JPS6156269B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for catalytic cracking of hydrocarbons without the addition of hydrogen. More particularly, the present invention relates to an improved method for controlling the combustion of carbon monoxide in the regenerator of a catalytic cracking system by adding trace amounts of an oxidation catalyst, such as platinum, to the cracking catalyst. One embodiment involves contacting a side stream of cracking catalyst with a solution of a metal compound, thereby controlling the combustion of carbon monoxide in a regenerator of a catalytic cracking device. A typical example of catalytic cracking of hydrocarbons using a moving bed that has been carried out industrially is known as thermal catalytic cracking (TCC). In this method, the catalyst has an average particle size of approximately 0.4 to 6.4 mm (approximately 1/64 to 1/64 mm).
1/4 inch), preferably about 3.2mm (about 1/8 inch)
It is in the form of beads or pellets. The active hot catalyst beads flow co-currently downward through the cracking reaction zone with the hydrocarbon feedstock. In this reaction zone, the hydrocarbon feedstock is endothermically cracked into lower molecular weight hydrocarbons, while coke is deposited on the catalyst. At the lower end of the reaction zone, the hydrocarbon products are separated from the coke deposited catalyst;
It will be collected. The coke-laden catalyst is then flowed downward through a regeneration zone, which is supplied with air, part of which flows countercurrently upwardly to the coke-laden catalyst, and the remaining air partially Flow cocurrent with the regenerated catalyst. Two types of flue gas are produced, including carbon oxides. The regenerated catalyst is separated from the flue gas and then lifted by the action of air or mechanically to the top of the reaction zone. Fluid catalytic cracking of hydrocarbon oils is mainly used in refining processes. The plant usually produces about 79,500 to 2,146,500 Kl/day of fresh raw materials (about 5,000 to
135,000 barrels/day). Most plants are very large and at least
The plant can process 636,000Kl/day (40,000 barrels/day).The catalyst section of the plant consists of a cracking section where heavy hydrocarbon feedstock is cracked by contacting it with a fluidized cracking catalyst, and a fluidized catalyst where coke is precipitated during the cracking operation with air. and a regeneration zone where it is regenerated by combustion. All plants have a fairly large fixed charge of cracking catalyst which is continuously circulated between the cracking zone and the regenerator zone. The fixed amount of this circulating cracking catalyst in is in the range of 50-600 tons.Although the design structure of each individual plant is different, the essential elements, especially the catalyst flow, are similar to the catalyst section of a conventional fluid catalytic cracking plant. 1 and 2. The cross-sectional portions shown in FIGS. 1 and 2 represent a typical example of the catalyst section of a commercially available fluid catalytic cracking device. .Referring to Figure 1, it is approximately 316 to 538℃ (approximately
A hydrocarbon feedstock 2, such as gas oil with a boiling point of 600-1000〓), is sent to the bottom of the riser 4 after preheating and is connected to a hot regenerated catalyst introduced by a distribution pipe 6 equipped with a flow control valve 8. mixed. Therefore, at least about 510℃ (about 950〓),
More generally, at temperatures of at least 538°C (1000°C), a suspension of catalyst in hydrocarbon vapor forms at the bottom of riser 4 and flows upwardly at hydrocarbon conversion conditions. The suspension initially formed in the riser maintains a hydrocarbon retention time of 1 to 10 seconds during passage through the riser. The hydrocarbon vapor-catalyst suspension produced in the riser reactor is fed to one or more surrounding riser outlets represented by cyclone separators 14 at least 482 mL before being discharged to the cyclone separation zone.
℃ (900〓), more commonly at least 538℃
(1000〓) is fed upwardly through riser 4 under hydrocarbon conversion conditions. A plurality of cyclone separators may be provided in combination with first and second cyclone separators coupled or separate from the riser outlet to separate catalyst particles from hydrocarbon vapors. Separated hydrocarbon vapors are passed from separator 14 to plenum chamber 16 from where they are removed by conduit 18. These hydrocarbon vapors are sent by conduit 18 to a fractionator (not shown) along with gaseous substances which are separated by stripping gas, which will be described below. The catalyst separated from the hydrocarbon vapor in the cyclone separator is Datepreg 2.
A dipleg, indicated by 0, is fed to a dense fluidized bed of separated catalyst 22 held near the top of riser conversion zone 4. The catalyst bed 22 is maintained as a fluidized catalyst bed that moves downwardly countercurrently with the rising gaseous material. The catalyst flows downwardly through the stripping zone 24 immediately below and countercurrently with the rising stripping gas which is introduced into the lower part of the stripping zone by conduit 26. A buffle 28 is provided in the stripping area to improve the stripping operation. The catalyst is maintained in the stripping zone 24 for a sufficient time to desorb the deposited feedstock at elevated temperatures, which is then carried upwardly by the stripping gas. The stripping gas with desorbed hydrocarbons is passed through one or more cyclone separators 3
2, where the entrained catalyst particles are separated and returned to the catalyst bed 22 by dipleg 34. The hydrocarbon conversion zone consisting of the riser 4 may terminate in the upper flared section of the catalyst recovery vessel with a commonly known birdcage discharge device or with an open-ended T without being directly connected to the cyclone catalyst separator. A mold connection device may be provided at the riser outlet. The cyclone separator may be located away from the riser outlet so that initial catalyst separation is effected by varying the velocity and direction of the discharged suspension;
The vapor, which is thereby less entrained with catalyst particles, is sent to one or more cyclone separators before being sent to the product separation step. In any of these embodiments, gaseous materials consisting of stripping gas, hydrocarbon vapors and desorbed sulfur compounds are conveyed from a cyclone separator, represented by separator 32, to a plenum chamber and via conduit 18. It is then removed along with the hydrocarbon products of the cracking operation. Gaseous substances containing hydrocarbon vapors are transferred to conduit 1.
8 to a product fractionation step (not shown). The hot catalyst stripped at high temperature is removed from the lower part of the stripping section by conduit 36 and sent to a fluidized catalyst bed where regeneration takes place in a catalyst regeneration section. A flow rate control valve 38 is provided in the conduit 36 that sends the coke deposited catalyst.
is provided. This type of catalyst regeneration operation is referred to as a spiral catalyst regeneration operation, in which the catalyst bed rotates or circulates around the vertical axis of the vessel, and this action results in the introduction of spent catalyst tangentially to the rotating catalyst bed. It is promoted by That is, the catalyst introduced tangentially at high temperature is further mixed with hot regenerated catalyst or catalyst to be regenerated at high temperature, rotated about the vertical axis of the regenerator, and placed in the catalyst removal channel adjacent to the regeneration gas distribution grid. Move downward toward the bathtub (sometimes referred to as the "bathtub"). In this catalyst regeneration zone, the regeneration gas, consisting of the flue gas products of the combustion of carbonaceous materials, moves vertically upwards through a horizontally moving circulating catalyst and towards a cyclone separator at the top of the catalyst bed. Move to. In the embodiment shown in FIG.
The catalyst introduced tangentially into the regenerator by causes the catalyst to circulate clockwise. As the catalyst bed continues to operate in circulation, some catalyst particles migrate downward from the top of the mass of catalyst particles suspended in the regeneration gas and flow toward a catalyst removal funnel 40 in a vessel adjacent to the catalyst inlet. . This population of suspended catalyst particles in the regeneration zone 42 surrounds a population of circulating catalyst particles 44 suspended in an upwardly flowing oxygen-containing regeneration gas introduced into the lower part of the regeneration zone 42 by a distributor 46. The density of will vary depending on the amount of regeneration gas used. The circulating suspended catalyst particle population 44, which is typically regenerated with an oxygen-containing gas to remove carbonaceous deposits by combustion, is a rotating suspended catalyst particle population 44 whose density varies with respect to the direction of catalyst flow. The suspended catalyst particles 48 present in the upper part of the regeneration zone above this population have a much lower density. Under carefully selected, relatively low regeneration gas velocity conditions, there is a sharp boundary between a dense fluidized bed of suspended catalyst particles and an overlying, more dispersed, dilute suspended catalyst phase. . However, as the regeneration gas velocity increases, the boundary line weakens and the suspended catalyst is generally around 481Kg/
m ³ (approximately 30 pounds per cubic foot). Preferably, the density of the lower catalyst bed is at least 20 pounds per cubic ^foot . As shown in FIG. 1, a regeneration gas distribution grid 50 is provided in the lower cross-section of the regeneration vessel 42 for regulating the flow of regeneration gas directed vertically above it. Even in the case of a generally horizontally circulating catalyst mass in this configuration, the flow of regeneration gas flows generally vertically upwards through the catalyst mass, and the regeneration gas introduced into the catalyst bed through the grid is regulated by the holes in the grid. , the air velocity is adjusted. After contacting the catalyst in the regeneration zone, the oxygen-containing combustion gases are separated from entrained catalyst particles by an upper spaced cyclone separator. The cyclone combination shown in FIG. 1 corresponds to that shown in FIG. The catalyst particles separated from the flue gas passing through the cyclone are returned to the catalyst mass below by diplegs. The regenerated catalyst removed by funnel 40 as described above is conveyed to hydrocarbon conversion riser 4 by standpipe 6. The regenerator shown in FIGS. 1 and 2 is typically designed to prepare a flue gas containing significant concentrations of carbon monoxide as well as carbon dioxide. In practice, a typical CO ₂ /CO ratio is approximately 1.2. As mentioned above, it has been desired to reduce the amount of carbon monoxide released as much as possible from the regenerator of the cyclic catalytic cracking method in which hydrogen is not added. Previously proposed solutions include raising the temperature of the regenerator sufficiently to thermally combust the CO, or incorporating cracking catalysts such as chromium or iron to catalytically combust the CO. However, the amount of CO emitted cannot be sufficiently reduced, and if it is deliberately reduced sufficiently, the operation becomes too expensive or side reactions occur and the desired product cannot be obtained. occurred. The increased production of coke during cracking not only unbalances the heat balance of the entire circulating cracking unit, but also the increased production of light gases that affects the compressor and the entire gas plant, i.e. the C ₄ ^-gas of the product. This would impose an unreasonably large capacity on the gas plant for a series of separation operations to break down the fraction into its components. Accordingly, an important object of the present invention is to provide a new method for reducing the amount of carbon monoxide generated in a cyclic catalytic cracking process without the addition of hydrogen. Another object of the invention is to provide new catalysts for such processes. According to the invention, the catalyst, which has been in contact with the raw material in the reactor under cracking conditions without addition of hydrogen, is passed through an external circuit equipped with a regenerator and returns the catalyst in regenerated form to the reactor. The transferred mass contains platinum group metals in an amount sufficient to catalytically oxidize carbon monoxide in the regenerator, but insufficient to substantially increase coke and hydrogen production from the feedstock under the cracking conditions. A catalyst regeneration cycle catalytic cracking method comprising a catalyst containing a metal or rhenium, wherein the platinum group metal or rhenium is applied to the catalyst while the catalyst is passing through the circulation path. A contact cracking method is provided. As can be seen in FIG. 1, the term "fixed amount of circulating catalyst" includes catalyst in riser 4, catalyst in dense bed 22, catalyst in the dense bed of stripper 24, catalyst in the dense bed of regenerator 44, etc. catalyst in line 36 and standpipe 6, suspended catalyst in the reactor and regenerator cyclones and dilute phase, etc. Since the regenerator operates at a temperature greater than approximately 538°C (approximately 1000°) and the reactor operates at a temperature greater than 427°C (800°), this fixed amount of circulating catalyst is exposed to very high temperatures at both locations. , which is substantially higher than approximately 316℃ (approximately 600〓). In actual operation, the catalytic activity of the circulating catalyst tends to decrease with time, so in order to keep the catalytic activity at the optimum condition, approximately 1-2% of the fixed amount of circulating catalyst should be used each day.
% of fresh catalyst. This replenishment amount is approximately equal to the daily removal and loss of aged circulating catalyst portions. This supplementary catalyst is typically added to the regenerator through a hopper and conduit (not shown). The platinum group metal may be a constituent of all the catalyst particles or a part of the catalyst particles. The conditions regarding its concentration need only be sufficient to cause the carbon monoxide to react with oxygen to form carbon dioxide, and at the same time the conditions in the regenerator must be sufficient to support this combustion, such as a sufficiently high temperature and Maintains sufficient air volume. Conversely, the amount of platinum group metal should not be so great as to adversely affect the cracking operation. This upper limit on the amount of platinum group metal depends in part on the actual product production and the cracking equipment, including auxiliary equipment and downflow product cracking equipment. This upper limit of platinum group metal should not exceed the capacity of the cracking equipment. Also, when considered in practice, each of the seven metals of the platinum group defined herein has a different degree of effectiveness for its intended use in this device. Therefore, the upper and lower limits of the amount of metal used are inclusive values for the entire group. Therefore, specific individual items belonging to this group are not necessarily within a practical range. For example, a suitable upper limit for the amount of platinum group metal used is about 100 ppm by weight of the final catalyst composition. Although this value is an appropriate upper limit for the group, it is too high for certain species in this group. For example, in the case of platinum and iridium, a preferred upper limit is about 10 ppm. A lower limit is also specified for the amount of "platinum group metal" used in this catalyst, but in the case of numerical values specified for groups, it is necessary to carefully consider each individual item. That is, a lower limit of platinum group metals of about 0.1 ppm or even 0.01 ppm is appropriate when several metals such as platinum are taken into account;
This value is lower than the appropriate minimum usage of metals such as rhenium. However, in any case, the most appropriate amount of platinum group metal to be used is closely related to how effectively it works in the endothermic cyclic catalytic cracking process without addition of hydrogen. The amount used should be selected to maximize the combustion of carbon monoxide taking into account the coking characteristics of the particular feedstock or feedstock slate and/or operating conditions such as temperature conditions based on the equipment. In some cases it is important that substantially all of the carbon combusted in the regenerator is oxidized to carbon dioxide. In other cases, it is desirable for only some of the carbon to be fully oxidized to carbon dioxide, and for some to be partially oxidized to carbon monoxide.
By using the catalyst of the invention it is possible to select the exact amount of heat generated in the regenerator as a function of the effective combustion of carbon monoxide.
burn off some of the carbon monoxide present (thereby reducing residual coke on the regenerated catalyst,
(to increase the activity of the regenerated catalyst), the temperature of the regenerator can be raised by burning the remainder outside the regenerator, for example in a steam-generating CO boiler. As mentioned above, the novel catalyst of the present invention can be used alone in cyclic catalytic cracking operations or in admixture with other conventional cracking catalysts. In any of these embodiments, the amount of platinum group metal used can vary within the aforementioned limits. It is desirable to vary the amount of platinum group metal used depending on the operating time. That is, adding fresh catalyst containing a relatively large amount of platinum group metal (e.g., about 1 to 50 ppm based on total catalyst weight) to a cyclic cracking system that is operating with a platinum group metal-free catalyst. It is preferred to first replenish and then further replenish and modify fresh catalyst with a relatively low content of platinum group metals, so that the total content of active platinum metal relative to the total amount of catalyst is desired. value, for example around 0.05 ~
Make it 5ppm. Since the amount of platinum group metals used is very small,
It is very difficult to analyze the morphology of the metals on the catalyst during operation, especially after multiple runs, cracking and regeneration cycles. The metal may be added to the replenishment cracking catalyst after it has been previously prepared for introduction into the regenerator through the hopper and conduit. Metals may also be introduced during the production of cracking catalysts as described above. Alternatively, the metal may be introduced into the non-cracking catalyst, which in turn may be introduced into the supplementary cracking catalyst, possibly together with a binder. The platinum group metal may be present together with a cracking catalyst such as an elemental metal, an oxide, a sulfide, a halide, a sulfate, or a carbide. The catalyst composition may contain as one component, substrate or binder silica, alumina, zirconia, magnesia, clay, mixtures thereof and/or amorphous or crystalline compounds thereof or mixtures thereof with substances such as titania-zirconia. It may have. The cracking component may be amorphous silica-alumina, acidic clays, acidic crystalline aluminosilicate zeolites, especially those with very low alkali (e.g. sodium) content, and/or other known materials. In order to incorporate platinum group metals outside of the cracking/regeneration equipment, the preformed cracking catalyst composition or one or more components thereof may be combined with the preformed cracking catalyst composition or one or more components thereof as necessary to provide the predetermined amount of metal required by the present invention. in contact with a solution containing a quantity of a metal compound,
This is done by means such as impregnation, ion exchange, and vapor deposition. The platinum group metal may be mixed in at any stage of catalyst production, or may be mixed into an unfinished catalyst. Examples of suitable platinum group metal compounds include metal halides (preferably chlorides), nitrates, amine halides, oxides, sulfates, phosphates,
and other water-soluble inorganic salts, metal carboxylates or alcoholates of 1 to 5 carbon atoms.
Specific examples include palladium chloride, dichloroplatinic acid, ruthenium pentaammine chloride,
Examples include osmium chloride perrhenic acid, dioxobis(ethylenediamine)rhenium chloride (), and rhodium chloride. The platinum group metal may be incorporated into the cracking catalyst while it is in the regenerator.
For example, the metal component may be added to the regenerator as an emulsion, suspension or liquid in a liquid carrier such as fuel oil, air or water. The metal component, ie pt, pd, Ru, Ir, Os, Rh or Re, can be in either metallic or non-metallic form which is "degradable". For example, colloidal platinum suspensions; platinum dispersions on inorganic matrices such as alumina (such matrices having a particle size less than about half the average particle size of the catalyst, e.g. colloidal alumina); fuels. Suspensions of the foregoing dispersions in fluid carriers such as oil, air or water; and vapors of volatile metal compounds in suitable carriers such as inert gases. Generally, when the decomposable metal compound comes into contact with the cracking component in the cracking/regeneration device, it deforms and becomes intimately and irreversibly bonded to the cracking component. That is, the decomposable metal compound does not retain its original form and cannot be easily separated and recovered by normal physical means. The decomposable metal compounds introduced directly into the cracking/regeneration equipment include those mentioned above, such as adding an appropriate amount of an oil-soluble or oil-dispersible metal compound to a hydrocarbon feedstock such as gas oil to crack the feedstock. It combines with the catalyst during the reaction. Such compounds include metal diketonates, carbonyls, metallocenes, olefin complexes containing 2 to 20 carbon atoms, acetylene complexes, alkyl or arylphosphine complexes, and carboxylates containing 1 to 20 carbon atoms. Specific examples of these include platinum acetylacetonate, tris(acetylacetonate)rhodium(), triiodoiridium()tricarbonyl, π-cyclopentadienylrhenium()tricarbonyl, ruthenocene, π-cyclopentadi enyl osmium ()
Dicarbonyl dimer, dichloro(ethylene)palladium() dimer, π-cyclopentadienyl(ethylene)rhodium(), diphenylacetylene bis(triphenylphosphino)platinum(O), bromomethylbis(triethylphosphino) ) palladium (), tetrakis(triphenylphosphino)palladium (O), chlorocarbonylbis(triphenylphosphino)iridium (), palladium acetate and palladium naphthenate. Feedstocks cracked using the catalyst of the present invention include conventional hydrocarbon feedstocks such as naphtha, gas oil, light and heavy distillate oils, residual oils, and the like. Referring to FIG. 1, which illustrates a FOC device as a means of introducing the aforementioned decomposable metal compounds into the device, the decomposable metals may be introduced into the regenerator suspended in an air supply 46; may be introduced into the stream which is introduced into the stripping section of the reactor via a It may be introduced into the fluidized bed 22; it may be introduced into the upper part of the riser conversion zone 4; it may be introduced into the cyclone separator 32;
It may be introduced into the date preg 34; the catalyst bed 4
4; suspended catalyst particles 48; or diplegs 60, 62, 64, 66, etc. within enclosure 42. Among these, a preferred method is to directly inject it into the high-density bed of the regenerator 44. We have explained how to introduce decomposable metal compounds using FOC (fluid catalytic cracking) equipment, but there are many similar introduction points for moving bed systems. Alternatively, if the "vortex" regenerator of Figure 1 is replaced by a riser regenerator (described in more detail below), the decomposable metal compound may be introduced into the riser itself; It may be introduced; the regenerated catalyst may be added to the circulating conduit; it may also be introduced at a position corresponding to that shown in FIG. Compared to the catalysts conventionally used to combust CO in regenerators, the trace metal compound catalysts used in the present invention affect the overall catalytic cracking process to different extents and in different ways.
This produces different results compared to not burning CO catalytically. Both nickel and vanadium are known to precipitate from hydrocarbon feedstocks onto cracking catalysts and oxidize carbon monoxide. However, these substances are known to act as catalyst poisons. It should be noted here that the purpose of catalytic cracking is to increase the yield of gasoline and other low boiling fractions from the total crude oil. Although catalyst components such as nickel or vanadium are active for the desired purpose, such as catalytically oxidizing CO, their toxicity reduces the yield of gasoline from the overall system. It means putting it away. In the case of nickel and vanadium and other transition metals such as manganese and/or chromium, the amount of coke formed during cracking in the cyclic catalytic cracking process increases considerably. As the amount of coke produced increases in this way,
Even if the amount of CO catalytically burned increases, the amount of carbon distilled on the regenerated catalyst will increase. When the amount of residual carbon increases, the catalyst activity decreases and the gasoline selectivity of the cracking component deteriorates. On the contrary, very small amounts of the CO oxidation catalyst of the present invention reduce the amount of coke formed on the cracking catalyst and increase the gasoline selectivity. When considering thermal (non-catalytic) oxidation of CO, much higher temperatures are required to initiate and maintain non-catalytic CO oxidation than when a catalyst is present. Zeolite cracking catalysts are adversely affected by exposure to high temperatures such as those encountered during thermal (non-catalytic) combustion of CO. Therefore, non-catalytic combustion of CO in a regenerator of a circulating cracking system without addition of hydrogen reduces the production of gatsulin. In endothermic cyclic catalytic cracking without hydrogen addition combined with a conventional catalyst rapid cyclic regeneration process (coke is burned off), the regenerator is operated in one of several general configurations. 1st
The regenerator in the FCC type of operation shown in the figure uses a dense fluidized bed of catalyst into which cooled coke deposited catalyst is introduced from the cracking reaction zone and regenerated from the same fluidized bed. The heated catalyst is removed and sent to the feed to the cracking reaction zone. Usually the temperature of the lean bed in such regenerators is higher than that of the dense bed, sometimes 56
The temperature is higher than ℃ (100〓). The flue gas may also be at a higher temperature. One significant advantage of using a platinum group metal modified catalyst in conjunction with increasing the amount of oxygen introduced into the regeneration zone in accordance with the present invention is the tendency to combust carbon monoxide in the dense phase rather than in the dilute phase. There is. The temperature difference between the two phases is thereby reduced. The temperature of the dilute phase decreases significantly, while the temperature of the dense phase increases only slowly. Due to this
The additional heat generated by the combustion of the CO can be imparted to a significant extent to the catalyst which is returned to the cracking zone. In current commercially available FCC devices operating using conventional catalysts, the conversion of CO is performed thermally rather than catalytically. However, there are various problems in the actual operation of these devices. These problems are overcome by using the catalyst of the present invention. pt, pd, Rh, Ru, Ir, Os
There are several advantages when operating these devices using catalysts containing suitably low concentrations (usually less than 10 ppm) of one or more metals selected from Re and Re. The value of ΔT decreases. That is, the temperature of the dense bed increases and the temperature of the dilute phase, cyclone and exhaust gas decreases rapidly. More of the heat of the system is thereby retained by the dense bed used in the reactor. If the temperature of the dense bed is high, the circulation rate of the catalyst will need to be reduced to provide the same amount of heat to the reactor. Slower circulation of the catalyst means less wear on the catalyst particles, fewer particles escaping with the regeneration gas, and less catalyst replenishment required to maintain a given level of activity.
The higher the temperature of the dense bed, the lower the amount of residual carbon on the catalyst that is returned to the reactor. The smaller the amount of residual carbon, the higher the catalyst activity. Slower catalyst circulation rates and lower amounts of residual coke reduce feed-based coke production, correspondingly increasing recoverable product and improving selectivity. When using the catalyst of the present invention, there is no need to inject steam to reduce the temperature of the cyclone. There is also no need to inject torch oil to increase the temperature of the dense bed to maintain thermal conversion of CO. Apart from the cost of steam and torch oil, adjusting these reduces catalyst activity and makes the process difficult to control.
Yet another advantage of the reduced catalyst circulation rate is less corrosion inside the equipment. The rate of circulation of the catalyst can also be reduced by preheating the feed to the cracking device, but the efficiency of the transfer of energy to the reactor in the form of heat is such that the heat is generated directly in the catalyst bed. The case is bigger. In fluidized cracking equipment and moving beds,
In some cases, the amount of coke deposited on the catalyst during the cracking cycle is insufficient and combustion of the coke does not generate sufficient heat. In such cases, the regenerator temperature may be too low to effectively reduce residual carbon to the desired level (eg, below 0.2% by weight). Furthermore, these units do not allow the use of newer, highly selective cracking catalysts that produce more expensive liquid products at the expense of coke. This is because these catalysts are more difficult to regenerate. When using the catalyst of the invention, sufficient additional heat is generated by the oxidation of carbon monoxide to improve selectivity. Another type of regenerator has a dense fluidized catalyst bed in the lower part to which the cooled coke deposited catalyst is added from the cracking zone, and a dispersed dilute phase in the upper part to which all the catalyst from the dense phase is added. rushes in. A portion of the hot regenerated catalyst from the upper lean phase is recycled to the lower dense bed to maintain the temperature of the dense bed at least high enough to initiate coke combustion. In this configuration, substantially all of the regenerated catalyst returned to the cracking zone is removed from the upper dispersed phase and little comes directly from the lower dense bed. In addition to providing sufficient oxygen to the regenerator to support the combustion of carbon monoxide, the use of a platinum group metal modified cracking catalyst increases the temperature of the dense bed and increases the temperature of the dense bed. The upper coke residue is reduced and the need to circulate hot catalyst from the upper lean phase to the lower dense phase is reduced or eliminated. In the moving bed cyclic catalytic cracking described above for TCC, the coke-deposited catalyst is passed from the cracking zone to a regeneration zone, sometimes called a kiln. The kiln itself has an upper section and a lower section. An oxygen-containing gas, preferably air, is fed between the two zones, while a coke deposited catalyst is fed to the top of the two zones. The air flows countercurrently in the upper zone with the coke-deposited catalyst, removing a portion of the coke by combustion;
It produces a flue gas consisting of carbon oxides containing significant amounts of carbon monoxide. The partially coke-free catalyst is sent from the upper section cocurrently with a portion of the feed air to the lower section where coke deposits are further removed by combustion and a flue gas consisting of carbon oxides is produced. When using a catalyst containing a platinum group metal as described herein and introducing sufficient oxygen into the kiln,
Some changes are observed in the carbon dioxide/carbon monoxide ratio in the flue gas from the countercurrent upper regeneration zone. However, under these same conditions the flue gas from the downflow lower regeneration zone contains substantially no carbon monoxide and is substantially all oxidized to carbon dioxide. The regenerated catalyst leaving the kiln is much hotter than it would be if it were not modified with the platinum group metal of the present invention, and the overall flue gas, which is the combined flue gas of the upper and lower kilns, has less carbon monoxide. . According to one embodiment of the invention, the platinum group metal can be incorporated into the cracking catalyst during its preparation. Alternatively, a platinum group metal decomposable compound may be brought into contact with the cracking catalyst being used in the cyclic cracking process. For example, in the TCC process, the platinum group metal decomposable compound may be applied directly to the cracking catalyst with coke deposits between the cracking reaction zone and the regeneration kiln zone. This type of operation, which provides sufficient air, combusts at least a portion of the carbon monoxide produced by burning coke in the upper countercurrent regeneration zone and converts it to carbon dioxide. Reduces the amount of carbon monoxide in the flue gas from the regeneration area. In this regard, it should be understood that there is competition for available oxygen between coke and carbon monoxide, especially in the upper regeneration zone. Therefore, it is difficult to burn CO with high efficiency in the upper region where the temperature is relatively low and the amount of coke is large. One embodiment of the present invention that tends to enhance the usefulness of cracking catalysts modified by the addition of trace amounts of platinum group metals, particularly in moving bed type cracking, is to recirculate a small amount of regenerated catalyst from the kiln outlet to the kiln inlet. It is. The amount to be recirculated is approx.
It may be up to 10% by weight or more.
Since this operation of recycling the catalyst increases the fixed charge of catalyst required, it is appropriate to keep the amount recycled to a minimum. This operation makes the regenerated catalyst hotter and cleaner and reduces the amount of carbon monoxide in the flue gas. The embodiment of the present invention for a moving bed, such as a TCC cracking device, using a platinum group metal modified cracking catalyst differs slightly from conventional flue gas exhaust mechanisms. In conventional operation, flue gas from the lower kiln is mixed with flue gas from the upper kiln, and the mixture is discharged. In contrast,
In the present invention, the flue gas from the upper kiln containing a significant amount of carbon monoxide is fed to the regeneration zone of the lower kiln together with the feed air. This allows the carbon monoxide in the upper flue gas to come into contact with the partially or fully regenerated platinum group metal-containing catalyst and excess air, which causes the carbon monoxide to be combusted and Much more is converted to carbon dioxide. The entire cycle of cracking is operated by continuously regenerating the downwardly flowing catalyst and then lifting the regenerated catalyst using compressed air or mechanically from the bottom of the regenerator kiln to the top of the cracking reactor. This is a conventional procedure in moving bed contact cracking equipment. In some cases compressed air is used to raise the catalyst, and in some cases a combination of steam and flue gas is used. When trace amounts of platinum group metals are incorporated into the cracking catalyst, carbon monoxide is significantly reduced or completely removed from the flue gas. In the present invention, the hot regeneration gas is lifted with the flue gas and air mixture as slowly as practical. The platinum group metal on the hot regenerated cracking catalyst catalyzes the combustion of carbon monoxide in the riser. This not only cleans the exhausted flue gases, but also heats the regenerated catalyst further, making its catalytic action in hydrocarbon cracking reactions more efficient. The oil fed to the process of the present invention is primarily about 343
A petroleum fraction, commonly known as gas oil, having a boiling point in the temperature range of ~538°C (approximately 650-1000°C), sometimes supplemented with coker gas oil, vacuum distillation column overhead oil, etc. These oils are generally substantially free of metal contaminants. Raw materials (fresh raw materials consisting of one or more oils) are approx.
The feedstock is cracked in a reactor in a reaction zone maintained at 427-649°C (approximately 800-1200〓) and at approximately 1-5 atmospheres, and the typical residence time of the feedstock is approximately It is 1 to 10 seconds. The residence time of the catalyst is about 1-15 seconds. Since the feedstock contains trace amounts of metals, primarily nickel and vanadium, an amount of metal accumulates that is the difference between the amount introduced with the fresh feedstock and the amount lost through removal and loss of catalyst. A constant charge of circulating catalyst that has been used for some time and has been replenished with nickel and vanadium is referred to as an "equilibrium catalyst". Equilibrium catalysts typically contain about 200 to 600 ppm nickel equivalent metal. Here, "nickel equivalent" is defined as follows: ppm nickel equivalent = ppm nickel + 0.25 ppm vanadium As mentioned above, in a preferred embodiment of the present invention, the circulating cracking catalyst is taken out as a side stream and the boiling point is The metal compound is deposited on the catalyst by catalytic impregnation in the contact area with a solution of the combustion promoting metal dissolved in a solvent in the range of about 60-316°C (about 140-600°C). Before or during this catalytic impregnation operation, the side stream is cooled to a temperature below about 600°C. The side stream is then returned to the circulating catalyst. The sidestream can be taken from various parts of the catalyst zone, or is preferably taken from the reaction zone or the coked catalyst conduit to form a coked catalyst sidestream. Preferably, at least a portion of the catalytic impregnation operation is carried out at a temperature near or above the boiling point of the solvent, as described below. In order to achieve intimate catalyst impregnation with the combustion promoting metal, it is preferred that the catalyst is fluidized during contact in the contact zone. Useful solvents include water and liquid organic compounds having boiling points in the aforementioned ranges. According to the method of the present invention, the effectiveness of the combustion-promoting metal in promoting the combustion of carbon monoxide is increased, and the loss of some of the combustion-promoting metal and the precipitation of the metal at locations other than on the catalyst are avoided. Although the effectiveness of a particular metal may vary depending on the method by which it is introduced into the catalyst, Figure 3 shows a series of combustion-promoting metals having various combustion-promoting metals conventionally deposited on the catalyst during catalyst manufacture. Figure 2 shows relative oxidation activity for cracking catalysts. Preference is given to using platinum for the purposes of the invention. Metal compounds useful in the present invention include metal halides (preferably chlorides), nitrates, amine halides, oxides, sulfates, phosphates and other water-soluble inorganic salts, and also those having 1 to 5 carbon atoms. metal carboxylates or alcoholates.
Specific examples include palladium chloride, platinum hydrochloride, tetraamine platinum () dichloride, ruthenium pentaamine chloride, osmium chloride perrhenate, dioxopis (ethylenediamine) rhenium () chloride, and rhodium chloride. Metal-organic compounds of the aforementioned metals can also be used, such as metal diketonates, carbonyl compounds, metallocenes, olefin complexes with 2 to 20 carbon atoms, alkyl or arylphosphine complexes and carboxylic acid salts with 1 to 20 carbon atoms. There is. Specific examples of these include platinum acetylacetonate, tris(acetylacetonate)rhodium(), triiodoiridium()tricarbonyl, π-cyclopentadienylrhenium()tricarbonyl, ruthenoline, π-cyclopentadi enyl osmium () dicarbonyl dimer, dichloro(ethylene) palladium () dimer, (π-cyclopentadienyl) (ethylene) rhodium (), diphenylacetylene bis (triphenyl phosphino) platinum (O), bromomethyl Examples include bis(triethylphosphino)palladium (), tetrakis(triphenyl)palladium (O), chlorocarbonylbis(triphenylphosphino)iridium (), palladium acetate, and palladium naphthenate. It is a feature of the invention that relatively simple and inexpensive compounds such as hydrochloroplatinic acid or tetraammineplatinum dichloride can be used. Solvents useful in the method of the invention include water, polar organic solvents, liquid hydrocarbons, and generally any organic or inorganic fluid that is a solvent for the aforementioned metal compounds. Typical examples include methanol, ethanol, isopropanol, t-
Alcohols such as butanol, 2-ethylhexanol, octanol, glycerol and ethylene glycol; esters such as ethyl acetate, butyl acetate, amyl acetate; diethylene glycol, diisopropyl ether, di-n-butyl ether, cellosolve, methyl cellosolve, butyl cellosolve, etc. ethers; hydrocarbons such as octane, nonane, decane, dodecane, hexadecane, benzene, toluene, xylene, cumene, and mixtures thereof. Mixtures of solvents are particularly effective, as will be explained in more detail below. Representative examples of such mixtures include, but are not limited to, water-ethylene glycol mixtures, benzene-cumene mixtures, and t-butyl alcohol-water mixtures. Preferred solvents and mixtures thereof useful in the present invention are from about 60 to 316°C (approximately
It has a boiling point of 140-600〓). In the process of the present invention, it is necessary to cool the hot circulating cracking catalyst sidestream, which is at a temperature substantially above 316°C (600°), to a temperature below 316°C (600°). The method of the present invention is effective because it avoids premature decomposition of the combustion-promoting metal compound, ie, decomposition of the combustion-promoting metal compound before it comes into contact with the catalyst and is sufficiently dispersed on its surface. Therefore, the exact temperature at which the solution of the combustion-promoting metal compound contacts the side stream of the cracking catalyst in order to maximize the effectiveness of the combustion-promoting metal compound will depend on the thermal stability of the metal compound used and the type of solvent used. and possibly also on the nature of the cracking catalyst itself. For example, as described below, under a contact area pressure of approximately 2.1 Kg/cm ² meter pressure (approximately 30 psig), the boiling point of water is approximately 135 °C (approximately 275 °C).
A significant effect was observed in the case of tetraammineplatinum dichloride using water as a solvent at temperatures of 0.05% and above. It is generally preferred to carry out the contacting step under conditions such that at least a portion of the solvent wets the catalyst. Prior to the contacting step, the side stream of the cracking catalyst may be indirectly cooled by cooling means using air or other heat transfer fluid to remove heat through a physical barrier such as a pipe wall; Direct cooling may also be achieved by contacting the stream with an inert gas or water injected. A combination of direct cooling means and open cooling means may be used. When a side stream of the cracking catalyst is contacted with a solution of a combustion-promoting metal compound, at least some direct cooling necessarily occurs, and this cooling is due to evaporation of the solvent. That is, a significant portion, if not all, of the desired cooling is achieved by simply diluting the solution of the combustion-promoting metal compound with a substantial excess of solvent and injecting a large amount of the solution into the contact area. be done. Mixtures of different volatile solvents can also be advantageously used, such as mixtures of small amounts of glycerol and large amounts of water. In this case, the water acts as both a solvent and a cooling agent, and the less volatile glycerol helps to maintain the integrity of the combustion-promoting metal compound from decomposition until proper contact with the catalyst. The cooling effect of solvent evaporation is enhanced by using a solvent that decomposes endothermically on contact with the hot cracking catalyst. Examples of these solvents include alcohols such as t-butyl alcohol, which decomposes into isobutylene and water, and isopropyl alcohol, which decomposes into propylene and water. Such endothermically decomposing solvents may be used alone or in combination with other solvents. Mixtures of solvents having boiling points in the range of about 140-600°C are suitable. As used herein, "boiling range" can be applied to solvent mixtures or to single solvents, and refers to the temperature at which at least 95% of the solvent, ie, substantially all of the solvent, evaporates.
Furthermore, pressures in these boiling point ranges are, unless otherwise specified, pressures in the contact zone, i.e. approx.
0.7-3.5Kg/ ^cm2 meter pressure (approximately 10-50 psig). Although the catalyst side stream may be taken from any portion of the hot circulating cracking catalyst, it is preferred to use the coke-deposited catalyst side stream for purposes of the present invention. It is therefore preferable to take off a side stream from the reactor or from the conduit of the catalyst where the coke has deposited. When removing from the reactor, it is preferred to remove the catalyst from the stripper area to avoid problems caused by the presence of volatile hydrocarbons on the catalyst. That is, it is desirable that the coke deposited catalyst be substantially free of gas oil or conversion products when contacted with the combustion promoting metal solution. The removed side stream comes into contact with a solution of combustion promoting metal in the contact zone. The solution is introduced by a spray nozzle or other suitable device that facilitates close contact. It is desirable to keep the catalyst in a fluid state in the contact zone, so that the temperature remains uniform and the metal compound is well distributed over the catalyst. Evaporation of the solvent promotes fluidization. After impregnation, the side stream is returned and mixed with the hot circulating catalyst. Upon return to high temperatures, the metal compounds decompose into active forms of combustion promoters. Only trace amounts of the metal are present, but the nature of the metal in its active state is difficult to determine precisely, and we do not know whether it exists as an elemental metal, sulfide, oxide, or other form. . The combustion promoting metal applied to the catalyst by the method of the present invention may be applied to all the catalysts or only to some of the catalysts. Its concentration in the entire system must be sufficient to cause carbon monoxide to react with oxygen to carbon dioxide, and the conditions in the regenerator must be sufficient to support this combustion, e.g. It must have a high temperature and sufficient air. Moreover, it must not be present in such an amount that it adversely affects the cracking operation of the method of the invention. The upper limit of the content of combustion-promoting metals depends in part on the capacity of the cracking equipment, including auxiliary equipment and equipment for dissolving the downward flow products, with reference to the production output of the actual operation, and the upper limit of the content of platinum group metals The upper limit value must not exceed this ability. Furthermore, when considered in practice, each of the seven metals of the platinum group defined herein has a different effect on its intended use in the apparatus of the present invention. Therefore, these upper and lower limits for metals are comprehensive values that apply to all metals, and these values cannot necessarily be well applied to a specific metal. Thus, for example, a suitable upper limit for the total content of platinum group metals is approximately
100 ppm, which is clearly an appropriate upper limit for this genus, but this upper limit is too high for certain members of this genus. For example, in the case of platinum and iridium, about 10 ppm is a preferred upper limit. Therefore, all platinum group metals increase catalytic activity with concentration. In other words, the effect does not disappear in the range just above 50 ppm. This upper limit of 50 ppm is an amount that allows the least active metal of the platinum group metals described herein to have significant oxidation activity. For example, in Figure 3 of this specification, if we extrapolate the curve for osmium, which is the lowest active metal at a concentration of 50 ppm, it will be greater than 50.
An activity indicating the relative CO ₂ /CO ratio is obtained. An upper limit of 50 ppm for promoters (platinum group metals or rhenium) can also be shown from cracking reaction selectivity data. When the amount of promoter metal is more than 50 ppm, the selectivity of the dehydrogenation activity in the cracking reaction is significantly reduced. In industrial operations, many cracking devices are limited by the volume of gaseous product that can be captured and separated, so even small amounts of hydrogen in the product can significantly increase the gas volume. This poses a major operational problem. Table 1 shows the effects when the platinum content is 0.1 to 200 ppm. The dehydrogenation activity can be evaluated by the relative hydrogen coefficient defined as follows: Relative hydrogen coefficient = Hydrogen coefficient / (Hydrogen coefficient) = × 100 Hydrogen coefficient = Number of moles of hydrogen / Number of moles of (C ₁ + C ₂ ) ×
100 Base: without metal. Figure 4 shows the data in Table 1 in a semi-logarithmic chart. Table 1 and Figure 4 show that the relative hydrogen coefficient increases significantly when the platinum content exceeds 50 ppm. This has a severe negative impact on industrial operations.

【table】

TABLE FIGS. 5 and 6 show two different layouts of side streams and contact areas in the device of the invention. In both figures the catalyst area shown in FIG. 1 is represented by simple lines, and the same numbers have been used for the same parts as in FIG. In the sidestream and contact zone in FIG.
sent to. This regulating valve functions to regulate the flow rate of the side stream. The material passing through this valve is conduit 7
2 to a heat exchanger 73, which serves to cool the side stream. The cooled catalyst is passed through conduit 74 to vessel 75. Container 75 is equipped with a nozzle, spray head or other discharge device 78 operative to discharge a solution of combustion promoting metal compound supplied thereto by conduit 77. Conduit 79 feeds into container 75 and connects to discharge device 78 . This conduit 79
, which may be separate or in combination with conduit 77 , convey compressed air, steam, nitrogen, volatile solvent or other inert dispersion medium into vessel 75 to maintain the catalyst in a fluid state in contacting zone 75 . The contacted and cooled catalyst is sent by conduit 80 to the regenerator. In this way, the sidestream catalyst is returned to the circulating catalyst. In FIG. 5, the side stream is taken off from the conduit 36 leading from the stripping zone 24 shown in FIG. , or other hot circulating catalyst at any suitable convenient point. In FIG. 4, the side stream is returned to the circulating catalyst by conduit 80 and returned to the regenerator stream, but it may be returned to any part of the catalyst section, such as the regenerated catalyst conduit. Container 75 is preferably equipped with a temperature measuring device such as a thermocouple 76. FIG. 6 shows another example of the arrangement of the device of the present invention. In this arrangement, vessel 90 is connected to the stripping section of reactor 81 through conduit 91, with the stripping section and the contents of vessel 90 being in free communication through conduit 91. Conduits 77 and 7
9 and ejection device 78 represent the same parts as shown in FIG. Conduits 77 and 79 feed into a container 90, within which ejection device 78 is located. In this device, the fluidized catalyst is in stripper section 2
4 to vessel 90 where it is contacted with a solution of combustion promoting metal compounds and then returned to the stripper area through the same conduit. This container 90
(Contact area) may be attached to a regenerator or the like separately from the location shown. Any position may be used as long as the contents of the container 90 and the hot coked fluidized catalyst can freely communicate with each other. Although the present invention has been described in terms of a vortex regenerator, as shown in FIG. is equally applicable. According to the method of the invention, a solution of combustion-promoting metal compounds can be applied to both fresh and equilibrium catalysts. The combustion promoting metal may be applied to the catalyst during the reaction operation, or the metal may be precipitated in the catalyst manufacturing process and the catalyst may be used in the reaction. The method of the invention is used to regulate the combustion of carbon monoxide in a regenerator, said regulation adjusting the flow rate of the side stream, the pressure of the pump and the concentration of the solution of combustion-promoting metals depending on the composition of the flue gas. This is achieved by doing. The present invention will be explained in more detail by the following examples, but the present invention should not be limited thereto. All parts or percentages are by weight unless otherwise specified. Example 1 In this example and the examples below, continuous
An FCC pilot plant was used. The pilot plant consists of a regenerator, a riser reactor corresponding to 4 in FIG. 1 communicating with a stripping section corresponding to 24 in FIG. 1, and conduits corresponding to 6 and 36 in FIG. The equilibrium catalyst used in this and subsequent examples was taken from a commercially available catalytic cracking plant. The catalyst is a typical commercially available material of the faugiasite type that is ion-exchanged with rare earth elements, and this faugiasite is dispersed in a silica-alumina matrix. Its composition is SiO ₂ 61.3%, Al ₂ O ₃ 35.9%,
The contents were 2.77% Re ₂ O ₃ , 0.51% Na, 359 ppm nickel and 404 ppm vanadium. For purposes of the present invention a tubular vessel as shown in FIG. 6 is provided and connected to the dense bed of the regenerator. This tubular container had a volume of 25 ^cm3 . This tubular vessel is supplied with nitrogen to keep the catalyst in a fluid state within the vessel. Prior to contacting and impregnating the catalyst with combustion-promoting metal compounds, the pilot plant was charged with 3500 g of the aforementioned catalyst as a fixed amount of circulating catalyst and with a wide range of boiling point gases obtained from Mid-Continent crude oil as feedstock. It was operated using oil and the operating conditions were adjusted as follows. Reactor temperature 538℃ (1000〓) Stripper temperature 538℃ (1000〓) Regenerator temperature 677℃ (1250〓) Catalyst residence time in riser 7.0 seconds Oil zone residence time in riser 4.5 seconds Catalyst/oil weight ratio 6.0 A solution of 6 mg of metallic platinum as tetraammineplatinum dichloride in 250 ml of water was placed in a feed bottle. This solution is fed as a jet into the aforementioned tubular vessel containing the fluidized catalyst, the feed rate being such that the temperature in the contact area is approximately 177°C (approx.
350〓). Prior to introducing the solution, the temperature in the contact area was approximately 482°C (approximately 900°C). The adjusted feed rate was 66 ml/hour and the feed was stopped after 231 ml of solution had been fed into the contact area. Samples of the catalyst were taken every 30 minutes to determine the effectiveness of the catalyst in burning carbon monoxide. The results are shown in Table 2 below.

[Table] Example 2 The operation of Example 1 was repeated with a fresh feed of equilibrium catalyst, in this example obtained from Sour West Texas Crude instead of gas oil with a wide range of boiling points as the feedstock. Heavy vacuum gas oil was used. In this example, platinum 6 is used as tetraammineplatinum dichloride.
mg was dissolved in 180 ml of water. This solution was fed at a rate of 119 ml/hour, while the temperature in the contact zone was approximately room temperature. Catalyst samples removed from the stripper after 1 hour showed no increase in activity in promoting the combustion of CO. The impregnation continued for the next hour and 78 ml of the above solution was fed, by the end of which the temperature in the contact area was approximately 177°C.
(about 350〓). Test results on a sample of the catalyst removed after this two hour impregnation operation showed a CO ₂ /CO ratio of 6.3. Test results on the catalyst before the impregnation operation showed a CO ₂ /CO ratio of 2.7. The content of combustion promoting metals in this sample was 1.9 ppm. Example 3 In this example, a tubular vessel for a catalytic impregnation operation was installed in the stripping area of a pilot plant. The apparatus was fed with untreated equilibrium catalyst and Example 1
The heavy vacuum gas oil used in Example 2 was used as the raw material oil. A solution of 2 mg of platinum dissolved in 250 ml of water was fed at a rate of 90 ml/hour to contact the catalyst, consuming 135 ml of solution. The temperature in the contact area is initially about 204
℃ (approximately 400 〓), which dropped to 104 ℃ (220 〓) at the end of the catalytic impregnation operation. The platinum content of this catalyst sample was 0.31 ppm and the CO ₂ /CO ratio was 410 according to the test results. Example 4 The procedure of Example 3 was repeated with a fresh supply of equilibrium catalyst, but the flow rate of the contacting impregnating solution and the flow rate of the nitrogen were such that the temperature in the contact zone was between about 204 and about 316°C (about 400 and about 600°C).
The temperature was adjusted to maintain a temperature range of . The final catalyst sample had a platinum content of 0.29 ppm and carbon monoxide was completely burned out. i.e.
The CO ₂ /CO ratio was infinite.

[Brief explanation of the drawing]

FIG. 1 shows the catalyst section of a conventional fluid catalytic cracking device. 2...hydrocarbon raw material, 4...riser, 14,
32...Cyclone separator, 22...Catalyst bed, 2
4... Stripping area, 42... Regeneration area,
36... Conduit, 6... Stand pipe, 40...
Catalyst removal funnel FIG. 2 is a cross-sectional view of the catalyst section shown in FIG. 1 along line A--A. FIG. 3 shows the relative oxidation activity for cracking catalysts with various combustion promoting metals. FIG. 4 is a semi-logarithmic chart showing the relationship between platinum promoter content and relative hydrogen coefficient.
FIG. 5 shows one form of arrangement of side streams and contact areas in the device of the invention. 81... Reaction container, 71... Flow rate adjustment valve,
73... Heat exchanger, 75... Contact vessel, 76...
Temperature measuring device, 78...spray nozzle, FIG. 6 also shows one form of arrangement of side streams and contact areas in the device of the invention. 90... Contact container, 91... Conduit.

Claims (1)

[Claims] 1. A method comprising passing a catalyst that has been in contact with a raw material in a reactor under cracking conditions without adding hydrogen to an external circuit equipped with a regenerator and returning the catalyst in a regenerated form to the reactor; The moving population of is 0.01 ~
A catalyst regeneration cycle catalytic cracking process comprising 50 ppm of a platinum group metal or rhenium, wherein said platinum group metal or rhenium is applied to said catalyst while said catalyst is passing through said circuit. Regenerative circulation contact cracking method. 2. A process according to claim 1, wherein the platinum group metal or rhenium is applied to the catalyst as a compound that can be decomposed under the operating conditions. 3. The method of claim 1, wherein the platinum group metal or rhenium is applied to the catalyst as a colloidal suspension in a suitable medium or as a dispersion on a refractory oxide matrix of colloidal particle size. 4. A process according to claim 1, wherein the platinum group metal or rhenium is applied to the catalyst as an emulsion of the metal compound in a liquid or as a vapor of the metal compound in a gaseous carrier. 5. Spent catalyst is periodically removed from the catalyst transfer mass and replaced with fresh catalyst in a known manner, and the metal is applied to the catalyst at intervals such as to keep its concentration substantially constant. The method described in any one of paragraphs to paragraphs 4 to 4. 6. The method according to any one of claims 1 to 5, wherein the metal concentration is 0.5 to 10 ppm. 7. A method according to any one of claims 1 to 6, wherein the metal is applied to the catalyst in the regenerator. 8. A method according to any one of claims 1 to 6, wherein the metal is subjected to the catalyst while it is being sent from the reactor to the regenerator. 9. The method of claim 8, wherein the catalyst is unstripped. 10 Claims 1 to 6 applied to the catalyst while the metal is being sent from the regenerator to the reactor
The method described in any one of the preceding paragraphs. 11. A method according to any one of claims 1 to 6, which is applied to the catalyst while the metal is flowing in a side stream. 12. The method of claim 11, wherein the side stream is a stream removed from the catalyst stripping zone. 13. The method of claim 11, wherein the side stream is a stream taken from the coke deposited catalyst conduit. 14. The method of any one of claims 11 to 13, wherein the side stream is from a single closed vessel. 15. The method of claim 14, wherein the vessel is open to the reactor, regenerator, coke deposited catalyst conduit or regenerated catalyst standpipe. 16. The method according to any one of claims 11 to 15, wherein the catalyst in the side stream is fluidized. 17 60-316℃ (140-600℃) under the prevailing pressure of the metal
The method according to any one of claims 11 to 16, wherein the method is carried out as a solution in a boiling solvent. 18. The process of claim 17, wherein the catalyst in the side stream is at a temperature below 316°C (600°C). 19. The method according to claim 17 or 18, wherein the solvent is water. 20. Any one of claims 17 to 19, wherein the amount of solution used is sufficient to cool the side stream to the boiling range of the solvent at the prevailing pressure.
The method described in section. 21. The method according to any one of claims 17 to 20, wherein the solvent is an organic compound that decomposes endothermically on contact with a high temperature cracking catalyst. 22. The method of claim 1, wherein the metal is applied to the catalyst by mixing the metal and refractory support composite with the catalyst. 23. The method of claim 22, wherein the support is an inorganic oxide such as alumina, silica-alumina or clay. 24. The method of claim 22 or 23, wherein the support is a particulate material having substantially the same size as the catalyst.