-12-20 2008-05-16 Inst Francais Du Petrole NEW REACTOR WITH TWO REACTIONAL ZONES FLUIDIZED WITH INTEGRATED GAS / SOLID SEPARATION SYSTEM
    CN101029248B (en) * 2006-02-28 2012-08-15 中国石油化工股份有限公司 Method for increasing light olefin yield
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    FR2909897B1 (en) * 2006-12-13 2009-06-26 Inst Francais Du Petrole NEW SOLID GAS SEPARATION SYSTEM FOR REGENERATORS OF FLUIDIZED BED CATALYTIC CRACKING UNITS
    FR2918070B1 (en) * 2007-06-27 2012-10-19 Inst Francais Du Petrole REACTIONAL ZONE COMPRISING TWO PARALLEL RISERS AND A COMMON SOLID GAS SEPARATION AREA FOR THE PRODUCTION OF PROPYLENE
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    DE69918710T2 (en) 2004-12-02
    ES2226502T3 (en) 2005-03-16
    FR2785907A1 (en) 2000-05-19
    US6641715B1 (en) 2003-11-04
    ATE271114T1 (en) 2004-07-15
    DE69918710D1 (en) 2004-08-19
    KR20010089439A (en) 2001-10-06
    FR2785907B1 (en) 2001-01-05
    EP1131389A1 (en) 2001-09-12
    WO2000029508A1 (en) 2000-05-25
    KR100607922B1 (en) 2006-08-04
    JP2002530467A (en) 2002-09-17

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