TW201538708A - Catalytic reforming process - Google Patents

Abstract

The present invention concerns a process for the production of gasoline with an octane number of more than 95, starting from a naphtha cut (1) comprising paraffins and naphthenes, the process comprising the following steps: (a) sending the naphtha cut to a first catalytic reforming unit (2) in order to convert at least a portion of the paraffins and/or naphthenes into aromatic compounds and to produce hydrogen; (b) withdrawing a first effluent (3) and a stream of hydrogen from the first catalytic reforming unit (2); (c) sending the first effluent (3) to a separation unit (5) so as to separate a light hydrocarbon cut (6) containing straight chain paraffins and a heavy hydrocarbon cut (7) containing unconverted paraffins and/or naphthenes; (d) sending the light hydrocarbon cut to an isomerization unit (11) in order to produce an isomerate (12); (e) sending the heavy hydrocarbon cut to a second catalytic reforming unit (8); (f) withdrawing a reformate (10) containing aromatic compounds from the second catalytic reforming unit.

Description

Catalytic recombination

The present invention relates to a process for producing a gasoline fraction having a high octane starting from a naphtha fraction which can be upgraded to a gasoline blend of a refinery.

The conventional purpose of catalytic recombination units is to convert naphthenic compounds (cycloalkanes) and paraffinic hydrocarbon compounds (normal paraffin and isoparaffin) into aromatic hydrocarbon compounds. The main reactions involved are the dehydrogenation of naphthenes, the dehydrocyclization of paraffins to aromatics and, possibly, the isomerization of paraffins and naphthenes. Other reactions known as "side reactions" may occur, such as hydrocracking and hydrogenolysis of paraffins and naphthenes, alkylaromatics which result in the formation of light compounds and lighter aromatic hydrocarbons and coke on the surface of the catalyst. Hydrodealkylation.

The performance to be optimized for gasoline applications is the yield of liquid reconstituted oil and the octane number of the reconstituted oil.

Conventional feeds for catalytic recombination units are rich in paraffin and naphthenic compounds and relatively lack aromatic hydrocarbon compounds. These feeds are typically naphtha obtained from the distillation of crude oil or natural gas condensate treated by catalytic recombination.

In addition to their conventional feeds, other quantities of aromatic hydrocarbons (ie, from catalytic cracking (FCC), from coking, heavy naphtha from hydrocracking or steam cracked gasoline) are also available in the refinery. Feeding. These feeds having varying degrees of aromatic hydrocarbon compounds can be used to supply catalytic recombination units for the production of gasoline or aromatic bases.

The catalytic recombination unit typically comprises four reactors arranged in sequence, the four reactors comprising a fixed or moving bed of recombination catalyst.

When the recombination unit consists of a reactor having a moving catalyst bed, it also contains a continuous catalyst regenerator in which the coke deposited on the catalyst is removed in the form of CO ₂ by slow controlled combustion. This unit (referred to as "continuous regeneration unit") includes a complex device for moving the catalyst, which can thus perform its function instead in the reactor, then undergo regeneration processing and return to the reactors.

The prior art document US 2013/0026066 discloses a method for producing a gasoline base starting from a naphtha fraction. The proposed layout transfers the naphtha feed to a fractionation unit that produces a light naphtha fraction and a heavy naphtha fraction. The light naphtha fraction is subjected to isomerization and the heavy naphtha fraction is again separated into a paraffin fractionation section and a non-paraffin fractionation section. The paraffin fractionation section is treated in an isomerization unit, while the non-paraffin fractionation section is passed to a catalytic recombination unit. The various streams thus produced by the process are then transferred to the refinery's gasoline sum.

Thus, the layout set forth in this document relates to the step of paraffin/cycloalkane separation on a heavy naphtha fraction that is difficult to implement. In addition, the layout illustrates the isomerization step for all paraffin waxes (specifically heavy paraffin waxes containing more than 7 carbon atoms). Isomerized heavy paraffin is extremely difficult to perform and requires operation at elevated temperatures with long residence times.

It is an object of the present invention to provide a flexible method which can produce a directed effluent towards a gasoline base in accordance with the requirements of a refiner, and which optimizes the conversion conditions for it, and which produces a specific processing capacity over prior art More flammable bases with high octane ratings.

To this end, a process for producing gasoline having an octane number of 95 or more, starting from a naphtha fraction comprising paraffin and naphthenic, is proposed, the method comprising the steps of: a) delivering the naphtha fraction To a first catalytic recombination unit, wherein the naphtha fraction is contacted with a recombination catalyst to convert at least a portion of the paraffin and/or naphthenic to an aromatic compound and produce hydrogen; b) extracting from the first catalytic recombination unit An effluent and a hydrogen stream; c) conveying the first effluent to a separation unit for separating a C6 ^- hydrocarbon fraction containing linear paraffin with a C7 ⁺ hydrocarbon fraction containing unconverted paraffin and/or naphthenic or containing a linear chain paraffin C7 ^- hydrocarbon fraction containing unconverted paraffins and / or cycloalkyl of C ₈ ⁺ hydrocarbon fraction separated; D) a C6 ^- hydrocarbon fractions or C7 ^- hydrocarbon fraction is sent to the isomerization unit, in which these linear Paraffin isomerization catalyst in contact with the other in order to be converted into linear paraffin and a branched paraffin oil was isomerized gasoline delivered to the sum; E) a C7 ⁺ hydrocarbon fraction or C ₈ ⁺ hydrocarbon fraction transferred to the second Catalytic recombination unit to convert unconverted paraffin and/or naphthenic Chemical aromatic compound; F) from the second catalytic reforming unit extracts a stream of hydrogen and an aromatic compound containing a recombinant of an oil.

The method of the present invention can be used to produce not only a gasoline fraction (isomerized oil) rich in linear paraffin wax having a high octane rating, but also a base which can serve as a gasoline aggregate and which may act as an aromatic error. A gasoline fraction (recombinant oil) rich in aromatic hydrocarbon compounds based on the base of the composite unit. Therefore, depending on the requirements of the refiner, the gasoline fraction (recombinant oil) rich in aromatic hydrocarbons is oriented towards the total gasoline, when it is needed, or both the gasoline base and the aromatic hydrocarbon base used in petrochemicals. When necessary, it is directed to the gasoline mixture and to the aromatic complex (in any ratio).

Since the first and second steps are separated, and catalytic reforming of light C6 ^- or C7 ^- fraction of the heavy C7 ⁺ or C ₈ ⁺ fraction of the intermediate steps, thus the method of the invention is also the ability of an aromatic hydrocarbon and the product yield rates Optimized. Separation step may be used to recover transformed into aromatic compounds containing hard but relatively easily isomerized to branched chain paraffins of light of the light branched paraffins C6 ^- or C7 ^- fraction. Thus, a second step of catalytic reforming or C7 ⁺ C ₈ ⁺ hydrocarbon fraction operable to perform the conversion may be clear during a first step of catalytic reforming of unconverted paraffinic and / or naphthenic and to avoid the unintended side reactions (such as For example, hydrocracking and hydrogenolysis of paraffin and naphthenes are hydrodealkylates of alkyl aromatic hydrocarbons which are responsible for the formation of coke on the surface of the recombination catalyst. Furthermore, by means of the intermediate separation, it is not necessary to unnecessarily increase the ability to produce units, since heavy repeating resistance to strong light paraffin compounds is separated, and in particular only heavy paraffins which are relatively easy to convert into aromatic compounds and/or The naphthenic compound is treated.

In a preferred embodiment, the first recombination step is operated under conditions conducive to dehydrogenation of a naphthenic compound which is more readily dehydrogenated and converted to aromatic than paraffin which must undergo dehydrocyclization. Compound. This second recombination step is then carried out under conditions more severe than in the first recombination step to promote the heavy paraffin dehydrocyclization reaction.

In one embodiment, all of the reconstituted oil is delivered to the gasoline sum when promoting the production of the gasoline base.

According to another embodiment in which an aromatic base for petrochemicals and gasoline will be produced, one portion of the reconstituted oil is transferred to the aromatic complex unit and another portion of the reconstituted oil is transferred to the gasoline confluence.

In a particular embodiment, the naphtha fraction is pretreated in a hydrotreating unit prior to step a). As an example, the hydrotreating step is selected from the steps of hydrodemetallization, hydrodesulfurization, hydrodenitrogenation and/or hydrogenation of olefins and dienes.

According to a preferred embodiment, prior to step a), the naphtha fraction is passed to a separation unit designed to separate the C4 ^- hydrocarbon fraction from the C5 ⁺ hydrocarbon fraction and the C5 ⁺ fraction is passed to step a).

In the presence of hydrogen, the first catalytic recombination step a) and the second catalytic recombination step e) are carried out under the following conditions: ‧ average reactor inlet temperature in the range of 420 ° C to 600 ° C; Pressure in the range of MPa to 1 MPa; ‧ H ₂ /feed molar ratio in the range of 0.2 mol/mol to 8 mol/mol; ‧ hourly weight in the range of 0.5 h ^-1 to 8 h ^-1 The space velocity is expressed as the ratio of the mass flow rate of the feed to the mass of the catalyst.

Preferably, the first catalytic recombination step a) is carried out under the following conditions: ‧ average reactor inlet temperature in the range of 420 ° C to 500 ° C; ‧ pressure in the range of 0.3 MPa to 1 MPa; H ₂ /feed molar ratio in the range of /mol to 8 mol/mol; ‧ hourly weight space velocity in the range of 2.5 h ^-1 to 8 h ^-1 expressed as mass flow rate and contact of the feed The ratio of the quality of the media.

Preferably, the second catalytic recombination step e) is carried out under the following conditions: ‧ average reactor inlet temperature in the range of 500 ° C to 600 ° C; ‧ pressure in the range of 0.3 MPa to 1 MPa; H ₂ /feed molar ratio in the range of /mol to 8 mol/mol; ‧ hourly weight space velocity in the range of 0.5 h ^-1 to 2.5 h ^-1 expressed as the mass flow rate of the feed and The ratio of the mass of the catalyst.

According to the present invention, the naphtha fraction is obtained from one or more of the following units: atmospheric distillation, FCC, coking, steam cracking, hydrocracking, and natural gas condensate fractionation.

Preferably, the catalytic recombination catalyst employed in steps a) and e) comprises a support and a metal (for example, platinum). Highly preferably, the catalytic recombination catalyst is promoted by one of the following elements: Re, Sn, In, P, Ge, Ga, Bi, B, Ir or rare earth.

In a particular embodiment, the recombination catalyst comprises an alumina support, platinum, and optionally one or more promoter elements as set forth above. Preferably, the promoter element is tin.

According to a preferred embodiment, the catalytic recombination catalyst of step a) has a chlorine content of less than 0.1% by weight, preferably less than 0.05% by weight, relative to the total catalyst weight.

Preferably, the catalytic recombination catalyst of step e) has a range of from 0.8% by weight to 1.5% by weight, preferably from 0.8% by weight to 1.2% by weight, and more preferably, relative to the total catalyst weight. The chlorine content in the range of 0.9% by weight to 1.1% by weight.

According to the present invention, the first catalytic recombination unit and the second catalytic recombination unit may use a fixed bed reactor in a "semi-regeneration" mode or a moving bed reactor in a "continuous regeneration" mode. For fixed bed systems, this (for example) includes at least two anti-parallel operations A reactor in which a first reactor is used to regenerate the catalyst and a second reactor is used in a recombination reaction.

In accordance with a preferred embodiment of the present invention, the recombination units function in a "continuous regeneration" mode (continuous catalyst regeneration (CCR)). Units of this type are characterized by continuous in situ regeneration of the portion of the catalyst in the dedicated regenerator and continuous addition of the regenerated catalyst to the reactors performing the conversion reaction.

Thus, this type of "continuous regeneration" recombination reactor includes at least one reactor and a regenerator. Preferably, the recombination unit comprises two reactors and a catalyst regenerator arranged to perform the conversion of the paraffin and naphthenic compounds into aromatic compounds.

According to a preferred embodiment, when the catalyst is the same in the two recombination units, the first recombination unit is comprised of at least one conversion reactor and the second recombination unit comprises at least one conversion reactor and a regenerator, Wherein the first reactor moving toward the first catalytic recombination unit is moved by the regeneration catalyst. This embodiment is advantageous because it means that the mutual regenerator can be used to regenerate the catalyst used in the first recombination unit and the second recombination unit.

In the case where different catalysts are used in each of the first recombination unit and the second recombination unit, the at least one conversion reactor and one regenerator are constructed.

1‧‧‧ Naphtha feed

2‧‧‧First catalytic recombination unit/first recombination unit

3‧‧‧ effluent/first effluent

4‧‧‧ Hydrogen flow

5‧‧‧Distillation separation unit/separation unit

6‧‧‧ fraction / C6 ^- hydrocarbon fraction / C7 ^- hydrocarbon fraction / light hydrocarbon fraction

7‧‧‧ fraction/heavy hydrocarbon fraction/C7 ⁺ hydrocarbon fraction / C ₈ ⁺ hydrocarbon fraction

8‧‧‧Second catalytic recombination unit

9‧‧‧ Hydrogen flow

10‧‧‧Reorganized oil/gasoline fraction

11‧‧‧isomerization unit

12‧‧‧Line/gasoline fraction

14‧‧‧Aromatic complex unit

15‧‧‧Hydrogenation unit

16‧‧‧Distillation point separation unit/separation unit/line

17‧‧‧ gasoline total

Figure 1 shows the layout of the method of the invention.

Other features and advantages of the present invention will be apparent from the following description, taken in conjunction with the accompanying drawings in FIG.

For a better understanding of the text, the term "naphtha" will be used hereinafter to denote an oil fraction having any chemical composition, preferably having a distillation range in the range of 50 °C to 250 °C. Any assignment of the chemical family can be used, denoted PONA (P stands for paraffin, O stands for olefin, N stands for naphthenic and A stands for aromatic hydrocarbon).

The term "gasoline" is used in a distillation range having a distillation range similar to naphtha and An oil fraction having an octane number of 95 or more (preferably 98 or more).

The term "aromatic group" is used in a broad sense to encompass xylene (p-xylene, meta-xylene, o-xylene), ethylbenzene, toluene and benzene, and possibly such as monomeric styrene, cumene or linear Heavier aromatic hydrocarbons of alkylbenzenes.

The term "recombinant oil" is used for gasoline fractions having a high octane number produced by catalytic recombination.

Treated hydrocarbon feed

In the remainder of the text, the term "naphtha" (alone or mixed with other naphtha) is used to indicate a feed that can be treated by the process of the invention. This feed is rich in paraffin and naphthenic compounds and relatively lacking hydrocarbon fractions of aromatic hydrocarbon compounds. The naphtha feed, for example, is obtained from atmospheric distillation or natural gas condensate of crude oil. The process of the invention is also applicable to heavy naphtha produced by heavy naphtha catalytic cracking (FCC), coking, hydrocracking or steam cracking of gasoline. Such feeds having different levels of aromatic compounds can be used to supply catalytic recombination units for the production of gasoline or aromatic bases.

Figure 1 shows the layout of the method of the invention. The naphtha feed 1 described above is passed to a first catalytic recombination unit 2 comprising at least one of a catalytic recombination catalyst bed equipped, for example, as a fixed bed or as a moving bed reactor. The first recombination unit operates under operating conditions and in the presence of a catalyst that is optimized to convert the naphthenic compound (cycloalkane) and/or paraffin compound to an aromatic hydrocarbon compound. To limit the formation of coke on the recombination catalyst, a recombination step is performed in the presence of hydrogen.

The catalyst used in this first recombination unit 2 comprises a support and an active metal phase, for example platinum. Preferably, the metal (specifically, platinum) is associated with other elements (accelerators) selected from the group consisting of Re, Sn, In, P, Ge, Ga, Bi, B, Ir, and rare earth or such Any combination of elements. The support is preferably alumina.

The first catalytic recombination unit operates within the following operating conditions: ‧ average reactor inlet temperature in the range of 420 ° C to 600 ° C; ‧ pressure in the range of 0.3 MPa to 1 MPa; ‧ at 0.2 mol/mol to H ₂ /feed molar ratio in the range of 8 mol/mol; ‧ hourly weight space velocity in the range of 0.5 h ^-1 to 8 h ^-1 expressed as the mass flow rate of the feed and the mass of the catalyst The ratio.

In a preferred embodiment, the first catalytic recombination unit is operated under conditions that promote the dehydrogenation of the naphthenic acid present in the naphtha feed. The dehydrocyclization reaction of paraffin to aromatic hydrocarbons is slower than the dehydrogenation of naphthenes, and thus the paraffin wax is hardly converted in this first recombination step. Therefore, the first recombination step is preferably carried out under the following conditions: ‧ average reactor inlet temperature in the range of 420 ° C to 500 ° C; ‧ pressure in the range of 0.3 MPa to 1 MPa; ‧ at 0.2 mol/mol H ₂ /feed molar ratio in the range of 8 mol/mol; ‧ hourly weight space velocity in the range of 2.5 h ^-1 to 8 h ^-1 expressed as the mass flow rate of the feed and the catalyst The ratio of quality.

In the preferred embodiment, a recombination catalyst having an alumina support and having a chlorine content of less than 0.1% by weight, preferably less than 0.05% by weight, relative to the weight of the catalyst is preferably used. According to a highly preferred embodiment, the catalyst for the first recombination step has a platinum/tin type on alumina having a chlorine content of less than 0.1% by weight, preferably less than 0.05% by weight, relative to the weight of the catalyst.

The first catalytic recombination unit 2 produces an effluent 3 containing an aromatic hydrocarbon compound (specifically, obtained from conversion of a naphthenic and/or paraffin (preferably naphthenic)) and an unconverted non-aromatic compound, and a hydrogen stream. 4. For example, the hydrogen stream 4 is passed to a hydrotreating unit in a refinery or to a second catalytic recombination unit.

The effluent 3 is passed to a fractionation point separation unit 16, for example, a fractionation column. Separation unit 16 is designed to perform two fractions effluent is separated into three, i.e., include those containing 6 or less carbon atoms of a hydrocarbon fraction 6 (represented as C6 ^- fraction of) the hydrocarbon containing 7 or more and comprises carbon atoms Fraction 7 (denoted as a C7 ⁺ fraction), or another line of choice, including a fraction 6 of a hydrocarbon containing 7 or fewer carbon atoms (denoted as a C7 ^- fraction) and including a hydrocarbon having 8 or more carbon atoms Fraction 7 (expressed as a fraction of C ₈ ⁺ ). Amylose-rich light paraffin C6 ^- or C7 ^- hydrocarbon fraction is then processed in the isomerization unit 11, from the isomerization unit to produce a high octane number of the gasoline fraction having a (isomer oil), having the digoxin The gasoline fraction of the alkane value is transferred via line 12 to the gasoline sum. The isomerization unit can be used to convert a normal paraffin (linear paraffin) having a low octane number to an isoparaffin (branched paraffin) having a higher octane number. Since the isomerization reaction is slightly exothermic, the space velocity per hour in the range of 0.2 MPa to 0.8 MPa and in the range of 1 h ^-1 to 3 h ^-1 (HSV = volumetric flow rate of the feed) Under (m ³ /h) / catalyst volume (m ³ )), a low temperature in the range of 110 ° C to 250 ° C is used. The method of the present invention is intended to be increased by means of a light-C6 recombination reaction consumes less energy than the isomerization reaction ^- or C7 ^- octane number of a hydrocarbon fraction. In fact, the light paraffin is difficult to convert into aromatic compounds, and therefore this conversion requires high temperatures, which are then accompanied by undesired reactions of hydrodealkylation and polycondensation, which is the formation of coke on the catalyst. the reason.

Indicated in Figure 1, containing the heavy C7 ⁺ or C unconverted paraffins and possibly the naphthenic ₈ ⁺ hydrocarbon fraction transferred to the second catalytic reforming unit 8, generating hydrogen gas stream from the second catalytic reforming unit 89 and having a high An octane number of recombinant oil 10. This second catalytic recombination step is intended to convert an unconverted non-aromatic hydrocarbon compound (paraffin and/or naphthenic) to an aromatic hydrocarbon compound.

To limit the formation of coke on the recombination catalyst, a recombination step is performed in the presence of hydrogen.

The operating conditions used in the second catalytic recombination step are as follows: ‧ average reactor inlet temperature in the range of 420 ° C to 600 ° C; ‧ pressure in the range of 0.3 MPa to 1 MPa; ‧ from 0.2 mol / mol to 8 mol / H ₂ /feed molar ratio in the range of mol; ‧ hourly weight space velocity in the range of 0.5 h ^-1 to 8 h ^-1 expressed as the ratio of the mass flow rate of the feed to the mass of the catalyst .

It is assumed that due to the fractionation step, the light C7 ^- fraction light paraffin is not transferred to the second catalytic recombination unit, and this second catalytic recombination step may be operated under more severe conditions to convert the paraffin wax into an aromatic compound. Therefore, it is preferred to operate the second recombination step at a higher temperature and/or longer residence time than in the first recombination step, ie: ‧ average reactor inlet temperature in the range of 500 ° C to 600 ° C ; ‧ pressure in the range of 0.3 MPa to 1 MPa; ‧ H ₂ /feed molar ratio in the range of 0.2 mol / mol to 8 mol / mol; ‧ in the range of 0.5 h ^-1 to 2.5 h ^-1 The hourly weight space velocity is expressed as the ratio of the mass flow rate of the feed to the mass of the catalyst.

The recombination catalyst used in the second recombination step can be the same as the recombination catalyst used in the first recombination step. Preferably, a catalyst comprising an alumina support and an active metal phase (for example, platinum) is used. Preferably, the metal (specifically, platinum) is associated with one or more elements (accelerators) selected from the group consisting of Re, Sn, In, P, Ge, Ga, Bi, B, Ir, and rare earths. Or any combination of these elements. Preferably, the catalyst of the second recombination step has a range of from 0.8% by weight to 1.5% by weight, preferably from 0.8% by weight to 1.2% by weight, based on the weight of the catalyst, and more preferably The chlorine content in the range of 0.9% by weight to 1.1% by weight. In a preferred embodiment, the catalyst of the second recombination step comprises an alumina support, platinum and tin and has a chlorine content in the range of from 0.8% by weight to 1.5% by weight relative to the weight of the catalyst, preferably The chlorine content in the range of 0.8% by weight to 1.2% by weight and more preferably in the range of 0.9% by weight to 1.1% by weight.

In a preferred embodiment, in the first recombination unit, a platinum/tin type catalyst having an activity on the dehydrogenation of naphthenes is used, wherein the chlorine content is less than 0.1% by weight based on the weight of the catalyst, Preferably less than 0.05% by weight, and in the second recombination unit, a platinum/tin type catalyst on alumina having high paraffin dehydrocyclization activity, wherein the chlorine content is 0.8% by weight relative to the catalyst weight It is in the range of 1.5% by weight, preferably in the range of 0.8% by weight to 1.2% by weight, and more preferably in the range of 0.9% by weight to 1.1% by weight.

As indicated in Figure 1, the reconstituted oil 10 having a high octane number obtained from the second catalytic recombination unit 8 is all transferred via line 16 to the gasoline sum. Alternatively, one portion of the reconstituted oil is transferred to the gasoline sum and the other portion is passed to the aromatic complex.

"Aromatic complex" means various fractionation units (whether by adsorption, distillation, extractive distillation, liquid-liquid extraction or crystallization), and/or conversion units (regardless of the reconfiguration of aromatic hydrocarbons, such as aromatic hydrocarbons. The method of disproportionation or disproportionation, selective or otherwise aromatic hydrocarbon dealkylation or alkylation unit, or a combination of units with or without isomerization of ethylbenzene dealkylated xylene. The product from the aromatic complex is mainly a petrochemical intermediate (such as benzene, p-xylene, o-xylene, m-xylene, xylene fraction, ethylbenzene, monomeric styrene, cumene or linear alkane). Base benzene) or a component used to form a gasoline base such as toluene or a heavy aromatics fraction.

As indicated in Figure 1, the naphtha feed 1 is treated in the hydrotreating unit 15 to pass the sulfur, nitrogen and/or olefins, as appropriate, prior to delivery to the first catalytic recombination step. Specification for the content of the diene compound.

According to an alternative embodiment (not shown), the naphtha fraction is passed to a separation unit (for example, a distillation column) that is structurally designed to separate the C4 ^- hydrocarbon fraction from the C5 ⁺ hydrocarbon fraction, and the C5 ⁺ fraction is passed to The first step a) is used for catalytic recombination according to the invention.

Instance

The following example compares two method layouts: a layout according to the invention (according to Figure 1) and a layout not according to the invention (where no fractionation point separation unit is present).

In both cases, the feeds considered have the following composition:

In a process other than the present invention, the naphtha feed is passed to a catalytic recombination unit consisting of four reactors arranged in sequence, and a hydrogen stream and a reconstituted oil having a high octane number are produced from the catalytic recombination unit. The composition of the effluent obtained from the outlet of the fourth reactor is set forth in Table 1 below.

In an example according to the invention, the naphtha feed is passed to a first catalytic recombination unit 2 consisting of two reactors. Since the first reaction zone effluent 2 of the future transmission 3 to a distillation separation unit 5, the distillation unit 5 generates light separating C7 ^- C ₈ ⁺ fraction and heavy fraction. The light C7 ^- fraction is sent to the isomerization unit 11, and a gasoline fraction 12 (isomerized oil) having a high octane number is produced from the isomerization unit. The C ₈ ⁺ heavy fraction transmitted by the second catalytic reforming unit to the two reactors constituted of 8, and a hydrogen stream having a high octane number of the gasoline fraction 10 (recombinant oil) from the catalytic reforming unit to generate a second. This gasoline fraction was mixed with an isomerized oil, and the mixed composition is given in Table 1 below.

In both cases, the catalytic recombination unit operates under the same conditions:

‧ Average reactor inlet temperature = 520 ° C

‧ hourly weight space velocity: 2h ^-1 (It should be noted that for method A of the present invention, the hourly weight space velocity of the second recombination unit is recalculated, which is not processed at the same flow rate to maintain case A and case B The amount of catalyst (not according to the invention) is constant)

‧ Relative pressure = 0.5MPa

‧H ₂ /feed molar ratio=2

The catalyst used in the examples was a platinum/tin catalyst on alumina alumina.

Isomerization of the light C7 ^- fraction is carried out under the following conditions and in the presence of platinum isomerization catalyst and hydrogen:

‧ Average reactor inlet temperature = 120 ° C

‧ hourly space speed: 1.2h ^-1

‧ Relative pressure = 0.30MPa

‧H ₂ /feed molar ratio=0.2

Table 1 below compares the yield of research octane number (RON), liquid reconstituted oil (C5 ⁺ ), and the coke content of the catalyst of the fourth recombination reactor when operating the layout of the present invention and the layout according to the present invention. :

The layout in which the present invention is implemented means that there is a 2.4% gain in C5 ⁺ yield compared to the layout not according to the present invention.

A reduction of 1% by weight of coke on the catalyst for the fourth reactor was also observed for the layout of the present invention.

The fact that the effluent obtained from the first catalyst recombination unit is treated by fractional distillation means that the conditions for the conversion of each fraction may be applicable. Since light paraffin is extremely difficult to reconstitute, the recombination step requires vigorous operating conditions that can result in severe cleavage and thus result in the formation of light compounds (C1 to C4). In the arrangement of the invention, the C7 ^- light paraffin wax is advantageously delivered to the isomerization step, wherein the cleavage is limited, due to the moderate temperature regulation, which explains why the yield of the light compound has been reduced and C5 ⁺ The yield has increased.

The layout of the present invention can also be used to reduce the cost of conventional catalytic recombination facilities because the isomerization unit requires lower investment and lower energy consumption to operate.

1‧‧‧ Naphtha feed

2‧‧‧First catalytic recombination unit/first recombination unit

3‧‧‧ effluent/first effluent

4‧‧‧ Hydrogen flow

5‧‧‧Distillation separation unit/separation unit

6‧‧‧ fraction / C6 ^- hydrocarbon fraction / C7 ^- hydrocarbon fraction / light hydrocarbon fraction

7‧‧‧ fraction/heavy hydrocarbon fraction/C7 ⁺ hydrocarbon fraction / C ₈ ⁺ hydrocarbon fraction

8‧‧‧Second catalytic recombination unit

9‧‧‧ Hydrogen flow

10‧‧‧Reorganized oil/gasoline fraction

11‧‧‧isomerization unit

12‧‧‧Line/gasoline fraction

14‧‧‧Aromatic complex unit

15‧‧‧Hydrogenation unit

16‧‧‧Distillation point separation unit/separation unit/line

17‧‧‧ gasoline total

Claims (13)

A method for producing gasoline having an octane number of 95 or more starting from a naphtha fraction (1) comprising paraffin and naphthenic, the method comprising the steps of: a) delivering the naphtha fraction to the first Catalyzing the recombination unit (2), wherein the naphtha fraction is contacted with a recombination catalyst to convert at least a portion of the paraffin and/or naphthenic to an aromatic compound and produce hydrogen; b) from the first catalytic recombination unit (2) extracting the first effluent (3) and the hydrogen stream (4); c) transferring the first effluent (3) to the separation unit (5) to convert the C6 ^- hydrocarbon fraction containing linear paraffin (6) containing untransformed paraffins and / or cycloalkyl of C7 ⁺ hydrocarbon fraction (7) or a straight-chain paraffin C7 ^- hydrocarbon fraction (6) containing unconverted paraffins and / or cycloalkyl of C ₈ ⁺ hydrocarbon fraction ( 7) separating; d) transferring the C6 ^- hydrocarbon fraction or the C7 ^- hydrocarbon fraction to the isomerization unit (11), wherein the linear paraffin is contacted with an isomerization catalyst to convert the linear paraffin branched paraffins and to produce an aggregate transmit to the gasoline (17) of the isomerized oil (12); e) the C7 ⁺ hydrocarbon fraction or the C ₈ ⁺ hydrocarbon fraction transferred to the second catalytic reforming unit (8) To convert the unconverted paraffin and/or naphthenic to an aromatic compound; f) extracting an aromatic oil-containing recombinant oil (10) from the second catalytic recombination unit (8); g) the recombinant oil ( 10) all transferred to the gasoline sum (17) or a portion of the reconstituted oil (10) to the aromatic complex unit (14) and the other portion of the reconstituted oil (10) to the gasoline sum (17). The method of claim 1, wherein the naphtha fraction is pretreated in the hydrotreating unit (15) prior to step a). The method of claim 1 or claim 2, wherein the naphtha fraction is transferred to a separation unit structured to separate the C4 ^- fraction from the C5 ⁺ fraction, and the C5 ⁺ fraction is passed to step a). The method of any one of the preceding claims, wherein the first catalytic recombination step a) and the second catalytic recombination step e) are performed under the following conditions: an average reactor inlet temperature in the range of 420 ° C to 600 ° C a pressure in the range of 0.3 MPa to 1 MPa; a H ₂ /feed molar ratio in the range of 0.2 mol/mol to 8 mol/mol; an hourly range in the range of 0.5 h ^-1 to 8 h ^-1 The weight space velocity is expressed as the ratio of the mass flow rate of the feed to the mass of the catalyst. The method of any one of the preceding claims, wherein the first catalytic recombination step a) is performed under the following conditions: an average reactor inlet temperature in the range of 420 ° C to 500 ° C; in the range of 0.3 MPa to 1 MPa Pressure; H ₂ /feed molar ratio in the range of 0.2 mol/mol to 8 mol/mol; hourly weight space velocity in the range of 2.5 h ^-1 to 8 h ^-1 expressed as the feed The ratio of the mass flow rate to the mass of the catalyst. The method of any one of the preceding claims, wherein the second catalytic recombination step e) is performed under the following conditions: an average reactor inlet temperature in the range of from 500 ° C to 600 ° C; in the range of from 0.3 MPa to 1 MPa The pressure; the H ₂ /feed molar ratio in the range of 0.2 mol/mol to 8 mol/mol; the hourly weight space velocity in the range of 0.5 h ^-1 to 2.5 h ^-1 , expressed as the The ratio of the mass flow rate to the mass of the catalyst. The method of any of the preceding claims, wherein the naphtha fraction is obtained from one or more of the following units: atmospheric distillation, FCC, coking, steam cracking, hydrocracking, and natural gas condensate fractionation. The method of any of the preceding claims, wherein the use in step a) and step e) The catalytic recombination catalyst comprises an alumina support and platinum. The method of claim 8, wherein the recombination catalyst is promoted by one of the following elements: Re, Sn, In, P, Ge, Ga, Bi, B, Ir or rare earth. The method of claim 8 or claim 9, wherein the catalytic recombination catalyst of step a) has a chlorine content of less than 0.1% by weight, preferably less than 0.05% by weight, relative to the total catalyst weight. The method of any one of claims 8 to 10, wherein the catalytic recombination catalyst of step e) has a range of from 0.8% by weight to 1.5% by weight, preferably 0.8% by weight relative to the total catalyst weight The chlorine content in the range of % to 1.2% by weight and more preferably in the range of 0.9% by weight to 1.1% by weight. The method of any of the preceding claims, wherein the first catalytic recombination unit and the second catalytic recombination unit employ the same catalyst and operate according to a continuous regeneration mode, and wherein the first catalytic recombination unit comprises at least one reactor and The second catalytic recombination unit includes at least one reactor and a catalyst regenerator, wherein the regenerated catalyst moves in the reactor of the first catalytic recombination unit. The method of any one of claims 1 to 11, wherein the first catalytic recombination unit and the second catalytic recombination unit employ different catalysts and operate according to a continuous regeneration mode, and wherein the first catalytic recombination unit comprises at least one reaction And a catalyst regenerator and the second catalytic recombination unit comprises at least one reactor and a catalyst regenerator.