PT1447437E - Process to prepare naphthenic hydrocarbons-rich hydrocarbon streams - Google Patents

Description

DESCRIPTION OF THE DRAWING PROCEDURE OF RICH HYDROCARBONATED FLUIDS IN NAFTÉNIC HYDROCARBONETS " The invention relates to a process for the preparation of a hydrocarbon fluid rich in naphthenic hydrocarbons. More particularly, the invention relates to a process for the preparation of non-toxic, non-polluting and odorless hydrocarbon solvents.

In the description, examples and claims which follow, all said distillation ranges are determined according to ASTM D-86.

STATE OF THE TECHNIQUE

Numerous organic solvents of petroleum origin are known today. They are commonly used in cleaning, extraction or dilution applications (for paint and printing inks and printing, for example).

These types of solvents are obtained by direct distillation of petroleum fractions. Solvents should be able to dissolve organic products. They must therefore have a good solvent power vis-à-vis these products. The aniline point reflects the solvent power of a product. It is usually measured in ° C by the method ISO 2977. The lower the aniline point, the more the compound has a good solvent power. However, the aromatic hydrocarbons have a low aniline point and are therefore very good solvents. For example, the xylene has an aniline point of 12 ° C, the toluene has an aniline point of 9 ° C. But aromatic hydrocarbons have the great disadvantage of being very toxic.

The solvents obtained by distillation of crude oil generally contain a high content of aromatic hydrocarbons, which poses the problem of their high toxicity.

For example, petroleum fractions having a distillation range of 230 ° C to 300 ° C, used as solvents for printing ink, may have aromatic content of 20 to 30% by weight.

Moreover, because of their high boiling point, these heavy aromatic compounds are difficult to dry. In particular, in printed ink they tend to evaporate very slowly, so that they remain for a long time in the inks, which can emit toxic vapors and unpleasant smells during use.

Depending on the applications of these solvents, it has sometimes even been proposed to further increase their solvent power to add other aromatic compounds, such as benzene, toluene or xylene: these compounds being particularly hazardous to the body, its content in the solvents must therefore be controlled. 2 The need to manufacture solvents which are less harmful to health means reducing their content of aromatic compounds. It is therefore necessary to replace them with other less toxic compounds.

In order to limit the content of benzene compounds in the solvents, it was proposed to incorporate in these latter non-toxic paraffins. But in this case, other problems arise, such as the reduction of the solvent power or the solidification of the products at low temperature (5-7 ° C). Substitution of the aromatic compounds in the solvents assumes that they are replaced by other compounds, which are not only less toxic, but which also retain a weak aniline point to maintain a good solvent power. Naphthenic hydrocarbons have emerged as a good alternative to aromatic compounds because of their good solvent power and low toxicity.

In order to solve the toxicity and pollution problems induced by the manufacture of the solvents described above, and without significant loss of solvent power, U.S. Patent No. 3,996,304 discloses a process for the manufacture of non-toxic, non-polluting hydrocarbon solvents. Thus, it is a question of obtaining cycloparaffin hydrocarbons by catalytic hydrogenation of aromatic hydrocarbons.

More particularly, the process consists in selecting petroleum fractions rich in certain aromatic compounds, such as benzene, toluene, xylene or naphthalene, subjecting them to a distillation to obtain concentrates of these different pure aromatic products and, finally, hydrogenating these 3 concentrates to obtain the corresponding cycloparaffins.

For example, this patent describes a process for the manufacture of cyclohexane comprising the steps of: (a) distilling a benzene-rich petroleum fraction to obtain a benzene-containing main fraction, (b) extracting the major fraction containing benzene, to remove the benzene from the paraffinic and naphthenic compounds contained in said main fraction, (c) recovery of the benzene enriched solvent, (d) separation of the solvent, on the one hand, and benzene, on the other hand, by distillation, e) recovering benzene with a purity of at least 99%, (f) hydrogenating the benzene on a non-acid catalyst containing platinum and / or palladium, tin, rhodium and an alkali metal.

This process, involving numerous steps, has the drawback of being complicated and costly. It requires significant investments in the refineries, where it is necessary to provide specific equipment for the manufacture, extraction of the intermediate aromatic concentrate and its hydrogenation.

It thus appears that the state of the art suggests only unsatisfactory processes given the current limitations, both in terms of health and the environment, and in economic terms for refineries. None of the existing processes allows simple and economical production of non-toxic, non-polluting hydrocarbon solvents. It is known to valorize hydrocarbon charges by converting them into hydrocarbon products rich in naphthenic hydrocarbons and having a low content of aromatic compounds.

Thus, U.S. Patent No. 4,875,992 generally discloses a process for converting a hydrocarbonaceous charge rich in polycyclic aromatic compounds with condensed rings into high density jet aircraft fuel. This process comprises a desulphurization / deaeration step by hydrotreatment, which is followed by a hydrogenation step leading to the partial saturation of the aromatic compounds from the initial charge.

Similarly, U.S. Pat. No. 6,210,561 generally describes a process in which a hydrocarbon filler having a boiling range greater than 100 ° C is converted into a product rich in naphthenic hydrocarbons having a low aromatic content because of its subsequent use , produced during steam cracking. This process essentially comprises four treatment steps which are: a) a hydrotreating step to eliminate the sulfated and nitrogenous compounds, b) a step of saturation of the double bonds by controlled hydrogenation, c) a steam cracking step of the desulfurized product , de-hydrogenated and hydrogenated, in order to obtain a product consisting of hydrogen, C1-4 hydrocarbons, naphtha, steam cracking gas and steam cracking tar, and d) a step of fractionating and recovering the different products.

DESCRIPTION OF THE INVENTION The present invention is specifically aimed at solving the disadvantages of prior art processes. These disadvantages are, on the one hand, the toxicity and the pollutant nature of the organic solvents from petroleum refining used up to the present, and on the other hand, the complexity and the need for major investments required to carry out the solvent manufacturing processes not polluting.

In particular, the invention aims to propose a process which allows both simple and economical to prepare non-polluting solvents based on naphthenic hydrocarbons. Naphthenic hydrocarbons (or naphthenes) are understood to mean hydrocarbon molecules comprising at least one saturated ring, also called cyclo-paraffins.

To this end, the invention aims at a process of preparation according to claim 1. The process according to the invention has a first advantage: to be simpler and more effective than the processes known for the preparation of naphthenic hydrocarbons. In fact, it does not require specific investments in the refineries and does not require the intervention of solvents that may be expensive products. With respect to prior art processes, the process of the invention allows lowering the manufacturing costs of the naphthene-rich solvents. The process according to the invention has a second very important advantage: that of allowing the recovery of refinery fractions increasingly difficult to valorize. These are gasoline and diesel fractions from catalytic cracking, which are rich in aromatic hydrocarbons and are difficult to integrate into the fuel reserves because of the increasingly stringent specifications for the authorized levels of aromatic compounds.

This process therefore has a double advantage: on the one hand, it uses a fraction difficult to value due to its content of aromatic compounds and, on the other hand, leads to a product with high added value, non-toxic and respect the environment .

In the known manner, the petroleum and petrochemical industries resort to processes for conversion of heavy hydrocarbon fractions, wherein the high molecular weight hydrocarbon molecules with high boiling point are cleaved into smaller molecules which can boil over temperature ranges suitable for the intended use. 7

Among these, certain conversion processes are carried out without the use of hydrogen. Non-hydrogen conversion processes include, but are not limited to, cracking processes, whether thermal or catalytic, visbreaking processes or steam cracking processes.

In particular, the oil industry has such fluid state cracking processes. In this type of process, the hydrocarbon charge, generally sprayed in the form of fine droplets, is brought into contact with high temperature heat conducting particles circulating in the reactor in the fluidized bed form, i.e., in more or less dense suspension in the of a gaseous fluid which ensures or assists in its transport. Upon contact with the hot particles, vaporization of the charge occurs, followed by cracking of the hydrocarbon molecules. The cracking reaction is of the thermal type when the particles have only a heat transfer function. It is of the catalytic type when the particles also have a catalytic function, i.e. have active sites which favor the cracking reaction. This is the case in the catalytic cracking process in the fluid state (referred to as the FCC process, from English " Fluid Catalytic

Cracking "). Steam cracking, used in petrochemicals, is a hydrocarbon conversion process which is carried out without addition of hydrogen and without catalyst, but in the presence of water vapor and at high temperature (about 800 ° C). It allows, in particular, from light hydrocarbons, called naphthas, to produce ethylene and propylene. The first step of the process according to the invention is to remove from a column of fractionation of the effluents of a non-hydrogen conversion unit a hydrocarbon fraction, the distillation range of which is in the range from 100 ° C to 400 ° C.

Preferably, the hydrocarbon fraction withdrawn during this first step is from a catalytic cracking unit or comes from a steam cracking unit.

Also preferably, the hydrocarbon fraction withdrawn during this first step has a distillation range in the range of from 135 ° C to 330 ° C.

More preferably, the hydrocarbon fraction withdrawn during this first step has a distillation range in the range of from 145 ° C to 260 ° C. The hydrocarbon fraction from the catalytic cracking selected for the first step of the process of the invention is rich in unsaturated cyclic compounds. Contains at least 70% by volume of unsaturated cyclic compounds.

Namely, the unsaturated cyclic compounds present in this moiety may be aromatic compounds, thiophenic or benzothiophene compounds, unsaturated cyclic nitrogen compounds, cyclic unsaturated sulfur compounds, cycloolefins. 9

Preferably, the unsaturated cyclic compounds are aromatic compounds or cycloolefins. The second step of the process according to the invention consists in subjecting the hydrocarbon fraction withdrawn from the catalytic cracking unit to a hydrodesulfurization in the presence of a catalyst and in the presence of hydrogen.

This step is intended to desulfurize, at least partially, the hydrocarbon fraction from catalytic cracking, so as to eliminate the compounds that could constitute poisons for the hydrogenation catalyst used during the third step of the process. The hydrodesulfurization catalyst used consists of a solid support and an active phase. The active phase contains at least one metal from the periodic table of the elements.

Preferably, the metal may be selected from Group VI metals, Group VIII metals or mixtures thereof, on a support based on one or more refractory oxides, preferably alumina, silica and / or their mixtures.

These hydrodesulfurization catalysts well known to the person skilled in the art may be used during this step but after sulfation. For example, cobalt-molybdenum (CoMo), nickel-molybdenum (NiMo) or nickel-tungsten type catalysts may be used, which are sulfurised in situ or ex situ. 10

Another particularly effective catalyst for carrying out the hydrodesulfurization step according to the process of the invention is, on the one hand, a solid support comprising a silica-alumina dispersed in an alumina binder and, on the other hand, by a phase active compound comprising a combination of platinum and palladium containing at least 0.1% by weight of each of them and preferably from 0.25 to 1% by weight.

Preferably, the solid support contains between 15% and 30% by weight of alumina binder relative to the total weight of the silica-alumina and the alumina binder and the silica-alumina contains between 15% and 30% by weight of alumina. The hydrodesulphurisation step is carried out under conditions which provide for a desulphurized hydrocarbon fraction having a sulfur content of less than or equal to 50 ppm by weight.

Preferably, the hydrodesulfurization is carried out under conditions which provide for a desulphurized hydrocarbon fraction having a sulfur content of less than or equal to 10 ppm by weight, and even more preferably less than or equal to 2 ppm by weight. The third step of the process of the invention is to subject the desulphurized hydrocarbon fraction to controlled hydrogenation in the presence of a catalyst and hydrogen.

This step is intended to at least partially convert the unsaturated cyclic hydrocarbons present in a large amount into the desulphurized fraction into naphthenic compounds. The hydrogenation catalyst used consists of a solid support and an active phase. The solid support may be any refractory mineral oxide and, advantageously, selected from silicas, aluminas and silicas-aluminas.

Preferably, the solid support is an inactivated alumina. The hydrogenating metal is nickel. The nickel content of the hydrogenation catalyst is between 10% and 70% by weight.

Preferably, it is comprised between 20% and 30% by weight in the very dispersed phase (catalyst obtained by impregnation) and from 40% to 65% by weight in the classical phase (catalyst obtained by extrusion). The controlled hydrogenation step takes place at a temperature in the range of 80 ° C to 250 ° C, preferably in the range of 100 ° C to 240 ° C. The ratio H2 / HC (hydrogen for hydrocarbons) ranges from 100 to 1000 inclusive. The hydrogen partial pressure is comprised between 50 and 160,105 Pa.

The hydrogenation conditions are controlled so as to selectively hydrogenate the unsaturated cyclic hydrocarbons to naphthenes.

Preferably, the hydrogenation conditions are controlled so as to selectively hydrogenate the aromatic hydrocarbons to naphthenes.

According to another feature of the process of the invention, the controlled hydrogenation step is followed by a fractionation step by distillation of the hydrogenated fraction, to obtain various fractions having narrower distillation ranges.

Thus, according to a preferred embodiment of the invention, hydrocarbon fractions from the controlled hydrogenation step can be selected, such as a light fraction whose distillation range is in the range of 100-205 ° C, an intermediate fraction which distillation range is in the range of 170-270 ° C and a heavy fraction whose distillation range is in the range of 200-240 ° C.

Even more preferably, the fractionation step may be to select fractions having distillation ranges of less than or equal to 55øC, preferably less than or equal to 30øC. The choice of finer hydrocarbon fractions allows to obtain final products having specific properties, which can find diverse applications and be valued in different domains. 13

Products from the light fraction, the distillation range of which is in the range of 100-205Â ° C, may be evaluated in particular as solvents, for example for paint inks and varnishes. They can also find applications for degreasing metals.

The products from the intermediate fraction, the distillation range of which is in the range of 170-270 ° C, may in particular include applications such as paint and varnish solvents, as metal degreasing agents or as aluminum rolling agents.

Finally, products from the heavy fraction, the distillation range of which is in the range of 200-400 ° C, may be used in particular as printing ink solvents or as substitutes for silicone oils in silicone mastics.

The applications of the products obtained by the process of the invention are not limited to the uses mentioned hereinbefore.

DETAILED DESCRIPTION OF THE INVENTION The invention will be better understood with the aid of the attached Figure 1, schematically representing a naphthenic solvent manufacturing device according to the process of the invention. 14

In a first step, the hydrocarbonaceous charge containing at least 70% by volume of unsaturated cyclic compounds is withdrawn, via line 5, from a column 1 of the effluent fractionation of a catalytic cracking unit not shown in the figure. The filler rich in unsaturated cyclic compounds is injected by line 5 into a hydrodesulphurisation unit 2, where it undergoes a desulphurisation in the presence of a desulphurisation and hydrogen catalyst, to produce an at least partially desulphurised fraction, taken along line 6. The desulphurized is injected via line 6 into a controlled hydrogenation unit 3 undergoing controlled hydrogenation in the presence of a hydrogenation and hydrogenation catalyst to produce a hydrocarbon fraction containing at least 70% by weight of naphthenes taken along line 7 .

This naphthene-rich hydrocarbon fraction can then be sent by line 7 to a separation column 4 to be fractionated into several fractions having narrower distillation ranges. A light fraction can be withdrawn by line 8, an intermediate fraction by line 9 and a fraction weighed by line 10, to be then valued in different applications. 15

EXAMPLE The following example is intended solely to illustrate the invention and is not intended to limit its scope.

A hydrocarbon fraction from catalytic cracking, the characteristics of which are set forth in Tables 1 and 2 below, are according to the process of the invention. TABLE 1: ASTM D86 Distillation of the fraction to be treated

Fraction of hydrocarbons from catalytic cracking% distilled Temperature (volume) (° C) Starting point 142 5 154 10 158 50 177 70 185 90 203 95 219 End point 234 16 TABLE 2: Characteristics of the fraction to be treated

Fraction of hydrocarbons from catalytic cracking Characteristics Values Density at 15 ° C 0,8417 Content of naphthenes (wt%) wt Aromatic content (wt%) 75.3 Content of cycloolefins (wt%) 3, 2 bromine number (mg Br / 100 g) 3499 Sulfur compound content (wt.%) 0.076 Aniline point (° C) 23

The operating conditions of the different treatment steps are presented in Table 3. TABLE 3: Operating conditions HIDRODESULFURATION Catalyst C0M0 on alumina Partial pressure H2 (10b Pa) 58.6 Temperature (° C) 315 CONTROLLED HYDROGENATION Catalyst Ni on alumina Partial pressure of H2 (10b Pa) 51 Temperature (° C) 130 H2 / HC Ratio (Nl / liter) 219 17

In the case of this example, the treated fraction was not fractionated on a distillation column after the controlled hydrogenation step.

The characteristics of the obtained hydrocarbon fluid are presented in Table 4. TABLE 4: Characteristics of the obtained hydrocarbon fluid

Characteristics Values Density at 15 ° C 0.7856 Content of naphthenes (wt%) 86.5 Aromatics content (ppmw) 100 Bromine index (mg Br / 100 g) 36 Content of sulfur compounds (wt% ) 0.4 Aniline point (° C) 56.4

In Tables 2 and 4: - The aniline point is determined by the ISO 2977 method. - The bromine number is determined by the ASTM method D2710.

This method determines the rate of bromine-reactive compounds present in a hydrocarbon moiety. It thus allows determining the rate of unsaturated compounds present in the fraction.

When the hydrocarbon fraction is rich in unsaturated compounds, the higher the bromine number. 18

The results of Table 4 above show that the process of the invention allowed to manufacture from a very aromatic fraction (75.3% by weight) a hydrocarbon product capable of being recovered as a non-toxic and non-polluting solvent.

In fact, the final product obtained contains only 100 ppm by weight of aromatics and less than 1 ppm by weight of sulfur compounds. It is free of the toxic compounds present in the initial fraction.

A large part of the unsaturated compounds present in the initial fraction disappeared, in particular, the aromatic compounds, transformed into naphthenic compounds.

This high content of naphthenic compounds, however, allows it to have a good solvent power and thus be appreciated as such.

Lisbon, June 21, 2013 19

Claims (14)

Process for the preparation of a hydrocarbon fluid containing at least 70% by weight of naphthenic hydrocarbons and having an aromatic hydrocarbon content of less than or equal to 500 ppm by weight, characterized in that it comprises: (a) at least one withdrawing from an effluent fractionating column of a non-hydrogen conversion unit a hydrocarbon fraction having a distillation range in the range of 100 ° C to 400 ° C and containing at least 70 % by volume of unsaturated cyclic hydrocarbons, (b) at least one hydrodesulphurisation step of said fraction, so as to obtain a desulphurised fraction having a sulfur content of less than 50 ppm by weight, (c) at least one controlled hydrogenation step of said desulphurized fraction in the presence of hydrogen and a catalyst comprising from 10% to 70% by weight of nickel deposited on a solid support at a temperature of from 80 ° C to 250 ° C and a hydrogen partial pressure of from 50 to 160,105 Pa, the hydrogenation conditions being selected in order to obtain a hydrocarbon fluid having an aromatic hydrocarbon content of less than or equal to 500 ppm by weight, 1 (d) at least one recovery step of hydrocarbon fluid containing at least 70% by weight of naphthenic hydrocarbons and having an aromatic hydrocarbon content of less than or equal to 500 ppm by weight from step c ). Process according to claim 1, characterized in that the non-hydrogen conversion unit is a catalytic cracking unit. A process according to claim 1, characterized in that the non-hydrogen conversion unit is a steam cracking unit. Process according to any one of claims 1 to 3, characterized in that the hydrocarbon fraction withdrawn during step (a) has a distillation range in the range of from 135 ° C to 330 ° C. Process according to any one of claims 1 to 3, characterized in that the hydrocarbon fraction withdrawn during step (a) has a distillation range in the range of from 145 ° C to 260 ° C. Process according to any one of Claims 1 to 5, characterized in that the unsaturated cyclic hydrocarbons present in the hydrocarbon fraction withdrawn during step (a) belong to the group consisting of the aromatic compounds, thiophenic compounds, benotiophenic compounds, unsaturated cyclic sulfur compounds, unsaturated cyclic nitrogen compounds, cyclo-olefins, and mixtures thereof. Process according to any one of claims 1 to 6, characterized in that the unsaturated cyclic hydrocarbons present in the hydrocarbon fraction withdrawn in step (a) are aromatic compounds and / or cycloolefins. Process according to any one of claims 1 to 7, characterized in that the hydrodesulfurization step to which the hydrocarbon fraction is subjected leads to a desulphurized fraction having a sulfur content of less than or equal to 10 ppm by weight. Process according to any one of claims 1 to 7, characterized in that the hydrodesulfurization step to which the hydrocarbon fraction is subjected leads to a desulphurized fraction having a sulfur content of less than or equal to 2 ppm by weight. A process according to any one of claims 1 to 9, characterized in that the hydrodesulfurization catalyst comprises at least one metal selected from the group VI metals, group VIII metals or mixtures thereof, on a support based on one or more refractory oxides, preferably alumina, silica and / or mixtures thereof. Process according to any one of claims 1 to 10, characterized in that the hydrodesulfurization catalyst comprises: an active phase comprising a combination of platinum and palladium containing at least 0.1% by weight of each of them and, preferably from 0.25% to 1% by weight, and a solid carrier comprising a silica-alumina dispersed in an alumina binder, said carrier containing from 15% to 30% by weight of alumina binder in relation to total weight of the silica-alumina and the alumina binder, and said silica-alumina containing between 15% and 30% by weight of alumina. Process according to any one of claims 1 to 11, characterized in that the controlled hydrogenation is followed by a fractionation step by distillation of the hydrogenated fraction to obtain at least a narrow fraction having a distillation range whose amplitude is lower or equal to 55 ° C. Process according to claim 12, characterized in that the fractionation step is carried out in order to obtain at least a narrow fraction having a distillation range whose amplitude is less than or equal to 30 ° C. A process according to any one of claims 1 to 13, characterized in that the step of fractionating the hydrocarbon fluid recovered in step (d) allows to select: a light fraction whose distillation range is in the range of 100-205 ° C; 4 is an intermediate fraction whose distillation range is in the range 170-270 ° C; a heavy fraction whose distillation range is in the range of 200-400 ° C. Lisbon, June 21, 2013 5