PL145514B1 - Method of carrying out a catalytic cracking process in fluidized bed - Google Patents

Abstract

A method for operating a fluid catalytic cracking unit comprising a regeneration zone and a reaction zone with a relatively reduced temperature in the regeneration zone while processing a high-coke-making hydrocarbon feedstock having a 50 volume percent distillation temperature greater than about 500 DEG F (260 DEG C) which method comprises contacting at conversion conditions the feedstock in a reaction zone with a fluidizable mixture of regenerated cracking catalyst and low-coke-make non-catalytic solid particles, comprising a refractory inorganic oxide, in a ratio of low-coke-make solid particles to cracking catalyst from about 1:100 to about 10:1, the low-coke-make solid particles having a surface area of less than about 5 m<2>/g and a coke making capability of less than about 0.2 weight percent coke in the ASTM standard method for testing cracking catalyst by microactivity (MAT); separating the resulting hydrocarbon products from the mixture of deactivated cracking catalyst and low-coke-make solid particles; recovering the hydrocarbon products; passing the mixture of cracking catalyst and low-coke-make solid particles to the regeneration zone for generation by removal of coke; and passing the resulting regenerated mixture of cracking catalyst and low-coke-make solid particles from the regeneration zone to the reaction zone to contact the feedstock as described above whereby the regeneration zone temperature is maintained at a reduced temperature as compared to an equivalent operation without the use of the low-cake-make solid particles while simultaneously not reducing the coke burning capacity of the regeneration zone or affecting the operation of the reaction zone.

Description

The present invention relates to a method of performing fluidized bed catalytic cracking in an apparatus comprising a reaction zone and a regeneration zone with a reduced temperature in the regeneration zone during processing of a high-coke-making feed stream. More particularly, it is an object of the invention to lower the maximum temperature achieved in the regeneration zone of the fluidized bed catalytic cracking process without reducing the amount of coke burned therein, so that as an admixture to the cracking catalyst, continuously fluidizable particles are circulated. low coke-making capacity, having a specific surface area less than about 5 m / g and producing less than about 0.2 wt% coke, when determining ASTM standard method for microactivity testing and fluidized bed cracking catalyst (MAT), sufficient to obtain the ratio of the amount of solid particles with low coke-making capacity to the amount of cracking catalyst from about 1: 100 to about 10: 1, as a result of which the regenerator temperature is reduced by about 6 to about 139 ° C without adversely affecting the course of the process in the zone reaction * In patents US Pat. No. 2,889,269 and No. 2,894,902 disclose methods in which a finely divided catalyst and inert, fluidizable solid heat transfer particles are circulated through a fluidized bed reactor-regenerator system to remove heat from the fluid bed. regenerator. These methods are used primarily in connection with the hydroforming of naphtha carried out in the fluidized bed and are not related to the feed streams with high coke-making capacity and the reduction of the regenerator temperature without disturbing the reactor operation and the coke combustion capacity in the regenerator. The patent claims neither disclose nor describe the problems relating to the process of the invention, as well as the use of fluidizable solid particles with a low coke-making capacity having a specific surface area of less than about 5 m / g and a coke-making capacity of less than about 0, 2% by weight of coke for the determination ASTM standardized method to test the microactivity of a cracking catalyst (MAT) in a fluidized bed catalytic cracking process, as a result of which the temperature of the regeneration zone is kept at a lower level without affecting the coke combustion capacity. Generator, relative process flow in the reaction zone. U.S. Patent No. 4,289,605 describes a catalytic cracking process carried out in a fluidized bed in which a metal-containing hydrocarbon feed stream is brought into contact with a mixture of an active cracking catalyst and inert porous solids. . Preferred inert porous solid particles are characterized by having at least 50% of the pore volume composed of pores with a diameter of at least 100 and having a specific surface area of about 10 to 15 m / g. A preferred type of inert porous solid particle is roasted porcelain clay. The main purpose of inert solid particles with large pores is the selective capture of large particles, characteristic of the gray metal and compounds that are subject to coking during the Conradson test. adversely affecting the course of the reactor process, nor does it suggest that the key to this is the use of low-coke-making solid particles which have a specific surface area of less than about 5 and / g and produce less than about 0.2% coke by weight. This is a standardized ASM method to test the microactivity of cracking catalysts (MAT), which is added in certain amounts in addition to certain amounts of catalyst needed to achieve the purpose of the reactor, and not in place of the catalyst. 116 202A, a mixture of St. suitable for catalytic cracking, consisting of a solid cracking catalyst and a diluent containing a selected Al20t or a selected Al20t or selected Al20t in combination with one or more high temperature resistant non-organic compounds, the alumina diluent having a specific surface area of 30 -1000 m / g and a pore volume of 0.05-2.5 cnr / g * The main purpose of the diluent with a large surface area is to allow the proper operation of the catalyst system even when there is a lot of metal on the surface of the catalyst. These applications do not involve temperature control in the regenerator and do not provide for the circulation of low-coke-making solids that have a specific surface area of less than about 5 m / g and produce less than about 0.2 wt.% Coke when determined by a standardized method. ASTM tests the microactivity of cracking catalysts (MAT) in order to reduce the temperature of the regeneration zone without affecting the course of the process in the reaction zone. with a catalyst from which the coke has been removed. Thus, for example, U.S. Patent Nos. 2,819,951, 3,990,992, and 4,219,442 describe fluidized bed catalytic cracking processes using dual zone regenerators with cooling coils mounted in a second zone. These cooling coils must always be filled with refrigerant and thus always remove heat from the regenerator, even during start-up, when such a discharge is particularly undesirable, because the typical metal composition of these coils is such that the coils are free of refrigerant. coolant to keep them at a relatively low temperature would be damaged by exposure to the high temperature of the regenerator (up to about 732 ° C). In addition, the cooling coil must reduce the temperature of the regenerated catalyst that circulates to the reaction zone. Thus, to keep the temperature of the reaction zone constant, additional amounts of catalyst must be circulated, which in turn produces more coke, further reducing the yield of valuable liquid products. a fluidized bed in an apparatus comprising a regeneration zone and a reaction zone during processing of a feed stream of high coke making hydrocarbons having a distillation temperature of 50% by volume above 26 ° Cf characterized by the fact that the feed stream contacts the reaction zone under endothermic conditions coke-making transformation with fluidizable heated mixture of regenerated cracking catalyst and low-coke-make solid particles, non-catalyst containing the low-melting inorganic oxide, the ratio of the amount of solid particles low-coke-make-up to cracking catalyst amounts are from about 1: 100 to about 10: 1, and these low-coke-make steels have a specific surface area of less than about 5 m / g and a coke-making capacity of less than about 0.2 wt. for the determination of the standard ASTM method for testing the microactivity of the cracking catalyst (MAT), then the obtained hydrocarbon products are separated from a mixture of coke-containing deactivated cracking catalyst and solid particles with low coke-making capacity, the hydrocarbon products are recovered, the mixture is sent of cracking catalyst and low-coke-make solids to the regeneration zone to reheat and carry out regeneration by exothermic coke combustion, and the resulting reheated and regenerated mixture of cracking catalyst and low-coke-make solids is sent from the regeneration zone to the reaction zone to contact the feed stream As stated above, whereby the temperature of the regeneration zone is kept lower than the corresponding operation carried out without the use of low-coke-make solids, without reducing the coke-burning capacity of the in the regeneration zone or adversely affect the course of the process in the reaction zone. Another embodiment of the process according to the invention includes a method of conducting catalytic cracking in a fluidized bed of a feed stream of high coke-producing hydrocarbons having a distillation temperature of 5096 vol. above 26 ° C by contacting the feed. stream under endothermic cracking conditions with a circulating, heated solid particle catalyst, whereby the feed stream components are converted into lower boiling hydrocarbons in the reaction zone with simultaneous cooling the catalyst and the deposition on it of the deactivating carbon contamination, regeneration of the catalytic cracking activity of the contaminated catalyst by burning carbon deposits therefrom in the regeneration zone under exothermic conditions which make the catalyst and regeneration zone reach an unacceptable or undesirable maximum temperature, and then circulating the reheated and regenerated catalyst from the regeneration zone to the reaction zone, characterized in that the maximum temperature reached in the regeneration zone is lowered without reducing the amount of coke burned therein in such a way that, as an admixture to the catalyst cracking. At the same time, fluidizable particles with low coke-making capacity are circulated, which contain a non-melting inorganic oxide and have a specific surface area of less than about 5 m2 / g and which produce less than about 0.2% coke by weight A standardized ASTM method to test the microactivity of a fluidized bed cracking catalyst (MAT), wherein these solid particles are present in an amount sufficient to produce a low coke-make solid particle ratio to a cracking catalyst amount of from about 1: 100 to about 10: 1, as a result of which the regeneration temperature is reduced by from about 6 to about 139 ° C, without simultaneously adversely affecting the course of the process in the reaction zone. the characteristics of the catalyst and low-coke-make solids and the operating conditions are described below in the course of discussing all aspects of the process of the invention. according to the invention. Other types of equipment may also be suitable for use in the process of the invention. Fluidized bed wide-scale catalytic cracking is used to convert starting materials such as vacuum gas oils and other heavy oils into lighter and more valuable products. This fluidized bed catalytic cracking process involves contacting the starting material in the reaction zone, whether it is gaseous oil or other oil, with a finely divided or particulate solid catalytic material which is behaves like liquid when mixed with gas or vapor. This teterial has the ability to catalyze the cracking reaction and is coated on the surface with coke, which is a by-product of the cracking reaction. Kbks consists of hydrogen, carbon and other materials such as sulfur and reduces the catalytic activity of fluidized bed catalytic cracking catalysts. Typically, the fluidized bed catalytic cracking unit also includes special coke removal devices for the catalytic cracking catalyst, so-called regenerators or regenerators. conditions that the coke is oxidized and a significant amount of heat is released. Some of this heat escapes from the regenerator together with the exhaust gas consisting of excess regeneration gas and gaseous coke oxidation products, while the rest of the heat leaves the regenerator with the regenerated, i.e. relatively coke free, catalyst. Regenerators operating at pressures above atmospheric pressure are often equipped with energy recovery turbines, in which the exhaust gas escaping from the regenerator expands and some of the energy released during expansion is then recovered. the totalizer in the form of a fluidized bed continuously circulates from the reaction zone to the regeneration zone and then back to the reaction zone. The catalyst in the fluidized bed, in addition to its catalytic action, also serves as a carrier for transferring heat from zone to zone. The catalyst leaving the reaction zone is referred to as a spent catalyst, that is to say, partially deactivated by coke deposition on the catalyst. The catalyst from which the coke was essentially removed is referred to as a regenerated catalyst. The rate of conversion of the feed stream of materials in the reaction zone is controlled by adjusting the temperature, the activity of the catalyst, and the catalyst content (i.e., the ratio of catalyst to oil). ). The more commonly used method of controlling temperature is to regulate the rate of circulation of the catalyst from the regeneration zone to the reaction zone, thereby increasing the catalyst / oil ratio. This means that if it is desirable to increase the conversion rate, the flow rate circulating in the fluidized bed of the catalyst from the regenerator to the reactor is increased. Due to the fact that the temperature in the regeneration zone under normal operating conditions is much higher than the temperature in the reaction zone, this increase in the flow of the catalyst from the hotter regeneration zone to the cooler reaction zone causes the temperature of the reaction zone to increase. for carrying out the catalytic cracking process in a fluidized bed, they influence the coke content on the spent catalyst. Generally speaking, the higher the molecular weight, the higher the carbon content in the Conradson test, the higher the heptane insoluble residue, and the higher the carbon to hydrogen ratio, the higher the coke content on the spent catalyst * Also Bound nitrogen levels, such as those found in shale oils, increase the coke content on the spent catalyst * Processing of increasingly heavier feedstocks, in particular processing of deasphalted oils, or processing of residues from crude oil distillation under atmospheric pressure, 145 514 5 common periods as a mazout, it increases all of these factors and therefore increases the concentration of coke on the spent catalyst. This increase in the amount of coke on the spent catalyst causes the regenerator to burn more coke per kilogram of circulating catalyst izator. In conventional fluidized bed catalytic cracking equipment, heat is removed from the regenerator in the flue gas and primarily in the hot stream of regenerated catalyst. Just the coke content on the spent catalyst will increase the temperature of the regenerator. However, there are temperature limitations that a fluid bed catalytic cracking catalyst can withstand without serious deleterious effects on the activity of the catalyst. Generally speaking, for a commercially available catalyst of this type, the temperature of the regenerated catalyst is usually kept below 760 ° Cf due to the very severe loss of activity above about 760 to 788 ° C. In order to allow more coke to burn in the regeneration zone, one In order to keep the maximum temperature below about 76 ° C, it has hitherto been advisable to use cooling coils installed in or in communication with the regeneration zone. The cooling coils associated with the regeneration zones of the fluidized bed catalytic cracking equipment must necessarily be filled with coolant at all times and are considered to be the weak link in the overall fluidized bed catalytic cracking process. transfer of heat from the regeneration zone to the reaction zone without simultaneously affecting the course of the process in the reaction zone or limiting the coke combustion capacity in the regeneration zone. and low-coke-make solids, fluidizable particle sizes, are brought into contact with a feed stream of hydrocarbons, the catalyst and low-coke-make solids are then regenerated and recycled. it is highly desirable to circulate catalyst particles which crack the feedstock by their catalytic cracking activity, but which also produce coke on their surface, as a by-product of this process with a different class of particles which show very little tendency to produce coke. The working criterion for selecting the latter class of particles to be used in the process of the invention is their ability not to contribute significantly to the formation of additional coke on the mixture of solids and catalyst particles above the coke content that would be deposited on the catalyst particles if present. they collapsed in an environment of reaction alone. and the latter class of particles will be hereinafter referred to as low-coke-make steels. The method of the invention comprises the process of continuously catalytically converting a wide variety of hydrocarbon oils into lower molecular weight products while simultaneously maximizing the production of high-value liquid products, enabling the production of high-value liquid products. skipping vacuum distillation and other costly operations such as hydrotreating if necessary. Preferred feed streams of materials for use in the process of the invention include residual hydrocarbon oil or any other feed stream of hydrocarbons having a distillation temperature of 50% by volume above about 260 ° C. The term "residual hydrocarbon oil" includes not only those predominantly hydrocarbon mixtures which are liquid at room temperature, but also those mainly hydrocarbon mixtures which appear as asphalts or tar at ambient temperature but which liquefy when heated to the temperature of the mixture. Another essential element of the process of the invention is the fluidizable fluidized bed catalytic cracking catalyst. In general, it is preferred to use a catalyst having an effective level of cracking activity, providing high conversion levels and yields at low reactor residence times. This catalyst may be introduced into the process in its original or in a non-original form, e.g. used previously. Any hydrocarbon cracking catalyst having the above-mentioned characteristics may be used. A particularly preferred class of catalysts comprises catalysts having a pore structure into which particles of the feed material may enter for adsorption and / or contact with active catalytic sites within or adjacent to the pores. Various types of catalysts are available within this classification, including, for example, layered silicates such as smectites. While the most widely available catalysts within the framework of this classification are the well-known zeolite-containing catalysts, the present invention also envisages the use of zeolite-free catalysts. Preferred zeolite catalysts may contain any zeolite, natural, semi-synthetic or synthetic, alone or in mixture with other materials that do not significantly impair the performance of the catalyst, provided that the resulting catalyst has the above-mentioned activity and pore structure. the catalyst is a mixture, it may contain zeolite bound to or also dispersed in a porous support consisting of a high temperature resistant inorganic oxide. In such a case, the catalyst may, for example, contain about 1% to about 6096, more preferably about 1 * to about k0% fa most preferably about 5% to about 25% by weight, based on the total weight of the (anhydrous) zeolite catalyst, while the rest of the catalyst is made of a porous, heat-resistant inorganic oxide, alone or in combination with any of the known adjuvants to promote or suppress desired or undesirable reactions. attention to the information in the articles "Refinery © talysts Are a Fluid Business" and "Tfeking Cat Crackers Work on a Varied Diet" which appeared in Chemical Week magazine on July 26, 1978 and September 13, 1978, respectively. here the descriptions contained in the mentioned publications. Most of the zeolite components containing zeolite catalysts will be components known to be useful in fluidized bed catalytic cracking processes. They are typically crystalline aluminosilicates, typically composed of tetrahedron-coordinated aluminum atoms bound in a crystal structure to adjacent silicon atoms by oxygen atoms. However, as used herein, the term "zeolite" includes not only aluminosilicates, but also substances in which the aluminum has been partially or completely replaced, for example by gallium, phosphorus and other metal atoms, and substances in which all or part of silicon has been replaced by germanium. The substitution of titanium and zirconium also comes into play. Most zeolites are produced or occur naturally in sodium form, so that sodium cations are associated with electronegative places in the crystal structure. Sodium cations make zeolites inactive and much less stable under conditions. processing of hydrocarbons, in particular against the action of high temperatures. Accordingly, ions can be exchanged in the zeolites, and when the zeolite is part of the catalyst blend, the exchange of ions may take place before or after the addition of the zeolite component to the blend. Suitable cations suitable for replacing sodium in the zeolite crystal structure include ammonium (decomposing to hydrogen), hydrogen, rare earth metals, alkaline earth metals, etc. Various possible ion exchange methods and cations which can be incorporated into the zeolite crystal structure are well known to those skilled in the art. 145 514 9 Examples of naturally occurring zeolites - crystalline aluminosilicates, which can be used as or for incorporation into a catalyst in the method of the invention include: faazite, mordenite, clinoptilot, chabasite, analytite, erionite, such as also levinite, roofiardite, paulingite, noselite, feriorite, heulandite, scolecite, stibite, harmotome, filipsite, bervsterite, flaritic, datolite, gmelinite, kaumnite, leucite, lapisurite, scaplite, mesolite, phtholite, nepheline, ratholite, sodalite, sodalite examples of synthetic zeolites - crystalline aluminosilicates, which can be used as or also included in the catalyst composition in the method according to The invention consists of synthetic zeolites which are the subject of the US patents listed below: zeolite X - No. 2,382,244, zeolite Y - 3,130,007 and zeolite A - No. 2,382,243, as well as zeolite B-No. 3,008,308 * zeolite D - Canadian patent No. 661 981, zeolite E - Canadian patent No. 614 495, zeolite F - No. 2 996 358, zeolite H - No. 3 010 789, zeolite J - No. 3 001 369, zeolite L - Belgian patent description No. 575 117, zeolite M - No. 2 995 423, zeolite 0 - No. 3 140 252, zeolite Q - No. 2 991 151, zeolite S - No. 3 054 657, zeolite T - No. 2 950 952, zeolite W - No. 3 012 853, Z zeolite - Canadian Patent No. 614,495 and Omega Zeolite - Canadian Patent No. 817,915. ZK-4HF, alpha, beta and ZSM zeolites are also useful. Rmadto is useful as the zeolites disclosed in U.S. Patent Nos. 3,140,249, 3,140,253, 3,944,482, and 4,137,159, fragments of which are included herein for reference. according to the invention. This includes, in particular, natural faazite and zeolite X and zeolite Y. Commercial zeolite catalysts with supports containing various metal oxides and combinations thereof, including, for example, silicon dioxide, alumina, magnesium oxide, and mixtures thereof and mixtures thereof, are available. aluminum oxides, for example as described in U.S. Patent No. 3,034,948. For example, any of the zeolite molecular sieve fluidized bed cracking catalysts that are suitable for the production of gasoline from gas oils may be selected. products obtained under reduced pressure. However, some advantages may be obtained by a judicious choice of catalysts which show marked metal resistance. A metal resistant zeolite catalyst is disclosed, for example, in U.S. Patent 3,944,482, in which the catalyst contains 1-4% by weight of rare earth exchanged zeolite and the remainder is a high temperature resistant metal oxide. Catalysts having a particle size distribution in the range of from about 5 to about 160, and more preferably from about 30 to about 120 µm, are generally preferred. The catalyst may also include one or more combustion promoters, which are useful in the next stage of catalyst regeneration. Cracking of the residual oils causes significant coke deposition on the catalyst, which coke reduces the activity of the catalyst. Thus, in order to restore the activity of the catalyst, the coke is burned off in a regeneration step where the coke is transformed into flue gas containing carbon monoxide and / or carbon dioxide. A number of substances are known which, when introduced in small amounts into a cracking catalyst, promote the transformation of coke into carbon dioxide. Such promoters, normally used in effective amounts ranging from traces up to about 10 or 20% by weight of catalyst, may be of any type that generally promotes coal combustion under regeneration conditions, or may have some selectivity for completing the combustion C0 »W The process of the present invention produces a stream consisting of a slurry of hydrocarbon feed to the process, catalyst and low-coke-making solids. The resulting slurry is generally brought up to allow the desired hydrocarbon conversion to take place. ft * It is also noted that dilution streams, such as steam or gaseous light hydrocarbons, may be introduced from the bottom of the reactor riser to achieve the maximum evaporation rate of the feed stream. 10 145 514 evaporate as much of the feed stream as possible and efficiently mix the feed stream of hydrocarbons, catalyst and low-coke-make solid particles so that the resulting mixture flows as a diluted slurry with a gradual motion. The coke-making process is separated from the hydrocarbons, and preferably all or at least a substantial portion of the hydrocarbons are suddenly separated from the catalyst and low-coke-make solids. This separation may be carried out in any convenient way and may include the use of cyclones and similar devices. Preferably, the above-described slurry should be transported in a portion defined as the reactor riser, which is approximately vertical, as opposed to horizontal, and has a length to diameter ratio of at least about 10, more preferably about 20 to 25 or even more. If this part is in the shape of a tube, this round reactor riser may have a uniform diameter over its entire length, or its diameter may increase smoothly or stepwise along the reactor in order to maintain or vary the velocity in the flow path. Generally, the configuration of the reactor is such as to provide a relatively high flow rate and dilute the slurry of catalyst and low-coke-making solids, so for example, the average speed in the riser pipe of the reactor will typically be at least about 7 to 62 m / s, and more typically at least about 10 # 7 m / s. This diameter can be as high as about 16.8 m / s or about 22.9 m / s or even higher. The achievable speeds in the riser tube of the reactor will generally be sufficient to prevent significant build-up of the catalyst bed at the bottom or in other parts of the riser, so that the load on the riser tube of the reactor can be kept below about 64.1 or 80.1 kg. / m5 and below about 32 kg / m5 respectively on the upstream side (i.e. bottom) and the downstream side (i.e. top) of the reactor riser pipe. production of coke and products As a stream in a controlled and sustained direction resulting from the elongation of the reaction zone. However, this does not imply that the flow must be strictly linear. As is well known, there can be some turbulent flow and "skid" of the catalyst and low-coke-making solid particles, in particular in certain ranges of vapor velocities and some catalyst loads. catalyst to reduce slippage and back-mixing of the stream. This more preferred form of catalyst is one which rapidly separates a substantial portion or all of the vaporized cracking products from the catalyst and low coke make solids at one or more points along the riser tube and preferably separates essentially all vaporized cracking from the catalyst. catalyst and low-coke-make solids at the end of the riser tube on the downstream side of the reactor. The preferred process conditions according to the invention are described below. In our process, the preheating of the feed stream is advantageously limited so that this feed stream of raw materials can absorb more of the heat from the catalyst and the low-coke-make solid particles, while the catalyst and the solid particles with low coke-making capacity, heats the feed stream of raw materials to the transition temperature, while minimizing the consumption of external fuels for heating the feed stream of raw materials. Thus, as long as the nature of the feedstock feed allows it, it may be introduced at ambient temperature, while the heavier feed streams may be introduced at preheat temperature to about 316 ° C, typically about 93.3 ° C to about 260 ° C. C, although the use of higher preheating temperatures is not entirely excluded. The temperature of the catalyst and the low-coke-make solids introduced into the riser tube of the reactor may vary widely, for example, from about 593 ° C to about 927 ° C, more preferably from about 49 ° C to about 371 ° C. 145 The fluids of the hydrocarbon feed stream to lower molecular weight products can be carried out at a temperature of about 454 to 76 ° Cf as measured at the reactor outlet. Depending on the selected temperature and the properties of the hydrocarbon feed stream, all of this stream may evaporate in the reactor riser, or not. Although the pressure in the reactor may vary from about 68.9 to about 482.6 kFa, this is the preferred range for use The pressure is from about 103.4 to about 379.2 kho. The residence time of the feed vapors and products in the riser tube of the reactor can range from about 0.5 to about 6 seconds. The residence time depends on the feed stream, the type and amount of catalyst and low coke making solids, temperature and pressure. A person skilled in the field of hydrocarbon processing will readily select the appropriate residence time in the reactor in order to obtain the benefits provided in the process of the invention. to oil is maintained in the range of about 1: 1 to about 30: 1 catalyst weight per feed weight, while at the same time there are low-coke-make solid particles sufficient to obtain a ratio of low coke-make solid part weight to cracking catalyst masses from about 1: 100 to about 10: 1. Generally the combination of catalyst to oil ratio, low coke make solids ratio, temperatures, pressures and residence times should be such as to ensure significant transformation of the feed stream residual hydrocarbons. An advantage of the process according to the invention is that very high conversion levels can be achieved in a single pass; Thus, for example, the conversion rate may be greater than 60% and may range up to about 90 ° C and above. Preferably, the above-mentioned conditions are maintained at levels sufficient to provide degrees of conversion ranging from about 60% to about 9096 and more preferably from about 65 ° C to about 85 ° C. The higher conversion rates are calculated by subtracting from 100% the percentage obtained by dividing the volume of the fresh feed liquid by 100 times, the volume of the coated product boiling at and above 221.1 ° C. These significant conversion rates can and usually are associated with high coke forming efficiencies, such as, for example, about 3.5 to about 2% by weight based on the fresh feed. The method of the invention preferably comprises desorbing hydrocarbons from the spent catalyst and solid particles. low coke making capacity after separation from product vapors. Those skilled in the art know suitable desorbing agents and the conditions for desorbing the spent catalyst. A significant degree of conversion of hydrocarbon oil into lighter products by the method of the invention results in a correspondingly high coke formation yields and coke deposition on the catalyst and low coke-forming solids requiring some attention during their regeneration. In order to maintain the desired activity of the catalyst, it is desirable to regenerate it under conditions of time, temperature and atmosphere such that it is possible to reduce the amount of carbon remaining on the catalyst to about 0.2596 weight or less. Accordingly, the amounts of coke which have to be burned off in the regeneration zone during the processing of residual oils are considerable. Some of the coke will inevitably deposit on the low-coke-make solid particles and the burning of this low-coke-make solids in the regeneration zone will also be referred to as regeneration, although combustion is not an actual regeneration of catalytic activity. The term coke as used in the description of the process of the invention is understood to include any unvaporized hydrocarbons remaining on the catalyst and low coke make solids after carrying out the desorbing operation. Regeneration of the catalyst and low-coke-make solids by burning off the coke deposited on the catalyst and the low-coke-make solids during the feed stream conversion may be performed at any suitable temperature ranging from about 593.3 ° C to about 871 ° C. The hot catalyst stream from the regenerator can be recycled to the regenerator inlet to ensure complete combustion of the coke in the regenerator. has cf until the regenerated solid particle mixture is brought into contact with the fresh feed stream. E When converting the residual hydrocarbon oil to the conversion stages of the present invention, a significant amount of heat is produced in the regenerator during the burning of coke. and replenishing heat losses from the reactor. The heat from the regenerator is transferred to the reactor via the circulation of low-coke-make solid particles and the catalyst. Thus, the temperature of the regenerator can be controlled by varying the proportion of the amount of low-coke-make solids circulating between the regenerator and reactor to the amount of catalyst. This makes it possible to independently control the temperature of the regenerator by controlling the amount of low-coke-make solids in the circulating solids mixture low-coke-make-up particles and catalyst. For a discussion of one embodiment of the process of the present invention, refer to the accompanying drawing. The feed stream of residual hydrocarbons enters the riser tube of reactor 2 via line 1 and contacts the mixture of regenerated catalyst and low-coke-make solids supplied via line 13. The resulting combination of hydrocarbons, catalyst and low-coke-make solids passes through. generally upward through the ascending tube of reactor 2f in which most of the hydrocarbon conversion takes place and enters the actual reactor 4, which has an interior space 3. This interior space 3 serves as a separation area in which the catalyst and the constant particles with low coke-making capacity separates from hydrocarbon vapors. The spent catalyst and low-coke-making solids are collected at the bottom of reactor U and are then removed from it via line 7. LCR level test, record and control device 20 maintains the flow rate in line 7 based on the differences. The pressures measured by pressure sensors 18 and 19. Changes in the amount of particles in the U reactor will cause changes in the differential pressure. The regulator 20 will maintain the desired amount of particles by controlling the regulating valve 21. Hydrocarbon vapors containing the entrained fine catalyst particles and solid particles with a low coke-making capacity pass into the cyclone 5 and the hydrocarbon vapors containing solid particles at a lower concentration are removed from the reactor 4. via conduit 6. The captured solid particles return to the inner space 3 from the bottom of the cyclone 5. As is well known in fluidized bed cracking, there can be many cyclones and cyclones can be multi-stage, where the gas phase from the cyclone dust collector It passes to the second stage cyclone separator. The spent catalyst and solid particles with a low coke-making capacity are brought into contact via line 7 with the air (or oxygen) used for regeneration supplied via line 8. A mixture of air, spent catalyst and low-capacity solids manufacturing The coke disintegration is introduced into the regenerator 10, which has an internal space 9 through conduit 8. The conditions in the regenerator 10 are such that the air containing oxygen and coke react chemically to produce exhaust gas, resulting in the catalyst and solid particles with a low production capacity. The coke is relatively freed from the coke. 145 51 13 The resulting regenerated catalyst particles and the low-coke-making solid particles collect the seed of the middle part of the regenerator 10 and are then removed via line 13 and introduced into the riser tube 2 As described above. 13 is a control valve 14 to regulate the flow of the regenerated catalyst and low-coke-making solids in response to the temperature measurement, and the TC 15 controller receives and transmits the corresponding signals via items 16 and 17 * Although the temperature sensor 16 is shown in the upper position end of reactor 4 near the dust of the cyclone 5, any suitable temperature associated with the reactor 4 may be selected for direct control of the valve 14. in this field, a more complete understanding of the process according to the invention and obtaining the maximum benefit that can be obtained from it. The data in equation (1) below can be used to estimate the temperature of the regeneration zone or regenerator of the fluidized bed catalytic cracking apparatus, What will be produced by circulating from the regeneration zone to the reaction zone of low-coke-make solids, known heat specificities and coke-making tendencies: regenerator final temperature * (A) (B) (C)? Lector ^^ The regenerator temperature prediction from the above equation is based on the assumption that all independent operating variables of the fluidized bed catalytic cracker remain constant, while low coke-making particles are continuously added to the circulating catalyst stock. These independent operating variables include the temperature of the feed stream, composition of the feed stream, temperature of the reactor, the combustion rate of the carbon oxide in the regeneration zone, the pressure of the apparatus, and the type of catalyst. For the purposes of this calculation, the only change to the fluid bed catalytic cracker operation is the addition of low coke make solids to the circulating catalyst lane. By keeping all other independent operating variables constant the effect of low make solid particles is apparent coke to lower the temperature of the regeneration zone. Of course, in industrial practice, once the temperature of the regeneration zone has been brought down to the desired level, the above-mentioned independent operating variables would normally be adjusted to take advantage of the reduced temperature of the regeneration zone. The final regenerator temperature is a function of the quantity and specific heat of the low-coke-making solids. , the heat of the inherent fluidized bed catalytic cracking catalyst, the regenerator temperature prior to the introduction of the low-coke-make solids, and the coke-making tendency of these low-coke-make solids, and the catalytic fluidized-cracking catalyst. in equation (1), individual symbols mean: a, 2fes. C * W * 1 CLCMS + DLCMS (* LCMS * * * cat14 145 514 where: C ^, ^ is the fraction by weight of solid particles low coke-make-up capacity in the circulating fluidized bed catalytic cracking catalyst inventory after addition of low-coke-make solids; regenerator is the temperature of the regenerator of the fluidized bed catalytic cracking apparatus prior to the introduction of the low coke-make solids; Treaktor is the temperature of the heavy phase fluidized bed reactor reactor; IV t is the coke increment per catalyst (% by weight of coke on the catalyst spent in fluidized bed catalytic cracking minus% by weight of coke on regenerated fluidized bed catalytic cracking catalyst); and Dirug is the coke build-up on low-make solids (# by weight of low-make solids coke exiting the reactor minus the carbohydrate coke on low-make solids exiting the regenerator). Examination of the word "A" above shows that steels with a low coke-making capacity with a high specific heat should be more effective, as it would be less expensive for the material to achieve a given reduction in regenerator temperature. Even if the low-coke-make steels have a low specific heat, the process is still feasible, but more low-coke-make solids would be needed to achieve the same effect. that solid particles with a low coke-making capacity are more desirable, which show little or no coke build-up because the additional coke amounts produced by the low-coke-making solids result in increased heat generation in the fluidized bed regenerator of the catalytic cracking, which could reduce to zero or even prevent the expected reduction of the regenerator temperature. Because the heat demand of the reactor of the fluidized bed catalytic cracking device is practically constant and the device operates in a state of thermal equilibrium under constant operating conditions, it is coke deposited on solid particles with low production capacity coke will displace the coke that would previously be generated by circulating the catalytic cracking catalyst in a fluidized bed. As a result, coke deposited on solids with a low coke-making capacity will reduce the number of particles. and feed to the reactor riser per kilogram of feed, specified. As the ratio of the amount of catalyst to the amount of oil. Thus, the rate of conversion observed in the reactor of the fluidized bed catalytic cracker will be reduced. This is a strong incentive to select low-coke-make solids that produce little or no coke to provide the least harmful effect to the reactor performance of the fluidized bed catalytic cracking apparatus. In order to illustrate the preferred embodiments of the process according to the invention, and not as an exaggerated limitation of the generally broad scope of the process according to the invention set forth in the appended claims. The tests involved cracking a mixture of gaseous oil from low pressure distillation and atmospheric distillation residues. Both the gaseous oil from the vacuum distillation and the atmospheric distillation residues were obtained from domestic crude oil and the blend contained 8.4% by volume liquid residues after atmospheric distillation. Table 1 shows the results of the analysis of the components of this feed stream # Table 1 Gaseous oil from low pressure distillation 899 0.93 0.29 0.2 282 335 365 400 446 499 559 580 99 1 Atmospheric temperature 955 1.49 8.5 34 357 426 476 526 573 at 57 * 57 43 Specific weight, kg / m Sulfur,% w / w Carbon determined in the Conradson test,% w / w Nickel + vanadium, ppm Distillation, ° C Initial boiling point 5 # 4 (# 609 * 80 * 95 * End of boiling point Recovered,% Distillation resistance,% Tests were performed in the riser tube of the reactor with upflow, using a zeolite fluidized bed cracking catalyst. a 1124 kFa overpressure reactor. residue from distillation under atmospheric pressure. These treatments were carried out at a catalyst to oil ratio of 6.7, a feed temperature of 227 ° C, and a reactor temperature of 521 ° C with a resulting regenerator temperature of 774 ° C. The conversion of the fresh feed was 81,796 by volume liquids to produce gasoline of 62,596 by volume liquids having an octane number of 92.7. The yield of coke formation was 5.6 wt% of the feed stream. The second test was performed as a comparative test and illustrates one embodiment of the method of the invention. These trials were carried out with the same feed stream containing the atmospheric distillation residue as in the first trial. These trials were carried out with a catalyst to oil ratio of 6.5, a feed temperature of 246 ° C, and a reactor temperature of 520 ° C. In this test, the circulating catalyst stream entering the reactor also contained 9 parts by weight of low-make inorganic oxide solids per part by weight of low-make solids, i.e. the ratio of catalyst to low-make solids. coke 9: 1 «16 145 514 The steels of low coke-making inorganic oxide were alpha-Al20 particles, f having a specific surface area less than about 1 m / g and whose particles produced 0% by weight of carbon on the alpha-A consumed For the determination, ASTM Standard Method for Fluid Cracking Catalyst Testing in the Microactivity Test (MAT), the lifetime ratio of solids (catalyst and low-coke-making solids) to oil was 7.5. The regenerator temperature was only 725 ° C compared to 742 ° C for the first trial. The feed conversion rate was 80.5% by volume liquids to produce 62.7% by volume gasoline having an octane number of 92.5. The coke forming yield was 5,696 by weight. Note that the feed temperature in the second run was 246 ° C while the feed temperature in the first run was 227 ° C, or 18 ° C lower. It is well known that this type of fluid bed catalytic cracking apparatus operation is characterized in that an increase in the feed stream temperature causes an increase in the regenerator temperature. Accordingly, with the lower feed temperature in the second trial, one would expect a correspondingly lower regenerator temperature, which would lower the regenerator temperature even more. For ease of comparison, the results of both tests are presented in Table 2. Table 2 Summary of test results Operating conditions Configuration Ratio of catalyst weight to solid particles with low coke-making capacity Feed stream temperature, ° C Reactor pressure (kft positive pressure) T Reactor temperature, ° C Catalyst to oil ratio, kg / kg. Catalyst to solid particles with low coke making capacity, kg / kg. Regenerator temperature, ° C. -,% vol. liquid petrol,% vol. liquid, recirculating light gas oil, fi vol. of liquid purified dispersion oil,% vol. liquid coke, wt.% W / total yield, vol. of liquid of liquids Octane number of gasoline Conventional 100/0 227 124 521 6.7 - 742 4.1 12.7 15.6 62f5 11.1 7.2 5.6 109.1 81.7 92.7 tetalizer / solid particles 90/10 246 124 520 6.7 9 725 4.0 12.2 14.3 62.7 12.4 7.1 5.6 109.2 80.5 92.5 Fb The higher comparison shows that the use of solid particles with low coke making capacity with the cracking catalyst resulted in the formation of the same amount of coke as on the catalyst itself. The conversion efficiency and product quantities are comparable for both trials. From the point of view of operation, the unique advantage demonstrated by the test with the addition of solid particles with low coke-making capacity was the ability to operate the regenerator at a temperature of 725 ° C, which is 17.2 ° C lower than in the example or control test. As already mentioned above, the lower regenerator temperature obtained helps maintain the activity of the catalyst in the cracking process, provides increased flexibility in selecting operating conditions, and eliminates or at least reduces the need for external cooling devices for the catalyst regenerator. The regenerator temperature can also be independently controlled by varying the proportion of low coke make solids in the catalyst mixture plus low coke make solids * Example II. This example is intended to show the results of testing various fluidizable solids in a test which is substantially equivalent to the above-described ASTM Standard Method for Testing a Cracking Catalyst by a Microactivity Test (MAT). The spruce used in this example is based on the use of a narrow fraction of Mid-Continent crude gas oil, which gas oil had the properties listed in Table 3 «Table 3 Properties of Mid-Continent crude oil gas specific weight, kg / no. Sulfur , wt% nitrogen, wt% heavy metals, ppm distillation, ° C initial boiling point 2096 50 * 10% 95% end boiling point 866 0.26 0.03 3 236 305 349 373 413 432 this example was similar to, but not identical to, the ASTM standard raw material specified in the ASTM standard procedure and was selected to copy the ASTT1 standard material. This test involves loading a 4 g particle sample into the reactor and injecting For 75 seconds, 1.3 g of the above-described gas oil was added to a reactor maintained at 482 ° C. The mass ratio of solids to oil by weight is about 3 The mass volume velocity is about 15.4. In the above-described test, samples of alpha-A ^ O * particles, gamma-A1205 particles and roasted kaolin clay particles were tested separately. The characteristics of these three materials and the results of separate tests are presented in Table 4. m2 / g Pore volume cmVg R ~ change% vol Coke on solid particles used% by weight alpha-Al20, gamma-Al20t roasted kaolin clay (3 hours at S71.1 ° C) <1 205 0 0.92 0.0154 7.3 6.6 0 0.32 0.0818 14S 51 * In gamma-A ^O testing, it is a representative of alumina having a specific surface area of 30-1000 m / g and a pore volume of 0.05-2.5 cnr / g, which is disclosed as a diluent for a catalytic cracking catalyst in British Patent No. 2 116 062 # The data in table U shows that gamma-A ^ O * shows a 7.3 # volumetric transformation, accumulates 0.3296 wt coke on the consumed gamma-AlgO * particles and has a Specific surface area of 205 m / g * In the method according to According to the invention, the particles selected to perform the function of solid particles with low coke-making capacity must necessarily produce less than 0.2% by weight of coke on the spent particles for the determination of the ASTM standard method for testing the microactivity of the cracking catalyst (MAT), having a specific surface area of less than about 5 m / g and not significantly affect the process flow in the zone Due to the fact that gamma-A120 accumulated quite a significant amount of coke and showed a tendency to process hydrocarbons, showing the undesirable ability to influence the course of the process in the reaction zone of the fluidized bed catalytic cracker, gamma-Al2O3 did not suitable for use as low-coke-make solids in the process of the invention No. 4,289,605 * The data from Table k show that roasted kaolin shows a transformation of 6.6% by volume, accumulates 0.089% by weight on the spent kaolin clay particles and has a specific surface area of 9 g / g. to fulfill the function of solid particles with low k-production capacity Oxides must necessarily produce less than about 0.2% by weight of coke on the consumed particles for the determination, the standard ASTM method for testing the microactivity of the cracking catalyst (MAT), have a surface area of less than about 5 m / g and do not significantly affect the course of the process in the reaction zone . Due to the fact that the roasted ball clay accumulated a measurable amount of coke, it showed a tendency to process hydrocarbons, thus showing the undesirable ability to influence the course of the process in the reaction zone of the fluidized bed catalytic cracker and had a specific surface area of 9 m 2 / g, the calcined kaolin clay tested is not suitable for use as low-coke-making solid particles in the process of the invention. show that alpha-AlpO shows a minimal conversion of **, 1% by volume, does not accumulate detectable amounts of coke on the alpha-Al ^O ^ consumed when determining the ASTM standard method for cracking catalyst microactivity (MAT) and has a specific surface area less than 1 m / g. To obtain the maximum benefit from the process according to the invention, preferably fluidizable particles of low coke-making capacity should have a surface area of less than about 5 m / g and produce less than about 0.2% by weight of coke, based on the solid particles consumed. low-coke-make-up determination Standard ASTM Method for Fluid Cracking Catalyst Microactivity (MAT) Testing Conversion to spent steels of low coke make-up particles for the determination Standard ASTM Method for Fluid Cracking Catalyst Microactivity (MAT) Testing. about 0.05 wt% coke based on the consumed steels of low coke making capacity in the determination standard ASTM method for testing the microactivity of fluidized bed cracking catalyst (WT) 145 514 19 It must be emphasized that the coke is formed on fluidizable The particulate matter added to regulate the temperature is obviously formed by non-selective cracking of the feed stream and thus has a significant negative effect on the yield structure of the products obtained from the reactor. This negative effect of the solid support material obviously increases with an increase in the amount of coke formed and thus the low coke-making capacity is a basic requirement for both proper operation of the reactor and temperature reduction in the regenerator. ' Claims 1 # A method of conducting catalytic cracking in a fluidized bed of a high coke-producing hydrocarbon feed stream with a distillation temperature of 50% by volume above 26 ° C by contacting the feed stream under endothermic cracking conditions with a circulating, heated, solid particle catalyst where the feed stream components are converted into lower boiling hydrocarbons in the reaction zone with simultaneous cooling of the catalyst and deposition of the deactivating carbon contaminant thereon, restoration of the catalytic cracking activity of the contaminated catalyst by burning carbon deposits therefrom in the regeneration zone under conditions exothermic, and then returning the reheated and regenerated catalyst from the regeneration zone to the reaction zone, characterized in that the maximum temperature achieved in the regeneration zone is lowered will not change increasing the amount of coke burned in it by simultaneous circulation in a mixture with a cracking catalyst, fluidizable solid particles of low coke-forming capacity, containing a non-melting inorganic oxide, with a specific surface area of less than about 5 m / g and a coke formation capacity of less than about 0 29% by weight for the determination, ASTM Standard Method for Fluid Cracking Catalyst Testing in the Microactivity Test (MAT), in an amount sufficient to obtain a ratio of low coking capacity solids to cracking catalyst amount from about 1: 100 to about 10: 1, as a result of which the regeneration temperature is lowered by from about 6 to about 139 ° C, without simultaneously affecting the course of the process in the reaction zone. A process as claimed in claim 1, characterized in that the low coking capacity particles containing alpha-Al ^ O are constantly used. 3. The method according to p. 1, characterized in that the steels used are low coking capacity particles with a specific surface area below approximately 5 m / g and a coke forming capacity below approximately 0.059 seconds by weight of coke based on the mass of solid particles used in the determination, the standardized ASTM method for testing the cracking catalyst in a test microactivities (MAT). 4. The method according to p. The process of claim 1, wherein the steels are low coking capacity particles ranging in size from about 5 to about 2000 µm. 5. The method according to p. The process of claim 1, wherein the mixture of the regenerated catalyst and the low coking capacity solids is introduced into the reaction zone at a temperature of about 649 ° C to about 871 ° C. 6. The method according to p. 1, characterized in that the transformation is carried out under a pressure from about 103 to about 379 kia with a catalyst / oil weight ratio from about 1: 1 to about 30: 1 and at a temperature from about 454 to about 760 ° C. 145 51 ^ Laboratory Printing Department of the People's Republic of Poland. Mintage 100 copies Price PLN 400 PL PL

Claims (6)

1. Patent Claims 1 # A method of conducting catalytic cracking in a fluidized bed of a high coke-producing hydrocarbon feed stream with a distillation temperature of 50% by volume above 26 ° C by contacting the feed stream under endothermic cracking conditions with a circulating, heated, solid particle catalyst as a result, the feed stream components are converted into lower boiling hydrocarbons in the reaction zone with the catalyst being cooled down and the inactivating carbonaceous fouling deposited thereon, restoration of the catalytic cracking activity of the contaminated catalyst by burning carbonaceous deposits therefrom in the regeneration zone under exothermic conditions, and then returning the reheated and regenerated catalyst from the regeneration zone to the reaction zone, characterized in that the maximum temperature achieved in the regeneration zone is lowered not from reducing the amount of coke burned in it by simultaneous circulation in a mixture with a cracking catalyst fluidizable solid particles with low coke forming capacity, containing a non-melting inorganic oxide, with a specific surface area of less than about 5 m / g and a coke formation capacity of less than about 0 29% by weight for determination, ASTM Standard Method for Fluidized Bed Cracking Catalyst Testing in the Microactivity Test (MAT), in an amount sufficient to obtain a ratio of low coking capacity solids to cracking catalyst amount from about 1: 100 to about 10 : 1, as a result of which the regeneration temperature is reduced by about 6 to about 139 ° C, without affecting the course of the process in the reaction zone * 2. The method according to p. A process as claimed in claim 1, characterized in that the low coking capacity particles containing alpha-Al ^ O are constantly used. 3. The method according to p. 1, characterized in that the steels used are low coking capacity particles with a specific surface area below approximately 5 m / g and a coke forming capacity below approximately 0.059 seconds by weight of coke based on the mass of solid particles used in the determination, the standardized ASTM method for testing the cracking catalyst in a test microactivities (MAT). 4. The method according to p. The process of claim 1, wherein the steels are low coking capacity particles ranging in size from about 5 to about 2000 µm. 5. The method according to p. The process of claim 1, wherein the mixture of the regenerated catalyst and the low coking capacity solids is introduced into the reaction zone at a temperature of about 649 ° C to about 871 ° C. 6. The method according to p. 1, characterized in that the transformation is carried out under a pressure from about 103 to about 379 kia with a catalyst / oil weight ratio from about 1: 1 to about 30: 1 and at a temperature from about 454 to about 760 ° C. 145 51 ^ Laboratory Printing Department of the People's Republic of Poland. Mintage 100 copies Price PLN 400 PL PL