DE957326C - Process for refining crude oil - Google Patents

Description

Process for Refining Crude Oil The present invention relates focus on the conversion of crude oil into more valuable oil products. In particular, relates The invention relates to an improved method of refining oil in which crude oil in a very simplified system with the cheapest engine and engine yields Heating oils and with as little accumulation of. relatively heavy products of little value, such as B. heavy oils, tar and coke is converted. It was previously proposed to distill crude oil first to be in the raw state To separate petrol, gas oils and reduced crude oils, and that separated in this way Catalytically cracking gas oil to produce high octane engine oils. Man also has the reduced crude oil distilled under reduced pressure to get from it in addition Obtaining Feedstock for Catalytic Cracking: Another Process to finish the bike consists of that gasoline is a reforming process subjected, is to increase its octane rating.

These different procedures carried out separately from each other require separate fractionation towers and heating units for each process. In addition, there are many containers for storing the various products between the different procedures are necessary. For example is the manufacture, operation and Maintenance of a vacuum distillation system, which is used for further distillation of the reduced crude oil is used, which is made from the under atmospheric pressure Crude oil distillation is still very expensive.

According to the present invention, at least the crude oil is cracked Main quantity on the whole mildly in a first cracking zone in the presence of a weak one Cracking catalyst, conducts a stream of cracked products and uncracked components of the crude oil from this zone in a fractionation column and separates it there into a Gasoline, a gas oil and a high-boiling residue fraction. The gas oil fraction is catalytically cracked in a second cracking zone in the presence of a strong cracking catalyst and directs the hydrocarbons obtained into the lower part of the fractionation column mentioned one where they are also fractionated. At least the bulk of those for this fractionation and the heat required for the first cracking process is obtained by. at least brings most of the crude oil together with the catalyst in the first cracking zone, after the latter by incineration of the separated during this cracking: carbon-containing deposits has been heated.

You can also use a smaller portion of the crude oil at a significantly higher cost below the cracking temperature of the first zone immediately into the Fractionation zone below the entry point of the hydrocarbon cracking products initiate; and you can also at least with the catalyst in the first cracking zone Introduce the desired cracking temperature and measure its amount so that it is used for Heating of the crude oil in this zone up to the stated temperature and to maintain it this temperature is sufficient during cracking. The amount of cracking of gas oil and higher boiling components of the crude oil in the first zone on the Catalyst deposited carbon is generally at most. 4 weight percent when the catalyst is off for regeneration and reheating is taken from said zone, the lower boiling than the gas oil components of crude oil in this zone will remain unchanged. The catalyst is then separated derives from and derives from the cracked products and the unchanged components of the crude oil the cracked products enter the fractionating column at approximately the same temperature as the cracking temperature.

The catalyst preferably enters at least the second cracking zone preheated to the cracking temperature, and its quantity is expediently so large that that the gas oil fraction to be cracked is cracked into gasoline in contact with it can. The hydrocarbons obtained are then separated from the used catalyst and burns away the carbon-containing deposit from this too, whereby it is heated at the same time. The cracked products of this second zone are about with their cracking temperature in the fractionation column below the entry point of the products from the first zone introduced and co-fractionated.

The temperature in the first cracking zone is preferably about 45o up to 600 ° and the cracking time about 1 to 25 seconds. The catalyst used should have an effectiveness of about 12 to 25% distillate -h loss (DL).

One of the main advantages of the present invention is that the heat for the distillation of the crude oil and also for the cracking process Burning the coal formed on the catalyst during the cracking process is produced. In addition, however, other significant advantages are achieved if the procedure is carried out according to the above information. Heavy products of little Value, such as B. heavy oils or heavy components from the catalytic cycle, can be completely eliminated. A single fractionation tower takes the place of several ones that have previously been used to achieve the same result. All impurities in the crude oil are in the first stage of cracking on the catalyst deposited. Most intermediate storage containers fall path. All crude oil is instantly produced in a single cohesive process processed into oil products, so that a substantial part of the normally occurring There is no loss of heat and process products.

In addition, the need to reform gasoline becomes essential degraded. The full implementation of pitch and high-boiling products too Gasoline and heating oils in the presence of cracking catalysts result in comparison with the cracking of the heavy fractions under non-catalytic conditions substantial increase in the proportion of raw catalytic gasoline as a percentage of the raw gasoline content contained in the gasoline blend of the combined process. This effect is further increased by the fact that the in the raw state Petrol proportions of the total crude oil in the first catalytic cracking stage to some extent Scope has been catalytically reformed so that the octave ratio of the is in the raw state The raw gasoline is significantly improved without any separate reforming is necessary.

It has long been an essential goal in the refining of crude oils been, one to the catalytic. Cracking appropriate amount of gas oil as much as possible from the heavy residue fractions, the large amounts for the cracking catalyst harmful Ash constituents contain, separate. distillation in a low pressure vacuum, propane deasphalting and other operations were used for this purpose. The present invention accomplishes this Aim without the need for such expensive auxiliary devices. The extent, up to the fractions with a given boiling range as overhead distillate in a continuous Flashdes.tillation can be distilled depends on the distillation temperature, the distillation pressure and the amount of residues that are also present. at of the present invention destroys the major minor cracking stage prior to distillation a large fraction of the heavy residues, roughly on the order of 70 to 95 0/0. In addition, the products are mild cracking along with the gasoline fractions and other low molecular weight fractions of the crude oil in the main flash zone the large combination fractionation column is present. The presence of these substances Low molecular weight sets the partial pressure of high boiling hydrocarbons At this point it comes down significantly, which in turn means that high percentages are assumed allows the remaining crude oil components @ ile as overhead distillate in the tower. These Fractions can then be cracked in the second conventional catalytic cracking drum be., using a high-quality catalyst that is proportionate is free from impurities. According to the present invention allows the common Compliance with these features the distillation of fractions with a higher boiling point, than they can be obtained by a separate vacuum distillation stage, d. H. of fractions that boil up to a boiling range of 5.9o to 65o °.

The present invention is based on the conditions., Under those at a relatively high temperature, but in a short period of time in that cracking of the crude oil fraction with the highest boiling point is achieved in the first reactor. This in turn supplies the coal, through whose combustion the heat for the first Crude oil distillation is produced, eliminating the need for heating the plant of expensive furnaces of the crude oil is eliminated at high temperatures. It also enables the special connection catalytic reactions with the intermediate distillation already described of the present invention, the use of extremely low distillation temperatures for the crude oil components and refined products. This again enables in that Reaction vessel for the subsequent catalytic cracking of unusually large parts the remaining products with a high quality catalyst.

It has already been proposed to convert hydrocarbons, especially high-boiling ones, such as residual oils from crude oils and tar or asphalt-like oils Residues of the most varied kinds of these starting materials first through a zone to direct evaporation, deasphalting and breaking the viscosity in which they come into contact with a practically inert, non-catalytic solid material: The hot feed then passes into a fractionation zone from which the Gas oil is passed through a heater into the cracking zone and possibly also a cracking and desulfurization zone is interposed. Here, however, the first zone a non-catalytic filling because the tar or asphalt-like constituents the load on this solid filling result in deposits. Because of this arrangement the heater must be switched on in order to bring the gas oil to the reduction temperature bring. In contrast to this known way of working, the treatment is after present invention initially started with a mild cracking, namely in Presence of a catalyst, which later by burning away the deposited therein Coke is regenerated and reheated. In the same way, according to the invention the used catalyst from the second zone is regenerated and heated, with so much heat is obtained that the heat required for the evaporation of the crude oil and for the cracking of these vapors and the fractionation of the products. will. It follows that the inventive method of operation of the be known is superior in several ways.

There has also already become known a method in which a loading from gas oil first flowing through a furnace and then sequentially up and down is passed through a catalytic cracking zone. This is where all products go from the first cracking zone to the second without any intermediate fractionation.

Furthermore, there is already a method for cracking wax distillates has been proposed in several zones, with an intermediate fractionation column Gas oil is separated. Since this is not the gas oil, but the heavy residues are treated in the second cracking stage, there is also a fundamental difference compared to the present proceedings, including the presence another fractionation column comes after the second stage.

It has also been proposed to separate streams one To introduce the hydrocarbon feed into three successive cracking zones, that the olefinic gas oil fraction must pass through all three zones in sequence, to remove resinous components. All of these working methods that have already become known but have nothing to do with the present invention, their particular advantages set out above.

After the objects and general nature of the present invention have been explained, reference is made to the drawing.

Crude oil is introduced into and into the device through line z divided into two parts. The main part (about 55 to go ° / o) is through line 3 in the preheater 5 passed. The rest on cold crude oil is immediate passed through the line in the lower part of the fractionator i i. Of the The part passed through the preheater 5 can be hot in it through heat exchange Fractions from the fractionator, hot regenerator exhaust, or any another type known in the art to about Zoo to 3i5 °, preferably about 26o to 29o °, to be preheated.

The preheated crude oil emerging from the preheater 5 is mixed in line 13 with hot regenerated, distributed cracking catalyst and passed into the reaction chamber 15 for the first cracking stage. The feed rate of this hot catalyst is a function of its temperature, the preheating temperature of the oil and the cracking temperature desired in the reaction chamber 15. In any case, the catalyst should be present in sufficient quantity to completely evaporate the oil, while the non-evaporable constituents are deposited on the catalyst as coke and around the essentially dry catalyst-oil mixture in the reaction chamber 15 at a temperature of hold about 45o to 59o °. The hot catalyst can expediently be charged at rates which are within the range of about 4.6 to 30.2 kg of catalyst per kg of the total charge fed into the reaction chamber 15, the temperatures of the hot catalyst being about 56o to 62o ° , temperatures which are preferably from about io Lie to 9o ° above the desired in. the reaction chamber 15 g cracking temperature s. If desired, the evaporation can be assisted by the addition of small amounts of steam, about 1 to 5 percent by weight of the feed oil through line 17.

The catalyst used in the first stage cracking is preferred an activated natural clay or other low activity cracking catalyst having a cracking activity of about 12 to 250/0 ", preferably about 15 to 18%, D -f-. L (D + 'L = distillate -I- loss; see Ind. Eng. Chem., Vol. 39 [19471, p. 1140; the D -I- L of high activity cracking catalysts is above 25). An average Particle size of about 50 to IOC), u is appropriate.

The cracking catalyst / oil feed mixture is passed from line 13 to the lower portion of a reaction chamber 15. This chamber 15 is in the form of a substantially vertical conduit with a length to diameter ratio of about 8 to 12: i. The mixture is passed through this line as a suspension with a density of about 0.08 to 0.16 kg / l, which is, however, somewhat greater than the corresponding density of the charge ratio of the solid and vaporous particles. Linear steam velocities of about 3 to 30 m / sec can be used. The reaction chamber 15 should be designed so that the oil vapors are retained therein for a relatively short contact time of about 1 to 25 seconds. With this relatively mild nature of the contact time and the catalyst concentration, the heavy feed components are largely cracked and yield hydrocarbons of the gas oil range which are suitable as feedstocks for further catalytic cracking. No matter what type of gasoline is produced, it has a relatively high octane number. On the other hand, the formation of gas and coke is very moderate; coke deposit on the catalyst is usually less than 4 percent by weight of the oil feed.

The suspension of the catalyst in the oil-1 vapor is passed from the reaction chamber 15 into a separation system 19 for gaseous and solid substances, which can consist of a series of cyclone separators and / or electrical separators of the usual type. The separated catalyst is withdrawn from system 19 through pipe 21. An inert gas such as B. steam, exhaust gases od. Like. Is injected through line t in order to supply air to the catalyst and to clean it in the usual way. The catalyst is then suspended in air supplied through lines 23 and the suspension is passed through line 25 and grate 27 to regenerator 30 .

In the regenerator 30 , the carbon is burned away from the catalyst loaded with it, which is in the form of a dense fluidized bed bI3o, which is at the top through a horizontal interface L3. is separated by an upper dispersion layer. The apparent density of the mass 1113p can be around 0.08 to 0.17 kg. Catalyst deposits containing carbon are removed by the heat generating combustion. The catalyst is regenerated in this way and simultaneously heated to around 56o to 62o °. Exhaust gases are withdrawn and discharged through line 31 or used in the system for heat exchange. The hot regenerated catalyst is cleaned and returned to line 13 through ventilated rail 33 at the above temperature and rate.

The circulation of the catalyst between the reaction chamber 15 and the regenerator 30 is preferably carried out without the use of slide valves; rather, the U-shaped pipe bends 22 and 34 serve as gas sealing lungs.

Circulation goes through the two U-shaped tubes, one of which each containing a standpipe through which the solids flow downward, one Closure section that forms the: bent part of the U-tube and in which the pressure is higher than in any other part of the system above this section and in your relatively little gas is required for ventilation, and a higher one Section through which the solid components flow upwards into the other vessel and in which additional gas is introduced in regulated amounts to increase the speed regulate the flow of solids between the vessels Animals. This transport gas becomes a substantial part above the bottom section of the U-tube introduced so that an underlying portion for effective sealing solid constituents in the highest possible density, which form a seal for the gas and which Prevent gases from flowing back from one vessel to the other.

In the drawing, the separator ig and the regenerator 3o represent the two vessels. Standpipe 21, U-bend 22 and pipe 25 are the standpipe section, sealing section and upward-leading section through which the solid components flow from separator ig to regenerator 30. Standpipe 33, U-bend 34 and the pipes 13 and 15 are the corresponding parts for the backflow of the solid components from the regenerator 30 to the separator ig. The normal direction of flow of the solids is caused by a pressure differential in each of the U-shaped conduits 13, 15 such that the total pressure exerted on the solids in the downward section or standpipe section 21 or 33 is the total. pressure exerted in the upwardly leading section 25 or 13. This in turn is achieved in that the density of the whirled up solid components in at least one of the upwardly leading sections 13 and 25 is significantly lower than the density in the relevant section 33 or 21 and by regulating the ceiling pressure in the vessels ig and 33, and differences to compensate in the amount of the catalyst layers located therein.

The U-bends 22 and 34 below the points where the gases or Vyerden introduced vapors, contribute to the build-up of the driving force for the circulation of the solid constituents not with and essentially serve as gas sealing pipes, there, through the downward sections of the seal develop pressure from: the pressure drop is compensated in the upward leading part of the seal. The extent of the Pressure difference between the upper and lower part of the U-bends 22 and 34 is by their height and the density of the suspended solid components contained therein certainly. This pressure difference, measured from the gas inlet point downwards to to the bottom of the U-bend, is held at a value greater than that of is sufficient to compensate for normal pressure fluctuations, so that a sufficient safety factor is available.

The heat developed in regenerator 30 , along with the heat developed in second regenerator 70 , is sufficient to vaporize and crack the preheated feed in reactor 15 and distill the vapor effluent from reactor 15 in fractionation tower ii.

In addition to coke, substantial amounts of inorganic ash constituents are deposited on the catalyst in the reaction chamber 15. In this way, the chamber 15 acts as a highly effective purification stage for the material to be cracked in the second catalytic cracking stage described below. However, these inorganic deposits deactivate the catalyst, and such deactivation cannot be reversed by regeneration by burning off. Therefore, the catalyst from the first stage must be replaced by fresh one, and at a relatively high rate, based on the crude oil fractions high boiling point. However, if the speed is related to the total crude oil charge, it can be kept within low limits, about 0.06 to 0.3 kg of fresh catalyst per hl of the total crude oil charge. The fresh catalyst can be brought into the regenerator 30 through line 35, while corresponding amounts of used catalyst are withdrawn through line 37.

Oil vapors separated by the separator ig are passed through the line 39 into the fractionation tower ii, into which the cracked products from the second cracking stage, as will be described further below, are introduced. The temperature in the lower part of fractionator ii is regulated in that, as described above, part of the cold crude oil feed is fed through line g. In this way the temperature in the lower part of the fractionation tower ii below the gas oil collecting device 41 can easily be kept at about 37o to 425 ° in order to remove the heaviest raw and cracked components in the form of about 59o to. To collect 65o ° boiling fraction; this fraction is returned through line 43 to reactor 15 to be completely cracked therein. If necessary, you can also do one. Subtract part or all of the 01 in line 43 through line 45 and recover it as heavy fuel oil. A fuel oil fraction with a boiling point between about zoo and 29o to 315 ° is recovered through line 47, and a heavy crude gasoline fraction with a boiling range from 120 to 200 ° is withdrawn through line 4g.

Gasoline and carbonic hydrogen gases are discharged as overhead distillate through line 51 and passed through a cooler 53 to a separator 55 for gaseous and liquid substances. Liquid gasoline is taken from line 56 and gas from line 59. Additional gasoline can be prepared by removing butane from the fractionator overhead and polymerizing the C4 fractions It may also be desirable to subject the gasoline product to thermal or catalytic reforming, hydroforming or other refining treatments appropriate to the octane number of the gasoline to improve.

Gas oil boiling between about 29o and 35 ° and 59o and 65o ° is withdrawn from the collecting tray 41 and passed through line 57 to the second catalytic cracking reactor 6o. Hot regenerated cracking catalyst is added from line 61 at a temperature and in an amount sufficient to preheat the oil to cracking temperature and to sustain the cracking reaction. This amount can be about 5 to 25 kg of catalyst per kg of oil in line 61 at a catalyst temperature of about 565 to 62o ° and a cracking temperature in the reaction chamber 6o of about 43o to 54o °. The catalyst is preferably a standard highly active cracking catalyst, e.g. B. Alumina silica gel with a content of about io to 2o weight percent alumina and an average particle diameter of about 5o to. ioo, u. Under fluidized bed conditions, the amount of catalyst in the reactor 6o can be about 2 to 5 19, preferably about 3 to 4 kg of catalyst per kg of the oil to be cracked in one hour. Gas and steam velocities of about 0.15 to 1.5, preferably about 0.6 to 1.2 m / sec, at pressures of about 0 to 7 kg / cm 2, preferably about 0.35 to 1 kg / cm2, work.

Any common catalytic cracking and catalyst regeneration system, z. B. with fixed or movable layers or suspensoid or flowing procedures, is applicable in the second cracking stage of the process. According to a preferred embodiment however, according to the present invention, a dense phase system is more fluid Substances that correspond to the system described in the first stage. The main difference between the two systems explained is the use of the dense phase Cracking reactor 6o with dense phase or a bottom outlet for solids in place the tubular reaction chamber arranged for upward flow 15 of the first cracking stage. Longer cracking times and stronger cracking are due to this Kind achieved in the second stage.

The reaction chamber 6o of the second stage and the regenerator 70 are connected by two U-shaped pipes suitable for circulating the solid components. The ventilated standpipe 63, the U-bend 65 and the upwardly leading section 67 form the conduit through which the catalyst flows from the reaction chamber 6o to the regenerator 70 in approximately the same way as it is with regard to parts 21, 22 and 25 with air being supplied through lines 69. Carbonaceous deposits are produced by the catalyst among others. Conditions burned off as described above with respect to regenerator 3o; Exhaust gases are discharged through line 71. The regenerated catalyst is returned from the regenerator 70 through the vented standpipe 72, the U-shaped pipe 73 and the line 61, preferably through a conventional distribution funnel 75 mounted in the lower part of the reaction chamber 6o.

The cracked oil vapors are passed through line 76 into the fractionator i i, preferably in its lower part, returned where, as described above, in distillates, cycle material for the second stage (line 57) and in the cycle to be used residue products (line 43) are fractionated. The loading of the cracked product in the lower part of the fractionation system supports the separation high quality oil from the heavy soil fraction. These pure fractions will be better passed to the reaction chamber 6o than into the chamber 15 of the first stage.

The system shown in the drawing allows numerous modifications to. In order to prevent excessive catalyst deactivation in the first stage In many cases it may be desirable to desalinate the crude oil to make it inorganic To remove impurities. For this purpose conventional methods, e.g. B. washing with water; with subsequent emulsification and electrical precipitation, Deashing of the solvent, etc., can be applied. In the first crack stage of the However, the present invention is an ash content of 1.4 to 8.6 kg of ash per hl Crude oil is perfectly acceptable.

In the first stage, other catalysts can be used than the special listed can be used. For example, a magnesia-silica catalyst is available for this purpose useful. Instead of two different catalysts in the first and second cracking stage to use the catalyst withdrawn from the second stage can be used as a catalyst can be used for the first stage. For this purpose one can use the catalyst from the regenerator 7o through line 77 into the first stage reaction chamber pass and fresh catalyst through line 79 into the second stage.

While a regenerator was shown as the first stage, in which the flowing substances form a dense phase, a tubular one can take its place Regenerator, which is essential for high throughput speeds simultaneous flow of gases and solid components is suitable. In this manner the amount of catalyst required in the first stage can be reduced significantly. If the volatility of the gasoline produced is too low, a small one can be used Branch heavy crude petrol fraction through line 8o from line 49 and in the regenerator 6o used as the second stage for further cracking into products return with a lower boiling point. As already mentioned above, the manufactured Gasoline is subjected to a reforming or hydroforming process, to improve its octane rating. In. In this case, both cracking stages can be used keep lower temperatures of about 4q.o to 5oo ° regardless of the Quality of the products as much raw gasoline as possible in the catalytic cracking stages obtain. The nature of the raw gasoline can - in the reforming or hydroforming stage, which is particularly effective for this purpose. The whole product from the reforming process can be returned to the flash zone of the fractionation plant i i be to the To obtain heat and a separate fractionation tower to save.

Claims (11)

PATENT CLAIMS: i. Process for refining crude oil, characterized in that that at least the major part of the crude oil is on the whole in a first cracking zone in the presence of a weak crack catalyst, the ly sator cracks the one stream gently the cracked products and uncracked components of the crude oil from this zone into one Fractionation column leads and there in a gasoline, a gas oil and a high boiling point The residue fraction is separated by the gas oil fraction in a second cracking zone catalytically cracking in the presence of a strong cracking catalyst and thereby the obtained Hydrocarbons in the lower part of the fraction mentioned renierkolonne and passes there is also fractionated, at least the majority of which is used for this fractionation and thereby the heat required for the first cracking gains; that at least one Brings the bulk of the crude oil together with the catalyst in the first cracking zone, after this by incineration of the carbonaceous substances deposited during this cracking Deposits have been heated up. 2. The method according to claim i, characterized in that that the temperature in the first cracking zone is about q.5o to 600 °, the cracking time about 1 to 25 seconds, and that the catalyst has an efficiency of about 12 to 25% distillate -f- loss (D -I- L). 3. The method according to claim i and 2, characterized in that a smaller part of the crude oil at a considerably below the cracking temperature of the first zone immediately into the Fractionation zone below the entry point of the hydrocarbon cracking products is initiated. q .. Method according to claims i to 3, characterized in that the catalyst in the first cracking zone at least at the desired cracking temperature is initiated and its amount to heat the crude oil in this zone up to the said temperature and to maintain this temperature during the Cracking is sufficient. 5. The method according to claim i to q., Characterized in, that in the cracking of gas oil and higher boiling components of the crude oil in the first zone at most q. Percent by weight of carbon deposited on the catalyst before this for regeneration and reheating from the mentioned zone is taken, the lower boiling than the gas oil constituents of the crude oil remain unchanged in this zone. the catalyst from the cracked products and separates the unchanged constituents of the crude oil and the cracked products, for example with the cracking temperature in the fractionating column. 6. The method according to claim i to 5, characterized in that the catalyst in the second cracking zone at least occurs preheated to the cracking temperature and that its amount is so large that the gas oil fraction to be cracked can be cracked into gasoline in contact with it, whereupon the obtained hydrocarbons are separated from the used catalyst, from this the carbonaceous deposits burns away and him at the same time thereby reheating, and that the cracking products of this second zone for example with their cracking temperature in the fractionation column below the inlet parts which introduces cracked products from the first zone and fractionates there. 7. Procedure according to claim i to 6, characterized in that the highest-boiling fractions over boil about 600 to 65o ° and that they are practically completely out of the fractionating column be returned to the first cracking zone. B. Method according to claims i to 7, characterized in that the catalyst in the first cracking zone is an activated one natural tone is. G. Process according to Claims 1 to 8, characterized in that the catalyst is used in finely divided form and that a fluidized bed is produced therefrom with the hydrocarbons flowing through to be cracked, the density of which is 0.06 to 0.32 and that has a steam speed of 3 up to 30 m / sec is passed through the cracking zone. ok Procedure according to Claims i to 9, characterized in that a smaller amount of the crude oil into the fractionation zone and the main amount after preheating to about zoo to 3i5 ° is introduced into the cracking zone, where it is treated with a catalyst with an efficiency of about 12 to 18o / o distillation + loss (D -I- L) a fluidized bed with one density forms from 0.06 to 0.32 and is heated to the cracking temperature in contact with it will; that after cracking the gas oils and higher-boiling fractions of this main amount the cracked products in the fractionation zone below the entry point of the mentioned introduces smaller amount of crude oil and there as well as the mentioned smaller amount of crude oil into a lighter and a heavier gasoline fraction, gas oil and about 600 to 65o ° separates the high-boiling residues and the high-boiling residues in the first zone and the gas oil in the second zone at 48o to 5q.o ° in contact with such an amount by 25 to 100 ° higher than the said cracking temperature preheated silica-alumina catalyst with an effectiveness of over 251 / o distillate -f- Loss (D + L) cracks that the cracking temperature reached in this second zone and a considerable part of the gas oil turned into gasoline is cracked, whereupon part of the catalyst is removed by burning away the Coal deposited on it is regenerated and reheated and then again returns to the second cracking zone, -from which the cracked products with the fracking temperature into the fractionation column below the entry point of the cracked products from the Enter the first zone, whereupon the sought gasoline fractions are obtained from this column wins. Process according to Claim ro, characterized in that at least part of the aforementioned heavy fuel fraction is also passed through the second cracking zone. Contemplated publications: USA. Patent Nos 2,507,523, 2,488,032, 2 56 0 511, 2 46 o 404 2,477 042;. French patent specification No. 950 8I1.