EP0432235B1 - Process for the production of improved octane numbers gasolines - Google Patents

Abstract

PCT No. PCT/BE90/00028 Sec. 371 Date Mar. 22, 1991 Sec. 102(e) Date Mar. 22, 1991 PCT Filed Jun. 8, 1990 PCT Pub. No. WO90/15121 PCT Pub. Date Dec. 12, 1990.Process for producing gasolines having improved RON and MON which consists in subjecting the LCO, HCO and CLO obtained by catalytic cracking of a heavy hydrocarbon feedstock, to a hydrogenation treatment and subjecting the obtained products to a new catalytic cracking and then recovering hydrocarbons boiling in the range of gasolines.

Description

The present invention relates to a process for producing gasolines with a high octane number. In particular, the present invention relates to the production of gasoline having an improved RON and MON, starting from heavier hydrocarbon feeds, originating from the catalytic cracking in a fluidized bed of vacuum gasels, deasphalted oils and residues.

The catalytic cracking process in a fluidized bed of heavy hydrocarbon feedstocks such as vacuum gas oils, is a well-known process in particular for producing gasolines. It is also essential to produce gasolines with a high octane number due to the upcoming removal of lead additives. There is therefore a growing need to obtain, at the start of these same charges, gasolines having an octane index or RON indices (octane index "Research") and particularly MON (octane index "Engine") improved.

It is well known to subject loads of heavy hydrocarbons such as gas oils, vacuum gas oils or the like to catalytic cracking in a fluidized bed (FCC), so as to form light products rich in olefins and hydrocarbons boiling in the range of species. We also form heavier products, in particular light "cycle oil" (LCO) boiling between 221 and 350 ° C, heavy "cycle oil" (HCO) boiling between 350 and about 400 ° C and clarified oils ( CLO) boiling at a temperature above 400 ° C. Most often HCO and CLO are used as fuel components, while the LCO is subjected to a hydrogenation treatment to improve its characteristics with a view to using it as a component of diesel for example.
It has also been described that it was advantageous to subject only the LCOs thus hydrogenated to an FCC treatment in the presence of a partially deactivated FCC catalyst, which of course requires complicated arrangements for the catalytic cracker which must be used.

Patent EP 184669 describes a process for the production of gasoline with a high octane content in which a catalytic cracking of a heavy carbo-metallic oil is carried out, an LCO fraction is recovered which is subjected to a hydrogenation step and the entire hydrogenated fraction is introduced into an FCC unit.

US Patent 4,426,276 describes many processes for converting or upgrading crude oil; these processes are characterized in that a residual oil fraction is catalytically cracked and that the resulting high boiling fraction is then hydrocracked. According to a particular embodiment, after the hydrocracking step, the possibility of recycling the liquid products having a boiling temperature of between 204 and 315 ° C. is described by reintroducing them successively in the flash separation and cracking steps. catalytic.

The Applicants have now found that there was a way of considerably improving the RON and MON of the gasolines produced by catalytic cracking of heavy hydrocarbons.

The object of the present invention is a process which makes it possible to produce gasolines having improved RON and MON starting from heavy hydrocarbon charges.

The present invention also aims at a process for producing gasolines having improved RON and MON, from hydrogenated LCO, HCO and CLO.

• a. Soumettre à un craquage catalytique en lit fluidisé, une charge d'hydrocarbures lourds, par mise en contact avec un catalyseur fluide de craquage catalytique, pour former des produits gazeux, des hydrocarbures bouillant dans la gamme des essences, des LCO, des HCO et des CLO;
• b. Séparer le catalyseur des produits formés;
• c. Séparer et envoyer les LCO, HCO et CLO formés, dans un autre réacteur dans lequel on les soumet à une hydrogénation à une température comprise entre 320 et 420°C, à une pression comprise entre 30 et 200 bar et en présence d'un catalyseur d'hydrogénation pour former des hydrocarbures gazeux, des hydrocarbures bouillant dans la gamme des essences et des hydrocarbures bouillant à une température supérieure à environ 221°C;
• d. Séparer les hydrocarbures bouillant à une température supérieure à environ 221°C, formés à l'étape (c);
• e. Soumettre les hydrocarbures bouillant à une température supérieure à environ 221°C, formés à l'étape (d) à un craquage catalytique en lit fluidisé, le réacteur étant de préférence différent de celui de l'étape (a).
• f. Récupérer les hydrocarbures bouillant dans la gamme des essences formés à l'étape (e), ayant des meilleurs RON et MON.

The process of the present invention for producing gasolines having improved RON and MON is characterized in that it comprises the steps which consist in:

• at. Subject to a catalytic cracking in a fluidized bed, a charge of heavy hydrocarbons, by contacting with a fluid catalytic cracking catalyst, to form gaseous products, hydrocarbons boiling in the range of gasolines, LCOs, HCOs and CLO;
• b. Separate the catalyst from the products formed;
• vs. Separate and send the LCO, HCO and CLO formed, in another reactor in which they are subjected to hydrogenation at a temperature between 320 and 420 ° C, at a pressure between 30 and 200 bar and in the presence of a catalyst hydrogenation to form gaseous hydrocarbons, hydrocarbons boiling in the range of gasolines and hydrocarbons boiling at a temperature above about 221 ° C;
• d. Separating the hydrocarbons boiling at a temperature above about 221 ° C, formed in step (c);
• e. Subject the hydrocarbons boiling at a temperature above about 221 ° C, formed in step (d) to a catalytic cracking in a fluidized bed, the reactor preferably being different from that of step (a).
• f. Recover boiling hydrocarbons in the range of gasolines formed in step (e), having better RON and MON.

The present invention is also described with the aid of the accompanying drawing, in which FIG. 1 represents a schematic diagram of the process of the invention.

Referring to FIG. 1, a charge of heavy hydrocarbons is introduced via line 10, which may consist of gas oil, vacuum gas oil or other similar charges. This charge is introduced into the FCC reactor 20 in which it is brought into contact with a fluid catalytic cracking catalyst introduced through line 22. The charge and the catalyst are mixed and driven upwards. The catalyst is made up of fine particles so that it acts as a fluidized bed. The reaction takes place in reactor 20, the catalyst falls by gravity and is recovered for regeneration via line 18 and is regenerated in reactor 16, while the various products of the catalytic reaction which include gaseous hydrocarbons, hydrocarbons boiling in the range of gasolines, LCOs, HCOs and CLOs are recovered via line 24, to be sent to a separator (25) to separate the gaseous and light products leaving via line 26, heavier products leaving through line 28. The light products recovered through line 26 consist of hydrocarbons boiling in the range of gasolines.

The heavy products leaving via line 28 consist of LCO boiling between 221 and 350 ° C, HCO boiling between 350 and 400 ° C as well as CLO boiling at a temperature above 400 ° C.

According to an embodiment of the process of the invention, the LCO, the HCO and the CLO are successively separated and they are subjected separately afterwards to a hydrogenation treatment. According to another embodiment of the method of the invention, the LCOs, HCOs and CLOs are subjected together to a hydrogenation treatment. Whatever the mode of execution chosen, the current leaving via line 28 is mixed with hydrogen coming from one or the other source defined below and the mixture of charge and hydrogen via line 29 in the hydrogenation reaction zone 30 in the presence of a hydrogenation catalyst at a temperature between 320 and 420 ° C and under a pressure between 30 and 200 bar. Generally, the hydrogenation catalyst is in the form of a fixed bed, in the reaction zone 30. The charge to be hydrogenated passes through the catalytic bed maintained under hydrogenation conditions as stated above. The effluent product is withdrawn from the reactor 30 via the line 31 and is introduced into the separator 32, in which the gaseous products and products boiling in the range of gasoline are separated on the one hand by the line 33. that is to say at a temperature below 221 ° C, and on the other hand via line 34, the hydrogenated products boiling at a temperature above 221 ° C. These boiling hydrocarbons are subjected to a temperature above 221 ° C., to a new catalytic cracking in a fluidized bed, in a reactor (36) preferably different from the first reactor (20). The hydrocarbons treated by the line (38) are recovered and separated in the separator (40) between products boiling in the range of gasolines and heavier products, containing LCO, HCO and CLO which are recycled to the reactor d hydrogenation 30 by the pipe (42), while recovering gasolines having an improved RON and MON by the pipe (44).

The Applicant has unexpectedly found that by subjecting all of the hydrogenated products having a boiling point above 221 ° C. taken together or separately to an FCC, the total quantity of gasolines formed by the process is increased and the RON and MON of the species formed were considerably increased.

It is understood that the process of the invention can be adapted to the numerous modes of execution of a catalytic cracking in a fluidized bed, the essential being to resubmit the hydrogenated hydrocarbons and boiling above 221 ° C., to a treatment. from FCC.

The Applicant has moreover observed that subjecting the hydrogenated LCOs, HCOs and / or CLOs to a new FCC makes it possible to obtain gasolines with better RON and MON. Contrary to what is taught in the state of the art, it is not essential to limit the FCC reaction of LCOs, HCOs and / or CLOs with partially deactivated catalysts, in order to obtain the good gasoline yields, but, and this constitutes an essential element of the invention, it is absolutely necessary to contact it with a fresh FCC catalyst to obtain gasolines having a better RON and MON. In the case where there is no availability of a second FCC reactor, the hydrocarbons leaving via line 34 can be recycled to the first FCC reactor (20) in admixture with the charge of VGO (vacuum stars), but the results from the RON and MON point of view of the species obtained are slightly lower than those obtained with the mode of execution of the method presented above.

It is also conceivable to introduce the hydrogenated LCOs, HCOs and / or CLOs into a second transport reactor ("aim") mounted in parallel with the reactor reserved for the normal load of the FCC (20). According to another operating mode, the FCC (20) can be used to crack the loads (normal heavy and hydrogenated LCO, HCO and / or CLO) by campaign. The two previous examples are only to be considered as an example of implementation in practice, the main thing remaining being to contact the LCO, HCO and / or CLO fillers hydrogenated with a fully active catalyst.

It is obviously not necessary to treat the hydrocarbons having a lower boiling point, since they are recovered as petrol either by line 33, or by line 26.

There are a large number of catalysts suitable for use in catalytic cracking processes, in particular amorphous silica-alumina, silica-magnesia, catalysts of the crystalline zeolite type such as faujasite or other analogues, such as Y zeolites dispersed in a matrix of silica and another inorganic oxide or in an alumina matrix. The zeolites can also be used pure with or without zeolitic promoters of the ZSM-5 or silicalite type.

Generally the matrices consist of silica-alumina in a 90-40 / 10-60 ratio, in which the zeolites are dispersed. Zeolites are generally of the Y zeolite type exchanged with rare earths or of the ultrastable type (the mode of dealumination being variable).

Promoters can also be added in an amount of 5 to 15% by weight of the zeolite used. The catalytic cracking is generally carried out at temperatures between 480 and 550 ° C and preferably between 510 and 530 ° C; at pressures between 1 and 4 bar and preferably between 1 and 2 bar.

The hydrotreating catalyst is preferably sulfur resistant. Most are Group VI and Group VIII metal catalysts deposited on an alumina or silica-alumina support and other similar supports. Most of the time, we use a Nickel-Molybdenum catalyst deposited on alumina or silica-alumina.

The hydrogenation operating conditions are a temperature between 270 and 500 ° C, a pressure between 30 and 200 bars and preferably between 60 and 120 bars, an LHSV between 0.5 and 5 and a H₂ / HC ratio included between 500 and 50,000 NL / L.

The following examples are given to better illustrate the present invention, but without limiting its scope.

Examples 1 to 3 .

A charge consisting of VGO, the characteristics of which are given in the following table, was subjected to catalytic cracking under the following operating conditions: T ° 520 ° C Pressure atmospheric Food 600 gr / hour Catalyst / load (wt / wt) 6 100% VGO Base charge Density 0.9240 Sulfur (%) 1.8375 Aniline point (° C) 79.2 Refractive index at 50 ° C 1.5024 Aromatics (UV) (millemoles / 100 gr) MONO 55 DI 19 SORTING 18 TETRA 15 PENTA + 1

At the outlet of the catalytic cracking reactor, the boiling products in the range of gasolines, LCOs and HCOs and CLOs were separated. The LCOs, HCOs and CLOs were subjected to hydrogenation separately in the presence of a Ni-Mo catalyst and under the conditions indicated in Table 1. At the outlet of the hydrogenation reactor, the boiling products in the gasoline range were separated. and those with a boiling point above 221 ° C. The products having a boiling point above 221 ° C. were sent directly to a second catalytic cracking reactor under the conditions indicated in Table 1. The properties of the gasolines produced at the outlet of this latter catalytic cracking reactor are indicated in Table 1.

For comparison, the same load of VGO was subjected to an FCC under the same conditions as those above. The species obtained with this process had a RON of 91.7 and a MON of 78.6. It is noted that the method of the invention allows a gain of 3 points in MON which is very advantageous.

Example 4.

A charge consisting of VGO, the characteristics of which are given in Table 1 and of a recycled stream formed of hydrogenated LCO, was subjected separately to catalytic cracking under the following operating conditions: T ° 520 ° C Pressure atmospheric Food 600 gr / hour Catalyst / load (wt / wt) 6

At the outlet of the catalytic cracking reactor, the boiling products in the range of gasolines, LCOs and HCOs and CLOs were separated. The HCOs were subjected to hydrogenation at a temperature of 390 ° C. and under a pressure of 120 bar, at an LHSV of 0.6. At the outlet of the hydrogenation reactor, the products boiling in the gasoline range were separated from those having a boiling point above 221 ° C. and they were sent directly to a second catalytic cracking reactor. The properties of the gasolines produced at the outlet of this latter catalytic cracking reactor are shown in Table 1.

Claims (7)

1. Process for producing improved RON and MON gasolines characterized in the following steps:

   a. A heavy hydrocarbon feedstock is subjected to a fluidized bed catalytic cracking by contacting it with a fluid catalyst of catalytic cracking in order to produce gaseous products, hydrocarbons boiling in the range of gasolines, LCO, HCO and CLO;

   b. The catalyst is separated from the generated products;

   c. LCO, HCO and CLO are separated ans sent into another reactor where they are subjected to a hydrogenation step at a temperature comprised between 270 and 500°C, at a pressure comprised between 30 and 200 bars and in the presence of a hydrogenation catalyst in order to produce gazeous hydrocarbons, hydrocarbons boiling in the range of gasolines and hydrocarbons boiling at a temperature higher than about 221°C;

   d. Hydrocarbons from step (c) boiling at a temperature higher than about 221°C are separated;

   e. Hydrocarbons from step (d) boiling at a temperature higher than about 221°C are subjected to a fluidized bed catalytic cracking in a reactor which is preferentially different from step (a);

   f. Hydrocarbons from step (e) boiling in the range of gasolines with improved RON and MON are recovered.
2. Process according to Claim 1 characterized in that the hydrogenated LCO produced at step (c) is subjected to a FCC.
3. Process according to Claim 1 characterized in that the hydrogenated HCO produced at step (c) is subjected to a FCC.
4. Process according to Claim 1 characterized in that the hydrogenated CLO produced at step (c) is subjected to a FCC.
5. Process according to Claim 1 characterized in that the mixture LCO, HCO and CLO from step (c) are subjected to a FCC.
6. Process according to any one of Claims 1 to 5 characterized in that the LCO, CLO, HCO recovered from step (c) are subjected together or separately to a hydrogenation treatment at a temperature comprised between 320 and 420°C.
7. Process according to any one of Claims 1 to 6 characterized in that the LCO, CLO, HCO recovered from step (c) are subjected together or separately to a hydrogenation treatment under a pressure comprised between 60 and 120 bars, at a LHSV comprised between 0.5 and 5 and with a ratio H₂/HC comprised between 500 and 50,000 NL/L.

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