DE2638499A1 - CATALYTIC FLUID CRACKING PROCESS AND DEVICE FOR IT - Google Patents

Description

Dr D. Thomsen PATE N ANWALTS OFFICE

& Phone (089) 530211

... .... , ,, 530212

W. Wein K 3UTl telegram address) OC O Q / QQ

J expert * O O ö ^ y a Cable address PATENT LAWYERS Some: Frankfurt / M .: Dr. rer. nat. D. Thomsen Dipl.-Ing. W. Welnkauff

(Fuchshohl 71)

Dresdner Bank AQ, Munich, account 5574237

8000 Munich 2

Kalser-Ludwlg-Platz 6 August 26th 1976

Priority claim:

USA No. 6o8 352 August 27, 1975

Mobil Oil Corporation
New York, NY, USA

Fluid catalytic cracking process and apparatus therefor

The invention relates to an improved method and apparatus for controlling a catalytic fluid cracking system. In particular, the invention relates to a control element for the catalytic converter section a variable circulation of regenerated to spent catalyst in the regenerator.

The catalytic fluid cracking of petroleum fractions is a well-known refinery process. The catalytic cracking device itself contains a catalyst section, which is located in eiaora Bm & ktoisshsclmttt OMt®st9llt L3t _r os the Isat ^ lyti.T-Iv ^

Cracking occurs in conjunction with a regenerator section where coke is burned off on spent catalyst is dejected. The method works essentially as follows. Fresh feed material, usually preheated, in admixture with the catalyst undergoes cracking within the reactor section. The products will removed from the reactor in the vapor phase and to a product recovery section passed, the at least one main fractionator or a distillation column for separating the Contains products in the desired fractions. Spent catalyst caused by the cracking reaction with coke or carbon has been charged, is continuously consumed from the reactor to the regenerator through a conveying line Catalyst passed. In the regenerator, the coke or carbon is released through contact with an oxygen-containing gas burned down. Exhaust gas is diverted from the regenerator; regenerated catalyst is returned to the reactor via a standpipe put into circulation, where it is absorbed by the stream of fresh feed hydrocarbon material. The catalyst itself is finely divided and simulates a fluid in various parts of the catalytic converter section, as the designation expresses this procedure. In a typical embodiment, heat that has been generated in the regenerator is used is passed through the hot regenerated catalyst to the reactor to provide heat for the cracking reactions. Typical Fluid catalyst cracking systems are described in U.S. Patents 3,2o6,393 and 3,261,777,

The fluid catalytic cracking process has been effectively improved over the years. In particular, they are Development of zeolite catalysts with their greater activity and reduced coke formation and improvements in the design of the reactor section to improve riser-cracking.

More recent developments in regenerator section technology indicate at the same time a simplification of the device, a more efficient use of the heat developed during the regeneration, a contribution to better product quality and a reduction in the catalyst inventory. While conventional regenerator technology produces a regenerated catalyst with about 0.3% by weight of residual coke and an exhaust gas rich in carbon monoxide, the new technology leads to the formation of a regenerated catalyst which is essentially free of coke or carbon, ie less than about 0.08 wt%, and further to an exhaust gas wherein the CO (carbon monoxide) has been substantially completely _{burned to CO 3} (carbon dioxide), that is, the exhaust gas has a CO content of less than about 4,000 ppm and preferably less than about 2,000 ppm (as used herein, ppm refers to parts per million volunieri parts). With the help of the new technology, there is no longer the need for a CO steam boiler system such as is commonly used for CO combustion to complete and to gain the sensible heat , as complete CO combustion takes place in the regenerator itself. In addition to the simplified

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Device result further advantages from the new technology, e.g. more active regenerated catalyst, better gasoline quality, more effective transmission of coke burning generated heat to the reactor section and an exhaust gas composition that is suitable for direct emission into the atmosphere is ecologically more suitable. The usual catalytic fluid cracking technology is expedient, with the exhaust gas from the Regenerator section contains essentially more than about 4,000 ppm CO, here as an operation according to the "partial CO combustion procedure" designated. The procedure according to the new technology, wherein the CO content of the Exhaust gas is about 4,000 ppm or less, is used here as a working process according to the "complete CO combustion procedure" designated.

Despite the significant advantages of the new technology, its widespread use in the petroleum industry is questionable. For example, relatively small disturbances in the feed material can cause premature failure of those used in the regenerator Cyclone to remove regenerated catalyst from the exhaust gas. There is also the very serious problem whether available control systems make the catalytic cracking device sufficiently adaptable to accept changes in the Feed material quality without major or catastrophic disruptions that would stealthily cause the plant to come to a standstill.

The problems associated with the control of fluid catalytic systems that after complete CO

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Combustion working methods seem at first glance with the unusually high temperatures involved in the regenerator gets to communicate. However, it has been found that there are serious and deeper problems.

The object of the invention is therefore to create a method and a device for improving the catalytic fluid cracking.

According to the invention, this object is achieved by the method according to the claims and the device according to the claims resolved to carry out this procedure.

Thus, according to the present invention, there is provided an improved method for controlling the operation of a catalytic fluid cracking system having a reactor section and a regenerator section which operates on the full CO combustion mode of operation. In particular, a measured regenerator temperature is compared with a predetermined regenerator temperature or with a measured temperature difference within the regenerator, as will be explained in more detail below; the circulation ratio of regenerated to coke-laden catalyst within the regenerator section is set as a function of a function of this comparison in the direction of the readjustment of the measured temperature to the predetermined temperature . In a special embodiment, this concerns

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Method according to the invention furthermore a comparison of the carbon monoxide content of the exhaust gas exiting the regenerator section with a predetermined carbon monoxide content and a Adjustment of the air flow rate to the regenerator as a function of a function of this comparison in the direction of readjustment the carbon monoxide content to the predetermined carbon monoxide content.

In another particular embodiment, the invention relates to a control system for a catalytic fluid cracking device with a device for the adjustable circulation of a fraction of hot regenerated catalyst to coke-laden Catalyst, a device for measuring the deviation in temperature of the hot regenerated catalyst of a predetermined temperature and a device for adjusting the circulation which is responsive to this deviation in the direction of reducing the deviation.

The invention is explained in more detail below with reference to the drawing, for example. In the drawing mean

Fig. 1 is a schematic representation of a conventional catalyst section control system according to the full CO combustion mode works;

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Fig. 2 graphs of data generated by

Handling a mathematical model were generated;

3 shows a schematic representation of a catalyst section control system according to the invention.

A common control scheme for a catalyst section in the regenerator section operation after the full CO burn operation is shown in FIG. According to FIG. 1, the oil feed material, which may be preheated by the heater 2, is conducted via a line 1 to the lower end of the riser pipe 3. Heated catalyst from the standpipe 4 with a control valve 5 is combined with the heated oil in the riser 3 so that an oil / catalyst mixture rises in an ascending distributed flow until it enters the reactor 6 and is deposited as a dense bed 7. In the reactor 6, further fluidized contact between the oil and the catalyst particles can take place within the relatively dense fluidized bed 7. Generally, a greater proportion of the necessary cracking and contact of the oil with the catalyst takes place in the riser 3. products remain are separated at the upper end of the reactor 6 by centrifugal devices or settling devices (not shown ). The products are then passed overhead through line 8 to a product recovery section (not shown) which contains at least one fractionator. Temperature-

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Sensing devices 9, for example a thermocouple, are provided for determining the temperature inside the reactor 6 and for sending a signal to the temperature controller 1o, which shows the temperature in the reactor 6. If the temperature of the reactor deviates from the predetermined temperature, as defined by the fixed point 11 of the temperature controller 1o, the temperature controller gives a signal via a line 12 to adjust the valve 5 and so to adjust the temperature of the catalyst / oil mixture in the riser 3 in the direction of a reduction in the deviation of the measured temperature from the predetermined temperature, as defined by the fixed point 11 of the temperature controller 1o. In general, it is very desirable that fluctuations in the temperature within the reactor 6 and the products emerging from the line 8 are reduced to a minimum, so that disturbances in the main fractionator column are also reduced to a minimum. Spent catalyst from bed 7 is continuously led from reactor 6 through spent catalyst duct 13 provided with valve 14 and brought to the lower part of regenerator 15 to form a relatively dense bed 16. Luft.wird on the way via the air supply line 17, which is provided with a control valve 18, passed to the regenerator, where it flows through the disperser 19; it serves to maintain the bed 16 in the fluidized state and for the continuous conduction of catalysts through the riser pipe 2o as the dilute phase 21. In the upper part of the regenerator 15, exhaust gas is separated from the regenerated catalyst ; it exits on the way via line 22. Regenerated cata-

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lysator settles to form a relatively dense bed 23. The regenerated catalyst bed 23 is at a much higher temperature than the spent catalyst from bed 7 due to the burning off of coke that takes place in regenerator 15. Typically this difference can be about 208 ° C (375 ° F). Within the regenerator itself, the bed 23 and the exhaust gas in the chamber are significantly hotter than the spent but partially regenerated catalyst from bed 16, with differences of about 55 ° C (100 ° F) not uncommon. A composition sensor 24, which indicates the content of carbon monoxide and oxygen in the exhaust gas, generates a signal which is indicative of the composition in question. The valve 18 is usually controlled by the intervention of an operator so that the flow of air and thus the content of CO and oxygen in the exhaust gas are adjusted. On the other hand, the signal generated by the composition sensor 24 is passed on to the composition controller 25. The regulator 25, which is provided with fixed points 26, sends a signal to the line 27, this signal being indicative of the deviation of the carbon monoxide composition of the exhaust gas from the fixed point 26; Thus, the control valve 18 is set in the direction of reducing the deviation of the measured composition from the predetermined composition, as determined by the fixed point 26. In general, the fixed point is set to a CO content lower than 2,000 ppm; the exhaust gas generally contains about 2% excess oxygen gas. Although not specifically shown, the valve 14 is usually connected to the valve 5 in such a way that a solid

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Ratio of the amount of catalyst in the generator 15 to the amount of catalyst in the reactor 6 is maintained.

With the control system described above for an operation in the full CO combustion operation the process is generally performed in such a way as to ensure that substantially all of the Coke or carbon deposited on the catalyst in the reactor section is burned in the regenerator; this means that the residual carbon on the regenerated catalyst is generally less than about 0.05% by weight. High temperatures are obtained in the regenerator; the regenerated catalyst in bed 23 is generally on one Temperature of at least about 732 ° C (about 135o ° F). In the absence of fluctuations in the amount of coke or carbon, settled by the feed material during cracking, or fluctuations in feed material temperature or from other disturbances, the control system described results in a smooth operation of the catalytic converter section. However have Investigations of the control system showed that its adaptive behavior sudden changes in the amount of coke formed and thus variations in feed quality is considerably less than when the partial CO combustion procedure is used. Also are the changes that occur are counterproductive with regard to the product composition. The reasons for this bad Adaptive behavior should be examined irii individuals. at the full CO combustion operation because

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2838499

all coke is essentially completely _{burned to CO 2} in the regenerator, a change in the rate of coke formation to temperature excursions in the regenerator which are greater than with the partial CO combustion procedure. While some measure of control can still be achieved in the partial CO combustion operation by changing the air flow rate to the regenerator, this choice is relatively ineffective in the full CO combustion operation. Computer simulations of the effect of changes in air flow rate in two modes of operation of such operations are shown in FIG. As can be seen, reducing the air flow rate in the usual procedure (from about 1% excess oxygen to about 0.25%) results in a substantial decrease in both the catalyst and exhaust gas exit temperatures, as indicated by curves Tc and Ta, respectively is. In contrast, a decrease in the flow rate in the full CO combustion mode causes relatively little changes in these parameters. The change is also going in the opposite direction; this means that there is an increase in Tc and Ta. Part of the explanation for the relative insensitivity of regenerator temperature to air flow rate in the full CO combustion procedure is that the carbon on regenerated catalyst is essentially unaffected by change in air flow rate, while it is greatly affected in the conventional procedure. Thus a change in the quality of the feed material produces either a decrease or an increase in the speed of the coke

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education leads to an irregular or excessive disorder of the Regenerator operation with the full CO combustion mode of operation because of the larger temperature excursions and smaller ones Response to the air flow rate as a peculiarity of such a way of working.

In the above investigations, the

Temperature conditions as such have not been mentioned. With respect to the apparatus of Figure 1, typical temperatures are about 677 ° C (125o ° F) for the dense bed 16, about 704 ° C (130o ° F) in the center of the diluted bed 21, and about 732 ° C (135o ° F) for the sealed bed 23 and the exhaust gas exiting via line 22. These temperatures, particularly in beds 21 and 23, are significantly higher than those commonly used in the partial CO combustion operation; they seem to be necessary to initiate the combustion of CO to CO «. These temperatures cannot currently be reduced noticeably without overriding the control limits of the controller 25; nor can they noticeably be increased without exceeding the normal system limits of the facility and the risk of catalyst damage. For example, the high regenerator temperatures that are continuously maintained in the full CO combustion mode of operation mean a third factor, namely besides the larger temperature excursions and lower responses to the air flow rate, whereby the current control systems are only slightly adaptable to changes in the feed material quality. However, significant advantages result from the present invention _/ itself

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if it were possible to close the regenerator in the full CO combustion mode at a lower temperature operate.

The poor adaptability of the currently known control systems for the operation of the complete CO combustion operation results in large changes in the catalyst circulation rate. For example, a change leads in the feed to such, whereby larger amounts of carbon or coke are deposited, i.e. to such of lower quality, an increase in the temperature of the dense bed 23 (see FIG. 1) and one Increase in the temperature determined by the thermocouple 9. On the other hand, this leads to the regulator 1o acts on the valve 5 in the direction of a reduction in the catalyst / oil ratio, so that regenerator and product temperatures are readjusted to values within the limits described above. However observed it is believed that a lower quality of the feed material requires a higher rigor of treatment in order to achieve optimal distribution is complied with by cracked products. Hence, the setting of the catalyst / oil ratio is how it's done the control system is induced, counterproductive; its extent is another characteristic of the bad Adaptation behavior of the known control systems.

The relatively inadequate adaptive behavior of the usual control scheme in the case of complete CO control

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combustion operation a serious shortcoming of the system, which to some extent has very desirable advantages, such as described above, which can be obtained using the system, counteracts.

In contrast, an improved control system is created according to the invention, whereby the adaptive behavior of the catalyst section of a fluid catalytic cracking unit which is based on the full CO combustion mode of operation works, is improved. The improved regulation is obtained in that the circulation of variable proportions or ratios of regenerated catalyst to used catalyst to vary the temperature the latter is provided in a regulated manner. The inclusion of the regulated circulation element is shown in FIG. 3 illustrated. The present invention not only ensures an improved adaptation behavior in the event of disturbances, such as e.g. in the event of changes in the quality of the feed material, but also results in improved regenerator operation as described in U.S. Patent Application No. 38o 173 (submitted July 18, 1973); the present invention relates to a further improvement of the said USA patent application, what is referred to here.

A special embodiment according to the invention is will be described below with reference to Figure 3 of the accompanying drawings. In Fig. 3 are the essentials

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Elements that are described above with reference to FIG. 1 are indicated by the same reference numerals. In addition, according to the invention, one or more lines 28 for transferring regenerated catalyst 23 to partially regenerated catalyst 16 are provided. Alternatively, a line 28 can recycle regenerated catalyst directly to the spent catalyst transfer line 13, as described in U.S. Patent Application No. 38o 173 (see above) is shown. In any case, the one or more lines 28 are provided with effective flow control devices, eg valve devices 29, which are able to vary the recycle ratio, ie the ratio of the weight of regenerated catalyst which is passed on the way via the line 28 , to the weight of the used catalyst, which is transferred on the way via the transfer line 13 for used catalyst, in the unit of time. Essentially, the function of the one or more conduits 28 is to return a portion of the much hotter regenerated catalyst 23 to the cooler catalyst 16, thereby raising the temperature of the latter. Appropriately, the catalyst in bed 16 as well as that which is transferred from bed 7 by way of the line 13 , is referred to as "spent" catalyst .

Furthermore, a thermocouple or another temperature sensing device 3o is provided, whereby a kiln

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position of the temperature in the upper part of the regenerator 15 is generated. This representation becomes the temperature controller which is provided with a fixed point 32. A deviation in temperature as indicated by the temperature sensing device 3o is measured from the predetermined temperature, as determined by the fixed point 32, causes that the controller 31 gives a signal on the line 33, which on the other hand causes a valve device 29 to adjust the circulation ratio: changes towards a readjustment of the measured temperature to the predetermined temperature. For example, if the If the temperature measured by the device 3o exceeds the predetermined temperature, the valve devices 29 opened, so that the circulation ratio is increased and the temperature in the upper part of the regenerator 15 is decreased.

Alternative locations for the temperature sensing device 3o are, for example, locations in the exhaust pipe 22 or in the dense fluidized bed 23.

An optional system (not shown) for regulating the regenerator temperature is provided by two thermocouples, which are arranged in beds 23 and 16, respectively. The signals obtained in this way are sent to a controller, which the temperature difference with a predetermined temperature difference compares and generates a control signal which - fed to valve 29 - the circulation ratio in the direction of a reduction in the deviation of the measured temperature

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- 17 difference from the predetermined value changed.

Although this embodiment of the invention according to Fig. 3 uses automatic controllers 1o, 25 and 31, you can also use a manual control instead of one or of run several of these facilities. However, automatic regulators are preferred; for this one can use those of the PDI type (proportional-differential-integral) or use less complicated types, depending on the work requirements .

The function of the flow control element to improve the adaptability of a catalytic converter section when operating in the full CO combustion mode, it is best to perform a series of calculations (see below) shown. For verification purposes, the accepted the following conditions:

A fixed part of the plant = · adiabatic in operation

3 Volume of the dense phase: 158.6 m (5βοο cubic feet)

ty.

Volume of the diluted phase: 396.5 m (14,000 kufoik feet)

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Used catalyst: Circulation:
Carbon content: Catalyst exposure temperature: Total material input:

60 t / min.
o _f 9o% by weight
516 ⁰ C (960 ⁰ F)

12o t

(80% in a tight bed, 2o% in the riser pipe)

Catalyst residence time in the dense catalyst bed and in the riser pipe: 2 min. (Without circulation)

Regenerator air:

Low rate:

High rate:

Air inlet temperature:

9o6 000 engl. Pounds / h 1 12o 000 engl. Pounds / h 163 ° C (325 ° F)

The calculations were made assuming uniform mixing of the catalyst particles and a slow rate of carbon burning proportional to the average concentration of carbon on the dense bed catalyst. The burning of CO to CO _{3 occurs} at a slow rate in the dense fluidized bed. The rate of this reaction is much higher in the gas phase in the absence of catalyst. The calculations were carried out under two assumptions for the rate of CO reaction in the riser:

1) homogeneous

2) Rate of 10% of the homogeneous gas phase rate

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For rapid, homogeneous combustion of carbon monoxide in the gas phase, the temperature must be above 677 ° C (125o ° F).

A number of calculations (not shown here) were carried out at a low air rate. This was undesirable residual coke on regenerated catalyst and high CO content in the exhaust gas; as soon as circulation of regenerated When catalyst was practiced, temperatures rose and the amount of carbon burned increased; however also took the CO content of the exhaust gas beyond desired limits due to insufficient air volumes; also was the oxygen content of the exhaust gas zero. A process of this type is considered undesirable because of the high concentration of CO in the exhaust gases.

A more significant process is providing enough oxygen to burn the carbon to CO-, the table below I illustrates the data obtained assuming homogeneous CO combustion in the riser and high levels Air rates.

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- 2ο -

Table I.

(High air rate - homogeneous CO combustion in the riser pipe)

Temperature (F)

Carbon on regenerated catalyst (wt. %)

Escaping gas (Mo1 .-%)

Circulation Catalysis Upper Upper Upper Upper CO O ₂ ver satorge part part part part ratio raisch to aes of of of Rain poetry Climb poetry Climb rator Betts pipe Bed pipe

96o 1172 14o4 o, 21 o, o11 o, oo4 2.42 1180 1291 14oo 0.06 o, o1 o, oo4 2.7 1243 1321 1393 o, o44 o, o16 o, oo4 2.4 1271 133o 1383 o, o4o o, o2o o, oo7 2.47

Table II below illustrates another variation using a high air content and the CO burn rate was assumed to be only 10% of the homogeneous CO burn rate.

This series concerns 3o% of the used catalyst, mixed with catalyst, passed overhead from the dense Bed, and then ascent through the riser. 70% was mixed with regenerated catalyst in the dense bed.

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Table II

(High air rate; CO combustion rate 1o% of the homogeneous)

Catalyst temperature (° F)

(Wt%)

Carbon on escaping regenerated gas (ΜοΙ, -%)

0 96ο 1129 1 1222 1298 2 1252 13o1 3 1269 13o5

CO ° 2 1.81 5, ο ο, 12 2.2 ο, 22 3.1 o, 25 3.48

Umlauf- Kataly- Upper Upper Upper Upper

versatorge part part part part

proportion mixed to the des des des

Rainproof climb- tight climb

rator bed tube bed tube

1323 o, 221 o, 131

141o o, o37 o, o32

136o o, o36 o, o4

135o o, o34 o, o49

The above calculations illustrate the control obtained by varying the circulation ratio of o to 3 is obtained. As a result of the inclusion of the circulation element in the control system there will be variations in quality of the feed material or other disturbances that lead to temperature changes in the regenerator within the Regenerator moderates itself, allowing changes in the temperature of the regenerated catalyst that is passed to the reactor and counterproductive changes in the catalyst / oil ratio are eliminated or reduced.

While the illustrations in Tables I and II above illustrate the process with circulation ratios of

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0 to 3 show which indicates a preferred range circulation ratios of up to about 5 can be more advantageous Way to be used. It is preferred that the control method is set at a circulation ratio of about 1 being, being the circulation ratio in the absence a malfunction.

The following example is derived from the mathematical simulation of the behavior of a regenerator; it serves to illustrate the improved adaptation behavior according to the invention; however, this does not limit the invention.

With the illustrative assumption of a sudden change in the feed material being fed to a fluid catalytic cracking apparatus of the present invention and a corresponding change such that the carbon content on spent catalyst goes from 0.7o wt% to 0.65 wt% falls and that a maintenance of the CO content in the exhaust gas at a maximum level of 0.2o% is required, this change in the feed material leads to a reduction in the temperature in the dense bed 16 and at the upper end of the riser pipe 2o (see Fig. 3 ) and excessive CO emissions as the amount of carbon fed to the regenerator is reduced. This is illustrated by comparing items 3 and 8 according to Table III below. Without changing the circulating

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Ratio can not adjust the air flow rate take place in order to adjust CO emissions to the required values again and also counterproductive changes to be avoided in the catalyst / oil ratio (cf. items 5 to 8 according to Table III below). When there is a change however, the circulation ratio of 1 to 2 will result in a re-establishment of the CO control along with others desired parameters achieved (see. Items 3 and 11 of Table III below); this counteracts the compulsion for any major perturbations in the catalyst / oil ratio.

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- 24 Table III Regenerator Behavior

Pos. Air flow / temperature ( ⁰ F) exhaust gas (vol .-%) carbon

No carbon on regenerative

to the rain- dense upper over-ridden

rator bed part d. shot catalyst

(English pound / incline- 0 CO CO (wt .-%) engl. Lbs.) Pipe

(For o, 7o wt .-% C on the spent catalyst; circulation ratio 1, o)

(1) 11 (2) 12th (3) * 13th (4) 14th

1231 1275 O 0 2.36 15.1 o, 11 1242 13o5 2 0 o, 32 16.4 o, o8 1242 1316 , 87 o, 14 16, ο o, o6 1231 1311 , 18 o, 2o 15, ο o, o5

(For 0.65 wt% C on the spent catalyst; Circulation ratio 1, o)

(5) 11 1213 1259 O O 1.68 15.4 0, 12th (6) 12th 1222 1283 1 , 22 o, 23 16.3 0, o9 (7) 13th 1218 1287 3 , 31 o, 25 15.5 0, o7 (8th) 14th 1192 1264 , 06 o, 57 13.9 0, 08

(For 0.65 wt% C on the spent catalyst; Circulation ratio 2, o)

(9) 11 12

1231 1258 0 O 2.27 15.1 o, 1o 1229 1269 0 , o5 o, 38 16.4 o, o9 1255 1299 2 , 77 o, 14 16.1 0.06 1216 1264 , 86 o, 45 14.2 o, o7

(11) * 13 (12) 14

3t
These positions indicate optimal operation

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Claims (6)

Claims Fluid catalytic cracking process for cracking a hydrocarbon feed stream, wherein the stream is hot regenerated catalyst in a reactor section maintained under catalytic cracking conditions to form of cracked products and catalyst contaminated by coke is brought into contact and wherein the cracked Products and the contaminated catalyst are separated and recovered therefrom in the reactor section and further wherein the recovered contaminated catalyst continuously through a regenerator section operating in full CO combustion mode is circulated, whereby the coke or carbon burned off by contact with an oxygen-containing gas and hot regenerated catalyst at a temperature substantially higher than that of the contaminated catalyst is formed, and wherein the regenerator section with an adjustable device for the circulation of a part d = s regenerated catalyst is provided to the recovered contaminated catalyst and further hot regenerated catalyst is recirculated to the reactor section, characterized in that that for the improvement of the adaptation behavior in the control the temperature of the hot regenerated catalyst compared to a predetermined temperature yielding a temperature offset for the regenerated catalyst and circulating hot regenerated catalyst to spent catalyst within the regenerator section 709809/0877 is set to change the circulation ratio in the direction of reducing the temperature deviation. 2. The method according to claim 1, characterized in that the circulation ratio is within the range from ο to about 5 is set. 3. The method according to claim 1, characterized in that the circulation ratio is within the range from ο to about 3 is set. 4. The method according to claim 2, characterized in that the carbon monoxide content of the regenerator section discharged exhaust gas compared with a predetermined carbon monoxide content to determine a deviation in the carbon monoxide content and the flow of the oxygen-containing gas to the regenerator in the direction of a reduction in the deviation in Carbon monoxide content is adjusted. 5. The method according to claim 4, characterized in that the predetermined carbon monoxide content has a value of up to to about 2,000 ppm. 6. Device for performing the method according to the preceding claims for cracking a hydrocarbon feed stream, wherein the stream with hot regenerated catalyst in a reactor section which is under catalytic Cracking conditions is maintained, with the formation of 709809/0877 cracked products and catalyst contaminated by coke is brought into contact and wherein the cracked products and separating and recovering the contaminated catalyst in the reactor section, and further wherein the recovered contaminated catalyst continuously through a regenerator section operating in full CO combustion mode is circulated, whereby the coke or carbon burned off by contact with an oxygen-containing gas and hot regenerated catalyst at a temperature substantially higher than that of the contaminated catalyst and wherein hot regenerated catalyst is further recycled to the reactor section by means within the regenerator section for the adjustable circulation of a fraction of the hot regenerated catalyst to recovered contaminated catalyst, a device for generating a signal that the Indicates deviation of the temperature of the hot regenerated catalyst from a predetermined temperature, and one on this means for setting the adjustable circulating means, which is used to respond to this signal indicating the deviation to change the circulation ratio in the direction of reducing the deviation. 709809/0877 If Blank page