JP2509314B2 - Process for petroleum hydrocarbon conversion in the presence of fluidized bed catalyst particles and apparatus for carrying out the process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention is directed to catalytic cracking of heavy hydrocarbons and mild steam cracking of light hydrocarbon inserts in the same reaction zone, at the same time, to reduce olefins, especially 2-4. The present invention relates to a conversion method and a conversion device capable of producing an olefin having carbon atoms.

[Conventional technology and problems]

As is well known, hydrocarbon cracking processes are commonly used in the petroleum and petroleum related industries, and these processes consist in splitting hydrocarbon molecules into smaller molecular weights by increasing the temperature. There are two types of cracking, thermal cracking and catalytic cracking, one using only temperature action,
The other uses the active site of the catalyst.

In a conventional steam cracking unit, a steam thermal cracking unit, the hydrocarbon insert is progressively heated in a tubular furnace, which is a completely endothermic reaction and occurs primarily in the tube section that experiences maximum heat flow. . The temperature of these tubes is determined by the nature of the hydrocarbon being cracked (these hydrocarbons are generally ethane or liquefied petroleum gas or LPG or gasoline, naphtha or in some cases gas oil). Regardless of the nature of the insert, this temperature is always very high, above 700 ° C. However, this temperature is limited to temperatures of up to 850 ° C due to process operating conditions and due to the complexity of furnace operation using additional heating energy.

Conventional fluid bed cracking unit (Fluid Cataly
In the tic cracking or FCC method), a hydrocarbon insert, typically a heavy insert such as gas oil or distillation residue, is contacted with a cracking catalyst suspended and retained in the vapor. After reaching the desired molecular weight range by cracking and the corresponding lowering of the boiling point, the catalyst is separated from the product, stripped, regenerated by combustion of the coke deposited on it, and then cracked again. Contact the insert.

Generally, this catalytic cracking reaction is carried out in the temperature range of 450-550 ° C. The reaction is also carried out so that the cracking unit is in thermal equilibrium without the use of additional heating energy. In other words, the catalyst regenerated by combustion of the coke deposited on the catalyst during the reaction must accommodate the various heat requirements in the reaction section, such as: Preheating of the liquid insert.

-Evaporation of this insert.

The addition of the required amount of heat for the various reactions, which are totally endothermic reactions.

Therefore, the steam cracking method and the catalytic cracking method can further process hydrocarbon inserts having different properties under different reaction conditions.

[Objects and effects of the invention]

It is an object of the present invention to perform a steam thermal cracking reaction of a light hydrocarbon fraction containing saturated light gas or a fraction from gasoline to gas oil in essentially the same reaction zone in an ascending or descending dilute fluid phase. At the same time, another object of the present invention is to provide a method and an apparatus capable of carrying out a catalytic cracking reaction of a heavy hydrocarbon insert having a boiling point range of 500 ° C. or higher.

In fact, as is known, catalytic cracking of heavy hydrocarbons (see Applicant's European Patent 208,609) allows subsequent gas phase reactions so that they are at or above the vaporization temperature of the hydrocarbons. Needs temperature. If the evaporation temperature is much higher than that required for the cracking reaction itself, the temperature of the suspending medium of the catalyst particles and the hydrocarbon after a certain contact time is changed to a fluid with a lower boiling point in this medium, for example Light circulating oil or LCO (Light Cyc
ie Oil) and heavy circulating oil or HCO ((Harvy C
ycle Oil) can be introduced to lower the level suitable for catalytic cracking reaction.

Also, these heavy inserts tend to produce a substantial amount of coke at the reaction conditions due to their content of asphaltene, resin or polyaromatic ring compounds, which in some cases may be associated with the heat balance of the unit. Much higher than the amount needed to satisfy.

The present invention takes advantage of this property that the heavy inserts produce coke, not only providing the catalyst with the energy required for the evaporation of the heavy inserts during combustion of the coke, but also providing additional energy to the catalyst. In addition, in the upstream part of the reaction zone, the conditions necessary to effect mild steam cracking of light hydrocarbons, especially including ethane, propane, butane, light gasoline, naphtha and gas oil are present.

It is therefore an object of the present invention to provide at least one stage of steam cracking at least one light hydrocarbon fraction in the upstream part of an essentially upflow or downflow tubular reaction zone and at least in the downstream part of said reaction zone. Catalytic cracking of a heavy hydrocarbon fraction, ballistic separation of used catalyst particles, regeneration of the catalyst in at least one combustion zone of the coke deposited on these particles, regeneration A step of recycling the catalyst to the feed section of the reaction zone, the vapor cracking process in the presence of fluidized bed catalyst particles, wherein the steam cracking comprises the light hydrocarbons inside the fluidized bed of catalyst particles, By contacting with an amount of steam equal to at least 20% by weight of light hydrocarbons, preferably 30 to 50% by weight. The temperature generated from the contact is 650 to 850 ° C, preferably 700 to 8 ° C.
Within the range of 00 ° C, catalytic cracking of heavy hydrocarbons is carried out by injecting the effluent coming from the weight part of the reaction zone into the catalyst suspension medium, the mixture temperature being initially between 500 and 650 ° C. Within the temperature range of 475 to 550 ° C, by injecting a hydrocarbon fraction that completely evaporates at the exit condition of the reaction zone, immediately above the charge evaporation temperature, and immediately downstream of the injection point of the heavy insert. To provide a method made in.

The light hydrocarbons to be steam cracked can be introduced into the reaction zone by one or more injection lines, depending on their nature. More specifically, according to a particularly preferred embodiment of the process according to the invention, the various hydrocarbon fractions to be injected are introduced sequentially in the order of their boiling points from upstream to downstream of the reaction zone, the lightest fraction being the highest temperature. Introduced into the area. For example, ethane in the most upstream part of the reactor,
That is, the regenerated catalyst is introduced into the hottest injection area,
Gasoline can be introduced immediately downstream. The temperature in this downstream introduction zone is reduced as a result of the contact between the catalyst and ethane, but is still sufficient for the pyrolysis of gasoline. Furthermore, according to the same principle, the naphtha fraction and then the gas oil fraction could be introduced.

In this way, the steam cracking zone is divided into as many zones as the saturated light hydrocarbon fraction to be steam cracked and the reaction severity of these zones is reduced.

In this case, the amount of water vapor injected in the upstream part of the reaction zone is important compared to the usual fluidized bed cracking conditions. However, this amount is much lower than the values used in conventional steam cracking processes. This is because the process in this case does not cause the formation of a certain amount of coke. In practice, the amount of water vapor is 20-60% by weight, preferably 30-50%, based on the amount of hydrocarbons that are steam cracked.
It is included in the range of wt%. As a result, in order to maintain the fluidized bed at the desired temperature for steam cracking, enough steam is injected into the reaction zone to prevent or at least minimize the polymerization of olefins and diolefins. It is necessary to add heat. Such calorimetric conversion is obtained according to the invention by catalytic cracking of heavy hydrocarbon inserts in the downstream portion of the reaction zone.

Due to technical reasons, partly due to the metallurgical resistance of the apparatus, and partly to the problem of catalyst stability at the temperatures necessary to carry out the process of the invention, two separate combustion chambers are provided. An equipped catalyst regenerator can be used to provide the required amount of catalyst particles at a sufficiently high temperature (Applicant's European Patent 18
See No. 4,517).

The first advantage of the process of the invention relates to the fact that the steam cracking reaction in the upstream part of the reactor requires a large amount of heat due to its very high endotherm (5-10 times that of the catalytic cracking reaction). is there. This large amount of heat absorption in the weight portion of the reactor acts as a hot well, resulting in increased catalyst circulation, as in other catalyst cracking cases. As a result, the ratio of the amount of catalyst to the amount of cracked insert (commonly referred to as the C / O ratio) is much higher than in the prior art (see EP 208,609) and, as a result, is cracked. The yield of gasoline and gas oil is significantly improved with respect to the amount of heavy inserts. In particular, this C / O ratio lies in the range 4-12 in the downstream part of the reaction zone.

A second advantage of the present invention is the ability to convert low value light fractions such as ethane or some gasoline fractions to ethylene, propylene, and butenes. Moreover, it is carried out at higher selection conditions than conventional steam cracking. For example, according to a particularly preferred embodiment of the present invention, the reaction effluent fractionator of the cracking unit comprises, as is known per se, the above hydrocarbons and light gases and hydrocarbons of 2, 3 or 4 carbon atoms. It is possible to selectively fractionate. More specifically, separating ethane from other gas effluents,
Recirculating into the hottest part of the reaction zone, optionally combined with fractions coming from other units, i.e. into the zone where the regenerated hot catalyst is introduced, upstream of the introduction zone for gasoline or gas oil. You can let me do it.

In this structure, in the upstream part of the reaction zone,
In two zones of reduced severity, with water vapor at least two fractions, namely a fraction containing mainly ethane but optionally propane and butane, and then a fraction containing light gasoline, then In some cases, mild steam cracking is implemented by injecting naphtha and gas oil.

According to a particularly preferred embodiment of the present invention, the amount of propylene produced can be significantly increased by appropriately recycling the 2-carbon hydrocarbon produced during the reaction.
For this purpose, it is known to use a mixture of ethane and ethylene generated from the fractionation section, which mixture is for example of the type known in the art (European Patents 12,685, 24,971, 21).
5,609 or U.S. Pat. No. 4,605,807) sent to a dimerization or oligomerization reactor of ethylene and after fractionation of the effluent-on the one hand unreacted ethane which is reacted according to the invention. It is circulated to the inlet of the upstream part of the zone-on the other hand, the light gasoline resulting from the oligomerization reaction is optionally circulated with other gasolines into a low severity steam cracking zone to increase the production of propylene and butenes. Can be used.

Another advantage of the present invention is that the hydrogen naturally produced in steam cracking in the upstream part of the reactor is
It is to react under the reaction conditions in the downstream portion of the reactor to increase the yield of high value products.

Thus, steam cracked hydrocarbon fractions usable in the present invention include saturated light gases such as ethane, propane, or butane, or saturated or unsaturated heavy hydrocarbons such as light gasoline, naphtha or gas oil, and even Contains some high boiling but strongly paraffinic fractions such as paraffin or slack wax. These hydrocarbon fractions can be obtained from various refining units such as atmospheric distillation unit, viscosity reduction unit, hydrocracking unit, oil production unit, or olefin oligomerization unit, or be the effluent of the conversion unit itself. You can

The main insert injected downstream of the mild steam cracking zone can be a catalytic cracking unit type insert, but, unlike known methods, heavy inserts can also be used.

Examples of inserts that can be treated according to the invention are vacuum distilled gas oils, heavier hydrocarbon oils, such as optionally topped crude oils, and atmospheric distillation residues or vacuum distillation residues. . These inserts can be subjected to a pretreatment such as hydrotreatment if desired. In particular, these inserts can contain a fraction rich in asphaltenes with a Conradson carbon content of 10% or more. These inserts are used diluted or undiluted with normal light ends,
This light fraction is a hydrocarbon fraction that has already been cracked and circulated, such as cracking gas oil or LCO.
Or it can be HCO. Finally, these inserts can be preheated within the temperature range of 100-400 ° C.

Due to the presence of large amounts of high temperature catalyst coming from the upstream part of the reaction zone, all these high boiling hydrocarbon inserts are easily vaporized by proper spraying into the reaction zone. In this case, the heaviest compounds, especially asphaltene in the insert, undergo a very selective thermal decomposition to form light products which can be catalytically cracked in the downstream reaction zone.

Thus, hydrocarbon injection into the downstream portion of the reaction zone is carried out by a high performance atomizer such as a Venturi type nozzle atomizer, providing a minimum diameter for the drops of 100 microns or less, preferably 50 microns or less. Practically such spray fineness causes the droplets to evaporate almost instantaneously when they come into contact with the hot catalyst stream.

The temperature at which the insert and catalyst particles are mixed is high enough to effect complete evaporation of all components of the insert, but the HC
By injecting another hydrocarbon fraction, such as a liquid fraction of O or LCO, it is independent of the final temperature of the catalytic cracking further downstream. The other liquid fractions mentioned above are injected at a temperature and in an amount that allows the temperature of the other parts of the reaction zone to be adjusted so that catalytic cracking is carried out at optimum conditions. Therefore, the final reaction temperature corresponds to the insert to be cracked, the cracking conditions, and the type of running desired (eg gasoline running: final temperature 500-530 ° C, or gas oil running, final temperature 480-510 ° C). The device comprises means for adjusting the circulating feed so that it is maintained at a specified value. In this way, the temperature of the vaporized cracking insert and catalyst mixture is maintained above the dew point of the insert to match the cracking temperature to the desired selectivity of the cracking effluent.

It is therefore also an object of the present invention to provide a reaction zone in which a petroleum fraction is brought into high temperature contact with catalyst particles in an essentially upflow or downflow annular reactor, and the fraction cracked with said particles. Includes means for ballistic separation, means for stripping catalyst particles, means for regenerating particles by combustion of coke deposited on these particles, and means for circulating the regenerated particles to the feed point of the reactor. In a catalytic fluidized bed converter of petroleum fractions, the apparatus comprises at least one light hydrocarbon fraction, such as saturated light gas, gasoline or gas oil, in the upstream portion of the annular reactor, At least 20% by weight, preferably 30
A means for injecting with an amount of steam equal to ˜50% by weight, so that a mixture with a temperature of 650-850 ° C. is obtained in a dilute fluidized bed, and the device is more efficient in the downstream part of the tubular reactor At least one heavy hydrocarbon insert with a mixture temperature higher than the evaporation temperature of this hydrocarbon.
A first means for atomizing injection under conditions comprised in the range of 500-650 ° C. and an injection area for said heavy hydrocarbon insert for injecting a hydrocarbon fraction which completely evaporates at the exit conditions of the reaction area. And a second atomizing injection located immediately downstream.

This temperature of the converted effluent is achieved by atomizing injection of a quantity of LCO or HCO downstream of the injection area of the heavy insert.
It is kept within the range of 475-550 ℃. This atomization is carried out by injectors of the known type, in which at least 80% of the drops exhibit a diameter of 100 microns or less, as in the case of heavy inserts.

The present invention is not limited to the above description, and can be arbitrarily modified and implemented within the scope of the gist thereof. Therefore, the ratio of the flow rate of the heavy hydrocarbons introduced in the downstream part of the reaction zone to the flow rate of the light hydrocarbons introduced in the upstream part (especially ethane and gasoline) is within a large range, for example between 0.20 and 1.50. It can vary within a range.

Any type of catalyst having catalytic cracking capabilities can be used to carry out the process of the present invention. A particularly desirable type of catalyst is one that has a porous structure and allows the insert molecule to contact the active sites in the pores.
Among this class are especially silicates or aluminosilicates. Zeolites on supports, especially containing various metal oxides, oxide combinations such as silica, alumina, magnesia, titanium oxide, barium oxide and mixtures thereof, and mixtures of said oxides with crosslinked or uncrosslinked clays. Catalysts containing are commercially available. Of course, the catalyst composition can contain one or more compounds that facilitate any process step. In particular, the catalyst may contain compounds that promote the combustion of coke during regeneration.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. This figure illustrates an application of the invention to a fluidized bed conversion assembly comprising an ascending reaction column or "riser" and two reaction chambers, which is particularly suitable for complete regeneration of a catalyst which can be heated to high temperatures.

The essential part of the rising fluidized bed converter shown in this figure is
It is called the reaction tower 1, ie the insert elevator or riser. This riser receives from its bottom the catalyst particles regenerated by line 2, the amount of which is regulated by valve 3. The regenerated catalyst particles are sent to the bottom of the riser by the line 4 and fluidized by the steam or gas diffused by the diffuser 5.

A light saturated gas, in particular consisting of ethane, is introduced into the riser from the diffuser 7 by means of the line 6, supplemented with steam from the line 10. Therefore 750 ℃ in this reaction chamber
Above, preferably above 800 ° C, thermal cracking of the vapor of this light saturated gas occurs. Downstream of this first steam cracking zone, the gasoline or gas oil fraction injected by the diffuser 8 through line 9 is cracked at the lower temperature level, a temperature of 150-750 ° C. Also in this case, steam is added by the line 10 '.

Hydrocarbon inserts heavier than gas oil are introduced into the reactor by injectors via line 12, the amount being such that the temperature of this part of the reaction column 1 is at or above the evaporation temperature of the inserts. . Then, by injecting hydrocarbons such as light diluent (LCO) or heavy diluent (HCO) through line 13 through injector (s) 14, the mixture temperature is adjusted to a value suitable for catalytic cracking, i.e.
It is desirable to set the temperature to 475 ° C to 500 ° C.

The reaction tower 1 opens into the casing 15 at its apex,
The casing has a concentric structure in which the cracked inserts are separated and the spent catalyst particles are stripped. Casing 15
A cyclonic or non-cyclonic ballistic separation system is installed in the inside, and the hydrocarbons flowing out are discharged by the discharge line 16 provided at the top of the casing 15, but the used catalyst particles descend to the bottom of the casing 15. The stripping gas is supplied from the line 17 to the bottom through a plurality of diffusers 18 which are regularly arranged. The particles thus stripped are discharged through a conduit 19 towards the regenerator, on which conduit 19 a regulating valve 20 is provided.

The regenerator illustrated in this figure includes a first zone 21 in which coke deposited on the catalyst particles is burned in the presence of oxygen. That is, the accumulated coke is sent from the line 22 to the diffuser.
It is burned by air injected through the bottom of the regenerator through 23. The combustion gas is separated from the catalyst particles in the cyclone and the combustion gas is discharged by line 25,
The partially regenerated catalyst particles are sent to the second combustion zone 26 by means of a central conduit 27 which is supplied with air by a line 28. Air is also supplied to the bottom of the second section 26 from the line 30 through the diffuser 29. The regenerated catalyst particles are discharged into the side buffer casing 31 and then the conduit 2
Through the bottom of the elevator 1. Second area 26
The combustion gas discharged from the upper part of the is treated in the cyclone 32. The cyclone is external to the combustion chamber, from the bottom of which the catalyst particles are returned by conduit 33 into the second zone 26 and the combustion gases are discharged via line 34.

Further, the reaction effluent leaving stripping section 15 through line 16 is fed into fractionator 35, which
35 separates light or dry gases (especially a mixture of hydrogen, methane, ethane, ethylene, NH ₃ and C ₃ to C ₅ hydrocarbons of H ₂ S) by line 36, these gases then being In a conventional fractionator 37 to separate ethane and ethyl from line 38 and C ₃ to C ₅ hydrocarbons from line 39 as is known.

Separating the gasoline fraction from line 40. Its boiling point interval is from C ₅ to around 160-220 ° C.

-From line 41, a gas oil fraction called LCO, the boiling point interval of which is roughly 160-220 ° C (distillation start) to 320-380 ° C (distillation end).

From line 42, a low-utilization (low viscosity fuel component) heavy dilution fraction called HCO. Its boiling point interval is 320-380 ℃
It is within the range of (distillation start) and 480-500 ℃ (distillation end).

-Finally from line 43 the distillation residue. It contains the heaviest and most difficult to crack products and also contains a considerable amount of catalyst powder. This residue has a boiling point of approximately 400 ° C. or higher (but also contains all distillation residues with a boiling point of 320 to 380 ° C. or higher) and is commonly referred to as a “catalyst slurry”.

According to a particularly preferred embodiment of the invention, the ethane and ethylene leaving line 38 are introduced into the oligomerization reactor 44. Next, the fractionator 45 discharges ethane and unreacted ethylene from the line 46, and the olefinic light gasoline (boiling point 30 to 100 ° C.) is extracted by the line 47. Therefore, the line 46 allows the ethane thus recovered to be circulated to the upstream portion of the reactor by the line 46, and the gasoline recovered as described above can be used as it is, or propylene can be produced. It is circulated through line 9 for maximum cracking and steam cracking.

Finally, a part of the HCO leaving the fractionating section 35 is circulated to the line 13 by means of the line 42 and used to regulate the reaction temperature downstream of the reaction column 1. This temperature adjustment is carried out by means of valve 48, the flow rate of which is adjusted so as to correspond to the temperature measured by a sensor, which is preferably arranged at the outlet of the reactor.

Similarly, valves 49 and 50 regulate the amount of light hydrocarbons introduced into the upstream portion of the reaction zone via lines 9 and 6, respectively, corresponding to the temperature measured in this portion, which temperature is 650-8.
It is kept within the range of 50 ° C. to ensure steam cracking according to the invention at this point.

A gasoline fraction (straight run fraction) and an atmospheric distillation residue of SHENGLI type crude oil as insert A were placed in the same rising fluidized bed unit having two regeneration zones of the type shown in FIG. It was used to perform the following tests. These inserts have the following properties.

Gasoline insert A-Density (15 ° C) 0.675 0.955 Distilled volume%, 50 ° C: 20-70 ° C: 70-100 ° C: 99-Distillation weight% 450 ° C: -20 550 ° C: -45 650 ° C: - 70 - paraffin / naphthenic / aromatic (wt%): 77/17/6 -H ₂ (wt%) 15.4 12.1 -S (wt%) - 1.0 - total N (wt%) - 0.6 -C (wt% ) -8.1-Ni + V (ppm) -40 A commercially available catalyst containing ultrastable zeolite and a substrate suitable for cracking the heaviest hydrocarbon molecules is used. In this test, ethane and gasoline were sequentially introduced upstream of the reaction zone, then insert A and a specific amount of HCO were introduced downstream under the following conditions.

Area upstream of riser: ethane injection-regenerated catalyst temperature (° C): 800-regenerated catalyst temperature (t / h): 720-320 ° C steam flow rate (t / h): 40-ethane flow rate ( t / h): 5-Mixture temperature (° C): 785 Gasoline injection-320 ° C steam flow: 1-150 ° C gasoline flow: 20-Mixture temperature (° C): 725 Downstream of riser: Insert injection -320 ° C steam flow (t / h): 2.5 -380 ° C Insert A flow: 100-Mixture temperature (° C): 575 HCO circulating injection -200 ° C HCO flow: 25 -320 ° C steam Flow rate: 0.5-Temperature of the mixture (° C): 530-Temperature at the end of the reaction (° C): 525 This is analyzed after the effluent of the conversion reaction is collected. Analytical results (total amount of hydrocarbons to be converted, ie ethane,
% By weight with respect to gasoline and atmospheric distillation residues) itself show the advantages of the process of the invention over conventional processes.
The results are as follows.

Weight% H ₂ S + NH ₃ : 0.7 H ₂ : 0.4 C ₁ : 2.8 C ₂ : 3.1 C ₂ (olefin system): 6.8 C ₃ : 1.0 C ₃ (olefin system): 6.1 C ₄ : 2.6 C ₄ (olefin system) : 6.6 fraction (C ₅ -220 ° C.): 39.3 fraction (220-360 ℃): 18.5 fraction (360+) 4.4 coke 7.7

[Brief description of drawings]

The attached drawing is a schematic view of an apparatus for carrying out the fluidized bed hydrocarbon conversion method of the present invention. 1 ... Reaction tower, 7 ... ethane diffuser, 8 ... gasoline diffuser, 10,10 '... steam supply pipe, 11 ... insert nozzle, 14 ... HCO nozzle, 15 ... separator, 21 ...
… First combustion zone, 26 …… Second combustion zone, 35 …… Distillation tower,
44: Oligomerization device, 45: Fractionation tower.

Continuation of the front page (72) Inventor Jean-Claude, Krusel Montivillier, France, Amour, De, La, Peyniere (No house number)

Claims (13)

(57) [Claims] 1. At least one step of steam cracking at least one light hydrocarbon fraction in the upstream part of an essentially upflow or downflow tubular reaction zone and at least one step in the downstream part of said reaction zone. Catalytic cracking a heavy hydrocarbon fraction, ballistically separating spent catalyst particles, regenerating the catalyst in at least one combustion zone of coke deposited on these particles, regenerated catalyst In the presence of fluidized bed catalyst particles, wherein the steam cracking is carried out in the fluidized bed of catalyst particles with the light hydrocarbons and the light hydrocarbons. Carried out by contacting with water vapor in an amount equal to at least 20% by weight of hydrogen, preferably 30 to 50% by weight. The temperature generated from the contact is 650 to 850 ° C, preferably 700 to 800.
In the range of ° C, catalytic cracking of heavy hydrocarbons is carried out by injecting the effluent coming from the upstream part of the reaction zone into the catalyst suspension medium, the mixture temperature being initially above the charge evaporation temperature. of
475-550 by injecting a hydrocarbon fraction which is in the range of 500 to 650 ° C and then immediately downstream of the injection point of the heavy insert, which vaporizes completely at the exit conditions of the reaction zone.
A method characterized by being performed within a temperature range of ℃. 2. Process according to claim 1, characterized in that the light hydrocarbon fraction to be steam cracked comprises saturated light gas, gasoline, naphtha and / or gas oil. 3. The light hydrocarbon is at least 2 from upstream to downstream of the reaction zone according to the order of its boiling points.
Process according to claim 2, characterized in that the lightest fraction is injected into the zone and the lightest fraction is introduced into the zone of highest temperature. 4. The catalytically cracked heavy hydrocarbon insert comprises an insert of the atmospheric distillation or vacuum distillation residue type, at least 20% by weight of the insert having a boiling point of 550 ° C. or higher. Method according to any of claims 1 to 3, characterized. 5. The hydrocarbon fraction injected immediately downstream of the injection point of the heavy insert consists in large part of the HCO or LCO recycle coming from the fractionation of the effluent leaving the reaction zone. Method according to any of claims 1 to 4, characterized in that 6. The hydrocarbon fraction injected downstream of the reaction zone is atomized in drops, at least 80% of these drops being 100%.
A method according to any of claims 1 to 5, characterized in that it has a diameter of less than a micron. 7. The catalyst particles are regenerated by burning coke deposited on the particles in two separate combustion chambers each equipped with a means for discharging exhaust gas. The method described in any one of. 8. A process according to claim 1, wherein the ratio of the amount of catalyst to the amount of cracked insert is in the range 4.0 to 12.0 in the downstream part of the reactor. 9. Ethylene from the fractionation of the reaction effluent is fed into an oligomerization reactor, the effluent of the oligomerization reactor being circulated in the upstream section of the reaction column. Item 9. The method according to any one of Items 1 to 8. 10. A reaction zone in which a petroleum fraction is brought into high temperature contact with catalyst particles in an essentially upflow or downflow annular reactor (1) and said particles and said fraction cracked. Means for ballistic separation, means for stripping catalyst particles (18), means for regenerating particles by combustion of coke deposited on these particles (21, 26), and supply of regenerated particles to the reactor In a catalytic fluidized bed converter for petroleum fractions comprising means (2) for circulating to a location in the upstream portion of the annular reactor of at least one of saturated light gas, gasoline or gas oil. Light hydrocarbon fraction should be at least 20% of this hydrocarbon content.
A means (7,8) for injecting with an amount of steam equal to 30% by weight, preferably 30-50% by weight, which results in a mixture at a temperature of 650-850 ° C. in a dilute fluidized bed, and In the downstream part of the tubular reactor, the device atomizes and injects at least one heavier hydrocarbon insert under conditions where the mixture temperature is above the vaporization temperature of this hydrocarbon insert and is in the range of 500-650 ° C. And a second atomization injection located immediately downstream of the injection zone of the heavy hydrocarbon insert for injecting a hydrocarbon fraction which completely vaporizes at the outlet conditions of the reaction zone with the first means (11) 14) A device characterized by including and. 11. The injection means (11) according to claim 10, characterized in that the heavy hydrocarbon insert is atomized into droplets having a diameter of at least 80% of 100 microns or less. apparatus. 12. In the upstream part of the reaction zone, ethane is successively added,
12. Device according to claim 10 or 11, characterized in that it then comprises means (7, 8) for injecting gasoline. 13. The second injection means (14) is LCO or HCO.
And these injection means (14) are connected to means for measuring the temperature at the outlet of the reaction zone in order to keep the temperature at the outlet substantially constant between 475 ° C and 550 ° C. 13. Device according to any of claims 10 to 12, characterized in that it comprises control means (48).