HEAVY OIL CATALYTIC CRACKING

Description

[0001] This invention is concerned with a fluidized catalytic cracking process wherein coked deactivated catalyst is subject to high temperature stripping to control the carbon level on spent catalyst. More particularly, the concept employs a high temperature stripper to control the carbon level on the spent catalyst, followed by catalyst cooling to control the temperature of the catalyst to regeneration.

[0002] The field of catalytic cracking has undergone progressive development since 1940. The trend of development of the fluid catalytic cracking process has been to all riser cracking, use of zeolite-containing catalysts and heat balanced operation.

[0003] Other major trends in fluid catalytic cracking processing have been modifications to the process to permit it to accommodate a wider range of feedstocks, in particular, feedstocks that contain more metals and sulfur than had previously been permitted in the feed to a fluid catalytic cracking unit.

[0004] Along with the development of process modifications and catalysts, which could accommodate these heavier, dirtier feeds, there has been a growing concern about the amount of sulfur contained in the feed that ends up as SO_x in the regenerator flue gas. Higher sulfur levels in the feed, combined with a more complete regeneration of the catalyst in the fluid catalytic cracking regenerator tends to increase the amount of SO_x contained in the regenerator flue gas. Some attempts have been made to minimize the amount of SO_x discharged to the atmosphere through the flue gas by providing agents to react with the SO_x in the flue gas. These agents pass along with the regenerated catalyst back to the fluid catalytic cracking reactor, and then the reducing atmosphere releases the sulfur compounds as H₂S. Suitable agents for this purpose have been described in U. S. Patent Nos. 4,071,436 and 3,834,031. Use of a cerium oxide agent for this purpose is shown in U. S. Patent No. 4,001,375.

[0005] Unfortunately, the conditions in most fluid catalytic cracking regenerators are not the best for SO_x adsorption. The high temperatures encountered in modern fluid catalytic cracking regenerators (up to 870^oC (1600^oF)) tend to discourage SO_x adsorption. One approach to overcome the problems of SO_x in flue gas is to pass catalyst from a fluid catalytic cracking reactor to a long residence time steam stripper. After the long residence time steam stripping, the catalyst passes to the regenerator, as disclosed by U.S. Patent No. 4,481,103 to Krambeck et al. However, this process preferably steam strips spent catalyst at 500^o-550^oC (932^o to 1022^oF), which is not sufficient to remove some undesirable sulfur- or hydrogen-containing components. Furthermore, catalyst passing from a fluid catalytic cracking stripper to a fluid catalytic cracking regenerator contains hydrogen-containing components, such as coke, adhering thereto. This causes hydrothermal degradation when the hydrogen reacts with oxygen in the regenerator to form water.

[0006] US-A-3 392 110 discloses a method for the catalytic conversion of hydrocarbons wherein the catalyst is separated from a fluid catalytic cracking unit; stripped; fed to a heat exchanger and mixed with regenerated catalyst prior to being fed into the regenerator. This reference does not teach heating the spent catalyst by mixing a portion thereof with regenerated catalyst and stripping the mixed catalyst with a stripping gas. Moreover, there is no disclosure in this reference relating to cooling the stripped mixture of catalysts prior to feeing the mixture to the regenerator.

[0007] U.S. Patent No. 4,336,160 to Dean et al attempts to reduce hydrothermal degradation by staged regeneration. However, the flue gas from both stages of regeneration contains SO_X which is difficult to clean.

[0008] Another need of the prior art is to provide improved means for controlling fluid catalytic cracking regeneration temperature. Improved regenerator temperature control is desirable, because regenerator temperatures above 871^oC (1600^oF) can deactivate fluid cracking catalyst. Typically, the temperature is controlled by adjusting the CO/CO₂ ratio produced in the regenerator. This control works on the principle that production of CO produces less heat than production of CO₂. However, in some cases, this control is insufficient.

[0009] It would be desirable to separate hydrogen from catalyst to eliminate hydrothermal degradation. It would be further advantageous to remove sulfur-containing compounds prior to regeneration to prevent SO_X from passing into the regenerator flue gas. Also, it would be advantageous to better control regenerator temperature.

[0010] U. S. Patent No. 4,353,812 to Lomas et al discloses cooling catalyst from a regenerator by passing it through the shell side of a heat-exchanger with a cooling medium through the tube side. The cooled catalyst is recycled to the regeneration zone. This process is disadvantageous, in that it does not control the temperature of catalyst from the reactor to the regenerator.

[0011] The prior art also includes fluid catalytic cracking processes which utilize dense or dilute phase regenerated fluid catalyst heat removal zones or heat-exchangers that are remote from, and external to, the regenerator vessel to cool hot regenerated catalyst for return to the regenerator. Examples of such processes are found in U. S. Patent Nos. 2,970,117 to Harper; 2,873,175 to Owens; 2,862,798 to McKinney; 2,596,748 to Watson et al; 2,515,156 to Jahnig et al; 2,492,948 to Perger; and 2,506,123 to Watson. The processes disclosed in these patents have the disadvantage that the regenerator operating temperature is affected with the temperature of catalyst from the stripper to the regenerator.

[0012] Accordingly, the present invention comprises a fluid catalytic cracking process and apparatus which employs a high temperature stripper, followed by cooling of the stripped catalyst to control a regenerator inlet temperature.

[0013] The present invention provides a process for controlling the fluid catalytic cracking of a feedstock containing hydrocarbons, comprising the steps of:
   passing a mixture comprising catalyst and the feedstock through a riser conversion zone under fluid catalytic cracking conditions to crack the feedstock;
   passing the mixture, having a riser exit temperature, from the riser into a fluid catalytic cracking reactor vessel;
   separating a portion of catalyst from the mixture, with the remainder of the mixture forming a reactor vessel gaseous stream;
   heating the separated catalyst portion by combining the separated catalyst portion with a portion of regenerated catalyst from a fluid catalytic cracking regenerator vessel to form combined catalyst;
   stripping the combined catalyst, by contact with a stripping gas stream, at a stripping temperature between 55°C (100°F) above the riser exit temperature and 816°C (1500°F), the regenerated catalyst portion having a temperature between 55°C or (100°F) above the stripping temperature and 871°C (1600°F) prior to heating the separated catalyst;
   cooling the stripped catalyst, prior to passing it into the regenerator vessel, to a temperature sufficient to cause the regenerator vessel to be maintained at a temperature between 55°C (100°F) above the stripping temperature and 871°C (1600°F); and
   regenerating the cooled catalyst stream in the fluid catalytic cracking regenerator vessel by contact with an oxygen-containing stream at fluid catalytic cracking regeneration conditions.

[0014] The riser exit temperature is defined as the temperature of the catalyst-hydrocarbon mixture exiting from the riser. The riser exit temperature may be at any suitable temperature. However, a riser exit temperature of 482°-593°C (900° to 1100°F) is preferred, and 538°- 566°C (1000° to 1050°F) is most preferred.

[0015] More particularly the present invention provides a process for controlling the fluid catalytic cracking of a feedstock containing hydrocarbons and sulfur-containing compounds, comprising the steps of:
   passing a mixture comprising catalyst and the feedstock through a riser conversion zone at fluid catalytic cracking conditions to crack the feedstock;
   passing the mixture, having a riser exit temperature between 538°-566°C (1000° and 1050°F), from the riser conversion zone to a closed cyclone system located within a fluid catalytic cracking reactor vessel;
   separating a portion of catalyst from the mixture in the closed cyclone system, with the remainder of the mixture forming a reactor vessel gaseous stream;heating the separated catalyst portion by combining the separated catalyst portion in the reactor vessel, with a portion of regenerated catalyst from a fluid catalytic cracking regenerator vessel to form combined catalyst;
   stripping the combined catalyst, by contact with a stripping gas stream in the reactor vessel, under stripping conditions comprising a stripping temperature between 83°C (150°F) above the riser exit temperature and 760°C (1400°F) and a residence time of a gaseous stream from 0.5 to 5 seconds, the regenerated catalyst portion having a temperature between 83°C (150°F) above the stripping temperature and 871°C (1600°F) prior to heating the separated catalyst, wherein the separated catalyst portion comprises sulfur-containing compounds and hydrocarbons derived from the feedstock, the stripping conditions are sufficient to separate 45 to 55% of the sulfur-containing compounds and 70 to 80% of hydrogen from the hydrocarbons in the separated catalyst portion of the combined catalyst to produce the gaseous stream, and the gaseous stream comprises stripping gas and molecular hydrogen, hydrocarbons and the sulfur-containing hydrocarbons separated from the separated catalyst;
   cooling the stripped catalyst stream to between 28°-83°C (50° and 150°F) below the stripping temperature by indirect heat-exchange with a heat-exchange medium in a beat-exchanger located outside the reactor vessel, causing the regenerator vessel to be maintained at a temperature between 83°C (150°F) above the stripping temperature and 871°C (1600°F), thereby maintaining said regenerator vessel temperature independently of the stripping step temperature; and
   regenerating the cooled catalyst stream in the fluid catalytic cracking regenerator vessel, by contact with an oxygen-containing stream under fluid catalytic cracking regeneration conditions.

[0016] In its apparatus respects, the present invention provides an apparatus for controlling the fluid catalytic cracking of a feedstock comprising hydrocarbons, comprising:
   means defining a riser conversion zone through which a mixture comprising catalyst and the feedstock passes at fluid catalytic cracking conditions to crack the feedstock;
   a fluid catalytic cracking reactor vessel;
   means for passing the mixture from the riser into the fluid catalytic cracking reactor vessel, the mixture having a riser exit temperature as it passes into the reactor vessel;
   means for separating a portion of catalyst from the mixture, with the remainder of the mixture forming a reactor vessel gaseous stream;
   means for heating the separated catalyst portion, comprising means for combining the separated catalyst portion with a portion of regenerated catalyst to form combined catalyst;
   means for stripping the combined catalyst by contact with a stripping gas stream to form a stripped catalyst stream;
   a fluid catalytic cracking regenerator vessel for producing the portion of regenerated catalyst; and
   a heat-exchanger for cooling the stripped catalyst stream, the heat-exchanger being located outside the reactor vessel, the fluid catalytic cracking regenerator vessel thereby regenerating the cooled catalyst stream by contact with an oxygen-containing stream at fluid catalytic cracking regenerator conditions.

[0017] In its more particular apparatus aspects, the present invention provides an apparatus for controlling the fluid catalytic cracking of a feedstock comprising hydrocarbons and sulfur-containing compounds, comprising:
   means defining a riser conversion zone through which a mixture comprising catalyst and the feedstock passes at fluid catalytic cracking conditions to crack the feedstock;
   a fluid catalytic cracking reactor vessel;
   means for passing the mixture from the riser conversion zone to a closed cyclone system located within the fluid catalytic cracking reactor vessel, the mixture having a riser exit temperature between 538°-566°C (1000° and 1050°F) as it passes from the riser to the closed cyclone system, the closed cyclone system including means for separating a portion of catalyst from the mixture and forming a reactor vessel gaseous stream from the remainder of the mixture;
   means for heating the separated portion of catalyst, comprising means for combining a portion of regenerated catalyst with the separated catalyst portion to form a combined catalyst in the reactor vessel;
   means for stripping the combined catalyst by contact with a stripping gas in the reactor vessel, thereby maintaining the combined catalyst in the means for stripping at a stripping temperature between 83°C (150°F) above the temperature of the mixture exiting the riser and 760°C (1400°F) and a residence time of gas in the means for stripping from 0.5 to 5 seconds, the separated catalyst portion comprising hydrocarbons and sulfur-containing compounds derived from the feedstock, the means for stripping thereby separating 45 to 55% of the sulfur-containing compounds and 70 to 80% of hydrogen from the hydrocarbons in the separated catalyst portion;
   a stripped catalyst effluent conduit, attached to the reactor vessel for passing the stripped catalyst stream therethrough;
   a fluid catalytic cracking regenerator vessel for producing the portion of regenerated catalyst at a temperature between 83°C (150°F) above the stripping temperature and 871°C (1600°F); and
   an indirect heat-exchanger attached to the reactor effluent conduit, whereby the indirect heat-exchanger is sufficiently sized for cooling the stripped catalyst stream to a temperature between 28°-83°C (50° and 150°F) below the stripping temperature, thereby causing the catalyst in the regenerator vessel to be maintained at a temperature between 83°C (150°F) above the stripping temperature and 871°C (1600°F), causing the temperature of the catalyst in the regenerator vessel to be maintained independently of the stripping temperature, the regenerator vessel regenerating the cooled catalyst stream by contacting it with an oxygen-containing stream under fluid catalytic cracking regeneration conditions.

[0018] The present invention strips catalyst at a temperature higher than the riser exit temperature to separate hydrogen, as molecular hydrogen or hydrocarbons from the coke which adheres to catalyst, to eliminate hydrothermal degradation, which typically occurs when hydrogen reacts with oxygen in a fluid catalytic cracking regenerator to form water. The high temperature stripper (hot stripper) also removes sulfur from coked catalyst as hydrogen sulfide and mercaptans, which are easy to scrub. In contrast, removing sulfur from coked catalyst in a regenerator produces SO_X, which passes into the regenerator flue gas and is more difficult to scrub. Furthermore, the high temperature stripper removes additional valuable hydrocarbon products to prevent burning these hydrocarbons in the regenerator. An additional advantage of the high temperature stripper is that it quickly separates hydrocarbons from catalyst. If catalyst contacts hydrocarbons for too long a time at a temperature greater than or equal to 538°C (1000°F), then diolefins are produced which are undesirable for downstream processing, such as alkylation. However, the present invention allows a precisely controlled, short contact time at 538°C (1000°F) or greater to produce premium, unleaded gasoline with high selectivity.

[0019] The heat-exchanger (catalyst cooler) controls regenerator temperature. This allows the hot stripper to run at a desired temperature to control sulfur and hydrogen without interfering with a desired regenerator temperature. It is desired to run the regenerator at least 55°C (100°F) hotter than the hot stripper. However, the regenerator temperature should be kept below 871°C (1600°F) to prevent deactivation of the catalyst.

[0020] The drawing is a schematic representation of a high temperature stripper and catalyst cooler of the present invention.

[0021] The figure illustrates a fluid catalytic cracking system of the present invention. In the figure, a hydrocarbon feed passes from a hydrocarbon feeder 1 to the lower end of a riser conversion zone 4. Regenerated catalyst from a standpipe 102, having a control valve 104, is combined with the hydrocarbon feed in the riser 4, such that a hydrocarbon-catalyst mixture rises in an ascending dispersed stream and passes through a riser effluent conduit 6 into a first reactor cyclone 8. The riser exit temperature, defined as the temperature at which the mixture passes from the riser 4 to conduit 6, ranges between 482° and 593°C (900° and 1100°F), and preferably between 538° and 566°C (1000° and 1050°F). The riser exit temperature is controlled by monitoring and adjusting the rates and temperatures of hydrocarbons and regenerated catalyst into the riser 4. Riser effluent conduit 6 is attached at one end to the riser 4 and at its other end to the cyclone 8.

[0022] The first reactor cyclone 8 separates a portion of catalyst from the catalyst-hydrocarbon mixture and passes this catalyst down a first reactor cyclone dipleg 12 to a stripping zone 30 located therebelow. The remaining gas and catalyst pass from the first reactor cyclone 8 through a gas effluent conduit 10. The conduit 10 is provided with a connector 24 to allow for thermal expansion. The catalyst passes through the conduit 10, then through a second reactor cyclone inlet conduit 22, and into a second reactor cyclone 14. The second cyclone 14 separates the stream to form a catalyst stream, which passes through a second reactor cyclone dipleg 18 to the stripping zone 30 located therebelow, and an overhead stream

[0023] The second cyclone overhead stream, which contains the remaining gas and catalyst, passes through a second cyclone gaseous effluent conduit 16 to a reactor overhead port 20. Gases from the atmosphere of the reactor vessel 2 may pass through a reactor overhead conduit 22 into the reactor overhead port 20. The gases which exit the reactor 2 through the second cyclone gaseous effluent conduit 16 and the reactor overhead conduit 22 are combined and exit through the reactor overhead port 20. It will be apparent to those skilled in the art that although only one series connection of cyclones 8, 14 is shown in the embodiment, more than one series connection and/or more or less than two consecutive cyclones in series connection could be employed.

[0024] The mixture of catalyst and hydrocarbons passes through the first reactor cyclone overhead conduit 10 and the second reactor cyclone inlet conduit 22 without entering the reactor vessel 2 atmosphere. However, the connector 24 may provide an annular port to admit stripping gas from the reactor vessel 2 into the conduit 10 to aid in separating catalyst from hydrocarbons adhering thereto. The closed cyclone system and annular port is described more fully in U. S. Patent No. 4,502,947 to Haddad et al.

[0025] The separated catalyst from cyclones 8, 14 pass through respective diplegs 12, 18 and are discharged therefrom after a suitable pressure is generated within the diplegs by the buildup of the catalyst. The catalyst falls from the diplegs into a bed of catalyst 31 located in the stripping zone 30. The first dipleg 12 is sealed by being extended into the catalyst bed 31. The second dipleg 18 is sealed by a trickle valve 19. The separated catalyst is contacted and combined with hot regenerated catalyst from the regenerator 80 in the stripping zone 30. The regenerated catalyst has a temperature in the range between 55°C (100°F) above that of the stripping zone 30 and 871°C (1600°F) to heat the separated catalyst in bed 31. The regenerated catalyst passes from the regenerator 80 to the reactor vessel 2 through a transfer line 106 attached at one end to the regenerator vessel 80 and at another end to the reactor vessel 2. The transfer line 106 is provided with a slide valve 108. Combining the separated catalyst with the regenerated catalyst promotes the stripping at a temperature in the range between 55°C (100°F) above the riser exit temperature and 816°C (1500°F). Preferably, the catalyst stripping zone operates at a temperature between 83°C (150°F) above the riser exit temperature and 760°C (1400°F).

[0026] The catalyst 31 in the stripping zone 30 is contacted at high temperature, discussed above, with a stripping gas, such as steam, flowing countercurrently to the direction of flow of the catalyst. The stripping gas is introduced into the lower portion of the stripping zone 30 by one or more conduits 34 attached to a stripping gas header 36. The catalyst residence time in the stripping zone 30 ranges from 2.5 to 7 minutes. The vapor residence time in the catalyst stripping zone 30 ranges from 0.5 to 30 seconds, and preferably 0.5 to 5 seconds. The stripping zone 30 removes coke, sulfur and hydrogen from the separated catalyst which has been combined with the regenerated catalyst. The sulfur is removed as hydrogen sulfide and mercaptans. The hydrogen is removed as molecular hydrogen, hydrocarbons, and hydrogen sulfide. Most preferably, the stripping zone 30 is maintained at temperatures between 83°C (150°F) above the riser exit temperature, which are sufficient to reduce coke load to the regenerator by at least 50%, remove 70-80% of the hydrogen as molecular hydrogen, light hydrocarbons and other hydrogen-containing compounds, and remove 45 to 55% of the sulfur as hydrogen sulfide and mercaptans, as well as a portion of nitrogen as ammonia and cyanides.

[0027] The catalyst stripping zone 30 may also be provided with trays (baffles) 32. The trays may be disc- and doughnut-shaped and may be perforated or unperforated.

[0028] Stripped catalyst passes through a stripped catalyst effluent conduit 38 to a catalyst cooler 40. The catalyst cooler 40 is a heat-exchanger which cools the stripped catalyst from the reactor vessel 2 to a temperature sufficient to maintain the regenerator vessel 80 at a temperature between 55°C (100°F) above the temperature of the stripping zone 30 and 871°C (1600°F). Preferably, the catalyst cooler 40 cools the stripped catalyst stream to a temperature sufficient to control the regenerator vessel 80 at a temperature to between 83°C (150°F) above the temperature of the stripping zone 30 and 871°C (1600°F). Most preferably, the stripped catalyst stream is cooled between 28° and 83°C (50° and 150°F) below the stripping zone temperature, so long as the cooled catalyst temperature is at least 593°C (1100°F).

[0029] The catalyst cooler 40 is preferably an indirect heat-exchanger located outside the reactor vessel 2. A heat-exchange medium, such as liquid water (boiler feed water), passes through a conduit 50, provided with a valve 54, into a set of tubes 48 within the catalyst cooler 40. The catalyst passes through the shell side 46 of the catalyst cooler 40. The catalyst cooler 40 is attached to an effluent conduit 42 provided with a slide valve 44. The cooled catalyst passes through the conduit 42 into a regenerator inlet conduit 60.

[0030] In the regenerator riser 60, air and cooled catalyst combine and pass upwardly through an air catalyst disperser 74 into a fast fluid bed 62. The fast fluid bed 62 is part of the regenerator vessel 80. In the fast fluid bed 62, combustible materials, such as coke which adheres to the cooled catalyst, are burned off the catalyst by contact with lift air. Air passes through an air supply line 66 through a control valve 68 and an air transfer line 68 to the regenerator inlet conduit 60. Optionally, if the temperature of the cooled catalyst from the conduit 42 is less than 593°C (1100°F), a portion of hot regenerated catalyst from the standpipe 102 passes through a conduit 101, provided with a control valve 103, into the fast fluid bed 62. The fast fluid bed 62 contains a relatively dense catalyst bed 76. The air fluidizes the catalyst in bed 76, and subsequently transports the catalyst continuously as a dilute phase through the regenerator riser 83. The dilute phase passes upwardly through the riser 83, through a radial arm 84 attached to the riser 83, and then passes downwardly to a second relatively dense bed of catalyst 82 located within the regenerator vessel 80.

[0031] The major portion of catalyst passes downwardly through the radial arms 84, while the gases and remaining catalyst pass into the atmosphere of the regenerator vessel 80. The gases and remaining catalyst then pass through an inlet conduit 89 and into the first regenerator cyclone 86. The first cyclone 86 separates a portion of catalyst and passes it through a first dipleg 90, while remaining catalyst and gases pass through an overhead conduit 88 into a second regenerator cyclone 92. The second cyclone 92 separates a portion of catalyst and passes the separated portion through a second dipleg 96 having a trickle valve 97, with the remaining gas and catalyst passing through a second overhead conduit 94 into a regenerator vessel plenum chamber 98. A flue gas stream 110 exits from the regenerator plenum chamber 98 through a regenerator flue gas conduit 100.

[0032] The regenerated catalyst settles to form the bed 82, which is dense compared to the dilute catalyst passing through the riser 83. The regenerated catalyst bed 82 is at a substantially higher temperature than the stripped catalyst from the stripping zone 30, due to the coke burning which occurs in the regenerator 80. The catalyst in bed 82 is at least 55°C (100°F) hotter than the temperature of the stripping zone 30, preferably at least 83°C (150°F) hotter than the temperature of the stripping zone 30. The regenerator temperature is, at most, 871°C (1600°F) to prevent deactivating the catalyst. Coke burning occurs in the regenerator inlet conduit 60, as well as the fast fluid bed 62 and riser 83.

[0033] Optionally, air may also be passed from the air supply line 64 to an air transfer line 70, provided with a control valve 72, to an air header 78 located in the regenerator 80. The regenerated catalyst then passes from the relatively dense bed 82 through the conduit 106 to the stripping zone 30 to provide heated catalyst for the stripping zone 30.

[0034] Any conventional fluid catalytic cracking catalyst can be used in the present invention. Use of zeolite catalysts in an amorphous base is preferred. Many suitable catalysts are discussed in U. S. Patent No. 3,926,778 to Owen et al.

[0035] One example of a process which can be conducted in accordance with the present invention begins with a 343° to 593°C (650° to 1100°F) boiling point hydrocarbon feedstock which passes into a riser conversion zone 4, where it combines with hot regenerated catalyst at a temperature of about 815°C (1500°F) from a catalyst standpipe 102 to form a catalyst-hydrocarbon mixture. The catalyst-hydrocarbon mixture passes upwardly through the riser conversion zone 4 and into a riser effluent conduit 6 at a riser exit temperature of about 538°C (1000°F). The catalyst passes from the conduit 6 into the first reactor cyclone 8, where a portion of catalyst is separated from the mixture and drops through a dipleg 12 to a bed of catalyst 31 contained within a stripping zone 30 therebelow. The stripping zone 30 operates at about 704°C (1300°F). The remainder of the mixture passes upwardly through the first overhead conduit 10 into a second reactor cyclone 14. The second cyclone 14 separates a portion of catalyst from the first cyclone overhead stream and passes the separated catalyst down the second dipleg 18. The remaining solids and gases pass upwardly as a second cyclone overhead stream through conduit 16 into the reactor vessel overhead port 20.

[0036] In the stripping zone 30, the catalyst from diplegs 12, 18 combines with catalyst from regenerator 80, which passes through a conduit 106 and is stripped by contact with steam from a steam header 36. The regenerated catalyst from the conduit 106 is at a temperature of about 815°C (1500°F) and provides heat to maintain the stripping zone 30 at about 704°C (1300°F). The stripped catalyst passes through a conduit 38 into a catalyst cooler 40 at a temperature of about 704°C (1300°F). The catalyst cooler 40 cools the 704°C (1300°F) catalyst to about 621°C (1150°F). The cooling occurs by indirect heat-exchange of the hot stripped catalyst with boiler feed water, which passes through a conduit 50 to form steam which exits through a conduit 52.

[0037] The cooled catalyst, at a temperature of about 621°C (1150°F), combines with lift air from a conduit 66 in a regenerator inlet conduit 60 to form an air-catalyst mixture. The mixture passes upwardly through the conduit 60 into fast fluid bed 76. The catalyst continues upwardly from fast fluid bed 76 through the regenerator riser 83 and into a regenerator vessel 80. The catalyst is then separated from gases by the radial arm 84, as well as cyclones 86 and 92, and passes downwardly through the regenerator to form a relatively dense bed 82. The coke adhering to the stripped catalyst burns in the conduit 60, the fast fluid bed 62, the riser 83, and the regenerator vessel 80. Due to the coke burning, the catalyst in bed 82 is heated to a temperature of about 815°C (1500°F). Catalyst bed 82 then supplies catalyst for the standpipe 102, which combines with the hydrocarbon feedstock. Bed 82 also provides catalyst for conduit 106 which passes to the stripping zone 30. Gaseous effluents pass through a first cyclone 86 and second cyclone 92 and leave the regenerator 80 as a flue gas stream 110 through a flue gas conduit 100.

[0038] Operating the stripping zone as a high temperature (hot) stripper, at a temperature between 55°C (100°F) above a riser exit temperature and 816°C (1500°F), has the advantage that it separates hydrogen, as molecular hydrogen as well as hydrocarbons, from catalyst. Hydrogen removal eliminates hydrothermal degradation, which typically occurs when hydrogen reacts with oxygen in a fluid catalytic cracking regenerator to form water. The hot stripper also removes sulfur from coked catalyst as hydrogen sulfide and mercaptans, which are easy to scrub. By removing sulfur from coked catalyst in the hot stripper, the hot stripper prevents formation of SO_X in the regenerator. It is more difficult to remove SO_X from regenerator flue gas than to remove hydrogen sulfide and mercaptans from a hot stripper effluent. The hot stripper enhances removal of hydrocarbons from spent catalyst, and thus prevents burning of valuable hydrocarbons in the regenerator. Furthermore, the hot stripper quickly separates hydrocarbons from catalyst to avoid overcracking.

[0039] Preferably the hot stripper is maintained at a temperature between 83°C (150°F) above a riser exit temperature and 760°C (1400°F) to reduce coke load to the regenerator by at least 50%, and strip away 70 to 80% of the hydrogen as molecular hydrogen, light hydrocarbons and other hydrogen-containing compounds. The hot stripper is also maintained within the desired temperature conditions to remove 45 to 55% of the sulfur as hydrogen sulfide and mercaptans, as well as a portion of nitrogen as ammonia and cyanides.

[0040] This concept advances the development of a heavy oil (residual oil) catalytic cracker and high temperature cracking unit for conventional gas oils. The process combines the control of catalyst deactivation with controlled catalyst carbon-contamination level and control of temperature levels in the stripper and regenerator.

[0041] The hot stripper temperature controls the amount of carbon removed from the catalyst in the hot stripper. Accordingly, the hot stripper controls the amount of carbon (and hydrogen, sulfur) remaining on the catalyst to the regenerator. This residual carbon level controls the temperature rise between the reactor stripper and the regenerator. The hot stripper also controls the hydrogen content of the spent catalyst sent to the regenerator as a function of residual carbon. Thus, the hot stripper controls the temperature and amount of hydrothermal deactivation of catalyst in the regenerator. This concept may be practiced in a multi-stage, multi-temperature stripper or a single stage stripper.

[0042] Employing a hot stripper, to remove carbon on the catalyst, rather than a regeneration stage reduces air pollution, and allows all of the carbon made in the reaction to be burned to CO₂, if desired.

[0043] The stripped catalyst is cooled (as a function of its carbon level) to a desired regenerator inlet temperature to control the degree of regeneration desired, in combination with the other variables of CO/CO₂ ratio desired, the amount of carbon burn-off desired, the catalyst recirculation rate from the regenerator to the hot stripper, and the degree of desulfurization/denitrification/decarbonization desired in the hot stripper. Increasing CO/CO₂ ratio decreases the heat generated in the regenerator, and accordingly decreases the regenerator temperature. Burning the coke, adhering to the catalyst in the regenerator, to CO removes the coke, as would burning coke to CO₂, but burning to CO produces less heat than burning to CO₂. The amount of carbon (coke) burn-off affects regenerator temperature, because greater carbon burn-off generates greater heat. The catalyst recirculation rate from the regenerator to the hot stripper affects regenerator temperature, because increasing the amount of hot catalyst from the regenerator to the hot stripper increases hot stripper temperature. Accordingly, the increased hot stripper temperature removes increased amounts of coke so less coke need burn in the regenerator; thus, regenerator temperature can decrease.

[0044] The catalyst cooler controls regenerator temperature, thereby allowing the hot stripper to be run at temperatures between 55°C (100°F) above a riser exit temperature to 816°C (1500°F), which facilitate controlling sulfur and hydrogen, while allowing the regenerator to be run independently at temperatures at least 100°F hotter than the stripper, while preventing regenerator temperatures greater than 871°C (1600°F) which deactivate catalyst.

[0045] Use of the catalyst cooler on catalyst exiting the stripper also allows circulation of catalyst to the regenerator riser to increase catalyst density in the regenerator riser, while controlling the regenerator temperature. This reduces catalyst deactivation and provides additional control.

[0046] While specific embodiments of the method and apparatus aspects of the invention have been shown and described, it should be apparent that the many modifications can be made thereto. Accordingly, the invention is not limited by the foregoing description, but is only limited by the scope of the claims appended thereto.

Claims

1. A process for controlling the fluid catalytic cracking of a feedstock containing hydrocarbons, comprising the steps of:
   passing a mixture comprising catalyst and the feedstock through a riser conversion zone under fluid catalytic cracking conditions to crack the feedstock;
   passing the mixture, having a riser exit temperature, from the riser into a fluid catalytic cracking reactor vessel;
   separating a portion of catalyst from the mixture, with the remainder of the mixture forming a reactor vessel gaseous stream;
   heating the separated catalyst portion by a heat step consisting essentially of combining the separated catalyst portion with a portion of regenerated catalyst from a fluid catalytic cracking regenerator vessel to form combined catalyst;
   stripping the combined catalyst, by contact with a stripping gas stream, at a stripping temperature between 55°C above the riser exit temperature and 815°C, the regenerated catalyst portion having a temperature between 55°C above the stripping temperature and 871°C prior to heating the separated catalyst to produce a stripped catalyst;
   cooling the stripped catalyst, prior to passing it into the regenerator vessel, to a temperature sufficient to cause the regenerator vessel to be maintained at a temperature between 55°C above the stripping temperature and 871°C wherein the cooling step comprises passing the stripped catalyst stream to a heat exchanger located outside the reactor vessel; and
   regenerating the cooled catalyst stream in the fluid catalytic cracking regenerator vessel by contact with an oxygen-containing stream at fluid catalytic cracking regeneration conditions.

2. The process of claim 1, wherein the stripped catalyst stream is indirectly heat-exchanged with a heat-exchange medium in the heat exchanger.

3. The process of claim 1 or 2, wherein the riser exit temperature ranges between 482°C and 593°C, and the heat-exchanger cools the stripped catalyst stream to cause the catalyst in the regenerator vessel to be maintained at a temperature between 83°C above the stripping step temperature and 871°C.

4. The process of claim 1, 2 and 3 wherein the heating step and the stripping step occur within the reactor vessel and the stripping step occurs at a stripping temperature between 83°C above the riser exit temperature and 760°C and a residence time for the gaseous stream from 0.5 to 5 seconds.

5. The process of any one of the preceding claims, wherein the separating step comprises separating the mixture from the riser conversion zone in a closed cyclone system in communication with the riser conversion zone.

6. The process of any one of the preceding claims, wherein the riser exit temperature ranges from 538°C to 565°C and the stripped catalyst stream is cooled in the heat-changer to between 28°C and 83°C below the stripping temperature, the heat-exchanger thereby causing the regenerator vessel temperature to be maintained independently of the stripping temperature.

7. The process of any one the preceding claims, wherein the separated catalyst portion of the combined catalyst contains sulfur-containing compounds and hydrogen- containing compounds derived from the feedstock, and the stripping step removes 45 to 55% of the sulfur-containing compounds and 70 to 80% of the hydrogen-containing compounds in the separated catalyst portion.

8. The process of any one of the preceding claims, wherein the combined catalyst passes countercurrently to the stripping gas during the stripping step.

9. An apparatus for carrying out the process of any one of claims 1-8 comprising:
   means defining a riser conversion zone through which a mixture comprising catalyst and the feedstock passes at fluid catalytic cracking conditions to crack the feedstock;
   a fluid catalytic cracking reactor vessel;
   means for passing the mixture from the riser into the fluid catalytic cracking reactor vessel, the mixture having a riser exit temperature as it passes into the reactor vessel;
   means for separating a portion of catalyst from the mixture, with the remainder of the mixture forming a reactor vessel gaseous stream;
   means for heating the separated catalyst portion, by a heating step consisting essentially of combining the separated catalyst portion with a portion of regenerated catalyst to form combined catalyst;
   means for stripping the combined catalyst by contact with a stripping gas stream to form a stripped catalyst stream;
   a fluid catalytic cracking reactor vessel for producing the portion of regenerated catalyst; and
   a heat-exchanger for cooling the stripped catalyst stream, the catalyst cooler being located outside the reactor vessel, the fluid catalytic cracking regenerator vessel thereby regenerating the cooled catalyst stream by contact with an oxygen-containing stream at fluid catalytic cracking regenerator conditions;
   a stripped catalyst effluent conduit, attached to the means for stripping catalyst stream from the means for stripping to the heat-exchanger.

10. The apparatus of claim 9, wherein the heat-exchanger is upstream of the regenerator vessel.

11. The apparatus of claim 10, wherein the catalyst cooler is an indirect heat-exchanger for cooling the stripped catalyst stream to a temperature sufficient to cause the regenerator vessel to be maintained at a temperature between 55°C above the stripping temperature and 871°C, thereby producing the regenerated catalyst portion having a temperature between 55° C above the stripping temperature and 871°C.

12. The apparatus of claim 11, wherein the means for separating the mixture from the riser conversion zone comprises a closed cyclone system in communication with the riser conversion zone.

13. The apparatus of claim 12, wherein the means for stripping comprises means for passing the combined catalyst countercurrently to the stripping gas.

Ansprüche

1. Verfahren zur Regelung des katalytischen Wirbelschichtcrackens eines Ausgangsmaterials, das Kohlenwasserstoffe enthält, welches die Schritte umfaßt:
Leiten einer Mischung, die Katalysator und das Ausgangsmaterial umfaßt, durch eine Riser-Umwandlungszone bei Bedingungen für das katalytische Wirbelschichtcracken, um das Ausgangsmaterial zu cracken;
Leiten der Mischung mit der Auslaßtemperatur des Risers aus dem Riser in das Reaktorgefäß zum katalytischen Wirbelschichtcracken;
Abtrennung eines Teils des Katalysators von der Mischung, wobei der Rest der Mischung den gasförmigen Strom des Reaktorgefäßes bildet;
Erwärmen des abgetrennten Katalysatoranteils durch einen Erwärmungsschritt, der im wesentlichen aus der Kombination des abgetrennten Katalysatoranteils mit einem Anteil des regenerierten Katalysators vom Regeneratorgefäß vom katalytischen Wirbelschichtcracken besteht, um kombinierten Katalysator zu bilden;
Strippen dieses kombinierten Katalysators durch Kontakt mit einem Strippinggasstrom bei einer Strippingtemperatur Zwischen 55°C oberhalb der Auslaßtemperatur des Risers und 815°C, wobei der regenerierten Katalysatoranteil eine Temperatur zwischen 55°C oberhalb der Strippingtemperatur und 871°C hat, ehe der abgetrennte Katalysator erwärmt wird, um abgetrennten Katalysator zu erzeugen;
Abkühlen des abgetrennten Katalysators vor dem Einleiten in das Regeneratorgefäß auf eine ausreichende Temperatur, damit das Regeneratorgefäß bei einer Temperatur zwischen 55°C oberhalb der Strippingtemperatur und 871°C gehalten wird, wobei der Abkühlungsschritt das Leiten des abgetrennten Katalysatorstroms zu einem Wärmeaustauscher umfaßt, der außerhalb des Reaktorgefäßes angeordnet ist; und
Regenerierung des abgekühlten Katalysatorstroms im Regeneratorgefäß vom katalytischen Wirbelschichtcracken durch Kontakt mit einem sauerstoffhaltigen Strom bei Regenerierungsbedingungen für das katalytische Wirbelschichtcracken.

2. Verfahren nach Anspruch 1, worin der abgetrennte Katalysatorstrom einem indirekten Wärmeaustausch mit einem Wärmeaustauschmedium in einem Wärmeaustauscher unterzogen wird.

3. Verfahren nach Anspruch 1 oder 2, worin die Auslaßtemperatur des Risers zwischen 482°C und 593°C liegt und der Wärmeaustauscher den abgetrennten Katalysatorstrom abkühlt, damit der Katalysator im Regeneratorgefäß bei einer Temperatur zwischen 83°C über der Temperatur des Stripping-Schritts und 871°C gehalten wird.

4. Verfahren nach Anspruch 1, 2 und 3, worin der Erwärmungsschritt und der Stripping-Schritt im Reaktorgefäß erfolgen und der Stripping-Schritt bei einer Strippingtemperatur zwischen 83°C über der Auslaßtemperatur des Risers und 760°C und bei einer Verweilzeit für den gasförmigen Strom von 0,5 bis 5 Sekunden erfolgt.

5. Verfahren nach einem der vorstehenden Ansprüche, worin der Trennungsschritt das Abtrennen der Mischung aus der Riser-Umwandlungszone in einem geschlossenen Zyklonsystem umfaßt, das mit der Riser-Umwandlungszone in Verbindung steht.

6. Verfahren nach einem der vorstehenden Ansprüche, worin die Auslaßtemperatur des Riser im Bereich von 538°C bis 565°C liegt und der abgetrennte Katalysatorstrom im Wärmeaustauscher auf 28°C bis 93°C unterhalb der Strippingtemperatur abgekühlt wird, wodurch der Wärmeaustauscher die Aufrechterhaltung der Temperatur des Regeneratorgefäßes unabhängig von der Strippingtemperatur bewirkt.

7. Verfahren nach einem der vorstehenden Ansprüche, worin der abgetrennte Katalysatoranteil des kombinierten Katalysators schwefelhaltige Verbindungen und wasserstoffhaltige Verbindungen enthält, die vom Ausgangsmaterial abgeleitet sind, und der Stripping-Schritt 45 bis 55% der schwefelhaltigen Verbindungen und 70 bis 80% der wasserstoffhaltigen Verbindungen im abgetrennten Katalysatoranteil entfernt.

8. Verfahren nach einem der vorstehenden Ansprüche, worin der kombinierte Katalysator beim Stripping-Schritt entgegengesetzt zum Strippinggas strömt.

9. Vorrichtung zur Durchführung des Verfahrens nach einem der Ansprüche 1 bis 8, welche umfaßt:
eine Einrichtung, die eine Riser-Umwandlungszone definiert, durch die die Mischung, die Katalysator und Ausgangsmaterial umfaßt, bei Bedingungen des katalytischen Wirbelschichtcrackens strömt, um das Ausgangsmaterial zu cracken;
ein Reaktorgefäß zum katalytischen Wirbelschichtcracken;
eine Einrichtung zum Leiten der Mischung aus dem Riser in das Reaktorgefäß zum katalytischen Wirbelschichtcracken, wobei diese Mischung, wenn sie in das Reaktorgefäß strömt, die Auslaßtemperatur des Risers aufweist;
eine Einrichtung zur Abtrennung eines Anteils des Katalysators von der Mischung, wobei der Rest der Mischung den gasförmigen Strom des Reaktorgefäßes bildet;
eine Einrichtung zum Erwärmen des abgetrennten Katalysatoranteils, durch einen Erwärmungsschritt, der imm wesentlichen aus der Kombination des abgetrennten Katalysatoranteils mit einem Anteil des regenerierten Katalysators besteht, um kombinierten Katalysator zu bilden;
eine Einrichtung zum Strippen des kombinierten Katalysators durch Kontakt mit einem Strippinggasstrom, um einen abgetrennten Katalysatorstrom zu bilden;
ein Regeneratorgefäß des katalytischen Wirbelschichtcrackens zur Erzeugung des Anteils des regenerierten Katalysators; und
einen Wärmeaustauscher zur Abkühlung des abgetrennten Katalysatorstroms, wobei dieser Katalysator-Kühler außerhalb des Reaktorgefäßes angeordnet ist, wodurch das Regeneratorgefäß des katalytischen Wirbelschichtcrackens den abgekühlten Katalysatorstrom durch Kontakt mit einem sauerstoffhaltigen Strom bei Regeneratorbedingungen des katalytischen Wirbelschichtcrackens regeneriert;
eine Abflußleitung für abgetrennten Katalysator, die an die Einrichtung zum Strippen des Katalysatorstroms angebracht ist, von der Einrichtung zum Strippen zum Wärmeaustauscher.

10. Vorrichtung nach Anspruch 9, worin der Wärmeaustauscher stromaufwärts des Regeneratorgefäßes ist.

11. Vorrichtung nach Anspruch 10, worin der Katalysator-Kühler ein indirekter Wärmeaustauscher ist, um den abgetrennten Katalysatorstrom auf eine ausreichende Temperatur abzukühlen, damit das Regeneratorgefäß bei einer Temperatur zwischen 55°C über der Strippingtemperatur und 871°C gehalten wird, wodurch der regenerierte Katalysatoranteil mit einer Temperatur zwischen 55°C über der Strippingtemperatur und 871°C erzeugt wird.

12. Vorrichtung nach Anspruch 11, worin die Einrichtung zur Abtrennung der Mischung aus der Riser-Umwandlungszone ein geschlossenes Zyklonsystem umfaßt, das mit der Riser-Umwandlungszone in Verbindung steht.

13. Vorrichtung nach Anspruch 12, worin die Einrichtung zum Strippen eine Einrichtung umfaßt, um den kombinierten Katalysator im Gegenstrom zum Strippinggas zu leiten.

Revendications

1. Procédé pour contrôler le craquage catalytique fluide d'une charge d'alimentation contenant des hydrocarbures, comprenant les étapes suivantes:

- le passage d'un mélange comprenant le catalyseur et la charge d'alimentation, à travers une zone de conversion dans un réacteur ascendant, dans des conditions de craquage catalytique fluide, pour craquer la charge d'alimentation;

- le passage du mélange, ayant la température de sortie du réacteur ascendant, de ce réacteur ascendant vers un réacteur de craquage catalytique fluide;

- la séparation d'une partie du catalyseur provenant du mélange, tandis que le reste du mélange forme un courant gazeux dans le réacteur;

- le chauffage de la partie de catalyseur séparé par combinaison de la partie de catalyseur séparé avec une partie du catalyseur régénéré provenant d'un régénérateur de craquage catalytique fluide pour former un catalyseur combiné;

- l'extraction par entraînement du catalyseur combiné, par contact avec un courant gazeux d'entraînement, à une température d'entraînement comprise entre 55°C (100°F) au-dessus de la température de sortie du réacteur ascendant et 816°C (150°F), la partie de catalyseur régénéré ayant une température comprise entre 55°C (100°F) au-dessus de la température d'entraînement et 871°C (1600°F), avant de chauffer le catalyseur séparé, pour produire un catalyseur ayant subi une extraction par entraînement;

- le refroidissement du catalyseur ayant subi une extraction par entraînement, avant son passage dans le régénérateur, à une température suffisante pour provoquer le maintien de la température du régénérateur entre 55°C (100°F) au-dessus de la température d'entraînement et 871°C (1600°F), dans lequel l'étape de refroidissement comprend le passage du courant de catalyseur ayant subi une extraction par entraînement dans un échangeur de chaleur situé à l'extérieur du réacteur; et

- la régénération du courant de catalyseur refroidi dans le régénérateur de craquage catalytique fluide par contact avec un courant contenant de l'oxygène dans des conditions de régénération de craquage catalytique fluide.

2. Procédé selon la revendication 1, caractérisé en ce que le courant de catalyseur ayant subi une extraction par entraînement est soumis à un échange de chaleur indirect avec un milieu d'échange de chaleur dans l'échangeur de chaleur.

3. Procédé selon les revendications 1 ou 2, caractérisé en ce que la température de sortie du réacteur ascendant est comprise entre 482 et 593°C et l'échangeur de chaleur refroidit le courant de catalyseur ayant subi une extraction par entraînement pour provoquer le maintien de la température du catalyseur dans le régénérateur entre 83°C au-dessus de la température de l'étape d'extraction par entraînement et 871°C.

4. Procédé selon les revendications 1, 2 ou 3, caractérisé en ce que l'étape de chauffage et l'étape d'extraction par entraînement ont lieu dans le réacteur et l'étape d'extraction par entraînement a lieu à une température d'entraînement comprise entre 83°C au-dessus de la température de sortie du réacteur ascendant et 760°C et le temps de séjour du courant gazeux compris entre 0,5 et 5 secondes.

5. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que l'étape de séparation comprend la séparation du mélange provenant de la zone de conversion du réacteur ascendant dans un système de cyclones clos connecté à la zone de conversion du réacteur ascendant.

6. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que la température de sortie du réacteur ascendant est comprise entre 538 et 565°C et le courant de catalyseur ayant subi une extraction par entraînement est refroidi dans l'échangeur de chaleur à une température comprise entre 28 et 83°C en-dessous de la température d'entraînement, l'échangeur de chaleur permettant ainsi le maintien de la température du régénérateur indépendamment de la température d'entraînement.

7. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que la partie de catalyseur séparé du catalyseur combiné contient des composés contenant du soufre et des composés contenant de l'hydrogène qui proviennent de la charge d'alimentation, et l'étape d'extraction par entraînement élimine 45 à 55% des composés contenant du soufre et 70 à 80% des composés contenant de l'hydrogène dans la partie de catalyseur séparé.

8. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le courant de catalyseur combiné passe à contre-courant du gaz d'entraînement pendant l'étape d'extraction par entraînement.

9. Appareil pour mettre en oeuvre le procédé selon l'une quelconque des revendications 1 à 8, comprenant:

- un dispositif definissant une zone de conversion dans un réacteur ascendant, à travers laquelle un mélange comprenant du catalyseur et la charge d'alimentation passe, dans des conditions de craquage catalytique fluide, pour craquer la charge d'alimentation;

- un réacteur de craquage catalytique fluide;

- un dispositif pour faire passer le mélange du réacteur ascendant dans le réacteur de craquage catalytique fluide, le mélange ayant la température de sortie du réacteur ascendant lorsqu'il passe dans le réacteur;

- un dispositif pour séparer une partie du catalyseur du mélange, tandis que le reste du mélange forme un courant gazeux dans le réacteur;

- un dispositif pour chauffer la partie de catalyseur séparé, par une étape de chauffage consistant essentiellement à combiner la partie de catalyseur séparé avec une partie du catalyseur régénéré pour former un catalyseur combiné;

- un dispositif pour entrainer le catalyseur combiné par contact avec un courant de gaz d'entraînement pour former un courant de catalyseur ayant subi une extraction par entraînement;

- un régénérateur de craquage catalytique fluide pour produire la partie de catalyseur régénéré; et

- un échangeur de chaleur pour refroidir le courant de catalyseur ayant subi une extraction par entraînement, l'échangeur de chaleur étant situé à l'extérieur du réacteur, du régénérateur de craquage catalytique fluide, de façon à régénérer un courant de catalyseur refroidi par contact avec un courant contenant de l'oxygène dans les conditions du régénérateur de craquage catalytique fluide;

- un conduit d'effluent de catalyseur ayant subi une extraction par entraînement, fixé au dispositif d'extraction par entraînement du courant de catalyseur entre ce dispositif d'extraction par entraînement et l'échangeur de chaleur.

10. Appareil selon la revendication 9, caractérisé en ce que l'échangeur de chaleur est en amont du régénérateur.

11. Appareil selon la revendication 10, caractérisé en ce que le système de refroidissement de catalyseur est un échangeur de chaleur indirect pour refroidir le courant de catalyseur ayant subi une extraction par entraînement à une température suffisante pour provoquer le maintien du régénérateur à une température comprise entre 55°C au-dessus de la température d'entraînement et 871°C, de sorte que la partie de catalyseur régénéré produite a une température comprise entre 55°C au-dessus de la température d'entraînement et 871°C.

12. Appareil selon la revendication 11, caractérisé en ce que le dispositif pour séparer le mélange de la zone de conversion du réacteur ascendant comprend un système de cyclones clos connecté à la zone de conversion du réacteur ascendant.

13. Appareil selon la revendication 12, caractérisé en ce que le dispositif d'extraction par entraînement comprend un dispositif pour faire passer le catalyseur combiné à contre-courant du gaz d'entraînement.

Drawing