EP0416979A1 - Process for fixed bed sweetening of petroleum fractions - Google Patents
Process for fixed bed sweetening of petroleum fractions Download PDFInfo
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- EP0416979A1 EP0416979A1 EP90402387A EP90402387A EP0416979A1 EP 0416979 A1 EP0416979 A1 EP 0416979A1 EP 90402387 A EP90402387 A EP 90402387A EP 90402387 A EP90402387 A EP 90402387A EP 0416979 A1 EP0416979 A1 EP 0416979A1
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- temperature
- support
- water
- load
- mercaptans
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G25/00—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G27/00—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation
- C10G27/04—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen
- C10G27/10—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen in the presence of metal-containing organic complexes, e.g. chelates, or cationic ion-exchange resins
Definitions
- the present invention relates to the softening in a fixed bed of petroleum fractions, by catalytic oxidation to disulphides of the mercaptans which they contain.
- such an oxidation can be obtained simply by mixing the petroleum fraction to be treated and an aqueous solution of an alkaline base, to which a catalyst based on a metal chelate is added, in the presence of an oxidizing agent.
- the petroleum cut and the aqueous solution of the alkaline base are not miscible and it is at the interface of the two liquid phases that the mercaptans are converted to disulfides (see French patent No. 1,249,134).
- the oxidizing agent generally air, is mixed with the cut to be softened.
- the alkaline base usually an aqueous sodium hydroxide solution, is introduced either continuously or intermittently into the reaction medium to maintain the alkaline conditions and the aqueous phase necessary for the oxidation reaction.
- the metal chelate used as a catalyst, is generally a metal phthalocyanine (see French patent n ° 1,301,844).
- the reaction is carried out at a pressure generally between 5 and 30.105 Pascals, at a Gomprise temperature between 20 and 40 ° C.
- a pressure generally between 5 and 30.105 Pascals
- Gomprise temperature between 20 and 40 ° C.
- aqueous sodium hydroxide or a strong base
- the present invention aims to remedy all these drawbacks by proposing a process for softening an oil cut, by catalytic oxidation of mercaptans, requiring neither the use of an inorganic or organic anhydrous base, nor the use of a desiccant mixed with the support, nor the periodic drying of the support using a solvent.
- the Applicant has, in fact, observed that, since the oxidation reaction of the mercaptans can take place in the absence of a basic solution, it becomes possible to carry out this reaction without damage to the catalyst at a higher temperature than according to prior art, that is to say at a temperature generally above 40 ° C.
- This action on the temperature results in a modification of the solubility of the water in the charge and, consequently, a modification of the quantity of water present on the surface of the catalytic support. It is then possible to maintain the catalytic properties at their optimum level.
- the subject of the invention is therefore a process for softening an oil cut in the presence of an oxidizing agent, by catalytic oxidation of the mercaptans which it contains, in the presence of a support in a fixed bed impregnated with a metal chelate. and in the absence of an aqueous base, this process being characterized in that the water content of the support is maintained within a range of predetermined values by action on the solvent power of the filler with respect to the water of the support, depending on the temperature, and in that the temperature of the charge is fixed at a value sufficient to dissolve the reaction water resulting from the transformation of the mercaptans into disulfides.
- the temperature of the load is thus chosen so as to maintain the water content of the support between between 0.1 and 50% by weight of the support and, preferably, between 1 and 25% by weight of the latter.
- This range of predetermined values of water contents of the support will depend, of course, on the very nature of the catalytic support used during the softening reaction. Indeed, the Applicant has established that, if many catalytic supports are capable of being used without aqueous sodium hydroxide (or without base), their activity will only manifest themselves when their water content (also called hydration level of the support) is kept within a relatively narrow range of values, variable depending on the supports, but apparently linked to the content of the silicate support and to the structure of its pores.
- the optimum value of the hydration rate of the support determined experimentally, it is possible, by means known in the art, to adapt the initial water content of the support to this value: - to lower the initial rate of hydration of the support, it is possible, among other means, either to raise the temperature of the charge in the reactor, or to inject continuously or discontinuously a quantity of polar solvent miscible with water, or else circulating in the reactor a hot fluid such as air; - Conversely, to increase this rate, it is possible either to lower the temperature of the reactor, or to send a determined quantity of water into it.
- the temperature of the petroleum cut will generally be kept above 30 ° C and preferably between 40 and 140 ° C; the necessary heat can be provided by any means of a type known per se, but preferably it will be provided by heat exchange upstream of the reaction zone.
- the catalytic oxidation reaction will be advantageously carried out at a higher temperature. at 30 ° C and preferably between 40 and 120 ° C. These conditions are aimed in particular at the softening of petroleum fractions such as kerosene or so-called catalytic or direct distillation gasolines.
- the catalytic oxidation reaction will be carried out at a temperature higher than 40 ° C and preferably between 50 and 140 ° C. These conditions are aimed in particular at the softening of petroleum cuts such as light petrol.
- the optimum level of hydration of the support on which the catalytic activity depends will be maintained at a determined value, generally between 1 and 25% by weight, despite possible variations in the charge, for example by fluctuating the temperature of a few degrees around an equilibrium temperature, depending on whether the support itself tends to hydrate or dehydrate.
- This rate can also be maintained by substantially raising the reaction temperature and by injecting a certain amount of water, which can vary depending on the water and mercaptan contents of the feed.
- a possible alternative will consist, for example, in carrying out the reaction at a temperature a few degrees lower than the equilibrium temperature mentioned above and in sending, periodically, or continuously, a determined quantity of poorly hydrated filler to a higher temperature.
- means will be used to measure the water content of the feed and of the effluent, or of the catalytic support, as well as the mercaptan contents of the feed. and effluent.
- Another means, easy to implement, consists in using two probes for continuous measurement of the water content of the feed, the first being located upstream of the catalytic bed, the second downstream of the latter.
- the probes making it possible to continuously measure the water content of the feed, it is possible to use commercial probes, such as those sold by the Endress Hauser Company, or capacitive probes of the type described in French patent application No. 2.512 .958.
- the difference between the content measured downstream and that measured upstream then makes it easy to determine, taking into account the quantity of mercaptans transformed into disulphides, by how much increases or decreases the water content of the support.
- a modification of the reaction temperature (or of the quantity of additional water injected) then makes it possible to make the water content of the catalytic support in the reactor substantially constant.
- a first advantage of the present invention follows from the very principle of the reaction, which is linked to the absence of base or of caustic solution in the feed and in the effluents: on the one hand, there is no longer any need to separate the bases, neither to reprocess them, nor to have an expensive unit of destruction of these; on the other hand, the absence of base, even in trace amounts in the treated petroleum charges, makes the latter excellent products for subsequent direct use.
- a second advantage of the present invention results from the fact that the reaction water is entrained by the petroleum charge itself during the softening. There is therefore no longer any need for costly drying of the support by injecting solvents into the feed, or by using a desiccant in the catalytic bed.
- a third advantage of the present invention results from the fact that the softening reaction is carried out at a higher temperature than according to the prior art: the kinetics of the reaction are improved, and it becomes possible to carry out the reaction continuously at a hourly space velocity greater than that of the prior art.
- This hourly space speed may be of the order of 1 to 8 v.v.h. (charge volume per catalyst volume and per hour) for kerosene type charges and of the order of 1 to 10 v.v.h. for petrol type loads. This results in a significant saving on the construction costs of the softening unit, since the size thereof can be reduced accordingly.
- reaction kinetics being improved, it is also possible to treat more refractory or heavier fillers which are difficult to soften according to the prior art, or to carry out the softening of the mercaptans continuously where only discontinuous techniques were applicable. until now.
- a fourth advantage of the present invention finally results from the fact that the softening reaction is carried out in homogeneous phase, without the formation of gums, which leads to a reduction in washing and maintenance costs, and a simplification of the equipment located downstream. of unity.
- the process according to the invention is well suited to the softening of all petroleum cuts and, in particular, the softening of petrol and kerosene. Indeed, these petroleum fractions contain only very little water (an amount generally less than 500 ppm) and, consequently, the rise in temperature necessary to dissolve the water molecules generated in situ during the reaction of softening will be kept within acceptable limits.
- the petroleum charge to be treated contains relatively large quantities of mercaptans, for example for charges whose mercaptan content is greater than 300 ppm, it will be possible to compensate for the formation in situ of a corresponding quantity of molecules d water, for example by drying the charge beforehand on molecular sieves, (or by cooling it, then by decanting it), in order to limit as much as possible its initial water content.
- reaction conditions could, for example, be as follows: - temperature : 40 to 140 ° C, - pressure: 105 to 30.105 Pascals, - quantity of oxidizing agent (air): 1 to 31 / kg of mercaptans, - hourly space velocity in vvh (charge volume per catalyst volume and per hour): 1 to 10, - water content of the support (% by weight): 1 to 25.
- supports based on activated carbon on alumina, of clay, aluminosilicates, silicates or mixtures of these.
- any chelate used for this purpose in the prior art especially phthalocyanines, porphyrins or metallic corrines, can be deposited on the support.
- phthalocyanines especially phthalocyanines, porphyrins or metallic corrines
- cobalt phthalocyanine and vanadium phthalocyanine particularly preferred.
- metallic phthalocyanine is used in the form of a derivative of the latter, with particular preference for their commercially available sulfonates, such as, for example, cobalt phthalocyanine disulphonate and mixtures thereof. this.
- This figure represents a diagram of continuous implementation of the method according to the invention.
- the supply of the reactor 1 in petroleum cut to be softened is carried out by line 2, into which the oxidizing agent, for example air, is introduced directly by line 3.
- the treated petroleum cut is evacuated by line 4, which feeds a filter system 5, intended to remove traces of water and nascent sulfur often produced during the oxidation of mercaptans and not retained by the support.
- the treated charge is then transferred by line 6 to a storage enclosure 7.
- measurement probes 8 and 9 placed respectively upstream and downstream of the reactor, make it possible to permanently determine the water and mercaptan contents at the inlet and at the outlet of the reactor 1. It is thus it is possible to continuously check whether the water content of the catalytic support increases or decreases.
- a corrective action can then be carried out by modifying the quantity of heat supplied to the load by a heat exchanger 10 placed on the line 2 upstream of the reactor 1. Part of the heat provided by the exchanger 10 can then be recovered using the exchanger 11 placed on the line 4 downstream of the reactor 1 and from the water formed eliminated at 5.
- Water can optionally be injected into the feedstock through line 12, placed here between the temperature regulation phase at 10 and the catalytic oxidation phase at 1 of the petroleum cut.
- the temperature of the charge at the outlet of the exchanger 10 will be slightly higher than that required to keep the water content of the support equal to its set value, and an additional d water will, for example, be introduced via line 12 to make this content equal to the set value, despite fluctuations in the contents of water and mercaptans or those of the temperature of the charge.
- This embodiment of the invention has the advantage that it is easier to ensure regulation by varying the amount of water injected than by varying the temperature of the charge.
- the implementation of the invention proves to be particularly effective in softening petroleum fractions, even those deemed to be difficult to treat.
- the catalytic support used in this example was prepared as described in European patent application No. 252,853. After impregnation of the support with a sulfonated cobalt phthalocyanine of the type marketed by the French company PROCATALYSE under the name "LCPS", this catalyst is in the form of an aggregate (with a specific surface of approximately 50 m2 / g, which contains mainly about 1.5 kg of chelate per m3 of support This support contains approximately 10% by weight of carbon, 20% by weight of silicon, and 8 to 9% by weight of potassium salts in the form of insoluble salts.
- the charge C1 is a charge of the kerosene type, resulting from a mixture of isthmus-cactus crudes and Mayan crude, containing approximately 80 ppm of mercaptans and 100 ppm of water; -
- the charge C2 is a gasoline type charge, containing approximately 300 ppm of mercaptans and 150 ppm of water.
- C1 C2 - aromatic compounds (% by volume): 20 60 - olefins (% by volume): ⁇ 5 20 - saturated hydrocarbons (% by volume): 78 20 - mercaptans content (ppm by volume): 80 300 - water content at 40 ° C (ppm by weight): 100 * 150 * The load coming here from a prewash unit, this value corresponds to the maximum solubility of water in the load at this temperature.
- Air is used as the oxidizing agent, and no basic aqueous solution is used.
- the mercaptan content of the treated charge C1 is less than 5 ppm during the first sixty days approximately, then that the mercaptan content of the effluents rises gradually and exceeds 10 ppm after 90 days, due to the progressive saturation in water of the catalytic support; it is then easy to see that the reaction water has been captured by the support, the hydration rate of which has risen to more than 10%.
- the operating conditions are then modified to carry out the T3 test in accordance with the method according to the invention: it is found that the mercaptan content of the treated charge C1 always remains below 5 ppm, after 300 days of operation. Indeed, the hydration rate of the support has remained substantially constant, due to the temperature rise from 40 to 45 ° C, which allows to remove with the charge all the reaction water from the conversion of mercaptans to disulfides .
- reaction conditions are again modified to carry out the T4 test, also in accordance with the method according to the invention: it is also found that the mercaptan content of the treated C1 charge always remains less than 5 p.p.m., even after 300 days of operation. Indeed, the hydration rate of the support is maintained at a constant value of around 6%, despite the sharp increase in temperature from (from 45 to 80 ° C) and in hourly space speed (from 1 to 4 vvh) thanks to a sufficient injection of water into the feed (+ 577 ppm) so that, despite the significant increase in its solvent power at 80 ° C, the feed can no longer dissolve in the reactor except the amount of reaction water produced.
- T5 T6 - reaction temperature (° C): 40 70 - pressure (pascals): 6.105 6.105 - air flow (1): 1.8 1.8 - initial water content of the charge: 150 815 - water content of effluents (ppm): 150 900 - hourly space velocity (vvh): 0.8 5 - initial hydration rate (% by weight of): 5 11 - final hydration rate (% by weight of): 11 6 - cycle time (days): 28 > to 300
- reaction conditions are therefore modified to use those described in T6, and it can be seen that, as with kerosene feedstocks, the process according to the invention makes it possible to keep the mercaptan content constantly below 10 ppm, by an action on the solvent power of the load as a function of the temperature, similar to the T4 test described previously.
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Abstract
L'invention concerne un procédé d'adoucissement d'une coupe pétrolière en présence d'un agent oxydant, par oxydation catalytique des mercaptans qu'elle contient, en présence d'un support en lit fixe imprégné d'un chélate métallique et en l'absence d'une base aqueuse. Selon l'invention, la teneur en eau du support est maintenue dans un intervalle de valeurs prédéterminées par action sur le pouvoir solvant de la charge à l'égard de l'eau du support, en fonction de la température. Pas de figure d'abrégé.The invention relates to a process for softening an oil cut in the presence of an oxidizing agent, by catalytic oxidation of the mercaptans which it contains, in the presence of a fixed bed support impregnated with a metal chelate and in l absence of an aqueous base. According to the invention, the water content of the support is maintained within a range of predetermined values by acting on the solvent power of the filler with respect to the water of the support, as a function of the temperature. No abstract figure.
Description
La présente invention concerne l'adoucissement en lit fixe de coupes pétrolières, par oxydation catalytique en disulfures des mercaptans qu'elles contiennent.The present invention relates to the softening in a fixed bed of petroleum fractions, by catalytic oxidation to disulphides of the mercaptans which they contain.
Dans son principe, une telle oxydation peut être obtenue simplement en mélangeant la coupe pétrolière à traiter et une solution aqueuse d'une base alcaline, dans laquelle on ajoute un catalyseur à base d'un chélate métallique, en présence d'un agent oxydant. La coupe pétrolière et la solution aqueuse de la base alcaline ne sont pas miscibles et c'est à l'interface des deux phases liquides que les mercaptans sont convertis en disulfures (voir le brevet français n° 1.249.134).In principle, such an oxidation can be obtained simply by mixing the petroleum fraction to be treated and an aqueous solution of an alkaline base, to which a catalyst based on a metal chelate is added, in the presence of an oxidizing agent. The petroleum cut and the aqueous solution of the alkaline base are not miscible and it is at the interface of the two liquid phases that the mercaptans are converted to disulfides (see French patent No. 1,249,134).
Avec des mercaptans plus difficilement oxydables, il est préférable de traiter la coupe pétrolière à l'aide d'un catalyseur supporté, en présence d'une base alcaline et d'un agent oxydant, et l'on désigne ce procédé par l'appellation de "procédé d'adoucissement en lit fixe". L'agent oxydant, généralement de l'air, est mélangé à la coupe à adoucir. La base alcaline, habituellement une solution aqueuse de soude, est introduite soit en continu, soit par intermittence, dans le milieu réactionnel, pour maintenir les conditions alcalines et la phase aqueuse nécessaires à la réaction d'oxydation. Le chélate métallique, utilisé comme catalyseur, est généralement une phtalocyanine métallique (voir le brevet français n° 1.301.844). La réaction est pratiquée à une pression généralement comprise entre 5 et 30.10⁵ Pascals, à une température Gomprise entre 20 et 40°C. Il est toutefois bien connu de l'homme de l'art que, lorsque l'on effectue une telle réaction en milieu oxydant avec de la soude (ou une base forte) aqueuse, mais à température plus élevée que la température ambiante, la stabilité du catalyseur à base de chélate métallique diminue rapidement au détriment de la réaction d'adoucissement.With mercaptans which are more difficult to oxidize, it is preferable to treat the petroleum fraction using a supported catalyst, in the presence of an alkaline base and an oxidizing agent, and this process is designated by the designation "fixed bed softening process". The oxidizing agent, generally air, is mixed with the cut to be softened. The alkaline base, usually an aqueous sodium hydroxide solution, is introduced either continuously or intermittently into the reaction medium to maintain the alkaline conditions and the aqueous phase necessary for the oxidation reaction. The metal chelate, used as a catalyst, is generally a metal phthalocyanine (see French patent n ° 1,301,844). The reaction is carried out at a pressure generally between 5 and 30.10⁵ Pascals, at a Gomprise temperature between 20 and 40 ° C. However, it is well known to those skilled in the art that, when such a reaction is carried out in an oxidizing medium with aqueous sodium hydroxide (or a strong base), but at a temperature higher than room temperature, the stability metal chelate catalyst decreases rapidly at the expense of the softening reaction.
Par ailleurs, il convient de renouveler la solution sodique qui s'épuise, d'une part, en raison des impuretés provenant de la charge, qui se dissolvent dans cette solution et la rendent impropre au recyclage et, d'autre part, en raison de la variation de la concentration de la base, qui diminue du fait de l'apport d'eau par la charge et de la transformation des mercaptans en disulfures.In addition, it is advisable to renew the sodium solution which runs out, on the one hand, because of the impurities from the load, which dissolve in this solution and make it unsuitable for recycling and, on the other hand, due to the variation in the concentration of the base, which decreases due to the supply of water by the load and the transformation of mercaptans into disulfides.
Pour remédier à cet inconvénient, il a été proposé (voir les brevets FR 2.343.043, U.S. 4.498.978 et U.S. 4.502.949) de supprimer l'utilisation de soude (ou de base) aqueuse. Toutefois, pour que la réaction puisse se dérouler normalement, les sites actifs du support doivent alors se trouver en contact avec les mercaptans présents dans la charge pétrolière, ce qui suppose un milieu homogène et donc l'absence d'une solution aqueuse. Or il apparaît que les molécules d'eau déjà présentes dans la charge et surtout celles produites au cours de la réaction favorisent l'apparition à la surface du catalyseur d'une telle solution aqueuse, dont le maintien au-delà d'un certain seuil conduit à un abaissement de l'activité catalytique. Il a donc été proposé soit d'intégrer dans le support un dessicant solide (brevet U.S. 4.498.978), soit de résorber périodiquement cette phase aqueuse par séchage du catalyseur à l'aide d'un solvant polaire miscible à l'eau tel qu'un alcool (brevet FR 88.16.907). Toutefois, ces solutions, si elles s'avèrent efficaces, conduisent nécessairement à des coûts d'exploitation relativement élevés.To overcome this drawback, it has been proposed (see patents FR 2,343,043, U.S. 4,498,978 and U.S. 4,502,949) to eliminate the use of aqueous sodium hydroxide (or base). However, for the reaction to proceed normally, the active sites of the support must then be in contact with the mercaptans present in the petroleum charge, which supposes a homogeneous medium and therefore the absence of an aqueous solution. However, it appears that the water molecules already present in the feed and especially those produced during the reaction favor the appearance on the surface of the catalyst of such an aqueous solution, the maintenance of which exceeds a certain threshold. leads to a lowering of the catalytic activity. It has therefore been proposed either to integrate into the support a solid desiccant (US patent 4,498,978), or to periodically resorb this aqueous phase by drying the catalyst using a polar solvent miscible with water such as 'an alcohol (patent FR 88.16.907). However, these solutions, if they prove to be effective, necessarily lead to relatively high operating costs.
La présente invention vise à remédier à tous ces inconvénients en proposant un procédé d'adoucissement d'une coupe pétrolière, par oxydation catalytique des mercaptans, ne nécessitant ni l'utilisation d'une base anhydre minérale ou organique, ni l'usage d'un dessicant en mélange avec le support, ni le séchage périodique du support à l'aide d'un solvant.The present invention aims to remedy all these drawbacks by proposing a process for softening an oil cut, by catalytic oxidation of mercaptans, requiring neither the use of an inorganic or organic anhydrous base, nor the use of a desiccant mixed with the support, nor the periodic drying of the support using a solvent.
La Demanderesse a, en effet, observé que, puisque la réaction d'oxydation des mercaptans peut se dérouler en l'absence d'une solution basique, il devient possible de réaliser cette réaction sans dommage pour le catalyseur à une température plus élevée que selon l'art antérieur, c'est-à-dire à une température généralement supérieure à 40°C. De cette action sur la température (action qui peut être continue ou momentanée), résulte une modification de la solubilité de l'eau dans la charge et, par conséquent, une modification de la quantité d'eau présente à la surface du support catalytique. Il est alors possible de maintenir les propriétés catalytiques à leur niveau optimum.The Applicant has, in fact, observed that, since the oxidation reaction of the mercaptans can take place in the absence of a basic solution, it becomes possible to carry out this reaction without damage to the catalyst at a higher temperature than according to prior art, that is to say at a temperature generally above 40 ° C. This action on the temperature (action which can be continuous or momentary) results in a modification of the solubility of the water in the charge and, consequently, a modification of the quantity of water present on the surface of the catalytic support. It is then possible to maintain the catalytic properties at their optimum level.
L'invention a donc pour objet un procédé d'adoucissement d'une coupe pétrolière en présence d'un agent oxydant, par oxydation catalytique des mercaptans qu'elle contient, en présence d'un support en lit fixe imprégné d'un chélate métallique et en l'absence d'une base aqueuse, ce procédé étant caractérisé en ce que la teneur en eau du support est maintenue dans un intervalle de valeurs prédéterminées par action sur le pouvoir solvant de la charge à l'égard de l'eau du support, en fonction de la température, et en ce que la température de la charge est fixée à une valeur suffisante pour solubiliser l'eau de réaction résultant de la transformation des mercaptans en disulfures.The subject of the invention is therefore a process for softening an oil cut in the presence of an oxidizing agent, by catalytic oxidation of the mercaptans which it contains, in the presence of a support in a fixed bed impregnated with a metal chelate. and in the absence of an aqueous base, this process being characterized in that the water content of the support is maintained within a range of predetermined values by action on the solvent power of the filler with respect to the water of the support, depending on the temperature, and in that the temperature of the charge is fixed at a value sufficient to dissolve the reaction water resulting from the transformation of the mercaptans into disulfides.
La température de la charge est ainsi choisie de manière à maintenir la teneur en eau du support entre entre 0,1 et 50% en poids du support et, de préférence, entre 1 et 25% en poids de celui-ci.The temperature of the load is thus chosen so as to maintain the water content of the support between between 0.1 and 50% by weight of the support and, preferably, between 1 and 25% by weight of the latter.
Cet intervalle de valeurs prédéterminées de teneurs en eau du support dépendra, bien entendu, de la nature même du support catalytique utilisé lors de la réaction d'adoucissement. En effet, la Demanderesse a établi que, si de nombreux supports catalytiques sont susceptibles d'être utilisés sans soude (ou sans base) aqueuse, leur activité ne se manifestera que lorsque leur teneur en eau (également appelée taux d'hydratation du support) est maintenue dans un intervalle de valeurs relativement étroit, variable suivant les supports, mais apparemment lié à la teneur du support en silicate et à la structure de ses pores.This range of predetermined values of water contents of the support will depend, of course, on the very nature of the catalytic support used during the softening reaction. Indeed, the Applicant has established that, if many catalytic supports are capable of being used without aqueous sodium hydroxide (or without base), their activity will only manifest themselves when their water content (also called hydration level of the support) is kept within a relatively narrow range of values, variable depending on the supports, but apparently linked to the content of the silicate support and to the structure of its pores.
Ainsi, avec des supports catalytiques du type de celui décrit dans la demande de brevet européen N° 252 953, on observe une bonne conversion des mercaptans en disulfures, sans base et sans solution aqueuse, lorsque le taux d'hydratation du support est compris dans un intervalle de 1 à environ 11% en poids (au-dessous de 1%, le support est trop sec, alors qu'au-delà de 11% apparaît une phase aqueuse sur le support).Thus, with catalytic supports of the type described in European patent application No. 252 953, good conversion of the mercaptans to disulfides is observed, without base and without aqueous solution, when the hydration level of the support is included in an interval of 1 to about 11% by weight (below 1%, the support is too dry, while above 11% an aqueous phase appears on the support).
Avec d'autres supports de type aluminosilicates basiques, on peut observer, suivant le type de catalyseur, un élargissement ou au contraire une restriction de cet intervalle. Le même phénomène paraît avoir été observé avec des supports à base de charbon actif (voir brevet U.S. 4.498.978). Il apparaît toutefois que l'intervalle de valeurs du taux d'hydratation d'un tel support à base de charbon actif est trop étroit pour une application industrielle.With other supports of the basic aluminosilicate type, one can observe, depending on the type of catalyst, a widening or, on the contrary, a restriction of this interval. The same phenomenon seems to have been observed with supports based on activated carbon (see U.S. Patent 4,498,978). However, it appears that the range of values of the hydration rate of such a support based on activated carbon is too narrow for industrial application.
Une fois la valeur optimum du taux d'hydratation du support déterminée expérimentalement, il est possible, par des moyens connus dans la technique, d'adapter la teneur initiale en eau du support à cette valeur:
- pour abaisser le taux initial d'hydratation du support, on peut, entre autres moyens, soit élever la température de la charge dans le réacteur, soit injecter en continu ou en discontinu une quantité de solvant polaire miscible à l'eau, soit encore faire circuler dans le réacteur un fluide chaud tel que de l'air;
- inversement, pour augmenter ce taux, on peut soit abaisser la température du réacteur, soit envoyer dans celui-ci une quantité d'eau déterminée.Once the optimum value of the hydration rate of the support determined experimentally, it is possible, by means known in the art, to adapt the initial water content of the support to this value:
- to lower the initial rate of hydration of the support, it is possible, among other means, either to raise the temperature of the charge in the reactor, or to inject continuously or discontinuously a quantity of polar solvent miscible with water, or else circulating in the reactor a hot fluid such as air;
- Conversely, to increase this rate, it is possible either to lower the temperature of the reactor, or to send a determined quantity of water into it.
Au cours de ses travaux sur l'adoucissage des mercaptans en l'absence de toute base et de toute solution aqueuse, la Demanderesse a maintenant établi qu'une fois obtenu le taux désiré d'hydratation du support catalytique dans le lit catalytique, ce taux pouvait être maintenu sensiblement constant durant la réaction d'adoucissement, et ce malgré
- les apports d'eau par la charge, réguliers ou accidentels, surtout lorsque l'unité d'adoucissement est située en aval d'une unité de prélavage,
- l'apparition d'eau réactionnelle (deux molécules de mercaptans donnant lieu à la formation d'une molécule de disulfure et d'une molécule d'eau).During its work on the softening of mercaptans in the absence of any base and any aqueous solution, the Applicant has now established that once the desired rate of hydration of the catalytic support in the catalytic bed has been obtained, this rate could be kept substantially constant during the softening reaction, despite
- the water supplies by the load, regular or accidental, especially when the softening unit is located downstream of a prewash unit,
- the appearance of reaction water (two molecules of mercaptans giving rise to the formation of a molecule of disulfide and a molecule of water).
En effet, en dépit de l'affinité médiocre de l'eau pour les hydrocarbures, le simple fait d'élever la température de la charge dans le réacteur d'adoucissage permet de diminuer le taux d'hydratation du support, malgré l'affinité apparente de celui-ci pour les molécules d'eau. En outre, lorsque les quantités d'eau issue de la réaction sont importantes, il est possible de maintenir l'hydratation du support à une valeur déterminée en régulant la température réactionnelle à des valeurs considérées jusqu'ici comme impraticables, du fait de l'instabilité à ces températures du catalyseur en présence d'une base aqueuse. Ainsi, dès que la teneur en eau du support devient trop importante, on augmente la température de la charge jusqu'à ce que cette teneur revienne à la valeur de consigne; inversement, lorsque ladite teneur tend à décroître au-dessous de cette valeur, on diminue en conséquence la température de la charge.In fact, despite the poor affinity of water for hydrocarbons, the simple fact of raising the temperature of the charge in the softening reactor makes it possible to reduce the hydration rate of the support, despite the affinity apparent of it for water molecules. In addition, when the quantities of water resulting from the reaction are large, it is possible to maintain the hydration of the support at a determined value by regulating the reaction temperature to values considered hitherto considered impracticable, due to the instability at these temperatures of the catalyst in the presence of an aqueous base. Thus, as soon as the water content of the support becomes too high, the temperature of the load is increased until this content returns to the set value; conversely, when said content tends to decrease below this value, the temperature of the charge is consequently reduced.
La température de la coupe pétrolière sera, en général, maintenue supérieure à 30°C et, de préférence entre 40 et 140°C; la chaleur nécessaire pourra être apportée par tout moyen de type connu en soi, mais, de préférence, elle sera apportée par échange thermique en amont de la zone réactionnelle.The temperature of the petroleum cut will generally be kept above 30 ° C and preferably between 40 and 140 ° C; the necessary heat can be provided by any means of a type known per se, but preferably it will be provided by heat exchange upstream of the reaction zone.
Lorsque la charge pétrolière à traiter est, par exemple, une coupe contenant entre 20 et 300 ppm de mercaptans et moins de 150 p.p.m. d'eau soluble dans la charge à traiter, on procèdera avantageusement à la réaction d'oxydation catalytique à une température supérieure à 30°C et, de préférence, comprise entre 40 et 120°C. Ces conditions visent en particulier l'adoucissement de coupes pétrolières telles que des kérosènes ou des essences dites catalytiques ou de distillation directe.When the petroleum charge to be treated is, for example, a cut containing between 20 and 300 ppm of mercaptans and less than 150 ppm of water soluble in the charge to be treated, the catalytic oxidation reaction will be advantageously carried out at a higher temperature. at 30 ° C and preferably between 40 and 120 ° C. These conditions are aimed in particular at the softening of petroleum fractions such as kerosene or so-called catalytic or direct distillation gasolines.
De la même façon, lorsque la charge pétrolière à traiter est par exemple une coupe contenant entre 300 et 3000 p.p.m. de mercaptans et des quantités d'eau soluble supérieures à 100 p.p.m., on procèdera à la réaction d'oxydation catalytique à une température supérieure à 40°C et, de préférence, comprise entre 50 et 140°C. Ces conditions visent en particulier l'adoucissement de coupes pétrolières telles que les essences légères.Similarly, when the petroleum charge to be treated is for example a cut containing between 300 and 3000 ppm of mercaptans and quantities of soluble water greater than 100 ppm, the catalytic oxidation reaction will be carried out at a temperature higher than 40 ° C and preferably between 50 and 140 ° C. These conditions are aimed in particular at the softening of petroleum cuts such as light petrol.
Dans les deux cas précédents, le taux d'hydratation optimum du support dont dépend l'activité catalytique sera maintenu à une valeur déterminée, généralement comprise entre 1 et 25% en poids, malgré les variations possibles de la charge, en faisant par exemple fluctuer la température de quelques degrés autour d'une température d'équilibre, suivant que le support tend lui-même à s'hydrater ou à se déshydrater.In the two previous cases, the optimum level of hydration of the support on which the catalytic activity depends will be maintained at a determined value, generally between 1 and 25% by weight, despite possible variations in the charge, for example by fluctuating the temperature of a few degrees around an equilibrium temperature, depending on whether the support itself tends to hydrate or dehydrate.
Ce taux pourra également être maintenu en élevant de façon substantielle la température de réaction et en injectant une certaine quantité d'eau, qui pourra varier en fonction des teneurs en eau et en mercaptans de la charge.This rate can also be maintained by substantially raising the reaction temperature and by injecting a certain amount of water, which can vary depending on the water and mercaptan contents of the feed.
Selon un mode de mise en oeuvre particulièrement avantageux du procédé selon l'invention, on pourra donc procéder à une injection d'eau dans la coupe pétrolière, en amont de la zone réactionnelle, en vue d'ajuster plus facilement la teneur en eau du support dans la gamme prédéterminée de teneurs en eau.According to a particularly advantageous embodiment of the method according to the invention, it is therefore possible to inject water into the petroleum cut, upstream of the reaction zone, in order to more easily adjust the water content of the support in the predetermined range of water contents.
Une alternative possible consistera, par exemple, à réaliser la réaction à une température inférieure de quelques degrés à la température d'équilibre ci-dessus mentionnée et à envoyer, de façon périodique, ou en continu, une quantité déterminée de charge peu hydratée à une température plus élevée.A possible alternative will consist, for example, in carrying out the reaction at a temperature a few degrees lower than the equilibrium temperature mentioned above and in sending, periodically, or continuously, a determined quantity of poorly hydrated filler to a higher temperature.
En vue d'adapter la température de la réaction d'oxydation des mercaptans, on utilisera des moyens permettant de mesurer la teneur en eau de la charge et de l'effluent, ou du support catalytique, ainsi que les teneurs en mercaptans de la charge et de l'effluent.In order to adapt the temperature of the mercaptan oxidation reaction, means will be used to measure the water content of the feed and of the effluent, or of the catalytic support, as well as the mercaptan contents of the feed. and effluent.
Parmi les moyens de mesure de teneur en eau du support, on peut utiliser, d'une part, des systèmes permettant, de façon connue en soi, le prélèvement d'échantillons de support catalytique sans arrêt de l'unité. A partir de ces échantillons, il est facile de mesurer, par la méthode de Karl FISCHER, le taux d'hydratation du support et de ramener ensuite ce taux à sa valeur optimale par régulation de la température, conformément à la présente invention. On peut également utiliser un système de sonde placé directement à l'intérieur du lit catalytique.Among the means for measuring the water content of the support, one can use, on the one hand, systems allowing, in a manner known per se, the sampling of catalytic support samples without stopping the unit. From these samples, it is easy to measure, by the Karl FISCHER method, the hydration rate of the support and then to reduce this rate to its optimal value by temperature regulation, in accordance with the present invention. It is also possible to use a probe system placed directly inside the catalytic bed.
Parmi les moyens de mesure de la teneur en mercaptans de la charge, tant à l'entrée du réacteur qu'à sa sortie, on peut utiliser des analyseurs chromatographiques de type connu en soi ou, à défaut, effectuer des prélèvements périodiques pour analyse selon une méthode telle que celle dite du nitrate d'argent.Among the means for measuring the mercaptan content of the feed, both at the inlet of the reactor and at its outlet, it is possible to use chromatographic analyzers of a type known per se or, failing this, to carry out periodic samples for analysis according to a method such as that called silver nitrate.
Un autre moyen, facile à mettre en oeuvre, consiste à utiliser deux sondes de mesure en continu de la teneur en eau de la charge, la première étant située en amont du lit catalytique, la seconde en aval de celui-ci. Parmi les sondes permettant de mesurer en continu la teneur en eau de la charge, on peut utiliser des sondes du commerce, telles que celles commercialisées par la Société Endress Hauser, ou des sondes capacitives du type décrit dans la demande de brevet français N° 2.512.958. La différence entre la teneur mesurée en aval et celle mesurée en amont permet alors de déterminer aisément, compte tenu de la quantité de mercaptans transformés en disulfures, de combien croît ou décroît la teneur en eau du support. Une modification de la température réactionnelle (ou de la quantité d'eau additionnelle injectée) permet alors de rendre sensiblement constante la teneur en eau du support catalytique dans le réacteur.Another means, easy to implement, consists in using two probes for continuous measurement of the water content of the feed, the first being located upstream of the catalytic bed, the second downstream of the latter. Among the probes making it possible to continuously measure the water content of the feed, it is possible to use commercial probes, such as those sold by the Endress Hauser Company, or capacitive probes of the type described in French patent application No. 2.512 .958. The difference between the content measured downstream and that measured upstream then makes it easy to determine, taking into account the quantity of mercaptans transformed into disulphides, by how much increases or decreases the water content of the support. A modification of the reaction temperature (or of the quantity of additional water injected) then makes it possible to make the water content of the catalytic support in the reactor substantially constant.
Un premier avantage de la présente invention découle du principe même de la réaction, qui est lié à l'absence de base ou de solution caustique dans la charge et dans les effluents : d'une part, il n'est plus besoin de séparer les bases, ni de les retraiter, ni de disposer d'une coûteuse unité de destruction de celles-ci; d'autre part, l'absence de base, même à l'état de traces dans les charges pétrolières traitées, fait de ces dernières d'excellents produits pour une utilisation directe ultérieure.A first advantage of the present invention follows from the very principle of the reaction, which is linked to the absence of base or of caustic solution in the feed and in the effluents: on the one hand, there is no longer any need to separate the bases, neither to reprocess them, nor to have an expensive unit of destruction of these; on the other hand, the absence of base, even in trace amounts in the treated petroleum charges, makes the latter excellent products for subsequent direct use.
Un deuxième avantage de la présente invention résulte du fait que l'eau réactionnelle est entraînée par la charge pétrolière elle-même pendant l'adoucissement. Il n'est donc plus besoin de séchages coûteux du support par injection de solvants dans la charge, ou par utilisation de dessicant dans le lit catalytique.A second advantage of the present invention results from the fact that the reaction water is entrained by the petroleum charge itself during the softening. There is therefore no longer any need for costly drying of the support by injecting solvents into the feed, or by using a desiccant in the catalytic bed.
Un troisième avantage de la présente invention découle du fait que la réaction d'adoucissement est réalisée à température plus élevée que selon l'art antérieur: la cinétique de la réaction est améliorée, et il devient possible d'effectuer la réaction en continu à une vitesse spatiale horaire supérieure à celle de l'art antérieur. Cette vitesse spatiale horaire pourra être de l'ordre de 1 à 8 v.v.h. (volume de charge par volume de catalyseur et par heure) pour des charges du type kérosène et de l'ordre de 1 à 10 v.v.h. pour les charges du type essence. Il en résulte une économie importante sur les coûts de construction de l'unité d'adoucissement, car la taille de celle-ci peut être réduite en conséquence. Enfin, la cinétique de réaction étant améliorée, il est aussi possible de traiter des charges plus réfractaires, ou plus lourdes, difficilement adoucissables selon la technique antérieure, ou de réaliser l'adoucissage des mercaptans en continu là où seules des techniques en discontinu étaient applicables jusqu'à présent.A third advantage of the present invention results from the fact that the softening reaction is carried out at a higher temperature than according to the prior art: the kinetics of the reaction are improved, and it becomes possible to carry out the reaction continuously at a hourly space velocity greater than that of the prior art. This hourly space speed may be of the order of 1 to 8 v.v.h. (charge volume per catalyst volume and per hour) for kerosene type charges and of the order of 1 to 10 v.v.h. for petrol type loads. This results in a significant saving on the construction costs of the softening unit, since the size thereof can be reduced accordingly. Finally, the reaction kinetics being improved, it is also possible to treat more refractory or heavier fillers which are difficult to soften according to the prior art, or to carry out the softening of the mercaptans continuously where only discontinuous techniques were applicable. until now.
Un quatrième avantage de la présente invention résulte enfin de ce que la réaction d'adoucissement est réalisée en phase homogène, sans formation de gommes, ce qui entraîne une diminution des coûts de lavage et d'entretien, et une simplification des équipements situés en avals de l'unité.A fourth advantage of the present invention finally results from the fact that the softening reaction is carried out in homogeneous phase, without the formation of gums, which leads to a reduction in washing and maintenance costs, and a simplification of the equipment located downstream. of unity.
Le procédé conforme à l'invention est bien adapté à l'adoucissement de toutes les coupes pétrolières et, en particulier, à l'adoucissement des essences et des kérosènes. En effet, ces coupes pétrolières ne contiennent que très peu d'eau (une quantité généralement inférieure à 500 p.p.m.) et, par conséquent, l'élévation de température nécessaire pour solubiliser les molécules d'eau engendrées in situ lors de la réaction d'adoucissement sera maintenue dans des limites acceptables.The process according to the invention is well suited to the softening of all petroleum cuts and, in particular, the softening of petrol and kerosene. Indeed, these petroleum fractions contain only very little water (an amount generally less than 500 ppm) and, consequently, the rise in temperature necessary to dissolve the water molecules generated in situ during the reaction of softening will be kept within acceptable limits.
De plus, lorsque la charge pétrolière à traiter contiendra des quantités relativement importantes de mercaptans, par exemple pour des charges dont la teneur en mercaptans est supérieure à 300 p.p.m., il sera possible de compenser la formation in situ d'une quantité correspondante de molécules d'eau, par exemple en séchant au préalable la charge sur des tamis moléculaires, (ou en la refroidissant, puis en la décantant), afin de limiter au maximum sa teneur initiale en eau.In addition, when the petroleum charge to be treated contains relatively large quantities of mercaptans, for example for charges whose mercaptan content is greater than 300 ppm, it will be possible to compensate for the formation in situ of a corresponding quantity of molecules d water, for example by drying the charge beforehand on molecular sieves, (or by cooling it, then by decanting it), in order to limit as much as possible its initial water content.
Hormis l'absence de base aqueuse ainsi que les conditions de température et de vitesse spatiale horaire plus élevées que selon la technique antérieure, les autres conditions de la réaction d'adoucissement des charges pétrolières selon l'invention sont globalement les mêmes que celles décrites dans l'art antérieur. Ces conditions réactionnelles pourront, par exemple, être les suivantes:
Parmi les supports utilisables conformément à la présente invention on pourra employer, de façon connue en soi, des supports à base de charbon actif, d'alumine, d'argile, d'aluminosilicates, de silicates ou des mélanges de ces derniers.Among the supports which can be used in accordance with the present invention, it is possible to use, in a manner known per se, supports based on activated carbon, on alumina, of clay, aluminosilicates, silicates or mixtures of these.
Comme chélate métallique, on pourra déposer sur le support tout chélate utilisé dans ce but dans la technique antérieure, en particulier les phtalocyanines, les porphyrines ou les corrines métalliques. On préfère particulièrement la phtalocyanine de cobalt et la phtalocyanine de vanadium. On utilise, de préférence, la phtalocyanine métallique sous forme d'un dérivé de cette dernière, avec une préférence particulière pour leurs sulfonates disponibles dans le commerce, comme par exemple le mono-ou le disulfonate de phtalocyanine de cobalt et des mélanges de ceux-ci.As the metal chelate, any chelate used for this purpose in the prior art, especially phthalocyanines, porphyrins or metallic corrines, can be deposited on the support. Particularly preferred is cobalt phthalocyanine and vanadium phthalocyanine. Preferably, metallic phthalocyanine is used in the form of a derivative of the latter, with particular preference for their commercially available sulfonates, such as, for example, cobalt phthalocyanine disulphonate and mixtures thereof. this.
Une forme de mise en oeuvre de l'invention sera décrite ci-après en détail, à titre d'exemple non limitatif, en référence à la figure unique du dessin annexé.An embodiment of the invention will be described below in detail, by way of nonlimiting example, with reference to the single figure of the accompanying drawing.
Cette figure représente un schéma de mise en oeuvre en continu du procédé conforme à l'invention.This figure represents a diagram of continuous implementation of the method according to the invention.
Dans cette forme de mise en oeuvre, l'alimentation du réacteur 1 en coupe pétrolière à adoucir s'effectue par la ligne 2, dans laquelle l'agent oxydant, de l'air par exemple, est introduit directement par la ligne 3. La coupe pétrolière traitée est évacuée par la ligne 4, qui alimente un système de filtre 5, destiné à éliminer les traces d'eau et de soufre naissant souvent produit au cours de l'oxydation des mercaptans et non retenu par le support. La charge traitée est ensuite transférée par la ligne 6 à une enceinte de stockage 7.In this embodiment, the supply of the reactor 1 in petroleum cut to be softened is carried out by
Conformément à l'invention, des sondes de mesure 8 et 9, placées respectivement en amont et en aval du réacteur, permettent de déterminer en permanence les teneurs en eau et en mercaptans à l'entrée et à la sortie du réacteur 1. Il est ainsi possible de vérifier en continu si la teneur en eau du support catalytique croît ou décroît. Une action corrective peut alors être réalisée par modification de la quantité de chaleur apportée à la charge par un échangeur thermique 10 placé sur la ligne 2 en amont du réacteur 1. Une partie de la chaleur apportée par l'échangeur 10 peut ensuite être récupérée à l'aide de l'échangeur 11 disposé sur la ligne 4 en aval du réacteur 1 et à partir de l'eau formée éliminée en 5.In accordance with the invention, measurement probes 8 and 9, placed respectively upstream and downstream of the reactor, make it possible to permanently determine the water and mercaptan contents at the inlet and at the outlet of the reactor 1. It is thus it is possible to continuously check whether the water content of the catalytic support increases or decreases. A corrective action can then be carried out by modifying the quantity of heat supplied to the load by a heat exchanger 10 placed on the
De l'eau peut éventuellement être injectée dans la charge par la ligne 12, placée ici entre la phase de régulation en 10 de la température et la phase d'oxydation catalytique en 1 de la coupe pétrolière. Dans cette forme de mise en oeuvre de l'invention, la température de la charge à la sortie de l'échangeur 10 sera légèrement supérieure à celle requise pour maintenir la teneur en eau du support égale à sa valeur de consigne, et un appoint d'eau sera par exemple introduit par la ligne 12 pour rendre cette teneur égale à la valeur de consigne, malgré les fluctuations des teneurs en eau et en mercaptans ou celles de la température de la charge.Water can optionally be injected into the feedstock through line 12, placed here between the temperature regulation phase at 10 and the catalytic oxidation phase at 1 of the petroleum cut. In this embodiment of the invention, the temperature of the charge at the outlet of the exchanger 10 will be slightly higher than that required to keep the water content of the support equal to its set value, and an additional d water will, for example, be introduced via line 12 to make this content equal to the set value, despite fluctuations in the contents of water and mercaptans or those of the temperature of the charge.
Cette forme de mise en oeuvre de l'invention présente l'avantage qu'il est plus facile d'assurer une régulation en jouant sur une quantité d'eau injectée qu'en faisant varier la température de la charge.This embodiment of the invention has the advantage that it is easier to ensure regulation by varying the amount of water injected than by varying the temperature of the charge.
Ainsi que le montreront les exemples ci-après, qui ne présentent pas, non plus, de caractère limitatif, la mise en oeuvre de l'invention se révèle particulièrement efficace dans l'adoucissement des coupes pétrolières, même de celles réputées difficiles à traiter.As will be shown by the examples below, which are not limiting either, the implementation of the invention proves to be particularly effective in softening petroleum fractions, even those deemed to be difficult to treat.
Le support catalytique utilisé dans cet exemple a été préparé comme décrit dans la demande de brevet européen N° 252.853. Après imprégnation du support avec une phtalocyanine de cobalt sulfonée du type commercialisé par la Société Française PROCATALYSE sous l'appellation "LCPS", ce catalyseur se présente sous la forme d'un granulat (de surface spécifique d'environ 50 m²/g, qui contient principalement environ 1,5 kg de chélate par m³ de support. Ce support contient environ 10% en poids de carbone, 20% en poids de silicium, et 8 à 9% en poids de sels de potassium sous forme de sels insolubles.The catalytic support used in this example was prepared as described in European patent application No. 252,853. After impregnation of the support with a sulfonated cobalt phthalocyanine of the type marketed by the French company PROCATALYSE under the name "LCPS", this catalyst is in the form of an aggregate (with a specific surface of approximately 50 m² / g, which contains mainly about 1.5 kg of chelate per m³ of support This support contains approximately 10% by weight of carbon, 20% by weight of silicon, and 8 to 9% by weight of potassium salts in the form of insoluble salts.
Des études de ce support catalytique sur pilote montrent que la teneur en eau optimum est comprise entre 1 et environ 10% en poids: au-dessous de 1% en poids de teneur en eau, le catalyseur se désactive rapidement, alors que la désactivation est beaucoup plus lente au-delà de 1% et jusqu'à 10 ou 11% en poids.Studies of this catalytic support on pilot show that the optimum water content is between 1 and about 10% by weight: below 1% by weight of water content, the catalyst deactivates quickly, while deactivation is much slower beyond 1 % and up to 10 or 11% by weight.
On prépare deux lots, identiques de catalyseur, L₁ et L₂, que l'on place directement dans un réacteur pilote, dont le rapport de la hauteur au diamètre est ici d'environ 5. On s'assure ensuite du bon taux initial d'hydratation du catalyseur (5 à 6% en poids d'eau), en faisant passer sur celui-ci, à température ambiante, un volume égal d'éthanol industriel à une vitesse spatiale horaire de 1 v.v.h.Two identical batches of catalyst, L₁ and L₂, are prepared, which are placed directly in a pilot reactor, the ratio of the height to the diameter here being around 5. We then make sure of the correct initial rate of hydration of the catalyst (5 to 6% by weight of water), by passing over it, at ambient temperature, an equal volume of industrial ethanol at an hourly space speed of 1 vvh
On dispose de deux charges C₁ et C₂ :
- la charge C₁ est une charge de type kérosène, issue d'un mélange de bruts isthmus-cactus et de brut Maya, contenant environ 80 p.p.m. de mercaptans et 100 p.p.m. d'eau ;
- la charge C₂ est une charge de type essence, contenant environ 300 p.p.m. de mercaptans et 150 p.p.m. d'eau.There are two charges C₁ and C₂:
the charge C₁ is a charge of the kerosene type, resulting from a mixture of isthmus-cactus crudes and Mayan crude, containing approximately 80 ppm of mercaptans and 100 ppm of water;
- The charge C₂ is a gasoline type charge, containing approximately 300 ppm of mercaptans and 150 ppm of water.
Ces charges présentent les caractéristiques suivantes:
On utilise de l'air comme agent oxydant, et aucune solution basique aqueuse n'est employée. On fait passer la charge C₁ sur le premier lot L₁ dans des conditions opératoires qui sont les suivantes:
Au cours du test T1, on constate que la teneur en mercaptans de la charge C₁ traitée est inférieure à 5 p.p.m. pendant les soixante premiers jours environ, puis que la teneur en mercaptans des effluents remonte progressivement et dépasse 10 p.p.m. au bout de 90 jours, du fait de la saturation progressive en eau du support catalytique; il est alors facile de constater que de l'eau réactionnelle a été captée par le support, dont le taux d'hydratation est passé à plus de 10%.During the T1 test, it is noted that the mercaptan content of the treated charge C₁ is less than 5 ppm during the first sixty days approximately, then that the mercaptan content of the effluents rises gradually and exceeds 10 ppm after 90 days, due to the progressive saturation in water of the catalytic support; it is then easy to see that the reaction water has been captured by the support, the hydration rate of which has risen to more than 10%.
On procède alors au test T2, en montant la température de la charge à 80°C et en faisant passer la vitesse spatiale horaire à 4 v.v.h.. On constate que la teneur en mercaptans de la charge C₁ traitée redevient inférieure à 5 p.p.m., pendant les 6 premiers jours, puis que cette teneur remonte brusquement et dépasse 10 p.p.m. au bout de 7 jours, de fait cette fois de la déshydratation du support catalytique, dont le taux d'hydratation est devenu inférieur à 1%.One then proceeds to the T2 test, by raising the temperature of the charge to 80 ° C. and passing the hourly space speed to 4 vvh. It is noted that the mercaptan content of the treated charge C₁ becomes again less than 5 ppm, during the First 6 days, then this content rises sharply and exceeds 10 ppm after 7 days, this time due to dehydration of the catalytic support, the hydration rate of which has become less than 1%.
On modifie alors les conditions opératoires pour procéder au test T3 conforme au procédé selon l'invention: on constate que la teneur en mercaptans de la charge C₁ traitée reste toujours inférieure à 5 p.p.m., après 300 jours de marche. En effet, le taux d'hydratation du support est resté sensiblement constant, du fait de l'élévation de température de 40 à 45°C, ce qui permet de retirer avec la charge toute l'eau réactionnelle de la conversion des mercaptans en disulfures.The operating conditions are then modified to carry out the T3 test in accordance with the method according to the invention: it is found that the mercaptan content of the treated charge C₁ always remains below 5 ppm, after 300 days of operation. Indeed, the hydration rate of the support has remained substantially constant, due to the temperature rise from 40 to 45 ° C, which allows to remove with the charge all the reaction water from the conversion of mercaptans to disulfides .
On modifie à nouveau les conditions de réaction pour procéder au test T4, également conforme au procédé selon l'invention: on constate encore que la teneur en mercaptans de la charge C₁ traitée reste toujours inférieure à 5 p.p.m., même après 300 jours de marche. En effet, le taux d'hydratation du support est maintenu à une valeur constante d'environ 6%, en dépit de la forte augmentation de la température de (de 45 à 80°C) et de la vitesse spatiale horaire (de 1 à 4 v.v.h.) grâce à une injection d'eau dans la charge en quantité suffisante (+ 577 p.p.m.) pour que, malgré l'augmentation importante de son pouvoir solvant à 80°C, la charge ne puisse plus dissoudre dans le réacteur que la quantité d'eau réactionnelle produite.The reaction conditions are again modified to carry out the T4 test, also in accordance with the method according to the invention: it is also found that the mercaptan content of the treated C₁ charge always remains less than 5 p.p.m., even after 300 days of operation. Indeed, the hydration rate of the support is maintained at a constant value of around 6%, despite the sharp increase in temperature from (from 45 to 80 ° C) and in hourly space speed (from 1 to 4 vvh) thanks to a sufficient injection of water into the feed (+ 577 ppm) so that, despite the significant increase in its solvent power at 80 ° C, the feed can no longer dissolve in the reactor except the amount of reaction water produced.
Un autre essai est alors pratiqué sur la charge C₂, qui est cette fois une essence beaucoup plus riche en eau et surtout en mercaptans. Les conditions opératoires sont alors les suivantes:
On procède d'abord sur le lot L₂ avec la charge C₂ à un test dans les conditions décrites en T₅: on constate que dans des conditions de températures peu différentes de celles pratiquées dans la technique antérieure, la quantité d'eau réactionnelle due à la quantité relativement importante de mercaptans dans l'essence C₂ oblige à arrêter l'essai au bout de 28 jours.First, on batch L₂ with charge C₂, a test is carried out under the conditions described in T₅: it can be seen that under temperature conditions little different from those practiced in the prior art, the amount of reaction water due to the relatively large quantity of mercaptans in gasoline C₂ requires to stop the test after 28 days.
On procède donc à une modification des conditions réactionnelles pour utiliser celles décrites en T₆, et l'on constate que, comme pour les charges de kérosène, le procédé selon l'invention permet de maintenir la teneur en mercaptans constamment en dessous de 10 p.p.m., par une action sur le pouvoir solvant de la charge en fonction de la température, de façon similaire au test T4 décrit antérieurement.The reaction conditions are therefore modified to use those described in T₆, and it can be seen that, as with kerosene feedstocks, the process according to the invention makes it possible to keep the mercaptan content constantly below 10 ppm, by an action on the solvent power of the load as a function of the temperature, similar to the T4 test described previously.
Claims (12)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8911781A FR2651791B1 (en) | 1989-09-08 | 1989-09-08 | METHOD OF SOFTENING IN A FIXED BED OF OIL CUTS. |
FR8911781 | 1989-09-08 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0416979A1 true EP0416979A1 (en) | 1991-03-13 |
EP0416979B1 EP0416979B1 (en) | 1997-10-29 |
Family
ID=9385274
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90402387A Expired - Lifetime EP0416979B1 (en) | 1989-09-08 | 1990-08-29 | Process for fixed bed sweetening of petroleum fractions |
Country Status (8)
Country | Link |
---|---|
US (1) | US5069777A (en) |
EP (1) | EP0416979B1 (en) |
JP (1) | JPH03174493A (en) |
KR (1) | KR910006460A (en) |
CA (1) | CA2024834A1 (en) |
DE (1) | DE69031644D1 (en) |
FR (1) | FR2651791B1 (en) |
ZA (1) | ZA906770B (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2666344B1 (en) * | 1990-09-03 | 1992-12-18 | Total France | FIXED BED SOFTENING PROCESS OF ACID OIL DISTILLATES WITH CUTTING TEMPERATURES BETWEEN APPROXIMATELY 125 AND APPROXIMATELY 350 DEGREE C. |
US5633216A (en) * | 1992-03-03 | 1997-05-27 | Institut Francais Du Petrole | Process for sweetening petroleum cuts without regular addition of alkaline solution using a basic solid catalyst |
FR2688223B1 (en) * | 1992-03-05 | 1994-05-20 | Institut Francais Petrole | NEW PROCESS FOR SOFTENING OIL CUTS WITHOUT REGULAR ADDITION OF AQUEOUS ALKALINE SOLUTION, USING A BASIC SOLID CATALYST. |
EP0638628B1 (en) * | 1993-08-04 | 1998-12-16 | Institut Francais Du Petrole | Process for sweetening of petroleum fractions without regular addition of an aqueous alkaline solution, using a solid basic catalyst |
US5413701A (en) * | 1993-11-15 | 1995-05-09 | Uop | Process for sweetening a sour hydrocarbon fraction using a supported metal chelate and a solid base |
US6709639B1 (en) * | 1996-09-24 | 2004-03-23 | Institut Francais Du Petrole | Apparatus for purification of raw gasoline from catalytic cracking |
CN104266176A (en) * | 2014-09-09 | 2015-01-07 | 翟永才 | Energy-saving environment-friendly boiler |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3686094A (en) * | 1968-12-31 | 1972-08-22 | Inst Francais Du Petrole | Process for oxidizing mercaptans to disulfides in the presence of solid catalytic masses |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3230180A (en) * | 1963-02-07 | 1966-01-18 | Universal Oil Prod Co | Metal phthalocyanine catalyst preparation |
US4207173A (en) * | 1976-03-04 | 1980-06-10 | Uop Inc. | Sweetening of hydrocarbon distillates utilizing a tetra-alkyl guanidine with phthalocyanine catalyst |
US4124531A (en) * | 1977-01-03 | 1978-11-07 | Uop Inc. | Catalytic composite for the treatment of sour petroleum distillates |
US4248694A (en) * | 1979-05-17 | 1981-02-03 | Uop Inc. | Process for treating a sour petroleum distillate |
US4290917A (en) * | 1979-10-01 | 1981-09-22 | Uop Inc. | Method of manufacturing a catalytic composite |
US4298463A (en) * | 1980-07-11 | 1981-11-03 | Uop Inc. | Method of treating a sour petroleum distillate |
US4574121A (en) * | 1983-11-29 | 1986-03-04 | Uop Inc. | Metal chelate mercaptan oxidation catalyst |
US4498978A (en) * | 1983-11-29 | 1985-02-12 | Uop Inc. | Catalytic oxidation of mercaptan in petroleum distillate |
US4498977A (en) * | 1983-11-29 | 1985-02-12 | Uop Inc. | Catalytic oxidation of mercaptan in petroleum distillate |
US4502949A (en) * | 1984-02-15 | 1985-03-05 | Uop Inc. | Catalytic oxidation of mercaptan in petroleum distillate |
US4753722A (en) * | 1986-06-17 | 1988-06-28 | Merichem Company | Treatment of mercaptan-containing streams utilizing nitrogen based promoters |
US4913802A (en) * | 1989-05-08 | 1990-04-03 | Uop | Process for sweetening a sour hydrocarbon fraction |
-
1989
- 1989-09-08 FR FR8911781A patent/FR2651791B1/en not_active Expired - Fee Related
-
1990
- 1990-08-24 ZA ZA906770A patent/ZA906770B/en unknown
- 1990-08-29 EP EP90402387A patent/EP0416979B1/en not_active Expired - Lifetime
- 1990-08-29 DE DE69031644T patent/DE69031644D1/en not_active Expired - Lifetime
- 1990-09-07 CA CA002024834A patent/CA2024834A1/en not_active Abandoned
- 1990-09-08 KR KR1019900014235A patent/KR910006460A/en not_active Application Discontinuation
- 1990-09-10 JP JP2239775A patent/JPH03174493A/en active Pending
- 1990-09-10 US US07/579,820 patent/US5069777A/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3686094A (en) * | 1968-12-31 | 1972-08-22 | Inst Francais Du Petrole | Process for oxidizing mercaptans to disulfides in the presence of solid catalytic masses |
Also Published As
Publication number | Publication date |
---|---|
FR2651791B1 (en) | 1994-05-20 |
JPH03174493A (en) | 1991-07-29 |
ZA906770B (en) | 1991-06-26 |
US5069777A (en) | 1991-12-03 |
DE69031644D1 (en) | 1997-12-04 |
KR910006460A (en) | 1991-04-29 |
CA2024834A1 (en) | 1991-03-09 |
FR2651791A1 (en) | 1991-03-15 |
EP0416979B1 (en) | 1997-10-29 |
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