PL112833B1 - Cyclic process for fluid catalytic cracking - Google Patents

Description

The present invention relates to a cyclic fluid catalytic cracking process suitable for use with sulfur-containing hydrocarbon feedstocks. This process is characterized by significantly reduced emission of sulfur oxides in the exhaust gas from the catalyst regeneration unit. A cracking catalyst which has become relatively inactive due to the deposition of carbon deposits, commonly known as "coke", which occurs during the cracking of hydrocarbons in the reaction zone, it is continuously removed from this zone. The spent catalyst is discharged from the reaction zone into a desorption zone, where evaporable carbon deposits, i.e. hydrocarbons, evaporate from the catalyst. The catalyst is in turn discharged into the regge zone. Generation, in which it is restored to remove non-evaporative deposits by burning the coke with an oxygen-containing gas, resulting in the formation of carbon monoxide and carbon dioxide The hot regenerated catalyst is then continuously returned to the reactor to repeat the cycle. The problem of incomplete combustion of carbon monoxide at d is associated with catalytic cracking carbon dioxide in the regeneration zone, whereby a significant amount of carbon oxygen remains in the exhaust gas of the regeneration zone. Apart from the fact that the discharge of carbon monoxide into the atmosphere is undesirable, this compound tends to react with the residual oxygen contained in the exhaust gas from the regeneration zone, causing combustion in the exhaust pipes and ducts to lead to them In addition, when the catalytic cracker is fed with raw materials with a high sulfur content, i.e. petroleum hydrocarbon fractions containing organic sulfur compounds, sulfur is part of the coke deposited on the catalyst. During the regeneration of the coked, deactivated catalyst, the coke burns off its surface, and during the burnout process, sulfur is converted to sulfur dioxide. ki and, to a small extent, sulfur trioxide, which compounds are part of the flue gas stream flowing out of the regeneration zone. When cracking raw material with a high sulfur content, sulfur oxides emissions often reach around 1200 parts per million. In the case of carbon monoxide and solids emissions, pollution standards have been established, and it is expected that such standards will soon be developed for emissions of other compounds , for example sulfur oxides, especially sulfur dioxide. Consequently, considerable importance is attached to reducing the level of emissions of the various combustion products and solid particles in the gaseous streams flowing from the regeneration zones connected to the oil crackers. It is imperative that the chosen method of reducing these emissions should work effectively without It is also necessary that the chosen method does not create an undesirable emission of other samples * 112 833 \ 112: 3, e.g. it does not increase the emission of solid particles or increase the operating costs. With these requirements in mind, a highly desirable way to reduce sulfur oxide emissions in petroleum crackers is to use a cracking catalyst modified to reduce sulfur oxide emissions while maintaining activity, durability and wear resistance. under normal cracking conditions, in any type of cracker, the use of metals is generally avoided in the case of cracking catalysts, and it is believed that the use of metal-containing raw materials in the presence of cracking catalysts is problematic, however, South African Patent No. 7924/72 and its later US-issued counterpart No. 3,909,392 (1975), which will be discussed in more detail later, describe the simultaneous use of cracking catalysts and burn-up catalysts or promoters in a regeneration zone that is in the burn zone. The spanking contains a metal rod, sulfur or sieve. These descriptions also give fluidizable metal compounds, in particular powdered transition metal oxides, e.g., ferric oxide, manganese oxide and rare earth oxides, which compounds are added in the catalyst charge or are found in the catalyst charge. only in a regenerator. Belgian Patent No. 826,266 (1975) describes a method very similar to the method described in US Patent No. 826,266 (1975). US Am. No. 3,909,392, which is based on the physical combination of a cracking catalyst with a carbon monoxide oxidation catalyst which is a metal with an atomic number of at least 20. As suitable promoters for the oxidation reaction are metals from groups of copper and zinc metals and metals from groups III to VIII of the Periodic Table, especially platinum, palladium, rhodium, molybdenum, tungsten, copper, chromium, nickel, manganese, cobalt, vanadium, iron, cerium, ytterbium and uranium In U.S. Patent No. United States, Am. No. 3,808,121 describes a catalyst regeneration process carried out in the presence of a carbon monoxide oxidation catalyst, which catalyst remains in the regeneration zone. A cracking catalyst containing less than 100 parts per million (metal and total catalyst) is known. a compound of at least one metal belonging to the group consisting of period 5 and 6 metals of the Periodic System Group VIII, with rhenium and its compounds particularly effective in reducing the content of carbon monoxide in flue gases from cracking catalysts. Also known is a cracking catalyst of the molecular sieve type obtained in the sodium form and undergoing ion exchange into the ammonium form and then saturated with rare earth metals. In the case of sulfur oxide emission, many methods of treating the flue gases have been used, e.g. scrubbing or washing. , chemical absorption, neutralization, and chemical reactions or conversions, but all these methods of sulfur oxide removal require large and expensive ancillary equipment, resulting in increased operating and investment costs. US Am. No. 3,699,037 consists in adding during the cracking cycle - at least a stoichiometric amount of a compound of calcium or magnesium in relation to the amount of sulfur deposited on the catalyst. The task of the added substance is to react with sulfur oxides, and then in a strong state When finely divided, it leaves the cracking cycle as solid particles in the flue gas stream from the regeneration zone. Continuous addition of such a material significantly increases the operating costs. Similarly, in US Pat. US Am. Nos. 3,030,300 (1962) and 3,030,314 (1962) describe a catalytic cracking process in which one or more compounds of boron, alkali metals and alkaline earth metals are added continuously during the cracking cycle in a moving bed. obtaining a catalyst with increased resistance to tearing under the influence of impact and to surface abrasion. This catalyst consists of silicon catalyst particles having a microporous, catalytically active core coated with an adherent protective coating of glaze containing silica and one or more compounds of boron, alkali metals or alkaline earth metals. United States No. 3,835,031 (1974) describes a fluidized bed cyclic catalytic cracking process with reduced emission of sulfur oxides in the flue gas from a regenerator. This method uses a catalyst containing a silicon dioxide-alumina system in the base material, impregnated with one or more alkaline earth metal oxides, a molecular sieve. United States No. 3,388,077 (J968); 3,409,390 (1968) and 3,849,343 (1974) describe a method for increasing the conversion efficiency of a harmful exhaust gas stream containing carbon monoxide and sulfur oxides. The method consists in contacting the stream with a catalyst composition consisting of a porous, refractory carrier, a catalytically active metallic component, for example a metal of the nickel group, and an alkaline earth metal selected from the group consisting of calcium, barium and strontium. So far, no one has discovered the method according to the present invention. The method according to the invention is a cyclic fluid catalytic cracking process which allows the emission of sulfur oxides in the exhaust gas from the regeneration zone to be reduced. According to the invention, in order to reduce the emission of harmful gases to the atmosphere, the cyclic process of fluidized catalytic cracking of a hydrocarbon feed containing organic sulfur compounds is carried out in such a way that the feed is cracked in the reaction zone using molecular sieve-type cracking catalyst particles, where the catalyst particles are in the fluidized state and then from the leaving stream the reaction zone is separated from the catalyst particles inactivated by the sulfur-containing carbon deposits and passed to a stripping zone, where the deactivated catalyst contacts the strip-gas to remove volatile deposits from the catalyst. The desorbed catalyst particles are separated from the stream leaving the stripping zone, passed to the regeneration zone and regenerated by burning the desorbed catalyst particles v non-desorbable sulfur-containing carbon deposits with oxygen-containing gas, and the regenerated particles are separated from the cascade. of the stream leaving the regeneration zone and returned to the reaction zone, (112 833 5 according to the invention, during the fluidized catalytic stripping process, the above cracking catalyst is added to the above cracking catalyst with fluidizable particles containing a metallic reagent, to obtain a mixture of particles containing from about 10 to about 99.9975% by weight of a molecular sieve cracking catalyst. At least one metal element is used as the metallic reactant, either in the free state or in the form of a compound of the group consisting of magnesium, calcium, strontium, and barium . This reagent is in a mixture of particles. It is used in an amount sufficient to cause the absorption of at least about 50% of the sulfur oxides resulting from the burning of sulfur-containing carbon deposits in the regeneration zone. Cracking of the raw material is carried out at a temperature of about 455-650 ° C, from the leaving quench the reaction zone is separated from the catalyst particles, inactivated by the sulfur-containing carbon deposits, and the particle mixtures are stripped at a temperature of about 455-650 ° C, the volatile deposits are stripped off using a water vapor stripper gas equivalent to the weight ratio of the vapor water to the cracking catalyst 0.00Q5-0.025. The desorbed mixed particle is regenerated at a temperature of about 560 ° -79 ° C, and at least about 50% of the sulfur oxides produced by combustion in the regeneration zone of sulfur-containing carbonaceous deposits are absorbed on the mixture of particles. The particles containing the absorbed sulfur oxides are led from the regeneration zone to the reaction zone, whereupon sulfur oxides are withdrawn from the stripping zone in the form of a sulfur-containing gas, while from the regeneration zone a gas stream containing molecular oxygen and a small amount of sulfur oxides is withdrawn. The method according to the invention makes it possible to carry out substantially complete combustion of the carbon monoxide in the regeneration zone and to absorb the heat generated during this combustion by means of solid particles which are returned to the reaction zone and the desorption zone before returning to the regeneration zone. These solid particles consist of a cracking catalyst of the molecular sieve type and a metal reagent, and may also contain an amorphous cracking catalyst and solids essentially inert to the hydrocarbon cracking process. The metal reagent may be introduced into the molecular sieve cracking catalyst, to an amorphous cracking catalyst and to a substantially inert solid. This introduction may be made before, during or after the introduction of the substrate in a given cycle of the cracking process. The cycle conditions for the cracking process are chosen such that a stable metal and sulfur compound is formed in the solid particles in the regeneration zone, and the sulfur-containing gas leaves the desorption zone. In the case of reducing catalysts. the emission of sulfur oxides in the exhaust gas from the regeneration zone during the fluid cracking operation, it is important that the catalysts not only be able to perform the said function in the initial period, but also that they perform these functions satisfactorily over extended periods of time. Therefore, in the work, the charge of these catalysts should take into account the characteristics of their activity and stability. 6 Activity is a measure of a catalyst's ability to reduce sulfur oxide emissions in the exhaust gas from a regeneration zone under a certain regime, where the regime is taken to mean the conditions used, i.e. temperature, pressure, contact time, etc. The stability of a catalyst is a measure of its ability to retain characteristics of activity in a given period of time. Stability is related to the rate of change of activity parameters over time, the lower rate of these changes means that the catalyst is more stable. The stability of the catalyst should be such that the activity characteristics can be maintained over an extended period of time. These basic characteristics can be achieved more easily during the cracking cycle: an effective sulfur reducing agent, i.e. a metal reagent in the present invention. It should be introduced into the solid particles in situ rather than into the cracking catalyst. of molecular sieve type during the preparation of this catalyst. 20 It has been found that the introduction of a metallic reagent during the cracking process cycle results in a greater reduction in the emission of sulfur oxide in the exhaust gas from the regeneration zone than its introduction by combining with a sieve-type cracking catalyst. Molecular tyrla during catalyst preparation. Addition of the metallic reagent during the cycle of the cracking process is also advantageous in that there is then a better possibility to control any harmful effect of the metallic reagent on the cracking reactions, since the rate of addition of the reagent and / or its amount can be varied. previously with a molecular sieve type cracking catalyst, it may be lost due to the fragmentation that occurs during abrasion of the catalysts. The addition of a metallic reagent during the cracking cycle cycle and its incorporation into the solid particles in situ allows the required amount of this reagent to be maintained at the desired level. It is an object of the present invention to improve a fluidized catalytic cracking cyclic process, in which the hydrocarbon feedstock containing organic sulfur compounds is cracked in a reaction zone under fluidization conditions. in the presence of homogeneous or heterogeneous solid particles forming the fluidized bed. These particles are regenerable and contain a metallic reagent and a molecular sieve-type cracking catalyst consisting of the base substance of the cracking catalyst and crystalline aluminosilicate dispersed therein. The cracking catalyst is inactivated in the reaction zone by sulfur-containing carbon deposits. The solid particles in the fluidized state are separated from the cracked hydrocarbons leaving the reaction zone and led to a desorption zone where evaporating carbon deposits are evaporated from the deactivated cracking catalyst upon contact with the stripper gas. The solid particles in the fluidized state are then separated from the gases leaving the desorption zone and led to a regeneration zone where the desorbed deactivated cracking catalyst is regenerated to render it highly active. Burnout of the non-evaporative sulfur-containing fs-containing carbon deposits upon contact with an oxygen-containing gas stream7. The result is carbon monoxide, carbon dioxide and sulfur oxides, which react with a metallic reagent to form a metal and sulfur compound in solid particles. The solid particles in the fluidized state containing the regenerated catalyst are separated from the flue gas leaving the regeneration zone and returned to the reaction zone. A preferred method of the invention consists in introducing a liquid substance containing metal in a metal reagent during the cracking cycle and introducing this metal reagent. * to solid particles over the cycle, the waste gas used contains water vapor3. the regeneration of the desorbed deactivated cracking catalyst takes place in the regeneration temperature range where the metal and sulfur compound is stable in solid particles, and by supplying the regeneration zone to the regeneration zone with an oxygen-containing regeneration gas stream in sufficient quantity, the flue gases leaving the regeneration zone contain oxygen. Molecular. The hydrocarbon feedstock used in the process may contain about 0.2-6% by weight of sulfur in the form of organic sulfur compounds. It is preferred that the feed contains about 0.5-5% by weight of sulfur, and more preferably about 1-4% by weight of sulfur in the form of organic sulfur compounds. The cracking catalyst base of the molecular sieve cracking catalyst is preferably a combination of at least two substances from the group consisting of silicon dioxide, alumina, thorium dioxide, boron trioxide, and more preferably silicon dioxide-alumina. Such cracking catalyst base material preferably contains about 10-65 and more preferably about 25-60% by weight of alumina, preferably about 35-90, and more preferably about 35-70% by weight of silicon dioxide and preferably about 0.5-50 and more preferably about 5-50% by weight of crystalline Preferably, the molecular sieve cracking catalyst is from about 1.0 to about 99.9975, more preferably about 30-99.99, and most preferably about 90-99.9% by weight of the The metallic reactant consists of at least one unbound or bound metallic element of the Group, magnesium, strontium, calcium and barium. Accordingly, the metallic reagent may be selected from the group consisting of magnesium, calcium, strontium, barium, 1 compounds of these elements, and mixtures thereof. It is more preferred that the metallic reagent is selected from the group consisting of magnesium and calcium. that the oxides or oxides of the metallic element or elements present in the metallic reagent are responsible for the absorption of the sulfur oxides in the regeneration zone. In this connection, it is preferable that the metallic element or elements of the metallic reactant be introduced in the form of an oxide or oxides during the cracking cycle. However, it is sufficient for the process described herein to use one or more metallic elements as the metallic reactant to enter the cracking process cycle. The metallic element or elements of the metallic reagent are activated as necessary for adsorption to take place in the zone. regeneration during the steps of the process 2,833,8 according to the invention. This activation appears to cause a partial or substantially complete conversion of the target metal or metals to the corresponding oxide or oxides. These activations are not actually influenced by the way in which the metallic element or elements are chemically bonded in the initial stage after introducing them during the process cycle. The average amount of the metallic reagent in the regeneration zone is sufficient for a significant amount of the amount of sulfur oxides formed by the removal of sulfur-containing carbon deposits has been adsorbed. At least 50%, and preferably more than 80% of the sulfur oxides formed after firing are absorbed by the metallic reagent in the regeneration zone. As a result, the concentration of sulfur oxides in the flue gas stream from the regeneration zone may be no more than about 600-1000 parts per million parts by volume, preferably no more than about 600 parts per million parts by volume, and even more preferably no more than about 400 parts per million 20 parts volume. The amount of metallic reagent used, based on the metal or metals, is preferably from about 25 parts per million to about 7 wt%, more preferably from about 0.01 wt% to about 5 wt%, and most preferably from about 0 wt%. 1% by weight to about 0.5% by weight of the solid particles. Some of the solid particles may contain more than the average amount of metallic reagent in the solid particles, but they are mixed with other solid particles. which contain less than the average amount of the metal reagent, so that the average amount of the metal reagent in the solids corresponds to the above-mentioned level. The desorbed deactivated catalyst is regenerated within the regeneration temperature range, whereby a stable metal and sulfur compound is formed in the solids. This compound is formed from the metal contained in the metallic reagent and sulfur oxide. The regeneration temperatures are preferably from 560 ° C to about 40,790 ° C, more preferably from about 690 ° C to 730 ° C. Cracking of the hydrocarbon feed is carried out at the reaction temperature range where the metal and sulfur compounds in the solids react. forming metal sulfide in a metallic reagent. Cracking reaction temperatures are preferably from about 455 ° C to about 650 ° C, and more preferably 467 ° C-592 ° C. Volatile deposits are evaporated from the deactivated cracking catalyst with a vapor-containing gas in the desorption temperature range. wherein the metal sulfide in the metallic reagent reacts with water; forming hydrogen sulfide gas. Desorption temperatures are preferably from about 455 ° C to about 650 ° C, and more preferably 467 ° G to 538 ° C. The weight ratio of steam to molecular sieve-type cracking catalyst 55 in the desorption zone is preferably from about 0.0005 to about 0.025, more preferably from 0.0015 to 0.0125. The new exhaust gases from the regeneration zone preferably contain at least 0.01 vol.% Oxygen, and more preferably at least 0.5 vol.% Oxygen, to achieve the desired reduction of harmful gas emissions. the metal in the metal reagent an oil-soluble or soluble or dispersible compound is used. The metal reagent is introduced into a macular sieve type cracking catalyst. In this variant of the invention, the solid particles may additionally contain at least one additional component from the group consisting of solids essentially inert to the cracking of the hydrocarbon feedstock and the amorphous cracking catalyst, the metallic reagent being introduced therein. In this embodiment, the compound introduced in the cracking reaction zone, desorption zone and regeneration zone during the cracking cycle is a metal salt. Examples of suitable compounds are metal detonates and metal carboxylates having 1 to 20 carbon atoms. A preferred compound is magnesium acetyl acetate. In another embodiment of the invention, the material "containing a metal in the metallic reagent is a metallic reagent in powder form, for example, magnesium oxide. In yet another embodiment, the material is a metallic reagent deposited on an amorphous cracking catalyst." or on a body substantially inert to the cracking reaction. The invention relates to an improved fluid catalytic cracking process wherein an improved fluid catalytic convention regeneration of the cracking catalyst takes place and an improved process for reducing sulfur oxide emissions in the gas exiting the zone. regeneration of the cracking catalyst and in which the commotion of the sulfur-containing hydrocarbon feed takes place, in the course of which the catalyst is deactivated by depositing the sulfur-containing coke on its surface. Steels according to the invention containing a cracking catalyst of the molecular sieve type and forming a well-dispersed These physical systems are recirculated throughout the cycle of the cracking process in the cracking zone, desorption zone and regeneration zone. The applied conditions reduce the amount of sulfur oxides in the exhaust gas from the regeneration zone. The cracking catalyst and the metal reagent in the process according to the invention perform separate and important functions. The cracking catalyst catalyzes the cracking reactions, while the metal reagent is essentially inert to this mercury and its detrimental effect on the catalytic conversion operations, if necessary. It exists at all, is low under the conditions used. The reduction in the amount of sulfur oxides in the flue gas from the regeneration zone is due to the adsorption of these oxides on the solid particles in the regeneration zone. Also, the molecular sieve-type cracking catalyst often serves as an adsorbent. Sulfur oxides. The metal reactant reacts with the adsorbed sulfur oxides to form a metal and sulfur-containing compound in the solids, especially metal sulfates, and especially alkaline earth metal sulfates. When such a metal and sulfur compound is stable under the operating conditions in the process of operation. regeneration, it can be transferred to k solid surfaces particles to the regeneration zone and the desorption zone, where it is reduced and is acetylated as a sulfur-containing gas, especially in the form of hydrogen sulfide. It is understandable that the activity of reducing sulfur oxide emissions in the exhaust gases from the regeneration zone may be subject to change depending on the metal used as the metal in the metallic reagent. Likewise, the results obtained with the use of a plurality of metals capable of fulfilling the roles of the metal in the metallic reagent need not necessarily equal the results obtained with the use of another metal capable of fulfilling these functions. Different results are also obtained under different conditions. The steels of the particles in the method according to the invention are very fine, their average dimensions are from about 20 microns or even less to about 150 microns, so that the particles are in a fluidizable form. suitable starting materials for the cracking catalyst are silicon dioxide and / or alumina materials. Other refractory metal oxides may be used, which only limits their ability to undergo efficient regeneration under selected conditions. Mixtures of alumina and aluminum may also be used. Preferred catalysts are combinations of silicon dioxide with alumina mixed with "molecular sieves", also called zeolites or crystalline aluminum silicates. Suitable cracking catalysts contain sufficient crystalline gynosilicates to substantially increase the cracking activity of these catalysts, this amount being only minimized by their ability to undergo efficient regeneration under selected conditions. The silicon dioxide to alumina mole ratios in the crystalline aluminosilicates are generally at least about 2: 1, for example up to about 2: 1 to about 12: 1, preferably 4: 1 to 6: 1. Suitable cracking catalysts based on dioxide of silicon are catalysts containing this compound predominantly, e.g. from about 35 to about 90% by weight of silicon dioxide and from about 10 to about 65% by weight of alumina. These catalysts can be prepared by any suitable means, e.g. etc., paying attention only to the fact that the final physical form of the catalyst allows for its fluidization. With appropriate "molecular sieves" Different "are natural or synthetic alumina silicates, for example fotosites, chabasites, X and Y types of aluminosilicates, and ultra-durable crystalline broad porous silicates. When molecular sieves are mixed, for example, with a silicon dioxide-alumina system, to obtain a cracking catalyst in the petroleum raw material, the molecular sieve content of the freshly-pyreated catalyst particles is from about 0.5 to about 50% by weight, preferably 5 to 50% by weight. % by weight. The stable molecular sieve type cracking catalyst may contain only about 1% by weight of the crystalline material. Crystalline aluminosilicates are generally available or are made in sodium form, with typically the amount of the sodium component then being maximally reduced so that it is generally less than about 0.3% by weight. The reduction of the sodium component is carried out by ion exchange with hydrogen ions, with ions that are precursors of hydrogen ions, e.g. with ammonium ions or with polyvalent metal ions, including calcium, strontium, barium ions, rare earth metals, e.g. cerium, lanthanum, neodymium and naturally occurring rare earth elements, as well as their mixtures. Applicable crystalline substances are able to maintain a porous structure under high temperature conditions during the production of the catalyst, Hydrocarbon changes and catalyst regeneration. Crystalline aluminosilicates often have a homogeneous porous structure with extremely small pores; The diameter of the cross-section of the pores ranges from about 6 to about 20x10-10 m, preferably 10-15x10-10 m. Catalytic cracking of heavy mineral oil fractions is one of the basic operations in refineries. It is used to obtain the conversion of crude oil to the desired. fuels such as high-octane gasolines used in spark ignition engines. An example of a "fluidized" catalytic conversion process is the fluid catalytic cracking process in which large molecule liquid or gaseous hydrocarbons contact the fluidized bed in a reactor. a long lifter reactor with hot, very fine particles of solid catalyst, keeping the mixture of catalyst and hydrocarbons at high temperature in a fluidized or dispersed state for a period of time sufficient to achieve the desired degree of cracking for hydrocarbons of lower molecular weight, present in the gasoline, For oil or fuels from distillation The visibility of hydrocarbon feedstocks suitable for use in the cracking process is generally at a higher temperature range than that of gasoline, e.g. in the range of about 205 ° C to about 650 ° C. The cracking temperature of the raw materials is generally from about 455 ° C to about 650 ° C. These raw materials are various fractions of mineral oils boiling in a higher temperature range than gasoline, e.g. light gas oils, heavy gas oils, oils from a wide temperature range distillation, vacuum gas oils, kerosene, decant oils, fractions residuals, reduced crude oils and recirculation oils derived from the above-mentioned, as well as the corresponding fractions of shale oils, tar sand processing products, synthetic oils, coal hydrogenation products, etc. These fractions can be used separately or combined with The method of the invention may be carried out in accordance with any convenient catalytic cracking scheme, although it is preferable to use fluid catalytic cracking in which the conversion of hydrocarbons takes place predominantly in the rare-phase transfer line or in a rising reactor system. with the use of highly active catalysts moving in space and relatively high speeds. It is preferable that cracking occurs essentially in the riser only and not in the dense catalyst bed. In conventional gas oil rising crackers, the throughput ratio or volume ratio of the total feed to fresh feed may vary from 1 to 3 and the conversion rate from about 40 to about 100% by weight, and it is preferable to maintain it. at levels greater than about 60% by weight, e.g. 60-90% by weight. Conversions are understood to mean the percent weight loss of hydrocarbons boiling above about 220 ° G under atmospheric pressure due to the formation of lighter substances or coke. The weight ratio of the total amount of cracking catalyst to oil in the riser reactor can be varied from about 2 to about 20 such that the density of the fluid dispersion is from about 16.02 kg / m3 to about 80.37 kg / m3. 833 12 It is desirable that the ratio of the amount of catalyst to the amount of oil be kept at about 3 to about 20, preferably 3-7. The speed of fluidization in the riser reactor can be varied from about 3 meters / second to about 5 meters / second. The ratio of the height of the riser to the average diameter of the riser is usually around 25. In the production of conventional heavy gasoline, the mixing temperature at the bottom of the riser reactor is preferably maintained at 538 ° C to 592 ° C, so that the oil feed is carried out. volatilized and the outlet temperature at the top is about 510 ° C. Much higher temperatures are necessary for cracking the residual fractions and synthetic fuels. Under these conditions, taking into account the need to immediately separate the spent catalyst from the oil vapors, the contact time between the catalyst and the oil must be very short. The contact time in the riser reactor is typically from 1 to 15 seconds, preferably from 3 to 10 seconds. Short contact times are advantageous because a large proportion of the hydrocarbon cracking reaction occurs in the initial contact period, thus avoiding the undesirable. ' secondary reactions. This is especially important when we want to obtain increased productivity and product selectivity with a reduced amount of coke. Short contact times between catalyst particles and oil vapors can be achieved by various methods. For example, the catalyst can be injected 30 at one or more points located along the lower section of the riser. Likewise, the feed oil may be injected at all points along the lower section of the riser reactor, introducing streams of fresh feed and dung at other points. For this purpose, the lower section of the riser can account for about 80% of the total height of the riser, so that the effective contact times are kept as short as possible and the conversion of the oil feedstock is optimized. When a dense catalyst bed is used, it is also possible to require the injection of the catalyst particles and / or the oil charge directly into the zone of the dense bed by injection of the catalyst bed. These conversion conditions lead to gasoline as a fuel for internal combustion engines with a spark yield, however, the process scheme may be altered as appropriate to obtain heavier hydrocarbon products, eg, turbojet fuel, diesel fuel, fuel oil and chemicals, particularly olefins and aromatics. 50 In the catalytic process, some non-volatile carbon substances or "coke" are deposited on the catalyst particles. Coke contains polynuclear aromatic hydrocarbons, which are usually composed of a small proportion of hydrogen, say from about 4 to about 10% 55 by weight. contains organic sulfur compounds, sulfur is also found in coke. Coke grows on the catalyst, reducing its catalytic activity in the cracking reaction and reducing its selectivity to make a gasoline blend. Catalyst particles 60 can largely regain their initial properties thanks to the removal of most of the coke from them by a suitable regeneration process. The spent catalyst from the kerosene conversion reactor is desorbed prior to entering the regenerator. The temperature in the desorber tank of the fluidized bed catalytic cracking plant is substantially equal to the conversion temperature in the reactor and ranges from about 455 ° C to the eye lo 650 ° C, preferably kept above about 467 ° C. Steam is the preferred stripper gas, although steam containing nitrogen or other steam containing inert or flue gas may also be used. The stripper gas is introduced at a pressure of generally at least about 6.8 bar, preferably about 2.4 bar, which results in substantially complete removal of the volatile compounds from the spent catalyst. The method of the invention may be carried out according to any suitable regeneration scheme. cracking catalyst, although it is preferable to use a regeneration system comprising at least one dense bed and at least one thin phase zone. The particles of desorbed spent catalyst can be introduced into the dense bed zone of the regenerator vessel through suitable lines from the desrober vessel. The inlet may be located at the bottom or to the side, preferably near the top of the fluidized zone of the dense bed. The inlet may also be at the top of the regenerator, whereby the catalyst first contacts in the organic zone of the thin phase with a substantially already consumed regeneration gas. ' Catalyst regeneration occurs by burning off the coke deposits from the surface of the catalyst with a gas containing molecular oxygen such as air. Many regeneration techniques are used in the industry to restore the catalyst to significant catalytic activity depending on the degree of coke removal. In the gradual removal of coke from the catalyst, the most difficult thing is to remove its residues, so in practice an intermediate degree of catalytic activity is accepted, with an economic compromise. Burning coke deposits from the catalyst requires the use of large volumes of oxygen or air. It seems that the oxidation of coke can be presented in a simplified way as the oxidation of carbon, proceeding according to the following chemical equations: CO 2 (b) 2C + 02 ^ 2CO (c) 2CO + 02 2CO2 Reactions (a) and (b) occur in both typical conditions for regeneration of the catalyst, which process may take place in the temperature range from about 560 ° C to about 790 ° C, and these exemplify chemical interactions between gas and solid during catalyst regeneration at temperatures in the above-mentioned range. Each increase in temperature influences the increase of the coal combustion rate and the more complete removal of carbon or coke from the catalyst particles. The increased combustion rate is accompanied by an increased release of heat, and when sufficient free or molecular oxygen is present, the reaction (c) in the gas phase may occur. The latter reaction is initiated and programmed by free radicals and can be catalyzed. The burning of sulfur-containing coke deposits from the catalyst also leads to the formation of sulfur oxides. The burning process can be represented by the following chemical equations. / (d) S (in coke) + 2 SO 2 (e) SO 2 + 1 / 202— ^ SO 3 14 Reactions (d) and (e) also take place under the typical conditions of the cracking catalyst regeneration process. it runs fast, the reaction (s) is relatively slow. The reactions (e) can be catalyzed by any of the catalysts catalyzing the above-mentioned reaction (c). The molecular sieves adsorb the sulfur oxides, and therefore the reaction (s) may take place on the solid particles of the cracking catalyst of the invention. The other solid particle components of the invention also have the ability to adsorb sulfur oxides. The resulting sulfur trioxide can react with a suitable metal, especially a metal oxide in a metal reagent, to form a stable metal sulfate in the solids. After the solid particles are separated from the flue gas stream leaving the regeneration zone, the metal sulfate in the solid particles is returned to the reaction zone. This prevents the escape of sulfur in the form of gaseous sulfur oxides from the regeneration zone. Sulphate remains on the solid particles as they pass through the reaction zone and is converted into a metal sulfide in a metallic reagent and, in a measure, into hydrogen sulfide in the reducing atmosphere prevailing in this zone . During desorption of the vapor-containing strip gas in the stripping zone, the sulfur is converted to hydrogen sulfide and is discharged in the gas stream leaving the strips. In this way, the metallic reaction is regenerated and becomes again capable of reacting with sulfur oxides the next time it passes through the regeneration zone. Hydrogen sulphide can be recovered with the cracking products from the desorption zone, separated and converted into elemental sulfur in known devices. It seems that the discussed reactions can be summarized as follows: * Regeneration: MO + SO2 + 1/2 Ó2 or MO + SO3 MSO4 Reaction: MSO4 + 4H2NMS + 4H20MO + H2S + 3H2O Desorption: MS + H2O MO + H2S These reactions are possible due to the simultaneous use of a molecular sieve-type cracking catalyst and a metal reagent according to the invention. The presence of the metallic reagent does not substantially contribute to the high cracking catalytic activity normally exhibited by a molecular sieve catalyst. Thus, with the assumed feed conversion and crack yield, a reduction in the emission of sulfur oxides is obtained at the same time. be finely divided, for example in the form of a powder, not combined with a molecular sieve type cracking catalyst or any other carrier. In this case, the metallic reagent is separately introduced as a powder during the catalytic cracking process cycle and then mixed with the molecular sieve-type cracking catalyst in situ during the cycle. The metal reagent is not introduced during the cycle upstream of the cracking catalyst. - In general, the powdered form of the metallic reagent is advantageous, as it is then easy to introduce into the fluidized catalytic cracking system and is easy to handle in this system. The size of the powder particles should be chosen so as to avoid segregation at fluidization velocities. It is desirable that the powder particles are not small enough to create the problem of excessive emission in gases as solid particles entrained from the bed. In 5 fluid catalytic cracking operations, filters, cyclones, dust collectors, etc. are used to recover most of the entrained solid particles and return them to the system to reduce losses. The powder should be sufficiently resistant to abrasion and excessive degradation. Generally, the average particle size of the powdered metallic reagent is from about 0.5 or 1 to 100 microns, preferably less than about 30 microns in diameter. Micro-dimensional particles, that is, particles less than 1 micron in size, e.g., from about 0.01 to about 0.05 microns, may tend to form larger sized aggregates; such aggregates may also be advantageously used in a longitudinal process. Examples of powdered metal reagents suitable for use in this process are magnesium oxide and calcium oxide, dolomite and Trimex, manufactured by Trimex Corporation and described in US Patent No. 3,630,696. The metal reagent may also be incorporated into the invention. A suitable non-cracking catalyst of the molecular sieve type, outside the cracking cycle, and these compositions are then introduced during the cycle, ¬ nothing it becomes part of the solid particles. Such a carrier may be an amorphous cracking catalyst or a solid essentially inert to the cracking reaction, which may, for example, be in the form of a ceramic material. In this case, the metallic reagent deposited on the carrier is then mixed with a cracking catalyst of the molecular sieve type. during the cracking cycle, the catalyst is introduced first in this cycle. It is desirable that the carrier is porous and that its surface area including the pores on the surface is at least about 10, preferably at least 50 m2 / g. Examples of suitable carriers are silicon dioxide, alumina, silicon dioxide-alumina system. etc. The metal reagent can be introduced to such a substrate by ion exchange, saturation or other methods - by contacting the substrate or its component with a solution or solutions of the metal compound or compounds of the metal reagent, using 50 of them in an amount sufficient to obtain the desired concentration of the metal reagent, according to the requirements of the invention. The metallic reactant may be combined with such a substrate either during any of the substrate preparation steps, or with an already finished substrate. One method of introduction is to subject the substrate to ion exchange. Ion exchange can also be applied to silicon solids and clays, using a solution or solutions of the compound or compounds of the metal element or elements of the metal reagent. Suitable compounds for this purpose are metal halides, preferably chlorides, nitrates, amine halides, oxides, sulfates, phosphates and other soluble inorganic salts as well as carboxylates including. 65 16 containing 1-5 carbon atoms in the molecule and alcohols. The metal reactant can also be introduced into or part of a molecular sieve type cracking catalyst during the catalytic cracking cycle, with no metallic reagent introduced upstream of the catalyst. In this case, the metallic reagent is introduced into the cracking catalyst during the cycle of the cracking process. When choosing the method of introduction, care should be taken that the activity and selectivity of the cracking catalyst do not change adversely. In each of the above cases, there is no certainty as to the mechanism by which the metallic reagent is introduced into the catalyst. cracking like a molecular sieve, an amorphous cracking catalyst or a substantially inert substrate. Metals can form complex bonds with the carrier material and other solid particle constituents. It is understood that the terms "metallic reagent" and "incorporated" into a substrate as used herein refer to the metals of that constituent present inside the potty as a composition and / or in an element state. The saturation can be carried out by all methods which do not damage the structure of the substrate. Saturation with a metallic reagent of a cracking catalyst of the molecular sieve type - The saturation of the inert carrier for the cracking reaction or the amorphous cracking catalyst is carried out either during the cycle or off-cycle. Saturation is different from ion exchange. As a result of impregnation, a better deposition on the surface and, above all, a physical bond with the surface is achieved, while in the case of ion exchange the bonds are mainly of a chemical nature, and more diffusion causes less deposition on the surface. In the case of impregnation, the metal is deposited on the substrate with essentially no ion exchange between the metal and the substrate. When saturating the substrate, the metal or metals of the metallic reagent may be present in the k or compounds which are soluble in water, relatively soluble or dispersible in organic solvents, and the amount or amounts of these compounds must be selected so that these compounds are contained metal or metals in an amount that would be on the substrate in contact with them. The compositions may be dried to remove the solvent to provide the metallic reagent deposited on the substrate. It is preferable to use impregnating solutions containing water-soluble nitrates because the residual thermal decomposition of nitrates is relatively harmless in terms of the activity of the hydrocarbon cracking catalyst. Metal halides and sulphates can also be used for saturation, but since the byproducts of thermal decomposition of these salts can adversely affect the activity of the hydrocarbon cracking catalyst, they are most commonly used to deposit a metallic reagent on substrates that are essentially inert to the cracking reaction and not They have a distinctly detrimental effect on the cracking reactions of Hydrocarbons. Another method of physically depositing a metallic reagent on a substance, especially on porous substances such as crystalline aluminosilicates, is by adsorption. 25 30 35 40 45 50 55 60 112 833 17 the substance of the fluidized bed degradable compound or compounds of the metal or metals of the metallic reactant, followed by thermal or chemical decomposition of the compound or compounds. The substrate can be activated by heating it to remove adsorbed water, and then contacting the liquid bed susceptible to decomposition. a compound or compounds of mtal or metals as a reactant a metallic compound, thereby adsorbing the compound or "compounds onto the substrate. Typical examples of these compounds are alkylmethacin, volatile metal halides, etc. The adsorbed compound or compounds can then be reduced thermally or chemically to their active state to obtain an evenly dispersed active metallic reagent on the substrate. The thermal reduction can be carried out e.g. during the regeneration process. It is also advantageous to introduce the metal compound or compounds of the metallic reactant during the cycle of the cracking process and to discharge them into the substrate in situ. Such a compound or compounds may be incorporated in an oil-soluble or relatively water-soluble solid, liquid or gaseous form at any stage of the cracking process cycle. A considerable dispersion in the solid particles is thus achieved. Such a compound or compounds can, for example, be mixed with the feed or gas for fluidization in the reaction zone, with a regeneration gas, fuel oil or water in the regeneration zone, or with a stripper gas in the desorption zone, or introduced in a separate stream. In situ compounds are metal salts, for example metal detonates or metal carboxylates containing from 1 to 20 carbon atoms. A particular example is magnesium acetoacetate. Preferred variants of the process of the invention are those involving regeneration carried out in accordance with the regeneration scheme described in US Pat. US Am. No. 3,909,392. This embodiment, referred to herein as an atane technique, relates to an improved catalytic cracking process including an improved method of regenerating a catalyst used for fluid catalytic conversion of hydrocarbons in which the catalyst is deactivated by coke depositing on it. surface. This process makes it possible to obtain a regenerated catalyst with as low a coke content as possible, while maintaining a favorable heat balance in the conversion apparatus and with a minimum carbon monoxide content in the Uin gas stream. The heat generated during the combustion of carbon monoxide is absorbed by the regenerated catalyst, thus obtaining some of the heat needed in the hydrocarbon conversion zone. In one variant of the process according to the above patent, almost complete combustion of carbon monoxide to carbon dioxide is carried out inside the tank of the device for regeneration, in a second, relatively sparse catalyst regeneration zone, the temperature of this process being desirable to be from about 650 ° C to about 815 ° C, preferably from about 675 ° C to 788 ° C. The temperature in the second zone may be about 10 ° C to about 40 ° C higher than the temperature in the first regeneration zone. A partially regenerated catalyst from the first relatively dense regeneration zone may flow through the second zone in an amount and amount in a controlled manner. a flow rate sufficient to absorb substantially all of the heat generated during bonding in the second zone. Although most of the coke is burned off the catalyst in the first zone, additional coke is burned off the partially regenerated catalyst while it is in the second zone, after which the substantially coke-free catalyst can be returned to the hydrocarbon conversion step. variant of the process described in U.S. Patent No. US Am. No. 3,909,392, substantially complete firing including both coke or carbon oxidation on a catalyst, and carbon monoxide oxidation occur within one relatively dense regeneration zone by appropriate control of, in particular, the regeneration temperature and gas velocity. The invention is carried out in variants including the regeneration scheme described in US Pat. US Am. No. 3,909,392, the main amount of the heat generated by the combustion of carbon monoxide in the regeneration zone is absorbed by the solid particles of the invention containing the cracking catalyst, which is part of the heat required in the cracking zone. It is advantageous that the method according to the invention is According to the invention, according to the described embodiments, it is possible to prevail the combustion of coke and carbon monoxide in the dense phase, if present. There is a much greater amount of solid particles in this phase than in the rare phase zone, if present, so that these particles absorb the heat that is released to a much greater extent. Since "the proportion of combustion in the dense phase is increased, the amount of heat generated in the dense phase is increased. in the rare phase zone, the need for a rapid exchange of solid particles in the rare phase zone is significantly reduced or eliminated. The process carried out in accordance with the above variants includes the use of solid particles according to the invention, containing a cracking catalyst of the molecular sieve type and a metallic reagent According to the invention, in a system in which there is substantially complete combustion of the carbon monoxide. The low coke contents on the catalyst obtained in this process correspond to amounts of less than 0.2% by weight, preferably less than about 0.05% by weight. flue gas obtained in the process may contain less than about 0.2% by volume of carbon monoxide, e.g. 500-1000 parts per million, even 0-500 parts per million. The process also results in the recovery of the heat generated by its direct transfer to solid particles in the reservoir of the regenerator. The velocity of the gas causing fluidization in the dense zone of the regenerator may be about 0.06-1.2 m / sec, preferably about 0 , 15-0.9 m / second. The regeneration gas for fluidization of the dense bed contains free or molecular oxygen, and it is preferable to introduce into the regeneration device some excess oxygen in relation to the amount needed to completely burn the coke, both carbon and hydrogen into carbon dioxide and water vapor. . The amount of excess oxygen may vary from about 0.1 to about 25 percent or more of the theoretical stoichiometric amount of oxygen needed for complete combustion of the coke, but it is preferred that the excess amount does not exceed about 10%. For example, when a regenerative gas is used, 10 15 20 25 30 35 40 45 50 55 60 112 833 19% of air, this 10% excess air will result in only about 2% by volume oxygen in the exhaust gas stream. It is preferred that at each point of the regeneration apparatus the molecular or free oxygen and carbon monoxide concentrations lie outside the explosive concentration range, preferably the carbon monoxide concentration lies outside the explosive range under the given conditions to eliminate any risk of explosion. The regeneration gas, in addition to free or molecular oxygen, may contain an inert or diluting gas, e.g. nitrogen, water vapor, etc., recycle gas from the stream leaving the regeneration zone and other similar gases. Typically, the oxygen concentration in the regenerator gas at the entrance to the regenerator is around 2-30 % by volume, uses 5-25% by volume. Since air is most often used as the source of oxygen, a significant proportion of the inert gas can be nitrogen. The inert gas can be used to dissipate the excess heat generated during the burning of the coke from the catalyst. The source of the hot inert gas is the gas stream leaving the regenerator, and some of this gas can be returned to the regenerator and, for example, combined with sufficient feed. regenerator of air or other oxygen-containing gas, with the inclusion of almost pure oxygen, to obtain the desired content of this element. Thus, the recirculating gas can be subjected to direct heat exchange, raising the temperature of the regenerating gas, which gives even further heat savings in the system. According to the invention, they can be transferred from the sparse zone into a partial separation zone, usually provided with multi-stage cyclones. From these cyclones, the solid particles can be returned directly to the dense bed via the inclined legs, and the spent regenerative and combustion gases are collected in a collecting chamber and finally subjected to the recovery of the heat energy contained therein. The processes of recovering heat from the flue gas include the production of steam water, desorption of spent catalyst, indirect heat exchange with various refinery streams, e.g. with the feedstock for a specific conversion process, as well as in various dryers and evaporators. The attached figures, Figs. 1 and 2, show the projections. vertical, partly in cross-section, variants of apparatus suitable for the regeneration of the catalyst which performs the process of the invention according to the regeneration scheme described in US Pat. US Am. No. 3,909,392. Such apparatus may advantageously be used with many existing petroleum hydrocarbon cracking plants, and particularly with fluid catalytic cracking plants equipped with various spatial cracking, desorption and regeneration section units. 1 is an illustration of an embodiment of the invention in which desorbed spent catalyst from a cracking reactor (not shown) feeds the regenerator from below. Solid particles containing the spent catalyst saturated with a metal reactant, passing from the desorption zone connected to the outlet of the catalyst from the reactor, flow through the bottom of the vessel 1 of the regeneration device. The solid particles flow upwards through the inlet conduits 2 and 3 and flow into the dense bed area through outflow heads 4 and 5. A dense catalyst bed is maintained in the lower part 6 of the regeneration tank and extends upwards to the interface 7. Particles constantly in dense bed they achieve a fluidized state due to the flow of combustion air through conduit 8, valve 9 and conduit 10 into air ring 5. Substantially balanced patterns of air flow through the regeneration zone can be achieved, if desired, by using additional air rings not shown. Burning with air 10 on the spent coke catalyst begins in the dense bed. Higher temperatures can be achieved here by periodically burning a stream of fuel oil, for example, decant oil, inside the bed. The fuel oil can be added via line 12, valve 13 and a line 14 connected to a nozzle located above the air ring 11. The velocity of the air that causes fluidization causes some solid particles to be continuously transferred upwards to the rare phase zone. which occupies the upper part 15 of the regeneration vessel, i.e. the part above the interface 7. The combustion of coke continues in the thin phase zone, and the largely used combustion gas along with entrained solid particles is discharged into cyclones 20 and 21 - these are 25 first stage cyclones. Most of the solid particles are separated in the first stage cyclones and flow downwards with sloping legs 22 and 23 into the dense phase zone. Gases and other solid particles pass through interstage lines 24 and 25 to cyclones 26 and 27 - these are second stage cyclones. In these cycles, essentially all of the remaining solid particles are separated and flow down into the dense bed with inclined legs 28 and 29. Then, the substantially used combustion gas flows through lines 35 30 and 31 to the collecting chamber 32 and finally it is fed from the regeneration device through line 33. The resulting stream can be subjected to a suitable heat exchange, which has not been shown in the drawing, with a refinery stream or for the production of useful steam 40. Solid particles containing the regenerated catalyst are discharged from the dense the bed back to the reactor through pressure pipes 34 and 35, equipped with collecting heads 36 and 37. The combustion air normally provides an excess of oxygen in relation to the amount needed to completely burn the coke from the catalyst particles into steam and carbon dioxide. However, according to one embodiment of the invention, the regeneration scheme described in US Pat. on Am. 3,909,392 "combustion of coke in the dense bed may be incomplete. In this situation, the combustion gases rising from the dense bed zone contain a significant amount of carbon and carbon dioxide as well as oxygen. The remaining coke and carbon monoxide on the catalyst burns up. substantially completely in the rare phase zone, with a lot of heat being produced. When carbon monoxide is burned in the rare phase, a significant portion of this zone is typically occupied by a high temperature zone, present approximately in the region denoted especially by X. High temperature zone. one can easily see 60 through a window not shown in the figure located at the height of this zone. The control of the regeneration temperature inside the rare phase zone is partly possible due to the absorption of heat by the mass of solid particles carried upwards by the ascending gas stream 65 for combustion or blowing upwards from a dense bed 112 S33 21 through a spray pipe 40 and a distribution head 41 solids, as a result where the rain or the fountain of solid particles is dispersed in the rare phase zone. The solid particles can be blown out using air, steam or other inert gas introduced via line 42, valve 43 and an injection tube 44, a short length of which extends to the lower end of the ejector tube 40. Excessive temperature formation in the top section of the regenerator may also be used. to be prevented by the introduction of steam, "e.g. through lines 45 and 46, valve 47 and line 48 to the steam dispenser 49. The temperatures adjacent to the collecting chamber can also be controlled by supplying steam through line 50, valve 51 and line 52 to the ring dam 53 surrounding the collection chamber 32. If desired, additional cooling can be applied by means of a spray of water not shown in the figure, which can preferably be directed to the area containing the interstage lines 24 and 25 cyclones. This reduction in temperature favors the formation of The phase of regeneration of a stable compound containing metal and sulfur. Figure 2 shows Another embodiment of the invention according to the regeneration scheme described in US Patent US Am. 3,909,392. In this variant, solid particles containing desorbed spent catalyst and metallic reagent passing from the cracking reactor feed the lateral regeneration device. The solid particles containing the catalyst saturated with the metallic reagent used enter the regenerator tank 101 by flowing downward through the inlet conduit 102 which passes the side of the tank. Thus, the entrance to the dense bed is in the area of the lower portion 106 a short distance below the interface 107. Fluidization of the solid particles produces combustion air supplied through line 108, valve 109 and line 110 to the air ring 111. If there is a need to balance the air flow through the regeneration zone, additional rings, not shown in the drawing, can be used. As already mentioned in the description of Fig. 1, the combustion of coke on the spent catalyst particles begins in the dense phase zone, in which a stream of fuel oil can be dropped periodically, if desired, to obtain higher temperatures. The fuel oil can be added via line 112, valve 113 and line 114 terminated by a nozzle. The velocity of the air causing fluidization can be adjusted so that it continuously transports upwards continuously particles whose task is to absorb heat in the rare phase zone located at the top. 115 of the regeneration tank, i.e. the part lying above the interface 107. The combustion of coke, as well as carbon monoxide, may proceed further in the rare phase zone, after which the largely consumed combustion gas along with part of the constant time entrained by its stream the teak is discharged into cyclones 120 and 121, which are first degree cyclones. Most of these solid particles are separated in the first stage cyclones and by sloping legs 122 and 123 conveyed down to the dense bed zone. The gases and the remaining solid particles then pass through interstage lines 124 and 125 to cyclones 126 and 127, which are second stage cyclones. In them, essentially all the remaining parts of the solid particles are separated, which, by inclined legs 128 and 129, extend down to the zone of the dense bed. The largely used combustion gas then flows through lines 130 and 131 to the collection chamber 132 and is finally discharged from the regeneration vessel via line 133. Solid particles containing the regenerated catalyst leave the dense bed through pressure pipes 134 and 135 from the pressure equipment. The collector heads 136 and 137 return to the cracking reactor. As already mentioned in the description of the embodiment illustrated in Figure 1, the carbon monoxide burns in the thin phase, creating a high temperature zone occupying most of the thin phase zone. and in particular the region the approximate position of which is indicated by X. The regulation of the regeneration temperature in the rare phase zone is largely due to the absorption of heat by the mass of the upward solid particles by the ascending stream of combustion gas. The temperatures in the vicinity of the collection chamber, cyclones, and interconnecting lines can be lowered, if desired, by introducing water vapor through line 150 of valve 151 and line 152 and an air ring 153 surrounding the collection chamber 132. Spray jets of water, not shown in the figure, can also be used. According to another, particularly advantageous variant of the process according to the invention, the operating parameters are substantially changed by using the apparatus shown in Fig. 2, compared with those of the variant described above. The gas velocity and the solid particle inflow are selected so that substantially all of the coke and carbon monoxide combustion occurs in the dense phase and the heat is dissipated into the bed. When the system is operated according to either of the first two variants described above, the recovery of the heat produced by the substantially complete combustion of coke and carbon monoxide takes place by the absorption of this heat by the solid particles in both phases, with the return of the solid particles to the dense zone. it makes it possible to maintain a sufficiently high temperature in the zone of the dense phase. The recycled particles can carry additional heat to raise the temperature of the dense phase to a temperature conducive to removing extra layers of coke deposits, whereby the combustion of the coke layers is soaked almost completely. When the system is operated so that substantially all combustion takes place in the dense phase of the catalyst, the heat dissipates in this phase and is absorbed by the solid particles in the fluidized state, and the last layers of coke are therefore burnt. Thus, in all variants, the solid particles containing the regenerated catalyst returning from the regenerator to the cracking reactor range from about 0.01% to about 0.1% by weight, preferably 0.01% to 0.05% by weight. , more preferably about 0.01% - 0.03% by weight of the carbon or coke deposited on the catalyst, which may leave the regeneration zone at a temperature suitable for cracking the reactor. The outstanding advantage of the method is According to the invention, it is a fact that the regenerated catalyst has activity and selectivity characteristics similar to those of a fresh conversion catalyst, making it particularly useful in the conversion processes occurring with very short contact times in ascending reactors. . The catalytic activity exhibited in cracking processes by molecular sieve catalysts * as well as their selectivity in converting hydrocarbon feedstocks to the desired products changes very clearly in favor of the more efficient removal of residual carbon or coke from the catalyst during regeneration. The low level of coke on the regenerated catalyst is particularly desirable in the case of fluidized cracking catalysts containing catalytically active crystalline aluminosilicates. In this way, a higher yield of the conversion products can be obtained. Cracking processes in which the regeneration zone consists of from the lower zone of the dense phase and the upper zone of the rare phase, the oxidation of carbon monoxide to carbon dioxide can be mainly, often at least 60%, sometimes around 65-95%, or even completely, in the regenerator's dense phase. in the dense phase oxidation of carbon monoxide to carbon dioxide, additional heat is produced to support the combustion of the coke deposits in a fluidized bed catalyst. Moreover, when a significant portion of the carbon monoxide is oxidized in the dense phase, less carbon monoxide remains to be burned in the rare phase of the catalyst, therefore the post-combustion phenomenon and high temperatures resulting from the uncontrolled combustion of carbon monoxide can be significantly reduced or eliminated in the upper part of the regenerator, which can be detrimental to the reactor's structural materials, exhaust flue gas, devices which erupt solid particles from the exhaust gas, e.g. cyclones, and also adversely affect the activity of the catalyst. Solid particles containing the regenerated catalyst with an unusually low content of residual coke, it is discharged from the dense bed and, at a temperature close to that of the bed, is transferred to a reactor, where it is brought into contact with fresh hydrocarbon feed or its mixture with recirculating hydrocarbon fractions. Since the oxidation of the carbon monoxide from the combustion of the coke deposits from the catalyst can occur mainly in the dense phase, and preferably completely completely in this phase, the regenerated catalyst can be returned to the cracking reactor at a much higher temperature and in a state of much higher activity than is expected. known processes. The main advantage of the present invention is that it is possible to obtain an extremely low content of carbon monoxide in the gas stream exiting the regenerator, while the flue gas from the conventional cracking catalyst regeneration process generally contains about 6 to 10% carbon monoxide, similar to the amount of carbon monoxide and very little oxygen, the carbon monoxide content of the modified regeneration flue gas may be kept below about 0.2% by volume, e.g. from about 500 to 1000 parts per million by volume (ppnlv). In preferred cases, the amount is even lower, such as, for example, from 0 to 500 parts per million by volume. Such a low concentration of carbon monoxide in the waste gas stream allows them to be released into the atmosphere, as it complies with the ambient air pollution standards. If desired, the residual carbon monoxide can be burnt at the outlet of the flue gas discharge chimney of the regeneration device. This advantage of the invention allows for the additional elimination of the investment costs usually associated with the construction of carbon monoxide combustion devices combined with turbine devices and other equipment designed to partially recover the energy generated during the oxidation of carbon monoxide, and are also satisfied. still the requirements of the current air pollution standards in terms of carbon monoxide emissions. Thus, the method according to the invention allows additional advantages to be obtained. These benefits are related to the problem of afterburning and the heat balance. A major problem that is often encountered in practice and that is usually avoided, particularly in the case of fluidized catalyst regeneration, is the phenomenon known as afterburning, described, for example, by Hengstebeck in Petroleum Processing, McGrow-Hill Book Co., 1959 on pages 160. and 175 and discussed in Oil and Gas Journal, 53, 3, 1955 pages 93-9i. The above term is used to describe the further combustion of carbon monoxide into carbon dioxide, according to reaction (c), which is strongly exothermic. Afterburning was avoided in fluidized regeneration processes, as it could lead to high temperatures, threatening to damage the equipment and causing continuous deactivation of the cracking catalyst particles. Afterburning has progressed in the case of many fluidized catalyst regeneration operations, and a whole field of knowledge has been developed dealing with methods of regeneration techniques to avoid this effect. In recent times, increases in regeneration temperatures have been used for various reasons; In particular, methods have been developed to regulate the regeneration temperatures in the initial post-combustion stage by regulating the supply of oxygen to the regenerator vessel, as described, for example, in US Pat. US Am. No. 3,161,583; 3,206,393 and 3,513,087. 40 According to current practice of avoiding burn-up, the exhaust gas from catalyst regeneration typically has a very low oxygen content and a significant amount of carbon monoxide and carbon dioxide in almost equimolar amounts. The process of further combustion of carbon monoxide to carbon dioxide is an efficient source of thermal energy since reaction (c) is highly exothermic. The afterburning can proceed at a temperature above about 592 ° C, releasing a heat of approximately 1.013 107 joules per kg of carbon monoxide oxidized. This amount of heat 50 is generally about 1/4 of the amount of heat developed in the combustion of the coke. The combustion of the carbon monoxide can be carried out in a controlled manner in the standing zone or in the carbon monoxide afterburner after the exhaust gas has been separated from the catalyst. tor, as described, for example, in US Pat. No. 2,753,925, with the released thermal energy. can be used in a variety of refining processes, such as the production of high pressure steam. Other ways of using this thermal energy are described in US Pat. US Am. No. 3,012,962 and 3,137,133 (for turbine drive) and 3,363,993. (pre-heating of oil). The heat recovery processes require separate and complex equipment, but they do reduce the discharge of carbon monoxide 55, a component of the exhaust gases into the atmosphere, 112 833 25, thus avoiding the potential risk of serious environmental pollution. Silicon dioxide-background catalysts Alumina, which has been used extensively for many years in various cracking processes of petroleum hydrocarbons, is not particularly sensitive to the level of residual coke on the catalyst when this level does not exceed 0.5% by weight. Catalysts based on the khzmium dioxide-alumina system, however, were largely replaced by catalysts with additionally added crystalline aluminosilicates, also known as zeolites or molecular sieves. Catalysts containing molecular sieves are much more sensitive to the bottom of residual coke. which has a significant impact on the activity of the catalysts and their selectivity in the process of converting the raw material into the desired product or products. Since conventional techniques for regenerating catalysts find it difficult to remove the residual coke layers, the level of coke obtained in practice usually corresponds to a residual coke content on the regenerated catalyst in the range of about 0.2-0.3% by weight. The ability to achieve enhanced activity and selectivity of molecular sieve cracking catalysts at low coke contents is a strong incentive to seek ways to further reduce residual coke levels. It is highly desirable to achieve a coke level of less than 0.05% by weight, although this is normally not possible under industrial conditions. The necessity to increase the regeneration equipment, greater catalyst losses, significant heat losses, etc., discourage attempts to obtain such perfectly stable catalysts. Many fluid cracking plants operate on a heat balance principle based on process utilization. However, such installations cannot fully exploit the advantages of cracking catalysts, especially zeolite catalysts, which are manifested especially in a rising reactor, where the contact times of the catalyst and oil vapors can be kept as short as possible. Operations combining a high degree of conversion with a high selectivity are favored by a low ratio of catalyst to oil in the riser reactor, leading to the formation of less coke, which, when burned in the regeneration unit, produces heat. Thus, in order to raise the temperature of the catalyst, it is often necessary to use an external heat source, for example a furnace to preheat the raw material, or possibly the installations can be supplied with fresh raw material at a lower temperature. These undesirable necessities can be avoided or reduced considerably by using the method of the invention which allows for the efficient recovery of additional heat by means of solid particles transferred to the rising reactor. The heat produced by the combustion of coke in conventional operations is about 2.793 107 joules / kg. The process according to the invention may make it possible to increase this heat to about 3,857,107 joules / kg. Higher heat generated during the combustion of coke may lead to "an increase in regeneration temperatures, a reduction in the level of coke on the regenerated catalyst, and a lower circulation rate of solid particles, with increased efficiency from individual conversion stages. Example I. 6.9 g of lubricating oil addition contains - 26% by weight of magnesium in the form of magnesium oxide, magnesium carbonate and magnesium polypropylbenzene sulphonate were dissolved in 33.1 g of light catalytic cracking recirculating oil. 5 10 g of this solution was cracked in a laboratory cracker. This bed was 220 grams of a stable industrial cracking catalyst containing 2.5 wt% molecular sieve and about 0.6 wt% sodium. The catalyst was sourced from an industrial fluidized catalytic cracking plant after Withdrawal from which it was calcined The recycle oil was cracked for 4 minutes at temperature 370 ° C. The catalyst beds were purged with nitrogen for 10 minutes at 678 ° C and then cooled to 370 ° C. The cracking, purging, and regeneration cycle was repeated until the catalyst had magnesium, zinc and phosphorus contents of 1100, 703 and 59 parts per million, respectively. Zinc and phosphorus were previously contained in the catalyst. Example II. The procedure of Example 1 was repeated except that using 10 g of a solution containing 6.5 g of oil and 3.5 g of a lubricating oil additive containing 1.6% by weight of zinc, 1.3% by weight of phosphorus and 4.6% by weight of The magnesium cycle of cracking, blowing and regeneration was repeated until the catalyst had a magnesium, zinc and phosphorus content of 2400, 1200, and 1097 parts per million, respectively. 30 Example III. The procedure of Example 2 was repeated, except that a stable, commercially available Krakow catalyst was used which contained 3.3% by weight of a molecular sieve in the silicon dioxide-alumina system as the base material, with it also came from an industrial fluidized catalytic cracking plant, after which it was calcined, and the cracking, blowing and regeneration cycle was repeated until the catalyst had a magnesium, zinc and phosphorus content of 4600, respectively, 304 and 1,136 parts per million. Examples IV to VIII. Various impregnated catalysts were tested for their ability to reduce sulfur dioxide emissions in the exhaust gas from the regeneration zone using a laboratory regeneration device. A synthetic flue gas consisting of 1,500 parts per million sulfur dioxide, 4% by volume oxygen, 4% by volume steam and the remainder of nitrogen was passed through a solid fluidized bed 50 formed by a metal-saturated molecular sieve cracking catalyst. The bed was kept in a glass regenerator surrounded by a heater producing the desired regeneration temperature of 678 ° C. The catalyst temperature was stirred with thermocouples. A cyclone was used to separate the catalyst entrained in the gas leaving the regenerator and to recycle this catalyst to the bed. The operating time of the regenerator under the conditions indicated was 40-90 minutes to provide a sufficient time period of 60 to establish the oxidation state of the medal on the catalyst. The sulfur dioxide content of the gas exiting the regenerator was continuously analyzed with a UV analyzer. . The amount of sulfur dioxide removed from the flue gas 65 from the regeneration zone was calculated as the difference27 112 833 Table I 28 Example Time 0-10 10-20 20-30 30-40 Amount of sulfur dioxide removed (% by volume) 1 IV | May 78—63 63—43 43—32 32—27 85—82 82—78 78—74 74r-70 VI 92—91 91—89 89—88 88—87 VII, 36—24 24 ^ 16 16—14 14 ^ 13 VIII | 60-49 49-39 39-33 33-30 1 between the sulfur dioxide content in the fresh mixture of synthetic gas and in the gas leaving the regenerator. Table I shows the relationship between the volume percentages of sulfur dioxide removed from the flue gas from the regeneration zone and the time that has elapsed since the start of the test. The volume of sulfur dioxide removed decreases with time as the surface of the catalyst becomes saturated. Comparative Example IV uses the unsaturated stable catalyst of Examples I and II, and the flow rate of the synthetic exhaust gas mixture was 1084 ml / minute. . In Examples V and VI, the saturated flue gas engines obtained in Examples I and II, respectively, were used, and the synthetic flue gas mixture flow rates were 989 and 1014 ml / minute, respectively. Example VII is a comparative example using an unsaturated gas mixture. the catalyst of Example III, with a flow rate of the synthetic flue gas mixture of 891 ml / minute. In Example VIII, the saturated catalyst obtained in Example III was used and the flow rate of the synthetic flue gas mixture was 992 ml / minute in this example. Flow rates were measured at 15.5 ° C. Examples IX-X. In Example IX, the procedure of Examples IV to VIII was repeated, except that a synthetic flue gas mixture containing 4% by volume of carbon monoxide, oxygen and water vapor, and the remainder of nitrogen, passed through the fluidized bed at a rate of about 1000 ml / minute (measured at 15.5 ° C). The bed was a mixture of powdered magnesium oxide having 5 microns and smaller particles and an unsaturated, calcined, stable, industrially used molecular sieve catalyst containing 5.3% by weight of crystalline ion exchanged with hydrogen and rare earth elements. of a Y-type alumina and a silica-alumina system, consisting of 30% by weight of alumina, the catalyst used in place of the saturated catalyst. A mixture containing 0.3% by weight of magnesium oxide and about 70% by volume of carbon monoxide was converted to carbon dioxide. In Example X, under the same conditions as in Example IX, using the unsaturated catalyst of Example IX but not using magnesium oxide, a 58% vol / vol conversion of carbon monoxide to carbon dioxide was carried out. Examples XI-XII. In Example 11, a gas oil charge containing 1.67% by weight of sulfur was cracked on an industrial fluidized catalytic cracking plant equipped with a riser reactor using a known regeneration method. An industrial stable molar sieve type cracking catalyst containing 2.5% by weight molecular sieve and about 0.6% by weight sodium was used. In Example 12, another gas oil feed containing 1.68 wt.% Sulfur was cracked on the same plant. The same regeneration scheme was used and the same cracking catalyst was used, but additionally saturated with magnesium and zinc. Magnesium and zinc were deposited on the catalyst by introducing small amounts of magnesium sulphate and magnesium dialkyl dithiophosphate in the form of lubricating oil in the charge into the fractionation zone. After several hours of addition, the content of magnesium and zinc on the cracking catalyst was 0.3, respectively. % by weight and 0.1% by weight. The operating conditions and the composition of the exhaust gases from the regeneration zone are shown in Table 2. Table II Example Cracking conditions Cracking temperature, ° C Total feed rate, m3 / day Process ratio Catalyst circulation speed, tons / minute Weight ratio of catalyst to oil Desorption conditions Desorption temperature, ° C Number of kg of water vapor per ton of catalyst Regeneration conditions Temperature in dense bed, ° C * Air supply rate for combustion, kg / hour Composition of gas leaving the CO 2 regeneration zone, mole% CO, mole% O2, mole% SO2, parts by volume | per million (ppmv) • 11 523.3 7821.32 1.07 29.1 5.3 521.1 3.90 688 186880 13.0 5.0 0.5 580 12 521.1 7439.80 1.25 26.4 5.2 518 4.26. 702.7 220899 14.0 5.6 2.0 60 1 Claims 1. Cyclic method of fluidized catalytic cracking of hydrocarbon feed containing 0.2-6% by weight of sulfur in the form of organic sulfur compounds, which reduces the emissions sulfur oxides in the gas stream leaving the regeneration zone by feeding the hydrocarbon feedstock to cracking in the reaction zone using molecular sieve type cracking catalyst particles in a fluid state; separating from the stream leaving the reaction zone the catalyst particles inactivated by sulfur-containing carbon deposits and passing to a desorption zone in which the deactivated catalyst contacts a strip-gas to remove volatile deposits from the catalyst; separating the desorbed catalyst particles from the stream leaving the desorption zone, conveying them to a regeneration zone where they are regenerated by burning the desorbed, sulfur-containing carbon sediments from the desorbed particles of the desorbed catalyst particles with oxygen-containing gas, separating the catalyst from the regenerated catalyst stream exiting the regeneration zone and returning it to the reaction zone, characterized in that during fluidized catalytic cracking, solid particles other than a molecular sieve-type cracking catalyst, containing a metallic reagent, are added to the cracking catalyst to be fluidized, and a particle mixture of about 10 to about 99.9975% by weight of a molecular sieve type cracking catalyst in which the metallic reagent consists of at least one free or bound metallic element such as magnesium, calcium, strontium or barium and is present in the mixture of particles in an amount suitable for absorbing at least about 50% of the sulfur oxides formed by burnout in the regeneration zone of sulfur-containing carbon deposits; in the presence of this mixture, cracking of the raw material is carried out at a temperature of about 455 ° -650 ° C; the volatile deposits are then desorbed from the mixture of particles after the mixture has left the reaction zone using a water vapor stripper gas at a temperature of about 455 ° -650 ° C and a weight ratio of water vapor to cracking catalyst of about 0.0005-0.025; the desorbed mixture of particles is regenerated at a temperature of about 560 ° -790 ° C; at least about 50% of the sulfur oxides formed by burnout in the regeneration zone of the carbon sludge containing the weights are absorbed into the mixture; the mixture of particles containing the absorbed sulfur oxides is then passed from the regeneration zone to the reaction zone; a gas stream is discharged leaving the regeneration zone containing molecular oxygen and a small amount of sulfur oxides; and the adsorbed sulfur oxides in the form of a sulfur-containing gas are withdrawn from the reaction and / or desorption zone. 2. The method according to claim The process of claim 1, wherein the metal reagent is comprised of at least one free or bound metallic element such as magnesium or calcium. 3. The method according to p. The method of claim 1, wherein the amount of the metal reaction is about 0.1-0.5% by weight, based on the metal, of the above mixture of particles. 4. The method according to p. The process as claimed in claim 1, characterized in that the fluidizable particles are solid containing a metallic reagent deposited on the carrier, the carrier being an amorphous cracking catalyst or a solid essentially inert to the cracking reaction. 5. The method according to p. The process of claim 4, wherein the carrier is silica, alumina, thorium dioxide, and boron trioxide. 6. The method according to p. The method of claim 1, wherein the molecular sieve-type cracking catalyst is used in an amount of about 90-99.9% by weight of said mixture of particles. 7. The method according to p. The process of claim 1, wherein the water vapor is used in an amount corresponding to a water vapor to cracking catalyst ratio of 0.0015-0.0125. io 8. Way according to replies. The process of claim 1, wherein a gas stream containing at least about 0.01% by volume molecular oxygen is withdrawn from the regeneration zone. 9. The method according to p. The process of claim 1, wherein the regeneration zone is discharged into a gas stream which contains less than 600 parts by volume per million parts by volume of sulfur oxides. 10. The method according to p. The process of claim 1, wherein the raw material contains approximately 1 to 4% by weight of sulfur. 11.. The method according to p. The method of claim 1, wherein the metal reactant-containing fluidizable particles are magnesium oxide particles. 12. A cyclic method of fluidized catalytic cracking of a hydrocarbon feedstock containing 0.2-6% by weight of sulfur in the form of organic sulfur compounds, in which the emissions of sulfur oxides in the gas stream leaving the regeneration zone are reduced by cracking the hydrocarbon feedstock in a reaction zone using a molecular sieve type cracking catalyst in a fluid state; separating the catalyst particles inactivated by sulfur-containing carbon deposits from the stream leaving the reaction zone and conveying to a de-strand zone, where the deactivated catalyst is contacted with a waste gas to remove volatile deposits from the catalyst; separating the desorbed catalyst particles from the stream leaving the desorption zone, conveying them to a regeneration zone where they are regenerated by burning the desorbed, non-desorbable catalyst particles, sulfur-containing carbon deposits with an oxygen-containing gas and separating the regenerated catalyst particles from the stream leaving the regeneration zone and returning them to the reaction zone, characterized in that at least one metal from the group consisting of magnesium, calcium, strontium and barium is introduced into the catalyst particles by adding to the process cycle at least one compound of said metal or metals in a liquid form, whereby the metal is introduced in an amount sufficient to absorb at least about 50% of the sulfur oxides formed by burning in the regeneration zone of the sulfur-containing carbon deposits; the cracking of the raw material is carried out at a temperature of about 55,455 ° C to 650 ° C; the volatile deposits of the deactivated catalyst are desorbed at a temperature of about 455 ° C to -650 ° C with a water vapor stripped gas at a weight ratio of water vapor to cracking catalyst of about 0.0005-0.025; The desorbed catalyst is regenerated at a temperature of about 560 ° C to 790 ° C; is absorbed on the catalyst particles containing said metal at least about 50% of the sulfur oxides formed as a result of burnout in the regeneration zone of sulfur-containing carbon deposits, then conveyed from the regeneration zone to the reaction zone of the catalyst particles containing the adsorbed oxides sulfur; a gas stream leaving the regeneration zone containing molecular oxygen and a small amount of sulfur oxides is discharged and the adsorbed sulfur oxides are discharged from the reaction and / or desorption zone in the form of sulfur-containing gas. 13. The method according to p. The process of claim 12, wherein the metal is magnesium and calcium. 14. The method according to p. The process of claim 13, wherein about 0.1-0.5% by weight of metal is incorporated into the catalyst particles. 15. The method according to p. The process of claim 12, wherein the metal compound is a metal salt. 16. The method according to p. The process as claimed in claim 12, characterized in that metal detonates and metal carboxylates having 1 to 20 carbon atoms in the molecule are used as the metal compound. 17. The method according to claim 10, The process of claim 12, wherein the metal compound is magnesium acetoacetate. 18. The method according to p. 12, characterized by that. the steam is used in an amount corresponding to the ratio of the steam to the cracking catalyst 0.0015-0.0125. 19. The method according to claim The process of claim 12, wherein a gas stream that contains at least about 0.01% by volume molecular oxygen is withdrawn from the regeneration zone. 20. The method according to claim A method according to claim 12, characterized in that the gas-stream leaving the regeneration zone is collected which contains at least less than 600 parts by volume per million parts by volume of sulfur oxides. 12, characterized by that. the raw material contains about 1 to 4% by weight of sulfur. FIG. I 9 8 LDD Z-d 2, issue 1086/1400/81, no. 85 + 20 copies Price PLN 100 PL

Claims (21)

Claims 1. A cyclic method of fluid catalytic cracking of a hydrocarbon feedstock containing 0.2-6% by weight of sulfur in the form of organic sulfur compounds, in which the emissions of sulfur oxides in the gas stream leaving the regeneration zone by 833 29 providing the hydrocarbon feed to cracking in the reaction zone using fluidized-type molecular sieve-type cracking catalyst particles; separating from the stream leaving the reaction zone the catalyst particles inactivated by sulfur-containing carbon deposits and passing to a desorption zone in which the deactivated catalyst contacts a strip-gas to remove volatile deposits from the catalyst; separating the desorbed catalyst particles from the stream leaving the desorption zone, conveying them to a regeneration zone where they are regenerated by burning the desorbed, sulfur-containing carbon sediments from the desorbed particles of the desorbed catalyst particles with oxygen-containing gas, separating the catalyst from the regenerated catalyst stream exiting the regeneration zone and returning it to the reaction zone, characterized in that during fluidized catalytic cracking, solid particles other than a molecular sieve-type cracking catalyst, containing a metallic reagent, are added to the cracking catalyst to be fluidized, and a particle mixture of about 10 to about 99.9975% by weight of a molecular sieve type cracking catalyst in which the metallic reagent consists of at least one free or bound metallic element such as magnesium, calcium, strontium or barium and is present in the mixture of particles in an amount suitable for absorbing at least about 50% of the sulfur oxides formed by burnout in the regeneration zone of sulfur-containing carbon deposits; in the presence of this mixture, cracking of the raw material is carried out at a temperature of about 455 ° -650 ° C; the volatile deposits are then desorbed from the mixture of particles after the mixture has left the reaction zone using a water vapor stripper gas at a temperature of about 455 ° -650 ° C and a weight ratio of water vapor to cracking catalyst of about 0.0005-0.025; the desorbed mixture of particles is regenerated at a temperature of about 560 ° -790 ° C; at least about 50% of the sulfur oxides formed by burnout in the regeneration zone of the carbon sludge containing the weights are absorbed into the mixture; the mixture of particles containing the absorbed sulfur oxides is then passed from the regeneration zone to the reaction zone; a gas stream is discharged leaving the regeneration zone containing molecular oxygen and a small amount of sulfur oxides; and the adsorbed sulfur oxides in the form of a sulfur-containing gas are withdrawn from the reaction and / or desorption zone. 2. The method according to claim The process of claim 1, wherein the metal reagent is comprised of at least one free or bound metallic element such as magnesium or calcium. 3. The method according to p. The method of claim 1, wherein the amount of the metal reaction is about 0.1-0.5% by weight, based on the metal, of the above mixture of particles. 4. The method according to p. The process as claimed in claim 1, characterized in that the fluidizable particles are solid containing a metallic reagent deposited on the carrier, the carrier being an amorphous cracking catalyst or a solid essentially inert to the cracking reaction. 5. The method according to p. The process of claim 4, wherein the carrier is silica, alumina, thorium dioxide, and boron trioxide. 6. The method according to p. The method of claim 1, wherein the molecular sieve-type cracking catalyst is used in an amount of about 90-99.9% by weight of said mixture of particles. 7. The method according to p. The process of claim 1, wherein the water vapor is used in an amount corresponding to a water vapor to cracking catalyst ratio of 0.0015-0.0125. io 8. Method according to replacements. The process of claim 1, wherein a gas stream containing at least about 0.01% by volume molecular oxygen is withdrawn from the regeneration zone. 9. The method according to p. The process of claim 1, wherein the regeneration zone is discharged into a gas stream which contains less than 600 parts by volume per million parts by volume of sulfur oxides. 10. The method according to p. The process of claim 1, wherein the raw material contains approximately 1 to 4% by weight of sulfur. 11.. The method according to p. The method of claim 1, wherein the metal reactant-containing fluidizable particles are magnesium oxide particles. 12. A cyclic method of fluidized catalytic cracking of a hydrocarbon feedstock containing 0.2-6% by weight of sulfur in the form of organic sulfur compounds, in which the emissions of sulfur oxides in the gas stream leaving the regeneration zone are reduced by cracking the hydrocarbon feedstock in a reaction zone using a molecular sieve type cracking catalyst in a fluid state; separating the catalyst particles inactivated by sulfur-containing carbon deposits from the stream leaving the reaction zone and conveying to a de-strand zone, where the deactivated catalyst is contacted with a waste gas to remove volatile deposits from the catalyst; separating the desorbed catalyst particles from the stream leaving the desorption zone, conveying them to a regeneration zone where they are regenerated by burning the desorbed, non-desorbable catalyst particles, sulfur-containing carbon deposits with an oxygen-containing gas and separating the regenerated catalyst particles from the stream leaving the regeneration zone and returning them to the reaction zone, characterized in that at least one metal from the group consisting of magnesium, calcium, strontium and barium is introduced into the catalyst particles by adding to the process cycle at least one compound of said metal or metals in a liquid form, whereby the metal is introduced in an amount sufficient to absorb at least about 50% of the sulfur oxides formed by burning in the regeneration zone of the sulfur-containing carbon deposits; the cracking of the raw material is carried out at a temperature of about 55,455 ° C to 650 ° C; the volatile deposits of the deactivated catalyst are desorbed at a temperature of about 455 ° C to -650 ° C with a water vapor stripped gas at a weight ratio of water vapor to cracking catalyst of about 0.0005-0.025; The desorbed catalyst is regenerated at a temperature of about 560 ° C to 790 ° C; is absorbed on the catalyst particles containing said metal at least about 50% of the sulfur oxides formed as a result of burnout in the regeneration zone of sulfur-containing carbon deposits, then conveyed from the regeneration zone to the reaction zone of the catalyst particles containing the adsorbed oxides sulfur; a gas stream leaving the regeneration zone containing molecular oxygen and a small amount of sulfur oxides is discharged and the adsorbed sulfur oxides are discharged from the reaction and / or desorption zone in the form of sulfur-containing gas. 13. The method according to p. The process of claim 12, wherein the metal is magnesium and calcium. 14. The method according to p. The process of claim 13, wherein about 0.1-0.5% by weight of metal is incorporated into the catalyst particles. 15. The method according to p. The process of claim 12, wherein the metal compound is a metal salt. 16. The method according to p. The process as claimed in claim 12, characterized in that metal detonates and metal carboxylates having 1 to 20 carbon atoms in the molecule are used as the metal compound. 10 32 17. The method according to p. The process of claim 12, wherein the metal compound is magnesium acetoacetate. 18. The method according to p. 12, characterized by that. the steam is used in an amount corresponding to the ratio of the steam to the cracking catalyst 0.0015-0.0125. 19. The method according to claim The process of claim 12, wherein a gas stream that contains at least about 0.01% by volume molecular oxygen is withdrawn from the regeneration zone. 20. The method according to claim A process as claimed in claim 12, characterized in that a gas-stream leaving the regeneration zone is collected which contains at least less than 600 parts by volume per million parts by volume of sulfur oxides 21. The method according to p. 12, characterized by that. the raw material contains about 1-4% by weight of sulfur. FIG. I 9 8 LDD Z-d 2, no. 1086/1400/81, no. 85 + 20 copies. Price PLN 100 PL